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Sample records for hybrid silica monolith

  1. Aptamer modified organic-inorganic hybrid silica monolithic capillary columns for highly selective recognition of thrombin.

    Science.gov (United States)

    Deng, Nan; Liang, Zhen; Liang, Yu; Sui, Zhigang; Zhang, Liyuan; Wu, Qi; Yang, Kaiguang; Zhang, Lihua; Zhang, Yukui

    2012-12-04

    A novel kind of aptamer modified organic-inorganic hybrid silica monolithic capillary column has been developed, via the covalent bonding of 5'-NH(2)-modified aptamer for human α-thrombin on hybrid silica monolith, prepared by sol-gel method, with tetraethoxysilane and 3-aminopropyltriethoxysilane as precursors. Due to the large specific surface area of the hybrid matrix, the average coverage density of aptamer reached 568 pmol/μL, and the thrombin binding capacity was 1.15 μg/μL, 14 times higher than that of aptamer modified open tubular capillaries. By such an affinity capillary column, the limit of detection of thrombin was decreased to 3.4 nM with a UV detector. Furthermore, even when thrombin was mixed with 1000 times more concentrated human serum, it could be selectively enriched and detected with the signal-to-noise ratio as ca.10. These results indicate that the developed preparation strategy for aptamer based hybrid silica monolithic capillary column might provide an effective method to achieve highly selective recognition of trace targets.

  2. Facile preparation of organic-silica hybrid monolith for capillary hydrophilic liquid chromatography based on "thiol-ene" click chemistry.

    Science.gov (United States)

    Chen, Ming-Luan; Zhang, Jun; Zhang, Zheng; Yuan, Bi-Feng; Yu, Qiong-Wei; Feng, Yu-Qi

    2013-04-05

    In this work, a one-step approach to facile preparation of organic-inorganic hybrid monoliths was successfully developed. After vinyl-end organic monomers and azobisisobutyronitrile (AIBN) were mixed with hydrolyzed tetramethoxysilane (TMOS) and 3-mercaptopropyltrimethoxysilane (MPTMS), the homogeneous mixture was introduced into a fused-silica capillary for simultaneous polycondensation and "thiol-ene" click reaction to form the organic-silica hybrid monoliths. By employing this strategy, two types of organic-silica hybrid monoliths with positively charged quaternary ammonium and amide groups were prepared, respectively. The functional groups were successfully introduced onto the monoliths during the sol-gel process with "thiol-ene" click reaction, which was demonstrated by ζ-potential assessment, energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared (FT-IR) spectroscopy. The porous structure of the prepared monolithic columns was examined by scanning electron microscopy (SEM), nitrogen adsorption-desorption measurement, and mercury intrusion porosimetry. These results indicate the prepared organic-silica hybrid monoliths possess homogeneous column bed, large specific surface area, good mechanical stability, and excellent permeability. The prepared monolithic columns were then applied for anion-exchange/hydrophilic interaction liquid chromatography. Different types of analytes, including benzoic acids, inorganic ions, nucleosides, and nucleotides, were well separated with high column efficiency around 80,000-130,000 plates/m. Taken together, we present a facile and universal strategy to prepare organic-silica hybrid monoliths with a variety of organic monomers using one-step approach. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. One-pot preparation of mercaptotetrazole-silica hybrid monoliths by the thiol-ene click reaction for mixed-mode capillary liquid chromatography.

    Science.gov (United States)

    Wang, Haojiang; Hu, Wenli; Zheng, Qiong; Bian, Wei; Lin, Zian

    2017-06-01

    A novel mercaptotetrazole-silica hybrid monolithic column was prepared for capillary liquid chromatography, in which the thiol-end mercaptotetrazole was mixed with hydrolyzed γ-methacryloxypropyltrimethoxysilane and tetramethyloxysilane for the co-polycondensation and thiol-ene click reaction in a one-pot process. The effects of the molar ratio of silanes, the amount of mercaptotetrazole, and the volume of porogen on the morphology, permeability and pore properties of the as-prepared mercaptotetrazole-silica hybrid monoliths were investigated in detail. A series of test compounds including alkylbenzenes, amides and anilines were employed for evaluating the retention behaviors of the mercaptotetrazole-silica hybrid monolithic columns. The results demonstrated that the mercaptotetrazole-silica hybrid monoliths exhibited hydrophobic, hydrophilic as well as ion-exchange interaction. The run-to-run, column-to-column and batch-to-batch reproducibilities of the mercaptotetrazole-silica hybrid monoliths were satisfactory with the relative standard deviations less than 1.4 (n = 5), 3.9 (n = 3) and 4.0% (n = 5), respectively. In addition, the mercaptotetrazole-silica hybrid monolith was further applied to the separation of sulfonamides, nucleobases and protein tryptic digests. These successful applications confirmed the promising potential of the mercaptotetrazole-silica hybrid monolith in the separation of complex samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Aptamer-based organic-silica hybrid affinity monolith prepared via "thiol-ene" click reaction for extraction of thrombin.

    Science.gov (United States)

    Wang, Zheng; Zhao, Jin-cheng; Lian, Hong-zhen; Chen, Hong-yuan

    2015-06-01

    A novel strategy for preparing aptamer-based organic-silica hybrid monolithic column was developed via "thiol-ene" click chemistry. Due to the large specific surface area of the hybrid matrix and the simplicity, rapidness and high efficiency of "thiol-ene" click reaction, the average coverage density of aptamer on the organic-silica hybrid monolith reached 420 pmol μL(-1). Human α-thrombin can be captured on the prepared affinity monolithic column with high specificity and eluted by NaClO4 solution. N-p-tosyl-Gly-Pro-Arg p-nitroanilide acetate was used as the sensitive chromogenic substrate of thrombin. The thrombin enriched by this affinity column was detected with a detection of limit of 0.01 μM by spectrophotometry. Furthermore, the extraction recovery of thrombin at 0.15 μM in human serum was 91.8% with a relative standard deviation of 4.0%. These results indicated that "thiol-ene" click chemistry provided a promising technique to immobilize aptamer on organic-inorganic hybrid monolith and the easily-assembled affinity monolithic material could be used to realize highly selective recognition of trace proteins.

  5. One-pot preparation of glutathione-silica hybrid monolith for mixed-mode capillary liquid chromatography based on "thiol-ene" click chemistry.

    Science.gov (United States)

    Lin, Zian; Tan, Xiaoqing; Yu, Ruifang; Lin, Jiashi; Yin, Xiaofei; Zhang, Lan; Yang, Huanghao

    2014-08-15

    A novel glutathione (GSH)-silica hybrid monolithic column synthesized via a combination of thiol-ene click reaction and one-pot process was described, where thiol-end GSH organic monomer and 2,2-azobisisobutyronitrile (AIBN) were mixed with hydrolyzed tetramethyloxysilane (TMOS) and γ-methacryloxypropyltrimethoxysilane (γ-MAPS) and then introduced into a fused-silica capillary for simultaneous polycondensation and "thiol-ene" click reaction to form the GSH-silica hybrid monolith. The effects of the molar ratio of TMOS/γ-MAPS, the amount of GSH, and the volume of porogen on the morphology, permeability and pore properties of the prepared GSH-silica hybrid monoliths were studied in detail. A uniform monolithic network with high porosity was obtained. A series of test compounds including alkylbenzenes, amides, and anilines were used to evaluate the retention behaviors of the GSH-silica hybrid monolithic column. The results demonstrated that the prepared GSH-silica hybrid monolith exhibited multiple interactions including hydrophobicity, hydrophilicity, as well as cation exchange interaction. The run-to-run, column-to-column and batch-to-batch reproducibilities of the GSH-silica hybrid monolith for phenols' retention were satisfactory with the relative standard deviations (RSDs) less than 1.3% (n=5), 2.6% (n=3) and 3.2% (n=3), respectively, indicating the effectiveness and practicability of the proposed method. In addition, the GSH-silica hybrid monolith was applied to the separation of nucleotides, peptides and protein tryptic digests, respectively. The successful applications suggested the potential of the GSH-silica hybrid monolith in complex sample analysis.

  6. Hybrid organic-inorganic silica monolith with hydrophobic/strong cation-exchange functional groups as a sorbent for micro-solid phase extraction.

    Science.gov (United States)

    Zheng, Ming-Ming; Ruan, Ge-Deng; Feng, Yu-Qi

    2009-11-06

    A hybrid organic-inorganic silica monolith with hydrophobic and strong cation-exchange functional groups was prepared and used as a sorbent for micro-solid phase extraction (micro-SPE). The hybrid silica monolith functionalized with octyl and thiol groups was conveniently synthesized by hydrolysis and polycondensation of a mixture of tetraethoxysilane (TEOS), n-octyltriethoxysilane (C8-TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) via a two-step catalytic sol-gel process. Due to the favorable chemical reactivity of mercapto pendant moieties, the obtained hybrid monolith was oxidized using hydrogen peroxide (30%, w/w) to yield sulfonic acid groups, which provided strong cation-exchange sites. The obtained hybrid monolith was characterized by diffused infrared spectroscopy, elemental analysis, scanning electron microscopy and mercury intrusion porosimetry. The results show that the resulting monolith contains much higher carbon (31.6%) and sulfur (4.8%) contents than traditionally bonded silica materials. The extraction performance of the hybrid monolith was evaluated using sulfonamides as testing analytes by micro-SPE on-line coupled to HPLC. The results show that the hybrid monolith with hydrophobic and strong cation-exchange functional groups exhibits high extraction efficiency towards the testing analytes. The column-to-column RSD values were 1.3-9.8% for the extraction of SAs investigated. The extraction performance of the hybrid silica monolith remained practically unchanged after treated with acid (pH 1.0) and basic solutions (pH 10.5). Finally, the application of the hybrid monolith was demonstrated by micro-SPE of sulfonamide residues from milk followed by HPLC-UV analysis. The limits of detection (S/N=3) for eight SAs were found to be 1.0-3.0ng/mL in milk. The recoveries of eight SAs spiked in milk sample ranged from 80.2% to 115.6%, with relative standard deviations less than 11.8%.

  7. Enantiomer separation of acidic chiral compounds on a quinine-silica/zirconia hybrid monolith by capillary electrochromatography.

    Science.gov (United States)

    Tran, Le Ngoc; Park, Jung Hag

    2015-05-29

    A weak anion-exchanger chiral selector, quinine-incorporated silica/zirconia hybrid monolithic (QUI-S/ZHM) capillary column was prepared by sol-gel technology. The performance of the QUI-S/ZHM column was investigated for enantioresolution of a set of acidic chiral drugs and dinitrobenzoyl (DNB)-amino acids by capillary electrochromatography in aqueous organic mobile phases composed of acetonitrile (ACN) and triethylammonium acetate (TEAA) buffer. Effects of several parameters including the ACN content, concentration and pH of the mobile phase on the chiral separation were examined. Baseline resolutions of all the compounds were obtained in the mobile phase consisting of 70:30 ACN/TEAA (10mM, pH 6) under applied voltage of -10kV at 25°C within 20min.

  8. Histidine-modified organic-silica hybrid monolithic column for mixed-mode per aqueous and ion-exchange capillary electrochromatography.

    Science.gov (United States)

    Tang, Sheng; Liu, Shujuan; Liang, Xiaojing; Tang, Xiaofen; Wu, Xingcai; Guo, Yong; Liu, Xia; Jiang, Shengxiang

    2015-06-01

    A novel organic-silica hybrid monolith was prepared through the binding of histidine onto the surface of monolithic matrix for mixed-mode per aqueous and ion-exchange capillary electrochromatography. The imidazolium and amino groups on the surface of the monolithic stationary phase were used to generate an anodic electro-osmotic flow as well as to provide electrostatic interaction sites for the charged compounds at low pH. Typical per aqueous chromatographic behavior was observed in water-rich mobile phases. Various polar and hydrophilic analytes were selected to evaluate the characteristics and chromatographic performance of the obtained monolith. Under per aqueous conditions, the mixed-mode mechanism of hydrophobic and ion-exchange interactions was observed and the resultant monolithic column proved to be very versatile for the efficient separations of these polar and hydrophilic compounds (including amides, nucleosides and nucleotide bases, benzoic acid derivatives, and amino acids) in highly aqueous mobile phases. The successful applications suggested that the histidine-modified organic-silica hybrid monolithic column could offer a wide range of retention behaviors and flexible selectivities toward polar and hydrophilic compounds.

  9. One-pot preparation of a mixed-mode organic-silica hybrid monolithic capillary column and its application in determination of endogenous gibberellins in plant tissues.

    Science.gov (United States)

    Zhang, Zheng; Hao, Yan-Hong; Ding, Jun; Xu, Sheng-Nan; Yuan, Bi-Feng; Feng, Yu-Qi

    2015-10-16

    A newly improved one-pot method, based on "thiol-ene" click chemistry and sol-gel approach in microemulsion system, was developed for the preparation of C8/PO(OH)2-silica hybrid monolithic capillary column. The prepared monolith possesses large specific surface area, narrow mesopore size distribution and high column efficiency. The monolithic column was demonstrated to have cation exchange/reversed-phase (CX/RP) mixed-mode retention for analytes on nano-liquid chromatography (nano-LC). On the basis of the developed nano-LC system with MS detector coupled to pipette tip solid phase extraction (PT-SPE) and derivatization process, we then realized simultaneous determination of 10 gibberellins (GAs) with low limits of detection (LODs, 0.003-0.025 ng/mL). Furthermore, 6 endogenous GAs in only 5mg rice leaves (fresh weight) were successfully detected and quantified. The developed PT-SPE-nano-LC-MS strategy may offer promising applications in the determination of low abundant bioactive molecules from complex matrix.

  10. Modified monolithic silica capillary for preconcentration of catecholamines

    Institute of Scientific and Technical Information of China (English)

    Wei Chang; Tusyo-shi Komazu

    2009-01-01

    Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva, the monolithic silica was fabricated in the capillary and the monolithic silica was chemically modified by on-column reaction with phenylboronate. Different modified methods were compared. The concentration conditions were optimized. This study indicates the applicability of the modified monolithic silica capillary when it was used to concentrate catecholamines.

  11. Modified monolithic silica capillary for preconcentration of catecholamines

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva,the monolithic silica was fabricated in the capillary and the monolithic silica was chemically modified by on-column reaction with phenylboronate. Different modified methods were compared. The concentration conditions were optimized. This study indicates the applicability of the modified monolithic sili...

  12. Facile one-pot synthesis of a aptamer-based organic-silica hybrid monolithic capillary column by "thiol-ene" click chemistry for detection of enantiomers of chemotherapeutic anthracyclines.

    Science.gov (United States)

    Jiang, Han-Peng; Zhu, Jiu-Xia; Peng, Chunyan; Gao, Jiajia; Zheng, Fang; Xiao, Yu-Xiu; Feng, Yu-Qi; Yuan, Bi-Feng

    2014-10-07

    In the current study, we developed a facile strategy for the one-pot synthesis of an aptamer-based organic-silica hybrid monolithic capillary column. A 5'-SH-modified aptamer, specifically targeting doxorubicin, was covalently modified in the hybrid silica monolithic column by a sol-gel method combined with "thiol-ene" click reaction. The prepared monolithic column had good stability and permeability, large specific surface, and showed excellent selectivity towards chemotherapeutic anthracyclines of doxorubicin and epirubicin. In addition, the enantiomers of doxorubicin and epirubicin can be easily separated by aptamer-based affinity monolithic capillary liquid chromatography. Furthermore, doxorubicin and epirubicin spiked in serum and urine were also successfully determined, which suggested that the complex biological matrix had a negligible effect on the detection of doxorubicin and epirubicin. Finally, we quantified the concentration of epirubicin in the serum of breast cancer patients treated with epirubicin by intravenous injection. The developed analytical method is cost-effective and rapid, and biological samples can be directly analyzed without any tedious sample pretreatment, which is extremely useful for monitoring medicines in serum and urine for pharmacokinetic studies.

  13. Silica-based polypeptide-monolithic stationary phase for hydrophilic chromatography and chiral separation.

    Science.gov (United States)

    Zhao, Licong; Yang, Limin; Wang, Qiuquan

    2016-05-13

    Glutathione (GSH)-, somatostatin acetate (ST)- and ovomucoid (OV)-functionalized silica-monolithic stationary phases were designed and synthesized for HILIC and chiral separation using capillary electrochromatography (CEC). GSH, ST and OV were covalently incorporated into the silica skeleton via the epoxy ring-opening reaction between their amino groups and the glycidyl moiety in γ-glycidoxypropyltrimethoxysilane (GPTMS) together with polycondensation and copolymerization of tetramethyloxysilane and GPTMS. Not only could the direction and electroosmotic flow magnitude on the prepared GSH-, ST- and OV-silica hybrid monolithic stationary phases be controlled by the pH of the mobile phase, but also a typical HILIC behavior was observed so that the nucleotides and HPLC peptide standard mixture could be baseline separated using an aqueous mobile phase without any acetonitrile during CEC. Moreover, the prepared monolithic columns had a chiral separation ability to separate dl-amino acids. The OV-silica hybrid monolithic column was most effective in chiral separation and could separate dl-glutamic acid (Glu) (the resolution R=1.07), dl-tyrosine (Tyr) (1.57) and dl-histidine (His) (1.06). Importantly, the chiral separation ability of the GSH-silica hybrid monolithic column could be remarkably enhanced when using gold nanoparticles (AuNPs) to fabricate an AuNP-mediated GSH-AuNP-GSH-silica hybrid monolithic column. The R of dl-Glu, dl-Tyr and dl-His reached 1.19, 1.60 and 2.03. This monolithic column was thus applied to separate drug enantiomers, and quantitative separation of all four R/S drug enantiomers were achieved with R ranging from 4.36 to 5.64. These peptide- and protein-silica monolithic stationary phases with typical HILIC separation behavior and chiral separation ability implied their promise for the analysis of not only the future metabolic studies, but also drug enantiomers recognition.

  14. Hierarchically Structured Monolithic ZSM-5 through Macroporous Silica Gel Zeolitization

    Institute of Scientific and Technical Information of China (English)

    Lei Qian; Zhao Tianbo; Li Fengyan; Zong Baoning; Tong Yangchuan

    2006-01-01

    The hierarchically structured ZSM-5 monolith was prepared through transforming the skeletons of the macroporous silica gel into ZSM-5 by the steam-assisted conversion method. The morphology and monolithic shapes of macroporous silica gel were well preserved. The hierarchically structured ZSM-5 monolith exhibited the hierarchical porosity, with mesopores and macropores existing inside the macroporous silica gel, and micropores formed by the ZSM-5. The products have been characterized properly by using the XRD, SEM and N2 adsorption-desorption methods.

  15. Sol-Gel Synthesis of Non-Silica Monolithic Materials

    Directory of Open Access Journals (Sweden)

    Bartłomiej Gaweł

    2010-04-01

    Full Text Available Monolithic materials have become very popular because of various applications, especially within chromatography and catalysis. Large surface areas and multimodal porosities are great advantages for these applications. New sol-gel preparation methods utilizing phase separation or nanocasting have opened the possibility for preparing materials of other oxides than silica. In this review, we present different synthesis methods for inorganic, non-silica monolithic materials. Some examples of application of the materials are also included.

  16. Selective oxidation of cyclohexene through gold functionalized silica monolith microreactors

    Science.gov (United States)

    Alotaibi, Mohammed T.; Taylor, Martin J.; Liu, Dan; Beaumont, Simon K.; Kyriakou, Georgios

    2016-04-01

    Two simple, reproducible methods of preparing evenly distributed Au nanoparticle containing mesoporous silica monoliths are investigated. These Au nanoparticle containing monoliths are subsequently investigated as flow reactors for the selective oxidation of cyclohexene. In the first strategy, the silica monolith was directly impregnated with Au nanoparticles during the formation of the monolith. The second approach was to pre-functionalize the monolith with thiol groups tethered within the silica mesostructure. These can act as evenly distributed anchors for the Au nanoparticles to be incorporated by flowing a Au nanoparticle solution through the thiol functionalized monolith. Both methods led to successfully achieving even distribution of Au nanoparticles along the length of the monolith as demonstrated by ICP-OES. However, the impregnation method led to strong agglomeration of the Au nanoparticles during subsequent heating steps while the thiol anchoring procedure maintained the nanoparticles in the range of 6.8 ± 1.4 nm. Both Au nanoparticle containing monoliths as well as samples with no Au incorporated were tested for the selective oxidation of cyclohexene under constant flow at 30 °C. The Au free materials were found to be catalytically inactive with Au being the minimum necessary requirement for the reaction to proceed. The impregnated Au-containing monolith was found to be less active than the thiol functionalized Au-containing material, attributable to the low metal surface area of the Au nanoparticles. The reaction on the thiol functionalized Au-containing monolith was found to depend strongly on the type of oxidant used: tert-butyl hydroperoxide (TBHP) was more active than H2O2, likely due to the thiol induced hydrophobicity in the monolith.

  17. Polymethacrylate monolithic and hybrid particle-monolithic columns for reversed-phase and hydrophilic interaction capillary liquid chromatography.

    Science.gov (United States)

    Jandera, Pavel; Urban, Jirí; Skeríková, Veronika; Langmaier, Pavel; Kubícková, Romana; Planeta, Josef

    2010-01-01

    We prepared hybrid particle-monolithic polymethacrylate columns for micro-HPLC by in situ polymerization in fused silica capillaries pre-packed with 3-5microm C(18) and aminopropyl silica bonded particles, using polymerization mixtures based on laurylmethacrylate-ethylene dimethacrylate (co)polymers for the reversed-phase (RP) mode and [2-(methacryloyloxy)ethyl]-dimethyl-(3-sulfopropyl) zwitterionic (co)polymers for the hydrophilic interaction (HILIC) mode. The hybrid particle-monolithic columns showed reduced porosity and hold-up volumes, approximately 2-2.5 times lower in comparison to the pure monolithic columns prepared in the whole volume of empty capillaries. The elution volumes of sample compounds are also generally lower in comparison to packed or pure monolithic columns. The efficiency and permeability of the hybrid columns are intermediate in between the properties of the reference pure monolithic and particle-packed columns. The chemistries of the embedded solid particles and of the interparticle monolithic moiety in the hybrid capillary columns contribute to the retention to various degrees, affecting the selectivity of separation. Some hybrid columns provided improved separations of proteins in comparison to the reference particle-packed columns in the reversed-phase mode. Zwitterionic hybrid particle-monolithic columns show dual mode retention HILIC/RP behaviour depending on the composition of the mobile phase and allow separations of polar compounds such as phenolic acids in the HILIC mode at lower concentrations of acetonitrile and, often in shorter analysis time in comparison to particle-packed and full-volume monolithic columns.

  18. Monolithic stationary phases with incorporated fumed silica nanoparticles. Part II. Polymethacrylate-based monolithic column with "covalently" incorporated modified octadecyl fumed silica nanoparticles for reversed-phase chromatography.

    Science.gov (United States)

    Aydoğan, Cemil; El Rassi, Ziad

    2016-05-01

    This study is concerned with the incorporation of surface modified fumed silica nanoparticles (FSNPs) into polymethacrylate based monolithic columns for use in reversed phase chromatography (RPC) of small solutes and proteins. First, FSNPs were modified with 3-(trimethoxysilyl)propylmethacrylate (TMSPM) to yield the "hybrid" methacryloyl fumed silica nanoparticle (MFSNP) monomer. The resulting MFSNP was then mixed with glyceryl monomethacrylate (GMM) and ethylene dimethacrylate (EDMA) in a binary porogenic solvent composed of cyclohexanol and dodecanol, and the in situ copolymerization of MFSNP, GMM and EDMA was performed in a stainless steel column of 4.6 mm i.d. The silanol groups of the hybrid monolith thus obtained were grafted with octadecyl ligands by perfusing the hybrid monolithic column with a solution of 4% w/v of dimethyloctadecylchlorosilane (DODCS) in toluene while the column was maintained at 110°C for 6h (in a heated HPLC oven). One of the originalities of this study was to demonstrate MFSNP as a novel derivatized "hybrid monomer" in making RPC monolithic columns with surface bound octadecyl ligands. In this respect, the RPC behavior of the monolithic column with "covalently" incorporated FNSPs having surface grafted octadecyl ligands was evaluated with alkylbenzenes, aniline derivatives and phenolic compounds. The results showed that the hybrid poly(GMA-EDMA-MFSNP) having surface bound octadecyl ligands exhibited hydrophobic interactions under reversed phase elution conditions. Furthermore, six standard proteins were baseline separated on the column using a 10min linear gradient elution at increasing ACN concentration in the mobile phase at a flow rate of 1.0mL/min using a 10 cm×4.6mm i.d. column. The relative standard deviations (RSDs) for the retention times of the tested solutes were lower than 2.1% and 2.4% under isocratic elution and gradient elution conditions, respectively.

  19. Structure and properties of hybrid poly(2-hydroxyethyl methacrylate)/SiO2 monoliths

    DEFF Research Database (Denmark)

    Ji, Xiangling; Jiang, Shichun; Qiu, Xuepeng

    2003-01-01

    Abstract: Hybrid poly(2-hydroxyethyl methacrylate) (PHEMA)/SiO2 monoliths were synthesized via a sol-gel process of the precursor tetraethyl orthosilicate (TEOS) and the in situ free-radical polymerization of 2-hydroxyethyl methacrylate (HEMA). The weight ratio of the starting chemicals, TEOS to ...... related to some degree of chemical crosslinking between the polymer and the silica moiety, which would greatly improve the thermal stability of such hybrid monoliths compared with a pure PHEMA....

  20. Preparation and applications of hybrid organic-inorganic monoliths: a review.

    Science.gov (United States)

    Zhu, Tao; Row, Kyung Ho

    2012-06-01

    This review presents an overview of the properties of hybrid organic-inorganic monolithic materials and summarizes the recent developments in the preparation and applications of these hybrid monolithic materials. Hybrid monolithic materials with porosities, surface functionalities, and fast dynamic transport have developed rapidly, and have been used in a wide range of applications owing to the low cost, good stability, and excellent performance. Basically, these materials can be divided into two major types according to the chemical composition: hybrid silica-based monolith (HSM) and hybrid polymer-based monolith (HPM). Compared to the HPM, HSM monolith has been attracting most wide attentions, and it is commonly synthesized by the sol-gel process. The conventional preparation procedures of two type's hybrid organic-inorganic monoliths are addressed. Applications of hybrid organic-inorganic monoliths in optical devices, capillary microextraction (CME), capillary electrochromatography (CEC), high performance liquid chromatography (HPLC), and chiral separation are also reviewed. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Structure and properties of hybrid poly(2-hydroxyethyl methacrylate)/SiO2 monoliths

    DEFF Research Database (Denmark)

    Ji, Xiangling; Jiang, Shichun; Qiu, Xuepeng

    2003-01-01

    to HEMA, was varied between 100/0 and 0/100. Structural analysis was performed by IR and NMR. The NMR results indicated that the introduction of PHEMA in the silica networks gave rise to a lower degree of condensation of TEOS. The resulting monoliths showed more than 75% transmittance in the visible...... related to some degree of chemical crosslinking between the polymer and the silica moiety, which would greatly improve the thermal stability of such hybrid monoliths compared with a pure PHEMA....

  2. Monolithic Silica aerogel in superinsulating glazings

    DEFF Research Database (Denmark)

    Duer, Karsten; Svendsen, Sv Aa Højgaard

    1988-01-01

    Silica aerogel is an open-pored porous transparent material with optical and thermal properties that makes the material very interesting as an insulation material in windows. A number of different aerogels have been investigated for their optical and thermal performance. High thermal resistance....... This phenomenon is considered being the main obstacle to incorporate the material in clear glazings but a significant improvement of the optical quality of aerogel has been observed during the last five years. A number of prototypical evacuated 500x500x28 mm aerogel double glazed units employing a new edge seal...

  3. The Advanced Virgo monolithic fused silica suspension

    Energy Technology Data Exchange (ETDEWEB)

    Aisa, D.; Aisa, S.; Campeggi, C.; Colombini, M. [University of Perugia and INFN Perugia (Italy); Conte, A. [University of Roma Sapienza and INFN Roma (Italy); Farnesini, L. [University of Perugia and INFN Perugia (Italy); Majorana, E.; Mezzani, F. [University of Roma Sapienza and INFN Roma (Italy); Montani, M. [University of Urbino and INFN Firenze (Italy); Naticchioni, L.; Perciballi, M. [University of Roma Sapienza and INFN Roma (Italy); Piergiovanni, F. [University of Urbino and INFN Firenze (Italy); Piluso, A. [University of Perugia and INFN Perugia (Italy); Puppo, P., E-mail: paola.puppo@roma1.infn.it [University of Roma Sapienza and INFN Roma (Italy); Rapagnani, P. [University of Roma Sapienza and INFN Roma (Italy); Travasso, F. [University of Perugia and INFN Perugia (Italy); Vicerè, A. [University of Urbino and INFN Firenze (Italy); Vocca, H. [University of Perugia and INFN Perugia (Italy)

    2016-07-11

    The detection of gravitational waves is one of the most challenging prospects faced by experimental physicists. Suspension thermal noise is an important noise source at operating frequencies between approximately 10 and 30 Hz, and represents a limit to the sensitivity of the ground based interferometric gravitational wave detectors. Its effects can be reduced by minimizing the losses and by optimizing the geometry of the suspension fiber as well as its attachment system. In this proceeding we will describe the mirrors double stage monolithic suspension system to be used in the Advanced Virgo (AdV) detector. We also present the results of the thermal noise study, performed with the help of a finite elements model, taking into account the precise geometry of the fibers attachment systems on the suspension elements. We shall demonstrate the suitability of this suspension for installation in AdV. - Highlights: • Suspension system design for the test masses of the gravitational wave detectors. • Finite element model studies. • Suspension thermal noise studies.

  4. Preparing silica aerogel monoliths via a rapid supercritical extraction method.

    Science.gov (United States)

    Carroll, Mary K; Anderson, Ann M; Gorka, Caroline A

    2014-02-28

    A procedure for the fabrication of monolithic silica aerogels in eight hours or less via a rapid supercritical extraction process is described. The procedure requires 15-20 min of preparation time, during which a liquid precursor mixture is prepared and poured into wells of a metal mold that is placed between the platens of a hydraulic hot press, followed by several hours of processing within the hot press. The precursor solution consists of a 1.0:12.0:3.6:3.5 x 10(-3) molar ratio of tetramethylorthosilicate (TMOS):methanol:water:ammonia. In each well of the mold, a porous silica sol-gel matrix forms. As the temperature of the mold and its contents is increased, the pressure within the mold rises. After the temperature/pressure conditions surpass the supercritical point for the solvent within the pores of the matrix (in this case, a methanol/water mixture), the supercritical fluid is released, and monolithic aerogel remains within the wells of the mold. With the mold used in this procedure, cylindrical monoliths of 2.2 cm diameter and 1.9 cm height are produced. Aerogels formed by this rapid method have comparable properties (low bulk and skeletal density, high surface area, mesoporous morphology) to those prepared by other methods that involve either additional reaction steps or solvent extractions (lengthier processes that generate more chemical waste).The rapid supercritical extraction method can also be applied to the fabrication of aerogels based on other precursor recipes.

  5. Preparation and evaluation of micro and meso porous silica monoliths with embedded carbon nanoparticles for the extraction of non-polar compounds from waters.

    Science.gov (United States)

    Fresco-Cala, Beatriz; Cárdenas, Soledad; Valcárcel, Miguel

    2016-10-14

    A novel hybrid micro and meso porous silica monolith with embedded carbon nanoparticles (Si-CNPs monolith) was prepared inside a fused silica capillary (3cm in length) and used as a sorbent for solid-phase microextraction. The hybrid monolithic capillary was synthetized by hydrolysis and polycondensation of a mixture of tetraethoxysilane (TEOS), ethanol, and three different carbon nanoparticles such as carboxylated single-walled carbon nanotubes (c-SWCNTs), carboxylated multi-walled carbon nanotubes (c-MWCNTs), and oxidized single-walled carbon nanohorns (o-SWNHs) via a two-step catalytic sol-gel process. Compared with silica monolith without carbon nanoparticles, the developed monolithic capillary column exhibited a higher extraction efficiency towards the analytes which can be ascribed to the presence of the carbon nanoparticles. In this regard, the best performance was achieved for silica monolith with embedded c-MWCNTs. The resulted monolithic capillaries were also characterized by scanning electron microscopy (SEM), elemental analysis and nitrogen intrusion porosimetry. Variables affecting to the preparation of the sorbent phase including three different carbon nanoparticles and extraction parameters were studied in depth using polycyclic aromatic hydrocarbons (PAHs) as target analytes. Gas chromatography-mass spectrometry was selected as instrumental technique. Detection limits range from 0.1 to 0.3μgL(-1), and the inter-extraction units precision (expressed as relative standard deviation) is between 5.9 and 14.4%.

  6. Monolithic silica aerogel - material design on the nano-scale

    DEFF Research Database (Denmark)

    Jensen, Karsten Ingerslev; Schultz, Jørgen Munthe; Kristiansen, Finn Harken

    By means of a production process in two major steps - a sol/gel process and a supercritical drying – open-cell, monolithic silica aerogel can be made. This material can have a density in the range of 30- to 300 kg/m3, corresponding to porosities between 86 and 98 %. The solid structure has...... of piezoelectric transducers. - Other applications could be; waste encapsulation, spacers for vacuum insulation panels, membranes, etc. Department of Civil Engineering is co-ordinator of a current EU FP5 research project1, which deals with the application of aerogel as transparent insulation materials in windows....... Due to the excellent optical and thermal properties of aerogel, it is possible to develop windows with both high insulation and high transmittance, which is impossible applying the conventional window techniques, i.e. extra layers of glass, low-e coatings and gas fillings. It can be shown...

  7. Preparation and evaluation of a novel hybrid monolithic column based on pentafluorobenzyl imidazolium bromide ionic liquid.

    Science.gov (United States)

    Shan, Yuanhong; Qiao, Lizhen; Shi, Xianzhe; Xu, Guowang

    2015-01-02

    To develop a novel hybrid monolithic column based on pentafluorobenzyl imidazolium bromide ionic liquid, a new ionic liquid monomer was synthesized from 1-vinylimidazole and pentafluorobenzyl bromide. By employing a facile one-step copolymerization of polyhedral-oligomeric-silsesquioxane-type (POSS) cross-linking agent and the home-made ionic liquid monomer, the hybrid monolithic columns were in situ fabricated in fused-silica capillary. The morphology of monolithic column was characterized by scanning electron microscope (SEM) and the chemical composition was confirmed by Fourier-transform infrared spectroscopy (FT-IR) and elemental analysis. Excellent mechanical stability and slight swelling propensity were exhibited which was ascribed to the rigid hybrid monolithic skeleton. Reproducibility results of run-to-run, column-to-column, batch-to-batch and day-to-day were investigated and the RSDs were less than 0.46%, 1.84%, 3.96% and 3.17%, respectively. The mixed-mode retention mechanism with hydrophobic interaction, π-π stacking, ion-exchange, electrostatic interaction and dipole-dipole interaction was explored systematically using analytes with different structure types. Satisfied separation capability and column efficiency were achieved for the analysis of small molecular compounds such as alkylbenzenes, polycyclic aromatic hydrocarbons, nucleosides and halogenated compounds. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Feasibility of the preparation of silica monoliths for gas chromatography: fast separation of light hydrocarbons.

    Science.gov (United States)

    Azzouz, Imadeddine; Essoussi, Anouar; Fleury, Joachim; Haudebourg, Raphael; Thiebaut, Didier; Vial, Jerome

    2015-02-27

    The preparation conditions of silica monoliths for gas chromatography were investigated. Silica-based monolithic capillary columns based on sol-gel process were tested in the course of high-speed gas chromatographic separations of light hydrocarbons mixture (C1-C4). The impact of modifying the amount of porogen and/or catalyst on the monolith properties were studied. At the best precursor/catalyst/porogen ratio evaluated, a column efficiency of about 6500 theoretical plates per meter was reached with a very good resolution (4.3) for very light compounds (C1-C2). The test mixture was baseline separated on a 70cm column. To our knowledge for the first time a silica-based monolithic capillary column was able to separate light hydrocarbons from methane to n-butane at room temperature with a back pressure in the range of gas chromatography facilities (under 4.1bar).

  9. Effect of Silica on High-Temperature Interfacial Phenomena of Monolithic Refractories with Al Alloy

    Science.gov (United States)

    Koshy, Pramod; Gupta, Sushil; Sahajwalla, Veena; Edwards, Phil

    2008-04-01

    An experimental study was conducted to study the interfacial phenomena between monolithic refractories and Al alloy at 1250 °C. Dynamic contact angles of monolithic substrates with varying silica levels were measured using the sessile drop technique, while phases present in the preheated monolithic samples and interfacial reaction products were characterized using X-ray diffraction (XRD) and an electron probe microanalyzer (EPMA). The contact angles in the Al alloy/silica system were found to change much more rapidly as compared to that of the alloy/alumina system, clearly demonstrating the high wetting tendency of silica. Under the tested conditions, the corundum phase forms at the interface while Mg was found to vaporize from the alloy and accumulate at the bottom of the monolithic substrate. Both these phenomena are shown to influence the intensity of contact angle variations with time and, thereby, the wetting behavior of monolithic substrates. Based on dynamic contact angles and equilibrium calculations, monolithic refractories are further classified into three groups, such that the wetting characteristics of those with compositions in the ranges of 0 to 25 pct, 25 to 45 pct, and >45 pct silica were shown to be dictated by the presence of corundum, mullite, and free silica, respectively, as the predominant phase.

  10. Chromatographic comparison of bupivacaine imprinted polymers prepared in crushed monolith, microsphere, silica-based composite and capillary monolith formats.

    Science.gov (United States)

    Oxelbark, Joakim; Legido-Quigley, Cristina; Aureliano, Carla S A; Titirici, Maria-Magdalena; Schillinger, Eric; Sellergren, Börje; Courtois, Julien; Irgum, Knut; Dambies, Laurent; Cormack, Peter A G; Sherrington, David C; De Lorenzi, Ersilia

    2007-08-10

    A comprehensive comparison of five chromatographic stationary phases based on molecularly imprinted polymers is presented. Efficiency, imprinting factors, water compatibility and batch-to-batch reproducibility are discussed for crushed monolith, microspheres, two silica-based composites and capillary monoliths, all imprinted with the local anaesthetic bupivacaine. Synthesis protocol and chromatographic test conditions have been kept fixed within certain limits, in order to provide further insight into the strengths and weaknesses of the different formats. Excluding microparticles, all formats give satisfactory performance, especially in aqueous mobile phases. An assessment of batch-to-batch reproducibility in different mobile phases adds further value to this comparison study.

  11. Development and Investigation of Evacuated Windows Based on Monolithic Silica Xerogel Spacers

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Svendsen, Sv Aa Højgaard

    The objective of the project is to develop and investigate insulating glazings based on evacuated monolithic silica xerogel spacers. Since the starting date January 1, 1994 the project has been closely connected to the parallel project "Development and Investigation of Evacuated Windows based...... will be approximately 0.013 W/(m K) which is approximately 33% of the value for commonly used insulation materials, e.g. mineral wool. Monolithic silica xerogel is a highly porous material (pore volume up to 90%) with a solar transmittance of 50% (thickness = 20 mm). However, if the silica xerogel is not made...... and 3) application for insulating glazings.Scientific developments have made it possible to prepare low density monolithic silica xerogels, only from about 1990, and developments in both the production process as well as size of the samples are necessary for a commercial use of the material...

  12. Design and evaluation of synthetic silica-based monolithic materials in shrinkable tube for efficient protein extraction.

    Science.gov (United States)

    Alzahrani, Eman; Welham, Kevin

    2011-10-21

    Sample pretreatment is a required step in proteomics in order to remove interferences and preconcentrate the samples. Much research in recent years has focused on porous monolithic materials since they are highly permeable to liquid flow and show high mass transport compared with more common packed beds. These features are due to the micro-structure within the monolithic silica column which contains both macropores that reduce the back pressure, and mesopores that give good interaction with analytes. The aim of this work was to fabricate a continuous porous silica monolithic rod inside a heat shrinkable tube and to compare this with the same material whose surface has been modified with a C(18) phase, in order to use them for preconcentration/extraction of proteins. The performance of the silica-based monolithic rod was evaluated using eight proteins; insulin, cytochrome C, lysozyme, myoglobin, β-lactoglobulin, ovalbumin, hemoglobin, and bovine serum albumin at a concentration of 60 μM. The results show that recovery of the proteins was achieved by both columns with variable yields; however, the C(18) modified silica monolith gave higher recoveries (92.7 to 109.7%) than the non-modified silica monolith (25.5 to 97.9%). Both silica monoliths can be used with very low back pressure indicating a promising approach for future fabrication of the silica monolith inside a microfluidic device for the extraction of proteins from biological media.

  13. Extraction of genomic DNA using a new amino silica monolithic column.

    Science.gov (United States)

    Liu, Lijia; Yu, Shengbing; Yang, Shuixian; Zhou, Ping; Hu, Jiming; Zhang, Yibing

    2009-08-01

    A new amino silica monolithic column was developed for DNA extraction in a miniaturized format. The monolithic column was prepared in situ by polymerization of tetraethoxysilane (TEOS) and N-(beta-aminoethyl)-gamma-aminopropylmethyldimethoxysilane (AEAPMDMS). DNA was loaded in 50 mM tris(hydroxylmethyl)aminomethane-EDTA buffer at pH 7.0 and eluted with 300 mM potassium phosphate solution at pH 10.0. Under optimal condition, a 6.0-cm monolithic column provided a capacity of 56 ng DNA with an extraction efficiency of 71 +/- 5.2% (X +/- RSD). When the amino silica monolithic column was applied to extract genomic DNA from the whole blood of crucian carp, an extraction efficiency of 52 +/- 5.6% (X +/- RSD) was obtained by three extractions. Since the chaotropic-based sample loading and organic solvent wash steps were avoided in this procedure, the purified DNA was suitable for downstream processes such as PCR. This amino silica monolithic column was demonstrated to allow rapid and efficient DNA purification in microscale.

  14. Comparison of various silica-based monoliths for the analysis of large biomolecules.

    Science.gov (United States)

    Vuignier, Karine; Fekete, Szabolcs; Carrupt, Pierre-Alain; Veuthey, Jean-Luc; Guillarme, Davy

    2013-07-01

    In the present study, three types of silica-based monoliths, i.e. the first and second generations of commercial silica monolithic columns and a wide-pore prototype monolith were compared for the analysis of large biomolecules. These molecules possess molecular weights between 1 and 66 kDa. The gradient kinetic performance of the first-generation monolith was lower than that of the second generation, for large biomolecules (>14 kDa) but very close with smaller ones (1.3-5.8 kDa). In contrast, the wide-pore prototype column was particularly attractive with proteins larger than 19 kDa (higher peak capacity). Among these three columns, the selectivity and retention remained quite similar but a possible larger number of accessible and charged residual silanols was noticed on the wide-pore prototype material, which led to unpredicted small changes in selectivity and slightly broader peaks than expected. The peak shapes attained with the addition of 0.1% formic acid in the mobile phase remained acceptable for MS coupling, particularly for biomolecules of less than 6 kDa. It was found that one of the major issues with all of these silica-based monoliths is the possible poor recovery of large biomolecules (principally with monoclonal antibody fragments of more than 25 kDa).

  15. Continuous-Flow Monolithic Silica Microreactors with Arenesulphonic Acid Groups: Structure–Catalytic Activity Relationships

    Directory of Open Access Journals (Sweden)

    Agnieszka Ciemięga

    2017-08-01

    Full Text Available The performance of monolithic silica microreactors activated with sulphonic acid groups and a packed bed reactor with Amberlyst 15 resin were compared in the esterification of acetic acid with n-butanol. The monolithic microreactors were made of single silica rods with complex pore architecture, differing in the size of mesopores, and in particular, flow-through macropores which significantly affected the flow characteristic of the continuous system. The highest ester productivity of 105.2 mol·molH+−1·h−1 was achieved in microreactor M1 with the largest porosity, characterized by a total pore volume of 4 cm3·g−1, mesopores with 20 nm diameter, and large flow-through macropores 30–50 μm in size. The strong impact of the permeability of the monoliths on a reaction kinetics was shown.

  16. Monolithic stationary phases with incorporated fumed silica nanoparticles. Part I. Polymethacrylate-based monolithic column with incorporated bare fumed silica nanoparticles for hydrophilic interaction liquid chromatography.

    Science.gov (United States)

    Aydoğan, Cemil; El Rassi, Ziad

    2016-05-01

    Fumed silica nanoparticles (FSNPs), were incorporated for the first time into a polymethacrylate monolithic column containing glyceryl monomethacrylate (GMM) and ethylene dimethacrylate (EDMA) in order to develop a new monolithic column for hydrophilic interaction high performance liquid chromatography (HILIC). When compared to poly(GMM-EDMA) monolithic column without FSNPs, the same monolithic column with incorporated FSNPs yielded important effects on HILIC separations. The effects of monomers and FSNPs content of the polymerization mixture on the performance of the monolithic column were examined in details, and the optimized stationary phase was investigated over a wide range of mobile phase composition with polar acidic, weakly basic and neutral analytes including hydroxy benzoic acids, nucleotides, nucleosides, dimethylformamide, formamide and thiourea. The retention of these analytes was mainly controlled by hydrophilic interactions with the FSNPs and electrostatic repulsion from the negatively charged silica surface in the case of hydroxy benzoic acids and nucleotides. The electrostatic repulsion was minimized by decreasing the pH of the aqueous component of the mobile phase, which in turn enhanced the retention of acidic solutes. Nucleotides were best separated using step gradient elution at decreasing pH as well as ACN concentration in the mobile phase. Improved peak shape and faster analysis of nucleosides were attained by a fast linear gradient elution with a shallow decrease in the ACN content of the ACN-rich mobile phase. The run-to-run and column-to-column reproducibility were satisfactory. The percent relative standard deviations (%RSDs) for the retention times of tested solutes were lower than 2.5% under isocratic conditions and lower than 3.5 under gradient conditions.

  17. Recycle Adsorption of Cu2+ on Amine-functionalized Mesoporous Silica Monolithic

    Institute of Scientific and Technical Information of China (English)

    ZHAO Da-zhou; JING Shu-bo; XU Jia-ning; YANG Hong; ZHENG Wei; SONG Tian-you; ZHANG Ping

    2013-01-01

    3-Aminopropyltriethoxysilane functionalized worm-like mesoporous silica monolithic(WMSM-NH2) was prepared and used as a new regenerable adsorbent for the removal of Cu2+ ions.The analysis results show that the WMSM-NH2 monolithic had a high efficiency value of 99.3% for Cu2+ remediation when the Cu2+ solution was at an initial concentration of 10.32 mg/L.The regeneration study of the WMSM-NH2 monolithic presented that the adsorption efficiency of 89.0% was remained and a mass of 92.0% was left after seven adsorption-desorption cycles were executed.The monolithic material with high resistance to the acid and good mechanical stability can facilitate the operations of adsorption and regeneration of the adsorbent.

  18. Development and Investigation of Evacuated Windows Based on Monolithic Silica Xerogel Spacers

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Svendsen, Sv Aa Højgaard

    will be approximately 0.013 W/(m K) which is approximately 33% of the value for commonly used insulation materials, e.g. mineral wool. Monolithic silica xerogel is a highly porous material (pore volume up to 90%) with a solar transmittance of 50% (thickness = 20 mm). However, if the silica xerogel is not made...... and 3) application for insulating glazings.Scientific developments have made it possible to prepare low density monolithic silica xerogels, only from about 1990, and developments in both the production process as well as size of the samples are necessary for a commercial use of the material...... for insulating glazings. Using the material as spacer between two layers of glass with a vacuum tight sealing of the rim combined with an internal gas pressure below 50-100 hPa result in an insulating glazing having a heat loss coefficient comparable with that of the surrounding walls, but at the same time...

  19. Hybrid and monolithic integration of planar lightwave circuits (PLCs)

    Science.gov (United States)

    Chen, Ray T.

    2008-02-01

    In this paper, we review the status of monolithic and hybrid integration of planar lightwave circuits (PLCs). Building blocks needed for system integration based on polymeric materials, III-V semiconductor materials, LiNbO 3 and SOI on Silicon are summarized with pros and cons. Due to the maturity of silicon CMOS technology, silicon becomes the platform of choice for optical application specific integrated circuits (OASICs). However, the indirect bandgap of silicon makes the formation of electrically pumped silicon laser a remote plausibility which requires hybrid integration of laser sources made out of III-V compound semicouductor.

  20. Biodiesel production by using lipase immobilized onto novel silica-based hybrid foams

    Energy Technology Data Exchange (ETDEWEB)

    Brun, Nicolas [Centre de Recherche Paul Pascal, Pessac (France); Institut des Sciences Moleculaires, Talence (France); Garcia, Annick Babeau; Oestreicher, Victor; Durand, Fabien; Backov, Renal [Centre de Recherche Paul Pascal, Pessac (France); Deleuze, Herve [Institut des Sciences Moleculaires, Talence (France); Laurent, Guillaume; Sanchez, Clement [Laboratoire de Chimie de la Matiere Condensee, Paris (France)

    2010-07-01

    The covalent immobilization of crude lipases within silica-based macroporous frameworks have been performed by combining sol-gel process, concentrated direct emulsion, lyotropic mesophase and post-synthesis functionalizations. The assynthesized open cell hybrid monoliths exhibit high macroscopic porosity, around 90%, providing interconnected scaffold while reducing the diffusion low kinetic issue. The entrapment of enzymes in such foams deals with a high stability over esterification of fatty acids, hydrolysis of triglycerides (not shown herein) and biodiesel production by transesterification. (orig.)

  1. Metal doped hybrid silica membranes for separation

    NARCIS (Netherlands)

    Ru, Yanfei

    2014-01-01

    The present study describes the e ect of di erent factors such as the type of dopants and the percentage of dopants on the stability and permeance of membranes. Di erent dopants such as zirconia, yttrium were used to produce organic-inorganic hybrid silica membranes. During the programme, zirconia d

  2. Synthesis and Textural Characterization of Mesoporous and Meso-/Macroporous Silica Monoliths Obtained by Spinodal Decomposition

    Directory of Open Access Journals (Sweden)

    Anne Galarneau

    2016-04-01

    Full Text Available Silica monoliths featuring either mesopores or flow-through macropores and mesopores in their skeleton are prepared by combining spinodal phase separation and sol-gel condensation. The macroporous network is first generated by phase separation in acidic medium in the presence of polyethyleneoxides while mesoporosity is engineered in a second step in alkaline medium, possibly in the presence of alkylammonium cations as surfactants. The mesoporous monoliths, also referred as aerogels, are obtained in the presence of alkylpolyethylene oxides in acidic medium without the use of supercritical drying. The impact of the experimental conditions on pore architecture of the monoliths regarding the shape, the ordering, the size and the connectivity of the mesopores is comprehensively discussed based on a critical appraisal of the different models used for textural analysis.

  3. [Reparation and application of perfluorodecyl modified silica monolithic capillary column in extraction and enrichment of perfluorooctane sulfonates].

    Science.gov (United States)

    Huang, Ke; Zhou, Naiyuan; Chen, Bo

    2011-10-01

    A perfluorodecyl modified silica monolithic capillary column has been prepared by using sol-gel method. The preparation steps included hydrolysis of alkoxy silane, fasculation of silanol, gelation, aging, meso-pore preparation, drying and surface modification. It could be used as a solid phase extraction (SPE) microcolumn for extraction and enrichment of perfluorooctane sulfonate (PFOS). The enrichment characteristics and efficiency of the perfluorodecyl modified monolithic silica capillary column has been investigated and compared with C18 silica monolithic capillary column. The results indicated that the perfluorodecyl modified silica monolithic capillary column ( 15 cm x 75 microm) had a higher adsorption capacity and a better enrichment selectivity for PFOS. The average adsorption capacity of the perfluorodecyl modified silica monolithic capillary column was 75 ng. And when the PFOS mass concentration in sample was 0. 25 mg/L, the enrichment factor was 29-fold in average. Owing to the good performance of the perfluorodecyl modified silica monolithic capillary column, it can be used for the extraction and enrichment of trace PFOS in water to meet the requirements of water quality monitoring and analysis.

  4. Chitosan-Silica Hybrid Porous Membranes

    OpenAIRE

    Pandis, C.; S. Madeira; Matos, J.,; Kyritsis, A.; Mano, J. F.; Ribelles, J.L. Gómez

    2014-01-01

    Chitosan–silica porous hybrids were prepared by a novel strategy in order to improve the mechanical properties of chitosan (CHT) in the hydrogel state. The inorganic silica phase was introduced by sol–gel reactions in acidic medium inside the pores of already prepared porous scaffolds. In order to make the scaffolds insoluble in acidic media chitosan was cross-linked by genipin (GEN) with an optimum GEN concentration of 3.2 wt.%. Sol–gel reactions took place with Tetraethylorthosilicate (TEOS...

  5. Synthesis of silica aerogel monoliths with controlled specific surface areas and pore sizes

    Science.gov (United States)

    Gao, Bingying; Lu, Shaoxiang; Kalulu, Mulenga; Oderinde, Olayinka; Ren, Lili

    2017-07-01

    To replace traditional preparation methods of silica aerogels, a small-molecule 1,2-epoxypropane (PO) has been introduced into the preparation process instead of using ammonia as the cross-linking agent, thus generating a lightweight, high porosity, and large surface area silica aerogel monolithic. We put forward a simple solution route for the chemical synthesis of silica aerogels, which was characterized by scanning electron microscopy (SEM), TEM, XRD, FTIR, thermogravimetric analysis (TGA) and the Brunauer-Emmett-Teller (BET) method In this paper, the effect of the amount of PO on the microstructure of silica aerogels is discussed. The BET surface areas and pore sizes of the resulting silica aerogels can be freely adjusted by changing the amount of PO, which will be helpful in promoting the development of silica aerogels to fabricate other porous materials with similar requirements. We also adopted a new organic solvent sublimation drying (OSSD) method to replace traditional expensive and dangerous drying methods such as critical point drying and freeze drying. This simple approach is easy to operate and has good repeatability, which will further facilitate actual applications of silica aerogels.

  6. On-chip generation and demultiplexing of quantum correlated photons using a silicon-silica monolithic photonic integration platform.

    Science.gov (United States)

    Matsuda, Nobuyuki; Karkus, Peter; Nishi, Hidetaka; Tsuchizawa, Tai; Munro, William J; Takesue, Hiroki; Yamada, Koji

    2014-09-22

    We demonstrate the generation and demultiplexing of quantum correlated photons on a monolithic photonic chip composed of silicon and silica-based waveguides. Photon pairs generated in a nonlinear silicon waveguide are successfully separated into two optical channels of an arrayed-waveguide grating fabricated on a silica-based waveguide platform.

  7. Efficient application of monolithic silica column to determination of illicit heroin street sample by HPLC.

    Science.gov (United States)

    Macchia, Marco; Bertini, Simone; Mori, Claudio; Orlando, Caterina; Papi, Chiara; Placanica, Giorgio

    2004-03-01

    In this paper, an HPLC method is proposed for a routine, rapid and simple analysis of heroin samples confiscated from the illicit market, based on a new type of packing for HPLC columns (monolithic silica). Acetonitrile and pH 3.5 phosphate buffer solution were used under both isocratic and gradient conditions. Under our analytical conditions, all the components of a typical mixture of an illicit heroin sample proved to be fully separated into well-resolved peaks in 7 min. Analytical linearity and accuracy of the method were also studied for all analytes using tetracaine hydrochloride as the internal standard.

  8. Solvothermal removal of the organic template from L{sub 3} ('sponge') templated silica monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Dabbs, Daniel M. [Princeton University, Department of Chemical Engineering (United States); Mulders, Norbert [University of Delaware, Department of Physics and Astronomy (United States); Aksay, Ilhan A. [Princeton University, Department of Chemical Engineering (United States)], E-mail: iaksay@princeton.EDU

    2006-10-15

    We compare the methods of continuous solvent (Soxhlet) and supercritical solvent extractions for the removal of the organic template from nanostructured silica monoliths. Our monoliths are formed by templating the L{sub 3} liquid crystal phase of cetylpyridinium chloride in aqueous solutions with tetramethoxy silane. The monoliths that result from both Soxhlet and supercritical extraction methods are mechanically robust, optically clear, and free of cracks. The Soxhlet method compares favorably with supercritical solvent extraction in that equivalent L{sub 3}-templated silica can be synthesized without the use of specialized reactor hardware or higher temperatures and high pressures, while avoiding noxious byproducts. The comparative effectiveness of various solvents in the Soxhlet process is related to the Hildebrand solubility parameter, determined by the effective surface area of the extracted silica.

  9. Synthesis of Mesoporous Silica Monoliths — A Novel Approach Towards Fabrication of Solid-State Optical Sensors for Environmental Applications

    Science.gov (United States)

    Prabhakaran, D.; Subashini, C.; Akhila Maheswari, M.

    2016-10-01

    Mesoporous silica monoliths are an attractive area of research owing to their high specific surface area, uniform channels and mesoporous size (2-30nm). This paper deals with the direct templating synthesis of a mesoporous worm-like silica monolithic material using F127 — a triblock copolymer, by micro-emulsion technique using trimethyl benzene (TMB), as the solvent. The synthesized silica monolith is characterized using SEM-EDAX, XRD, BET, NMR and FT-IR. The monolith shows an ordered worm-like mesoporous structure with tuneable through pores, an excellent host for the anchoring of chromo-ionophores for the naked-eye metal ion-sensing. The mesoporous monoliths were loaded with 4-dodecyl-6-(2-pyridylazo)-phenol (DPAP) ligand through direct immobilization, thereby acting as solid-state naked-eye colorimetric ion-sensors for the sensing toxic Pb(II) ions at parts-per-billion (ppb) level in various industrial and environmental systems. The influence of various experimental parameters such as solution pH, limiting ligand loading concentration, amount of monolith material, matrix tolerance level, limit of detection and quantification has been studied and optimized.

  10. Fast HPLC for quality control of Harpagophytum procumbens by using a monolithic silica column: method transfer from conventional particle-based silica column.

    Science.gov (United States)

    Schmidt, Alexander H

    2005-05-06

    The applicability of a monolithic C18-bonded silica column for the rapid HPLC separation of ingredients in medicinal plants and their phytopharmaceutical preparations has been evaluated in the author's laboratory. In this presentation, an existing method for the determination of the iridoid glycoside harpagoside in Harpagophytum procumbens (Devil's Claw) was successfully transferred from a conventional particle-based C18 silica column to a monolithic silica column. The very high porosity of the stationary phase allows chromatography with a much lower backpressure than on conventional columns. Therefore, the flow rate could be easily increased from 0.8 mL/min (particle-based column) to 5 mL/min (monolithic column) and the run-time reduced from 30 to 5 min (that is a reduction about 85% !), without losing any chromatographic resolution of the compound of interest. The amount of harpagoside was measured with the original method on a conventional particle-based silica column and on the adapted method on a monolithic silica column. The statistical mean t-test showed no significant differences of the variances and the means indicating that the fast HPLC method is an acceptable alternative. The shorter analysis time makes the method very valuable for commercial quality control of Harpagophytum extracts and its pharmaceutical preparations.

  11. Photopolymerization of acrylamide as a new functionalization way of silica monoliths for hydrophilic interaction chromatography and coated silica capillaries for capillary electrophoresis.

    Science.gov (United States)

    El-Debs, R; Marechal, A; Dugas, V; Demesmay, C

    2014-01-24

    A simple, rapid and localizable photochemical process for the preparation of hydrophilic coated capillary and silica-based monolithic capillary columns is described. The process involves the free radical polymerization of acrylamide monomers onto acrylate pre-activated silica surface triggered by UV photoinitiation. The experimental conditions (monomer content, time of irradiation) were optimized on silica monolithic columns by monitoring the evolution of the chromatographic properties (retention, permeability, efficiency) in HILIC mode using a set of nucleosides as test solutes. Compared to thermal polymerization process, the photoinitiation allows the preparation of highly retentive and efficient HILIC monolithic columns in less than 10min of irradiation. This process was then successfully applied to the surface coating of fused silica capillary walls. In addition to its relative high stability and ability to reduce the electroosmotic flow, this polyacrylamide coating is localizable. Benefits of this localizable photochemical process are highlighted through the conception of an in-line integrated bimodal microseparation tool combining a SPE preconcentration step on a photografted silica monolith and an electrokinetic separation step in a polyacrylamide photopolymerized capillary section. Two neuropeptides are used as model solutes to illustrate the suitability of this approach.

  12. Thermally stable hydrophobicity in electrospun silica/polydimethylsiloxane hybrid fibers

    Science.gov (United States)

    Wei, Zhonglin; Li, Jianjun; Wang, Chao; Cao, Jungang; Yao, Yongtao; Lu, Haibao; Li, Yibin; He, Xiaodong

    2017-01-01

    In order to improve practical performances of silica-based inorganic/organic hybrid fibers, silica/polydimethylsiloxane hydrophobic fibers were successfully prepared by electrospinning. Silica sol and polydimethylsiloxane can be mixed homogeneously and become stable precursor solution in dichloromethane, which allows the transformation of silica/polydimethylsiloxane precursor solution into ultrafine fibers. Flame can ignite organic groups in polydimethylsiloxane directly and destroy the hydrophobicity of hybrid fibers, but hydrophobic feature may survive if electrospun hybrid membrane is combined with thin stainless-steel-304 gauze of 150 meshes due to its thermally stable hydrophobicity (>600 °C).

  13. Dopamine-induced silica-polydopamine hybrids with controllable morphology.

    Science.gov (United States)

    Ho, Chia-Che; Ding, Shinn-Jyh

    2014-04-01

    Novel silica-polydopamine hybrids, with controllable morphology, are facilely fabricated in an emulsion system consisting of tetraethyl orthosilicate, dopamine, water, and NaOH under weakly basic conditions (pH 8.5-10). An increase in initial pH favors the formation of nano-structured spherical silica-PDA hybrids from a flocculated structure.

  14. Preparation of hybrid monolithic columns via "one-pot" photoinitiated thiol-acrylate polymerization for retention-independent performance in capillary liquid chromatography.

    Science.gov (United States)

    Zhang, Haiyang; Ou, Junjie; Liu, Zhongshan; Wang, Hongwei; Wei, Yinmao; Zou, Hanfa

    2015-09-01

    A novel "one-pot" approach was developed for ultrarapid preparation of various hybrid monolithic columns in UV-transparent fused-silica capillaries via photoinitiated thiol-acrylate polymerization of an acrylopropyl polyhedral oligomertic silsesquioxane (acryl-POSS) and a monothiol monomer (1-octadecanethiol or sodium 3-mercapto-1-propanesulfonate) within 5 min, in which the acrylate not only homopolymerizes, but also couples with the thiol. This unique combination of two types of free-radical reaction mechanisms offers a simple way to fabricate various acrylate-based hybrid monoliths. The physical characterization, including scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and thermal gravimetric analysis was performed. The results indicated that the monothiol monomers were successfully incorporated into acryl-POSS-based hybrid monoliths. The column efficiencies for alkylbenzenes on the C18-functionalized hybrid monolithic column reached to 60 000-73 500 plates/m at the velocity of 0.33 mm/s in capillary liquid chromatography, which was far higher than that of previously reported POSS-based columns prepared via thermal-initiated free-radical polymerization without adding any thiol monomers. By plotting the plate height (H) of the alkylbenzenes versus the linear velocity (u) of the mobile phase, the results revealed a retention-independent efficient performance of small molecules in the isocratic elution. These results indicated that more homogeneous hybrid monoliths formed via photoinitiated thiol-acrylate polymerization; particularly, the use of the multifunctional cross-linker possibly prevented the generation of gel-like micropores, reducing mass transfer resistance (C-term). Another sulfonate-containing hybrid monolithic column also exhibited hydrophobicity and ion-exchange mechanism, and the dynamic binding capacity was calculated as 71.1 ng/cm (75 μm i.d.).

  15. Synthesis of silver nanoparticles confined in hierarchically porous monolithic silica: a new function in aromatic hydrocarbon separations.

    Science.gov (United States)

    Zhu, Yang; Morisato, Kei; Li, Wenyan; Kanamori, Kazuyoshi; Nakanishi, Kazuki

    2013-03-01

    Silver nanoparticles (Ag NPs) have been homogeneously introduced into hierarchically porous monolithic silica columns with well-defined macropores and SBA-15-type hexagonally ordered mesopores by using ethanol as the mild reductant. Within the cylindrical silica mesopores treated with aminopropyl groups as the host, monocrystalline Ag NPs and nanorods are obtained after being treated in silver nitrate/ethanol solution at room temperature for different durations of reducing time. The loading of Ag NPs in the monolith can be increased to 33 wt % by the repetitive treatment, which also led to the formation of polycrystalline Ag nanorods in the mesopores. Although the bare silica column cannot separate aromatic hydrocarbons, good separation of those molecules by noncharged Ag NPs confined in the porous structure of the monolith has been for the first time demonstrated with the Ag NP-embedded silica column. The NP-embedded monolithic silica would be a powerful separation tool for hydrocarbons with different number, position, and configuration of unsaturated bonds.

  16. Hybrid silica-PVA nanofibers via sol-gel electrospinning.

    Science.gov (United States)

    Pirzada, Tahira; Arvidson, Sara A; Saquing, Carl D; Shah, S Sakhawat; Khan, Saad A

    2012-04-03

    We report on the synthesis of poly(vinyl alcohol) (PVA)-silica hybrid nanofibers via sol-gel electrospinning. Silica is synthesized through acid catalysis of a silica precursor (tetraethyl orthosilicate (TEOS) in ethanol-water), and fibers are obtained by electrospinning a mixture of the silica precursor solution and aqueous PVA. A systematic investigation on how the amount of TEOS, the silica-PVA ratio, the aging time of the silica precursor mixture, and the solution rheology influence the fiber morphology is undertaken and reveals a composition window in which defect-free hybrid nanofibers with diameters as small as 150 nm are obtained. When soaked overnight in water, the hybrid fibers remain intact, essentially maintaining their morphology, even though PVA is soluble in water. We believe that mixing of the silica precursor and PVA in solution initiates the participation of the silica precursor in cross-linking of PVA so that its -OH group becomes unavailable for hydrogen bonding with water. FTIR analysis of the hybrids confirms the disappearance of the -OH peak typically shown by PVA, while formation of a bond between PVA and silica is indicated by the Si-O-C peak in the spectra of all the hybrids. The ability to form cross-linked nanofibers of PVA using thermally stable and relatively inert silica could broaden the scope of use of these materials in various technologies.

  17. Determination of phthalate esters in physiological saline solution by monolithic silica spin column extraction method%Determination of phthalate esters in physiological saline solution by monolithic silica spin column extraction method

    Institute of Scientific and Technical Information of China (English)

    Lu Lu; Yuki Hashi; Zhi-Hua Wang; Yuan Ma; Jin- Ming Lin

    2011-01-01

    Monolithic silica spin column extraction (MonoSpin-SPE) was developed as a simple, sensitive, and eco-friendly pretreatment method which combined with ultra-fast liquid chromatography-mass spectrometry (UFLC-MS) to determine the levels of six phthalate es

  18. Monolithic silica-based capillary reversed-phase liquid chromatography/electrospray mass spectrometry for plant metabolomics

    NARCIS (Netherlands)

    Tolstikov, V.V.; Lommen, A.; Nakanishi, K.; Tanaka, N.; Fiehn, O.

    2003-01-01

    Application of C18 monolithic silica capillary columns in HPLC coupled to ion trap mass spectrometry detection was studied for probing the metabolome of the model plant Arabidopsis thaliana. It could be shown that the use of a long capillary column is an easy and effective approach to reduce ionizat

  19. Degradation of orange dyes and carbamazepine by soybean peroxidase immobilized on silica monoliths and titanium dioxide.

    Science.gov (United States)

    Calza, Paola; Zacchigna, Dario; Laurenti, Enzo

    2016-12-01

    In this paper, the removal of three common dyes (orange I, orange II, and methylorange) and of the anticonvulsant drug carbamazepine from aqueous solutions by means of enzymatic and photocatalytic treatment was studied. Soybean peroxidase (SBP) was used as biocatalyst, both free in solution and immobilized on silica monoliths, and titanium dioxide as photocatalyst. The combination of the two catalysts led to a faster (about two to four times) removal of all the orange dyes compared to the single systems. All the dyes were completely removed within 2 h, also in the presence of immobilized SBP. As for carbamazepine, photocatalytic treatment prevails on the enzymatic degradation, but the synergistic effect of two catalysts led to a more efficient degradation; carbamazepine's complete disappearance was achieved within 60 min with combined system, while up to 2 h is required with TiO2 only.

  20. Functionalization of hybrid monolithic columns via thiol-ene click reaction for proteomics analysis.

    Science.gov (United States)

    Liu, Zhongshan; Liu, Jing; Liu, Zheyi; Wang, Hongwei; Ou, Junjie; Ye, Mingliang; Zou, Hanfa

    2017-05-19

    The vinyl-functionalized hybrid monolithic columns (75 and 150μm i.d.) were prepared via sol-gel chemistry of tetramethoxysilane (TMOS) and vinyltrimethoxysilane (VTMS). The content of accessible vinyl groups was further improved after the monolithic column was post-treated with vinyldimethylethoxysilane (VDMES). The surface properties of monolithic columns were tailored via thiol-ene click reaction by using 1-octadecanethiol, sodium 3-mercapto-1-propanesulfonate and 2,2'-(ethylenedioxy)diethanethiol/vinylphosphonic acid, respectively. The preparing octadecyl-functionalized monolithic columns were adopted for proteomics analysis in cLC-MS/MS. A 37-cm-long×75-μm-i.d. monolithic column could identify 3918 unique peptides and 1067 unique proteins in the tryptic digest of proteins from HeLa cells. When a 90-cm-long×75-μm-i.d. monolithic column was used, the numbers of unique peptides and proteins were increased by 82% and 32%, respectively. Furthermore, strong cation exchange (SCX) monolithic columns (4cm in length×150μm i.d.) were also prepared and coupled with the 37-cm-long×75-μm-i.d. octadecyl-functionalized monolithic column for two-dimensional SCX-RPLC-MS/MS analysis, which could identify 17114 unique peptides and 3211 unique proteins. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Hybrid Polyamide/Silica Nanocomposites : Synthesis and Mechanical Testing

    NARCIS (Netherlands)

    van Zyl, W.E.; Garcia, M.; Schrauwen, B.A.G.; Kooi, B.J.; De Hosson, Jeff Th.M.; Verweij, H.

    2002-01-01

    A hybrid inorganic-polymer composite was formed through nanosize silica filler particles (<30 nm) that were incorporated inside a nylon-6 matrix. The composite was microtomed and examined with TEM which revealed that the silica particles were well dispersed and non-aggregated. Optimization of the sy

  2. High-performance liquid chromatography separation of unsaturated organic compounds by a monolithic silica column embedded with silver nanoparticles.

    Science.gov (United States)

    Zhu, Yang; Morisato, Kei; Hasegawa, George; Moitra, Nirmalya; Kiyomura, Tsutomu; Kurata, Hiroki; Kanamori, Kazuyoshi; Nakanishi, Kazuki

    2015-08-01

    The optimization of a porous structure to ensure good separation performances is always a significant issue in high-performance liquid chromatography column design. Recently we reported the homogeneous embedment of Ag nanoparticles in periodic mesoporous silica monolith and the application of such Ag nanoparticles embedded silica monolith for the high-performance liquid chromatography separation of polyaromatic hydrocarbons. However, the separation performance remains to be improved and the retention mechanism as compared with the Ag ion high-performance liquid chromatography technique still needs to be clarified. In this research, Ag nanoparticles were introduced into a macro/mesoporous silica monolith with optimized pore parameters for high-performance liquid chromatography separations. Baseline separation of benzene, naphthalene, anthracene, and pyrene was achieved with the theoretical plate number for analyte naphthalene as 36,000 m(-1). Its separation function was further extended to cis/trans isomers of aromatic compounds where cis/trans stilbenes were chosen as a benchmark. Good separation of cis/trans-stilbene with separation factor as 7 and theoretical plate number as 76,000 m(-1) for cis-stilbene was obtained. The trans isomer, however, is retained more strongly, which contradicts the long- established retention rule of Ag ion chromatography. Such behavior of Ag nanoparticles embedded in a silica column can be attributed to the differences in the molecular geometric configuration of cis/trans stilbenes.

  3. Proton Conduction in Sulfonated Organic-Inorganic Hybrid Monoliths with Hierarchical Pore Structure.

    Science.gov (United States)

    von der Lehr, Martin; Seidler, Christopher F; Taffa, Dereje H; Wark, Michael; Smarsly, Bernd M; Marschall, Roland

    2016-09-28

    Porous organic-inorganic hybrid monoliths with hierarchical porosity exhibiting macro- and mesopores are prepared via sol-gel process under variation of the mesopore size. Organic moieties in the pore walls are incorporated by substituting up to 10% of the silicon precursor tetramethylorthosilicate with bisilylated benzene molecules. After functionalization with sulfonic acid groups, the resulting sulfonated hybrid monoliths featuring a bimodal pore structure are investigated regarding proton conduction depending on temperature and relative humidity. The hierarchical pore system and controlled mesopore design turn out to be crucial for sulfonation and proton conduction. These sulfonated hybrid hierarchical monoliths containing only 10% organic precursor exhibit higher proton conduction at different relative humidities than sulfonated periodic mesoporous organosilica made of 100% bisilylated precursors exhibiting solely mesopores, even with a lower concentration of sulfonic acid groups.

  4. Monolithic formulation of electromechanical systems within the context of hybrid finite elements

    Science.gov (United States)

    Agrawal, Manish; Jog, C. S.

    2017-03-01

    In electromechanical devices, a strong coupling exists between the electromagnetic and displacement field. Due to this strong interaction, a need arises to develop a robust, fully coupled scheme for modeling electromechanical phenomena. With this goal in view, we present a monolithic numerical scheme for modeling fully coupled electromechanical systems. It is shown in the literature that for structural problems, hybrid elements that are based on a two-field variational formulation are less susceptible to locking and provide a robust numerical strategy especially for shell-type structures. Hence, we extend our monolithic formulation to the hybrid finite element framework. Our monolithic formulation is based on a total Lagrangian framework, where the eddy current and structural equations are solved on the reference configuration. Consistent linearization is performed to ensure a quadratic rate of convergence. The efficacy of the presented algorithm, and especially that of the hybrid formulation is demonstrated with the help of numerical examples.

  5. Synthesis of Mesoporous Titania-Silica Monolith Composites — A Comprehensive Study on their Photocatalytic Degradation of Acid Blue 113 Dye Under UV Light

    Science.gov (United States)

    Thejaswini, Thurlapathi Vl; Prabhakaran, Deivasigamani

    2016-10-01

    The present work deals with the synthesis of bi-continuous macro and mesoporous crack-free titania-silica monoliths, with well-defined structural dimensions and high surface area. The work also highlights their potential photocatalytic environmental applications. The highly ordered titania-silica monoliths are synthesized through direct surface template method using organic precursors of silica and titania in the presence of surface directing agents such as pluronic P123 and PEG, under acetic acid medium. The monoliths are synthesized with different Ti/Si ratios to obtain monolithic designs that exhibit better photocatalytic activity for dye degradation. The titania-silica monoliths are characterized using XRD, SEM, EDAX, FT-IR, TG-DTA and BET analysis. The photocatalytic activity of the synthesized monoliths is tested on the photodegradation of a textile dye (acid blue 113). It is observed that the monolith with 7:3 ratio of Ti/Si showed significant photocatalysis behavior in the presence of UV light. The influence of various physico-chemical properties such as, solution pH, photocatalyst dosage, light intensity, dye concentration, effect of oxidants, etc. are analyzed and optimized using a customized photoreactor set-up. Under optimized conditions, the monoliths exhibited superior degradation kinetics, with the dye dissipation complete within 10min of photolysis. The mesoporous catalysts are recoverable and reusable up to four cycles of repeated usage.

  6. Photoluminescent red, green and blue monoliths of new Eu(III), Tb(III) and Y(III) complexes embedded in silica matrix

    Science.gov (United States)

    Stan, Corneliu S.; Popa, Marcel; Sutiman, Daniel; Horlescu, Petronela

    2014-07-01

    Large transparent photoluminescent monoliths were prepared by embedding newly synthesized Eu(III), Tb(III) and Y(III) complexes with 2-(1H-1,2,4-Triazol-3-yl)pyridine ligand in silica matrices through a modified sol-gel process. The remarkable luminescent properties of the free complexes were preserved in silica matrix, resulting in red, green and blue monoliths with a shape that may be tailored during the gelation process according to specific applications. Prior to embedment, the complexes prepared at 1/3 metal to ligand ratio were investigated through elemental analysis, thermal analysis, FT-IR, mass and fluorescence spectroscopy while the obtained silica monoliths were supplementary investigated through SEM and fluorescence spectroscopy. The emission peaks are located at 612 nm for the monolithic silica embedded Eu(III) complex, at 542 nm for the monolithic silica embedded Tb(III) complex and at 482 nm respectively for the silica monolith containing the Y(III) complex. Their excellent photoluminescent properties may recommend them as photonic conversion materials in various optoelectronic applications.

  7. Rapid Preparation Methods of Biological Samples for Ionic Compounds Using Ion Exchange Type Monolithic Silica Spin Column

    OpenAIRE

    宮崎, 将太; 山田, 智子; 太田, 茂徳; 斉藤, 剛; 奈女良, 昭; 大平, 真義

    2010-01-01

    We developed a device comprising a spin column packed with ion exchange type (SCX and SAX) monolithic silica for extracting ionic compounds from biological samples. The methods involving the use of these spin column are not useful for the extraction of ionic analytes, but are highly reproducible for the analysis in serum and urine. This spin column enabled sample preparation in less than 10 min. Handling such as sample loading, washing, and elution of analytes, was exhibited by the centrifuga...

  8. Optical study of the ultrasonic formation process of noble metal nanoparticles dispersed inside the pores of monolithic mesoporous silica

    CERN Document Server

    Fu Gan Hua; Kan Cai Xia; Li Cun Cheng; Fang Qi

    2003-01-01

    Gold nanoparticles dispersed inside the pores of monolithic mesoporous silica were prepared by soaking the silica in a gold (III) ion solution and subsequent ultrasound irradiation. The formation process of gold nanoparticles in the pores of mesoporous silica was investigated based on optical measurements of wrapped and naked soaked silica after ultrasonic irradiation, and the reduction rate effect in solution and pre-soaking effect. It has been shown that acoustic cavitation cannot occur in nano-sized pores. The gold nanoparticles in silica are not formed in situ within the pores but produced mainly by diffusion of the gold clusters formed in the solution during irradiation into the pores. The radicals formed in solution are exhausted before entering the pores of silica. There exists a critical reduction rate in solution, at which the yield of gold nanoparticles in silica reaches a maximum, and above which there is a decrease in the yield. This is attributed to too quick a growth or aggregation of gold clust...

  9. Antibody-coupled monolithic silica microtips for highthroughput molecular profiling of circulating exosomes.

    Science.gov (United States)

    Ueda, Koji; Ishikawa, Nobuhisa; Tatsuguchi, Ayako; Saichi, Naomi; Fujii, Risa; Nakagawa, Hidewaki

    2014-08-29

    Exosome-mediated signal transportation plays a variety of critical roles in cancer progression and metastasis. From the aspect of cancer diagnosis, circulating exosomes are ideal resources of biomarkers because molecular features of tumor cells are transcribed on them. However, isolating pure exosomes from body fluids is time-consuming and still major challenge to be addressed for comprehensive profiling of exosomal proteins and miRNAs. Here we constructed anti-CD9 antibody-coupled highly porous monolithic silica microtips which allowed automated rapid and reproducible exosome extraction from multiple clinical samples. We applied these tips to explore lung cancer biomarker proteins on exosomes by analyzing 46 serum samples. The mass spectrometric quantification of 1,369 exosomal proteins identified CD91 as a lung adenocarcinoma specific antigen on exosomes, which was further validated with CD9-CD91 exosome sandwich ELISA measuring 212 samples. Our simple device can promote not only biomarker discovery studies but also wide range of omics researches about exosomes.

  10. Rapid determination of amino acids in biological samples using a monolithic silica column.

    Science.gov (United States)

    Song, Yanting; Funatsu, Takashi; Tsunoda, Makoto

    2012-05-01

    A high-performance liquid chromatography method in which fluorescence detection is used for the simultaneous determination of 21 amino acids is proposed. Amino acids were derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) and then separated on a monolithic silica column (MonoClad C18-HS, 150 mm×3 mm i.d.). A mixture of 25 mM citrate buffer containing 25 mM sodium perchlorate (pH 5.5) and acetonitrile was used as the mobile phase. We found that the most significant factor in the separation was temperature, and a linear temperature gradient from 30 to 49°C was used to control the column temperature. The limits of detection and quantification for all amino acids ranged from 3.2 to 57.2 fmol and 10.8 to 191 fmol, respectively. The calibration curves for the NBD-amino acid had good linearity within the range of 40 fmol to 40 pmol when 6-aminocaproic acid was used as an internal standard. Using only conventional instruments, the 21 amino acids could be analyzed within 10 min. This method was found to be suitable for the quantification of the contents of amino acids in mouse plasma and adrenal gland samples.

  11. Molecular Organization Induced Anisotropic Properties of Perylene - Silica Hybrid Nanoparticles.

    Science.gov (United States)

    Sriramulu, Deepa; Turaga, Shuvan Prashant; Bettiol, Andrew Anthony; Valiyaveettil, Suresh

    2017-08-10

    Optically active silica nanoparticles are interesting owing to high stability and easy accessibility. Unlike previous reports on dye loaded silica particles, here we address an important question on how optical properties are dependent on the aggregation-induced segregation of perylene molecules inside and outside the silica nanoparticles. Three differentially functionalized fluorescent perylene - silica hybrid nanoparticles are prepared from appropriate ratios of perylene derivatives and tetraethyl orthosilicate (TEOS) and investigated the structure property correlation (P-ST, P-NP and P-SF). The particles differ from each other on the distribution, organization and intermolecular interaction of perylene inside or outside the silica matrix. Structure and morphology of all hybrid nanoparticles were characterized using a range of techniques such as electron microscope, optical spectroscopic measurements and thermal analysis. The organizations of perylene in three different silica nanoparticles were explored using steady-state fluorescence, fluorescence anisotropy, lifetime measurements and solid state polarized spectroscopic studies. The interactions and changes in optical properties of the silica nanoparticles in presence of different amines were tested and quantified both in solution and in vapor phase using fluorescence quenching studies. The synthesized materials can be regenerated after washing with water and reused for sensing of amines.

  12. Determination of ricin by nano liquid chromatography/mass spectrometry after extraction using lactose-immobilized monolithic silica spin column.

    Science.gov (United States)

    Kanamori-Kataoka, Mieko; Kato, Haruhito; Uzawa, Hirotaka; Ohta, Shigenori; Takei, Yoshiyuki; Furuno, Masahiro; Seto, Yasuo

    2011-08-01

    Ricin is a glycosylated proteinous toxin that is registered as toxic substance by Chemical Weapons convention. Current detection methods can result in false negatives and/or positives, and their criteria are not based on the identification of the protein amino acid sequences. In this study, lactose-immobilized monolithic silica extraction followed by tryptic digestion and liquid chromatography/mass spectrometry (LC/MS) was developed as a method for rapid and accurate determination of ricin. Lactose, which was immobilized on monolithic silica, was used as a capture ligand for ricin extraction from the sample solution, and the silica was supported in a disk-packed spin column. Recovery of ricin was more than 40%. After extraction, the extract was digested with trypsin and analyzed by LC/MS. The accurate masses of molecular ions and MS/MS spectra of the separated peptide peaks were measured by Fourier transform-MS and linear iontrap-MS, respectively. Six peptides, which were derived from the ricin A-(m/z 537.8, 448.8 and 586.8) and B-chains (m/z 701.3, 647.8 and 616.8), were chosen as marker peptides for the identification of ricin. Among these marker peptides, two peptides were ricin-specific. This method was applied to the determination of ricin from crude samples. The monolithic silica extraction removed most contaminant peaks from the total ion chromatogram of the sample, and the six marker peptides were clearly detected by LC/MS. It takes about 5 h for detection and identification of more than 8 ng/ml of ricin through the whole handling, and this procedure will be able to deal with the terrorism using chemical weapon.

  13. Highly bioactive polysiloxane modified bioactive glass-poly(ethylene glycol) hybrids monoliths with controlled surface structure for bone tissue regeneration

    Science.gov (United States)

    Chen, Jing; Que, Wenxiu; Xing, Yonglei; Lei, Bo

    2015-03-01

    Crack-free monoliths with controllable surface microstructure have high bioactivities and therefore potential applications in bone tissue regeneration. In this paper, crack-free polydimethylsiloxane-modified bioactive glass-poly (ethylene glycol) (PDMS-BG-PEG) hybrids monoliths were fabricated via using a modified sol-gel process. Results show that the addition of PEG plays an important part in the formation of crack-free and gelation of the monoliths, and surface microstructures of the as-prepared hybrid monoliths were significantly influenced by the concentration and molecular weight of PEG. The samples obtained from PEG 300 had porous surface result in higher bioactivity (apatite formation) in simulated body fluid (SBF), while the samples obtained from PEG 600 had the smooth surface and inhibited the formation of apatite layer in SBF. These as-prepared hybrid monoliths can be used as a good candidate of implant and scaffold for highly efficient bone tissue regeneration.

  14. Preparation and characterization of functional silica hybrid magnetic nanoparticles

    Science.gov (United States)

    Digigow, Reinaldo G.; Dechézelles, Jean-François; Dietsch, Hervé; Geissbühler, Isabelle; Vanhecke, Dimitri; Geers, Christoph; Hirt, Ann M.; Rothen-Rutishauser, Barbara; Petri-Fink, Alke

    2014-08-01

    We report on the synthesis and characterization of functional silica hybrid magnetic nanoparticles (SHMNPs). The co-condensation of 3-aminopropyltriethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) in presence of superparamagnetic iron oxide nanoparticles (SPIONs) leads to hybrid magnetic silica particles that are surface-functionalized with primary amino groups. In this work, a comprehensive synthetic study is carried out and completed by a detailed characterization of hybrid particles' size and morphology, surface properties, and magnetic responses using different techniques. Depending on the mass ratio of SPIONs and the two silanes (TEOS and APTES), we were able to adjust the number of surface amino groups and tune the magnetic properties of the superparamagnetic hybrid particles.

  15. Textural characterization of native and n-alky-bonded silica monoliths by mercury intrusion/extrusion, inverse size exclusion chromatography and nitrogen adsorption.

    Science.gov (United States)

    Thommes, M; Skudas, R; Unger, K K; Lubda, D

    2008-05-16

    Native and n-alkyl-bonded (n-octadecyl) monolithic silica rods with mesopores in the range between 10 and 25 nm and macropores in the range between 1.8 and 6.0 microm were examined by mercury intrusion/extrusion, inverse size exclusion chromatography (ISEC) and nitrogen sorption. Our results reveal very good agreement for the mesopore size distribution obtained from nitrogen adsorption (in combination with an advanced NLDFT analysis) and ISEC. Our studies highlight the importance of mercury porosimetry for the assessment of the macropore size distribution and show that mercury porosimetry is the only method which allows obtaining a combined and comprehensive structural characterization of macroporous/mesoporous silica monoliths. Our data clearly confirm that mercury porosimetry hysteresis and entrapment have different origin, and indicate the intrinsic nature of mercury porosimetry hysteresis in these silica monoliths. Within this context some silica monoliths show the remarkable result of no entrapment of mercury after extrusion from the mesopore system (i.e. for the first intrusion/extrusion cycle). The results of a systematic study of the mercury intrusion/extrusion behavior into native silica monoliths and monoliths with bonded n-alkyl groups reveals that the macro (through) pore structure, which controls the mass transfer to and from the mesopores, here mainly controls the entrapment behavior. Our data suggest that mercury intrusion/extrusion porosimetry does not only allow to obtain a comprehensive pore structure analysis, but can also serve as a tool to estimate the mass transport properties of silica monoliths to be employed in liquid-phase separation processes.

  16. On the improvement of mechanical properties of monolithic silica aerogels (for transparent insulating material); Silica aerogel (tomei dannetsu zairyo) kyodo no kaizen ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Tajiri, K.; Igarashi, K.; Tanemura, S. [National Industrial Research Institute of Nagoya, Nagoya (Japan)

    1997-11-25

    Study was made on improvement of the strength of silica aerogel as transparent insulating material. Silica aerogel is a low-density porous material with high heat insulation and transparency. To develop a insulating material with high transparency, monolithic silica aerogel was studied. For direct use of it for windows, its strength improvement was attempted. The aerogel was prepared by supercritical drying (alcohol or CO2) of silica wet gel obtained by hydrolysis and condensation of silicon alkoxide solution. To prepare the aerogel bonded on plate glass for strength improvement, the aerogel was bonded to alkoxide by exposing active silanol radical through F-etching of plate glass surface. However, to obtain the practical large-area bonded aerogel, shrinkage control of the aerogel in supercritical drying was necessary. Addition of Laponite into a silica network for strength improvement by polymer increased the bending strength by 50%. Although some reduction of its transparency was observed because of clouding, its heat insulation was stable. Further strength improvement is necessary for its practical use. 5 figs., 1 tab.

  17. Mechanical quality factor measurements of monolithically suspended fused silica test masses of the GEO 600 gravitational wave detector

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J R [Max-Planck-Institute for Gravitational Physics (Albert-Einstein-Institute) and University of Hannover, Callinstr. 38, D-30167 Hannover (Germany); Cagnoli, G [Institute for Gravitational Research, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Crooks, D R M [Institute for Gravitational Research, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Fejer, M M [Edward L Ginzton Laboratory, Stanford University, Stanford, CA 94305-4088 (United States); Gossler, S [Max-Planck-Institute for Gravitational Physics (Albert-Einstein-Institute) and University of Hannover, Callinstr. 38, D-30167 Hannover (Germany); Lueck, H [Max-Planck-Institute for Gravitational Physics (Albert-Einstein-Institute) and University of Hannover, Callinstr. 38, D-30167 Hannover (Germany); Rowan, S [Institute for Gravitational Research, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Hough, J [Institute for Gravitational Research, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Danzmann, K [Max-Planck-Institute for Gravitational Physics (Albert-Einstein-Institute) and University of Hannover, Callinstr. 38, D-30167 Hannover (Germany)

    2004-03-07

    Internal thermal noise is expected to be a limiting noise source in the most sensitive frequency band of the GEO 600 gravitational wave detector. Because thermal noise is directly related to energy dissipation, care has been taken to construct test mass suspensions from low-dissipation materials and to eliminate inter-material rubbing where possible. Recently, the GEO 600 team finished the installation of triple-pendulum suspensions for the optics of the Michelson interferometer. Each of these triple pendulums incorporates a monolithic fused silica pendulum as the lowest stage. We have made internal mode quality factor measurements of three monolithically suspended test masses. Using these measurements we estimate of the level of internal thermal noise in the GEO 600 interferometer.

  18. Mechanical quality factor measurements of monolithically suspended fused silica test masses of the GEO 600 gravitational wave detector

    Science.gov (United States)

    Smith, J. R.; Cagnoli, G.; Crooks, D. R. M.; Fejer, M. M.; Goßler, S.; Lück, H.; Rowan, S.; Hough, J.; Danzmann, K.

    2004-03-01

    Internal thermal noise is expected to be a limiting noise source in the most sensitive frequency band of the GEO 600 gravitational wave detector. Because thermal noise is directly related to energy dissipation, care has been taken to construct test mass suspensions from low-dissipation materials and to eliminate inter-material rubbing where possible. Recently, the GEO 600 team finished the installation of triple-pendulum suspensions for the optics of the Michelson interferometer. Each of these triple pendulums incorporates a monolithic fused silica pendulum as the lowest stage. We have made internal mode quality factor measurements of three monolithically suspended test masses. Using these measurements we estimate of the level of internal thermal noise in the GEO 600 interferometer.

  19. Novel bioactive materials: silica aerogel and hybrid silica aerogel/pseudo wollastonite

    Energy Technology Data Exchange (ETDEWEB)

    Resendiz-Hernandez, P. J.; Cortes-Hernandez, D. a.; Saldivar-Ramirez, M. M. G.; Acuna-gutierrez, I. O.; Flores-Valdes, A.; Torres-rincon, S.; Mendez-Nonell, J.

    2014-07-01

    Silica aerogel and hybrid silica aerogel/pseudo wollastonite materials were synthesized by controlled hydrolysis of tetraethoxysilane (TEOS) using also methanol (MeOH) and pseudo wollastonite particles. The gels obtained were dried using a novel process based on an ambient pressure drying. Hexane and hexamethyl-disilazane (HMDZ) were the solvents used to chemically modify the surface. In order to assess bioactivity, aerogels, without and with pseudowollastonite particles, were immersed in simulated body fluid (SBF) for 7 and 14 days. The hybrid silica aerogel/pseudo wollastonite showed a higher bioactivity than that observed for the single silica aerogel. However, as in both cases a lower bioactivity was observed, a biomimetic method was also used to improve it. In this particular method, samples of both materials were immersed in SBF for 7 days followed by their immersion in a more concentrated solution (1.5 SBF) for 14 days. A thick and homogeneous bonelike apatite layer was formed on the biomimetically treated materials. Thus, bioactivity was successfully improved even on the aerogel with no pseudowollastonite particles. As expected, the hybrid silica aerogel/pseudowollastonite particles showed a higher bioactivity. (Author)

  20. Facile synthesis of zirconia doped hybrid organic inorganic silica membranes

    NARCIS (Netherlands)

    Hove, ten M.; Nijmeijer, A.; Winnubst, A.J.A.

    2015-01-01

    Hybrid organic inorganic silica membranes are interesting candidates for gas-separation applications due to their excellent hydrothermal stability. However, up to now these membranes lack the separation performance required to separate hydrogen from carbon dioxide. In this work a procedure for dopin

  1. Preparation, characterization and application of organic-inorganic hybrid caffeine imprinted monolith.

    Science.gov (United States)

    Liu, Xiaofang; Sun, Na; Zhu, Quanfei; Wu, Mei; Ye, Yong; Chen, Huaixia

    2013-08-23

    The present work aims to synthesize an organic-inorganic hybrid caffeine imprinted monolith using one-step method. The synthesis conditions such as the type of inorganic precursor and porogenic solvent, the molar ratios of the monomer and cross-linker, the volume ratio of the inorganic alcoholysate and organic part were optimized. The morphology of the monolith was studied by scanning electron microscopy and Fourier transform infrared spectra. The imprinted factor of the monolith for caffeine reached 3.02. A simple, rapid and sensitive method for the determination of caffeine in children's milk using the organic-inorganic hybrid caffeine imprinted polymer monolith microextraction combined with high-performance liquid chromatography-photodiodes array detector was developed. Several parameters affecting the sample pretreatment were investigated, including the type, flow rate and volume of eluent, the flow rate and volume of sample solution. The assay exhibited a linear dynamic range of 8-500μgL(-1) with the correlation coefficient above 0.9987. Lower limits of detection (LOD, at S/N=3) and quantification (LOQ, at S/N=10) in children's milk samples were 2.7 and 8μgL(-1). Recoveries of caffeine from spiked children's milk ranged from 85 to 104% with relative standard deviations of less than 8.9%.

  2. Hybrid integrated PDMS microfluidics with a silica capillary.

    Science.gov (United States)

    Dimov, Ivan K; Riaz, Asif; Ducrée, Jens; Lee, Luke P

    2010-06-07

    To harness the properties of both PDMS and silica, we have demonstrated hybrid integrated PDMS microfluidic systems with fused silica capillaries. The hybrid integrated PDMS microfluidics and silica capillary (iPSC) modules exhibit a novel architecture and method for leakage free CE sample injection merely requiring a single high voltage source and one pair of electrodes. The use of the iPSC device is based on a modular approach which allows the capillary to be reused extensively whilst replacing the attached fluidic module for different experiments. Integrating fused silica capillaries with PDMS microfluidic modules allows the direct application of a wide variety of well established conventional CE protocols for separations of complex analytes. Furthermore it bears the potential for facile coupling to standard electro-spray ionization mass spectrometry (ESI-MS), letting users focus on the sample analysis rather than the development of new separation protocols. The fabrication of the iPSC module consists of a simple and quick three-step method that submerges a fused silica capillary in PDMS prepolymer. After cross linking the prepolymer and punching the inlets, the iPSC module layer can be mounted onto a microfluidic device for CE separation.

  3. Temperature dependent NIR emitting lanthanide-PMO/silica hybrid materials.

    Science.gov (United States)

    Kaczmarek, Anna M; Esquivel, Dolores; Ouwehand, Judith; Van Der Voort, Pascal; Romero-Salguero, Francisco J; Van Deun, Rik

    2017-06-28

    Two materials - a mesoporous silica (MS) and a periodic mesoporous organosilica (PMO) functionalized with dipyridyl-pyridazine (dppz) units were grafted with near-infrared (NIR) emitting lanthanide (Nd(3+), Er(3+), Yb(3+)) complexes in an attempt to obtain hybrid NIR emitting materials. The parent materials: dppz-vSilica and dppz-ePMO were prepared by a hetero Diels-Alder reaction between 3,6-di(2-pyridyl)-1,2,4,5-tetrazine (dptz) and the double bonds of either ethenylene-bridged PMO (ePMO) or vinyl-silica (vSilica) and subsequent oxidation. The dppz-vSilica is reported here for the first time. The prepared lanthanide-PMO/silica hybrid materials were studied in depth for their luminescence properties at room temperature and chosen Nd(3+) and Yb(3+) samples also at low temperature (as low as 10 K). We show that both the dppz-vSilica and dppz-ePMO materials can be used as "platforms" for obtaining porous materials showing NIR luminescence. To obtain NIR emission these materials can be excited either in the UV or Vis region (into the π→π* transitions of the ligands or directly into the f-f transitions of the Ln(3+) ions). More interestingly, when functionalized with Nd(3+) or Yb(3+)β-diketonate complexes these materials showed interesting luminescence properties over a wide temperature range (10-360 K). The Yb(3+) materials were investigated for their potential use as ratiometric temperature sensors.

  4. Mesoporous silica nanotubes hybrid membranes for functional nanofiltration

    Energy Technology Data Exchange (ETDEWEB)

    El-Safty, Sherif A; Shahat, Ahmed; Mekawy, Moataz; Nguyen, Hoa; Warkocki, Wojciech; Ohnuma, Masato, E-mail: sherif.elsafty@nims.go.jp, E-mail: sherif@aoni.waseda.jp [National Institute for Materials Science, Exploratory Materials Research Laboratory for Energy and Environment, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047 (Japan)

    2010-09-17

    The development of nanofiltration systems would greatly assist in the production of well-defined particles and biomolecules with unique properties. We report a direct, simple synthesis of hexagonal silica nanotubes (NTs), which vertically aligned inside anodic alumina membranes (AAM) by means of a direct templating method of microemulsion phases with cationic surfactants. The direct approach was used as soft templates for predicting ordered assemblies of surfactant/silica composites through strong interactions within AAM pockets. Thus, densely packed NTs were successfully formed in the entirety of the AAM channels. These silica NTs were coated with layers of organic moieties to create a powerful technique for the ultrafine filtration. The resulting modified-silica NTs were chemically robust and showed affinity toward the transport of small molecular particles. The rigid silica NTs inside AAM channels had a pore diameter of {<=} 4 nm and were used as ultrafine filtration systems for noble metal nanoparticles (NM NPs) and semiconductor nanocrystals (SC NCs) fabricated with a wide range of sizes (1.0-50 nm) and spherical/pyramidal morphologies. Moreover, the silica NTs hybrid membranes were also found to be suitable for separation of biomolecules such as cytochrome c (CytC). Importantly, this nanofilter design retains high nanofiltration efficiency of NM NPs, SC NCs and biomolecules after a number of reuse cycles. Such retention is crucial in industrial applications.

  5. Highly luminescent and ultrastable CsPbBr{sub 3} perovskite quantum dots incorporated into a silica/alumina monolith

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhichun; Kong, Long; Huang, Shouqiang; Li, Liang [School of Environmental Science and Engineering, Shanghai Jiao Tong University (China)

    2017-07-03

    We successfully prepared QDs incorporated into a silica/alumina monolith (QDs-SAM) by a simple sol-gel reaction of an Al-Si single precursor with CsPbBr{sub 3} QDs blended in toluene solution, without adding water and catalyst. The resultant transparent monolith exhibits high photoluminescence quantum yields (PLQY) up to 90 %, and good photostability under strong illumination of blue light for 300 h. We show that the preliminary ligand exchange of didodecyl dimethyl ammonium bromide (DDAB) was very important to protect CsPbBr{sub 3} QDs from surface damages during the sol-gel reaction, which not only allowed us to maintain the original optical properties of CsPbBr{sub 3} QDs but also prevented the aggregation of QDs and made the monolith transparent. The CsPbBr{sub 3} QDs-SAM in powder form was easily mixed into the resins and applied as color-converting layer with curing on blue light-emitting diodes (LED). The material showed a high luminous efficacy of 80 lm W{sup -1} and a narrow emission with a full width at half maximum (FWHM) of 25 nm. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Synthesis and Gas Transport Properties of Hyperbranched Polyimide–Silica Hybrid/Composite Membranes

    Directory of Open Access Journals (Sweden)

    Masako Miki

    2013-12-01

    Full Text Available Hyperbranched polyimide–silica hybrids (HBPI–silica HBDs and hyperbranched polyimide–silica composites (HBPI–silica CPTs were prepared, and their general and gas transport properties were investigated to clarify the effect of silica sources and preparation methods. HBPI–silica HBDs and HBPI–silica CPTs were synthesized by two-step polymerization of A2 + B3 monomer system via polyamic acid as precursor, followed by hybridizing or blending silica sources. Silica components were incorporated by the sol-gel reaction with tetramethoxysilane (TMOS or the addition of colloidal silica. In HBPI-silica HBDs, the aggregation of silica components is controlled because of the high affinity of HBPI and silica caused by the formation of covalent bonds between HBPI and silica. Consequently, HBPI-silica HBDs had good film formability, transparency, and mechanical properties compared with HBPI-silica CPTs. HBPI-silica HBD and CPT membranes prepared via the sol-gel reaction with TMOS showed specific gas permeabilities and permselectivities for CO2/CH4 separation, that is, both CO2 permeability and CO2/CH4 selectivity increased with increasing silica content. This result suggests that gas transport can occur through a molecular sieving effect of the porous silica network derived from the sol-gel reaction and/or through the narrow interfacial region between the silica networks and the organic matrix.

  7. Synthesis and properties of Chitosan-silica hybrid aerogels

    Energy Technology Data Exchange (ETDEWEB)

    Ayers, Michael R.; Hunt, Arlon J.

    2001-06-01

    Chitosan, a polymer that is soluble in dilute aqueous acid, is derived from chitin, a natural polyglucosamide. Aquagels where the solid phase consists of both chitosan and silica can be easily prepared by using an acidic solution of chitosan to catalyze the hydrolysis and condensation of tetraethylorthosilicate. Gels with chitosan/TEOS mass ratios of 0.1-1.1 have been prepared by this method. Standard drying processes using CO{sub 2} give the corresponding aerogels. The amount of chitosan in the gel plays a role in the shrinkage of the aerogel during drying. Gels with the lowest chitosan/silica ratios show the most linear shrinkage, up to 24%, while those with the highest ratios show only a 7% linear shrinkage. Pyrolysis at 700 C under nitrogen produces a darkened aerogel due to the thermal decomposition of the chitosan, however, the aerogel retains its monolithic form. The pyrolyzed aerogels absorb slightly more infrared radiation in the 2-5 {micro}m region than the original aerogels. B.E.T. surface areas of these aerogels range from 470-750 m{sup 2}/g. Biocompatibility screening of this material shows a very high value for hemolysis, but a low value for cytotoxicity.

  8. Preparation of polyhedral oligomeric silsesquioxane-based hybrid monolith by ring-opening polymerization and post-functionalization via thiol-ene click reaction.

    Science.gov (United States)

    Liu, Zhongshan; Ou, Junjie; Lin, Hui; Wang, Hongwei; Dong, Jing; Zou, Hanfa

    2014-05-16

    A polyhedral oligomeric silsesquioxane (POSS) hybrid monolith was simply prepared by using octaglycidyldimethylsilyl POSS (POSS-epoxy) and cystamine dihydrochloride as monomers via ring-opening polymerization. The effects of composition of prepolymerization solution and polycondensation temperature on the morphology and permeability of monolithic column were investigated in detail. The obtained POSS hybrid monolithic column showed 3D skeleton morphology and exhibited high column efficiency of ∼71,000 plates per meter in reversed-phase mechanism. Owing to this POSS hybrid monolith essentially possessing a great number of disulfide bonds, the monolith surface would expose thiol groups after reduction with dithiothreitol (DTT), which supplied active sites to functionalize with various alkene monomers via thiol-ene click reaction. The results indicated that the reduction with DTT could not destroy the 3D skeleton of hybrid monolith. Both stearyl methylacrylate (SMA) and benzyl methacrylate (BMA) were selected to functionalize the hybrid monolithic columns for reversed-phase liquid chromatography (RPLC), while [2-(methacryloyloxy)ethyl]-dimethyl-(3-sulfopropyl)-ammonium hydroxide (MSA) was used to modify the hybrid monolithic column in hydrophilic interaction chromatography (HILIC). These modified hybrid monolithic columns could be successfully applied for separation of small molecules with high efficiency. It is demonstrated that thiol-ene click reaction supplies a facile way to introduce various functional groups to the hybrid monolith possessing thiol groups. Furthermore, due to good permeability of the resulting hybrid monoliths, we also prepared long hybrid monolithic columns in narrow-bore capillaries. The highest column efficiency reached to ∼70,000 plates using a 1-m-long column of 75μm i.d. with a peak capacity of 147 for isocratic chromatography, indicating potential application in separation and analysis of complex biosamples. Copyright © 2014

  9. Fast, high-efficiency peptide separations on a 50-mu m reversed-phase silica monolith in a nanoLC-MS set-up

    NARCIS (Netherlands)

    Rieux, L; Lubda, D; Niederlander, HAG; Verpoorte, E; Bischoff, R

    2006-01-01

    Proteomic studies have stimulated the development of novel stationary phases in miniaturised chromatographic columns that permit high linear flow velocities and exhibit high resolving power. In this work, a 50-mu m reversed-phase silica-based monolith was chromatographically characterised for its us

  10. A hybrid fluorous monolithic capillary column with integrated nanoelectrospray ionization emitter for determination of perfluoroalkyl acids by nano-liquid chromatography-nanoelectrospray ionization-mass spectrometry/mass spectrometry.

    Science.gov (United States)

    Zhang, Haiyang; Ou, Junjie; Wei, Yinmao; Wang, Hongwei; Liu, Zhongshan; Zou, Hanfa

    2016-04-01

    A hybrid fluorous monolithic column was simply prepared via photo-initiated free radical polymerization of an acrylopropyl polyhedral oligomeric silsesquioxane (acryl-POSS) and a perfluorous monomer (2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate) in UV-transparent fused-silica capillaries within 5min. The physical characterization of hybrid fluorous monolith, including scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, mercury intrusion porosimetry (MIP) and nitrogen adsorption/desorption measurement was performed. Chromatographic performance was also evaluated by capillary liquid chromatography (cLC). Due to the fluorous-fluorous interaction between fluorous monolith and analytes, fluorobenzenes could well be separated, and the column efficiencies reached 86,600-92,500plates/m at the velocity of 0.87mm/s for alkylbenzenes and 51,900-76,000plates/m at the velocity of 1.10mm/s for fluorobenzenes. Meanwhile, an approach to integrate nanoelectrospray ionization (ESI) emitter with hybrid fluorous monolithic column was developed for quantitative determination of perfluoroalkyl acids by nanoHPLC-ESI-MS/MS. The integration design could minimize extracolumn volume, thus excluding undesirable peak broadening and improving separation performance.

  11. Femtosecond laser fabrication of waveguides in Rhodamine B-doped GPTS/TEOS-derived organic/silica monolithic xerogel

    Science.gov (United States)

    Ferreira, P. H. D.; Otuka, A. J. G.; Barbano, E. C.; Manoel, D. S.; De Vicente, F. S.; Vollet, D. R.; Donatti, D. A.; Misoguti, L.; Mendonça, C. R.

    2015-09-01

    This paper reports on the fabrication and characterization of waveguides inside of a dye doped-organic/inorganic bulk material using femtosecond laser microfabrication. Rhodamine B-doped GPTS/TEOS-derived organic/silica monolithic xerogels with excellent optical quality were prepared by sol-gel method. The influence of the dye concentration on the samples optical properties was also investigated in order to choose the proper one to be used for producing the waveguides. After investigation of parameters to fabrication in xerogels, such as, scan speed effects and pulse energy, we produced waveguides in bulks doped with 0.5 mmol/L of Rhodamine B. Propagation losses in the single mode waveguides, at 632.8 nm wavelength, were obtained.

  12. Improved DNA extraction efficiency from low level cell numbers using a silica monolith based micro fluidic device.

    Science.gov (United States)

    Kashkary, Loay; Kemp, Cordula; Shaw, Kirsty J; Greenway, Gillian M; Haswell, Stephen J

    2012-10-31

    The evaluation of a micro fluidic system with an integrated silica monolith for performing DNA extraction from limited biological samples has been carried out. Low DNA target concentrations usually require the addition of carrier RNA to ensure desired extraction efficiencies. Here, we demonstrate a micro fluidic extraction system with increasingly efficient extraction performances for biological samples containing extracted DNA showed successful amplification via the polymerase chain reaction demonstrating both the effectiveness of the proposed system at removing potential inhibitors and yielding good quality DNA. The work presented here beneficially identifies reduced sample volumes/concentrations as suitable for processing with respect to downstream analysis by enabling pre-concentration of the biological sample, particularly important when dealing with clinical or forensic specimens.

  13. Facile construction of macroporous hybrid monoliths via thiol-methacrylate Michael addition click reaction for capillary liquid chromatography.

    Science.gov (United States)

    Lin, Hui; Ou, Junjie; Liu, Zhongshan; Wang, Hongwei; Dong, Jing; Zou, Hanfa

    2015-01-30

    A facile approach based on thiol-methacrylate Michael addition click reaction was developed for construction of porous hybrid monolithic materials. Three hybrid monoliths were prepared via thiol-methacrylate click polymerization by using methacrylate-polyhedral oligomeric silsesquioxane (POSS) (cage mixture, n=8, 10, 12, POSS-MA) and three multi-thiol crosslinkers, 1,6-hexanedithiol (HDT), trimethylolpropane tris(3-mercaptopropionate) (TPTM) and pentaerythritol tetrakis(3-mercaptopropionate) (PTM), respectively, in the presence of porogenic solvents (n-propanol and PEG 200) and a catalyst (dimethylphenylphosphine, DMPP). The obtained monoliths possessed high thermal and chemical stabilities. Besides, they all exhibited high column efficiencies and excellent separation abilities in capillary liquid chromatography (cLC). The highest column efficiency could reach ca. 195,000N/m for butylbenzene on the monolith prepared with POSS-MA and TPTM (monolith POSS-TPTM) in reversed-phase (RP) mode at 0.64mm/s. Good chromatographic performance were all achieved in the separations of polycyclic aromatic hydrocarbons (PAHs), phenols, anilines, EPA 610 as well as bovine serum albumin (BSA) digest. The high column efficiencies in the range of 51,400-117,000N/m (achieved on the monolith POSS-PTM in RP mode) convincingly demonstrated the high separation abilities of these thiol-methacrylate based hybrid monoliths. All the results demonstrated the feasibility of the phosphines catalyzed thiol-methacrylate Michael addition click reaction in fabrication of monolithic columns with high efficiency for cLC applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Synthesis and characterization of guar gum templated hybrid nano silica.

    Science.gov (United States)

    Singh, V; Singh, S K; Pandey, S; Sanghi, R

    2011-08-01

    The objective of the present study was the fabrication of green adsorbent hybrids for which native guar gum was used as template to polymerize tetraethoxysilane. The properties and performances of the hybrids could be tailored by using varying molecular sizes of the partially depolymerized guar gum templates of various molecular sizes as control. Zn(II) uptake from aqueous solution was used as a criterion for evaluating the adsorbent efficiency. The optimum material (H4) in terms of maximum Zn(II) uptake, was obtained when the template size used was 375 kDa at a calcination temperature of 700°C. H4 was also evaluated for Ca(II), Mg(II), Cd(II) and Hg(II) adsorption. To explore the other applicability areas, the hybrids have been extensively characterized using FTIR, XRD, TGA-DTA, PL, SEM, TEM and BET analyses. H4 was found to be as efficient as previously reported vinyl modified-silica nanohybrids. It had a high surface area (264 m(2)/g) with silica nanoparticles in the size range of 90-140 nm. Being thermally very stable and photoluminescent, the material can be potentially used for many biological, medical and environmental applications.

  15. Towards waste free organic synthesis using nanostructured hybrid silicas

    Science.gov (United States)

    Ciriminna, Rosaria; Ilharco, Laura M.; Pandarus, Valerica; Fidalgo, Alexandra; Béland, François; Pagliaro, Mario

    2014-05-01

    As catalysis and organic synthesis come together again, the need for stable, selective and truly heterogeneous solid catalysts for clean and efficient synthetic organic chemistry has increased. Hybrid silica glasses obtained by the sol-gel nanochemistry approach can be successfully used for the waste-free synthesis of valued chemicals in various applications. This success derives from the deliberate chemical design of hybrid nanostructures capable of immobilizing and stabilizing organocatalytic species and unstable metal nanoparticles. The highly selective activity along with a broad scope and ease of application of these mesoporous materials to high-throughput reactions opens the route to faster, cleaner and more convenient processes for both small and large scale manufacturing of useful molecules.

  16. Preparation and characterization of polyimide/silica hybrid films

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ming-yan; ZENG Shu-jin; DONG Tie-quan; ZHOU Sheng; FAN Yong; ZHANG Xiao-hong; LEI Qing-quan

    2006-01-01

    A kind of hybrid polyimide films was prepared by synthesizing poly( amic acid ) /Silica matrix resin through sol-gel technique and then followed by positing it on a silex glass plate and drying at high temperature.The effect of silica content on the corona-resistant property of the films was studied. The miscibility between the organic and inorganic phases and its effect on the corona-resistant property were investigated with aminopropyltriethoxysilane, which served as a coupling agent, added into the polyimide composite system. The chemical structure and the surface morphology of the films were characterized by FTIR and AFM respectively. The corona-resistant property of the films was tested by a rod-plate electrode. It proved that the corona-resistant property was enhanced with silica content. It also turned ont that the improvement of the miscibility between the two phases due to the presence of covalent force as a result of the addition of the coupling agent had, to some extent,effect on the corona-resistant property of the films. Furthermore, a theory on the corona-resistant property was put forward preliminarily.

  17. Molecular Organization Induced Anisotropic Properties of Perylene – Silica Hybrid Nanoparticles

    OpenAIRE

    Sriramulu, Deepa; Turaga, Shuvan Prashant; Bettiol, Andrew Anthony; Valiyaveettil, Suresh

    2017-01-01

    Optically active silica nanoparticles are interesting owing to high stability and easy accessibility. Unlike previous reports on dye loaded silica particles, here we address an important question on how optical properties are dependent on the aggregation-induced segregation of perylene molecules inside and outside the silica nanoparticles. Three differentially functionalized fluorescent perylene - silica hybrid nanoparticles are prepared from appropriate ratios of perylene derivatives and tet...

  18. Preparation and characterization of silk/silica hybrid biomaterials by sol-gel crosslinking process

    Energy Technology Data Exchange (ETDEWEB)

    Hou Aiqin, E-mail: aiqinhou@dhu.edu.c [National Engineering Research Center for Dyeing and Finishing of Textiles, Donghua University, 3H, 2999 North Renmin Road, Songjiang, Shanghai 201620 (China); Chen Huawei [National Engineering Research Center for Dyeing and Finishing of Textiles, Donghua University, 3H, 2999 North Renmin Road, Songjiang, Shanghai 201620 (China)

    2010-03-15

    The silk/silica hybrid biomaterials are synthesized by sol-gel crosslinking process. The chemical and morphological structures of silk/silica hybrids are investigated with micro-FT-IR spectra, X-ray diffraction, SEM, AFM, and DSC. The results show that the crosslinking reactions among inorganic nano-particles, fibroin and 2,4,6-tri[(2-epihydrin-3-bimethyl-ammonium)propyl]-1,3,5-triazine chloride (Tri-EBAC) take place during sol-gel process. The silk/silica hybrids form new molecular structures containing not only organic fibroin but also inorganic nano-silica particles. The inorganic particles are bounded to the fibroin through covalent bonds. The silk/silica hybrids can form excellent film with very even nanometer particles. The thermal properties of organic/inorganic hybrid are improved.

  19. A multiply-add engine with monolithically integrated 3D memristor crossbar/CMOS hybrid circuit

    Science.gov (United States)

    Chakrabarti, B.; Lastras-Montaño, M. A.; Adam, G.; Prezioso, M.; Hoskins, B.; Cheng, K.-T.; Strukov, D. B.

    2017-02-01

    Silicon (Si) based complementary metal-oxide semiconductor (CMOS) technology has been the driving force of the information-technology revolution. However, scaling of CMOS technology as per Moore’s law has reached a serious bottleneck. Among the emerging technologies memristive devices can be promising for both memory as well as computing applications. Hybrid CMOS/memristor circuits with CMOL (CMOS + “Molecular”) architecture have been proposed to combine the extremely high density of the memristive devices with the robustness of CMOS technology, leading to terabit-scale memory and extremely efficient computing paradigm. In this work, we demonstrate a hybrid 3D CMOL circuit with 2 layers of memristive crossbars monolithically integrated on a pre-fabricated CMOS substrate. The integrated crossbars can be fully operated through the underlying CMOS circuitry. The memristive devices in both layers exhibit analog switching behavior with controlled tunability and stable multi-level operation. We perform dot-product operations with the 2D and 3D memristive crossbars to demonstrate the applicability of such 3D CMOL hybrid circuits as a multiply-add engine. To the best of our knowledge this is the first demonstration of a functional 3D CMOL hybrid circuit.

  20. A multiply-add engine with monolithically integrated 3D memristor crossbar/CMOS hybrid circuit

    Science.gov (United States)

    Chakrabarti, B.; Lastras-Montaño, M. A.; Adam, G.; Prezioso, M.; Hoskins, B.; Cheng, K.-T.; Strukov, D. B.

    2017-01-01

    Silicon (Si) based complementary metal-oxide semiconductor (CMOS) technology has been the driving force of the information-technology revolution. However, scaling of CMOS technology as per Moore’s law has reached a serious bottleneck. Among the emerging technologies memristive devices can be promising for both memory as well as computing applications. Hybrid CMOS/memristor circuits with CMOL (CMOS + “Molecular”) architecture have been proposed to combine the extremely high density of the memristive devices with the robustness of CMOS technology, leading to terabit-scale memory and extremely efficient computing paradigm. In this work, we demonstrate a hybrid 3D CMOL circuit with 2 layers of memristive crossbars monolithically integrated on a pre-fabricated CMOS substrate. The integrated crossbars can be fully operated through the underlying CMOS circuitry. The memristive devices in both layers exhibit analog switching behavior with controlled tunability and stable multi-level operation. We perform dot-product operations with the 2D and 3D memristive crossbars to demonstrate the applicability of such 3D CMOL hybrid circuits as a multiply-add engine. To the best of our knowledge this is the first demonstration of a functional 3D CMOL hybrid circuit. PMID:28195239

  1. Technological and Physical Compatibilities in Hybrid Integration of Laser and Monolithic Integration of Waveguide, Photodetector and CMOS Circuits on Silicon

    NARCIS (Netherlands)

    Zhou, M.J.; Ikkink, T.; Chalmers, J.; Kranenburg, H. van; Albers, H.; Holleman, J.; Lambeck, P.V.; Joppe, J.L.; Bekman, H.H.P.T.; Krijger, A.J.T. de

    1994-01-01

    In this paper, technological and physical compatibilities in hybrid integration of AlInGaP laser and monolithic integration of ZnO monomode waveguide, pin-photodetector, CMOS circuits for laser power control and signal amplification on silicon substrate are studied. Prospective problems and their po

  2. Technological and physical compatibilities in hybrid integration of laser and monolithic integration of waveguide, photodetector and CMOS circuits on silicon

    NARCIS (Netherlands)

    Zhou, Ming-Jiang; Ikkink, Ton; Chalmers, John; Kranenburg, van Herma; Albers, Hans; Holleman, Jisk; Lambeck, Paul; Joppe, Jan Leendert; Bekman, Herman; Krijger, de Ton; Lambeck, P.V.

    1994-01-01

    In this paper, technological and physical compatibilities in hybrid integration of AlInGaP laser and monolithic integration of ZnO monomode waveguide, pin-photodetector, CMOS circuits for laser power control and signal amplification on silicon substrate are studied. Prospective problems and their po

  3. Application of a Burkholderia cepacia lipase-immobilized silica monolith to batch and continuous biodiesel production with a stoichiometric mixture of methanol and crude Jatropha oil

    Directory of Open Access Journals (Sweden)

    Takahashi Ryo

    2011-10-01

    Full Text Available Abstract Background The enzymatic production of biodiesel through alcoholysis of triglycerides has become more attractive because it shows potential in overcoming the drawbacks of chemical processes. In this study, we investigate the production of biodiesel from crude, non-edible Jatropha oil and methanol to characterize Burkholderia cepacia lipase immobilized in an n-butyl-substituted hydrophobic silica monolith. We also evaluate the performance of a lipase-immobilized silica monolith bioreactor in the continuous production of biodiesel. Results The Jatropha oil used contained 18% free fatty acids, which is problematic in a base-catalyzed process. In the lipase-catalyzed reaction, the presence of free fatty acids made the reaction mixture homogeneous and allowed bioconversion to proceed to 90% biodiesel yield after a 12 hour reaction time. The optimal molar ratio of methanol to oil was 3.3 to 3.5 parts methanol to one part oil, with water content of 0.6% (w/w. Further experiments revealed that B. cepacia lipase immobilized in hydrophobic silicates was sufficiently tolerant to methanol, and glycerol adsorbed on the support disturbed the reaction to some extent in the present reaction system. The continuous production of biodiesel was performed at steady state using a lipase-immobilized silica monolith bioreactor loaded with 1.67 g of lipase. The yield of 95% was reached at a flow rate of 0.6 mL/h, although the performance of the continuous bioreactor was somewhat below that predicted from the batch reactor. The bioreactor was operated successfully for almost 50 days with 80% retention of the initial yield. Conclusions The presence of free fatty acids originally contained in Jatropha oil improved the reaction efficiency of the biodiesel production. A combination of B. cepacia lipase and its immobilization support, n-butyl-substituted silica monolith, was effective in the production of biodiesel. This procedure is easily applicable to the design

  4. Synthesis of robust hierarchical silica monoliths by surface-mediated solution/precipitation reactions over different scales: designing capillary microreactors for environmental applications.

    Science.gov (United States)

    García-Aguilar, J; Miguel-García, I; Berenguer-Murcia, Á; Cazorla-Amorós, D

    2014-12-24

    A synthetic procedure to prepare novel materials (surface-mediated fillings) based on robust hierarchical monoliths is reported. The methodology includes the deposition of a (micro- or mesoporous) silica thin film on the support followed by growth of a porous monolithic SiO2 structure. It has been demonstrated that this synthesis is viable for supports of different chemical nature with different inner diameters without shrinkage of the silica filling. The formation mechanism of the surface-mediated fillings is based on a solution/precipitation process and the anchoring of the silica filling to the deposited thin film. The interaction between the two SiO2 structures (monolith and thin film) depends on the porosity of the thin film and yields composite materials with different mechanical stability. By this procedure, capillary microreactors have been prepared and have been proved to be highly active and selective in the total and preferential oxidation of carbon monoxide (TOxCO and PrOxCO).

  5. Recent advances in multifunctional silica-based hybrid nanocarriers for bioimaging and cancer therapy

    Science.gov (United States)

    Lim, Wei Qi; Phua, Soo Zeng Fiona; Xu, Hesheng Victor; Sreejith, Sivaramapanicker; Zhao, Yanli

    2016-06-01

    In recent years, there has been a considerable research focus on integrating cancer cell imaging and therapeutic functions into single nanoscale platforms for better treatment of cancer. This task could often be achieved by incorporating multiple components into a hybrid nanosystem. In this minireview, we highlight different types of silica-based hybrid nanosystems and their recent applications as integrated multifunctional platforms for cancer imaging and treatment. The discussions are divided into several sections focusing on various types of materials employed to integrate with silica, which include silica-metallic nanoparticle based hybrid nanocarriers, silica-gold nanoparticle based hybrid nanocarriers, silica-quantum dot based hybrid nanocarriers, silica-upconversion nanoparticle based hybrid nanocarriers, silica-carbon based hybrid nanocarriers, and organosilica nanocarriers. Therapeutic agents loaded in such hybrids include chemodrugs, proteins, DNA/RNA and photosensitizers. For targeted delivery into tumor sites, targeting ligands such as antibodies, peptides, aptamers, and other small molecules are grafted on the surface of the nanocarriers. At the end of the review, a brief summary and research outlook are presented. This minireview aims to provide a quick update of recent research achievements in the field.

  6. Synthesis of a SiO2/TiO2 hybrid boronate affinity monolithic column for specific capture of glycoproteins under neutral conditions.

    Science.gov (United States)

    Yang, Qin; Huang, Dihui; Zhou, Ping

    2014-03-07

    A unique boronate-functionalized SiO2/TiO2 hybrid monolithic column was synthesized by a facile approach. Although a conventional boronic acid, 4-vinylphenylboronic acid, was used as the affinity ligand, the prepared monolithic column exhibited specific capacity to capture glycoproteins including antibodies in aqueous solution at neutral pH. With the incorporation of titania, the monolith was highly hydrophilic, and the procedure of affinity chromatography could be performed under aqueous organic-solvent-free conditions.

  7. Continuous laser direct-writing of PbS nanoparticles inside transparent silica monoliths

    Science.gov (United States)

    Chahadih, Abdallah; El Hamzaoui, Hicham; Bernard, Rémy; Bois, Laurence; Beclin, Franc; Cristini, Odile; Capoen, Bruno; Bouazaoui, Mohamed

    2011-12-01

    Direct space-selective growth of PbS nanoparticles, embedded inside a transparent porous sol-gel derived silica matrix, has been achieved using continuous laser irradiation. Before the irradiation, the porous silica host has been soaked in a PbS precursor solution. The effect of the concentration of PbS precursors and of the incident laser power on the mean particle size was studied. Absorption spectroscopy, X-ray diffraction analysis, and TEM measurements were used to identify the PbS crystallites inside the xerogel and to estimate the average particle size. It has been shown that PbS crystallite sizes range between 3 and 13 nm depending on the PbS precursors concentration.

  8. Hybrid silica luminescent materials based on lanthanide-containing lyotropic liquid crystal with polarized emission

    Energy Technology Data Exchange (ETDEWEB)

    Selivanova, N.M., E-mail: natsel@mail.ru [Kazan National Research Technological University, 68 Karl Marx Str., Kazan 420015 (Russian Federation); Vandyukov, A.E.; Gubaidullin, A.T. [A.E. Arbuzov Institute of Organic and Physical Chemistry of the Kazan Scientific Center of the Russian Academy of Sciences, 8 Acad. Arbuzov Str., Kazan 420088 (Russian Federation); Galyametdinov, Y.G. [Kazan National Research Technological University, 68 Karl Marx Str., Kazan 420015 (Russian Federation)

    2014-11-14

    This paper represents the template method for synthesis of hybrid silica films based on Ln-containing lyotropic liquid crystal and characterized by efficient luminescence. Luminescence films were prepared in situ by the sol–gel processes. Lyotropic liquid crystal (LLC) mesophases C{sub 12}H{sub 25}O(CH{sub 2}CH{sub 2}O){sub 10}H/Ln(NO{sub 3}){sub 3}·6H{sub 2}O/H{sub 2}O containing Ln (III) ions (Dy, Tb, Eu) were used as template. Polarized optical microscopy, X-ray powder diffraction, and FT-IR-spectroscopy were used for characterization of liquid crystal mesophases and hybrid films. The morphology of composite films was studied by the atomic force microscopy method (AFM). The optical properties of the resulting materials were evaluated. It was found that hybrid silica films demonstrate significant increase of their lifetime in comparison with an LLC system. New effects of linearly polarized emission revealed for Ln-containing hybrid silica films. Polarization in lanthanide-containing hybrid composites indicates that silica precursor causes orientation of emitting ions. - Highlights: • We suggest a new simple approach for creating luminescence hybrid silica films. • Ln-containing hybrid silica films demonstrate yellow, green and red emissions. • Tb(III)-containing hybrid film have a high lifetime. • We report effects of linearly polarized emission in hybrid film.

  9. Novel bioactive materials: silica aerogel and hybrid silica aerogel/pseudowollastonite

    Directory of Open Access Journals (Sweden)

    Reséndiz-Hernández, P. J.

    2014-10-01

    Full Text Available Silica aerogel and hybrid silica aerogel/pseudowollastonite materials were synthesized by controlled hydrolysis of tetraethoxysilane (TEOS using also methanol (MeOH and pseudowollastonite particles. The gels obtained were dried using a novel process based on an ambient pressure drying. Hexane and hexamethyl-disilazane (HMDZ were the solvents used to chemically modify the surface. In order to assess bioactivity, aerogels, without and with pseudowollastonite particles, were immersed in simulated body fluid (SBF for 7 and 14 days. The hybrid silica aerogel/pseudowollastonite showed a higher bioactivity than that observed for the single silica aerogel. However, as in both cases a lower bioactivity was observed, a biomimetic method was also used to improve it. In this particular method, samples of both materials were immersed in SBF for 7 days followed by their immersion in a more concentrated solution (1.5 SBF for 14 days. A thick and homogeneous bonelike apatite layer was formed on the biomimetically treated materials. Thus, bioactivity was successfully improved even on the aerogel with no pseudowollastonite particles. As expected, the hybrid silica aerogel/pseudowollastonite particles showed a higher bioactivity.Se sintetizaron aerogel de sílice y aerogel híbrido de sílice/partículas de pseudowollastonita por hidrólisis controlada de tetraetoxisilano (TEOS usando metanol (MeOH y partículas de pseudowollastonita. Los geles obtenidos se secaron utilizando un novedoso proceso basado en una presión de secado ambiental. Hexano y hexametil-disilazano fueron los solventes usados para modificar químicamente la superficie. Para evaluar la bioactividad, los aerogeles con y sin partículas de pseudowollastonita se sumergieron en un fluido fisiológico simulado (SBF por 7 y 14 días. El aerogel híbrido de sílice/partículas de pseudowollastonita mostró más alta bioactividad que la observada por el aerogel solo. Sin embargo, en ambos casos, se

  10. Silica-based monolithic column with evaporative light scattering detector for HPLC analysis of bacosides and apigenin in Bacopa monnieri.

    Science.gov (United States)

    Bhandari, Pamita; Kumar, Neeraj; Singh, Bikram; Singh, Virendra; Kaur, Inderjeet

    2009-08-01

    A high performance liquid chromatographic method using a silica-based monolithic column coupled with evaporative light scattering detector (HPLC-ELSD) was developed and validated for simultaneous quantification of bacosides (bacoside A, bacopaside I, bacoside A(3), bacopaside II, bacopaside X, bacopasaponin C) and apigenin in Bacopa monnieri. The chromatographic resolution was achieved on a Chromolith RP-18 (100x4.6 mm) column with acetonitrile/water (30:70) as mobile phase in isocratic elution at a flow rate of 0.7 mL/min. The drift tube temperature of the ELSD was set to 95 degrees C, and the nitrogen flow rate was 2.0 SLM (standard liter per minute). The calibration curves revealed a good linear relationship (r(2) > 0.9988) within the test ranges. The detection limits (S/N = 3) and the quantification limits (S/N = 10) for the compounds were in the range of 0.54-6.06 and 1.61-18.78 microg/mL, respectively. Satisfactory average recovery was observed in the range of 95.8-99.0%. The method showed good reproducibility for the quantification of these compounds in B. monnieri with intra- and inter-day precision of less than 0.69 and 0.67%, respectively. The validated method was successfully applied to quantify analytes in nine accessions of B. monnieri and thus provides a new basis for overall quality assessment of B. monnieri.

  11. Development of a novel starch-derived porous silica monolith for enhancing the dissolution rate of poorly water soluble drug

    Energy Technology Data Exchange (ETDEWEB)

    Wu Chao; Wang Jing; Hu Yanchen [Department of Pharmaceutics, Shenyang Pharmaceutical University P.O. Box 32, 103 Wenhua Road, Shenhe District, Shenyang, Liaoning Province 110016 (China); Zhi Zhuangzhi [Department of Physics, School of Basic Science, Shenyang Pharmaceutical University, Wenhua Road 103, Shenyang, Liaoning 110016 (China); Jiang Tongying [Department of Pharmaceutics, Shenyang Pharmaceutical University P.O. Box 32, 103 Wenhua Road, Shenhe District, Shenyang, Liaoning Province 110016 (China); Zhang Jinghai [Key laboratory of Pharmaceutical Biotechnology, School of Life Science and Bio- Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016 (China); Wang Siling, E-mail: silingwang@hotmail.com [Department of Pharmaceutics, Shenyang Pharmaceutical University P.O. Box 32, 103 Wenhua Road, Shenhe District, Shenyang, Liaoning Province 110016 (China)

    2012-02-01

    A novel starch-derived porous silica monolith (PSM) and porous starch foam (PSF) were developed as a carrier in order to improve the dissolution of lovastatin. PSM was prepared by the starch gel template method and PSF was prepared by the solvent exchange method. The morphology and structure of PSM and PSF were characterized by scanning electron microscopy (SEM) and nitrogen adsorption/desorption analysis. Lovastatin was loaded into PSM and PSF by immersion/solvent evaporation. Nano-pore spatial confinement effect on the drug dissolution was systematically studied by SEM, Fourier transform infrared spectroscopy (FTIR), thermogravametric analysis (TGA), x-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), and in-vitro drug dissolution studies. Lovastatin adsorbed in PSM was amorphous and lovastatin absorbed on PSF was partially present as microcrystal in the pores of PSF and partially in crystalline form distributed on the surface of PSF. PSM and PSF allowed immediate release of lovastatin and enhanced the dissolution rate. These results provide important information about the mechanism of drug adsorption and release. Accordingly, PSM and PSF have a promising future as a vehicle for the oral delivery of poorly water soluble drugs. Moreover, the effect of PSM is better than that of PSF.

  12. Crack-free polydimethylsiloxane-bioactive glass-poly(ethylene glycol) hybrid monoliths with controlled biomineralization activity and mechanical property for bone tissue regeneration.

    Science.gov (United States)

    Chen, Jing; Du, Yuzhang; Que, Wenxiu; Xing, Yonglei; Chen, Xiaofeng; Lei, Bo

    2015-12-01

    Crack-free organic-inorganic hybrid monoliths with controlled biomineralization activity and mechanical property have an important role for highly efficient bone tissue regeneration. Here, biomimetic and crack-free polydimethylsiloxane (PDMS)-modified bioactive glass (BG)-poly(ethylene glycol) (PEG) (PDMS-BG-PEG) hybrids monoliths were prepared by a facile sol-gel technique. Results indicate that under the assist of co-solvents, BG sol and PDMS and PEG could be hybridized at a molecular level, and effects of the PEG molecular weight on the structure, biomineralization activity, and mechanical property of the as-prepared hybrid monoliths were also investigated in detail. It is found that an addition of low molecular weight PEG can significantly prevent the formation of cracks and speed up the gelation of the hybrid monoliths, and the surface microstructure of the hybrid monoliths can be changed from the porous to the smooth as the PEG molecular weight increases. Additionally, the hybrid monoliths with low molecular weight PEG show the high formation of the biological apatite layer, while the hybrids with high molecular weight PEG exhibit negligible biomineralization ability in simulated body fluid (SBF). Furthermore, the PDMS-BG-PEG 600 hybrid monolith has significantly high compressive strength (32 ± 3 MPa) and modulus (153 ± 11 MPa), as well as good cell biocompatibility by supporting osteoblast (MC3T3-E1) attachment and proliferation. These results indicate that the as-prepared PDMS-BG-PEG hybrid monoliths may have promising applications for bone tissue regeneration.

  13. Synthesis of biocompatible hydrophobic silica-gelatin nano-hybrid by sol-gel process.

    Science.gov (United States)

    Smitha, S; Shajesh, P; Mukundan, P; Nair, T D R; Warrier, K G K

    2007-03-15

    Silica-biopolymer hybrid has been synthesised using colloidal silica as the precursor for silica and gelatin as the biopolymer counterpart. The surface modification of the hybrid material has been done with methyltrimethoxysilane leading to the formation of biocompatible hydrophobic silica-gelatin hybrid. Here we are reporting hydrophobic silica-gelatin hybrid and coating precursor for the first time. The hybrid gel has been evaluated for chemical modification, thermal degradation, hydrophobicity, particle size, transparency under the UV-visible region and morphology. FTIR spectroscopy has been used to verify the presence of CH(3) groups which introduce hydrophobicity to the SiO2-MTMS-gelatin hybrids. The hydrophobic property has also been tailored by varying the concentration of methyltrimethoxysilane. Contact angle by Wilhelmy plate method of transparent hydrophobic silica-gelatin coatings has been found to be as high as approximately 95 degrees . Oxidation of the organic group which induces the hydrophobic character occurs at 530 degrees C which indicates that the surface hydrophobicity is retained up to that temperature. Optical transmittance of SiO2-MTMS-gelatin hybrid coatings on glass substrates has been found to be close to 100% which will enable the hybrid for possible optical applications and also for preparation of transparent biocompatible hydrophobic coatings on biological substrates such as leather.

  14. Facile synthesis and application of poly(ionic liquid)-bonded silica hybrid materials.

    Science.gov (United States)

    Bi, Wentao; Tian, Minglei; Row, Kyung Ho

    2012-05-07

    Facile methods were developed to prepare hybrid poly(ionic liquid)-bonded silica for a wide range of applications, particularly in analytical chemistry. The hybrid material obtained was evaluated by comparing its adsorption capacity with other conventional separation materials. In addition, the hybrid material has the potential for industrial scale production.

  15. Polystyrene-Core-Silica-Shell Hybrid Particles Containing Gold and Magnetic Nanoparticles.

    Science.gov (United States)

    Tian, Jia; Vana, Philipp

    2016-02-18

    Polystyrene-core-silica-shell hybrid particles were synthesized by combining the self-assembly of nanoparticles and the polymer with a silica coating strategy. The core-shell hybrid particles are composed of gold-nanoparticle-decorated polystyrene (PS-AuNP) colloids as the core and silica particles as the shell. PS-AuNP colloids were generated by the self-assembly of the PS-grafted AuNPs. The silica coating improved the thermal stability and dispersibility of the AuNPs. By removing the "free" PS of the core, hollow particles with a hydrophobic cage having a AuNP corona and an inert silica shell were obtained. Also, Fe3O4 nanoparticles were encapsulated in the core, which resulted in magnetic core-shell hybrid particles by the same strategy. These particles have potential applications in biomolecular separation and high-temperature catalysis and as nanoreactors.

  16. Reinforcement of natural rubber hybrid composites based on marble sludge/Silica and marble sludge/rice husk derived silica

    Directory of Open Access Journals (Sweden)

    Khalil Ahmed

    2014-03-01

    Full Text Available A research has been carried out to develop natural rubber (NR hybrid composites reinforced with marble sludge (MS/Silica and MS/rice husk derived silica (RHS. The primary aim of this development is to scrutinize the cure characteristics, mechanical and swelling properties of such hybrid composite. The use of both industrial and agricultural waste such as marble sludge and rice husk derived silica has the primary advantage of being eco-friendly, low cost and easily available as compared to other expensive fillers. The results from this study showed that the performance of NR hybrid composites with MS/Silica and MS/RHS as fillers is extremely better in mechanical and swelling properties as compared with the case where MS used as single filler. The study suggests that the use of recently developed silica and marble sludge as industrial and agricultural waste is accomplished to provide a probable cost effective, industrially prospective, and attractive replacement to the in general purpose used fillers like china clay, calcium carbonate, and talc.

  17. Chelation ion chromatography of alkaline earth and transition metals a using monolithic silica column with bonded N-hydroxyethyliminodiacetic acid functional groups.

    Science.gov (United States)

    McGillicuddy, Nicola; Nesterenko, Ekaterina P; Nesterenko, Pavel N; Jones, Phil; Paull, Brett

    2013-02-08

    A commercially available porous silica monolithic column (Onyx Monolithic Si, 100 mm×4.6 mm I.D.) was 'in-column' covalently functionalised with 2-hydroxyethyliminodiacetic acid (HEIDA) groups, and applied to the simultaneous and rapid separation of alkaline earth and transition metal ions, using high-performance chelation ion chromatography (HPCIC). With a 0.3mM dipicolinic acid (DPA) containing eluent, the baseline separation of various common transition and heavy metal ions and the four alkaline earth metal ions could be achieved in under 14 min with a flow rate of just 0.8 mL/min. Detection was achieved using spectrophotometric detection at 540 nm after post-column reaction (PCR) with 4-(2-pyridylazo)-resorcinol (PAR). Significant effects from variation of eluent nature, concentration and temperature upon selectivity and retention were demonstrated with the new monolithic silica chelating phase. Under optimised conditions (0.165 M LiNO(3) eluent, pH 2.5), peak efficiencies of 54,000, 60,000 and 64,000 N/m, for Zn(2+), Mn(2+) and Cd(2+), respectively, were recorded, far exceeding that previously reported for IDA based chelation ion exchange columns.

  18. Development of a bi-functional silica monolith for electro-osmotic pumping and DNA clean-up/extraction using gel-supported reagents in a microfluidic device.

    Science.gov (United States)

    Oakley, Jennifer A; Shaw, Kirsty J; Docker, Peter T; Dyer, Charlotte E; Greenman, John; Greenway, Gillian M; Haswell, Stephen J

    2009-06-07

    A silica monolith used to support both electro-osmotic pumping (EOP) and the extraction/elution of DNA coupled with gel-supported reagents is described. The benefits of the combined EOP extraction/elution system were illustrated by combining DNA extraction and gene amplification using the polymerase chain reaction (PCR) process. All the reagents necessary for both processes were supported within pre-loaded gels that allow the reagents to be stored at 4 degrees C for up to four weeks in the microfluidic device. When carrying out an analysis the crude sample only needed to be hydrodynamically introduced into the device which was connected to an external computer controlled power supply via platinum wire electrodes. DNA was extracted with 65% efficiency after loading lysed cells onto a silica monolith. Ethanol contained within an agarose gel matrix was then used to wash unwanted debris away from the sample by EOP (100 V cm(-1) for 5 min). The retained DNA was subsequently eluted from the monolith by water contained in a second agarose gel, again by EOP using an electric field of 100 V cm(-1) for 5 min, and transferred into the PCR reagent containing gel. The eluted DNA in solution was successfully amplified by PCR, confirming that the concept of a complete self-contained microfluidic device could be realised for DNA sample clean up and amplification, using a simple pumping and on-chip reagent storage methodology.

  19. Preparation and characterization of silica monolith modified with bovine serum albumin-gold nanoparticles conjugates and its use as chiral stationary phases for capillary electrochromatography.

    Science.gov (United States)

    Lu, Junyu; Ye, Fanggui; Zhang, Aizhu; Wei, Zong; Peng, Yan; Zhao, Shulin

    2011-08-01

    This paper describes the development of silica monolith modified with bovine serum albumin-gold nanoparticles (BSA-GNPs) conjugates as chiral stationary phases for capillary electrochromatography (CEC). The bare monolithic silica column was prepared by a sol-gel process and has been modified chemically with 3-mercaptopropyltrimethoxysilane to provide thiol groups, followed by immobilization of gold nanoparticles via the formation of an Au-S bond and modification with BSA as the chiral selector via the nitrogen lone pair of electrons. It has been demonstrated that the monolithic chiral stationary phases can be used for the enantioseparation of a number of phenylthiocarbamyl amino acids (PTC-D/L-AAs) by CEC. Ten pairs of tested amino acids enantiomers were successfully resolved within 18 min under optimized conditions, and the resolution values were in the range of 1.486-2.083. With PTC-D/L-tryptophan used as the probe solute, the influences of applied voltage, organic modifier and buffer pH in mobile phase on apparent retention factor, enantioselectivity and resolution factor were also investigated.

  20. Preparation and characterization of uniformly sized sub-micrometer spherical silica/organic polymer hybrid particles

    Energy Technology Data Exchange (ETDEWEB)

    Xing, X.-S.; Li, R.K.Y.; Shek, C.-H. [Department of Physics and Materials Science, City University of Hong Kong, Tak Chee Avenue, Kowloon, Hong Kong (China)

    2003-09-01

    Hybrid particles with a core-shell structure, consisting of a silica core and a polyvinyl alcohol (PVA) shell were fabricated via a two-step sol-gel process. The PVA molecular chains are probably physically adsorbed onto the surface of silica cores by hydrogen bonds and van der Waals forces. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  1. Characterization and Curing Kinetics of Epoxy/Silica Nano-Hybrids

    Directory of Open Access Journals (Sweden)

    Cheng-Fu Yang

    2015-10-01

    Full Text Available The sol-gel technique was used to prepare epoxy/silica nano-hybrids. The thermal characteristics, curing kinetics and structure of epoxy/silica nano-hybrids were studied using differential scanning calorimetry (DSC, 29Si nuclear magnetic resonance (NMR and transmission electron microscopy (TEM. To improve the compatibility between the organic and inorganic phases, a coupling agent was used to modify the diglycidyl ether of bisphenol A (DGEBA epoxy. The sol-gel technique enables the silica to be successfully incorporated into the network of the hybrids, increasing the thermal stability and improving the mechanical properties of the prepared epoxy/silica nano-hybrids. An autocatalytic mechanism of the epoxy/SiO2 nanocomposites was observed. The low reaction rate of epoxy in the nanocomposites is caused by the steric hindrance in the network of hybrids that arises from the consuming of epoxide group in the network of hybrids by the silica. In the nanocomposites, the nano-scale silica particles had an average size of approximately 35 nm, and the particles were well dispersed in the epoxy matrix, according to the TEM images.

  2. Characterization and Curing Kinetics of Epoxy/Silica Nano-Hybrids

    Science.gov (United States)

    Yang, Cheng-Fu; Wang, Li-Fen; Wu, Song-Mao; Su, Chean-Cheng

    2015-01-01

    The sol-gel technique was used to prepare epoxy/silica nano-hybrids. The thermal characteristics, curing kinetics and structure of epoxy/silica nano-hybrids were studied using differential scanning calorimetry (DSC), 29Si nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM). To improve the compatibility between the organic and inorganic phases, a coupling agent was used to modify the diglycidyl ether of bisphenol A (DGEBA) epoxy. The sol-gel technique enables the silica to be successfully incorporated into the network of the hybrids, increasing the thermal stability and improving the mechanical properties of the prepared epoxy/silica nano-hybrids. An autocatalytic mechanism of the epoxy/SiO2 nanocomposites was observed. The low reaction rate of epoxy in the nanocomposites is caused by the steric hindrance in the network of hybrids that arises from the consuming of epoxide group in the network of hybrids by the silica. In the nanocomposites, the nano-scale silica particles had an average size of approximately 35 nm, and the particles were well dispersed in the epoxy matrix, according to the TEM images. PMID:28793616

  3. Shape Memory Properties of PBS-Silica Hybrids

    Directory of Open Access Journals (Sweden)

    Katia Paderni

    2014-01-01

    Full Text Available A series of novel Si–O–Si crosslinked organic/inorganic hybrid semi-crystalline polymers with shape memory properties was prepared from alkoxysilane-terminated poly(butylene succinate (PBS by water-induced silane crosslinking under organic solvent-free and catalyst-free conditions. The hydrolyzation and condensation of alkoxysilane end groups allowed for the generation of silica-like crosslinking points between the polymeric chains, acting not only as chemical net-points, but also as inorganic filler for a reinforcement effect. The resulting networks were characterized using differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, dynamic-mechanical analysis (DMA and tensile and shape memory tests to gain insight into the relationship between the polymeric structure, the morphology and the properties. By controlling the molecular weight of the PBS precursor, a fine tuning of the crosslinking density and the inorganic content of the resulting network was possible, leading to different thermal, mechanical and shape memory properties. Thanks to their suitable morphology consisting of crystalline domains, which represent the molecular switches between the temporary and permanent shapes, and chemical net-points, which permit the shape recovery, the synthesized materials showed good shape memory characteristics, being able to fix a significant portion of the applied strain in a temporary shape and to restore their original shape above their melting temperature.

  4. Monolithic III-V and hybrid polysilicon-III-V microelectromechanical tunable vertical-cavity surface-emitting lasers

    Science.gov (United States)

    Ochoa, Edward M.; Lott, James A.; Nelson, Thomas R., Jr.; Harvey, M. C.; Raley, J. A.; Stintz, Andreas; Malloy, Kevin J.

    2003-04-01

    We report our progress on the design and fabrication of electrostatically-actuated microelectromechanical (MEM) tunable wavelength filters and vertical cavity surface-emitting lasers (VCSELs). We investigate both an all-semiconductor monolithic approach and a hybrid approach based on the combination of conventional polysilicon microelectromechanical systems (MEMS) and III-V semiconductor thin-film distributed Bragg reflector (DBR) and VCSEL structures. In the tunable hybrid structures the III-V semiconductor layers are flip-bonded onto specially designed polysilicon foundry MEMS structures and separated from their lattice-matched parent substrates by a novel post-bonding lift-off process.

  5. Preparation of well-defined polystyrene/silica hybrid nanoparticles by ATRP

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Immobilization of the atom transfer radical polymerization(ATRP)macroinitiators at the silica nanoparticle surfaces was achieved through surface modification with excess toluene-2,4-diisocynate(TDI),after which the residual isocyanate groups were converted into ATRP macroinitiators.Structurally well-defined polystyrene chains were grown from the nanoparticle surfaces to yield individual particles composed of a silica core and a well-defined,densely grafted outer polystyrene by ATRP,which was initiated by the as-synthesized silica-based macroinitiator.FTIR,NMR and gel permeation chromatography(GPC)were used to characterize the polystyrene/silica hybrid particles.

  6. Preparation of well-defined polystyrene/silica hybrid nanoparticles by ATRP

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Immobilization of the atom transfer radical polymerization (ATRP) macroinitiators at the silica nanoparticle surfaces was achieved through surface modification with excess toluene-2,4-diisocynate (TDI), after which the residual isocyanate groups were converted into ATRP macroinitiators. Structurally well-defined polystyrene chains were grown from the nanoparticle surfaces to yield individual particles composed of a silica core and a well-defined, densely grafted outer polystyrene by ATRP, which was initiated by the as-synthesized silica-based macroinitiator. FTIR, NMR and gel permeation chro-matography (GPC) were used to characterize the polystyrene/silica hybrid particles.

  7. Effect of the presence of an ordered micro-pillar array on the formation of silica monoliths

    NARCIS (Netherlands)

    Detobel, Frederik; Eghbali, Hamed; De Bruyne, Selm; Terryn, Herman; Gardeniers, Han; Desmet, Gert

    2009-01-01

    We report on the synthesis of siloxane-based monoliths in the presence of a two-dimensional, perfectly ordered array of micro-pillars. Both methyltrimethoxysilane- and tetramethoxysilane-based monoliths were considered. The obtained structures were analyzed using scanning-electron microscopy and can

  8. Preparation and modification of polyhedral oligomeric silsesquioxane-containing hybrid monolithic capillary columns%含多面体低聚倍半硅氧烷杂化毛细管整体柱的制备及修饰

    Institute of Scientific and Technical Information of China (English)

    欧俊杰; 林辉; 刘哲益; 张振宾; 董靖; 邹汉法

    2013-01-01

    Two kinds of hybrid monolithic capillary columns were prepared via free radical polymerization. First, the hybrid monolithic column was in situ fabricated by using two polyhedral oligomeric silsesquioxanes (POSS) , POSS-methacryl substituted ( cage mixture, n = 8 , 10, 12) (POSS-MA) and POSS-( 1-propylmethacrylate )-heptaisobutyl substituted ( Bu-POSS ) , as crosslinker and monomer, respectively, in the presence of porogenic solvents ( propanol/ PEG400) and initiator (azodisobutyronitrile). Second, the hybrid monolithic column was similarly prepared by using POSS-MA, as sole monomer under the same conditions. The resulting two kinds of hybrid monolithic columns, poly( Bu-POSS-co-POSS-MA) and poly ( POSS-MA) , were characterized and applied for the separation of alkylbenzenes by capillary liquid chroma-tography (cLC) , showing good mechanical stability and reproducibility. Additionally, the poly (POSS-MA) monolith could be easily modified with other organic monomers, such as stearyl methacrylate (SMA) and benzyl metacrylate (BeMA) , with the presence of methacryl groups on the surface of the poly( POSS-MA) monolith. Compared with the raw poly( POSS-MA) monolith, the post-modified poly (POSS-MA) monolith exhibited higher column efficiency and better selectivity. This simple process of using POSS reagents via free radical polymerization is providing a novel way for the preparation of the organic-silica hybrid monolithic columns.%本文采用自由基聚合法原位制备了两种杂化毛细管整体柱.首先以含有一个甲基丙烯酸基团的多面体低聚倍半硅氧烷(POSS)试剂(Bu-POSS)为单体、以含有多个甲基丙烯酸基团的POSS试剂(POSS-MA)为交联剂在二元致孔剂(正丙醇/聚乙二醇400)和引发剂(偶氮二异丁腈)存在下发生热引发聚合,在毛细管中形成聚(Bu-POSS-co-POSS-MA)杂化整体柱;另外仅以POSS-MA为单体在相同条件下制备聚(POSS-MA)杂化整体柱,并将这两种杂化整体柱应用于小

  9. Synthesis, characterization and catalytic activity of carbon-silica hybrid catalyst from rice straw

    Science.gov (United States)

    Janaun, J.; Safie, N. N.; Siambun, N. J.

    2016-07-01

    The hybrid-carbon catalyst has been studied because of its promising potential to have high porosity and surface area to be used in biodiesel production. Silica has been used as the support to produce hybrid carbon catalyst due to its mesoporous structure and high surface area properties. The chemical synthesis of silica-carbon hybrid is expensive and involves more complicated preparation steps. The presence of natural silica in rice plants especially rice husk has received much attention in research because of the potential as a source for solid acid catalyst synthesis. But study on rice straw, which is available abundantly as agricultural waste is limited. In this study, rice straw undergone pyrolysis and functionalized using fuming sulphuric acid to anchor -SO3H groups. The presence of silica and the physiochemical properties of the catalyst produced were studied before and after sulphonation. The catalytic activity of hybrid carbon silica acid catalyst, (H-CSAC) in esterification of oleic acid with methanol was also studied. The results showed the presence of silica-carbon which had amorphous structure and highly porous. The carbon surface consisted of higher silica composition, had lower S element detected as compared to the surface that had high carbon content but lower silica composition. This was likely due to the fact that Si element which was bonded to oxygen was highly stable and unlikely to break the bond and react with -SO3H ions. H-CSAC conversions were 23.04 %, 35.52 % and 34.2 7% at 333.15 K, 343.15 K and 353.15 K, respectively. From this research, rice straw can be used as carbon precursor to produce hybrid carbon-silica catalyst and has shown catalytic activity in biodiesel production. Rate equation obtained is also presented.

  10. Hybrid thin films derived from UV-curable acrylate-modified waterborne polyurethane and monodispersed colloidal silica

    Directory of Open Access Journals (Sweden)

    C. H. Yang

    2012-01-01

    Full Text Available Hybrid thin films containing nano-sized inorganic domains were synthesized from UV-curable acrylate-modified waterborne polyurethane (WPU-AC and monodispersed colloidal silica with coupling agent. The coupling agent, 3-(trimethoxysilylpropyl methacrylate (MSMA, was bonded onto colloidal silica first, and then mixed with WPU-AC to form a precursor solution. This precursor was spin coated, dried and UV-cured to generate the hybrid films. The silica content in the hybrid thin films was varied from 0 to 30 wt%. Experimental results showed the aggregation of silica particles in the hybrid films. Thus, the silica domain in the hybrid films was varied from 30 to 50 nm by the different ratios of MSMAsilica to WPU-AC. The prepared hybrid films from the crosslinked WPU-AC/MSMA-silica showed much better thermal stability and mechanical properties than pure WPU-AC.

  11. Properties and Application Perspective of Hybrid Titania-Silica Patterns Fabricated by Inkjet Printing.

    Science.gov (United States)

    Dzik, Petr; Veselý, Michal; Kete, Marko; Pavlica, Egon; Štangar, Urška Lavrenčič; Neumann-Spallart, Michael

    2015-08-01

    A hybrid titania-silica cold-setting sol has been developed that can be deposited onto a wide variety of surfaces without the need for high-temperature fixing and that is suitable for material printing deposition. Thin hybrid titania-silica coatings were patterned onto glass and PET substrates by inkjet printing. Well-defined hybrid titania-silica patterns, with thicknesses ranging from 40 to 400 nm, were fabricated by overprinting 1 to 10 layers. Excellent mechanical, optical, and photocatalytic properties were observed, making the reported material well suited for the fabrication of transparent self-cleaning coatings both on mineral and organic substrates. The printed patterns exhibit photoelectrochemical activity that can be further improved by thermal or photonic curing. A concept of fully printed interdigitated photoelectrochemical cells on flexible PET substrates utilizing the reported hybrid photocatalyst is disclosed as well.

  12. Monolithic silica spin column extraction and simultaneous derivatization of amphetamines and 3,4-methylenedioxyamphetamines in human urine for gas chromatographic-mass spectrometric detection.

    Science.gov (United States)

    Nakamoto, Akihiro; Nishida, Manami; Saito, Takeshi; Kishiyama, Izumi; Miyazaki, Shota; Murakami, Katsunori; Nagao, Masataka; Namura, Akira

    2010-02-19

    A simple, sensitive, and specific method with gas chromatography-mass spectrometry was developed for simultaneous extraction and derivatization of amphetamines (APs) and 3,4-methylenedioxyamphetamines (MDAs) in human urine by using a monolithic silica spin column. All the procedures, such as sample loading, washing, and elution were performed by centrifugation. APs and MDAs in urine were adsorbed on the monolithic silica and derivatized with propyl chloroformate in the column. Methamphetamine-d(5) was used as an internal standard. The linear ranges were 0.01-5.0 microg mL(-1) for methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA) and 0.02-5.0 microg mL(-1) for amphetamine (AP) and 3,4-methylenedioxyamphetamine (MDA) (coefficient of correlation > or = 0.995). The recovery of APs and MDAs in urine was 84-94%, and the relative standard deviation of the intra- and interday reproducibility for urine samples containing 0.1, 1.0, and 4.0 microg mL(-1) of APs and MDAs ranged from 1.4% to 13.6%. The lowest detection limit (signal-to-noise ratio > or = 3) in urine was 5 ng mL(-1) for MA and MDMA and 10 ng mL(-1) for AP and MDA. The proposed method can be used to perform simultaneous extraction and derivatization on spin columns that have been loaded with a small quantity of solvent by using centrifugation.

  13. Preparation and evaluation of open tubular C18-silica monolithic microcartridges for preconcentration of peptides by on-line solid phase extraction capillary electrophoresis.

    Science.gov (United States)

    Ortiz-Villanueva, Elena; Benavente, Fernando; Giménez, Estela; Yilmaz, Fatma; Sanz-Nebot, Victoria

    2014-10-10

    In this study, C18-silica monoliths were synthesized as a porous layer in open tubular capillary columns, to be cut later into microcartridges for the analysis of neuropeptides by on-line solid-phase extraction capillary electrophoresis with UV and MS detection (SPE-CE-UV and SPE-CE-MS). First, several types of C18-silica monolithic (MtC18) microcartridges were used to analyse standard solutions of five neuropeptides (i.e. dynorphin A (1-7), substance P (7-11), endomorphin 1, methionine enkephalin and [Ala]-methionine enkephalin). The MtC18 sorbents were especially selective against endomorphin 1 and substance P (7-11)). The best results in terms of sensitivity and inter-microcartridge reproducibility were achieved with the microcartridges obtained from a 10-cm open tubular capillary column with a thin monolithic coating with large through-pores (1-5μm). Run-to-run repeatability, microcartridge durability, linearity ranges and LODs were studied by MtC18-SPE-CE-MS. As expected due to their greater selectivity, the best LOD enhancement was obtained for End1 and SP (7-11) (50 times with regard to CE-MS). Finally, the suitability of the methodology for analysing biological fluids was tested with plasma samples spiked with End1 and SP (7-11). Results obtained were promising because both neuropeptides could be detected at 0.05μgmL(-1), which was almost the same concentration level as for the standard solutions (0.01μgmL(-1)).

  14. Development of novel biocompatible hybrid nanocomposites based on polyurethane-silica prepared by sol gel process.

    Science.gov (United States)

    Rashti, Ali; Yahyaei, Hossein; Firoozi, Saman; Ramezani, Sara; Rahiminejad, Ali; Karimi, Roya; Farzaneh, Khadijeh; Mohseni, Mohsen; Ghanbari, Hossein

    2016-12-01

    Due to high biocompatibility, polyurethane has found many applications, particularly in development of biomedical devices. A new nanocomposite based on thermoset polyurethane and silica nanoparticles was synthesized using sol-gel method. Sol-gel process was fulfilled in two acidic and basic conditions by using tetraethylorthosilicate (TEOS) and trimethoxyisocyanatesilane as precursors. The hybrid films characterized for mechanical and surface properties using tensile strength, contact angle, ATR-FTIR and scanning electron microscopy. Biocompatibility and cytotoxicity of the hybrids were assessed using standard MTT, LDH and TUNEL assays. The results revealed that incorporation of silica nanoparticles was significantly improved tensile strength and mechanical properties of the hybrids. Based on the contact angle results, silica nanoparticles increased hydrophilicity of the hybrids. Biocompatibility by using human lung epithelial cell line (MRC-5) demonstrated that the hybrids were significantly less cytotoxic compared to pristine polymer as tested by MTT and LDH assays. TUNEL assay revealed no signs of apoptosis in all tested samples. The results of this study demonstrated that incorporation of silica nanoparticles into polyurethane lead to the enhancement of biocompatibility, indicating that these hybrids could potentially be used in biomedical field in particular as a new coating for medical implants.

  15. Silica xerogel-chitosan nano-hybrids for use as drug eluting bone replacement.

    Science.gov (United States)

    Lee, Eun-Jung; Jun, Shin-Hee; Kim, Hyoun-Ee; Kim, Hae-Won; Koh, Young-Hag; Jang, Jun-Hyeog

    2010-01-01

    Silica xerogel-chitosan hybrids containing vancomycin were fabricated by the sol-gel process at room temperature and their potential as a drug eluting bone replacement was evaluated in terms of their mechanical properties and drug release behaviors. Regardless of the content of chitosan, all of the prepared hybrids had a uniform mesoporous structure, which would allow the effectual loading of vancomycin. As the content of chitosan was increased, the strength, strain to failure, and work of fracture of the hybrids were significantly enhanced, while the elastic modulus was decreased. These changes in the mechanical properties were mainly attributed to the mitigation of the brittleness of the silica xerogel through its hybridization with the flexible chitosan phase. In addition, the initial burst-effect was remarkably reduced by increasing the content of chitosan. The hybrids with more than 30% chitosan could release the vancomycin for an extended period of time in a controlled manner.

  16. Effect of the presence of an ordered micro-pillar array on the formation of silica monoliths.

    Science.gov (United States)

    Detobel, Frederik; Eghbali, Hamed; De Bruyne, Selm; Terryn, Herman; Gardeniers, Han; Desmet, Gert

    2009-10-30

    We report on the synthesis of siloxane-based monoliths in the presence of a two-dimensional, perfectly ordered array of micro-pillars. Both methyltrimethoxysilane- and tetramethoxysilane-based monoliths were considered. The obtained structures were analyzed using scanning-electron microscopy and can be explained from the general theory of surface-directed phase separation in confined spaces. The formed structures are to a large extent nearly exclusively determined by the ratio between the bulk domain size of the monolith on the one hand and the distance between the micro-pillars on the other hand. When this ratio is small, the presence of the pillars has nearly no effect on the morphology of the produced monoliths. However, when the ratio approaches unity and ascends above it, some new types of monolith morphologies are induced, two of which appear to have interesting properties for use as novel chromatographic supports. One of these structures (obtained when the domain size/inter-pillar distance ratio is around unity) is a 3D network of linear interconnections between the pillars, organized such that all skeleton branches are oriented perpendicular to the micro-pillar surface. A second interesting structure is obtained at even higher values of the domain size/inter-pillar distance ratio. In this case, each individual micro-pillar is uniformly coated with a mesoporous shell.

  17. Experimental and numerical validation of the effective medium theory for the B-term band broadening in 1st and 2nd generation monolithic silica columns.

    Science.gov (United States)

    Deridder, Sander; Vanmessen, Alison; Nakanishi, Kazuki; Desmet, Gert; Cabooter, Deirdre

    2014-07-18

    Effective medium theory (EMT) expressions for the B-term band broadening in monolithic silica columns are presented at the whole-column as well as at the mesoporous skeleton level. Given the bi-continuous nature of the monolithic medium, regular as well as inverse formulations of the EMT-expressions have been established. The established expressions were validated by applying them to a set of experimental effective diffusion (Deff)-data obtained via peak parking on a number of 1st and 2nd generation monolithic silica columns, as well as to a set of numerical diffusion simulations in a simplified monolithic column representation (tetrahedral skeleton model) with different external porosities and internal diffusion coefficients. The numerically simulated diffusion data can be very closely represented over a very broad range of zone retention factors (up to k″=80) using the established EMT-expressions, especially when using the inverse variant. The expressions also allow representing the experimentally measured effective diffusion data very closely. The measured Deff/Dmol-values were found to decrease significantly with increasing retention factor, in general going from about Deff/Dmol=0.55 to 0.65 at low k″ (k″≅1.5-3.8) to Deff/Dmol=0.25 at very high k″ (k″≅40-80). These values are significantly larger than observed in fully-porous and core-shell particles. The intra-skeleton diffusion coefficient (Dpz) was typically found to be of the order of Dpz/Dmol=0.4, compared to Dpz/Dmol=0.2-0.35 observed in most particle-based columns. These higher Dpz/Dmol values are the cause of the higher Deff/Dmol values observed. In addition, it also appears that the higher internal diffusion is linked to the higher porosity of the mesoporous skeleton that has a relatively open structure with relatively wide pores. The observed (weak) relation between Dpz/Dmol and the zone retention factor appears to be in good agreement with that predicted when applying the regular

  18. Characterization of a silica-PVA hybrid for high density and stable silver dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Dorin, Bryce, E-mail: bryce.dorin@postgrad.manchester.ac.uk [The Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); School of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Zhu, Guangyu, E-mail: g.zhu@liverpool.ac.uk [Lairdside Laser Engineering Centre, The University of Liverpool, Campbeltown Road, Merseyside, CH41 9HP (United Kingdom); Parkinson, Patrick, E-mail: patrick.parkinson@manchester.ac.uk [The Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Perrie, Walter, E-mail: wpfemto1@liverpool.ac.uk [Lairdside Laser Engineering Centre, The University of Liverpool, Campbeltown Road, Merseyside, CH41 9HP (United Kingdom); Benyezzar, Med, E-mail: med.benyezzar@manchester.ac.uk [The Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Scully, Patricia, E-mail: patricia.scully@manchester.ac.uk [The Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); School of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom)

    2016-07-01

    A silica and polyvinyl alcohol (PVA) hybrid material mixed with a high density of silver ions is synthesised and characterized in this work. The hybrid material can be cast into thick films, which we determined to be homogeneous using Raman spectroscopy. We observed that the silver ions remain stable in the material over time and at temperatures of 100 °C, which represents a marked improvement over previous solid solutions of silver. Differential scanning calorimetry and thermogravimetric analysis indicate the rapid activation of silver at 173 °C, resulting in a dense formation of silver nanoparticles within the hybrid. The activation of silver was also demonstrated in 3-dimensional geometries using femtosecond duration laser pulses. These results illustrate the silica-PVA hybrid is an attractive material for developing silver-insulator composites. - Highlights: • A novel PVA-silica hybrid is developed for silver ion dissolution. • The hybrid exhibits a high silver saturation point and good silver stability. • Heating and laser irradiation are capable of converting the silver ions to metal. • The hybrid material enables the fabrication of 3D metal-insulator composites.

  19. Hybrid cellulase aggregate with a silica core for hydrolysis of cellulose and biomass.

    Science.gov (United States)

    Sutarlie, Laura; Yang, Kun-Lin

    2013-12-01

    Cellulase is an important enzyme for hydrolyzing cellulose to form glucose. To recycle cellulase after the reaction, cellulase is often immobilized on solid supports but its activity is also compromised. In this study, we show a new hybrid cellulase aggregate with a silica core, which is prepared by physical adsorption of cross-linked cellulase on a highly porous solid support silica gel. The hybrid cellulase aggregate exhibits highest activity at pH 4.8 and 51°C, similar to the optimum condition of free cellulase. This hybrid cellulase aggregate can produce 3.4 g/L of glucose within 2 h, which is two times higher than glucose produced by using cross-linked cellulase aggregate alone (without silica core). Another advantage of the hybrid cellulase aggregate is that it can settle down naturally after the hydrolysis of cellulose, thanks to the presence of the silica core. To show its practical applications, we also study the hydrolysis of palm oil fiber by using the hybrid cellulase aggregate. Up to 5.0 g/L of glucose can be produced within 24h, and this process can be repeated five times with only 19% decrease in activity. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Efficiency of a miniaturized silica monolithic cartridge in reducing matrix ions as demonstrated in the simultaneous extraction of morphine and codeine from urine samples for quantification with liquid chromatography-tandem mass spectrometry (LC-MS/MS).

    Science.gov (United States)

    Nema, T; Chan, E C Y; Ho, P C

    2011-09-01

    Presence of matrix ions could negatively affect the sensitivity and selectivity of liquid chromatography-tandem mass spectrometer (LC-MS/MS). In this study, the efficiency of a miniaturized silica monolithic cartridge in reducing matrix ions was demonstrated in the simultaneous extraction of morphine and codeine from urine samples for quantification with LC-MS. The miniaturized silica monolith with hydroxyl groups present on the largely exposed surface area function as a weak cation exchanger for solid phase extraction (SPE). The miniaturized silica cartridge in 1 cm diameter and 0.5 cm length was housed in a 2-ml syringe fixed over a SPE vacuum manifold for extraction. The cleaning effectiveness of the cartridge was confirmed by osmometer, atomic absorption spectrometer, LC-MS and GC-TOFMS. The drugs were efficiently extracted from urine samples with recoveries ranging from 86% to 114%. The extracted analytes, after concentration and reconstitution, were quantified using LC-MS/MS. The limits of detection for morphine and codeine were 2 ng/ml and 1 ng/mL, respectively. The relative standard deviations of measurements ranged from 3% to 12%. The monolithic sorbent offered good linearity with correlation coefficients > 0.99, over a concentration range of 50-500 ng/ml. The silica monolithic cartridge was found to be more robust than the particle-based packed sorbent and also the commercial cartridge with regards to its recyclability and repeated usage with minimal loss in efficiency. Our study demonstrated the efficiency of the miniaturized silica monolith for removal of matrix ions and extraction of drugs of abuse in urinary screening.

  1. Synthesis, characterizations and electro-optical properties of nonlinear optical polyimide/silica hybrid

    Directory of Open Access Journals (Sweden)

    2007-03-01

    Full Text Available Transparent Nonlinear Optical (NLO inorganic/organic (polyimide/silica hybrid composites with covalent links between the inorganic and the organic networks were prepared by the sol-gel method. The silica content in the hybrid films was varied from 0 to 22.5/wt%. The prepared PI hybrids were characterized by IR, UV-Vis, Thermogravimetric analysis (TGA, X-ray diffraction (XRD, Scanning Electron Microscopy (SEM and Transmission Electron Microscopy (TEM. They exhibited fair good optical transparency. The SiO2 phase was well dispersed in the polymer matrix. DSC and TGA results showed that these hybrid materials had excellent thermal stability. The polymer solutions could be spin coated on the indium-tin-oxide (ITO glass to form optical quality thin films. The electro-optic coefficients (γ33 at the wavelength of 832 nm for polymer thin films poled were in the range of 19-27 pm/V.

  2. Hybrid Luminescent Films Obtained by Covalent Anchoring Terbium Complex to Silica-based Network

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    New monomer N-(4-carboxyphenyl)-NL-(propyltriethoxysilyl)urea (1) which acts as both a ligand for Tb3+ ion and a sol-gel precursor has been synthesized and characterized by 1H NMR, and MS. Hybrid luminescent thin films consisting of organoterbium covalently bonded to a silica-based network have been obtained in situ via a sol-gel approach. Strong line emission of Tb3+ ion was observed from the hybrid luminescent films under UV excitation.

  3. Porosity Study of Hybrid Silica Mesostructure in Aluminium Oxide Membrane Columnar by Cyclic Voltammetry Method

    Directory of Open Access Journals (Sweden)

    M.N. Jalil

    2011-12-01

    Full Text Available Silica mesostructure has been grown within with a porous aluminium oxide membrane columnar material (hybrid-AOM. This was prepared using a sol-gel technique with Pluronic P123 triblock copolymer as the structure-directing agent and tetraethyl orthosilicate as the inorganic source. The porosity of the hybrid-AOM after ethanol extraction was calculated from the cyclic voltammetry response of a neutral probe (FcMeOH, using Randles-Sevčik equation.

  4. Quantum efficiency of colloidal suspensions containing quantum dot/silica hybrid particles

    Science.gov (United States)

    Jeon, Hyungjoon; Yoon, Cheolsang; Lee, Sooho; Lee, Doh C.; Shin, Kyusoon; Lee, Kangtaek

    2016-10-01

    We have investigated the fluorescence properties of colloidal suspensions conntaining quantum dot (QD)/silica hybrid particles. First, we synthesized QD/silica hybrid particles with silica-QD-silica (SQS) core-shell-shell geometry, and monitored the quantum efficiencies of their suspensions at various particle concentrations. We found that the quantum efficiency (QE) of SQS particles in deionized (DI) water was much lower than that of the QDs even at low particle concentration, mainly due to the light scattering of emitted photons at the silica/water interface, followed by reabsorption by QDs. As the concentration of SQS particles was increased, both light scattering and reabsorption by QDs became more important, which further reduced the QE. Refractive index-matched solvent, however, reduced light scattering, yielding greater QE than DI water. Next, we induced aggregation of SQS particles, and found that QE increased as particles aggregated in DI water because of reduced light scattering and reabsorption, whereas it remained almost constant in the refractive index-matched solvent. Finally, we studied aggregation of highly concentrated silica particle suspensions containing a low concentration of SQS particles, and found that QE increased with aggregation because light scattering and reabsorption were reduced.

  5. synthesis of organoamine-silica hybrids using cashew nut shell ...

    African Journals Online (AJOL)

    Mgina

    at different ratios using cashew nut shell liquid (CNSL) components as templates. ... indeed the organoamine groups were attached onto the silica surface, with a maximum .... observation is attributed to steric effects. .... groups reduces the surface areas and pore volume of the materials (Krishna et al. ... diffusion limitations.

  6. Extraction of amphetamines and methylenedioxyamphetamines from urine using a monolithic silica disk-packed spin column and high-performance liquid chromatography-diode array detection.

    Science.gov (United States)

    Namera, Akira; Nakamoto, Akihiro; Nishida, Manami; Saito, Takeshi; Kishiyama, Izumi; Miyazaki, Shota; Yahata, Midori; Yashiki, Mikio; Nagao, Masataka

    2008-10-24

    To overcome the limitations of solid-phase extraction, we developed a device comprising a spin column packed with octadecyl silane-bonded monolithic silica for extracting amphetamines and methylenedioxyamphetamines from urine. Urine (0.5mL), buffer (0.4mL), and methoxyphenamine (internal standard) were directly put into the preactivated column. The column was centrifuged (3000rpm, 5min) for sample loading and washed. The adsorbed analytes were eluted and analyzed by high-performance liquid chromatography, without evaporation. The results were as follows: linear curves (drug concentrations of 0.2-20microg/mL); correlation coefficients >0.99; detection limit, 0.1microg/mL. The proposed method is not only useful for drugs from biological materials but also highly reproducible for the analysis of these drugs in urine.

  7. Development of a silica monolith modified with Fe3O4 nano-particles in centrifugal spin column format for the extraction of phosphorylated compounds.

    Science.gov (United States)

    Alwy, Ali; Clarke, Sarah P; Brougham, Dermot F; Twamley, Brendan; Paull, Brett; White, Blánaid; Connolly, Damian

    2015-01-01

    In this study, citrate-stabilised iron oxide nano-particles (∼16 nm) have been immobilised on commercial silica monolithic centrifugal spin columns (MonoSpin) for the extraction of phosphorylated compounds. Two alternative strategies were adopted involving either direct electrostatic attachment to an aminated MonoSpin (single-layer method) in the first instance, or the use of a layer-by-layer method with poly(diallyldimethylammonium) chloride. Field-emission scanning electron spectroscopy and energy-dispersive X-ray spectroscopy was used for confirming notably higher coverage of nano-particles using the layer-by-layer method (2.49 ± 0.53 wt%) compared with the single-layer method (0.43 ± 0.30 wt%). The modified monolith was used for the selective separation/extraction of adenosine monophosphate, adenosine diphosphate and adenosine triphosphate with elution using a phosphate buffer. A reversed-phase liquid chromatographic assay was used for confirming that adenosine, as a non-phosphorylated control was not retained on the modified MonoSpin devices, whereas recovery of 80% for adenosine monophosphate, 86% for adenosine diphosphate and 82% for adenosine triphosphate was achieved.

  8. Porous polylactic acid-silica hybrids: preparation, characterization, and study of mesenchymal stem cell osteogenic differentiation.

    Science.gov (United States)

    Pandis, Christos; Trujillo, Sara; Matos, Joana; Madeira, Sara; Ródenas-Rochina, Joaquín; Kripotou, Sotiria; Kyritsis, Apostolos; Mano, João F; Gómez Ribelles, José Luis

    2015-02-01

    A novel approach to reinforce polymer porous membranes is presented. In the prepared hybrid materials, the inorganic phase of silica is synthesized in-situ and inside the pores of aminolyzed polylactic acid (PLA) membranes by sol-gel reactions using tetraethylorthosilicate (TEOS) and glycidoxypropyltrimethoxysilane (GPTMS) as precursors. The hybrid materials present a porous structure with a silica layer covering the walls of the pores while GPTMS serves also as coupling agent between the organic and inorganic phase. The adjustment of silica precursors ratio allows the modulation of the thermomechanical properties. Culture of mesenchymal stem cells on these supports in osteogenic medium shows the expression of characteristic osteoblastic markers and the mineralization of the extracellular matrix.

  9. Synthesis and Charaterization of Silica-Based Aldehyde Chitosan Hybrid Material for Biodiesel Purification.

    Science.gov (United States)

    da Silva, Sandra Rodrigues; de Albuquerque, Nilson J A; de Almeida, Rusiene M; de Abreu, Fabiane C

    2017-09-25

    This study concerns the development and charaterization of Silica-based aldehyde Chitosan hybrid material as an adsorbent for biodiesel purification. This biocomposite was prepared by sol-gel route and oxidation with periodate, and then characterized. FTIR experiments showed that the hybrid formed presents absorption bands similar to those of Chitosan-Silica, with the exception of the vibrations at 1480 cm(-1) and 1570 cm(-1) attributed to the symmetrical angular deformation in the N-H plane, and possess large N₂ Brunauer-Emmett-Teller (BET) surface areas. Thermogravimetric analysis (TG) and scanning electron microscopy (SEM) was also carried out. Adsorption studies of bioadsorbents involving the analysis of free glycerol, soap, acidity, diglycerides, triglycerides, and fluorescence spectroscopy showed that silica-based aldehyde chitosan has a good affinity for glycerol and a good purification process.

  10. Synthesis and Charaterization of Silica-Based Aldehyde Chitosan Hybrid Material for Biodiesel Purification

    Directory of Open Access Journals (Sweden)

    Sandra Rodrigues da Silva

    2017-09-01

    Full Text Available This study concerns the development and charaterization of Silica-based aldehyde Chitosan hybrid material as an adsorbent for biodiesel purification. This biocomposite was prepared by sol-gel route and oxidation with periodate, and then characterized. FTIR experiments showed that the hybrid formed presents absorption bands similar to those of Chitosan-Silica, with the exception of the vibrations at 1480 cm−1 and 1570 cm−1 attributed to the symmetrical angular deformation in the N-H plane, and possess large N2 Brunauer–Emmett–Teller (BET surface areas. Thermogravimetric analysis (TG and scanning electron microscopy (SEM was also carried out. Adsorption studies of bioadsorbents involving the analysis of free glycerol, soap, acidity, diglycerides, triglycerides, and fluorescence spectroscopy showed that silica-based aldehyde chitosan has a good affinity for glycerol and a good purification process.

  11. Monolithic silica spin column extraction and simultaneous derivatization of amphetamines and 3,4-methylenedioxyamphetamines in human urine for gas chromatographic-mass spectrometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Nakamoto, Akihiro [Scientific Investigation Laboratory, Hiroshima Prefectural Police Headquarters, Kohnan 2-26-3, Naka-ku, Hiroshima 730-0825 (Japan); Nishida, Manami [Hiroshima University Technical Center, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551 (Japan); Saito, Takeshi [Department of Emergency and Critical Care Medicine, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1143 (Japan); Kishiyama, Izumi; Miyazaki, Shota [GL Sciences Inc., Sayamagahara 237-2, Iruma, Saitama 358-0032 (Japan); Murakami, Katsunori [Scientific Investigation Laboratory, Hiroshima Prefectural Police Headquarters, Kohnan 2-26-3, Naka-ku, Hiroshima 730-0825 (Japan); Nagao, Masataka [Department of Forensic Medicine, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551 (Japan); Namura, Akira, E-mail: namera@hiroshima-u.ac.jp [Department of Forensic Medicine, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551 (Japan)

    2010-02-19

    A simple, sensitive, and specific method with gas chromatography-mass spectrometry was developed for simultaneous extraction and derivatization of amphetamines (APs) and 3,4-methylenedioxyamphetamines (MDAs) in human urine by using a monolithic silica spin column. All the procedures, such as sample loading, washing, and elution were performed by centrifugation. APs and MDAs in urine were adsorbed on the monolithic silica and derivatized with propyl chloroformate in the column. Methamphetamine-d{sub 5} was used as an internal standard. The linear ranges were 0.01-5.0 {mu}g mL{sup -1} for methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA) and 0.02-5.0 {mu}g mL{sup -1} for amphetamine (AP) and 3,4-methylenedioxyamphetamine (MDA) (coefficient of correlation {>=}0.995). The recovery of APs and MDAs in urine was 84-94%, and the relative standard deviation of the intra- and interday reproducibility for urine samples containing 0.1, 1.0, and 4.0 {mu}g mL{sup -1} of APs and MDAs ranged from 1.4% to 13.6%. The lowest detection limit (signal-to-noise ratio {>=} 3) in urine was 5 ng mL{sup -1} for MA and MDMA and 10 ng mL{sup -1} for AP and MDA. The proposed method can be used to perform simultaneous extraction and derivatization on spin columns that have been loaded with a small quantity of solvent by using centrifugation.

  12. Design of a superhydrophobic and superoleophilic film using cured fluoropolymer@silica hybrid

    Science.gov (United States)

    Yang, Hao; Pi, Pihui; Yang, Zhuo-ru; Lu, Zhong; Chen, Rong

    2016-12-01

    Recently, considerable efforts have been made on superhydrophobic-superoleophilic filter to satisfy the requirements of the applications to oil/water separation. In this work, we obtained a superhydrophobic and superoleophilic film by coating cured fluoropolymer@silica hybrid on stainless steel mesh. Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric-differential scanning calorimetry (TG-DSC) were used to determine the chemical composition and thermal stability of the sample. The effect of silica nanoparticles (NPs) concentration on the surface property of the hybrid film was analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle analyzer. The results indicate that silica NPs not only enhance the thermal stability, but also strengthen the hydrophobicity and oleophilicity of the film. When 20 wt% silica NPs was added into the thermosetting fluoropolymer, the hybrid film shows both superhydrophobicity and superoleophilicity owing to the large surface roughness factor (RMS) and porous structure. Moreover, the hybrid film could be used to separate water from different oils effectively. When the pore size of the mesh is less than 300 μm, the oil/water separation efficiency of the film reaches above 99%, which shows a great potential application to dehydrate fuel oils.

  13. Stable Hybrid Silica Nanosieve Membranes for the Dehydration of Lower Alcohols

    NARCIS (Netherlands)

    Kreiter, Robert; Rietkerk, Mariëlle D.A.; Castricum, Hessel L; Veen, van Henk M.; Elshof, ten Johan E.; Vente, Jaap F.

    2009-01-01

    A thirst for water: Organic–inorganic hybrid silica nanosieve membranes with narrow pore size distributions were developed for the separation of binary (bio)alcohol/water mixtures, for example, to remove water from wet biofuels during production. These membranes dehydrate lower alcohols and show a s

  14. Magnetic silica hybrids modified with guanidine containing co-polymers for drug delivery applications

    Energy Technology Data Exchange (ETDEWEB)

    Timin, Alexander S., E-mail: a_timin@mail.ru [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000 Ivanovo (Russian Federation); RASA Center in Tomsk, Tomsk Polytechnic University, 30, Lenin Avenue, 634500 Tomsk (Russian Federation); Khashirova, Svetlana Yu. [Kabardino-Balkar State University, ul. Chernyshevskogo 173, Nal' chik, 360004 Kabardino-Balkaria (Russian Federation); Rumyantsev, Evgeniy V.; Goncharenko, Alexander A. [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000 Ivanovo (Russian Federation)

    2016-07-01

    Guanidine containing co-polymers grafted onto silica nanoparticles to form core-shell structure were prepared by sol-gel method in the presence of γ-Fe{sub 2}O{sub 3} nanoparticles. The morphological features for uncoated and coated silica particles have been characterized with scanning electron microscopy. The results show that the polymer coated silicas exhibit spherical morphology with rough polymeric surface covered by γ-Fe{sub 2}O{sub 3} nanoparticles. The grafting amount of guanidine containing co-polymers evaluated by thermogravimetric analysis was in the range from 17 to 30%. Then, the drug loading properties and cumulative release of silica hybrids modified with guanidine containing co-polymers were evaluated using molsidomine as a model drug. It was shown that after polymer grafting the loading content of molsidomine could reach up to 3.42 ± 0.21 and 2.34 ± 0.14 mg/g respectively. The maximum drug release of molsidomine is achieved at pH 1.6 (approximately 71–75% release at 37 °C), whereas at pH 7.4 drug release is lower (50.4–59.6% release at 37 °C). These results have an important implication that our magneto-controlled silica hybrids modified with guanidine containing co-polymers are promising as drug carriers with controlled behaviour under influence of magnetic field. - Highlights: • Polymer coated silica hybrids containing γ-Fe{sub 2}O{sub 3} were prepared via sol–gel method. • Polymer grafting influences pH-response and surface properties of final products. • Molsidomine as a model drug was effectively loaded into polymer coated silicas. • The drug loading depends on the nature of grafted polymer and its content.

  15. Synthesis and characterization of hybrid silica/PMMA nanoparticles and their use as filler in dental composites

    Energy Technology Data Exchange (ETDEWEB)

    Canché-Escamilla, G., E-mail: gcanche@cicy.mx [Unidad de Materiales, Centro de Investigación Científica de Yucatán A.C. Calle 43 No. 130 Col. Chuburná de Hidalgo, Mérida, Yucatán 97200 (Mexico); Duarte-Aranda, S. [Unidad de Materiales, Centro de Investigación Científica de Yucatán A.C. Calle 43 No. 130 Col. Chuburná de Hidalgo, Mérida, Yucatán 97200 (Mexico); Toledano, M. [Facultad de Odontología, Universidad de Granada, Campus Universitario de Cartuja s/n, Granada 18071 (Spain)

    2014-09-01

    The effect of hybrid silica/poly(methylmethacrylate) (PMMA) nanoparticles on the properties of composites for dental restoration was evaluated. Hybrid nanoparticles with silica as core and PMMA as shell were obtained by a seeded emulsion polymerization process. Fourier transform infrared spectrum of the hybrid nanoparticles shows an intense peak at 1730 cm{sup −1}, corresponding to carbonyl groups (C=O) of the ester. The thermal stability of the hybrid particles decreases with increasing amounts of PMMA and the residual mass at 700 °C corresponds to the silica content in the hybrid particles. Composites were obtained by dispersing nanoparticles (silica or hybrid), as fillers, in a resin—bis glycidyl dimethacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) (40%/60% (w/w)). The paste was then placed in a mold and polymerized under light irradiation. During the preparation of the composites, with the hybrid nanoparticles, the monomers swell the PMMA shell and after photo-curing, a semi-interpenetrating network (semi-IPN) is obtained around the silica core. The properties of the composites, obtained using the hybrid nanoparticles, depend on the filler content and the amount of PMMA in the semi-IPN matrix. For composites with similar inorganic filler contents, the composites with low amounts of PMMA shell had higher modulus than those in which silica was used as the filler. - Highlights: • Hybrid nanoparticles silica/PMMA were used as fillers in dental composites. • The properties of the hybrid nanoparticle depend on the silica/PMMA content ratio. • A higher content of inorganic filler was obtained using hybrid nanoparticle. • Composites with higher modulus were obtained using hybrid nanoparticles. • A semi-IPN matrix between the PMMA shell and the resin is obtained.

  16. Comprehensive profiling of ribonucleosides modification by affinity zirconium oxide-silica composite monolithic column online solid-phase microextraction - Mass spectrometry analysis.

    Science.gov (United States)

    Jiang, Han-Peng; Chu, Jie-Mei; Lan, Meng-Dan; Liu, Ping; Yang, Na; Zheng, Fang; Yuan, Bi-Feng; Feng, Yu-Qi

    2016-09-02

    More than 140 modified ribonucleosides have been identified in RNA. Determination of endogenous modified ribonucleosides in biological fluids may serve as non-invasive disease diagnostic strategy. However, detection of the modified ribonucleosides in biological fluids is challenging, especially for the low abundant modified ribonucleosides due to the serious matrix interferences of biological fluids. Here, we developed a facile preparation strategy and successfully synthesized zirconium oxide-silica (ZrO2/SiO2) composite capillary monolithic column that exhibited excellent performance for the selective enrichment of cis-diol-containing compounds. Compared with the boronate-based affinity monolith, the ZrO2/SiO2 monolith showed ∼2 orders of magnitude higher extraction capacity and can be used under physiological pH (pH 6.5-7.5). Using the prepared ZrO2/SiO2 composite monolith as the trapping column and reversed-phase C18 column as the analytical column, we further established an online solid-phase microextraction (SPME) in combination with liquid chromatography-mass spectrometry (online SPME-LC-MS/MS) analysis for the comprehensive profiling of ribonucleosides modification in human urine. Our results showed that 68 cis-diol-containing ribosylated compounds were identified in human urine, which is, to the best of our knowledge, the highest numbers of cis-diol-containing compounds were determined in a single analysis. It is worth noting that four modified ribonucleosides were discovered in the human urine for the first time. In addition, the quantification results from the pooled urine samples showed that compared to healthy controls, the contents of sixteen ribose conjugates in the urine of gastric cancer, eleven in esophagus cancer and seven in lymphoma increased more than two folds. Among these ribose conjugates, four ribose conjugates increased more than two folds in both gastric cancer and esophagus cancer; three ribose conjugates increased more than two

  17. Study on Polyimide/Silica Hybrid Films via Directly Intermingle Method

    Institute of Scientific and Technical Information of China (English)

    Bin ZHAO; Bao-Lin RAO

    2005-01-01

    @@ 1Introduction In recent years, polyimide hybrid materials have received considerable attention due to the dramatic improvements over their pristine state in thermal stabilities, mechanical properties and other special features by introducing only small fraction inorganic additives[1]. Polyimide/silica hybrid materials were studied mostly by sol-gel route[2]. However the storage stability of the sol resin is a practical problem and has not researched on it so far. On the other hand, nano-sized silica has been produced on a large scale and industrialized. In this paper, polyimide/siliea hybrid films were prepared via directly intermingle method. The storage stability of the sol resin, the thermal and mechanical properties of the resulting films were investigated.

  18. Evolution of microstructure in mixed niobia-hybrid silica thin films from sol-gel precursors.

    Science.gov (United States)

    Besselink, Rogier; Stawski, Tomasz M; Castricum, Hessel L; ten Elshof, Johan E

    2013-08-15

    The evolution of structure in sol-gel derived mixed bridged silsesquioxane-niobium alkoxide sols and drying thin films was monitored in situ by small-angle X-ray scattering. Since sol-gel condensation of metal alkoxides proceeds much faster than that of silicon alkoxides, the incorporation of d-block metal dopants into silica typically leads to formation of densely packed nano-sized metal oxide clusters that we refer as metal oxide building blocks in a silica-based matrix. SAXS was used to study the process of niobia building block formation while drying the sol as a thin film at 40-80°C. The SAXS curves of mixed niobia-hybrid silica sols were dominated by the electron density contrast between sol particles and surrounding solvent. As the solvent evaporated and the sol particles approached each other, a correlation peak emerged. Since TEM microscopy revealed the absence of mesopores, the correlation peak was caused by a heterogeneous system of electron-rich regions and electron poor regions. The regions were assigned to small clusters that are rich in niobium and which are dispersed in a matrix that mainly consisted of hybrid silica. The correlation peak was associated with the typical distances between the electron dense clusters and corresponded with distances in real space of 1-3 nm. A relationship between the prehydrolysis time of the silica precursor and the size of the niobia building blocks was observed. When 1,2-bis(triethoxysilyl)ethane was first hydrolyzed for 30 min before adding niobium penta-ethoxide, the niobia building blocks reached a radius of 0.4 nm. Simultaneous hydrolysis of the two precursors resulted in somewhat larger average building block radii of 0.5-0.6 nm. This study shows that acid-catalyzed sol-gel polymerization of mixed hybrid silica niobium alkoxides can be rationalized and optimized by monitoring the structural evolution using time-resolved SAXS.

  19. Synthesis and characterization of hybrid silica/PMMA nanoparticles and their use as filler in dental composites.

    Science.gov (United States)

    Canché-Escamilla, G; Duarte-Aranda, S; Toledano, M

    2014-09-01

    The effect of hybrid silica/poly(methylmethacrylate) (PMMA) nanoparticles on the properties of composites for dental restoration was evaluated. Hybrid nanoparticles with silica as core and PMMA as shell were obtained by a seeded emulsion polymerization process. Fourier transform infrared spectrum of the hybrid nanoparticles shows an intense peak at 1,730 cm(-1), corresponding to carbonyl groups (CO) of the ester. The thermal stability of the hybrid particles decreases with increasing amounts of PMMA and the residual mass at 700°C corresponds to the silica content in the hybrid particles. Composites were obtained by dispersing nanoparticles (silica or hybrid), as fillers, in a resin-bis glycidyl dimethacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) (40%/60% (w/w)). The paste was then placed in a mold and polymerized under light irradiation. During the preparation of the composites, with the hybrid nanoparticles, the monomers swell the PMMA shell and after photo-curing, a semi-interpenetrating network (semi-IPN) is obtained around the silica core. The properties of the composites, obtained using the hybrid nanoparticles, depend on the filler content and the amount of PMMA in the semi-IPN matrix. For composites with similar inorganic filler contents, the composites with low amounts of PMMA shell had higher modulus than those in which silica was used as the filler. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Aminopropyl-Silica Hybrid Particles as Supports for Humic Acids Immobilization

    Directory of Open Access Journals (Sweden)

    Mónika Sándor

    2016-01-01

    Full Text Available A series of aminopropyl-functionalized silica nanoparticles were prepared through a basic two step sol-gel process in water. Prior to being aminopropyl-functionalized, silica particles with an average diameter of 549 nm were prepared from tetraethyl orthosilicate (TEOS, using a Stöber method. In a second step, aminopropyl-silica particles were prepared by silanization with 3-aminopropyltriethoxysilane (APTES, added drop by drop to the sol-gel mixture. The synthesized amino-functionalized silica particles are intended to be used as supports for immobilization of humic acids (HA, through electrostatic bonds. Furthermore, by inserting beside APTES, unhydrolysable mono-, di- or trifunctional alkylsilanes (methyltriethoxy silane (MeTES, trimethylethoxysilane (Me3ES, diethoxydimethylsilane (Me2DES and 1,2-bis(triethoxysilylethane (BETES onto silica particles surface, the spacing of the free amino groups was intended in order to facilitate their interaction with HA large molecules. Two sorts of HA were used for evaluating the immobilization capacity of the novel aminosilane supports. The results proved the efficient functionalization of silica nanoparticles with amino groups and showed that the immobilization of the two tested types of humic acid substances was well achieved for all the TEOS/APTES = 20/1 (molar ratio silica hybrids having or not having the amino functions spaced by alkyl groups. It was shown that the density of aminopropyl functions is low enough at this low APTES fraction and do not require a further spacing by alkyl groups. Moreover, all the hybrids having negative zeta potential values exhibited low interaction with HA molecules.

  1. Gravimetric chemical sensors based on silica-based mesoporous organic-inorganic hybrids.

    Science.gov (United States)

    Xu, Jiaqiang; Zheng, Qi; Zhu, Yongheng; Lou, Huihui; Xiang, Qun; Cheng, Zhixuan

    2014-09-01

    Silica-based mesoporous organic-inorganic hybrid material modified quartz crystal microbalance (QCM) sensors have been examined for their ability to achieve highly sensitive and selective detection. Mesoporous silica SBA-15 serves as an inorganic host with large specific surface area, facilitating gas adsorption, and thus leads to highly sensitive response; while the presence of organic functional groups contributes to the greatly improved specific sensing property. In this work, we summarize our efforts in the rational design and synthesis of novel sensing materials for the detection of hazardous substances, including simulant nerve agent, organic vapor, and heavy metal ion, and develop high-performance QCM-based chemical sensors.

  2. Silica-graphene oxide hybrid composite particles and their electroresponsive characteristics.

    Science.gov (United States)

    Zhang, Wen Ling; Choi, Hyoung Jin

    2012-05-01

    Silica-graphene oxide (Si-GO) hybrid composite particles were prepared by the hydrolysis of tetraethyl orthosilicate (TEOS) in the presence of hydrophilic GO obtained from a modified Hummers method. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images provided visible evidence of the silica nanoparticles grafted on the surface of GO, resulting in Si-GO hybrid composite particles. Energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) spectra indicated the coexistence of silica and GO in the composite particles. The Si-GO hybrid composite particles showed better thermal stability than that of GO according to thermogravimetric analysis (TGA). The electrorheological (ER) characteristics of the Si-GO hybrid composite based ER fluid were examined further by optical microscopy and a rotational rheometer in controlled shear rate mode under various electric field strengths. Shear stress curves were fitted using both conventional Bingham model and a constitutive Cho-Choi-Jhon model. The polarizability and relaxation time of the ER fluid from dielectric spectra measured using an LCR meter showed a good correlation with its ER characteristics.

  3. Microgel Modified UV-Cured Methacrylic-Silica Hybrid: Synthesis and Characterization

    Directory of Open Access Journals (Sweden)

    Mariaenrica Frigione

    2013-09-01

    Full Text Available An innovative photopolymerizable microgel modified UV-cured acrylic-silica hybrid formulation was developed and characterized for possible use as protective coating for different substrates. A deep investigation, aiming at providing a strong scientific basis for the production of organic-inorganic (O-I hybrids exhibiting phase co-continuity, was firstly carried out. The O-I hybrid first proposed in this study was obtained from organic precursors with a high siloxane content, which are mixed with tetraethoxysilane (TEOS in such a way to produce co-continuous silica nanodomains dispersed within the crosslinked organic phase, as a result of the sol-gel process. The first part of the research deals with the selection and optimization of suitable systems through appropriate chemical modifications, in order to ensure that curing reactions can be carried out at room temperature and in the presence of UV radiation. Firstly, the silica domains are formed, followed by crosslinking reactions of the acrylic groups in the oligomer via a free radical polymerization. The crosslinking reaction was controlled with the use of a suitable photoinitiator. Most of the experimental work was devoted to understanding the morphology of the hybrid system, both in uncured and cured states, and to assess its final thermal and optical properties, using different experiential techniques.

  4. Hybrid organic – silica nanomaterials based on novel A{sub 3}B mixed substituted porphyrin

    Energy Technology Data Exchange (ETDEWEB)

    Fagadar-Cosma, Eugenia [Institute of Chemistry -Timisoara of Romanian Academy, M. Viteazul Ave, No. 24, 300223 Timisoara (Romania); Dudás, Zoltán, E-mail: dudas.zoltan@wigner.mta.hu [Institute of Chemistry -Timisoara of Romanian Academy, M. Viteazul Ave, No. 24, 300223 Timisoara (Romania); MTA Wigner Research Center for Physics, Konkoly Thege Miklós Street, No. 29-33, 1121 Budapest (Hungary); Birdeanu, Mihaela [Institute of Chemistry -Timisoara of Romanian Academy, M. Viteazul Ave, No. 24, 300223 Timisoara (Romania); National Institute for Research and Development in Electrochemistry and Condensed Matter, 1 Plautius Andronescu Street, 300224 Timisoara (Romania); Almásy, László [MTA Wigner Research Center for Physics, Konkoly Thege Miklós Street, No. 29-33, 1121 Budapest (Hungary)

    2014-11-14

    A new A{sub 3}B porphyrin structure, namely: 5-(4-phenoxyphenyl)-10,15,20-tris(4-pyridyl)-porphyrin was synthetized and characterized by FT-IR, UV–vis, Fluorescence, MS, {sup 1}H NMR, TLC and HPLC. Novel hybrid-silica porphyrin nanomaterials were obtained by immobilizing the porphyrin in silica supports synthesized from tetraethoxysilane, tetramethoxysilane or mixtures of tetraethoxysilane/methyltriethoxysilane. Since the behavior and performance of immobilized porphyrin molecules in the silica matrices strongly depend on the structure of the porous network, a comparative characterization of the silica support and the hybrid porphyrin-silica materials was carried out using specific physicochemical characterization methods: UV–vis, Fluorencence, FT-IR spectroscopy, thermal analysis, AFM, nitrogen adsorption and small-angle neutron scattering. The UV–vis spectra show that no protonation and aggregation of porphyrin takes place in the gels made from methyltriethoxysilane precursor. Most of the emission spectra preserve both the shape and the intensity of the corresponding free porphyrin. Due to the lack of aggregation, when using the methyltriethoxysilane precursor, the quenching of fluorescence is also diminished. No matter of the preparation method the specific surface areas increase in the following order: TEOS < TMOS < TEOS/MTES 3:1 < TEOS/MTES 2:1 < TEOS/MTES 1:1. Due to their optical properties, both the novel porphyrin and its derived hybrid materials, especially those synthesized in situ with mixtures of silica precursors TEOS/MTES will be sent for further medical trials in PDT, having characteristics of second generation photosensitizers. Due to large specific surface areas, the same materials will be used as sensitive materials in microsensors for air quality control, to detect the presence of CO, NO{sub x}, excess of CO{sub 2} and low level of O{sub 2}. - Highlights: • Synthesis of new A{sub 3}B type porphyrin exhibiting high fluorescence

  5. Charge collection enhancement by incorporation of gold-silica core-shell nanoparticles into P3HT : PCBM/ZnO nanorod array hybrid solar cells

    NARCIS (Netherlands)

    Wang, Ting-Chung; Su, Yen-Hsun; Hung, Yun-Kai; Yeh, Chen-Sheng; Huang, Li-Wen; Gomulya, Widianta; Lai, Lai-Hung; Loi, Maria A.; Yang, Jih-Sheng; Wu, Jih-Jen

    2015-01-01

    In this work, gold-silica core-shell (Au@silica) nanoparticles (NPs) with various silica-shell thicknesses are incorporated into P3HT:PCBM/ZnO nanorod (NR) hybrid solar cells. Enhancement in the short-circuit current density and the efficiency of the hybrid solar cells is attained with the appropria

  6. Large-scale fabrication of free-standing, micropatterned silica nanotubes via a hybrid hydrogel-templated route.

    Science.gov (United States)

    Chen, Song; Shi, Xuetao; Chinnathambi, Shanmugavel; Hanagata, Nobutaka

    2013-08-01

    Free-standing, micropatterned silica nanotube membranes are in situ fabricated using a micropatterned silica-coated collagen hybrid hydrogel as template. They are substrate-free, and not only maintained their micropatterned microstructure well, but also exhibited strong cell contact guidance ability to direct cell alignment and differentiation, indicating their good potential for biomedical applications.

  7. Experiments on Hybrid Precast Concrete Shear Walls Emulating Monolithic Construction with Different Amounts of Posttensioned Strands and Different Debond Lengths of Grouted Reinforcements

    Directory of Open Access Journals (Sweden)

    Zhangfeng Zhu

    2016-01-01

    Full Text Available This paper proposed a hybrid precast concrete shear wall emulating monolithic construction (HPWEM that utilized grouted vertical connecting reinforcements and unbonded posttensioned high-strength strands across the horizontal joint for the lateral resistance. The grouted reinforcements with predetermined debond length were used to provide strength by tension and energy dissipation by yielding. The posttensioned strands were mainly employed to offer the restoring force to reduce the residual displacement by elastic extension. The overlapping welded closed stirrups improved the confinement property of the restrained concrete, avoiding the brittle failure. Six HPWEM specimens, considering variables including the amounts of strands and the debond lengths of grouted reinforcements, as well as one referenced cast-in-place monolithic wall specimen, were tested under the low-cycle reversed lateral load. The HPWEM specimens were capable of providing strength, stiffness, ductility, and energy dissipation equivalent to that of the monolithic wall specimen under certain variable condition.

  8. UV-cured methacrylic-silica hybrids: Effect of oxygen inhibition on photo-curing kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Corcione, C. Esposito; Striani, R.; Frigione, M., E-mail: mariaenrica.frigione@unisalento.it

    2014-01-20

    Highlights: • The kinetic behavior of novel photopolymerizable organic–inorganic hybrid system was studied as a function of the composition and of the atmosphere for reactions. • The UV-curing reaction of the hybrid mixture was found fast and complete. • The combined presence of thiol monomer and nanostructured silica allows to reduce the effect of inhibition of oxygen towards the radical photopolymerization. - Abstract: The kinetic behavior of innovative photopolymerizable UV-cured methacrylic–silica hybrid formulations, previously developed, was studied and compared to that of a reference control system. The organic–inorganic (O–I) hybrids proposed in this study are obtained from organic precursors with a high siloxane content mixed with tetraethoxysilane (TEOS) in such a way to produce co-continuous silica nano-domains dispersed within a cross-linked organic phase, as a result of the hydrolysis and condensation reactions. The kinetics of the radical photopolymerization mechanism induced by UV-radiations, in presence of a suitable photoinitiator, was studied by calorimetric, FTIR and Raman spectroscopic analyses, by varying the composition of the mixtures and the atmosphere for reactions. The well known effect of oxygen on the kinetic mechanism of the free radical photopolymerization of the methacrylic–siloxane based monomers was found to be strongly reduced in the hybrid system, especially when a proper thiol was used. The experimental calorimetric data were fitted using a simple kinetic model for radical photopolymerization reactions, obtaining a good agreement between the experimental data and the theoretical model. From the comparison of the kinetic constants calculated for control and hybrid systems, it was possible to assess the effect of the composition, as well as of the atmosphere used during the photo-polymerization process, on the kinetic of photopolymerization reaction.

  9. Hybrid-integrated coherent receiver using silica-based planar lightwave circuit technology

    Science.gov (United States)

    Kim, Jong-Hoi; Choe, Joong-Seon; Choi, Kwang-Seong; Youn, Chun-Ju; Kim, Duk-Jun; Jang, Sun-Hyok; Kwon, Yong-Hwan; Nam, Eun-Soo

    2011-12-01

    A hybrid-integrated coherent receiver module has been achieved using flip-chip bonding technology, consisting of a silica-based 90°-hybrid planar lightwave circuit (PLC) platform, a spot-size converter integrated waveguide photodiode (SSC-WG-PD), and a dual-channel transimpedance amplifier (TIA). The receiver module shows error-free operation up to 40Gb/s and OSNR sensitivity of 11.5 dB for BER = 10-3 at 25 Gb/s.

  10. Morphologies and Superhydrophobicity of Hybrid Film Surfaces Based on Silica and Fluoropolymer

    Institute of Scientific and Technical Information of China (English)

    Ailan QU; Xiufang WEN; Pihui PI; Jiang CHENG; Zhuoru YANG

    2008-01-01

    Fluoropolymer and different kinds of silica particles were used for controlling surface chemistry and morphology,respectively. A superhydrophobic surface originated from strawberry-like or quincunx-shaped composite silica particles was obtained. The dual size particles are obtained by utilizing the graft of different modified silica particles with epoxy functional group and amine functional group. This makes the surface of film form a composite interface to have irregular binary structure which plays an essential role in trapping air between the substrate surface and the liquid droplets to be necessary for high contact angle and low contact anglehysteresis. The maximum contact angle for water on the hybrid film is about 174±2° and the contact angle hysteresis is less than 2°. The surface morphologies, roughness and the wettability on the surface of films containing different structural silica particles were compared. It was shown that the hierarchical irregularly structure with a low roughness factor and high air-trapped ratio is indispensable for superhydrophobic surface.Although this structural surfaces based on composite silica particles play a vital role in governing the surface wettability, it is necessary to combine with a low surface energy to make the surface superhydrophobic.

  11. Monolithic Hybrid and Passive Mode-Locked 40GHz Quantum Dot Laser Diodes

    DEFF Research Database (Denmark)

    Thompson, M. G.; Larsson, David; Rae, A. R.

    2006-01-01

    For the first time hybrid and passive mode-locking jitter performance is investigated in 40GHz quantum-dot mode-locked lasers. Record low passive mode-locking jitter of 219fs is presented, along with promising hybrid mode-locking results of 124fs.......For the first time hybrid and passive mode-locking jitter performance is investigated in 40GHz quantum-dot mode-locked lasers. Record low passive mode-locking jitter of 219fs is presented, along with promising hybrid mode-locking results of 124fs....

  12. Monolithic Hybrid and Passive Mode-Locked 40GHz Quantum Dot Laser Diodes

    DEFF Research Database (Denmark)

    Thompson, M. G.; Larsson, David; Rae, A. R.;

    2006-01-01

    For the first time hybrid and passive mode-locking jitter performance is investigated in 40GHz quantum-dot mode-locked lasers. Record low passive mode-locking jitter of 219fs is presented, along with promising hybrid mode-locking results of 124fs.......For the first time hybrid and passive mode-locking jitter performance is investigated in 40GHz quantum-dot mode-locked lasers. Record low passive mode-locking jitter of 219fs is presented, along with promising hybrid mode-locking results of 124fs....

  13. Single and multiple molecular beacon probes for DNA hybridization studies on a silica glass surface

    Science.gov (United States)

    Fang, Xiaohong; Liu, Xiaojing; Tan, Weihong

    1999-05-01

    Surface immobilizable molecular beacons have been developed for DNA hybridization studies on a silica glass plate. Molecular beacons are a new class of oligonucleotide probes that have a loop-and-stem structure with a fluorophore and a quencher attached to the two ends of the stem. They only emit intense fluorescence when hybridize to their target molecules. This provides an excellent selectivity for the detection of DNA molecules. We have designed biotinylated molecular beacons which can be immobilized onto a solid surface. The molecular beacon is synthesized using DABCYL as the quencher and an optical stable dye, tetramethylrhodamine, as the fluorophore. Mass spectrometry is used to confirm the synthesized molecular beacon. The molecular beacons have been immobilized onto a silica surface through biotin-avidin binding. The surface immobilized molecular beacons have been used for the detection of target DNA with subnanomolar analytical sensitivity. have also immobilized two different molecular beacons on a silica surface in spatially resolved microscopic regions. The hybridization study of these two different molecular beacon probes has shown excellent selectivity for their target sequences. The newly designed molecular beacons are intended for DNA molecular interaction studies at an interface and for the development of ultrasensitive DNA sensors for a variety of applications including disease diagnosis, disease mechanism studies, new drug development, and in the investigation of molecular interactions between DNA molecules and other interesting biomolecules.

  14. Plasma-deposited hybrid silica membranes with a controlled retention of organic bridges

    Energy Technology Data Exchange (ETDEWEB)

    Ngamou, P.H.T.; Creatore, M. [Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Overbeek, J.P.; Kreiter, R.; Van Veen, H.M.; Vente, J.F. [ECN, Energy research Centre of the Netherlands, Petten (Netherlands); Wienk, I.M.; Cuperus, P.F. [SolSep BV, Apeldoorn (Netherlands)

    2013-03-05

    Hybrid organically bridged silica membranes are suitable for energy-efficient molecular separations under harsh industrial conditions. Such membranes can be useful in organic solvent nanofiltration if they can be deposited on flexible, porous and large area supports. Here, we report the proof of concept for applying an expanding thermal plasma to the synthesis of perm-selective hybrid silica films from an organically bridged monomer, 1,2-bis(triethoxysilyl)ethane. This membrane is the first in its class to be produced by plasma enhanced chemical vapor deposition. By tuning the plasma and process parameters, the organic bridging groups could be retained in the separating layer. This way, a defect free film could be made with pervaporation performances of an n-butanol-water mixture comparable with those of conventional ceramic supported membranes made by sol-gel technology (i.e. a water flux of [similar]1.8 kg m'-{sup 2} h{sup -1}, a water concentration in the permeate higher than 98% and a separation factor of >1100). The obtained results show the suitability of expanding thermal plasma as a technology for the deposition of hybrid silica membranes for molecular separations.

  15. Direct-writing of PbS nanoparticles inside transparent porous silica monoliths using pulsed femtosecond laser irradiation

    Science.gov (United States)

    Chahadih, Abdallah; El Hamzaoui, Hicham; Bernard, Rémy; Boussekey, Luc; Bois, Laurence; Cristini, Odile; Le Parquier, Marc; Capoen, Bruno; Bouazaoui, Mohamed

    2011-10-01

    Pulsed femtosecond laser irradiation at low repetition rate, without any annealing, has been used to localize the growth of PbS nanoparticles, for the first time, inside a transparent porous silica matrix prepared by a sol-gel route. Before the irradiation, the porous silica host has been soaked within a solution containing PbS precursors. The effect of the incident laser power on the particle size was studied. X-ray diffraction was used to identify the PbS crystallites inside the irradiated areas and to estimate the average particle size. The localized laser irradiation led to PbS crystallite size ranging between 4 and 8 nm, depending on the incident femtosecond laser power. The optical properties of the obtained PbS-silica nanocomposites have been investigated using absorption and photoluminescence spectroscopies. Finally, the stability of PbS nanoparticles embedded inside the host matrices has been followed as a function of time, and it has been shown that this stability depends on the nanoparticle mean size.

  16. Electrochemical co-deposition of conductive polymer-silica hybrid thin films.

    Science.gov (United States)

    Raveh, Moran; Liu, Liang; Mandler, Daniel

    2013-07-14

    Conductive polymers, such as polypyrrole (ppy), have been the subject of numerous studies due to their promising applications in organic solar cells, flexible electronics, electrochromic devices, super capacitors, etc. Yet, their application is still limited as a result of poor processability. Silica has been reported to improve the mechanical strength and adhesion of conductive polymer films. In this work, we propose a controllable electrochemical approach for preparing ppy-silica hybrid thin films from a solution containing both pyrrole and silane monomers. It is known that pyrrole can be electropolymerised using anodic potentials, while silica can be electrodeposited under cathodic potentials. Thus, we studied the formation of ppy-silica hybrid thin films on a stainless steel surface by applying alternating potentials, i.e. cathodic followed by anodic pulses (denoted C + A) or anodic followed by cathodic pulses (denoted A + C). We show that by controlling the deposition potential and time for the cathodic and anodic pulses, the film thickness and composition can be manipulated well as analysed using profilometry and EDX. The element depth profile of the films was characterized using secondary ion mass spectroscopy (SIMS). In essence, for the C + A process, pyrrole diffuses through the cathodically electrodeposited wet silica gel layer and undergoes anodic polymerisation on the substrate, while for the A + C process, silane can be electrodeposited both on top of the anodically electrodeposited conductive ppy films as well as on the stainless steel through the pinholes in the ppy film. This offers a simple approach for tuning the structure of conductive polymer-sol-gel composite films.

  17. Sonic spray ionization technology: performance study and application to a LC/MS analysis on a monolithic silica column for heroin impurity profiling.

    Science.gov (United States)

    Dams, Riet; Benijts, Tom; Günther, Wolfgang; Lambert, Willy; De Leenheer, André

    2002-07-01

    Sonic spray (SS) ionization is a relatively novel atmospheric pressure ionization technique for LC/MS, based on the principle of "spray ionization", which only recently became commercially available. In this paper, we evaluate the performance of this ion source as an interface for LC/MS in comparison with the more traditional and better studied pneumatically assisted electrospray or ion spray (IS). The effect of organic modifiers, volatile acids, and buffer systems in the LC eluent on the ionization efficiency of both interfaces is described and some possible explanations for the observed phenomena are highlighted. We could conclude that the presence of organic solvents gradually increased the ionization efficiency for IS and SS, while volatile acids or buffers gave a significant signal suppression. Furthermore, we present the application of the sonic spray interface to a fast LC/MS analysis, for the simultaneous determination of the seven prime opium alkaloids in heroin impurity profiling. Chromatographic separation is performed in 5 min on a monolithic silica column (Chromolith Performance) with a gradient elution system and an optimized flow of 5 mL/min. By means of a postcolumn split of approximately 1/20, a coupling between the fast LC system and the mass spectrometer is made. The method is validated and successfully applied to the analysis of real-time seized heroin street samples.

  18. AFM PeakForce QNM mode: Evidencing nanometre-scale mechanical properties of chitin-silica hybrid nanocomposites.

    Science.gov (United States)

    Smolyakov, G; Pruvost, S; Cardoso, L; Alonso, B; Belamie, E; Duchet-Rumeau, J

    2016-10-20

    PeakForce Quantitative Nanomechanical Mapping (QNM) AFM mode was used to explore the mechanical properties of textured chitin-silica hybrid films at the nanoscale. The influence of the force applied by the tip on the sample surface was studied for standard homogeneous samples, for chitin nanorods and for chitin-silica hybrid nanocomposites. Thick films of superimposed chitin nanorods showed a monotonous increase of DMT modulus (based on the Derjaguin-Muller-Toporov model) owing to an increase in modulus at the interface between nanorods due to geometrical constraints of the AFM acquisition. A similar variation of DMT modulus was obtained for chitin-silica hybrid thick films related to mechanical strengthening induced by the presence of silica. This work revealed the role of the organic-inorganic interface, at the nanoscale, in the mechanical behaviour of textured materials using PeakForce QNM mode, with optimized analysis conditions.

  19. Synthesis of organic-inorganic hybrid microspheres and the corresponding mesoporous silica nanoparticles.

    Science.gov (United States)

    Liu, Bin; Fu, Xiaomeng; Wang, Dan; Zhang, Wei; Yang, Xinlin

    2013-12-01

    Poly(methacrylic acid-co-3-(methacryloxy)propyltrimethoxysilane) (P(MAA-co-MPS)) organic-inorganic hybrid microspheres were prepared by distillation-precipitation copolymerization of MAA and MPS in acetonitrile in absence of any surfactant and additive. The resultant hybrids had a spherical shape when the MPS inorganic precursor was varied from 0% to 60% in the comonomers during the polymerization. The hybrid microspheres can be facilely cross-linked via the hydrolysis of methoxy groups of polyMPS network and further self-condensation of the hydroxyl groups of silanols. As a result, the hybrid microspheres were facilely converted to mesoporous silica particles via the removal of the organic component through calcination. The narrow dispersed mesoporous silica had a high surface area of 554.2 m(2)/g as well as the average pore size of 8 nm and pore volume of 0.24 cm(3)/g. The corresponding microspheres were characterized by TEM, FT-IR, TGA, and nitrogen sorption-desorption.

  20. Biomimetic synthesis of raspberry-like hybrid polymer-silica core-shell nanoparticles by templating colloidal particles with hairy polyamine shell.

    Science.gov (United States)

    Pi, Mengwei; Yang, Tingting; Yuan, Jianjun; Fujii, Syuji; Kakigi, Yuichi; Nakamura, Yoshinobu; Cheng, Shiyuan

    2010-07-01

    The nanoparticles composed of polystyrene core and poly[2-(diethylamino)ethyl methacrylate] (PDEA) hairy shell were used as colloidal templates for in situ silica mineralization, allowing the well-controlled synthesis of hybrid silica core-shell nanoparticles with raspberry-like morphology and hollow silica nanoparticles by subsequent calcination. Silica deposition was performed by simply stirring a mixture of the polymeric core-shell particles in isopropanol, tetramethyl orthosilicate (TMOS) and water at 25 degrees C for 2.5h. No experimental evidence was found for nontemplated silica formation, which indicated that silica deposition occurred exclusively in the PDEA shell and formed PDEA-silica hybrid shell. The resulting hybrid silica core-shell particles were characterized by transmission electron microscopy (TEM), thermogravimetry, aqueous electrophoresis, and X-ray photoelectron spectroscopy. TEM studies indicated that the hybrid particles have well-defined core-shell structure with raspberry morphology after silica deposition. We found that the surface nanostructure of hybrid nanoparticles and the composition distribution of PDEA-silica hybrid shell could be well controlled by adjusting the silicification conditions. These new hybrid core-shell nanoparticles and hollow silica nanoparticles would have potential applications for high-performance coatings, encapsulation and delivery of active organic molecules.

  1. Hybrid Organometallic-Inorganic Nanomaterial: Acetyl Ferrocene Schiff base Immobilized on Silica Coated Magnetite Nanoparticles

    Directory of Open Access Journals (Sweden)

    M. Masteri-Farahani

    2015-10-01

    Full Text Available In  this  work,  a  new  hybrid  organometallic-inorganic  hybrid nanomaterial was prepared by immobilization of acetyl ferrocene on the  surface  of magnetite  nanoparticles. Covalent  grafting of silica coated magnetite nanoparticles (SCMNPs with 3-aminopropyl triethoxysilane gave aminopropyl-modified magnetite nanoparticles (AmpSCMNPs. Then, Schiff base condensation  of AmpSCMNPs with acetyl  ferrocene resulted in the preparation of acferro-SCMNPs hybrid nanomaterial. Characterization of the prepared nanomaterial was performed with different physicochemical methods such as Fourier transform infrared spectroscopy (FT-IR, X-ray diffraction (XRD, vibrating sample magnetometry (VSM, thermogravimetric analysis (TGA, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. VSM analysis showed superparamagnetic properties of the prepared nanomaterial and TEM and SEM analyses indicated the relatively spherical nanoparticles with 15 nm average size.

  2. Influence of silica-based hybrid material on the gas permeability of hardened cement paste

    Science.gov (United States)

    Li, R.; Hou, P.; Xie, N.; Zhou, Z.; Cheng, X.

    2017-03-01

    Surface treatment is one of the most effective ways to elongate the service life of concrete. The surface treatment agents, including organic and inorganic types, have been intensively studied. In this paper, the silica-based hybrid nanocomposite, which take advantages of both organic and inorganic treatment agents, was synthesized and used for surface treatment of hardened cement-based material. The effectiveness of organic and inorganic hybrid nanocomposite was evaluated through investigations on the gas permeability of cement-based materials. The results showed that SiO2/PMHS hybrid nanocomposite can greatly decrease the gas transport properties of hardened cement-based materials and has a great potential for surface treatment of cementitious materials.

  3. Lanthano phosphomolybdate-decorated silica nanoparticles: novel hybrid materials with photochromic properties.

    Science.gov (United States)

    Pinto, Tânia V; Fernandes, Diana M; Pereira, Clara; Guedes, Alexandra; Blanco, Ginesa; Pintado, Jose M; Pereira, Manuel F R; Freire, Cristina

    2015-03-14

    Novel photochromic hybrid nanomaterials were prepared through the immobilization of the lacunary Keggin-type phosphomolybdate (TBA4H3[PMo11O39]·xH2O, denoted as PMo11) and sandwich-type lanthano phosphomolybdates (K11[Ln(III)(PMo11O39)2]·xH2O, denoted as Ln(PMo11)2, where Ln(III) = Sm, Eu, Gd, Tb and Dy) onto positively-charged functionalized silica nanoparticles. The functionalized silica nanoparticles were prepared by a one-step co-condensation route between tetraethyl orthosilicate and dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride, presenting an average particle size of 95 ± 26 nm, a spherical morphology and a pore diameter of 13.7 nm. All characterization techniques proved the successful immobilization of the phosphomolybdates. The photochromic properties of the resulting hybrid nanomaterials in the solid state were evaluated by UV-Vis spectroscopy and colorimetry. All materials revealed promising photochromic properties under UV irradiation (λ = 254 nm). The lacunary phosphomolybdate anchored onto the silica nanoparticles, C18-SiO2@PMo11, showed the best photoswitching properties, with the color changing from green to dark-blue (ΔE* = 26.8). Among the Ln(PMo11)2-based hybrid nanomaterials, those containing higher Mo loadings--Eu(III)- and Tb(III)-based samples--presented more significant color changes from green to dark-blue (ΔE* = 18.8-18.9). These results revealed that the optical properties of the as-prepared hybrid nanomaterials did not depend directly on the type of Ln(III) cation, but only on the amount of Mo, which was the target element responsible for the photochromic behavior.

  4. Mass transfer of large molecules through collagen and collagen-silica hybrid membranes

    Science.gov (United States)

    Jofre-Lora, Pedro

    Diabetes is a growing concern in the United States and around the world that must be addressed through new treatment options. Current standard treatment options of diabetes are limiting and have tremendous impacts on patient's lives. Emerging therapies, such as the implantation of encapsulated islets, are promising treatment options, but have not yet materialized due to unsolved problems with material properties. Hybrid silica-collagen membranes address some of these unsolved problems and are a promising material for cell encapsulation. However, the mass transfer properties of large molecules, such as insulin, TNF-alpha, IL1beta, and other important proteins in the etiology of diabetes, through these hybrid membranes are poorly characterized. In order to begin characterizing these properties, a device was constructed to accurately and efficiently measure the mass transfer of other similar large molecules, fluorescein isothiocyanate dextrans (FITC-dextran), through collagen-silica hybrid membranes. The device was used to measure diffusion coefficients of 4, 20, 40, and 150 kDa FITC-dextrans through non-silicified and silicified samples of 200 and 1000 Pa porcine skin collagen. Diffusion coefficients were found to be in the 10-7-10-6 cm2s -1 range, which is in agreement with previously published data for similar molecules through similar hydrogels. The effects of collagen stiffness, FITC-dextran molecular weight, and silicification treatment on diffusion were investigated. It was found that collagen stiffness and FITC-dextran molecular weight had a negative correlation with diffusion, whereas silicification treatment had no global impact on diffusion. The device created, and the results of this preliminary investigation, can be used to develop collagen-silica hybrid membranes as an alternative material for cell encapsulation in a forward-design manner.

  5. Durable flame retardant finish for silk fabric using boron hybrid silica sol

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qiang-hua; Gu, Jiali; Chen, Guo-qiang [National Engineering Laboratory for Modern Silk, Soochow University (China); Xing, Tie-ling, E-mail: xingtieling@suda.edu.cn [National Engineering Laboratory for Modern Silk, Soochow University (China); Jiangsu HuaJia Group (China)

    2016-11-30

    Highlights: • Highly homogeneous boron hybrid silica sol flame retardant system was prepared through sol-gel method. • The silk samples treated and cross-linked by this hybrid sol and BTCA solution showed a higher limiting oxygen index (LOI) more than 31.0% and a better washing durability for more than 30 times washing. • The smoke suppression, combustion performance and thermal stability properties of the treated samples have a significant improvement. - Abstract: A hybrid silica sol was prepared via sol gel method using tetraethoxysilane (TEOS) as a precursor and boric acid (H{sub 3}BO{sub 3}) as flame retardant additive and then applied to silk fabric. In order to endow silk fabric with durable flame retardancy, 1,2,3,4-butanetetracarboxylic acid (BTCA) was used as cross-linking agent for the sake of strong linkage formation between the hybrid silica sol and silk fabric. The FT-IR and XPS analysis demonstrated the Si-O-B formation in the sol system, as well as the linkage between the sol and silk after the treatment. The limiting oxygen index (LOI) and smoke density test indicated good flame retardancy and smoke suppression of the treated silk fabrics. The micro calorimeter combustion (MCC) test and thermo gravimetric (TG) analysis showed that the treated samples had less weight loss in the high temperature and lower heat release rate when burning. The washing durability evaluation results indicated that there was a distinct improvement for the silk samples treated with BTCA even after 30 times washing. In addition, the influence of the processing order of BTCA and silica sol treatment on the limiting oxygen index (LOI) of the finished silk fabric was also investigated. And the results demonstrated that the sample treated with BTCA first and then with the silica sol exhibited better LOI value (32.3%) than that of the sample by the conversed treatment order. Moreover the tensile property of treated samples was nearly unchanged, but the handle of sol treated

  6. Ordered mesoporous polymer-silica hybrid nanoparticles as vehicles for the intracellular controlled release of macromolecules.

    Science.gov (United States)

    Kim, Tae-Wan; Slowing, Igor I; Chung, Po-Wen; Lin, Victor Shang-Yi

    2011-01-25

    A two-dimensional hexagonal ordered mesoporous polymer-silica hybrid nanoparticle (PSN) material was synthesized by polymerization of acrylate monomers on the surface of SBA-15 mesoporous silica nanoparticles. The structure of the PSN material was analyzed using a series of different techniques, including transmission electron microscopy, powder X-ray diffraction, and N(2) sorption analysis. These structurally ordered mesoporous polymer-silica hybrid nanoparticles were used for the controlled release of membrane-impermeable macromolecules inside eukaryotic cells. The cellular uptake efficiency and biocompatibility of PSN with human cervical cancer cells (HeLa) were investigated. Our results show that the inhibitory concentration (IC(50)) of PSN is very high (>100 μg/mL per million cells), while the median effective concentration for the uptake (EC(50)) of PSN is low (EC(50) = 4.4 μg/mL), indicating that PSNs are fairly biocompatible and easily up-taken in vitro. A membrane-impermeable macromolecule, 40 kDa FITC-Dextran, was loaded into the mesopores of PSNs at low pH. We demonstrated that the PSN material could indeed serve as a transmembrane carrier for the controlled release of FITC-Dextran at the pH level inside live HeLa cells. We believe that further developments of this PSN material will lead to a new generation of nanodevices for intracellular controlled delivery applications.

  7. Mechanical properties of composites made of hybrid fabric impregnated with silica nanoparticles and epoxy resin

    Science.gov (United States)

    Kordani, N.; Alizadeh, M.; Lohrasby, F.; Khajavi, R.; Baharvandi, H. R.; Rezanejad, M.; Ahmadzadeh, M.

    2017-09-01

    In this study, the mechanical properties of composites will be examined which were made from Kenaf and hybrid fabric with a simple structure that was coated with epoxy resin and nano silica particles. This fabric cotton has a different situation in terms of yarn score and the type of fiber that is used in textiles. Nano silica particles of 200 nm, polyethylene glycol with 200 molecular weights and ethanol with mechanical weight molecular with ratio of 6:1 will be mixed. Suspension of 60% was chosen according to the silica particles. The D6264 standard test for concentrated force was carried out through the cone edge to determine the strength of each of the samples. Increasing of resistance against penetration in the Kenaf samples from the raw until impregnated with the shear thickening fluid is less than the hybrid samples. Slippage of the fibers with the change of round edge indenter to cone edge indenter has changed. Penetration by cone edge to the cloth is done with lower force and it shows the effect of slippage of fibers on the resistance of the penetration. Samples impregnated with the shear thickening fluid in comparison with epoxy resin have lower resistance. Slippage of natural fibers in comparison with synthetic fibers is lower and on the other hand the average of friction between fibers in the natural fibers is more than synthetic fibers.

  8. Effect of Silane Treatment on Hybridized Use of Short Cellulose Fibers and Silica Particles for Natural Rubber Reinforcement

    Science.gov (United States)

    Lopattananon, Natinee; Jitkalong, Dolmalik; Seadan, Manus; Sakai, Tadamoto

    Processability, swelling and tensile properties of natural-rubber-based hybrid composites prepared by mixing short cellulose fibers and fine silica particles of equal contents with total loading of 20 phr using a two-roll mill were analyzed. Their properties were compared with those of natural rubber reinforced with single filler (silica or cellulose fiber) and corresponding unfilled natural rubber. The tensile test showed the reinforcing effect of both single filler system and hybrid filler system in relation to natural rubber. The tensile modulus and tensile strength of hybrid composites generally laid between those of fiber-reinforced and silica-reinforced natural rubber composites, whereas the elongation at break of hybrid composites was equal to that of single filler reinforcement system. The Mooney viscosity of silica-filled compound was much higher than that of unfilled natural rubber and short fiber-filled compounds, and was significantly reduced when hybridized fillers were used. Furthermore, a silane coupling agent, Si 69, was used to modify the surface properties of cellulose fibers and silica particles. Three microscopic evaluation techniques, that is, elemental X-ray mapping (EDX), 3D microfocus X-ray scanning, and N-ARC methods were applied to investigate the filler dispersion/mixing effects. It was found that both of the fillers were more homogeneously dispersed in the hybrid composites, and the affinity between the fillers and natural rubber was improved after the silane treatment. The results from this work suggested that the better dispersion of short cellulose fiber/silica hybrid fillers had great advantages in rubber processing, and allowed for equal or higher composite strength compared to a simply silica-filled composite system.

  9. Lighting up silica nanotubes transcribed from the submicron structure of a metal-peptide hybrid

    Science.gov (United States)

    Pu, Fang; Ren, Jinsong

    2013-09-01

    Fluorescent silica nanotubes are attracting increasing interest because of their versatile applicability in a range of diverse fields. By using sol-gel transcription of tetraethylorthosilicate (TEOS) from various soft templates, silica nanotubes can be conveniently prepared. Metal-peptide hybrids with well-defined nanostructures and outstanding functionalities are very interesting candidates to serve as templates. Herein, we demonstrate that glutathione (GSH) can act as a building block for a bioinspired structure with dimensions down to the nanoscale, based on specific interactions between metal ions and the peptide. Congo red is able to selectively stain the nanofibres obtained, and appears apple-green in colour, implying that Congo red is promising to serve as an effective and convenient probe for determining the self-assembly of GSH and copper ions. Furthermore, silica nanotubes are synthesized using the nanofibres as a template in a very simple way. The silica nanotubes can be lit up by biomolecule-templated metal nanoparticles or nanoclusters and emit bright fluorescence. This work will certainly open up new opportunities in fabricating a broad range of nanostructured materials with versatile functionalities.

  10. Sol-gel network silica/modified montmorillonite clay hybrid nanocomposites for hydrophobic surface coatings.

    Science.gov (United States)

    Meera, Kamal Mohamed Seeni; Sankar, Rajavelu Murali; Murali, Adhigan; Jaisankar, Sellamuthu N; Mandal, Asit Baran

    2012-02-01

    Sol-gel silica/nanoclay composites were prepared through sol-gel polymerization technique using tetraethylorthosilicate precursor and montmorillonite (MMT) clay in aqueous media. In this study, both montmorillonite-K(+) and organically modified MMT (OMMT) clays were used. The prepared composites were coated on glass substrate by making 1 wt% solution in ethyltrichlorosilane. The incorporation of nanoclay does not alter the intensity of characteristic Si-O-Si peak of silica network. Thermogravimetric studies show that increasing clay content increased the degradation temperature of the composites. Differential scanning calorimetry (DSC) results of organically modified MMT nanoclay incorporated composite show a shift in the melting behavior up to 38°C. From DSC thermograms, we observed that the ΔH value decreased with increasing clay loading. X-ray diffraction patterns prove the presence of nanoclay in the composite and increase in the concentration of organically modified nanoclay from 3 to 5 wt% increases the intensity of the peak at 2θ=8° corresponds to OMMT. Morphology of the control silica gel composite was greatly influenced by the incorporation of OMMT. The presence of nanoclay changed the surface of control silica gel composite into cleaved surface with brittle in nature. Contact angle measurements were done for the coatings to study their surface behavior. These hybrid coatings on glass substrate may have applications for hydrophobic coatings on leather substrate.

  11. Durable flame retardant finish for silk fabric using boron hybrid silica sol

    Science.gov (United States)

    Zhang, Qiang-hua; Gu, Jiali; Chen, Guo-qiang; Xing, Tie-ling

    2016-11-01

    A hybrid silica sol was prepared via sol gel method using tetraethoxysilane (TEOS) as a precursor and boric acid (H3BO3) as flame retardant additive and then applied to silk fabric. In order to endow silk fabric with durable flame retardancy, 1,2,3,4-butanetetracarboxylic acid (BTCA) was used as cross-linking agent for the sake of strong linkage formation between the hybrid silica sol and silk fabric. The FT-IR and XPS analysis demonstrated the Si-O-B formation in the sol system, as well as the linkage between the sol and silk after the treatment. The limiting oxygen index (LOI) and smoke density test indicated good flame retardancy and smoke suppression of the treated silk fabrics. The micro calorimeter combustion (MCC) test and thermo gravimetric (TG) analysis showed that the treated samples had less weight loss in the high temperature and lower heat release rate when burning. The washing durability evaluation results indicated that there was a distinct improvement for the silk samples treated with BTCA even after 30 times washing. In addition, the influence of the processing order of BTCA and silica sol treatment on the limiting oxygen index (LOI) of the finished silk fabric was also investigated. And the results demonstrated that the sample treated with BTCA first and then with the silica sol exhibited better LOI value (32.3%) than that of the sample by the conversed treatment order. Moreover the tensile property of treated samples was nearly unchanged, but the handle of sol treated samples obviously decreased.

  12. Medical applications of organic-inorganic hybrid materials within the field of silica-based bioceramics.

    Science.gov (United States)

    Vallet-Regí, María; Colilla, Montserrat; González, Blanca

    2011-02-01

    Research on bioceramics has evolved from the use of inert materials for mere substitution of living tissues towards the development of third-generation bioceramics aimed at inducing bone tissue regeneration. Within this context hybrid bioceramics have remarkable features resulting from the synergistic combination of both inorganic and organic components that make them suitable for a wide range of medical applications. Certain bioceramics, such as ordered mesoporous silicas, can exhibit different kind of interaction with organic molecules to develop different functions. The weak interaction of these host matrixes with drug molecules confined in the mesoporous channels allows these hybrid systems to be used as controlled delivery devices. Moreover, mesoporous silicas can be used to fabricate three (3D)-dimensional scaffolds for bone tissue engineering. In this last case, different osteoinductive agents (peptides, hormones and growth factors) can be strongly grafted to the bioceramic matrix to act as attracting signals for bone cells to promote bone regeneration process. Finally, recent research examples of organic-inorganic hybrid bioceramics, such as stimuli-responsive drug delivery systems and nanosystems for targeting of cancer cells and gene transfection, are also tackled in this tutorial review (64 references).

  13. Nanocellulose Derivative/Silica Hybrid Core-Shell Chiral Stationary Phase: Preparation and Enantioseparation Performance

    Directory of Open Access Journals (Sweden)

    Xiaoli Zhang

    2016-05-01

    Full Text Available Core-shell silica microspheres with a nanocellulose derivative in the hybrid shell were successfully prepared as a chiral stationary phase by a layer-by-layer self-assembly method. The hybrid shell assembled on the silica core was formed using a surfactant as template by the copolymerization reaction of tetraethyl orthosilicate and the nanocellulose derivative bearing triethoxysilyl and 3,5-dimethylphenyl groups. The resulting nanocellulose hybrid core-shell chiral packing materials (CPMs were characterized and packed into columns, and their enantioseparation performance was evaluated by high performance liquid chromatography. The results showed that CPMs exhibited uniform surface morphology and core-shell structures. Various types of chiral compounds were efficiently separated under normal and reversed phase mode. Moreover, chloroform and tetrahydrofuran as mobile phase additives could obviously improve the resolution during the chiral separation processes. CPMs still have good chiral separation property when eluted with solvent systems with a high content of tetrahydrofuran and chloroform, which proved the high solvent resistance of this new material.

  14. Monitoring DNA hybridization and thermal dissociation at the silica/water interface using resonantly enhanced second harmonic generation spectroscopy.

    Science.gov (United States)

    Azam, Md Shafiul; Gibbs-Davis, Julianne M

    2013-09-03

    The immobilization of oligonucleotide sequences onto glass supports is central to the field of biodiagnostics and molecular biology with the widespread use of DNA microarrays. However, the influence of confinement on the behavior of DNA immobilized on silica is not well understood owing to the difficulties associated with monitoring this buried interface. Second harmonic generation (SHG) is an inherently surface specific technique making it well suited to observe processes at insulator interfaces like silica. Using a universal 3-nitropyrolle nucleotide as an SHG-active label, we monitored the hybridization rate and thermal dissociation of a 15-mer of DNA immobilized at the silica/aqueous interface. The immobilized DNA exhibits hybridization rates on the minute time scale, which is much slower than hybridization kinetics in solution but on par with hybridization behavior observed at electrochemical interfaces. In contrast, the thermal dissociation temperature of the DNA immobilized on silica is on average 12 °C lower than the analogous duplex in solution, which is more significant than that observed on other surfaces like gold. We attribute the destabilizing affect of silica to its negatively charged surface at neutral pH that repels the hybridizing complementary DNA.

  15. Structural effect of monomer type on properties of copolyimides and copolyimide-silica hybrid materials

    Directory of Open Access Journals (Sweden)

    Kizilkaya Canan

    2015-01-01

    Full Text Available In this work, the effect of two different diamine monomers, containing phosphine oxide, on thermal, mechanical and morphological properties of copolyimides and their hybrid materials was investigated. Gas separation properties of the synthesized copolyimides were also analysed. Two different diamine monomers with phosphine oxide were bis(3-aminophenyl phenylphosphine oxide (BAPPO and bis(3-aminophenoxy-4-phenyl phenylphosphine oxide (m-BAPPO. In the synthesis of copolyimides 3,3’-diamino-diphenyl sulfone (DDS was also used as the diamine, as well as 2,2’-bis(3,4-dicarboxyphenylhexafluoropropane dianhydride (6FDA. Copolyimide films were prepared by thermal imidization. Hybrid materials containing 5 % SiO2 were synthesised further by sol-gel technique. The Fourier-transform infrared spectroscopy (FTIR, Nuclear magnetic resonance spectroscopy (NMR confirmed the expected structure. Dynamic mechanical analysis (DMA demonstrated that m-BAPPO based copolyimides had lower glass transition temperatures (Tg than BAPPO based copolyimides. m-BAPPO containing copolyimide without silica shifted the thermal decomposition temperature to a higher value. The moduli and strength values of BAPPO diamine containing copolyimide and its hybrid were higher than those of m-BAPPO containing materials. The contact angle measurements showed the hydrophobicity. Scanning electron microscope (SEM analysis exhibited the silica particles dispersion in the copolyimides. These copolyimides may be used in the coating industry. The CO2 permeability and the permselectivity were the highest among the other values in this study, when m-BAPPO containing copolyimide in the absence of silica was used. The gas permeabilities obtained from this work were in this decreasing order: PCO2 > PO2 > PN2.

  16. Preparation and properties of poly(vinylidene fluoride nanocomposites blended with graphene oxide coated silica hybrids

    Directory of Open Access Journals (Sweden)

    Q. Fu

    2012-04-01

    Full Text Available Graphene oxide coated silica hybirds (SiO2-GO were fabricated through electrostatic assembly in this work, then blended with poly(vinylidene fluoride (PVDF by solution mixing to make PVDF nanocomposites. The interfacial interaction was investigated by scanning electron microscopy (SEM, polarized optical microscopy (POM and Fourier transform infrared spectroscopy (FTIR. The results showed that the interfacial interaction was enhanced by adding of SiO2-GO and strong hydrogen bonds were observed. The as-made nanocomposites were investigated using standard tensile test and dynamic mechanical analysis (DMA measurements, mechanical properties of PVDF with SiO2-GO hybrids showed limited improvement.

  17. A novel hybrid metal-organic framework-polymeric monolith for solid-phase microextraction.

    Science.gov (United States)

    Lin, Chen-Lan; Lirio, Stephen; Chen, Ya-Ting; Lin, Chia-Her; Huang, Hsi-Ya

    2014-03-17

    This study describes the fabrication of a novel hybrid metal-organic framework- organic polymer (MOF-polymer) for use as a stationary phase in fritless solid-phase microextraction (SPME) for validating analytical methods. The MOF-polymer was prepared by using ethylene dimethacrylate (EDMA), butyl methacrylate (BMA), and an imidazolium-based ionic liquid as porogenic solvent followed by microwave-assisted polymerization with the addition of 25 % MOF. This novel hybrid MOF-polymer was used to extract penicillin (penicillin G, penicillin V, oxacillin, cloxacillin, nafcillin, dicloxacillin) under different conditions. Quantitative analysis of the extracted penicillin samples using the MOF-organic polymer for SPME was conducted by using capillary electrochromatography (CEC) coupled with UV analysis. The penicillin recovery was 63-96.2 % with high reproducibility, sensitivity, and reusability. The extraction time with the proposed fabricated SPME was only 34 min.

  18. Direct observation of the spatial distribution of samarium ions in alumina-silica macroporous monoliths by laser scanning confocal microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Murai, Shunsuke [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Fujita, Koji [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan)]. E-mail: fujita@sung7.kuic.kyoto-u.ac.jp; Nakanishi, Kazuki [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Hirao, Kazuyuki [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan)

    2006-02-09

    We have investigated the spatial distribution of Sm{sup 2+} inside macroporous alumina-silica (Al{sub 2}O{sub 3}-SiO{sub 2}) glasses having three-dimensionally interconnected skeletons. The Sm{sup 2+}-doped Al{sub 2}O{sub 3}-SiO{sub 2} glasses are prepared via an alkoxy-derived sol-gel route in the presence of poly (ethylene oxide) and SmCl{sub 3}.6H{sub 2}O. The well-defined macroporous morphology is obtained by the concurrence of the phase separation and the sol-gel transition. The reduction of Sm{sup 3+} to Sm{sup 2+} is accomplished by heat treatment under a reducing atmosphere. Two-dimensional images of the fluorescence due to the 4f-4f transition of Sm{sup 2+} with the aid of a laser scanning confocal microscope reveal the spatially uniform dispersion of Sm{sup 2+} inside the Al{sub 2}O{sub 3}-SiO{sub 2} skeleton.

  19. Chromatographic assessment of two hybrid monoliths prepared via epoxy-amine ring-opening polymerization and methacrylate-based free radical polymerization using methacrylate epoxy cyclosiloxane as functional monomer.

    Science.gov (United States)

    Wang, Hongwei; Ou, Junjie; Lin, Hui; Liu, Zhongshan; Huang, Guang; Dong, Jing; Zou, Hanfa

    2014-11-07

    Two kinds of hybrid monolithic columns were prepared by using methacrylate epoxy cyclosiloxane (epoxy-MA) as functional monomer, containing three epoxy moieties and one methacrylate group. One column was in situ fabricated by ring-opening polymerization of epoxy-MA and 1,10-diaminodecane (DAD) using a porogenic system consisting of isopropanol (IPA), H2O and ethanol at 65°C for 12h. The other was prepared by free radical polymerization of epoxy-MA and ethylene dimethacrylate (EDMA) using 1-propanol and 1,4-butanediol as the porogenic solvents at 60°C for 12h. Two hybrid monoliths were investigated on the morphology and chromatographic assessment. Although two kinds of monolithic columns were prepared with epoxy-MA, their morphologies looked rather different. It could be found that the epoxy-MA-DAD monolith possessed higher column efficiencies (25,000-34,000plates/m) for the separation of alkylbenzenes than the epoxy-MA-EDMA monolith (12,000-13,000plates/m) in reversed-phase nano-liquid chromatography (nano-LC). Depending on the remaining epoxy or methacrylate groups on the surface of two pristine monoliths, the epoxy-MA-EDMA monolith could be easily modified with 1-octadecylamine (ODA) via ring-opening reaction, while the epoxy-MA-DAD monolith could be modified with stearyl methacrylate (SMA) via free radical reaction. The chromatographic performance for the separation of alkylbenzenes on SMA-modified epoxy-MA-DAD monolith was remarkably improved (42,000-54,000 plates/m) when compared with that on pristine epoxy-MA-DAD monolith, while it was not obviously enhanced on ODA-modified epoxy-MA-EDMA monolith when compared with that on pristine epoxy-MA-EDMA monolith. The enhancement of the column efficiency of epoxy-MA-DAD monolith after modification might be ascribed to the decreased mass-transfer resistence. The two kinds of hybrid monoliths were also applied for separations of six phenols and seven basic compounds in nano-LC. Copyright © 2014 Elsevier B.V. All

  20. Internalization of silica nanoparticles into fluid liposomes: formation of interesting hybrid colloids.

    Science.gov (United States)

    Michel, Raphael; Kesselman, Ellina; Plostica, Tobias; Danino, Dganit; Gradzielski, Michael

    2014-11-10

    The formation of hybrid materials consisting of membrane-coated silica nanoparticles (SiNPs) concentrated within small unilamellar vesicles (SUVs) of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) is described. They are formed by a simple self-assembly process resulting from invagination of the SiNPs into the SUVs and subsequent vesicle fusion, thereby retaining an almost constant size. This process was followed under conditions where it proceeds slowly and could be analyzed in structural detail. The finally formed well-defined SiNP-filled vesicles are long-time stable hybrid colloids and their structure is conveniently controlled by the initial mixing ratio of SiNPs and vesicles. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Synthesis and characterization of gum acacia inspired silica hybrid xerogels for mercury(II) adsorption.

    Science.gov (United States)

    Singh, Vandana; Singh, Somit Kumar

    2011-04-01

    In a sol-gel process, gum acacia inspired silica xerogels have been synthesized from tetraethylorthosilicate. Besides showing photoluminescence under ultraviolet excitation, the hybrid xerogels were very efficient in capturing mercury(II) from synthetic solution. To synthesize the optimum sample (in terms of Hg(II) uptake), different ratios of H(2)O:TEOS:EtOH were taken at fixed GA and catalyst concentrations where 4:1:1 ratio was found to be most favorable. Calcination in air further enhanced the mercury binding capacity of this sample. Optimum sample (H4) was obtained on calcination of the gel at 600°C. The hybrids have been structurally characterized using Infrared spectroscopy, X-ray diffraction, scanning electron microscopy, thermo gravimetric analysis, photoluminescence spectroscopy and Brunauer-Emmett-Teller analysis. In a preliminary batch adsorption experiment, H4 was evaluated to be highly efficient in the removal Hg(II) from synthetic aqueous solution.

  2. Synthesis of organic-inorganic hybrid sols with nano silica particles and organoalkoxysilanes for transparent and high-thermal-resistance coating films using sol-gel reaction.

    Science.gov (United States)

    Na, Moonkyong; Park, Hoyyul; Ahn, Myeongsang; Lee, Hyeonhwa; Chung, Ildoo

    2010-10-01

    Organic-inorganic hybrid sols were synthesized from nano silica particles dispersed in water and from organoalkoxysilanes, using the sol-gel reaction. This work focuses on the effects of the three multifunctional organoalkoxysilanes dimethyldimethoxysilane (DMDMS), methyltrimethoxysilane (MTMS), and tetramethoxysilane (TMOS) to form a transparent and high-thermal-resistance coating film. The stability of the hybrid sol was evaluated as a function of the reaction time for 10 d through the variation of the viscosity. The viscosity of the silica/DMDMS and silica/MTMS sol was slightly increased for 10 d. The multifunctional organoalkoxysilanes formed dense silica networks through hydrolysis and condensation reaction, which enhanced the thermal resistance of the coating films. No thermal degradation of the silica/DMDMS sample occurred up to 600 degrees C, and none of the silica/MTMS and silica/TMOS samples occurred either up to 700 degrees C. The organic-inorganic hybrid sols were coated on the glass substrate using a spin-coating procedure. The organic-inorganic hybrid sols formed flat coating films without cracks. The transmittance of the hybrid sol coating films using MTMS and DMDMS was shown to be over 90%. The transmittance of the silica/TMOS sol coating film reacted for 10 d abruptly decreased due to faster gelation. The silica/DMDMS and silica/MTMS hybrid sols formed smooth coating films while the surface roughness of the silica/TMOS coating film markedly increased when the hybrid sol reacted for 10 d. The increase of the surface roughness of the silica/TMOS coating film can be attributed to the degradation of the stability of the hybrid sol and to the loss of transmittance of the coating film. It was confirmed in this study that the use of organic-inorganic hybrid sol can yield transparent and high-thermal-resistance coating films.

  3. Nanostructured Silica/Gold-Cellulose-Bonded Amino-POSS Hybrid Composite via Sol-Gel Process and Its Properties

    Science.gov (United States)

    Ramesh, Sivalingam; Kim, Heung Soo; Lee, Young-June; Hong, Gwang-Wook; Kim, Joo-Hyung

    2017-06-01

    It is demonstrated in this paper that silica nanoparticles coated with core/shell gold provide efficient thermal, optical, and morphological properties with respect to the cellulose-polyhedral oligomeric silsesquioxanes (POSS) hybrid system. The one-step synthesis of a silica/gold nanocomposite is achieved with a simultaneous hydrolysis and reduction of gold chloride in the presence of formic acid, and the trimethoxysilane group acts as a silica precursor. The focus here comprises the synthesis of cellulose-POSS and silica/gold hybrid nanocomposites using the following two methods: (1) an in situ sol-gel process and (2) a polyvinyl alcohol/tetrakis (hydroxymethyl)phosphonium chloride process. Accordingly, the silica/gold core/shell nanoparticles are synthesized. The growth and attachment of the gold nanoparticles onto the functionalized surface of the silica at the nanometer scale is achieved via both the sol-gel and the tetrakis (hydroxymethyl) phosphonium chloride processes. The cellulose-POSS-silica/gold nanocomposites are characterized according to Fourier transformed infrared spectroscopy, Raman, X-ray diffraction, UV, photoluminescence, SEM, energy-dispersive X-ray spectroscopy, TEM, thermogravimetric, and Brunauer-Emmett-Teller analyses.

  4. Development and characterization of hybrid materials based on biodegradable PLA matrix, microcrystalline cellulose and organophilic silica

    Directory of Open Access Journals (Sweden)

    Fernanda Abbate dos Santos

    2014-10-01

    Full Text Available The goal of this work was to investigate the production and properties of hybrid materials based on poly(lactic acid (PLA, employing microcrystalline cellulose (MCC and organophilic silica (R972 as fillers. The composites were obtained by solution casting to form films. Each nanoparticle was incorporated at 3 wt. %, relative to the polymer matrix. In this experiment, four films were obtained (PLA, PLA/MCC, PLA/R972 and PLA/MCC/R972. The films properties were evaluated by X-ray diffractometry, nuclear magnetic resonance, Fourier transform infrared spectroscopy and mechanical properties. The results showed that each nanoparticle, added individually or both combined, had different effect on the final properties of the films. Microcrystalline cellulose can act as nucleating agent for the crystallization of PLA. Silica promoted an increase in rigidity, due to the strong intermolecular forces, while MCC addition promoted an increase in the molecular mobility of the polymeric chains. The PLA/MCC/R972 film showed the highest crystallinity degree and tensile modulus. This film presented a T1H value between both values found for PLA/MCC and PLA/R972 films. The results indicated that silica R972 could promote a decrease of the surface tension between PLA and cellulose.

  5. Novel bimodal porous N-(2-aminoethyl)-3-aminopropyltrimethoxysilane-silica monolithic capillary microextraction and its application to the fractionation of aluminum in rainwater and fruit juice by electrothermal vaporization inductively coupled plasma mass spectrometry

    Science.gov (United States)

    Zheng, Fei; Hu, Bin

    2008-01-01

    A novel bimodal porous N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AAPTS)-silica monolithic capillary was prepared by sol-gel technology, and used as capillary microextraction (CME) column for aluminum fractionation by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV)-ICP-MS with the use of polytetrafluoroethylene (PTFE) slurry as fluorinating agent. The extraction behaviors of different Al species were studied and it was found that in the pH range of 4-7, labile monomeric Al (free Al 3+, Al-OH and Al-F) could be retained quantitatively on the monolithic capillary, while non-labile monomeric Al (Al-Cit and Al-EDTA) passed through the capillary directly. The labile monomeric Al retained on monolithic capillary was eluted with 10 μL 1 mol L - 1 HCl and the elution was introduced into the ETV for fluorination assisted ETV-ICP-MS determination. The total monomeric Al fraction was also determined by AAPTS-silica monolithic CME-fluorination-assisted electrothermal vaporization (FETV)-ICP-MS after the sample solution was adjusted to pH 8.8. Non-labile monomeric Al was obtained by subtracting labile monomeric Al from the total monomeric Al. Under the optimized conditions, the relative standard deviation (R.S.D) was 6.2% ( C = 1 μg L - 1 , n = 7; sample volume, 5 mL), and the limit of detection was 1.6 ng L - 1 for Al with an enrichment factor of 436 fold and a sampling frequency of 9 h - 1 . The prepared AAPTS-silica monolithic capillary showed an excellent pH tolerance and solvent stability and could be used for more than 250 times without decreasing adsorption efficiency. The developed method was applied to the fraction of Al in rainwater and fruit juice, and the results demonstrated that the established system had advantages over the existing 8-hydroxyquinoline (8-HQ) chelating system for Al fractionation such as wider pH range, higher tolerance of interference and better regeneration.

  6. Dummy molecularly imprinted mesoporous silica prepared by hybrid imprinting method for solid-phase extraction of bisphenol A.

    Science.gov (United States)

    Yu, Dan; Hu, Xiaolei; Wei, Shoutai; Wang, Qiang; He, Chiyang; Liu, Shaorong

    2015-05-29

    A novel hybrid dummy imprinting strategy was developed to prepare a mesoporous silica for the solid-phase extraction (SPE) of bisphenol A (BPA). A new covalent template-monomer complex (BPAF-Si) was first synthesized with 2,2-bis(4-hydroxyphenyl)hexafluoropropane (BPAF) as the template. The imprinted silica was obtained through the gelation of BPAF-Si with tetraethoxysilane and the subsequent removal of template by thermal cleavage, and then it was characterized by FT-IR spectroscopy, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption-desorption isotherms. Results showed that the new silica had micron-level particle size and ordered mesoporous structure. The static binding test verified that the imprinted silica had much higher recognition ability for BPA than the non-imprinted silica. The imprinted silica also showed high extraction efficiencies and high enrichment factor for SPE of BPA. Using the imprinted silica, a SPE-HPLC-UV method was developed and successfully applied for detecting BPA in BPA-spiked tap water and lake water samples with a recovery of 99-105%, a RSD of 2.7-5.0% and a limit of detection (S/N=3) of 0.3ng/mL. The new imprinted silica avoided the interference of the residual template molecules and reduced the non-specific binding sites, and therefore it can be utilized as a good sorbent for SPE of BPA in environmental water samples.

  7. Independent control of adhesive and bulk properties of hybrid silica coatings on polycarbonate.

    Science.gov (United States)

    Lionti, Krystelle; Cui, Linying; Volksen, Willi; Dauskardt, Reinhold; Dubois, Geraud; Toury, Berangere

    2013-11-13

    Transparent polymers are widely used in many applications ranging from automotive windows to microelectronics packaging. However, their intrinsic characteristics, in particular their mechanical properties, are significantly degraded with exposure to different weather conditions. For instance, under humid environment or UV-irradiation, polycarbonate (PC) undergoes depolymerization, leading to the release of Bisphenol A, a molecule presumed to be a hormonal disruptor, potentially causing health problems. This is a serious concern and the new REACH (Registration, Evaluation, Authorization and Restriction of Chemical substances ) program dictates that materials releasing Bisphenol A should be removed from the market by January 1st, 2015 (2012-1442 law). Manufacturers have tried to satisfy this new regulation by depositing atop the PC a dense oxide-like protective coating that would act as a barrier layer. While high hardness, modulus, and density can be achieved by this approach, these coatings suffer from poor adhesion to the PC as evidenced by the numerous delamination events occurring under low scratch constraints. Here, we show that the combination of a N2/H2-plasma treatment of PC before depositing a hybrid organic-inorganic solution leads to a coating displaying elevated hardness, modulus, and density, along with a very high adherence to PC (> 20 J/m(2) as measured by double cantilever beam test). In this study, the sol-gel coatings were composed of hybrid O/I silica (based on organoalkoxysilanes and colloidal silica) and designed to favor covalent bonding between the hybrid network and the surface treated PC, hence increasing the contribution of the plastic deformation from the substrate. Interestingly, double-cantilever beam (DCB) tests showed that the coating's adhesion to PC was the same irrespective of the organoalkoxysilanes/colloidal silica ratio. The versatility of the sol-gel deposition techniques (dip-coating, spray-coating, etc.), together with the

  8. A bioactive coating of a silica xerogel/chitosan hybrid on titanium by a room temperature sol-gel process.

    Science.gov (United States)

    Jun, Shin-Hee; Lee, Eun-Jung; Yook, Se-Won; Kim, Hyoun-Ee; Kim, Hae-Won; Koh, Young-Hag

    2010-01-01

    A bioactive coating consisting of a silica xerogel/chitosan hybrid was applied to Ti at room temperature as a novel surface treatment for metallic implants. A crack-free thin layer (coated on Ti with a chitosan content of >30 vol.% through a sol-gel process. The coating layer became more hydrophilic with increasing silica xerogel content, as assessed by contact angle measurement. The hybrid coatings afforded excellent bone bioactivity by inducing the rapid precipitation of apatite on their surface when immersed in a simulated body fluid (SBF). Osteoblastic cells cultured on the hybrid coatings were more viable than those on a pure chitosan coating. Furthermore, the alkaline phosphate activity of the cells was significantly higher on the hybrid coatings than on a pure chitosan coating, with the highest level being achieved on the hybrid coating containing 30% chitosan. These results indicate that silica xerogel/chitosan hybrids are potentially useful as room temperature bioactive coating materials on titanium-based medical implants.

  9. Mesoporous sol-gel silica cladding for hybrid TiO2/electro-optic polymer waveguide modulators.

    Science.gov (United States)

    Enami, Yasufumi; Kayaba, Yasuhisa; Luo, Jingdong; Jen, Alex K-Y

    2014-06-30

    We report the efficient poling of an electro-optic (EO) polymer in a hybrid TiO(2)/electro-optic polymer multilayer waveguide modulator on mesoporous sol-gel silica cladding. The mesoporous sol-gel silica has nanometer-sized pores and a low refractive index of 1.24, which improves mode confinement in the 400-nm-thick EO polymer film in the modulators and prevents optical absorption from the lower Au electrode, thereby resulting in a lower half-wave voltage of the modulators. The half-wave voltage (Vπ) of the hybrid modulator fabricated on the mesoporous sol-gel silica cladding is 6.0 V for an electrode length (Le) of 5 mm at a wavelength of 1550 nm (VπLe product of 3.0 V·cm) using a low-index guest-host EO polymer (in-device EO coefficient of 75 pm/V).

  10. Hybrid carbon nanoparticles modified core-shell silica: a high efficiency carbon-based phase for hydrophilic interaction liquid chromatography.

    Science.gov (United States)

    Ibrahim, Mohammed E A; Wahab, M Farooq; Lucy, Charles A

    2014-04-11

    Hydrophilic interaction liquid chromatography (HILIC) is a fast growing separation technique for hydrophilic and polar analytes. In this work, we combine the unique selectivity of carbon surfaces with the high efficiency of core-shell silica. First, 5 μm core-shell silica is electrostatically coated with 105 nm cationic latex bearing quaternary ammonium groups. Then 50 nm anionic carbon nanoparticles are anchored onto the surface of the latex coated core-shell silica particles to produce a hybrid carbon-silica phase. The hybrid phase shows different selectivity than ten previously classified HILIC column chemistries and 36 stationary phases. The hybrid HILIC phase has shape selectivity for positional isomeric pairs (phthalic/isophthalic and 1-naphthoic/2-naphthoic acids). Fast and high efficiency HILIC separations of biologically important carboxylates, phenols and pharmaceuticals are reported with efficiencies up to 85,000 plates m(-1). Reduced plate height of 1.9 (95,000 plates m(-1)) can be achieved. The hybrid phase is stable for at least 3 months of usage and storage under typical HILIC eluents.

  11. A novel hybrid material: an inorganic silica aerogel core encapsulated with a tunable organic alginate aerogel layer

    OpenAIRE

    Ülker, Zeynep; Erkey, Can

    2014-01-01

    A novel layered material consisting of a silica aerogel core encapsulated by an alginate aerogel layer was developed. The components of the hybrid aerogel had the high surface area and high porosity of pure aerogels which should lead to development of new layered systems for a wide variety of applications.

  12. Preparation and characterization of hybrid Nafion/silica and Nafion/silica/PTA membranes for redox flow batteries

    Energy Technology Data Exchange (ETDEWEB)

    Glibin, V.; Pupkevich, V.; Svirko, L.; Karamanev, D. [Western Ontario Univ., London, ON (Canada). Dept. of Biochemical and Chemical Engineering

    2008-07-01

    Redox flow batteries are both efficient and cost-effective. However, the long-term stability of most ion-exchange membranes is limited as a result of the high oxidation rates of ions with high redox potentials. A method of synthesizing multi-component Nafion-silica and Nafion-silica-PTA membranes was presented in this study, which also investigated the electrochemical and ion transport properties of the membranes. Membranes were cast from dimethylformamide (DMFA) solution. The iron ion diffusion kinetics of the Nafion-silica and Nafion-silica PTA membranes were studied by dialysis. Results of the investigation demonstrated that the introduction of silica and phosphotungstic acid (PTA) into the Nafion membrane composition resulted in a significant decrease of ion transfer through the membrane. The addition of PTA also increased membrane permeability to ferric ions. The low iron diffusion coefficient and high ionic conductivity of the Nafion-silica membrane makes it a promising material for use in redox flow batteries. 4 refs., 1 tab., 1 fig.

  13. The evaluation of physical properties and in vitro cell behavior of PHB/PCL/sol-gel derived silica hybrid scaffolds and PHB/PCL/fumed silica composite scaffolds.

    Science.gov (United States)

    Ding, Yaping; Yao, Qingqing; Li, Wei; Schubert, Dirk W; Boccaccini, Aldo R; Roether, Judith A

    2015-12-01

    PHB/PCL/sol-gel derived silica hybrid scaffolds (P5S1S) and PHB/PCL/fumed silica composite scaffolds (P5S1N) with a 5:1 organic/inorganic ratio were fabricated through a combination of electrospinning and sol-gel methods and dispersion electrospinning, respectively. In contrast to the silica nanoparticle aggregates appearing on the fiber surface of P5S1N, smooth and uniform fibers were obtained for P5S1S. The fiber diameter distribution, tensile strength, thermal gravimetric analysis (TGA), and cellular behavior of both types of scaffolds were characterized and studied. The tensile strength results and TGA indicated that the interfacial interaction between the organic and the inorganic phase was enhanced in P5S1S over the nanocomposite scaffolds, and cells exhibited significantly higher alkaline phosphate activity (ALP) for P5S1S, which makes P5S1S hybrid scaffolds candidate materials for bone tissue engineering applications.

  14. Polymer-silica hybrids for separation of CO2 and catalysis of organic reactions

    Science.gov (United States)

    Silva Mojica, Ernesto

    spectroscopic investigation of the interactions of CO 2 with amine molecules under simulated CO2 capture conditions. Industrial CO2 capture processes involve fluidization and require degradation-resistant sorbents in the form of pellets. Agglomeration of silica-based CO2 capture sorbents involved the formulation of a polymer binder solution and the design of a scalable pelletization process. The characterization of these pellets revealed the formation of a CO 2-permeable polymer-silica network, which is resistant to attrition, and exhibits similar CO2 capture and degradation performance as the non-pelletized sorbents. The performance of these sorbents and pellets was tested in lab-scale and bench-scale adsorption units, using in-house fabricated fixed-bed and fluidized-bed reactors. A compartmental modeling technique was used to simulate the CO2 adsorption process and to elucidate the kinetic and thermodynamic parameters that impact the commercial viability of emerging CO2 capture technologies. The fundamental concepts and experimental techniques developed for the preparation of CO2 capture sorbents served as a basis for fabricating amine-functionalized polymer-silica hybrids for applications in catalysis of organic reactions. (i) Basic catalysts for carbon-carbon addition reactions were prepared by immobilization of amine molecules on silica supports. The activity of these catalysts and the mechanisms of base-catalyzed organic condensation reactions were investigated by an in-situ FTIR micro-scale reactor. (ii) Particle-loaded PVA composite membranes were selected for immobilization of glucose oxidase (GOx). GOx was immobilized by adsorption at pH values between 3.5 and 7.1. The results showed that adsorption was primarily achieved via hydrophobic interactions, and that PVA membranes loaded with amine-functionalized particles could help retain the activity of immobilized GOx by providing a proper hydrophilic/hydrophobic balance to the immobilized enzymes micro-environment.

  15. Approaches to nanostructure control and functionalizations of polymer@silica hybrid nanograss generated by biomimetic silica mineralization on a self-assembled polyamine layer

    Directory of Open Access Journals (Sweden)

    Jian-Jun Yuan

    2011-11-01

    Full Text Available We report the rational control of the nanostructure and surface morphology of a polyamine@silica nanoribbon-based hybrid nanograss film, which was generated by performing a biomimetic silica mineralization reaction on a nanostructured linear polyethyleneimine (LPEI layer preorganized on the inner wall of a glass tube. We found that the film thickness, size and density of the nanoribbons and the aggregation/orientation of the nanoribbons in the film were facile to tune by simple adjustment of the biomimetic silicification conditions and LPEI self-assembly on the substrate. Our LPEI-mediated nanograss process allows the facile and programmable generation of a wide range of nanostructures and surface morphologies without the need for complex molecular design or tedious techniques. This ribbon-based nanograss has characteristics of a LPEI@silica hybrid structure, suggesting that LPEI, as a polymeric secondary amine, is available for subsequent chemical reaction. This feature was exploited to functionalize the nanograss film with three representative species, namely porphyrin, Au nanoparticles and titania. Of particular note, the novel silica@titania composite nanograss surface demonstrated the ability to convert its wetting behavior between the extreme states (superhydrophobic–superhydrophilic by surface hydrophobic treatment and UV irradiation. The anatase titania component in the nanograss film acts as a highly efficient photocatalyst for the decomposition of the low-surface-energy organic components attached to the nanosurface. The ease with which the nanostructure can be controlled and facilely functionalized makes our nanograss potentially important for device-based application in microfluidic, microreactor and biomedical fields.

  16. Organoclay hybrid materials as precursors of porous ZnO/silica-clay heterostructures for photocatalytic applications

    Directory of Open Access Journals (Sweden)

    Marwa Akkari

    2016-12-01

    Full Text Available In this study, ZnO/SiO2-clay heterostructures were successfully synthesized by a facile two-step process applied to two types of clays: montmorillonite layered silicate and sepiolite microfibrous clay mineral. In the first step, intermediate silica–organoclay hybrid heterostructures were prepared following a colloidal route based on the controlled hydrolysis of tetramethoxysilane in the presence of the starting organoclay. Later on, pre-formed ZnO nanoparticles (NP dispersed in 2-propanol were incorporated under ultrasound irradiation to the silica–organoclay hybrid heterostructures dispersed in 2-propanol, and finally, the resulting solids were calcinated to eliminate the organic matter and to produce ZnO nanoparticles (NP homogeneously assembled to the clay–SiO2 framework. In the case of montmorillonite the resulting materials were identified as delaminated clays of ZnO/SiO2-clay composition, whereas for sepiolite, the resulting heterostructure is constituted by the assembling of ZnO NP to the sepiolite–silica substrate only affecting the external surface of the clay. The structural and morphological features of the prepared heterostructures were characterized by diverse physico-chemical techniques (such as XRD, FTIR, TEM, FE-SEM. The efficiency of these new porous ZnO/SiO2-clay heterostructures as potential photocatalysts in the degradation of organic dyes and the removal of pharmaceutical drugs in water solution was tested using methylene blue and ibuprofen compounds, respectively, as model of pollutants.

  17. Design and synthesis of temperature-responsive polymer/silica hybrid nanoparticles and application to thermally controlled cellular uptake.

    Science.gov (United States)

    Hiruta, Yuki; Nemoto, Ryo; Kanazawa, Hideko

    2017-05-01

    This study reports the development of temperature-responsive polymer/silica hybrid nanoparticles and their application to temperature-dependent intracellular uptake of hydrophobic encapsulated fluorescence molecules. Amphiphilic diblock copolymer comprising a temperature-responsive segment, poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) [P(NIPAAm-co-DMAAm)] and a trimethyoxysilyl-containing hydrophobic segment was synthesized (PBM-b-ND); this amphiphilic diblock copolymer self-assembled in an aqueous solution, and temperature-responsive polymer/silica hybrid fluorescence nanoparticles were fabricated via a base-catalyzed sol-gel process. The fluorescence probe rhodamine DHPE or boron dipyrromethene derivative was encapsulated into the polymer core with a silica network in a stable manner. Other types of polymer/silica hybrid fluorescence nanoparticles were also developed using either homo-PNIPAAm (PBM-b-N) or homo-PDMAAm (PBM-b-D) segments, instead of P(NIPAAm-co-DMAAm). While PBM-b-D did not exhibit a temperature-dependent phase transition (hydrophilic characteristic), PBM-b-N and PBM-b-ND exhibited temperature-dependent phase transition (hydrophilic/hydrophobic) at 32°C and 38°C, respectively. The cellular uptake of PBM-b-N was clearly observed at both 37°C and 42°C, while the cellular uptake of PBM-b-D was minimal at these temperatures. On the other hand, significant enhancement in the intracellular uptake of PBM-b-ND was observed at 42°C, compared to its uptake at a lower temperature of 37°C. These results indicated that temperature-responsive polymer/silica hybrid nanoparticle, PBM-b-ND demonstrate potential for applications in theranostics with cancer therapy via the combination of local drug delivery and local hyperthermia, as well as for monitoring treatment effectiveness with fluorescence imaging. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Substrate integrated Lead-Carbon hybrid ultracapacitor with flooded, absorbent glass mat and silica-gel electrolyte configurations

    OpenAIRE

    Banerjee, A.; Ravikumar, MK; Jalajakshi, A; Kumar, Suresh P; Gaffoor, SA; Shukla, AK

    2012-01-01

    Lead-Carbon hybrid ultracapacitors (Pb-C HUCs) with flooded, absorbent-glass-mat (AGM) and silica-gel sulphuric acid electrolyte configurations are developed and performance tested. Pb-C HUCs comprise substrate-integrated PbO2 (SI-PbO2) as positive electrodes and high surface-area carbon with graphite-sheet substrate as negative electrodes. The electrode and silica-gel electrolyte materials are characterized by XRD, XPS, SEM, TEM, Rheometry, BET surface area, and FTIR spectroscopy in conjunct...

  19. Enhancement of Hybrid SPEEK Based Polymer–Cyclodextrin-Silica Inorganic Membrane for Direct Methanol Fuel Cell Application

    Directory of Open Access Journals (Sweden)

    Tutuk Djoko Kusworo

    2017-06-01

      Keywords: Direct Methanol Fuel Cell, Poly(ether ether ketone, cyclodextrin-silica, sulfonation, ionic conductivity. Article History: Received January 18th 2017; Received in revised form April 21st 2017; Accepted June 22nd 2017; Available online How to Cite This Article: Kusworo, T.D., Hakim, M.F. and Hadiyanto, H. (2017 Enhancement of Hybrid SPEEK Based Polymer–Cyclodextrin-Silica Inorganic Membrane for Direct Methanol Fuel Cell Application. International Journal of Renewable Energy Development, 6(2, 165-170. https://doi.org/10.14710/ijred.6.2.165-170

  20. Preparation and Characterization of Gold Nanoparticle-Modified Silica Monolith for Capillary Electrochromatography%金纳米粒子修饰毛细管硅胶整体柱的制备及其电色谱性能研究

    Institute of Scientific and Technical Information of China (English)

    叶芳贵; 陆俊宇; 王圆; 张爱珠; 田建袅; 赵书林

    2011-01-01

    通过毛细管硅胶整体柱表面修饰十八烷基硫醇金纳米粒子,制备了一种新型毛细管电色谱固定相.制备金纳米粒子修饰整体柱时,采用溶胶-凝胶法制备毛细管硅胶整体柱,并在其表面化学修饰3-巯基丙基三甲氧基硅烷;通过巯基基团固载金纳米粒子于整体柱上,再共价键合十八烷基硫醇于金纳米粒子表面.以甲苯为探针,对理论塔板高度与流动相线速度之间的关系进行了考察,其最小理论塔板高度约为7.8 μm.考察了操作条件如流动相中的有机改性剂和缓冲溶液pH值对金纳米粒子修饰毛细管整体柱电渗流的影响,并与相应的毛细管硅胶整体柱(Silica)进行比较.以烷基苯同系物为模型化合物,评价了Silica、巯基 (Silica-SH)和十八烷基(Silica-GNPs-C18) 3种整体柱电色谱性能;还考察了烷基苯同系物在Silica-GNPs-C18上的保留行为.结果表明,其保留机理是基于典型的反相作用.另外,在甲醇含量为15%的流动相条件下,Silica-GNPs-C18还可实现4 种极性苯酚类物质的基线分离.%A novel silica monolithic stationary phase functionalized with octadecanethiol gold nanoparticles was prepared for capillary electrochromatography (CEC). The bare monolithic silica column was prepared by a sol-gel process and has been chemically modified with 3-mercaptopropyl-trimethoxysilane, followed by immobilization of gold nanoparticles and modification by octadecanethiol. The relationship between plot of plate height and the linear velocity on gold nanoparticle-modified silica monolith was investigated, and a minimum plate height of about 7.8 μm for toluene was obtained.The electroosmotic flow characteristics of the gold nanoparticle-modified silica monolith and bare silica monolith (Silica) were studied by varying the percentage of organic modifier in buffer and buffer pH.To evaluate the column performance, hydrophobic alkylbenzenes as model compounds were tested on the

  1. Investigation of Mechanical and Electrical Properties of Hybrid Composites Reinforced with Carbon Nanotubes and Micrometer-Sized Silica Particles

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Yun; You, Byeong Il; Ahn, Ji Ho; Lee, Gyo Woo [Chonbuk Nat’l Univ., Junju (Korea, Republic of)

    2016-12-15

    In this study, to enhance the electrical insulation of composite specimens in addition to the improved mechanical properties, the epoxy composite were reinforced with carbon nanotubes and silica particles. Tensile strength, Young's modulus, dynamic mechanical behavior, and electrical resistivity of the specimens were measured with varied contents of the two fillers. The mechanical and electrical properties were discussed, and the experimental results related to the mechanical properties of the specimens were compared with those from several micromechanics models. The hybrid composites specimens with 0.6 wt% of carbon nanotubes and 50 wt% of silica particles showed improved mechanical properties, with increase in tensile strength and Young's modulus up to 11% and 35%, respectively, with respect to those of the baseline specimen. The electrical conductivity of the composite specimens with carbon nanotubes filler also improved. Further, the electrical insulation of the hybrid composites specimens with the two fillers improved in addition to the improvement in mechanical properties.

  2. Controlled growth of silica-titania hybrid functional nanoparticles through a multistep microfluidic approach.

    Science.gov (United States)

    Shiba, K; Sugiyama, T; Takei, T; Yoshikawa, G

    2015-11-11

    Silica/titania-based functional nanoparticles were prepared through controlled nucleation of titania and subsequent encapsulation by silica through a multistep microfluidic approach, which was successfully applied to obtaining aminopropyl-functionalized silica/titania nanoparticles for a highly sensitive humidity sensor.

  3. Separation and Analysis of Organic Acids in Food by Capillary Silica Monolithic Column%毛细管硅胶整体柱分离分析食品中有机酸

    Institute of Scientific and Technical Information of China (English)

    高文惠; 杨桂君; 贾英民

    2012-01-01

    A capillary electrochromatographic method for the separation and analysis of organic acids in food was proposed using a capillary silica monolithic column.Optimization of experimental parameters that influence separation efficiency was carried out.A capillary silica monolithic C18 column was prepared in our lab for the separation of organic acids using a mobile phase(pH 5.2) consisting of 150 mmol/L sodium dihydrogen phosphate-60 mmol/L borax buffer solution with a final concentration of 5:2 in the mixture and 0.5 mmol/L cetyl trimethyl ammonium bromide.Other experimental conditions were as follows: voltage-6 kV;injection time 10 s;column temperature 25 ℃;and detection wavelength 200 nm.Results showed that the linear range was 10–1000 μg/mL for oxalic acid and fumaric acid,20–500 μg/mL for succinic acid,15–1000 μg/mL for tartaric acid and citric acid.The average recovery rates for the organic acids were between 89.8% and 101.1%,with a relative standard deviation(RSD) less than or equal to 6.23%(n = 5).The detection limits of the proposed methods were between 3.0 and 7.5 μg/mL.In conclusion,capillary silica monolithic column is inexpensive,stable to heat and organic solvents,and repeatedly usable.Capillary electrochromatography with capillary silica monolithic column allows simple,rapid and effective separation and analysis of organic acids in food.%建立应用毛细管硅胶整体柱采用毛细管电色谱法分离分析食品中有机酸的方法。对影响毛细管电色谱分离效率的条件进行优化,色谱柱为本实验室制作的毛细管硅胶整体C18柱(100μm×40cm)、电压-6kV、进样时间10s、紫外检测波长200nm,流动相为150mmol/L磷酸二氢钠-60mmol/L硼砂缓冲溶液(浓度比为5:2)和0.5mmol/L十六烷基三甲基溴化铵,pH7.5、25℃。结果表明:草酸和富马酸的线性范围为10~1000μg/mL,丁二酸线性范围20~500μg/mL,酒石酸和柠檬酸的线性范围为15~1000μg

  4. Ceria nanoparticles vis-à-vis cerium nitrate as corrosion inhibitors for silica-alumina hybrid sol-gel coating

    Science.gov (United States)

    Lakshmi, R. V.; Aruna, S. T.; Sampath, S.

    2017-01-01

    The present work provides a comparative study on the corrosion protection efficiency of defect free sol-gel hybrid coating containing ceria nanoparticles and cerium nitrate ions as corrosion inhibitors. Less explored organically modified alumina-silica hybrid sol-gel coatings are synthesized from 3-glycidoxypropyltrimethoxysilane and aluminium-tri-sec-butoxide. The microemulsion derived nanoparticles and the hybrid coatings are characterized and compared with coatings containing cerium nitrate. Corrosion inhibiting capability is assessed using electrochemical impedance spectroscopy. Scanning Kelvin probe measurements are also conducted on the coatings for identifying the apparent corrosion prone regions. Detailed X-ray photoelectron spectroscopy (XPS) analysis is carried out to comprehend the bonding and corrosion protection rendered by the hybrid coatings.

  5. Analysis of drugs in plasma samples from schizophrenic patients by column-switching liquid chromatography-tandem mass spectrometry with organic-inorganic hybrid cyanopropyl monolithic column.

    Science.gov (United States)

    Domingues, Diego Soares; Souza, Israel Donizeti de; Queiroz, Maria Eugênia Costa

    2015-07-01

    This study reports on the development of a rapid, selective, and sensitive column-switching liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to analyze sixteen drugs (antidepressants, anticonvulsants, anxiolytics, and antipsychotics) in plasma samples from schizophrenic patients. The developed organic-inorganic hybrid monolithic column with cyanopropyl groups was used for the first dimension of the column-switching arrangement. This arrangement enabled online pre-concentration of the drugs (monolithic column) and their subsequent analytical separation on an XSelect SCH C18 column. The drugs were detected on a triple quadrupole tandem mass spectrometer (multiple reactions monitoring mode) with an electrospray ionization source in the positive ion mode. The developed method afforded adequate linearity for the sixteen target drugs; the coefficients of determination (R(2)) lay above 0.9932, the interassay precision had coefficients of variation lower than 6.5%, and the relative standard error values of the accuracy ranged from -14.0 to 11.8%. The lower limits of quantification in plasma samples ranged from 63 to 1250pgmL(-1). The developed method successfully analyzed the target drugs in plasma samples from schizophrenic patients for therapeutic drug monitoring (TDM).

  6. Facile "one-pot" synthesis of poly(methacrylic acid)-based hybrid monolith via thiol-ene click reaction for hydrophilic interaction chromatography.

    Science.gov (United States)

    Lv, Xumei; Tan, Wangming; Chen, Ye; Chen, Yingzhuang; Ma, Ming; Chen, Bo; Yao, Shouzhuo

    2016-07-08

    A novel sol-gel "one-pot" approach in tandem with a radical-mediated thiol-ene reaction for the synthesis of a methacrylic acid-based hybrid monolith was developed. The polymerization monomers, tetramethoxysilane (TMOS) and 3-mercaptopropyl trimethoxysilane (MPTS), were hydrolyzed in high-concentration methacrylic acid solution that also served as a hydrophilic functional monomer. The resulting solution was then mixed with initiator (2, 2'-azobis (2-methylpropionamide) dihydrochloride) and porogen (urea, polyethylene glycol 20,000) in a capillary column and polymerized in water bath. The column had a uniform porous structure and a good permeability. The evaluation of the monolith was performed by separation of small molecules including nucleosides, phenols, amides, bases and Triton X-100. The calibration curves for uridine, inosine, adenosine and cytidine were determined. All the calibration curves exhibited good linear regressions (R(2)≥0.995) within the test ranges of 0.5-40μg/mL for four nucleosides. Additionaliy, atypical hydrophilic mechanism was proved by elution order from low to high according to polarity retention time increased with increases in the content of the organic solvent in the mobile phase. Further studies indicated that hydrogen bond and electrostatic interactions existed between the polar analytes and the stationary phase. This was the mechanism of retention. The excellent separation of the BSA digest showed good hydrophility of the column and indicated the potential in separation of complex biological samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Precise size control over ultrafine rutile titania nanocrystallites in hierarchical nanotubular silica/titania hybrids with efficient photocatalytic activity.

    Science.gov (United States)

    Gu, Yuanqing; Huang, Jianguo

    2013-08-12

    Hierarchical-structured nanotubular silica/titania hybrids incorporated with particle-size-controllable ultrafine rutile titania nanocrystallites were realized by deposition of ultrathin titania sandwiched silica gel films onto each nanofiber of natural cellulose substances (e.g., common commercial filter paper) and subsequent flame burning in air. The rapid flame burning transforms the initially amorphous titania into rutile phase titania, and the silica gel films suppress the crystallite growth of rutile titania, thereby achieving nano-precise size regulation of ultrafine rutile titania nanocrystallites densely embedded in the silica films of the nanotubes. The average diameters of these nanocrystallites are adjustable in a range of approximately 3.3-16.0 nm by a crystallite size increment rate of about 2.4 nm per titania deposition cycle. The silica films transfer the electrons activated by crystalline titania and generate catalytic reactive species at the outer surface. The size-tuned ultrafine rutile titania nanocrystallites distributed in the unique hierarchical networks significantly improve the photocatalytic performance of the rutile phase titania, thereby enabling a highly efficient photocatalytic degradation of the methylene blue dye under ultraviolet light irradiation, which is even superior to the pure anatase-titania-based materials. The facile stepwise size control of the rutile titania crystallites described here opens an effective pathway for the design and preparation of fine-nanostructured rutile phase titania materials to explore potential applications.

  8. Lyophilized silica lipid hybrid (SLH) carriers for poorly water-soluble drugs: physicochemical and in vitro pharmaceutical investigations.

    Science.gov (United States)

    Yasmin, Rokhsana; Tan, Angel; Bremmell, Kristen E; Prestidge, Clive A

    2014-09-01

    Lyophilization was investigated to produce a powdery silica-lipid hybrid (SLH) carrier for oral delivery of poorly water-soluble drugs. The silica to lipid ratio, incorporation of cryoprotectant, and lipid loading level were investigated as performance indicators for lyophilized SLH carriers. Celecoxib, a nonsteroidal anti-inflammatory drug, was used as the model poorly soluble moiety to attain desirable physicochemical and in vitro drug solubilization properties. Scanning electron microscopy and confocal fluorescence imaging verified a nanoporous, homogenous internal matrix structures of the lyophilized SLH particles, prepared from submicron triglyceride emulsions and stabilized by porous silica nanoparticles (Aerosil 380), similar to spray-dried SLH. 20-50 wt % of silica in the formulation have shown to produce nonoily SLH agglomerates with complete lipid encapsulation. The incorporation of a cryoprotectant prevented irreversible aggregation of the silica-stabilized droplets during lyophilization, thereby readily redispersing in water to form micrometre-sized particles (drug solubilization than the pure drug under nondigesting and digesting conditions, respectively. The feasibility of lyophilization for producing nanostructured SLH formulations with desirable lipid loading and drug solubilization properties for enhanced oral delivery of poorly water-soluble therapeutics is confirmed. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  9. Characterization of carbon silica hybrid fillers obtained by pyrolysis of waste green tires by the STEM–EDX method

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hartomy, Omar A. [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Department of Physics, Faculty of Science, University of Tabuk, Tabuk 71491 (Saudi Arabia); Al-Ghamdi, Ahmed A. [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Al Said, Said A. Farha [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Department of Physics, Faculty of Science, University of Tabuk, Tabuk 71491 (Saudi Arabia); Dishovsky, Nikolay, E-mail: dishov@uctm.edu [Department of Polymer Engineering, University of Chemical Technology and Metallurgy, 8 Kl. Ohridski Blvd., 1756 Sofia (Bulgaria); Ward, Michael B. [LEMAS, Institute for Materials Research, SPEME, University of Leeds, LS2 9JT (United Kingdom); Mihaylov, Mihail; Ivanov, Milcho [Department of Polymer Engineering, University of Chemical Technology and Metallurgy, 8 Kl. Ohridski Blvd., 1756 Sofia (Bulgaria)

    2015-03-15

    Dual phase carbon–silica hybrid fillers obtained by pyrolysis-cum-water vapor of waste green tires have been characterized by energy dispersive X-ray spectroscopy in a scanning transmission electron microscope, silicate analysis, weight analysis, atomic absorption spectroscopy and by inductively coupled plasma–optical emission spectroscopy. The results achieved have shown that the location and distribution of the phases in the carbon silica hybrid fillers as well as their most essential characteristics are influenced by the pyrolysis conditions. The carbon phase of the filler thus obtained is located predominantly in the space among silica aggregates which have already been existing while it has been formed by elastomer destruction in the course of pyrolysis. The presence of ZnS also has been found in the hybrid fillers investigated. - Highlights: • Dual phase fillers obtained by pyrolysis of waste green tires have been characterized. • The STEM–EDX method was used for characterization. • The phase distributions in the fillers are influenced by the pyrolysis conditions.

  10. Synthesis and electrical characterization of low-temperature thermal-cured epoxy resin/functionalized silica hybrid-thin films for application as gate dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Na, Moonkyong, E-mail: nmk@keri.re.kr [HVDC Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of); System on Chip Chemical Process Research Center, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 790-784 (Korea, Republic of); Kang, Young Taec [Creative and Fundamental Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of); Department of Polymer Science and Engineering, Pusan National University, Busan, 609-735 (Korea, Republic of); Kim, Sang Cheol [HVDC Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of); Kim, Eun Dong [Creative and Fundamental Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of)

    2013-07-31

    Thermal-cured hybrid materials were synthesized from homogenous hybrid sols of epoxy resins and organoalkoxysilane-functionalized silica. The chemical structures of raw materials and obtained hybrid materials were characterized using Fourier transform infrared spectroscopy. The thermal resistance of the hybrids was enhanced by hybridization. The interaction between epoxy matrix and the silica particles, which caused hydrogen bonding and van der Waals force was strengthened by organoalkoxysilane. The degradation temperature of the hybrids was improved by approximately 30 °C over that of the parent epoxy material. The hybrid materials were formed into uniformly coated thin films of about 50 nm-thick using a spin coater. An optimum mixing ratio was used to form smooth-surfaced hybrid films. The electrical property of the hybrid film was characterized, and the leakage current was found to be well below 10{sup −6} A cm{sup −2}. - Highlights: • Preparation of thermal-curable hybrid materials using epoxy resin and silica. • The thermal stability was enhanced through hybridization. • The insulation property of hybrid film was investigated as gate dielectrics.

  11. Monolithic spectrometer

    Science.gov (United States)

    Rajic, Slobodan; Egert, Charles M.; Kahl, William K.; Snyder, Jr., William B.; Evans, III, Boyd M.; Marlar, Troy A.; Cunningham, Joseph P.

    1998-01-01

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays.

  12. A new approach to fabricate bioactive silica binary and ternary hybrid microspheres.

    Science.gov (United States)

    Angelopoulou, A; Efthimiadou, E K; Kordas, G

    2015-08-01

    Bioactive microspheres represent an extremely developing field in biomedical applications, such as bone tissue engineering and bone pathologies (metabolic bone disease, trauma or bone cancer). Their innate osteogenic properties have turned them to biomaterials with improved added value. The aim of this study was to prepare binary and ternary hybrid silica microspheres with enhanced bioactive properties according to our previous synthetic procedure. In brief, the synthetic approach based on the emulsifier free-emulsion polymerization method, by which polystyrene (PS) microspheres were produced and used as core template for the sol-gel coating method. During the coating reaction an inorganic shell was fabricated by silane and phosphate precursors (tetraethoxysilane, trimethylphosphate). The final microspheres were treated by different catalyst concentrations, during the coating process, which resulted in the formation of diffused voids (a porous-like structure). The in vitro bioactivity of the resultant microspheres was studied by treatment in simulated body fluids (SBF). The bioassay evaluation indicates the deposition of a bone-like apatite layer on microspheres' surface with enhanced bioresorbability, which verifies their bioactivity and permits their application in the treatment of bone pathologies.

  13. The 650-nm variable optical attenuator based on polymer/silica hybrid waveguide

    Science.gov (United States)

    Yue-Yang, Yu; Xiao-Qiang, Sun; Lan-Ting, Ji; Guo-Bing, He; Xi-Bin, Wang; Yun-Ji, Yi; Chang-Ming, Chen; Fei, Wang; Da-Ming, Zhang

    2016-05-01

    Visible light variable optical attenuators (VOA) are essential devices in the application of channel power regulation and equalization in wavelength-division multiplexing cross-connect nodes in plastic optical fiber (POF) transmission systems. In this paper, a polymer/silica hybrid waveguide thermo-optic attenuator based on multimode interference (MMI) coupler is designed and fabricated to operate at 650 nm. The single-mode transmission condition, MMI coupler, and transition taper dimensions are optimized through the beam propagation method. Thermal analysis based on material properties provides the optimized heater placement angle. The fabricated VOA presents an attenuation of 26.5 dB with a 21-mW electrical input power at 650 nm. The rise time and fall time are 51.99 and 192 μs, respectively. The time-stability measurement results prove its working reliability. Project supported by the National Natural Science Foundation of China (Grant Nos. 61205032, 61475061, 61405070, 61177027, 61275033, and 61261130586) and the Science and Technology Development Plan of Jilin Province, China (Grant No. 20140519006JH).

  14. Bifunctionalized hybrid silica spheres by hydrolytic cocondensation of 3-aminopropyltriethoxysilane and vinyltriethoxysilane.

    Science.gov (United States)

    Nair, Bindu Prasannakumaran; Pavithran, Chorappan

    2010-01-19

    Facile, surfactant free synthetic strategy for bifunctionalized hybrid silica spheres (HS) with structural ordering is presented. HS was prepared by casting and drying of stable siloxane solution from hydrolytic co-condensation of 3-aminopropyltriethoxysilane (AS) and vinyltriethoxysilane (VS) with AS:VS mole ratio of 1:3 in ethanol/water mixture. Spheres of size in the range of 250 nm to 2.5 microm were produced by adjusting the concentration of reacted siloxane solution using ethanol. Characterization by FTIR, XRD, TGA, and DSC revealed that the HS was formed from coprecipitation of fully condensed polyhedral oligomeric silsesquioxane (POSS) bilayer and incompletely condensed siloxanes (SIL) produced during drying. Formation of POSS bilayer was confirmed by intercalating and stabilizing POSS within a smectite clay and characterizing the modified clay. XRD, FTIR, SEM, and HRTEM of HS heated to 170 degrees C revealed transformation from disordered into ordered lamellar structure of POSS bilayer assembly and siloxane network due to rearrangement and densification of low melting SIL.

  15. Silica-lipid hybrid microcapsules: influence of lipid and emulsifier type on in vitro performance.

    Science.gov (United States)

    Lim, Li Hui; Tan, Angel; Simovic, Spomenka; Prestidge, Clive A

    2011-05-16

    This study reports on the physicochemical characterisation and in vitro investigations of macro-porous silica-lipid hybrid (SLH) microcapsules when formulated using various lipids: long-chain triglycerides (LCT), medium-chain triglycerides (MCT), medium-chain mono-, diglycerides (MCMDG); and emulsifiers: anionic lecithin and cationic oleylamine. For the lipophilic compound coumarin 102 (logP=4.09), a complete and immediate in vitro release was attained for the SLH microcapsules under simulated intestinal sink conditions. The in vitro digestion study of various types of SLH microcapsules demonstrates: (i) reduced variability and enhanced lipid digestibility for the MCMDG-based microcapsules (i.e. 90-100% lipolysis) in comparison with an equivalent lipid solution and emulsion (50-90% lipolysis); and (ii) more controllable digestion kinetics for the LCT-based microcapsules which produce a lipolysis rate higher than that of a lipid solution but lower than that of a lipid emulsion. The drug phase partition results show approximately 5- to 17-fold increase in the drug solubilisation degree resulting from the digestion of MCT and MCMDG-based microcapsules (116 μg/mL), and LCT-based microcapsules (416 μg/mL) in comparison with the blank micellar medium (24 μg/mL). In conclusion, the SLH microcapsules could be tailored to manipulate the digestion patterns of both medium- and long-chain lipids in order to maximise the drug solubilisation capacity. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Preparation and characterization of phosphorylated Zr-doped hybrid silica/PSF composite membrane.

    Science.gov (United States)

    Zhang, Yuqing; Jin, Zhenhua; Shan, Xing; Sunarso, Jaka; Cui, Ping

    2011-02-15

    Polysulfone (PSF) membranes are broadly applied in many fields owing to good physicochemical stability, resistance to oxidation and chlorine. But when treated with wastewater containing oil, PSF membranes are easy to be contaminated for its hydrophobicity, which can result in the declining of flux and lifespan of the membrane and limit their application in large scale. To enhance the capability of PSF membrane in the above circumstances, phosphorylated Zr-doped hybrid silica particles (SZP particles) were firstly prepared. SZP particles have various point defects inside their structure and lots of hydroxide radicals on their surface. SZP particles were added to the porous matrix of PSF to prepare a novel composite membrane (SZP/PSF) through a phase inversion process. Finally, the optimum preparation conditions of SZP/PSF composite membranes were determined. The optimum conditions are: the mass ratio of PSF, PEG400 and SZP is 12:10:10; ultrasound 10 min inside each 30 min; the pre-evaporating time is 10s. Optimized SZP/PSF composite membrane was characterized by scanning electron microscope (SEM) and ultrafiltration experiment. The results indicate that SZP particles can be uniformly dispersed in SZP/PSF composite membranes with excellent hydrophilic property, antifouling capability and tensile strength. Therefore, it can be concluded that the optimized SZP/PSF composite membrane is desirable in the treatment of wastewater containing oil and wastewater.

  17. Entrapping quercetin in silica/polyethylene glycol hybrid materials: Chemical characterization and biocompatibility.

    Science.gov (United States)

    Catauro, Michelina; Bollino, Flavia; Nocera, Paola; Piccolella, Simona; Pacifico, Severina

    2016-11-01

    Sol-gel synthesis was exploited to entrap quercetin, a natural occurring antioxidant polyphenol, in silica-based hybrid materials, which differed in their polyethylene glycol (PEG) content (6, 12, 24 and 50wt%). The materials obtained, whose nano-composite nature was ascertained by Scanning Electron Microscopy (SEM), were chemically characterized by Fourier Transform InfraRed (FT-IR) and UV-Vis spectroscopies. The results prove that a reaction between the polymer and the drug occurred. Bioactivity tests showed their ability to induce hydroxyapatite nucleation on the sample surfaces. The direct contact method was applied to screen the cytotoxicity of the synthetized materials towards fibroblast NIH 3T3 cells, commonly used for in vitro biocompatibility studies, and three nervous system cell lines (neuroblastoma SH-SY5Y, glioma U251, and pheochromocytoma PC12 cell lines), adopted as models in oxidative stress related studies. Using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay NIH 3T3 proliferation was assessed and the morphology was not compromised by direct exposure to the materials. Analogously, PC-12, and U-251 cell lines were not affected by new materials. SH-SY5Y appeared to be the most sensitive cell line with cytotoxic effects of 20-35%. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Transparent superhydrophobic/translucent superamphiphobic coatings based on silica-fluoropolymer hybrid nanoparticles.

    Science.gov (United States)

    Lee, Seung Goo; Ham, Dong Seok; Lee, Dong Yun; Bong, Hyojin; Cho, Kilwon

    2013-12-03

    This paper describes a simple approach to prepare a transparent superhydrophobic coating and a translucent superamphiphobic coating via spraying silica-fluoropolymer hybrid nanoparticles (SFNs) without any pre- or post-treatment of substrates; these nanoparticles create both microscale and nanoscale roughness, and fluoropolymer acts as a low surface energy binder. We also demonstrate the effects of varying the concentration of the SFN sol on the water and hexadecane repellency and on the transparency of the coated glass substrates. An increase in the concentration of the sol facilitates the transition between the superhydrophobic/transparent and superamphiphobic/translucent states. This transition results from an increase in the discontinuities in the three-phase (solid-liquid-gas) contact line and in the light scattering properties due to micropapillae tuned by varying the concentration of the sol. This versatile and controllable approach can be applied to a variety of substrates over large areas and may provide a wide range of applications for self-cleaning coatings of optoelectronics, liquid-repellent coatings, and microfluidic systems.

  19. Hybrid monolith sorbent of polypyrrole-coated graphene oxide incorporated into a polyvinyl alcohol cryogel for extraction and enrichment of sulfonamides from water samples.

    Science.gov (United States)

    Chullasat, Kochaporn; Nurerk, Piyaluk; Kanatharana, Proespichaya; Kueseng, Pamornrat; Sukchuay, Thanyaporn; Bunkoed, Opas

    2017-04-08

    A hybrid monolith sorbent of polypyrrole-coated graphene oxide embedded in polyvinyl alcohol cryogel was prepared and used as an effective solid phase extraction sorbent for the determination of trace sulfonamides. The large surface areas with many adsorption sites of polypyrrole and graphene oxide facilitated the high adsorption of sulfonamides via hydrogen bonding, π-π and hydrophobic interactions. The high porosity of the polyvinyl alcohol cryogel helped to reduce the back pressure that occurs in a conventional packed solid phase extraction cartridge. The effecting parameters on the extraction efficiency including the type of sorbent, the polymerization time, desorption conditions, the sample pH, the sample volume, the sample flow rate, and ionic strength were investigated and optimized. Under the optimum conditions, the developed method provided a wide linear range from 0.20 to 100.0 μg L(-1) for sulfadiazine, sulfathiazole and sulfamerazine; and from 0.10 to 100 μg L(-1) for sulfamethazine, sulfamonomethoxine and sulfadimethoxine. The limits of detection were 0.20 μg L(-1) for sulfadiazine, sulfathiazole and sulfamerazine; and 0.10 μg L(-1) for sulfamethazine, sulfamonomethoxine and sulfadimethoxine. The developed hybrid monolith polypyrrole-coated graphene oxide embedded in the polyvinyl alcohol cryogel sorbent provided good recoveries in the range of 85.5-99.0% with RSDs of less than 5.0%. The sorbent offered a good reproducibility, was robust and can be reused at least 10 times. It was successfully applied for the extraction and enrichment of sulfonamides from normal and supplemented water samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Solid-State Conversion Chemistry of Multicomponent Nanocrystals Cast in a Hollow Silica Nanosphere: Morphology-Controlled Syntheses of Hybrid Nanocrystals.

    Science.gov (United States)

    Kim, Yeon Jun; Choi, Jung Kyu; Lee, Dong-Gyu; Baek, Kyungjoon; Oh, Sang Ho; Lee, In Su

    2015-11-24

    During thermal transformation of multicomponent nanocrystals in a silica nanosphere, FeAuPd alloy nanocrystals migrate outward and thereby leave a cavity in the silica matrix. Oxidation then converts these nanocrystals back into phase-segregated hybrid nanocrystals, AuPd@Fe3O4, with various morphologies. The FeAuPd-to-AuPd@Fe3O4 transformation was cast by the in situ generated hollow silica mold. Therefore, the morphological parameters of the transformed AuPd@Fe3O4 are defined by the degree of migration of the FeAuPd in the hollow silica nanoshell. This hollow silica-cast nanocrystal conversion was studied to develop a solid state protocol that can be used to produce a range of hybrid nanocrystals and that allows for systematic and sophisticated control of the resulting morphologies.

  1. Chemical and mechanical properties of silica hybrid films from NaOH catalyzed sols for micromachining with diamond cutting tools

    Energy Technology Data Exchange (ETDEWEB)

    Prenzel, T., E-mail: tprenzel@uni-bremen.de [Stiftung Institut für Werkstofftechnik, Badgasteiner Str. 3, 28359 Bremen (Germany); Mehner, A. [Stiftung Institut für Werkstofftechnik, Badgasteiner Str. 3, 28359 Bremen (Germany); Lucca, D.A.; Qi, Y.; Harriman, T.A. [School of Mechanical and Aerospace Engineering, 218 Engineering North, Oklahoma State University, Stillwater, OK 74078 (United States); Mutlugünes, Y. [Labor für Mikrozerspanung — LFM, Badgasteiner Str. 2, 28359 Bremen (Germany); Shojaee, S.A. [School of Mechanical and Aerospace Engineering, 218 Engineering North, Oklahoma State University, Stillwater, OK 74078 (United States); Wang, Y.Q.; Williams, D. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Nastasi, M. [Nebraska Center for Energy Sciences Research, University of Nebraska, 230 Whittier Research Center, 2200 Vine Street Lincoln, NE 68583-0857 (United States); Zoch, H.-W. [Stiftung Institut für Werkstofftechnik, Badgasteiner Str. 3, 28359 Bremen (Germany); Swiderek, P. [Institute of Applied and Physical Chemistry, University of Bremen, Leobener Straße, 28359 Bremen (Germany)

    2013-03-01

    Manufacturing of microstructured mold surfaces was realized by the micromachining of thick sol–gel silica hybrid coatings. The films were deposited onto pre-machined steel molds by spin coating using NaOH-catalyzed sols from organosilicate precursors. The effect of the sol synthesis and the heat treatment on the mechanical and chemical properties of these films was studied in order to develop thick and crack-free films with appropriate properties for micromachining with diamond cutting tools. The hardness was measured by nanoindentation as a function of the heat treatment temperature. The transition from soft organic gel films to hard glass-like films due to the thermal treatment was characterized by X-ray photoelectron spectroscopy, elastic recoil detection, and Raman and infrared spectroscopies. The films from NaOH catalyzed sols showed a complex transition from aliphatic carbon originating from hydrocarbon groups to carbonates, carboxylates and disordered carbon clusters. - Highlights: ► Thick silica hybrid films were micromachined with diamond cutting tools. ► The nanoindentation hardness increased with the heat treatment temperature. ► The role of sodium hydroxide in base catalyzed silica sols was studied. ► Formation of carbonates, carboxylates and disordered carbon was observed.

  2. Effect of chemically modified silicas on the properties of hybrid gel electrolyte for Li-ion batteries

    Science.gov (United States)

    Walkowiak, Mariusz; Zalewska, Aldona; Jesionowski, Teofil; Waszak, Daniel; Czajka, Bogdan

    The aim of the presented work was to perform a preliminary study the physico-chemical properties of hybrid organic-inorganic gel electrolytes for Li-ion batteries based on the PVdF-HFP polymeric matrix and surface modified fumed silicas. Modifications were done by means of the so-called dry method using seven different silanes differing in the nature of the principal functional group: N-2-(aminoethyl)-3-amino propyltrimethoxysilane, 3-glycidoxypropyltrimetoxysilane, 3-mercaptopropyltrimetoxysilane, n-octyltriethoxysilane, 3-(chloropropyl)trimethoxysilane, 3-methacryloxypropyltrimetoxysilane, vinyltrimethoxysilane. The PVdF-HFP gels were prepared according to the so-called Bellcore process (two-step method). Impact of the silicas surface functionality on the degree of crystallinity of the polymeric membranes was studied using the differential scanning calorimetry technique. Applicability of the prepared gel electrolytes for the Li-ion technology was estimated on the basis of specific conductivity measurements. It was shown that modification of the silica surface by most of the silanes causes an increase in the gel specific conductivity by about two orders of magnitude as compared to gel with unmodified silica.

  3. Effect of chemically modified silicas on the properties of hybrid gel electrolyte for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Walkowiak, Mariusz; Waszak, Daniel; Czajka, Bogdan [Central Laboratory of Batteries and Cells, ul. Forteczna 12, 61-362 Poznan (Poland); Zalewska, Aldona [Warsaw University of Technology, Department of Chemistry, ul. Noakowskiego 3, 00-664 Warsaw (Poland); Jesionowski, Teofil [Poznan University of Technology, Institute of Chemical Technology and Engineering, Pl. Marii Sklodowskiej-Curie 2, 60-965 Poznan (Poland)

    2006-09-13

    The aim of the presented work was to perform a preliminary study the physico-chemical properties of hybrid organic-inorganic gel electrolytes for Li-ion batteries based on the PVdF-HFP polymeric matrix and surface modified fumed silicas. Modifications were done by means of the so-called dry method using seven different silanes differing in the nature of the principal functional group: N-2-(aminoethyl)-3-amino propyltrimethoxysilane, 3-glycidoxypropyltrimetoxysilane, 3-mercaptopropyltrimetoxysilane, n-octyltriethoxysilane, 3-(chloropropyl)trimethoxysilane, 3-methacryloxypropyltrimetoxysilane, vinyltrimethoxysilane. The PVdF-HFP gels were prepared according to the so-called Bellcore process (two-step method). Impact of the silicas surface functionality on the degree of crystallinity of the polymeric membranes was studied using the differential scanning calorimetry technique. Applicability of the prepared gel electrolytes for the Li-ion technology was estimated on the basis of specific conductivity measurements. It was shown that modification of the silica surface by most of the silanes causes an increase in the gel specific conductivity by about two orders of magnitude as compared to gel with unmodified silica. (author)

  4. Hybrid life cycle assessment comparison of colloidal silica and cement grouted soil barrier remediation technologies.

    Science.gov (United States)

    Gallagher, Patricia M; Spatari, Sabrina; Cucura, Jeffrey

    2013-04-15

    Site remediation involves balancing numerous costs and benefits but often neglects the environmental impacts over the entire project life cycle. Life cycle assessment (LCA) offers a framework for inclusion of global environmental "systems-level" decision metrics in combination with technological and cost analysis. We compare colloidal silica (CS) and cement grouted soil barrier remediation technologies for soils affected by low level radionuclides at a U.S. Superfund site using hybrid LCA methods. CS is a new, high performance grouting material installed using permeation grouting techniques. Cement, a more traditional grouting material, is typically installed using jet grouting techniques. Life cycle impacts were evaluated using the US EPA TRACI 2 model. Results show the highest life cycle environmental impacts for the CS barrier occur during materials production and transportation to the site. In general, the life cycle impacts for the cement barrier were dominated by materials production; however, in the extreme scenario the life cycle impacts were dominated by truck transportation of spoils to a distant, off-site radioactive waste facility. It is only in the extreme scenario tested in which soils are transported by truck (Option 2) that spoils waste transport dominates LCIA results. Life cycle environmental impacts for both grout barriers were most sensitive to resource input requirements for manufacturing volumes and transportation. Uncertainty associated with the efficacy of new technology such as CS over its required design life indicates that barrier replacement could increase its life cycle environmental impact above that of the cement barrier. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Iodinated silica/porphyrin hybrid nanoparticles for X-ray computed tomography/fluorescence dual-modal imaging of tumors

    Directory of Open Access Journals (Sweden)

    Koichiro Hayashi

    2014-12-01

    Full Text Available Silica nanoparticles containing covalently linked iodine and a near-infrared (NIR fluorescence dye, namely porphyrin, have been synthesized through a one-pot sol–gel reaction. These particles are called iodinated silica/porphyrin hybrid nanoparticles (ISP HNPs. The ISP HNPs have both high X-ray absorption coefficient and NIR fluorescence. The ISP HNPs modified with folic acid (FA and polyethylene glycol (PEG, denoted as FA-PEG-ISP HNPs, enabled the successful visualization of tumors in mice by both X-ray computed tomography (CT and fluorescence imaging (FI. Thus, the FA-PEG-ISP HNPs are useful as contrast agents or probes for CT/FI dual-modal imaging.

  6. Micelle swelling agent derived cavities for increasing hydrophobic organic compound removal efficiency by mesoporous micelle@silica hybrid materials

    KAUST Repository

    Shi, Yifeng

    2012-06-01

    Mesoporous micelle@silica hybrid materials with 2D hexagonal mesostructures were synthesized as reusable sorbents for hydrophobic organic compounds (HOCs) removal by a facile one-step aqueous solution synthesis using 3-(trimethoxysily)propyl-octadecyldimethyl-ammonium chloride (TPODAC) as a structure directing agent. The mesopores were generated by adding micelle swelling agent, 1,3,5-trimethyl benzene, during the synthesis and removing it afterward, which was demonstrated to greatly increase the HOC removal efficiency. In this material, TPODAC surfactant is directly anchored on the pore surface of mesoporous silica via SiOSi covalent bond after the synthesis due to its reactive Si(OCH 3) 3 head group, and thus makes the synthesized materials can be easily regenerated for reuse. The obtained materials show great potential in water treatment as pollutants sorbents. © 2011 Elsevier Inc. All rights reserved.

  7. THE STRUCTURE AND PROPERTIES OF CHITOSAN/PPLYETHYLENE GLYCOL/SILICA TERNARY HYBRID ORGANIC-NORGANIC FILMS

    Institute of Scientific and Technical Information of China (English)

    Rui Song; Rui Xue; Ling-hao He; Ying Liu; Qiao-ling Xiao

    2008-01-01

    The ternary hybrid films consisting of chitosan(CS),polyethylene glycol(PEG)and nano-sized silica which was surface-modified by amino groups(RNSA)were prepared.The structures of the blend membranes were characterized by attenuation total reflection-infrared spectroscopy(ATR-IR),X-ray diffraction(XRD),optical microscopy(OM)and differential scanning calorimetry (DSC).The results showed that the addition of silica affected not only the distribution and crystallinity of PEG on the sample surface.but also the phase coarseness and the crystalline structure of chitosan in the blend system.Moreover,PEG changed the crystalline structure of chitosan.Upon annealing(at 100℃ for 1 h),the blends would show the altered crystalline structure of chitosan,the reinforced phase coarseness.as well as the decreased miscibility and interaction between chitosan and PEG.

  8. Synthesis, Processing, and Characterization of Inorganic-Organic Hybrid Cross-Linked Silica, Organic Polyimide, and Inorganic Aluminosilicate Aerogels

    Science.gov (United States)

    Nguyen, Baochau N.; Guo, Haiquan N.; McCorkle, Linda S.

    2014-01-01

    As aerospace applications become ever more demanding, novel insulation materials with lower thermal conductivity, lighter weight and higher use temperature are required to fit the aerospace application needs. Having nanopores and high porosity, aerogels are superior thermal insulators, among other things. The use of silica aerogels in general is quite restricted due to their inherent fragility, hygroscopic nature, and poor mechanical properties, especially in extereme aerospace environments. Our research goal is to develop aerogels with better mechanical and environmental stability for a variety of aeronautic and space applications including space suit insulation for planetary surface missions, insulation for inflatable structures for habitats, inflatable aerodynamic decelerators for entry, descent and landing (EDL) operations, and cryotank insulation for advance space propulsion systems. Different type of aerogels including organic-inorganic polymer reinforced (hybrid) silica-based aerogels, polyimide aerogels and inorganic aluminosilicate aerogels have been developed and examined.

  9. Thermal Stabilization of EDFA gain by hybrid concatenation of antimony-doped silica EDF

    Institute of Scientific and Technical Information of China (English)

    Young-Eun Im; Uh-Chan Ryu; P. Babu; Won-Taek Han; K. Oh; David J. DiGiovanni; Baishi Wang; Anand Hariharan

    2003-01-01

    Sb-doped silica EDF showed an opposite temperature dependent gain profile compared to Al-doped silica EDF. Concatenation of those two EDFs showed a gain variation less than ± 0.4 dB over 40nm of C-band with the 15dB gain, in the temperature range of - 40 to + 80℃.

  10. Thermal Stabilization of EDFA gain by hybrid concatenation of antimony-doped silica EDF

    Institute of Scientific and Technical Information of China (English)

    Young-Eun; Im; Uh-Chan; Ryu; P.; Babu; Won-Taek; Han; K.; Oh; David; J.; DiGiovanni; Baishi; Wang; Anand; Hariharan

    2003-01-01

    Sb-doped silica EDF showed an opposite temperature dependent gain profile compared to Al-doped silica EDF. Concatenation of those two EDFs showed a gain variation less than ?0.4 dB over 40nm of C-band with the 15dB gain, in the temperature range of- 40 to + 80℃.

  11. Full-mouth rehabilitation with monolithic CAD/CAM-fabricated hybrid and all-ceramic materials: A case report and 3-year follow up.

    Science.gov (United States)

    Selz, Christian F; Vuck, Alexander; Guess, Petra C

    2016-02-01

    Esthetic full-mouth rehabilitation represents a great challenge for clinicians and dental technicians. Computer-aided design/ computer-assisted manufacture (CAD/CAM) technology and novel ceramic materials in combination with adhesive cementation provide a reliable, predictable, and economic workflow. Polychromatic feldspathic CAD/CAM ceramics that are specifically designed for anterior indications result in superior esthetics, whereas novel CAD/CAM hybrid ceramics provide sufficient fracture resistance and adsorption of the occlusal load in posterior areas. Screw-retained monolithic CAD/CAM lithium disilicate crowns (ie, hybrid abutment crowns) represent a reliable and time- and cost-efficient prosthetic implant solution. This case report details a CAD/CAM approach to the full-arch rehabilitation of a 65-year-old patient with toothand implant-supported restorations and provides an overview of the applied CAD/CAM materials and the utilized chairside intraoral scanner. The esthetics, functional occlusion, and gingival and peri-implant tissues remained stable over a follow-up period of 3 years. No signs of fractures within the restorations were observed.

  12. Monolithic integration of hybrid III-V/Si lasers and Si-based modulators for data transmission up to 25Gbps

    Science.gov (United States)

    Ferrotti, Thomas; Blampey, Benjamin; Jany, Christophe; Duprez, Hélène; Chantre, Alain; Boeuf, Frédéric; Seassal, Christian; Ben Bakir, Badhise

    2017-02-01

    In this paper, the 200mm silicon-on-insulator (SOI) platform is used to demonstrate the monolithic co-integration of hybrid III-V/silicon Distributed Bragg Reflector (DBR) tunable lasers and silicon Mach-Zehnder modulator (MZMs), to achieve fully integrated hybrid transmitters for silicon photonics. The design of each active component, as well as the fabrication process steps of the whole architecture are described in details. Data transmission rate up to 25Gb/s has been reached for transmitters using MZMs with active lengths of 2mm and 4mm. Extinction ratios of respectively 2.9dB and 4.7dB are obtained by applying drive voltages of 2.5V peak-to-peak on the MZMs. 25Gb/s data transmission is demonstrated at 1303.5nm and 1315.8nm, with the possibility to tune the operating wavelength by up to 8.5nm in each case, by using metallic heaters above the lasers Bragg reflectors.

  13. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    Science.gov (United States)

    Wang, Daojing; Yang, Peidong; Kim, Woong; Fan, Rong

    2011-09-20

    Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

  14. Monolithic MACS micro resonators

    Science.gov (United States)

    Lehmann-Horn, J. A.; Jacquinot, J.-F.; Ginefri, J. C.; Bonhomme, C.; Sakellariou, D.

    2016-10-01

    Magic Angle Coil Spinning (MACS) aids improving the intrinsically low NMR sensitivity of heterogeneous microscopic samples. We report on the design and testing of a new type of monolithic 2D MACS resonators to overcome known limitations of conventional micro coils. The resonators' conductors were printed on dielectric substrate and tuned without utilizing lumped element capacitors. Self-resonance conditions have been computed by a hybrid FEM-MoM technique. Preliminary results reported here indicate robust mechanical stability, reduced eddy currents heating and negligible susceptibility effects. The gain in B1 /√{ P } is in agreement with the NMR sensitivity enhancement according to the principle of reciprocity. A sensitivity enhancement larger than 3 has been achieved in a monolithic micro resonator inside a standard 4 mm rotor at 500 MHz. These 2D resonators could offer higher performance micro-detection and ease of use of heterogeneous microscopic substances such as biomedical samples, microscopic specimens and thin film materials.

  15. Hard macrocellular silica Si(HIPE) foams templating micro/macroporous carbonaceous monoliths: applications as lithium ion battery negative electrodes and electrochemical capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Brun, Nicolas [Universite de Bordeaux, Centre de Recherche Paul Pascal, UPR 8641-CNRS, Pessac (France); Universite de Bordeaux, Institut des Sciences Moleculaires CNRS-UMR, Talence (France); Prabaharan, Savari R.S. [Laboratoire de Reactivite et Chimie des Solides, UMR CNRS 6007 Universite de Picardie Jules Verne, Amiens (France); Faculty of Engineering and Computer Science, University of Nottingham, Malaysia Campus Jalan Broga, Semenyih, Selangor (Malaysia); Morcrette, Mathieu [Laboratoire de Reactivite et Chimie des Solides, UMR CNRS 6007 Universite de Picardie Jules Verne, Amiens (France); Sanchez, Clement [Laboratoire de Chimie de la Matiere Condensee de Paris, Universite Paris 06, Paris (France); Pecastaings, Gilles; Soum, Alain [Laboratoire de Chimie des Polymeres Organiques UMR 5629 CNRS, Universite Bordeaux-1, Pessac (France); Derre, Alain; Backov, Renal [Universite de Bordeaux, Centre de Recherche Paul Pascal, UPR 8641-CNRS, Pessac (France); Deleuze, Herve; Birot, Marc [Universite de Bordeaux, Institut des Sciences Moleculaires CNRS-UMR, Talence (France)

    2009-10-09

    By using Si(HIPEs) as hard, exotemplating matrices, interconnected macro-/microporous carbon monolith-type materials with a surface area of around 600 m{sup 2} g{sup -1} are synthesized and shaped. The carbonaceous foams exhibit a conductivity of 20 S cm{sup -1}, addressed with excellent mechanical properties (Young's modulus of 0.2 GPa and toughness of 13 J g{sup -1}, when the carbon core is optimized). The above-mentioned specificities, combined with the fact that the external shape and size can be easily designed on demand, are of primary importance for applications. The functionality of these carbonaceous monoliths is tested as both an electrochemical capacitor and a lithium ion negative electrode. The electrochemical capacitors' voltage-current profiles exhibit a non-ideal rectangular response, confirming the double-layer behavior of the carbon studied, while the charge-discharge current profile of the electric double-layer capacitor is directly proportional to the scan where the current response during charge and discharge exhibits high reversibility. When acting as a lithium ion negative electrode, after initial irreversibility, a good cyclability is obtained, associated with a stable capacity of 200 mA h g{sup -1} during the first 50 cycles at a reasonable current density (C/10). (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  16. High-performance liquid chromatography analysis of polyacetylenes and polyenes in Echinacea pallida by using a monolithic reversed-phase silica column.

    Science.gov (United States)

    Pellati, Federica; Calò, Samuele; Benvenuti, Stefania

    2007-05-11

    In this study, a RP-HPLC method for the analysis of polyacetylenes and polyenes in Echinacea pallida roots and phytopharmaceuticals was developed. The reference compounds used for quantification were isolated from the plant material and their structures were determined on the basis of the analysis of UV, IR, NMR and MS data. The complete structure elucidation of three compounds, namely 8-hydroxy-tetradec-(9E)-ene-11,13-diyn-2-one (1), tetradec-(8Z)-ene-11,13-diyn-2-one (6) and pentadec-(8Z)-en-2-one (9) is described. In the analysis of the n-hexane extracts of E. pallida roots, the comparison between conventional and monolithic columns showed that the elution order in both cases is identical and the selectivity is equivalent. However, the retention times achieved by the monolithic column are shorter, resulting in a faster separation (20 min). Therefore, the analyses were carried out on a Chromolith Performance RP-18e (100 mm x 4.6 mm i.d.), with a gradient mobile phase composed by H(2)O and ACN at the flow rate of 2 mL/min. The column was thermostatted at 20 degrees C. The photodiode array detector monitored the eluent at 210 nm. The validation procedure confirmed that this technique affords reliable analysis of these components and is appropriate for the quality control of complex matrices, such as E. pallida roots and phytopharmaceuticals.

  17. Enhanced resolution of a POF-based refractometer using a novel hybrid silica-fiber POF directional coupler

    Science.gov (United States)

    Farrell, Gerald; Gao, Cheng

    2008-04-01

    For a plastic optical fiber based refractometer system the influence of the directivity of the fiber coupler on the achievable resolution is analysed. It is also shown that provided the fiber length between the sensing tip and receiver is less that 2 m that interference due to Rayleigh backscatter will not comprise operation of the refractometer. A novel coupler based on a hybrid silica fiber-plastic fiber design is used experimentally to provide a comparison to the modelled results. It is shown that the high directivity (>35 dB) of this coupler can significantly enhance the resolution of the refractometer.

  18. Silica/polyacrylonitrile hybrid nanofiber membrane separators via sol-gel and electrospinning techniques for lithium-ion batteries

    Science.gov (United States)

    Yanilmaz, Meltem; Lu, Yao; Zhu, Jiadeng; Zhang, Xiangwu

    2016-05-01

    Silica/polyacrylonitrile (SiO2/PAN) hybrid nanofiber membranes were fabricated by using sol-gel and electrospinning techniques and their electrochemical performance was evaluated for use as separators in lithium-ion batteries. The aim of this study was to design high-performance separator membranes with enhanced electrochemical performance and good thermal stability compared to microporous polyolefin membranes. In this study, SiO2 nanoparticle content up to 27 wt% was achieved in the membranes by using sol-gel technique. It was found that SiO2/PAN hybrid nanofiber membranes had superior electrochemical performance with good thermal stability due to their high SiO2 content and large porosity. Compared with commercial microporous polyolefin membranes, SiO2/PAN hybrid nanofiber membranes had larger liquid electrolyte uptake, higher electrochemical oxidation limit, and lower interfacial resistance with lithium. SiO2/PAN hybrid nanofiber membranes with different SiO2 contents (0, 16, 19 and 27 wt%) were also assembled into lithium/lithium iron phosphate cells, and high cell capacities and good cycling performance were demonstrated at room temperature. In addition, cells using SiO2/PAN hybrid nanofiber membranes with high SiO2 contents showed superior C-rate performance compared to those with low SiO2 contents and commercial microporous polyolefin membrane.

  19. Sulfonated poly(ether ether ketone)/mesoporous silica hybrid membrane for high performance vanadium redox flow battery

    Science.gov (United States)

    Li, Zhaohua; Dai, Wenjing; Yu, Lihong; Xi, Jingyu; Qiu, Xinping; Chen, Liquan

    2014-07-01

    Hybrid membranes of sulfonated poly(ether ether ketone) (SPEEK) and mesoporous silica SBA-15 are prepared with various mass ratios for vanadium redox flow battery (VRB) application and investigated in detail. The hybrid membranes are dense and homogeneous with no visible hole as the SEM and EDX images shown. With the increasing of SBA-15 mass ratio, the physicochemical property, VO2+ permeability, mechanical property and thermal stability of hybrid membranes exhibit good trends, which can be attributed to the interaction between SPEEK and SBA-15. The hybrid membrane with 20 wt.% SBA-15 (termed as S/SBA-15 20) shows the VRB single cell performance of CE 96.3% and EE 88.1% at 60 mA cm-2 due to its good balance of proton conductivity and VO2+ permeability, while Nafion 117 membrane shows the cell performance of CE 92.2% and EE 81.0%. Besides, the S/SBA-15 20 membrane shows stable cell performance of highly stable efficiency and slower discharge capacity decline during 120 cycles at 60 mA cm-2. Therefore, the SPEEK/SBA-15 hybrid membranes with optimized mass ratio and excellent VRB performance can be achieved, exhibiting good potential usage in VRB systems.

  20. Hybrid Nanomaterials Based on Iron Oxide Nanoparticles and Mesoporous Silica Nanoparticles: Overcoming Challenges in Current Cancer Treatments

    Directory of Open Access Journals (Sweden)

    Merlis P. Alvarez-Berríos

    2016-01-01

    Full Text Available The current approaches used for the treatment of cancer face some clinical limitations such as induction of severe side effects, multidrug resistance (MDR, and low specificity toward metastatic cancer cells. Hybrid nanomaterials hold a great potential to overcome all these challenges. Among hybrid nanoparticles, those based on mesoporous silica and iron oxide nanoparticles (MSNs and IONPs have gained a privileged place in the biomedical field because of their outstanding properties. There are many studies demonstrating their effectiveness as drug delivery systems, nanoheaters, and imaging contrast agents. This review summarizes the advances related to the utilization of IONPs and MSNs for reducing side effects, overcoming MDR, and inhibiting metastasis. Furthermore, we give a future perspective of the clinical application of these technologies.

  1. Ordered and disordered evolution of the pore mesostructure in hybrid silica anti-reflective films obtained by one-pot self-assembly method

    Energy Technology Data Exchange (ETDEWEB)

    Ghazzal, Mohamed N., E-mail: g_nawfel@yahoo.fr; Debecker, Damien P.; Gaigneaux, Eric M.

    2016-07-29

    Hybrid mesoporous silica films were prepared in acid-catalysed medium using a one-pot self-assembly method. A gradual content of methyl groups was introduced into the inorganic framework by co-condensation of tetraethyl orthosilicate and methyltriethoxysilane. To better understand how the ordered and disordered transition occurs in mesoporous hybrid organosilica sytem as function of the MTES molar ratio in the starting solution, textural, chemical and optical properties of the films were studied by transmission electronic microscopy (TEM), grazing-incident small angle X-ray scattering (GISAXS), transmission Fourier transformed infrared (FTIR) and UV–visible spectroscopy. Increasing the loading of the incorporated organic groups (up to 40% in the starting solution) led simultaneously to a disorganization of the pore mesostructure and a reduction in the pore diameter. Concomitantly, a disordered domain of the silica rings in the walls was observed, which created bond strains in the silica wall contributing also to the disorganization of the pore mesostructure. Furthermore, an optimal MTES content was identified in order to obtain antireflection coatings, exhibiting low reflection in the visible range. - Highlights: • Mesoporous hybrid silica films where prepared by one-pot co-condensation of MTES and TEOS. • Ordered and disordered mesostructures were studied as function as variable MTES molar ratio. • A rearrangement of the silica cyclic species occurred as the molar ratio of MTES increases. • Transmittance of the silica coatings is affected by the MTES molar ratio.

  2. Core-Shell-Corona Silica Hybrid Nanoparticles Templated by Spherical Polyelectrolyte Brushes: A Study by Small Angle X-ray Scattering.

    Science.gov (United States)

    Han, Haoya; Li, Li; Wang, Weihua; Tian, Yuchuan; Wang, Yunwei; Wang, Junyou; von Klitzing, Regine; Guo, Xuhong

    2017-09-06

    Core-shell-corona silica/polymer hybrid nanoparticles with narrow size distribution were prepared in the template of spherical polyelectrolyte brushes (SPB) which consist of a solid polystyrene (PS) core densely grafted with linear poly(acrylic acid) (PAA) chains. The microstructure of obtained hybrid nanoparticles was studied by small-angle X-ray scattering (SAXS) and in combination with dynamic light scattering (DLS) and transmission electron microscopy (TEM). The generation of silica shell within the brush is confirmed by the significant increase of the electron density in the shell, and the silica shell showed a unique inner-loose-outer-dense structure, whose thickness is pH sensitive but is insensitive to ionic strength as revealed by fitting SAXS data. After dissolving the PS core, hollow silica nanoparticles were obtained and determined by SAXS, which should be ideal carriers for pH-triggered drug delivery. SAXS is confirmed to be a powerful method to characterize the core-shell-corona silica/polymer hybrid and hollow silica nanoparticles.

  3. Synthesis of ZSM-5 Monoliths with Hierarchical Porosity

    Institute of Scientific and Technical Information of China (English)

    Tong Yangchuan; Zhao Tianbo; Li Fengyan; Zong Baoning; Wang Yue

    2006-01-01

    A new route to synthesize ZSM-5 monoliths with hierarchical pore structure has been referred to in this stud y. The successful incorporation of the macropores and mesopores within the ZSM-5 structure was achieved through transforming the skeleton of the macroporous silica gel into zeolite ZSM-5 using carbon materials as the transitional template. The ZSM-5 crystal covered part of the macroporous material, and provided micropores to the macroporous silica gel. The structure of carbon monolith was studied after dissolving the silica contained in the carbon/silica composite.

  4. Preparation, characterization and luminescent properties of dense nano-silica hybrids loaded with 1,8-naphthalic anhydride.

    Science.gov (United States)

    Wang, Jinpeng; Sun, Jihong; Li, Yuzhen; Wang, Feng

    2014-03-01

    Novel luminescent dense nano-silica hybrid materials (DNSS) modified with different amounts of (3-aminopropyl)triethoxysilane (APTES) and 1,8-naphthalic anhydride (NA) were successfully synthesized via two steps combined with post-grafting methods. Powder X-ray diffraction (XRD), N2-sorption analysis, Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), photoluminescence (PL) spectroscopy and elemental analysis, as well as time-resolved decays were employed to characterize the resultant hybrid materials. The results revealed that luminescent organic molecules had been successfully loaded onto the amine-modified surface of nano-silica spheres. In addition, their fluorescence intensity and characteristic peak of emission spectra changed with increasing amount of APTES and NA additive. In particular, the characteristic peak showed a red shift from 390 to 450 nm, however, this was inconsistent with results calculated on the basis of the elemental analysis data, most probably because of the dispersion behaviors of NA molecules from the aggregating to the monolayer state. These observations demonstrated the existence of a quantum confinement effectiveness of NA-DNSS samples, and therefore a possible mechanism was put forward.

  5. Substrate integrated Lead-Carbon hybrid ultracapacitor with flooded, absorbent glass mat and silica-gel electrolyte configurations

    Indian Academy of Sciences (India)

    A Banerjee; M K Ravikumar; A Jalajakshi; P Suresh Kumar; S A Gaffoor; A K Shukla

    2012-07-01

    Lead-Carbon hybrid ultracapacitors (Pb-C HUCs) with flooded, absorbent-glass-mat (AGM) and silica-gel sulphuric acid electrolyte configurations are developed and performance tested. Pb-C HUCs comprise substrate-integrated PbO2 (SI-PbO2) as positive electrodes and high surface-area carbon with graphite-sheet substrate as negative electrodes. The electrode and silica-gel electrolyte materials are characterized by XRD, XPS, SEM, TEM, Rheometry, BET surface area, and FTIR spectroscopy in conjunction with electrochemistry. Electrochemical performance of SI-PbO2 and carbon electrodes is studied using cyclic voltammetry with constant-current charge and discharge techniques by assembling symmetric electrical-double-layer capacitors and hybrid Pb-C HUCs with a dynamic Pb(porous)/PbSO4 reference electrode. The specific capacitance values for 2 V Pb-C HUCs are found to be 166 F/g, 102 F/g and 152 F/g with a faradaic efficiency of 98%, 92% and 88% for flooded, AGM and gel configurations, respectively.

  6. Evaluation of a Cyclodextrin-silica Hybrid Microporous Composite for the Solid-phase Extraction of Polycyclic Aromatic Hydrocarbons.

    Science.gov (United States)

    Soler-Seguí, Salomé; Belenguer-Sapiña, Carolinakn-Aut-Sei; Amorós, Pedro; Mauri-Aucejo, Adela

    2016-01-01

    Solid-phase extraction (SPE) coupled with high-performance liquid chromatography (HPLC) with fluorescence detection were employed to determine trace polycyclic aromatic hydrocarbons in water samples. In this way, the use of cartridges containing cyclodextrin-silica hybrid microporous solid phases was proposed. The experimental results indicated that the method provided relative standard deviations of below 15% and detection limits recorded were 12, 1.2, 12, 38, 4, 6 and 4 ng L(-1) for benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[g,h,i]perylene, indeno[1,2,3]pyrene, benzo[a]pyrene, dibenzo[a,h]anthracene and benzo[a]anthracene, respectively. Moreover, the method was successfully applied for the determination of these organic compounds in water samples, where they were found to be in the 7 to 580 ng L(-1) range. It can be concluded that the major advantages of cyclodextrin-silica hybrid microporous solid phases are that they reduce the consumption and the toxicity of the solvent and the time consumption of the sample treatment step.

  7. Novel hybrid structure silica/CdTe/molecularly imprinted polymer: synthesis, specific recognition, and quantitative fluorescence detection of bovine hemoglobin.

    Science.gov (United States)

    Li, Dong-Yan; He, Xi-Wen; Chen, Yang; Li, Wen-You; Zhang, Yu-Kui

    2013-12-11

    This work presented a novel strategy for the synthesis of the hybrid structure silica/CdTe/molecularly imprinted polymer (Si-NP/CdTe/MIP) to recognize and detect the template bovine hemoglobin (BHb). First, amino-functionalized silica nanoparticles (Si-NP) and carboxyl-terminated CdTe quantum dots (QDs) were assembled into composite nanoparticles (Si-NP/CdTe) using the EDC (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) chemistry. Next, Si-NP/CdTe/MIP was synthesized by anchoring molecularly imprinted polymer (MIP) layer on the surface of Si-NP/CdTe through the sol-gel technique and surface imprinting technique. The hybrid structure possessed the selectivity of molecular imprinting technique and the sensitivity of CdTe QDs as well as well-defined morphology. The binding experiment and fluorescence method demonstrated its special recognition performance toward the template BHb. Under the optimized conditions, the fluorescence intensity of the Si-NP/CdTe/MIP decreased linearly with the increase of BHb in the concentration range 0.02-2.1 μM, and the detection limit was 9.4 nM. Moreover, the reusability and reproducibility and the successful applications in practical samples indicated the synthesis of Si-NP/CdTe/MIP provided an alternative solution for special recognition and determination of protein from real samples.

  8. Formation of hybrid films from perylenediimide-labeled core-shell silica-polymer nanoparticles.

    Science.gov (United States)

    Ribeiro, Tânia; Fedorov, Aleksander; Baleizão, Carlos; Farinha, José Paulo S

    2013-07-01

    We prepared water-dispersible core-shell nanoparticles with a perylenediimide-labeled silica core and a poly(butyl methacrylate) shell, for application in photoactive high performance coatings. Films cast from water dispersions of the core-shell nanoparticles are flexible and transparent, featuring homogeneously dispersed silica nanoparticles, and exhibiting fluorescence under appropriate excitation. We characterized the film formation process using nanoparticles where the polymer shell has been labeled with either a non-fluorescent N-benzophenone derivative (NBen) or a fluorescent phenanthrene derivative (PheBMA). We used Förster resonance energy transfer (FRET) from PheBMA to NBen to follow the interparticle interdiffusion of the polymer anchored to the silica surface that occurs after the dried dispersions are annealing above the glass transition temperature of the polymer. By calculating the evolution of the FRET quantum efficiency with annealing time, we could estimate the approximate fraction of mixing (fm) between polymer from neighbor particles, and from this, the apparent diffusion coefficients (Dapp) for this process. For long annealing times, the limiting values of fm are slightly lower than for films of pure PBMA particles at similar temperatures (go up to 80% of total possible mixing). The corresponding diffusion coefficients are also very similar to those reported for films of pure PBMA, indicating that the fact that the polymer chains are anchored to the silica particles does not significantly hinder the diffusion process during the initial part of the mixing process. From the temperature dependence of the diffusion coefficients, we found an effective activation energy for diffusion of Ea=38 kcal/mol, very similar to the value obtained for particles of the same polymer without the silica core. With these results, we show that, although the polymer is grafted to the silica surface, polymer interdiffusion during film formation is not significantly

  9. Hybrid glass coatings for optical fibers: effect of coating thickness on strength and dynamic fatigue characteristics of silica fibers

    Science.gov (United States)

    Wojcik, A. B.; Matthewson, M. J.; Castelino, K. T.; Wojcik, J.; Walewski, A.

    2006-04-01

    Specialty optical fibers operating in harsh aerospace environments are typically exposed to high temperatures and elevated humidity. This calls for better performing protective coatings. Recently developed sol-gel derived inorganicorganic hybrid materials called hybrid glass offered improved protective performance as compared to standard dual polymer coated fibers [1]. In this paper we examine the effectiveness of online UV curing for the protective ability of hybrid glass coatings. For this purpose two types of UV-curable hybrid glass candidates representing two different concentrations of acrylate groups were applied online to silica fibers as single and dual coats. Samples of fibers were collected and subjected to dynamic fatigue testing by two-point bending. The stress corrosion parameter, n, as well as the strength of the fibers were determined. Both the strength and n were higher for fibers with two layers of coating as compared to single coatings even when the thickness of both one and two layer coatings was the same. This may be caused by the greater degree of cross linking of the inorganic component when the coating is exposed twice to the heat generated in the UV chamber. Coating materials with reduced acrylate group content had higher values of the fatigue parameter n but at the same time reduced strength.

  10. Well-defined functional mesoporous silica/polymer hybrids prepared by an ICAR ATRP technique integrated with bio-inspired polydopamine chemistry for lithium isotope separation.

    Science.gov (United States)

    Liu, Yuekun; Liu, Xuegang; Ye, Gang; Song, Yang; Liu, Fei; Huo, Xiaomei; Chen, Jing

    2017-05-09

    Mesoporous silica/polymer hybrids with well-preserved mesoporosity were prepared by integrating the initiators for continuous activator regeneration (ICAR) atom transfer radical polymerization (ATRP) technique with the bio-inspired polydopamine (PDA) chemistry. By manipulating the auto-oxidative polymerization of dopamine, uniform PDA layers were deposited on the surfaces and pore walls of ordered mesoporous silicas (OMSs), thereby promoting the immobilization of ATRP initiators. Poly(glycidyl methacrylate) (PGMA) brushes were then grown from the OMSs by using the ICAR ATRP technique. The evolution of the mesoporous silica/polymer hybrids during synthesis, in terms of morphology, structure, surface and porous properties, was detailed. And, parameters influencing the controlled growth of polymer chains in the ICAR ATRP system were studied. Taking advantage of the abundant epoxy groups in the PGMA platform, post-functionalization of the mesoporous silica/polymer hybrids by the covalent attachment of macrocyclic ligands for the adsorptive separation of lithium isotopes was realized. Adsorption behavior of the functionalized hybrids toward lithium ions was fully investigated, highlighting the good selectivity, and effects of temperature, solvent and counter ions. The ability for lithium isotope separation was evaluated. A higher separation factor could be obtained in systems with softer counter anions and lower polarity solvents. More importantly, due to the versatility of the ICAR ATRP technique, combined with the non-surface specific PDA chemistry, the methodology established in this work would provide new opportunities for the preparation of advanced organic-inorganic porous hybrids for broadened applications.

  11. Hybrid membranes PVA/silicon for use in fuel cells; Membranas hibridas de PVA/silica para aplicacao em celula a combustivel

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Liz C.V. de; Almeida, Raquel D. de; Gomes, Ailton de S. [Universidade Federal do Rio de Janeiro - UFRJ, Instituto de Macromoleculas Professora Eloisa Mano - IMA, RJ (Brazil)], e-mail: lizcontino@ima.ufrj.br; Ramos Filho, Florencio G. de [Centro Universitario Estadual da Zona Oeste - UEZO, Rio de Janeiro, RJ (Brazil)

    2011-07-01

    Hybrids organic-inorganic membranes PVA-silica have been prepared using sol-gel process in situ with the objective of study the influence of inorganic particles incorporation on the water uptake, pervaporation and proton conductivity of PVA membranes. The silica was constituted of mercaptopropyltrimethoxysilane (MPTMS) with or without the mixture with the tetra ethoxysilane (TEOS). The hybrids membranes were oxidated to convert the -SH groups in -SO{sub 3}H groups, becoming them proton conducting. The hybrids membranes not oxidated showed lesser water uptake and pervaporated material, probably, due to the formation of crosslink that restricted the swell of the PVA membrane. The protonic conductivity of the hybrid membranes after the oxidation was up to 26 times bigger than of the membrane not oxidated. (author)

  12. Selective microemulsion liquid chromatography analysis of dopamine receptor antagonist LE300 and its N-methyl metabolite in mouse sera by using a monolithic silica column.

    Science.gov (United States)

    Al-Majed, Abdulrhman A; Hefnawy, Mohamed M; Mohammed, Mostafa S; Attia, Sabry M; Lehmann, Jochen

    2015-05-01

    A highly selective, sensitive, and rapid microemulsion liquid chromatography (MELC) method was developed and validated for the simultaneous determination of a novel type of dopamine receptor antagonist LE300 and its N-methyl metabolite in mouse sera. LE300, its N-methyl metabolite, and pindolol (an internal standard) were detected using excitation and emission wavelengths of 275 and 340 nm, respectively. HPLC analysis by using a monolithic column was performed by directly injecting the sample after appropriate dilution with the microemulsion mobile phase. The chromatographic behaviour of these compounds was studied to demonstrate their chromatographic efficiency, retention, and peak symmetry. The MELC method was validated for its specificity, linearity, accuracy, precision, robustness and stability. An experimental design was used during validation to evaluate method robustness. The calibration curves in serum showed excellent linearity (r=0.997) over concentrations ranging from 10 to 400 ngmL(-1) for LE300 and 15 to 500 ngmL(-1) for its N-methyl metabolite. The mean relative standard deviation (RSD) of the results of inter- and intra-day precision and accuracy of LE300 and its N-methyl metabolite were ≤5%. The overall recoveries of LE300 and its N-methyl metabolite from mouse sera were in the range 97.9-101.5% with %RSD ranging from 0.98% to 3.63%, which were in line with ICH guidelines. The assay was successfully applied in a pharmacokinetic study.

  13. Sequential extraction of inorganic arsenic compounds and methyl arsenate in human urine using mixed-mode monolithic silica spin column coupled with gas chromatography-mass spectrometry.

    Science.gov (United States)

    Namera, Akira; Takeuchi, Akito; Saito, Takeshi; Miyazaki, Shota; Oikawa, Hiroshi; Saruwatari, Tatsuro; Nagao, Masataka

    2012-09-01

    A sequential analytical method was developed for the detection of arsenite, arsenate, and methylarsenate in human urine by gas chromatography-mass spectrometry (GC-MS). The combination of a derivatization of trivalent arsenic compounds by 2,3-dithio-1-propanol (British antilewisite; BAL) and a reduction of pentavalent arsenic compounds (arsenate and methylarsenate) were accomplished to carry out the analysis of arsenic compounds in urine. The arsenic derivatives obtained using BAL were extracted in a stepwise manner using a monolithic spin column and analyzed by GC-MS. A linear curve was observed for concentrations of arsenic compounds of 2.0 to 200 ng/mL, where the correlation coefficients of calibration curves were greater than 0.996 (for a signal-to-noise (S/N) ratio >10). The detection limits were 1 ng/mL (S/N > 3). Recoveries of the targets in urine were in the range 91.9-106.5%, and RSDs of the intra- and interday assay for urine samples containing 5, 50, and 150 ng/mL of arsenic compounds varied between 2.95 and 13.4%. The results from real samples obtained from a patient suspected of having ingested As containing medications using this proposed method were in good agreement with those obtained using high-performance liquid chromatography with inductively coupled plasma mass spectrometry.

  14. Organic-inorganic crosslinked and hybrid membranes derived from sulfonated poly(arylene ether sulfone)/silica via sol-gel process

    Science.gov (United States)

    Feng, Shaoguang; Shang, Yuming; Wang, Yingzi; Xie, Xiaofeng; Mathur, V. K.; Xu, Jingming

    A series of covalently crosslinkable organic-inorganic hybrid membranes have been prepared from sulfonated poly(arylene ether sulfone) (SPAES) with pendant propenyl moiety and various amounts of vinyl substituted silica via sol-gel process which are then thermally crosslinked in the presence of benzoyl peroxide (BPO) initiator. The obtained membranes are characterized in terms of oxidative stability, thermal property, ion exchange capacity (IEC), water uptake, swelling ratio in methanol aqueous solution, proton conductivity, and methanol permeability coefficient. The results indicate that the oxidative stability and thermal stability of the hybrid membranes are improved. Moreover, introduction of silica reduces the water uptake and methanol swelling of membranes. The swelling ratio of membranes in 2 mol L -1 methanol aqueous solution at 80 °C slowly decreases from 26 to 19% with the increase of SiO 2 content from 0 to 12 wt.%. Furthermore, with the increase in silica content, the methanol permeability coefficient of the hybrid membranes decreases at first and then increases. When the silica content reaches 8 wt.%, the methanol permeability coefficient is at the minimum of 6.02 × 10 -7 cm 2 s -1, a 2.64-fold decrease compared with that of the pristine SPAES membrane. Moreover, the proton conductivity is found to be at about 95% of that of pristine polymer at that silica content.

  15. Organic-inorganic crosslinked and hybrid membranes derived from sulfonated poly(arylene ether sulfone)/silica via sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Shaoguang; Shang, Yuming; Wang, Yingzi; Xie, Xiaofeng; Xu, Jingming [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Mathur, V.K. [Department of Chemical Engineering, University of New Hampshire, NH 03824 (United States)

    2010-05-01

    A series of covalently crosslinkable organic-inorganic hybrid membranes have been prepared from sulfonated poly(arylene ether sulfone) (SPAES) with pendant propenyl moiety and various amounts of vinyl substituted silica via sol-gel process which are then thermally crosslinked in the presence of benzoyl peroxide (BPO) initiator. The obtained membranes are characterized in terms of oxidative stability, thermal property, ion exchange capacity (IEC), water uptake, swelling ratio in methanol aqueous solution, proton conductivity, and methanol permeability coefficient. The results indicate that the oxidative stability and thermal stability of the hybrid membranes are improved. Moreover, introduction of silica reduces the water uptake and methanol swelling of membranes. The swelling ratio of membranes in 2 mol L{sup -1} methanol aqueous solution at 80 C slowly decreases from 26 to 19% with the increase of SiO{sub 2} content from 0 to 12 wt.%. Furthermore, with the increase in silica content, the methanol permeability coefficient of the hybrid membranes decreases at first and then increases. When the silica content reaches 8 wt.%, the methanol permeability coefficient is at the minimum of 6.02 x 10{sup -7} cm{sup 2} s{sup -1}, a 2.64-fold decrease compared with that of the pristine SPAES membrane. Moreover, the proton conductivity is found to be at about 95% of that of pristine polymer at that silica content. (author)

  16. Silica nanoparticle-based dual imaging colloidal hybrids: cancer cell imaging and biodistribution

    Directory of Open Access Journals (Sweden)

    Lee H

    2015-08-01

    Full Text Available Haisung Lee,1 Dongkyung Sung,2 Jinhoon Kim,3 Byung-Tae Kim,3 Tuntun Wang,4 Seong Soo A An,5 Soo-Won Seo,6 Dong Kee Yi4 1Molecular Diagnostics, In Vitro Diagnostics Unit, New Business Division, SK Telecom, 2Department of Life Sciences, Graduate School of Korea University, 3Interdisciplinary Graduate Program of Biomedical Engineering, School of Medicine, Sungkyunkwan University, Samsung Medical Center, 4Department of Chemistry, Myongji University, Seoul, 5Department of Bionanotechnology, Gachon Medical Research Institute, Gachon University, Seongnam, 6Medical Device Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, Republic of Korea Abstract: In this study, fluorescent dye-conjugated magnetic resonance (MR imaging agents were investigated in T mode. Gadolinium-conjugated silica nanoparticles were successfully synthesized for both MR imaging and fluorescence diagnostics. Polyamine and polycarboxyl functional groups were modified chemically on the surface of the silica nanoparticles for efficient conjugation of gadolinium ions. The derived gadolinium-conjugated silica nanoparticles were investigated by zeta potential analysis, transmission electron microscopy, inductively coupled plasma mass spectrometry, and energy dispersive x-ray spectroscopy. MR equipment was used to investigate their use as contrast-enhancing agents in T1 mode under a 9.4 T magnetic field. In addition, we tracked the distribution of the gadolinium-conjugated nanoparticles in both lung cancer cells and organs in mice. Keywords: dual bioimaging, MR imaging, silica colloid, T1 contrast imaging, nanohybrid

  17. Hybrid Mesoporous Silicas and Microporous POSS-Based Frameworks Incorporating Evaporation-Induced Self-Assembly

    Directory of Open Access Journals (Sweden)

    Jheng-Guang Li

    2015-06-01

    Full Text Available We fabricated a series of mesoporous silicas and mesoporous organosilicates with hierarchical porosity through evaporation-induced self-assembly using Pluronic F127 as a template in this study. We could tailor the mesophase of each mesoporous silica sample by varying the weight ratio of its two silica sources: tetraethyl orthosilicate (TEOS and triethoxysilane hydrosilylated octavinyl polyhedral oligomeric silsesquioxane (OV-POSS-SILY. The mesophases ranged from an ordered body-centered cubic (bcc structure (TEOS alone to ordered face-centered cubic (fcc structure (10 and 20 wt.% of OV-POSS-SILY and finally to disordered spherical pores (≥30 wt.% of OV-POSS-SILY. We used small-angle X-ray scattering (SAXS and transmission electron microscopy (TEM to study the transformations of these mesophases, while N2 isotherm sorption curves revealed the porosities of these mesoporous silicate samples. Moreover, 29Si CP/MAS solid state nuclear magnetic resonance spectroscopy allowed us to analyze the compositions of the POSS-containing silicate frameworks. Such functional mesoporous silica samples incorporating microporous POSS building units have potential applications in various systems, including optical and electronic devices.

  18. Hybrid Mesoporous Silicas and Microporous POSS-Based Frameworks Incorporating Evaporation-Induced Self-Assembly

    Science.gov (United States)

    Li, Jheng-Guang; Chu, Wei-Cheng; Kuo, Shiao-Wei

    2015-01-01

    We fabricated a series of mesoporous silicas and mesoporous organosilicates with hierarchical porosity through evaporation-induced self-assembly using Pluronic F127 as a template in this study. We could tailor the mesophase of each mesoporous silica sample by varying the weight ratio of its two silica sources: tetraethyl orthosilicate (TEOS) and triethoxysilane hydrosilylated octavinyl polyhedral oligomeric silsesquioxane (OV-POSS-SILY). The mesophases ranged from an ordered body-centered cubic (bcc) structure (TEOS alone) to ordered face-centered cubic (fcc) structure (10 and 20 wt.% of OV-POSS-SILY) and finally to disordered spherical pores (≥30 wt.% of OV-POSS-SILY). We used small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) to study the transformations of these mesophases, while N2 isotherm sorption curves revealed the porosities of these mesoporous silicate samples. Moreover, 29Si CP/MAS solid state nuclear magnetic resonance spectroscopy allowed us to analyze the compositions of the POSS-containing silicate frameworks. Such functional mesoporous silica samples incorporating microporous POSS building units have potential applications in various systems, including optical and electronic devices.

  19. Investigation of interphase effects in silica-polystyrene nanocomposites based on a hybrid molecular-dynamics-finite-element simulation framework

    Science.gov (United States)

    Pfaller, Sebastian; Possart, Gunnar; Steinmann, Paul; Rahimi, Mohammad; Müller-Plathe, Florian; Böhm, Michael C.

    2016-05-01

    A recently developed hybrid method is employed to study the mechanical behavior of silica-polystyrene nanocomposites (NCs) under uniaxial elongation. The hybrid method couples a particle domain to a continuum domain. The region of physical interest, i.e., the interphase around a nanoparticle (NP), is treated at molecular resolution, while the surrounding elastic continuum is handled with a finite-element approach. In the present paper we analyze the polymer behavior in the neighborhood of one or two nanoparticle(s) at molecular resolution. The coarse-grained hybrid method allows us to simulate a large polymer matrix region surrounding the nanoparticles. We consider NCs with dilute concentration of NPs embedded in an atactic polystyrene matrix formed by 300 chains with 200 monomer beads. The overall orientation of polymer segments relative to the deformation direction is determined in the neighborhood of the nanoparticle to investigate the polymer response to this perturbation. Calculations of strainlike quantities give insight into the deformation behavior of a system with two NPs and show that the applied strain and the nanoparticle distance have significant influence on the deformation behavior. Finally, we investigate to what extent a continuum-based description may account for the specific effects occurring in the interphase between the polymer matrix and the NPs.

  20. Synthesis of Bioactive Chlorogenic Acid-Silica Hybrid Materials via the Sol-Gel Route and Evaluation of Their Biocompatibility.

    Science.gov (United States)

    Catauro, Michelina; Pacifico, Severina

    2017-07-21

    Natural phenol compounds are gaining a great deal of attention because of their potential use as prophylactic and therapeutic agents in many diseases, as well as in applied science for their preventing role in oxidation deterioration. With the aim to synthetize new phenol-based materials, the sol-gel method was used to embed different content of the phenolic antioxidant chlorogenic acid (CGA) within silica matrices to obtain organic-inorganic hybrid materials. Fourier transform infrared (FTIR) measurements were used to characterize the prepared materials. The new materials were screened for their bioactivity and antioxidant potential. To this latter purpose, direct DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azinobis-(3-ethylbenzothiazolin-6-sulfonic acid) methods were applied: radical scavenging capability appeared strongly dependent on the phenol amount in investigated hybrids, and became pronounced, mainly toward the ABTS radical cation, when materials with CGA content equal to 15 wt% and 20 wt% were analyzed. The in vitro biocompatibility of the synthetized materials was estimated by using the MTT assay towards fibroblast NIH 3T3 cells, human keratinocyte HaCaT cells, and the neuroblastoma SH-SY5Y cell line. As cell viability and morphology of tested cell lines seemed to be unaffected by new materials, the attenuated total reflectance (ATR)-FTIR method was applied to deeply measure the effects of the hybrids in the three different cell lines.

  1. Synthesis of co-polymer-grafted gum karaya and silica hybrid organic–inorganic hydrogel nanocomposite for the highly effective removal of methylene blue

    CSIR Research Space (South Africa)

    Mittal, H

    2015-11-01

    Full Text Available Engineering Journal Vol. 279, 166–179 Synthesis of co-polymer-grafted gum karaya and silica hybrid organic–inorganic hydrogel nanocomposite for the highly effective removal of methylene blue Hemant Mittal ⇑ , Arjun Maity ⇑ , Suprakas Sinha Ray...

  2. Aqueous Hybrids of Silica Nanoparticles and Hydrophobically Associating Hydrolyzed Polyacrylamide Used for EOR in High-Temperature and High-Salinity Reservoirs

    Directory of Open Access Journals (Sweden)

    Dingwei Zhu

    2014-06-01

    Full Text Available Water-soluble polymers are known to be used in chemically enhanced oil recovery (EOR processes, but their applications are limited in high-temperature and high-salinity oil reservoirs because of their inherent poor salt tolerance and weak thermal stability. Hydrophobic association of partially hydrolyzed polyacryamide (HAHPAM complexed with silica nanoparticles to prepare nano-hybrids is reported in this work. The rheological and enhanced oil recovery (EOR properties of such hybrids were studied in comparison with HAHPAM under simulated high-temperature and high-salinity oil reservoir conditions (T: 85 °C; total dissolved solids: 32,868 mg∙L−1; [Ca2+] + [Mg2+]: 873 mg∙L−1. It was found that the apparent viscosity and elastic modulus of HAHPAM solutions increased with addition of silica nanoparticles, and HAHPAM/silica hybrids exhibit better shear resistance and long-term thermal stability than HAHPAM in synthetic brine. Moreover, core flooding tests show that HAHPAM/silica hybrid has a higher oil recovery factor than HAHPAM solution.

  3. Functionalized Polysilsesquioxane-Based Hybrid Silica Solid Amine Sorbents for the Regenerative Removal of CO2 from Air.

    Science.gov (United States)

    Abhilash, Kochukunju Adisser Saraladevi; Deepthi, Thomas; Sadhana, Retnakumari Amma; Benny, K George

    2015-08-19

    Functionalized polysilsesquioxane-based hybrid silica materials are presented as solid amine sorbents for direct CO2 capture from air. The sorbent was synthesized from amine and vinyl functionalized alkoxysilanes by a simple, energy efficient, and cost-effective co-condensation method. The material, containing bound amine functionalities, was found to have a selective CO2 capturing capacity of 1.68 mmol/g from atmospheric air with an adsorption half time of 50 min. This material also showed a maximum adsorption capacity of 2.28 mmol/g in pure CO2 and 1.92 mmol/g in 10% CO2. Desorption started at a temperature as low as 60 °C, and complete desorption occurred at 80 °C. The sorbent exhibited high recycling ability, and 100 cycles of adsorption/desorption were demonstrated in pure CO2 and 50 cycles in ambient air without any loss in efficiency.

  4. Hydrophilic solid-phase extraction of melamine with ampholine-modified hybrid organic-inorganic silica material.

    Science.gov (United States)

    Wang, Tingting; Zhu, Yiming; Ma, Junfeng; Xuan, Rongrong; Gao, Haoqi; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2015-01-01

    In this work, an ampholine-functionalized hybrid organic-inorganic silica sorbent was successfully used to extract melamine from a milk formula sample by a hydrophilic interaction solid-phase extraction protocol. Primary factors affecting the extraction efficiency of the material such as extraction solvent, elution solvent, sample loading volume, and elution volume have been thoroughly optimized. Under the optimized hydrophilic solid-phase extraction conditions, the recoveries of melamine spiked in milk formula samples ranged from 86.2 to 101.8% with relative standard deviations of 4.1-9.4% (n = 3). The limit of detection (S/N = 3) was 0.32 μg/g. The adsorption capacity toward melamine was 30 μg of melamine per grams of sorbent. Due to its simplicity, rapidity and cost effectiveness, the newly developed hydrophilic solid-phase extraction method should provide a promising tool for daily monitoring of doped melamine in milk formula.

  5. Ability of dynamic holography in self-assembled hybrid nanostructured silica films for all-optical switching and multiplexing

    Science.gov (United States)

    Telbiz, German; Bugaychuk, Svitlana; Leonenko, Eugen; Derzhypolska, Liudmyla; Gnatovskyy, Vladimir; Pryadko, Igor

    2015-04-01

    The sol-gel method has been employed in the fabrication of easily processable mesostructured films consisting of a nonionic surfactant and silica as the inorganic component. The ability of the occluded Pluronic P123 mesostructures to solubilize guest molecules made these films ideal host matrices for organic dyes and molecular assemblies, possessing substantial nonlinear susceptibilities. These films were explored for use as the photonic layer in all-optical time-to-space converters and proved successful at increasing the optical response of the intercalated dyes to a point that would make these composite films applicable for use as the photonic layer. Recording of a dynamical grating in a single-pulse regime has been obtained. Since the dynamical grating exhibits the fast relaxation time (up to 10 ns), the nonlinear mechanism represents an electronic excitation of the photosensitive molecules. As far as the dye molecules are distributed in nanoporous silica, a model of `gas of molecular dye' may be rightly used in order to consider nonlinear optical properties in the nanostructured hybrid films. We suppose that further improvement of the nonlinear optical nanomaterials may follow on the way to embed additional inclusions, which will not promote the heat accumulation in the host matrix and will lead to effective dissipation of the heat energy.

  6. Design and Cellular Fate of Bioinspired Au-Ag Nanoshells@Hybrid Silica Nanoparticles.

    Science.gov (United States)

    Soulé, Samantha; Bulteau, Anne-Laure; Faucher, Stéphane; Haye, Bernard; Aimé, Carole; Allouche, Joachim; Dupin, Jean-Charles; Lespes, Gaëtane; Coradin, Thibaud; Martinez, Hervé

    2016-10-04

    Silica-coated gold-silver alloy nanoshells were obtained via a bioinspired approach using gelatin and poly-l-lysine (PLL) as biotemplates for the interfacial condensation of sodium silicate solutions. X-ray photoelectron spectroscopy was used as an efficient tool for the in-depth and complete characterization of the chemical features of nanoparticles during the whole synthetic process. Cytotoxicity assays using HaCaT cells evidenced the detrimental effect of the gelatin nanocoating and significant induction of late apoptosis after silicification. In contrast, PLL-modified nanoparticles had less biological impact that was further improved by the silica layer, and uptake rates of up to 50% of those of the initial particles could be achieved. These results are discussed considering the effect of nanosurface confinement of the biopolymers on their chemical and biological reactivity.

  7. Synthesis of hybrid inorganic/organic nitric oxide-releasing silica nanoparticles for biomedical applications

    Science.gov (United States)

    Carpenter, Alexis Wells

    Nitric oxide (NO) is an endogenously produced free radical involved in a number of physiological processes. Thus, much research has focused on developing scaffolds that store and deliver exogenous NO. Herein, the synthesis of N-diazeniumdiolate-modified silica nanoparticles of various physical and chemical properties for biomedical applications is presented. To further develop NO-releasing silica particles for antimicrobial applications, a reverse microemulsion synthesis was designed to achieve nanoparticles of distinct sizes and similar NO release characteristics. Decreasing scaffold size resulted in improved bactericidal activity against Pseudomonas aeruginosa. Confocal microscopy revealed that the improved efficacy resulted from faster particle-bacterium association kinetics. To broaden the therapeutic potential of NO-releasing silica particles, strategies to tune NO release characteristics were evaluated. Initially, surface hydrophobicity and NO release kinetics were tuned by grafting hydrocarbon- and fluorocarbon-based silanes onto the surface of N-diazeniumdiolate-modified particles. The addition of fluorocarbons resulted in a 10x increase in the NO release half-life. The addition of short-chained hydrocarbons to the particle surface increased their stability in hydrophobic electrospun polyurethanes. Although NO release kinetics were longer than that of unmodified particles, durations were still limited to resin composites yielded antibacterial NO-releasing dental restorative materials. A 3-log reduction in viable adhered Streptococcus mutans was observed with the MOM-Pip/NO-doped composites compared to undoped controls. The greater chemical flexibility of macromolecular scaffolds is a major advantage over LMW NO donors as it allows for the incorporation of multiple functionalities onto a single scaffold. To demonstrate this advantage, dual functional particles were synthesized by covalently binding quaternary ammonium (QA) functionalities to the surface of

  8. Mixed Pyridine-phenol Boron Complex Encapsulated in Polymer/Silica Hybrid Sol-gel Matrix

    Institute of Scientific and Technical Information of China (English)

    DONG Wei; TANG Jun; WANG Yue

    2008-01-01

    A novel pyridine-phenol boron complex[(dppy)BF]was encapsulated into polymer/silica composite matrix by sol-gel process.UV-Vis absorption spectra show that this process can control the aggregation structure of complex(dppy)BF.The results of photoluminescence of(dppy)BF in sol-gel composite film indicate that both fluorescence intensity and photostability are markedly increased using this method compared with other methods,which increases the practical significance of such composite film.

  9. The effect of high temperature sol-gel polymerization parameters on the microstructure and properties of hydrophobic phenol-formaldehyde/silica hybrid aerogels.

    Science.gov (United States)

    Seraji, Mohamad Mehdi; Sameri, Ghasem; Davarpanah, Jamal; Bahramian, Ahmad Reza

    2017-05-01

    Phenol-formaldehyde/silica hybrid aerogels with different degree of hydrophobicity were successfully synthesized via high temperature sol-gel polymerization. Tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) were used as precursor and co-precursor of the hydrophobic silica-based phase, respectively. The hydrolysis step of silica based sols were conducted by acid catalyzed reactions and HCl was used as hydrolysis catalyst. The chemical structure of prepared hybrid aerogels was characterized by Fourier Transform Infrared spectroscopy (FT-IR). The effect of MTES/TEOS proportion and catalyst content on the morphology and microstructure of samples were investigated by FE-SEM and C, Si mapping analysis. The acid catalyzed hydrolysis of TEOS and MTES sols leads to formation of a sol with primarily silica particles in the organic-inorganic hybrid sol and varying colloid growth mechanisms were occurred with change in MTES and HCl molar ratio. With the increasing of MTES content, the microstructure of samples changed from uniform colloidal network, core-shell structure to polymeric structure with a huge phase separation. The increasing of HCl mole fraction leads to smaller particle size. Moreover, the shrinkage of samples was decreased and water contact angles of the resulted aerogels were increased from 40 to 156.8° with the increases of MTES content.

  10. Ampholine-functionalized hybrid organic-inorganic silica material as sorbent for solid-phase extraction of acidic and basic compounds.

    Science.gov (United States)

    Wang, Tingting; Chen, Yihui; Ma, Junfeng; Chen, Mingliang; Nie, Chenggang; Hu, Minjie; Li, Ying; Jia, Zhijian; Fang, Jianghua; Gao, Haoqi

    2013-09-20

    A novel sorbent for solid-phase extraction (SPE) was synthesized by chemical immobilization of ampholine on hybrid organic-inorganic silica material. The ampholine-functionalized hybrid organic-inorganic silica sorbent is consisted of aliphatic amine groups, carboxyl groups and long carbon chains, allowing for extraction of both acidic and basic compounds. The retention properties of the developed sorbent were evaluated for 1-hydroxy-2-naphthoic acid (HNA), 1-naphthoic acid (NA), 3-hydroxybenzoic acid (HBA), benzoic acid (BA), sorbic acid (SA), vanillic aldehyde (VA), butyl 4-hydroxybenzoate (BHB), propyl 4-hydroxybenzoate (PHB), ethyl 4-hydroxybenzoate (EHB), and methyl 4-hydroxybenzoate (MHB). The results show that such a sorbent has three types of interaction, i.e., electrostatic interaction, hydrophobic interaction, and hydrogen bonding, exhibiting high extraction efficiency towards the compounds tested. The adsorption capacities of the analytes ranged from 0.61 to 6.54μgmg(-1). The reproducibility of the sorbent preparation was evaluated at three spiking concentration levels, with relative standard deviations (RSDs) of 1.0-10.5%. The recoveries of ten acidic and basic compounds spiked in beverage Coca-Cola(®) sample ranged from 82.5% to 98.2% with RSDs less than 5.8%. Under optimum conditions, the ampholine-functionalized hybrid organic-inorganic silica sorbent rendered higher extraction efficiency for acidic compounds than that of the commercially available ampholine-functionalized silica particles, and was comparable to that of the commercial Oasis WAX and Oasis WCX.

  11. Synthesis and characterization of polymer-silica hybrid latexes and sol-gel-derived films

    Science.gov (United States)

    Petcu, Cristian; Purcar, Violeta; Ianchiş, Raluca; Spătaru, Cătălin-Ilie; Ghiurea, Marius; Nicolae, Cristian Andi; Stroescu, Hermine; Atanase, Leonard-Ionuţ; Frone, Adriana Nicoleta; Trică, Bogdan; Donescu, Dan

    2016-12-01

    Sol-gel derived organic-inorganic hybrid systems were obtained by applying alkaline-catalyzed co-hydrolysis and copolycondensation reactions of tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), isobutyltriethoxysilane (IBTES), diethoxydimethylsilane (DMDES), and vinyltriethoxysilane (VTES), respectively, into a polymer latex functionalized with vinyltriethoxysilane (VTES). The properties of the latex hybrid materials were analyzed by FTIR, water contact angle, environmental scanning electron microscopy (ESEM), TEM and AFM analysis, respectively. FT-IR spectra confirmed that the chemical structures of the sol-gel derived organic-inorganic materials are changed as function of inorganic precursor and Sisbnd Osbnd Si networks are formed during the co-hydrolysis and copolycondensation reactions. The water contact angle on the sol-gel latex film containing TEOS + VTES increased to 135° ± 2 compared to 65° ± 5 for the blank latex, due VTES incorporation into latex material. TGA curves of hybrid sample modifies against neat polymer, the thermal stability being influenced by the presence of the inorganic partner. ESEM analysis showed that the latex hybrid films prepared with different inorganic precursors were formed and the Si-based polymers were distributed on the surface of the dried sol-gel hybrid films. TEM and AFM photos revealed that the latex emulsion morphology was modified due to the VTES incorporation into system.

  12. Silica-polyethylene glycol hybrids synthesized by sol-gel: Biocompatibility improvement of titanium implants by coating.

    Science.gov (United States)

    Catauro, M; Bollino, F; Papale, F; Ferrara, C; Mustarelli, P

    2015-10-01

    Although metallic implants are the most used in dental and orthopaedic fields, they can early fail due to low tissue tolerance or osseointegration ability. To overcome this drawback, functional coatings can be applied on the metallic surface to provide a firm fixation of the implants. The objective of the present study was twofold: to synthesize and to characterize silica/polyethylene glycol (PEG) hybrid materials using sol-gel technique and to investigate their capability to dip-coat titanium grade 4 (Ti-gr4) substrates to improve their biological properties. Various hybrid systems have been synthesized by changing the ratio between the organic and inorganic phases in order to study the influence of the polymer amount on the structure and, thus, on the properties of the coatings. Fourier transform infrared (FTIR) spectroscopy and solid state Nuclear Magnetic Resonance (NMR) allowed us to detect the formation of hydrogen bonds between the inorganic sol-gel matrix and the organic component. SEM analysis showed that high PEG content enables to obtain crack free-coating. Moreover, the effective improvement in biological properties of Ti-gr4 implants has been evaluated by performing in vitro tests. The bioactivity of the hybrid coatings has been showed by the hydroxyapatite formation on the surface of SiO2/PEG coated Ti-gr4 substrates after soaking in a simulated body fluid and the lack of cytotoxicity by the WST-8 Assay. The results showed that the coated substrates are more bioactive and biocompatible than the uncoated ones and that the bioactivity is not significantly affected by PEG amount whereas its addition makes the films more biocompatible.

  13. The accelerating effect of chitosan-silica hybrid dressing materials on the early phase of wound healing.

    Science.gov (United States)

    Park, Ji-Ung; Jung, Hyun-Do; Song, Eun-Ho; Choi, Tae-Hyun; Kim, Hyoun-Ee; Song, Juha; Kim, Sukwha

    2017-10-01

    Commercialized dressing materials with or without silver have played a passive role in early-phase wound healing, protecting the skin defects from infections, absorbing exudate, and preventing dehydration. Chitosan (CTS)-based sponges have been developed in pure or hybrid forms for accelerating wound healing, but their wound-healing capabilities have not been extensively compared with widely used commercial dressing materials, providing limited information in a practical aspect. In this study, we have developed CTS-silica (CTS-Si) hybrid sponges with water absorption, flexibility, and mechanical behavior similar to those of CTS sponges. In vitro and in vivo tests were performed to compare the CTS-Si sponges with three commercial dressing materials [gauze, polyurethane (PU), and silver-containing hydrofiber (HF-Ag)] in addition to CTS sponges. Both in vitro and in vivo tests showed that CTS-Si sponges promoted fibroblast proliferation, leading to accelerated collagen synthesis, whereas the CTS sponges did not exhibit significant differences in fibroblast proliferation and collagen synthesis from gauze, PU, and HF-Ag sponges. In case of CTS-Si, the inflammatory cells were actively recruited to the wound by the influence of the released silicon ions from CTS-Si sponges, which, in return, led to an enhanced secretion of growth factors, particularly TGF-β during the early stage. The higher level of TGF-β likely improved the proliferation of fibroblasts, and as a result, collagen synthesis by fibroblasts became remarkably productive, thereby increasing collagen density at the wound site. Therefore, the CTS-Si hybrid sponges have considerable potential as a wound-dressing material for accelerating wound healing. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1828-1839, 2017. © 2016 Wiley Periodicals, Inc.

  14. Inorganic-organic hybrids based on poly (ε-Caprolactone and silica oxide and characterization by relaxometry applying low-field NMR

    Directory of Open Access Journals (Sweden)

    Mariana Sato de Souza de Bustamante Monteiro

    2012-12-01

    Full Text Available Poly (ε-caprolactone (PCL based hybrids containing different amounts of modified (Aerosil® R972 and unmodified (Aerosil® A200 silica oxide were prepared employing the solution method, using chloroform. The relationships of the amount of nanofillers, organic coating, molecular structure and intermolecular interaction of the hybrid materials were investigated mainly using low-field nuclear magnetic resonance (NMR. The NMR analyses involved the hydrogen spin-lattice relaxation time (T1H and hydrogen spin-lattice relaxation time in the rotating frame (T1ρH. The spin-lattice relaxation time measurements revealed that the PCL/silica oxide hybrids were heterogeneous, meaning their components were well dispersed. X-ray diffraction (XRD, differential scanning calorimetry (DSC and thermogravimetric analysis (TGA were also employed. The DSC data showed that all the materials had lower crystallization temperature (Tc and melting temperature (Tm, so the crystallinity degree of the PCL decreased in the hybrids. The TGA analysis demonstrated that the addition of modified and unmodified silica oxide does not cause considerable changes to PCL's thermal stability, since no significant variations in the maximum temperature (Tmax were observed in relation to the neat polymer.

  15. Design of interpenetrated networks of mesostructured hybrid silica and nonconductive poly(vinylidene fluoride)-cohexafluoropropylene (PVdF-HFP) polymer for proton exchange membrane fuel cell applications.

    Science.gov (United States)

    Pereira, Franck; Chan, Alida; Vallé, Karine; Palmas, Pascal; Bigarré, Janick; Belleville, Philippe; Sanchez, Clément

    2011-05-02

    Organic-inorganic hybrid membranes of poly(vinylidene fluoride)-cohexafluoropropylene (PVdF-HFP) and mesostructured silica containing sulfonic acid groups were synthesized by using the sol-gel process. These hybrid membranes were prepared by in situ co-condensation of tetraethoxysilane and an organically modified silane (ormosil) by a self-assembly route using organic surfactants as templates for tuning the architecture of the hybrid organosilica component. In this paper, we describe the elaboration and characterization of hybrid membranes all the way from the precursor solution to the evaluation of the fuel cell performances. These hybrid materials were extensively characterized by using NMR and IR spectroscopy, electron microscopy, or impedance spectroscopy so as to determinate their physicochemical and electrochemical properties. Even though the ion-exchange capacity (IEC) was quite weak, the first fuel cell tests performed with these hybrid membranes show promising results relative to optimized Nafion 112 thanks to great water management of the silica inside the hydrophobic polymer.

  16. Fabrication and characterization of stable superhydrophobic fluorinated-polyacrylate/silica hybrid coating

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kunquan; Zeng, Xingrong, E-mail: psxrzeng@gmail.com; Li, Hongqiang; Lai, Xuejun

    2014-04-01

    Graphical abstract: - Highlights: • The superhydrophobic PFA/SiO{sub 2} coating was successfully fabricated by spraying. • The synthesized PFA latex showed core–shell structure and good dispersion. • The PFA/SiO{sub 2} coating showed good resistance to acid and base, weather and heat. • The superhydrophobic coating could be fabricated on various substrates. - Abstract: The core–shell fluorinated-polyacrylate (PFA) emulsion was synthesized through emulsion polymerization method and the superhydrophobic PFA/SiO{sub 2} hybrid coating was successfully fabricated on the slide glass by spraying the mixture of PFA emulsion and hydrophobic SiO{sub 2} particles using ethanol as cosolvent. The PFA emulsion was characterized by Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), water contact angle (WCA), transmission electron microscopy (TEM), and the effects of SiO{sub 2} content on the wetting behavior and surface morphology of PFA/SiO{sub 2} hybrid coating were investigated. To evaluate the stability of the hybrid coating, the acid and base resistance, weatherability and thermal stability were also studied. Results showed that the obtained PFA latex exhibited a core–shell structure with a particle size of 134.1 nm and a narrow polydispersity of 0.03. With the increase of dodecafluoroheptyl methacrylate (DFMA) content in the latex shell from 0 wt% to 31.8 wt%, the WCA of the PFA film enlarged from 85° to 104°, indicating that the introduction of fluorinated monomer was effective in reducing the surface energy. By adding different amount of SiO{sub 2} particles, the surface morphology and wetting behavior of the PFA/SiO{sub 2} hybrid coatings could be controlled. When the mass ratio of SiO{sub 2} to PFA emulsion was 0.2, the surface roughness (Rq) increased to 173.6 nm and the wetting behavior of the surface became superhydrophobic with a WCA of 153°, resulted from the corporation of low surface energy and the binary nano

  17. Fabrication and characterization of stable superhydrophobic fluorinated-polyacrylate/silica hybrid coating

    Science.gov (United States)

    Li, Kunquan; Zeng, Xingrong; Li, Hongqiang; Lai, Xuejun

    2014-04-01

    The core-shell fluorinated-polyacrylate (PFA) emulsion was synthesized through emulsion polymerization method and the superhydrophobic PFA/SiO2 hybrid coating was successfully fabricated on the slide glass by spraying the mixture of PFA emulsion and hydrophobic SiO2 particles using ethanol as cosolvent. The PFA emulsion was characterized by Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), water contact angle (WCA), transmission electron microscopy (TEM), and the effects of SiO2 content on the wetting behavior and surface morphology of PFA/SiO2 hybrid coating were investigated. To evaluate the stability of the hybrid coating, the acid and base resistance, weatherability and thermal stability were also studied. Results showed that the obtained PFA latex exhibited a core-shell structure with a particle size of 134.1 nm and a narrow polydispersity of 0.03. With the increase of dodecafluoroheptyl methacrylate (DFMA) content in the latex shell from 0 wt% to 31.8 wt%, the WCA of the PFA film enlarged from 85° to 104°, indicating that the introduction of fluorinated monomer was effective in reducing the surface energy. By adding different amount of SiO2 particles, the surface morphology and wetting behavior of the PFA/SiO2 hybrid coatings could be controlled. When the mass ratio of SiO2 to PFA emulsion was 0.2, the surface roughness (Rq) increased to 173.6 nm and the wetting behavior of the surface became superhydrophobic with a WCA of 153°, resulted from the corporation of low surface energy and the binary nano/microstructure on the surface. The as-prepared PFA/SiO2 hybrid coating showed good acid and base corrosion resistance, and it could keep superhydrophobicity after being heated at 250 °C for 2 h or exposed to ambient atmosphere for more than 3 months. Additionally, the superhydrophobic PFA/SiO2 hybrid coating could be applied to various substrates through spraying. This was a green and eco-friendly method in fabricating stable

  18. Increased thermal conductivity monolithic zeolite structures

    Science.gov (United States)

    Klett, James; Klett, Lynn; Kaufman, Jonathan

    2008-11-25

    A monolith comprises a zeolite, a thermally conductive carbon, and a binder. The zeolite is included in the form of beads, pellets, powders and mixtures thereof. The thermally conductive carbon can be carbon nano-fibers, diamond or graphite which provide thermal conductivities in excess of about 100 W/mK to more than 1,000 W/mK. A method of preparing a zeolite monolith includes the steps of mixing a zeolite dispersion in an aqueous colloidal silica binder with a dispersion of carbon nano-fibers in water followed by dehydration and curing of the binder is given.

  19. DNA-Hybrid-Gated Photothermal Mesoporous Silica Nanoparticles for NIR-Responsive and Aptamer-Targeted Drug Delivery.

    Science.gov (United States)

    Zhang, Yuanxin; Hou, Zhiyao; Ge, Yakun; Deng, Kerong; Liu, Bei; Li, Xuejiao; Li, Quanshun; Cheng, Ziyong; Ma, Ping'an; Li, Chunxia; Lin, Jun

    2015-09-23

    Near-infrared light is an attractive stimulus due to its noninvasive and deep tissue penetration. Particularly, NIR light is utilized for cancer thermotherapy and on-demand release of drugs by the disruption of the delivery carriers. Here we have prepared a novel NIR-responsive DNA-hybrid-gated nanocarrier based on mesoporous silica-coated Cu1.8S nanoparticles. Cu1.8S nanoparticles, possessing high photothermal conversion efficiency under a 980 nm laser, were chosen as photothermal agents. The mesoporous silica structure could be used for drug storage/delivery and modified with aptamer-modified GC-rich DNA-helix as gatekeepers, drug vectors, and targeting ligand. Simultaneously, the as-produced photothermal effect caused denaturation of DNA double strands, which triggered the drug release of the DNA-helix-loaded hydrophilic drug doxorubicin and mesopore-loaded hydrophobic drug curcumin, resulting in a synergistic therapeutic effect. The Cu1.8S@mSiO2 nanocomposites endocytosed by cancer cells through the aptamer-mediated mode are able to generate rational release of doxorubicin/curcumin under NIR irradiation, strongly enhancing the synergistic growth-inhibitory effect of curcumin against doxorubicin in MCF-7 cells, which is associated with a strong mitochondrial-mediated cell apoptosis progression. The underlying mechanism of apoptosis showed a strong synergistic inhibitory effect both on the expression of Bcl-2, Bcl-xL, Mcl-1, and upregulated caspase 3/9 activity and on the expression level of Bak and Bax. Therefore, Cu1.8S@mSiO2 with efficient synergistic therapeutic efficiency is a potential multifunctional cancer therapy nanoplatform.

  20. Determination of Thallium(I by Hybrid Mesoporous Silica (SBA-15 Modified Electrode

    Directory of Open Access Journals (Sweden)

    Geeta Rani

    2016-01-01

    Full Text Available Chemically modified mesoporous silica material (SBA-15 was used for the construction of Tl(I selective carbon paste electrode. The best response was found with the electrode containing 10% modifier as electrode material. The electrode has a lower detection limit of 6.0 × 10−9 M in a working concentration range of 1.0 × 10−8–1.0 × 10−1 M. The selectivity coefficient calculated by match potential method (MPM shows the high selectivity of electrode towards Tl(I over other tested ions. The electrode was successfully applied as an indicator electrode for the titration of 0.01 M TlNO3 solution with standards EDTA solution and for sequential titration of mixture of different anions.

  1. Facile room temperature deposition of gold nanoparticle-ionic liquid hybrid film on silica substrate

    Science.gov (United States)

    Krishnamurthy, S.; Reddy, D. Harikishore Kumar; Sankar, G.; Yun, Yeoung-Sang

    2017-01-01

    This work presents facile synthesis of gold nanoparticle (Au NP)-ionic liquid hybrid film of synthesis, and even coating on Si (111) substrate. XRD, XPS, and XAS spectral data confirm the presence of Au(0) while EXAFS data indicated the presence of small particles or incomplete surface species. Cross-sectional analysis using FE-SEM and edge length measurement using AFM showed that the film thickness is ca 10 nm.

  2. Novel Silica-Based Hybrid Adsorbents: Lead(II Adsorption Isotherms

    Directory of Open Access Journals (Sweden)

    Junsheng Liu

    2013-01-01

    Full Text Available Water pollution caused by the lead(II from the spent liquor has caught much attention. The research from the theoretical model to application fundaments is of vital importance. In this study, lead(II adsorption isotherms are investigated using a series of hybrid membranes containing mercapto groups (–SH groups as the hybrid adsorbents. To determine the best fitting equation, the experimental data were analyzed using six two-parameter isotherm equations (i.e., Langmuir, Freundlich, Dubinin-Radushkevich (D-R, Temkin, Harkins-Jura, and Halsey isotherm models. It was found that the lead(II adsorption on these samples followed the Freundlich, Dubinin-Radushkevich (D-R, and Halsey isotherm models. Moreover, the mean free energy of adsorption was calculated using Dubinin-Radushkevich (D-R isotherm model and it was confirmed that the adsorption process was physical in nature. These findings are very meaningful in the removal of lead(II ions from water using the hybrid membranes as adsorbents.

  3. Successful entrapment of carbon dots within flexible free-standing transparent mesoporous organic-inorganic silica hybrid films for photonic applications

    Science.gov (United States)

    Vassilakopoulou, Anastasia; Georgakilas, Vasilios; Vainos, Nikolaos; Koutselas, Ioannis

    2017-04-01

    The effective entrapment of Carbon dots (CDs) into a polymer-silica hybrid matrix, formed as free standing transparent flexible films, is presented. The composite's synthesis, characterization, device application and properties -mechanical, thermal and optical- are being provided and discussed. CDs of 3 nm mean size with strong photoluminescence are embedded into a silica matrix during the sol-gel procedure, using tetraethyl orthosilicate as the precursor and F127 triblock copolymer as the structure directing agent under acidic conditions. The final hybrid nanostructure forms free standing transparent films that show high flexibility and long term stable CDs luminescence indicating the protective character of the hybrid matrix. It is crucial that the photoluminescence of the hybrid's CDs is not seriously affected after thermal treatment at 550 °C for 30 min. Moreover, the herein reported hybrid is demonstrated to be suitable for the fabrication of advanced photonic structures using soft lithography processes due to its low shrinkage and distortion upon drying, both attributable to its porosity. Finally, it is reported that addition of F127 ethanolic solution in aqueous solution of CDs induces a blue-shift of their photoluminescence.

  4. Monoliths in Bioprocess Technology

    Directory of Open Access Journals (Sweden)

    Vignesh Rajamanickam

    2015-04-01

    Full Text Available Monolithic columns are a special type of chromatography column, which can be used for the purification of different biomolecules. They have become popular due to their high mass transfer properties and short purification times. Several articles have already discussed monolith manufacturing, as well as monolith characteristics. In contrast, this review focuses on the applied aspect of monoliths and discusses the most relevant biomolecules that can be successfully purified by them. We describe success stories for viruses, nucleic acids and proteins and compare them to conventional purification methods. Furthermore, the advantages of monolithic columns over particle-based resins, as well as the limitations of monoliths are discussed. With a compilation of commercially available monolithic columns, this review aims at serving as a ‘yellow pages’ for bioprocess engineers who face the challenge of purifying a certain biomolecule using monoliths.

  5. Poly(ethylene oxide)-silica hybrids entrapping sensitive dyes for biomedical optical pH sensors: Molecular dynamics and optical response

    Science.gov (United States)

    Fabbri, Paola; Pilati, Francesco; Rovati, Luigi; McKenzie, Ruel; Mijovic, Jovan

    2011-06-01

    Polymer-silica hybrid nanocomposites prepared by sol-gel process based on triethoxisilane-terminated poly(ethylene oxide) chains and tetraethoxysilane as silica precursor, doped with organic pH sensitive dyes, have been prepared and their suitability for use as sensors coupled with plastic optic fibers has been evaluated. Sensors were prepared by immobilizing a drop of the hybrid materials onto the tip of a multi-mode poly(methyl methacrylate) optical fiber. The performance of the optical sensor in terms of sensitivity and response time was tested in different experimental conditions, and was found to be markedly higher than analogous sensors present on the market. The very fast kinetic of the hybrid's optical response was supported by studies performed at the molecular level by broadband dielectric relaxation spectroscopy (DRS), investigated over a wide range of frequency and temperature, showing that poly(ethylene oxide) chains maintain their dynamics even when covalently bonded to silica domains, which decrease the self-association interactions and promote motions of polymer chain segments. Due to the fast response kinetic observed, these pH optical sensors result suitable for the fast-detection of biomedical parameters, i.e. fast esophageous pH-metry.

  6. The Influence of New Hydrophobic Silica Nanoparticles on the Surface Properties of the Films Obtained from Bilayer Hybrids

    Science.gov (United States)

    Petcu, Cristian; Purcar, Violeta; Spătaru, Cătălin-Ilie; Alexandrescu, Elvira; Şomoghi, Raluca; Trică, Bogdan; Niţu, Sabina Georgiana; Panaitescu, Denis Mihaela; Donescu, Dan; Jecu, Maria-Luiza

    2017-01-01

    Ultra-hydrophobic bilayer coatings on a glass surface were fabricated by sol–gel process using hexadecyltrimethoxysilane (C16TMS) and tetramethoxysilane (TMOS) (1:4 molar ratio) as precursors. After coating, silica nanoparticles (SiO2 NPs) functionalized with different mono-alkoxy derivatives (methoxytrimethylsilane, TMeMS; ethoxydimethylvinylsilane, DMeVES; ethoxydimethylphenylsilane, DMePhES; and methoxydimethyloctylsilane, DMeC8MS) were added, assuring the microscale roughness on the glass surface. Influences of the functionalized SiO2 NPs and surface morphology on the hydrophobicity of the hybrid films were discussed. The successful functionalization of SiO2 NPs with hydrophobic alkyl groups were confirmed by Fourier transform infrared spectroscopy (FTIR). The thermal stability of hydrophobic SiO2 NPs showed that the degradation of the alkyl groups takes place in the 200–400 °C range. Bilayer coating with C16TMS/TMOS and SiO2 NPs modified with alkoxysilane substituted with C8 alkyl chain (SiO2 NP-C8) has micro/nano structure. Hydrophobicity of functionalized SiO2 NPs-C8 and its higher degree of nanometer-scale roughness gave rise to ultra-hydrophobicity performance for bilayer coating C16TMS/TMOS + SiO2 NPs-C8 (145°), compared to other similar hybrid structures. Our synthesis method for the functionalization of SiO2 NPs is useful for the modification of surface polarity and roughness.

  7. The Influence of New Hydrophobic Silica Nanoparticles on the Surface Properties of the Films Obtained from Bilayer Hybrids

    Directory of Open Access Journals (Sweden)

    Cristian Petcu

    2017-02-01

    Full Text Available Ultra-hydrophobic bilayer coatings on a glass surface were fabricated by sol–gel process using hexadecyltrimethoxysilane (C16TMS and tetramethoxysilane (TMOS (1:4 molar ratio as precursors. After coating, silica nanoparticles (SiO2 NPs functionalized with different mono-alkoxy derivatives (methoxytrimethylsilane, TMeMS; ethoxydimethylvinylsilane, DMeVES; ethoxydimethylphenylsilane, DMePhES; and methoxydimethyloctylsilane, DMeC8MS were added, assuring the microscale roughness on the glass surface. Influences of the functionalized SiO2 NPs and surface morphology on the hydrophobicity of the hybrid films were discussed. The successful functionalization of SiO2 NPs with hydrophobic alkyl groups were confirmed by Fourier transform infrared spectroscopy (FTIR. The thermal stability of hydrophobic SiO2 NPs showed that the degradation of the alkyl groups takes place in the 200–400 °C range. Bilayer coating with C16TMS/TMOS and SiO2 NPs modified with alkoxysilane substituted with C8 alkyl chain (SiO2 NP-C8 has micro/nano structure. Hydrophobicity of functionalized SiO2 NPs-C8 and its higher degree of nanometer-scale roughness gave rise to ultra-hydrophobicity performance for bilayer coating C16TMS/TMOS + SiO2 NPs-C8 (145°, compared to other similar hybrid structures. Our synthesis method for the functionalization of SiO2 NPs is useful for the modification of surface polarity and roughness.

  8. Particle size analyses of porous silica and hybrid silica chromatographic support particles. Comparison of flow/hyperlayer field-flow fractionation with scanning electron microscopy, electrical sensing zone, and static light scattering.

    Science.gov (United States)

    Xu, Yuehong

    2008-05-16

    Porous silica and hybrid silica chromatographic support particles having particle diameters ranging approximately from 1 microm to 15 microm have been characterized by flow/hyperlayer field-flow fractionation (FFF). The particle size accuracy has been improved significantly in this work by a second-order polynomial calibration. Very good agreement between the FFF data and scanning electron microscopic (SEM) results has been achieved. The effects of particle porosity, pore sizes, and particle sizes on the particle size accuracy in electrical sensing zone (ESZ) analyses have been discussed. It has been demonstrated by computer simulation and experimental measurements that false peaks can be generated in certain particle size regions when the static light scattering (SLS) technique is applied to tightly distributed spherical chromatographic support particles.

  9. Luminescent hybrid materials based on covalent attachment of Eu(III)-tris(bipyridinedicarboxylate) in the mesoporous silica host MCM-41.

    Science.gov (United States)

    Ilibi, Maturi; de Queiroz, Thiago Branquinho; Ren, Jinjun; De Cola, Luisa; de Camargo, Andrea Simone Stucchi; Eckert, Hellmut

    2014-06-14

    A luminescent inorganic-organic hybrid material was synthesized by covalent immobilization of a europium bipyridine carboxylate complex on the inner pore walls of the mesoporous silica host MCM-41 using the grafting method. Guest-host binding was achieved through double functionalization of the host surface with organosilane reagents (trimethylsilyl, TMS, and aminopropyltriethoxysilane, APTES) followed by reaction of the active amino sites of the APTES residue with the ligand 2,2'-bipyridyl-6,6'-dicarboxylic acid. Addition of EuCl3 solution dissolved in ethanol results in the formation of an immobilized complex having the probable formula Eu(L)x(3 ≥ x ≥ 1)(H2O)y, whose detailed photophysical properties were investigated. In the final step, an additional 2,2'-bipyridine-6 monocarboxylic acid ligand was added in an attempt to complete the coordination sphere of the rare earth ion. Each of the synthesis steps was monitored by (1)H, (13)C, and (29)Si solid state NMR spectroscopies, allowing for a quantitative assessment of the progress of the reaction and the influence of the paramagnetic species on the spectra. Based on these data and additional characterizations by chemical analysis, thermogravimetric analysis (TGA), N2 sorption, X-ray diffraction and FT-IR spectroscopy, a comprehensive quantitative picture of the covalent binding and complexation process was developed.

  10. In vitro cytotoxicity of fluorescent silica nanoparticles hybridized with aggregation-induced emission luminogens for living cell imaging.

    Science.gov (United States)

    Xia, Yun; Li, Min; Peng, Tao; Zhang, Weijie; Xiong, Jun; Hu, Qinggang; Song, Zifang; Zheng, Qichang

    2013-01-07

    Fluorescent silica nanoparticles (FSNPs) can provide high-intensity and photostable fluorescent signals as a probe for biomedical analysis. In this study, FSNPs hybridized with aggregation-induced emission (AIE) luminogens (namely FSNP-SD) were successfully fabricated by a surfactant-free sol-gel method. The FSNP-SD were spherical, monodisperse and uniform in size, with an average diameter of approximately 100 nm, and emitted strong fluorescence at the peak of 490 nm. The FSNP-SD selectively stained the cytoplasmic regions and were distributed in the cytoplasm. Moreover, they can stay inside cells, enabling the tacking of cells over a long period of time. The intracellular vesicles and multinucleated cells were increase gradually with the rise of FSNP-SD concentration. Both cell viability and survival only lost less than 20% when the cells were exposed to the high concentration of 100 μg/mL FSNP-SD. Additionally, the cell apoptosis and intracellular ROS assay indicated that FSNP-SD had no significant toxic effects at the maximum working concentration of 80 μg/mL. This study demonstrated that the FSNP-SD are promising biocompatible fluorescent probes for living cell imaging.

  11. In Vitro Cytotoxicity of Fluorescent Silica Nanoparticles Hybridized with Aggregation-Induced Emission Luminogens for Living Cell Imaging

    Directory of Open Access Journals (Sweden)

    Yun Xia

    2013-01-01

    Full Text Available Fluorescent silica nanoparticles (FSNPs can provide high-intensity and photostable fluorescent signals as a probe for biomedical analysis. In this study, FSNPs hybridized with aggregation-induced emission (AIE luminogens (namely FSNP-SD were successfully fabricated by a surfactant-free sol-gel method. The FSNP-SD were spherical, monodisperse and uniform in size, with an average diameter of approximately 100 nm, and emitted strong fluorescence at the peak of 490 nm. The FSNP-SD selectively stained the cytoplasmic regions and were distributed in the cytoplasm. Moreover, they can stay inside cells, enabling the tacking of cells over a long period of time. The intracellular vesicles and multinucleated cells were increase gradually with the rise of FSNP-SD concentration. Both cell viability and survival only lost less than 20% when the cells were exposed to the high concentration of 100 μg/mL FSNP-SD. Additionally, the cell apoptosis and intracellular ROS assay indicated that FSNP-SD had no significant toxic effects at the maximum working concentration of 80 μg/mL. This study demonstrated that the FSNP-SD are promising biocompatible fluorescent probes for living cell imaging.

  12. Computational and experimental determinations of the UV adsorption of polyvinylsilsesquioxane-silica and titanium dioxide hybrids.

    Science.gov (United States)

    Wang, Haiyan; Lin, Derong; Wang, Di; Hu, Lijiang; Huang, Yudong; Liu, Li; Loy, Douglas A

    2014-01-01

    Sunscreens that absorb UV light without photodegradation could reduce skin cancer. Polyvinyl silsesquioxanes are known to have greater thermal and photochemical stability than organic compounds, such as those in sunscreens. This paper evaluates the UV transparency of vinyl silsesquioxanes (VS) and its hybrids with SiO2(VSTE) and TiO2(VSTT) experimentally and computationally. Based on films of VS prepared by sol-gel polymerization, using benzoyl peroxide as an initiator, vinyltrimethoxysilane (VMS) formulated oligomer through thermal curing. Similarly, VSTE films were prepared from VMS and 5-25 wt-% tetraethoxysilane (TEOS) and VSTT films were prepared from VMS and 5-25 wt-% titanium tetrabutoxide (TTB). Experimental average transparencies of the modified films were found to be about 9-14% between 280-320 nm, 67-73% between 320-350nm, and 86-89% between 350-400nm. Computation of the band gap was absorption edges for the hybrids in excellent agreement with experimental data. VS, VSTE and VSTT showed good absorption in UV-C and UV-B range, but absorbed virtually no UV-A. Addition of SiO2 or TiO2 does not improve UV-B absorption, but on the opposite increases transparency of thin films to UV. This increase was validated with molecular simulations. Results show computational design can predict better sunscreens and reduce the effort of creating sunscreens that are capable of absorbing more UV-B and UV-A.

  13. Carboxymethyl Cellulose-Grafted Mesoporous Silica Hybrid Nanogels for Enhanced Cellular Uptake and Release of Curcumin

    Directory of Open Access Journals (Sweden)

    Neha Tiwari

    2017-02-01

    Full Text Available Mesoporous silica nanoparticles (MSNs with ordered pore structure have been synthesized and used as carriers for the anticancer drug curcumin. MSNs were functionalized with amine groups and further attached with carboxymethyl cellulose (CMC using 1-ethyl-3-(3-dimethylaminopropyl-carbodiimide (EDC coupling chemistry, which increased the hydrophilicity and biocompatibility of MSNs. The functionalized MSNs (MSN-NH2 and MSN-CMC were characterized using Scanning Electron Microscopy (SEM, Transmission Electron Microscopy (TEM, Dynamic Light Scattering (DLS, N2 adsorption, X-Ray Diffraction (XRD, Thermo Gravimetric Analysis (TGA and Fourier Transform Infrared Spectroscopy (FT-IR. The in vitro release of curcumin from the –NH2 and CMC functionalized MSNs (MSN-cur-NH2 and MSN-cur-CMC was performed in 0.5% aqueous solution of sodium lauryl sulphate (SLS. The effect of CMC functionalization of MSNs towards cellular uptake was studied in the human breast cancer cell line MDA-MB-231 and was compared with that of MSN-NH2 and free curcumin (cur. Both MSN-NH2 and MSN-CMC showed good biocompatibility with the breast cancer cell line. The MTT assay study revealed that curcumin-loaded MSN-cur-CMC showed better uptake as compared to curcumin-loaded MSN-cur-NH2. Free curcumin was used as a control and was shown to have much less internalization as compared to the curcumin-loaded functionalized MSNs due to poor bioavailability. Fluorescence microscopy was used to localize the fluorescent drug curcumin inside the cells. The work demonstrates that CMC-functionalized MSNs can be used as potential carriers for loading and release of hydrophobic drugs that otherwise cannot be used effectively in their free form for cancer therapy.

  14. Silica/quercetin sol-gel hybrids as antioxidant dental implant materials

    Science.gov (United States)

    Catauro, Michelina; Papale, Ferdinando; Bollino, Flavia; Piccolella, Simona; Marciano, Sabina; Nocera, Paola; Pacifico, Severina

    2015-06-01

    The development of biomaterials with intrinsic antioxidant properties could represent a valuable strategy for preventing the onset of peri-implant diseases. In this context, quercetin, a naturally occurring flavonoid, has been entrapped at different weight percentages in a silica-based inorganic material by a sol-gel route. The establishment of hydrogen bond interactions between the flavonol and the solid matrix was ascertained by Fourier transform infrared spectroscopy. This technique also evidenced changes in the stretching frequencies of the quercetin dienonic moiety, suggesting that the formation of a secondary product occurs. Scanning electron microscopy was applied to detect the morphology of the synthesized materials. Their bioactivity was shown by the formation of a hydroxyapatite layer on sample surface soaked in a fluid that simulates the composition of human blood plasma. When the potential release of flavonol was determined by liquid chromatography coupled with ultraviolet and electrospray ionization tandem mass spectrometry techniques, the eluates displayed a retention time that was 0.5 min less than quercetin. Collision-activated dissociation mass spectrometry and untraviolet-visible spectroscopy were in accordance with the release of a quercetin derivative. The antiradical properties of the investigated systems were evaluated by DPPH and ABTS methods, whereas the 2,7-dichlorofluorescein diacetate assay highlighted their ability to inhibit the H2O2-induced intracellular production of reactive oxygen species in NIH-3T3 mouse fibroblast cells. Data obtained, along with data gathered from the MTT cytotoxicity test, revealed that the materials that entrapped the highest amount of quercetin showed notable antioxidant effectiveness.

  15. A new precursor for the immobilization of enzymes inside sol-gel-derived hybrid silica nanocomposites containing polysaccharides.

    Science.gov (United States)

    Shchipunov, Yurii A; Karpenko, Tat'yana Yu; Bakunina, Irina Yu; Burtseva, Yuliya V; Zvyagintseva, Tat'yana N

    2004-01-30

    Tetrakis(2-hydroxyethyl) orthosilicate (THEOS) introduced by Hoffmann et al. (J. Phys. Chem. B., 106 (2002) 1528) was first used to prepare hybrid nanocomposites containing various polysaccharides and immobilize enzymes in these materials. Two different types of O-glycoside hydrolyses (EC3.2.1), 1-->3-beta-D-glucanase LIV from marine mollusk Spisula sacchalinensis and alpha-D-galactosidase from marine bacterium Pseudoalteromonas sp. KMM 701, were taken for the immobilization. To reveal whether the polysaccharide inside the hybrid material influences the enzyme entrapment and functioning, negatively charged xanthan, cationic derivative of hydroxyethylcellulose and uncharged locust bean gum were examined. The mechanical properties of these nanocomposites were characterized by a dynamic rheology and their structure by a scanning electron microscopy. It was found that 1-->3-beta-D-glucanase was usually immobilized without the loss of its activity, while the alpha-D-galactosidase activity in the immobilized state depended on the polysaccharide type of material. An important point is that the amount of immobilized enzymes was small, comparable to their content in the living cells. It was shown by the scanning electron microscopy that the hybrid nanocomposites are sufficiently porous that allows the enzymatic substrates and products to diffuse from an external aqueous solution to the enzymes, whereas protein molecules were immobilized firmly and not easily washed out of the silica matrix. A sharp increase of the enzyme lifetime (more than a hundred times) was observed after the immobilization. As established, the efficient entrapment of enzymes is caused by few advantages of new precursor over the currently used TEOS and TMOS: (i) organic solvents and catalysts are not needed owing to the complete solubility of THEOS in water and the catalytic effect of polysaccharides on the sol-gel processes; (ii) the entrapment of enzymes can be performed at any pH which is suitable

  16. Electrochemical immunosensor for ethinylestradiol using diazonium salt grafting onto silver nanoparticles-silica-graphene oxide hybrids.

    Science.gov (United States)

    Cincotto, Fernando H; Martínez-García, Gonzalo; Yáñez-Sedeño, Paloma; Canevari, Thiago C; Machado, S A S; Pingarrón, José M

    2016-01-15

    This work describes the preparation of an electrochemical immunosensor for ethinylestradiol (EE2) based on grafting of diazonium salt of 4-aminobenzoic acid onto a glassy carbon electrode modified with silver nanoparticles/SiO2/graphene oxide hybrid followed by covalent binding of anti-ethinylestradiol (anti-EE2) to activated carboxyl groups. A competitive immunoassay was developed for the determination of the hormone using peroxidase-labeled ethinylestradiol (HRP-EE2) and measurement of the amperometric response at -200mV in the presence of hydroquinone (HQ) as redox mediator. The calibration curve for EE2 exhibited a linear range between 0.1 and 50ng/mL (r(2)=0.996), with a detection limit of 65pg/mL. Interference studies with other hormones related with EE2 revealed the practical specificity of the developed method for the analyte. A good reproducibility, with RSD=4.5% (n=10) was also observed. The operating stability of a single bioelectrode modified with anti-EE2 was maintained at least for 15 days when it was stored at 4°C under humid conditions between measurements. The developed immunosensor was applied to the analysis of spiked urine with good results.

  17. Kinetics of Coloration in Photochromic Tungsten(VI) Oxide/Silicon Oxycarbide/Silica Hybrid Xerogel: Insight into Cation Self-diffusion Mechanisms.

    Science.gov (United States)

    Adachi, Kenta; Tokushige, Masataka; Omata, Kaoru; Yamazaki, Suzuko; Iwadate, Yoshiaki

    2016-06-08

    Silicon oxycarbide/silica composites with well-dispersed tungsten(VI) oxide (WO3) nanoparticles were obtained as transparent hybrid xerogels via an acid-catalyzed sol-gel process (hydrolysis/condensation polymerization) of 3-(triethoxysilyl)propyl methacrylate (TESPMA) and tetraethoxysilane (TEOS). The self-diffusion mechanism of alkali-metal cations and the kinetics of the photochromic coloration process in the WO3/TESPMA/TEOS hybrid xerogel systems have been systematically investigated. Under continuous UV illumination, a gradual color change (colorless → blue) corresponding to the reduction of W(6+) into W(5+) states in WO3 nanoparticles can be confirmed from the WO3/TESPMA/TEOS hybrid xerogels containing alkali-metal sulfates, although no coloration of the hybrid xerogel without alkali-metal sulfate was observed. The coloration behavior depended exclusively on a variety of alkali-metal cations present in the hybrid xerogel system. Furthermore, a detailed analysis of the self-diffusion mechanism confirmed that the alkali-metal cations electrostatically interact with a layer of unreacted silanol groups on the TESPMA/TEOS matrix surface, and subsequently pass through the interconnected pore network of the hybrid xerogel. More interestingly, in the context of an Arrhenius analysis, we found a good coincidence between the activation energies for alkali-metal cation self-diffusion and UV-induced coloration in the WO3/TESPMA/TEOS hybrid xerogel system containing the corresponding alkali-metal sulfate. It is experimentally obvious that the photochromic properties are dominated by the diffusion process of alkali-metal cations in the WO3/TESPMA/TEOS hybrid xerogel system. Such hybrid materials with cation-controlled photochromic properties will show promising prospects in applications demanding energy-efficient "smart windows" and "smart glasses".

  18. SnxTi1-xO2 solid-solution-nanoparticle embedded mesoporous silica (SBA-15) hybrid as an engineered photocatalyst with enhanced activity.

    Science.gov (United States)

    Srinivasan, N R; Bandyopadhyaya, Rajdip

    2016-01-01

    Synthesis of hybrids of a porous host-material (with well-dispersed embedded nanoparticles inside the pore), wherein each nanoparticle has precisely controlled properties (size and composition) poses a generic challenge. To this end, a new strategy is proposed to form SnxTi1-xO2 solid-solution-nanoparticles inside the pores of sphere-like mesoporous silica (SBA-15), with different percentages of Sn in the nanoparticle (varying from 5 to 50 at%), for enhanced photocatalysis. X-ray diffraction confirms the formation of solid-solution nanoparticles in the porous silica hybrid, while the location of nanoparticles and elemental composition are identified using electron microscopy. The hybrid with 5 at% of Sn (Sn0.05Ti0.95O2-sphere-like SBA-15) shows the maximum photocatalytic activity for degradation of rhodamine-B dye (first order rate constant for degradation, k = 1.86 h(-1)), compared to both pure TiO2-sphere-like SBA-15 (k = 1.38 h(-1)) or pure SnO2-sphere-like SBA-15 (k = 0.14 h(-1)) or other hybrids in this series. XPS and PL spectra suggest the formation of more oxygen vacancies during the replacement of Ti(4+) with Sn(4+). Electrochemical studies reveal that there is a reduction of charge transfer resistance from 910 kΩ cm(-2) for TiO2-sphere-like SBA-15, to 332 kΩ cm(-2) for Sn0.05Ti0.95O2-sphere-like SBA-15. These results imply that the enhancement in photocatalytic performance is as a result of delay in recombination of charge carriers. Therefore, the approach followed in the present work to form solid-solution nanoparticles inside a porous host without causing pore blockage, would be a promising route towards increasing reaction rates in catalytic applications of hybrid materials.

  19. Silica Supported Ceria Nanoparticles: A Hybrid Nanostructure To Increase Stability And Surface Reactivity Of Nano-crystalline Ceria

    Energy Technology Data Exchange (ETDEWEB)

    Munusamy, Prabhakaran; Sanghavi, Shail P.; Varga, Tamas; Thevuthasan, Suntharampillai

    2014-01-21

    The mixed oxidation state (3+/4+) of ceria nanoparticles of smaller sizes make them attractive materials for their catalytic antioxidant biological properties. However the unmodified smaller ceria nanoparticles are limited in their use due to particles agglomeration and reduced surface chemical reactivity in the solutions used to disperse the nanoparticles. This work describes an effort to stabilize small ceria nanoparticles, retaining their desired activity, on a larger stable silica support. The ceria nanoparticles attached to silica was synthesized by a solution synthesis technique in which the surface functional groups of silica nanoparticles were found to be essential for the formation of smaller ceria nanoparticles. The surface chemical and vibrational spectroscopy analysis revealed cerium–silicate (Ce-O-Si) covalent bond linkage between silica and cerium oxide nanoparticles. The colloidal properties (agglomerate particle size and suspension stability) of ceria attached to silica was significantly improved due to inherent physico-chemical characteristics of silica against random collision and gravitation settling as opposed to unmodified ceria nanoparticles in solution. The bio-catalytic activity of ceria nanoparticles in the 3+ oxidation state was not found to be limited by attachment to the silica support as measured by free radical scavenging activity in different biological media conditions.

  20. Eu3+/Sm3+ hybrids based with 8-hydroxybenz[de]anthracen-7-one organically modified mesoporous silica SBA-15/16

    Science.gov (United States)

    Gu, Yan-Jing; Yan, Bing

    2015-12-01

    A series of organic-inorganic hybrid materials were prepared by linking lanthanide (Eu3+, Sm3+) complexes to mesoporous SBA-15/SBA-16 through 8-hydroxybenz[de]anthracen-7-one modified silane (HBA-Si) as linker. The physical characterizations of these hybrids revealed that they all have high surface area, uniformity in mesostructure. The luminescence properties of these covalently bonded materials (denoted as Ln(HBA-SBA-15)3phen and Ln(HBA-SBA-16)3phen) were compared with ternary complexes (Ln(HBA)3phen) (Ln = Eu, Sm). Eu(HBA-SBA-15(16))3phen hybrids display better thermal stability, whose luminescent lifetimes and quantum efficiencies were matchable with those of Eu(HBA)3phen complex in spite of its much lower effective condensation of Eu3+ species. In addition, the luminescent performance of functionalized SBA-15 hybrids was more favorable than that of functionalized SBA-16 hybrids, revealing that SBA-15 was a better host material for lanthanide complex than mesoporous silica SBA-16.

  1. SYNTHESIS OF MESOPOROUS POLY(STYRENE-co-MALEIC ANHYDRIDE)/SILICA HYBRID MATERIALS VIA A NONSURFACTANT-TEMPLATED SOL-GEL PROCESS

    Institute of Scientific and Technical Information of China (English)

    Jie-bin Pang; Kun-yuan Qiu; Yen Wei

    2000-01-01

    Mesoporous poly(styrene-co-maleic anhydride)/silica hybrid materials have been prepared. The synthesis was achieved by the HCl-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS) and styrene-maleic anhydride copolymer in the presence of 3-aminopropyl triethoxysilane (APTES) as a coupling agent and citric acid as a nonsurfactant template or pore-forming agent, followed by ethanol extraction. Characterization results from nitrogen sorption isotherms and powder Xray diffraction indicate that polymer-modified mesoporous materials with large specific surface areas (e.g. 900 m2/g) and pore volumes (e.g. 0.6 cm3/g) could be prepared. As the citric acid concentration is increased, the specific surface areas, pore volumes and pore diameters of the hybrid materials increase.

  2. One-pot synthesis of silica-hybridized Ag{sub 2}S–CuS nanocomposites with tunable nonlinear optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Ann Mary, K.A. [School of Pure & Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Unnikrishnan, N.V., E-mail: nvu100@yahoo.com [School of Pure & Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Philip, Reji [Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India)

    2015-10-15

    Highlights: • Silica modified QDs of CuS and Ag{sub 2}S is developed at room temperature. • Formation of Ag{sub 2}S/CuS nanocomposites is confirmed from XRD and FFT of HRTEM images. • The concentration dependent growth of silica modified QDs is discussed. • Nonlinear absorption observed in ns excitations is dominated by SA and ESA. • Tuning of optical limiting efficiency is achieved with relative Ag{sub 2}S content. - Abstract: In the present work we report a simple, facile route developed for preparing silica hybridized copper sulfide and silver sulfide quantum dots at room temperature. By adjusting the concentration of the precursors, Ag{sub 2}S can form Ag{sub 2}S–CuS nanocomposites which are self regulated in one pot. Their crystalline, structural and optical properties have been investigated in detail, and the optical limiting nature is studied from fluence-dependent transmittance measurements employing short (5 ns) laser pulses at 532 nm. Ag{sub 2}S nanoparticles are found to have large third order nonlinear optical coefficients with a relatively lower optical limiting threshold of 1.7 J cm{sup −2}, while the nonlinearity of the nanocomposites is found to lie in between that of Ag{sub 2}S and CuS nanoparticles. These results suggest pathways for designing good quality optical limiters with tunable optical limiting efficiencies by varying the constituent nanocrystal compositions.

  3. Structural aspects and porosity features of nano-size high surface area alumina-silica mixed oxide catalyst generated through hybrid sol-gel route

    Energy Technology Data Exchange (ETDEWEB)

    Padmaja, P. [Ceramic Technology Division, Regional Research Laboratory (CSIR), Trivandrum 695019, Kerala (India)]. E-mail: padmavasudev@yahoo.com; Warrier, K.G.K. [Ceramic Technology Division, Regional Research Laboratory (CSIR), Trivandrum 695019, Kerala (India)]. E-mail: kgk_warrier@yahoo.com; Padmanabhan, M. [School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686560, Kerala (India); Wunderlich, W. [Graduate School of Engineering, Nagoya Institute of Technology, 466-8555 Nagoya (Japan); Berry, F.J. [Department of Chemistry, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Mortimer, M. [Department of Chemistry, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Creamer, N.J. [Department of Chemistry, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2006-01-10

    Alumina-silica mixed oxide nano-catalyst materials with compositions 83.6 wt.% Al{sub 2}O{sub 3}-16.4 wt.% SiO{sub 2} (3Al{sub 2}O{sub 3}.1SiO{sub 2}), 71.82 wt.% Al{sub 2}O{sub 3}-28.18 wt.% SiO{sub 2} (3Al{sub 2}O{sub 3}.2SiO{sub 2}), 62.84 wt.% Al{sub 2}O{sub 3}-37.16 wt.% SiO{sub 2} (3Al{sub 2}O{sub 3}.3SiO{sub 2}) and 56.03 wt.% Al{sub 2}O{sub 3}-43.97 wt.% SiO{sub 2} (3Al{sub 2}O{sub 3}.4SiO{sub 2}) have been prepared by a hybrid sol-gel technique using boehmite as the precursor for alumina and tetraethoxysilane as that for silica. The bonding characteristics and coordination features around Al and Si in the mixed oxide catalysts have been studied using FTIR and {sup 27}Al MAS NMR after calcination at 400 deg. C which is the temperature region where cross-condensation is seen to take place. A high BET specific surface area of 287 m{sup 2} g{sup -1} is obtained for 3Al{sub 2}O{sub 3}.1SiO{sub 2} mixed oxide composition. The porosity features are further established by BET adsorption isotherms and pore size distribution analysis. The temperature-programmed desorption studies showed more surface active sites for the silica-rich composition, suggesting enhanced catalytic potential. The TEM features of the mixed oxides showed a homogeneous distribution of alumina and silica phases with particle sizes in the nano-range. The low silica-containing mixed oxide showed a needle-like morphology with a high aspect ratio of 1:50 and {approx}10 nm particle size while the silica-rich composition had particle size in a wide range ({approx}20-75 nm)

  4. Immobilizing gold nanoparticles in mesoporous silica covered reduced graphene oxide: a hybrid material for cancer cell detection through hydrogen peroxide sensing.

    Science.gov (United States)

    Maji, Swarup Kumar; Sreejith, Sivaramapanicker; Mandal, Amal Kumar; Ma, Xing; Zhao, Yanli

    2014-08-27

    A new kind of two-dimensional (2-D) hybrid material (RGO-PMS@AuNPs), fabricated by the immobilization of ultrasmall gold nanoparticles (AuNPs, ∼3 nm) onto sandwich-like periodic mesopourous silica (PMS) coated reduced graphene oxide (RGO), was employed for both electrocatalytic application and cancer cell detection. The hybrid-based electrode sensor showed attractive electrochemical performance for sensitive and selective nonenzymatic detection of hydrogen peroxide (H2O2) in 0.1 M phosphate buffered saline, with wide linear detection range (0.5 μM to 50 mM), low detection limit (60 nM), and good sensitivity (39.2 μA mM(-1) cm(-2)), and without any interference by common interfering agents. In addition, the sensor exhibited a high capability for glucose sensing and H2O2 detection in human urine. More interestingly, the hybrid was found to be nontoxic, and the electrode sensor could sensitively detect a trace amount of H2O2 in a nanomolar level released from living tumor cells (HeLa and HepG2). Because the hybrid presents significant properties for the detection of bioactive species and certain cancerous cells by the synergistic effect from RGO, PMS, and AuNPs, it could be able to serve as a versatile platform for biosensing, bioanalysis, and biomedical applications.

  5. Experimental Results and Model Calculations of a Hybrid Adsorption-Compression Heat Pump Based on a Roots Compressor and Silica Gel-Water Sorption

    Energy Technology Data Exchange (ETDEWEB)

    Van der Pal, M.; De Boer, R.; Wemmers, A.K.; Smeding, S.F.; Veldhuis, J.B.J.; Lycklama a Nijeholt, J.A.

    2013-10-15

    Thermally driven sorption systems can provide significant energy savings, especially in industrial applications. The driving temperature for operation of such systems limits the operating window and can be a barrier for market-introduction. By adding a compressor, the sorption cycle can be run using lower waste heat temperatures. ECN has recently started the development of such a hybrid heat pump. The final goal is to develop a hybrid heat pump for upgrading lower (<100C) temperature industrial waste heat to above pinch temperatures. The paper presents the first measurements and model calculations of a hybrid heat pump system using a water-silica gel system combined with a Roots type compressor. From the measurements can be seen that the effect of the compressor is dependent on where in the cycle it is placed. When placed between the evaporator and the sorption reactor, it has a considerable larger effect compared to the compressor placed between the sorption reactor and the condenser. The latter hardly improves the performance compared to purely heat-driven operation. This shows the importance of studying the interaction between all components of the system. The model, which shows reasonable correlation with the measurements, could proof to be a valuable tool to determine the optimal hybrid heat pump configuration.

  6. Sensitive detection of influenza viruses with Europium nanoparticles on an epoxy silica sol-gel functionalized polycarbonate-polydimethylsiloxane hybrid microchip.

    Science.gov (United States)

    Liu, Jikun; Zhao, Jiangqin; Petrochenko, Peter; Zheng, Jiwen; Hewlett, Indira

    2016-12-15

    In an effort to develop new tools for diagnosing influenza in resource-limited settings, we fabricated a polycarbonate (PC)-polydimethylsiloxane (PDMS) hybrid microchip using a simple epoxy silica sol-gel coating/bonding method and employed it in sensitive detection of influenza virus with Europium nanoparticles (EuNPs). The incorporation of sol-gel material in device fabrication provided functionalized channel surfaces ready for covalent immobilization of primary antibodies and a strong bonding between PDMS substrates and PC supports without increasing background fluorescence. In microchip EuNP immunoassay (µENIA) of inactivated influenza viruses, replacing native PDMS microchips with hybrid microchips allowed the achievement of a 6-fold increase in signal-to-background ratio, a 12-fold and a 6-fold decreases in limit-of-detection (LOD) in influenza A and B tests respectively. Using influenza A samples with known titers, the LOD of influenza µENIA on hybrid microchips was determined to be ~10(4) TCID50 titer/mL and 10(3)-10(4) EID50 titer/mL. A comparison test indicated that the sensitivity of influenza µENIA enhanced using the hybrid microchips even surpassed that of a commercial laboratory influenza ELISA test. In addition to the sensitivity improvement, assay variation was clearly reduced when hybrid microchips instead of native PDMS microchips were used in the µENIA tests. Finally, infectious reference viruses and nasopharyngeal swab patient specimens were successfully tested using μENIA on hybrid microchip platforms, demonstrating the potential of this unique microchip nanoparticle assay in clinical diagnosis of influenza. Meanwhile, the tests showed the necessity of using nucleic acid confirmatory tests to clarify ambiguous test results obtained from prototype or developed point-of-care testing devices for influenza diagnosis.

  7. Bifunctional ferromagnetic Eu-Gd-Bi-codoped hybrid organo-silica red emitting phosphors synthesized by a modified Pechini sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Abo-Naf, S.M., E-mail: sm.abo-naf@nrc.sci.eg [Glass Research Department, National Research Centre (NRC), El-Buhouth Str., Dokki, 12622 Cairo (Egypt); Abdel-Hameed, S.A.M.; Marzouk, M.A. [Glass Research Department, National Research Centre (NRC), El-Buhouth Str., Dokki, 12622 Cairo (Egypt); Hamdy, Y.M. [Spectroscopy Department, National Research Centre (NRC), El-Buhouth Str., Dokki, 12622 Cairo (Egypt)

    2017-06-15

    Red phosphor, composed of Eu-Gd-Bi-codoped hybrid organo-silica glass, has been synthesized via a modified Pechini sol-gel process. The synthesized hybrid glass was analyzed with powder X-ray diffraction (XRD), differential thermal analysis coupled with thermogravimetry (DTA-TG) and Fourier transform infrared (FTIR) spectroscopy. XRD and DTA-TG confirmed its amorphous structure up to 1000 °C. Magnetic behavior of the produced phosphor was investigated using vibrating specimen magnetometer (VSM) and the obtained results revealed its unsaturated ferromagnetic behavior. Photoluminescence (PL) properties of the obtained phosphor have been investigated under near-UV excitation at 395 nm. The influence of calcination temperature on the PL intensity and its decay behavior as well as on the ferromagnetic characteristics has been studied to determine the optimal reaction temperature of the phosphor. The PL emission spectra show the characteristic emission bands of Eu{sup 3+} ions in the wavelength range from 580 to 700 nm. These emission spectra have been dominated by the electric dipole {sup 5}D{sub 0}→{sup 7}F{sub 2} transition of the Eu{sup 3+} peaked at 610–620 nm producing the red light emission of the phosphors. It was found that the phosphor performance, expressed by its PL intensity and life time, could be significantly improved by increasing of the heat treatment temperature up to 900 °C. Also, calcination at 900 °C for 6 h greatly increased both of the magnetization and retentivity, while decreased the coercivity value. The organic phenomenon of metal citrate-ethylene glycol chelation and its degradation by calcination were well followed by FTIR spectroscopy. The obtained results are promising and could afford a basis for designing of efficient red phosphors for displays, lighting and bifunctional biosensors for biomedical applications. - Highlights: • Eu-Gd-Bi-codoped hybrid organo-silica phosphor was synthesized by sol-gel method. • Inorganic Eu-Gd-Bi-silica

  8. Preparation of poly(γ-glutamic acid)/hydroxyapatite monolith via biomineralization for bone tissue engineering.

    Science.gov (United States)

    Park, Sung-Bin; Hasegawa, Urara; van der Vlies, André J; Sung, Moon-Hee; Uyama, Hiroshi

    2014-01-01

    A hybrid monolith of poly(γ-glutamic acid) and hydroxyapatite (PGA/HAp monolith) was prepared via biomineralization and used as a macroporous cell scaffold in bone tissue engineering. The PGA monolith having a bimodal pore size distribution was used as a substrate to induce biomineralization. The PGA/HAp monolith was obtained by immersing the PGA monolith in simulated body fluid. Pretreatment with CaCl2 enhanced the apatite-forming ability of the PGA monolith. Murine osteoblastic MC3T3-E1 cells efficiently attached and proliferated on the PGA/HAp monolith. MTT assay showed that both the PGA and PGA/HAp monolith did not have apparent cytotoxicity. Moreover, the PGA and PGA/HAp monoliths adsorbed bone morphogenetic protein-2 (BMP-2) by electrostatic interaction which was slowly released in the medium during cell culture. The PGA/HAp monolith enhanced BMP-2 induced alkaline phosphatase activity compared to the PGA monolith and a polystyrene culture plate. Thus, these PGA/HAp monoliths may have potential in bone tissue engineering.

  9. Hybrid molecularly imprinted poly(methacrylic acid-TRIM)-silica chemically modified with (3-glycidyloxypropyl)trimethoxysilane for the extraction of folic acid in aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Midori de Oliveira, Fernanda; Gava Segatelli, Mariana [Departamento de Química, Universidade Estadual de Londrina, Rod. Celso Garcia Cid, PR 445 Km 380, Campus Universitário, Londrina, PR CEP 86051-990 (Brazil); Tarley, César Ricardo Teixeira, E-mail: ctarleyquim@yahoo.com.br [Departamento de Química, Universidade Estadual de Londrina, Rod. Celso Garcia Cid, PR 445 Km 380, Campus Universitário, Londrina, PR CEP 86051-990 (Brazil); Instituto Nacional de Ciência e Tecnologia (INCT) de Bioanalítica, Universidade Estadual de Campinas (UNICAMP), Instituto de Química, Departamento de Química Analítica, Cidade Universitária Zeferino Vaz s/n, CEP 13083-970 Campinas, SP (Brazil)

    2016-02-01

    In the present study a hybrid molecularly imprinted poly(methacrylic acid-trimethylolpropane trimethacrylate)-silica (MIP) was synthesized and modified with (3-glycidyloxypropyl)trimethoxysilane (GPTMS) with posterior opening of epoxy ring to provide hydrophilic properties of material in the extraction of folic acid from aqueous medium. The chemical and structural aggregates of hybrid material were characterized by means of Fourier Transform Infrared (FT-IR), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Thermogravimetric analysis (TGA) and textural data. Selectivity data of MIP were compared to non-imprinted polymer (NIP) through competitive sorption studies in the presence of caffeine, paracetamol or 4-aminobenzamide yielding relative selectivity coefficients (k′) higher than one unit, thus confirming the selective character of MIP even in the presence of structurally smaller compounds than the folic acid. The lower hydrophobic sorption by bovine serum albumin (BSA) in the MIP as compared to unmodified MIP proves the hydrophilicity of polymer surface by using GPTMS with opening ring. Under acid medium (pH 1.5) the sorption of folic acid onto MIP from batch experiments was higher than the one achieved for NIP. Equilibrium sorption of folic acid was reached at 120 min for MIP, NIP and MIP without GPTMS and kinetic sorption data were well described by pseudo-second-order, Elovich and intraparticle diffusion models. Thus, these results indicate the existence of different binding energy sites in the polymers and a complex mechanism consisting of both surface sorption and intraparticle transport of folic acid within the pores of polymers. - Highlights: • The molecularly imprinted hybrid polymer showed high adsorption capacity for folic acid. • The molecularly imprinted hybrid polymer showed high selectivity for folic acid. • The molecularly imprinted hybrid polymer modified with GPTMS excludes higher amount of BSA.

  10. Atomic force microscopy indentation to determine mechanical property for polystyrene–silica core–shell hybrid particles with controlled shell thickness

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yang, E-mail: cy.jpu@126.com [School of Materials Science and Engineering, Changzhou University, Changzhou, Jiangsu 213164 (China); Qian, Cheng [School of Materials Science and Engineering, Changzhou University, Changzhou, Jiangsu 213164 (China); Miao, Naiming [School of Mechanical Engineering, Changzhou University, Changzhou, Jiangsu 213016 (China)

    2015-03-31

    The positively charged polystyrene (PS) particles with a size of ca. 200 nm were synthesized by soap-free polymerization. The PS cores were coated with silica shells of tunable thickness employing the modified Stöber method. The PS cores were removed by thermal decomposition at 500 °C, resulting in well-defined silica hollow spheres (10–30 nm in shell thickness). The elastic response of the as-synthesized samples was probed by an atomic force microscope (AFM). A point load was applied to the particle surface through a sharp AFM tip, and the force–displacement curves were recorded. Elastic moduli (E) for the PS particles (2.01 ± 0.70 GPa) and the core–shell structured hybrid particles were determined on the basis of Hertzian contact model. The calculated E values of composites exhibited a linear dependence on the silica shell thickness. While the shell thickness increased from ca. 10 to 15 and 20 nm, the E values of composites increased from 4.42 ± 0.27 to 5.88 ± 0.48 and 9.07 ± 0.94 GPa. For core–shell structured organic/inorganic composites, the E values of the hybrid particles were much lower than those of inorganic shells, while these values were much close to those of organic cores. Moreover, the moduli of elasticity of the composites appeared to be determined by the properties of the polymer cores, the species of inorganic shells and the thickness of shells. Besides, the inorganic shells enhanced the mechanical properties of the polymer cores. This work will provide essential experimental and theoretical basis for the design and application of core–shell structured organic/inorganic composite abrasives in chemical mechanical polishing/planarization. - Highlights: • The elastic moduli (E) of the PS/SiO{sub 2} hybrid particles were probed by AFM. • The E values of composites exhibited a linear dependence on the shell thickness. • The elasticity appeared to be determined by the properties of the organic cores. • The E values were affected

  11. Influence of the hybrid material size in silicon oxycarbide materials characteristics; Influencia del tamano del material hibrido en las caracteristicas de los oxicarburos de silicio obtenidos

    Energy Technology Data Exchange (ETDEWEB)

    Mazo, M. A.; Palencia, C.; Nistal, A.; Rubio, F.; Rubio, J.; Oteo, J. L.

    2012-11-01

    In this work has been investigated the influence of the TEOS/PDMS hybrid size during the pyrolysis process to obtain the related silicon oxycarbide glasses. Hybrids monolithic pieces (100 mm x 50 mm x 5 mm), were crushed (1 mm x 1 mm x 1 mm) and grounded in agate or attrition to 16 and 3 {mu}m, respectively. Then, they were pyrolyzed at 1100 degree centigrade to obtain silicon oxycarbide glasses (SiOC). These materials present structural and microstructural differences. The monolithic sample showed the highest %C into the silica network (34 %), and after grounding in agate mortar decreased to 26 %. However the attrition milled sample reached %C values similar to the monolithic (32 %). This agrees with FT-IR band at 880 cm-1 assigned to Si-C bonds formation and related to higher carbon content into silica network. The carbon free phase displays a domain size of 3.44 nm which increased to 3.66 nm for the attrition milled. This result is due to a higher graphitization degree. The SiOC monolithic sample morphology displays spherical interconnected particles with pores of 12 {mu}m. This morphology disappeared for the SiOC attrition milled sample, formed by irregular particles of 3 {mu}m. (Author) 38 refs.

  12. Synthesis and characterization of hierarchically porous metal, metal oxide, and carbon monoliths with highly ordered nanostructure

    Science.gov (United States)

    Grano, Amy Janine

    Hierarchically porous materials are of great interest in such applications as catalysis, separations, fuel cells, and advanced batteries. One such way of producing these materials is through the process of nanocasting, in which a sacrificial template is replicated and then removed to form a monolithic replica. This replica consists of mesopores, which can be ordered or disordered, and bicontinuous macropores, which allow flow throughout the length of the monolith. Hierarchically porous metal oxide and carbon monoliths with an ordered mesopores system are synthesized for the first time via nanocasting. These replicas were used as supports for the deposition of silver particles and the catalytic efficiency was evaluated. The ordered silica template used in producing these monoliths was also used for an in-situ TEM study involving metal nanocasting, and an observation of the destruction of the silica template during nanocasting made. Two new methods of removing the silica template were developed and applied to the synthesis of copper, nickel oxide, and zinc oxide monoliths. Finally, hollow fiber membrane monoliths were examined via x-ray tomography in an attempt to establish the presence of this structure throughout the monolith.

  13. Purge and trap with monolithic sorbent for gas chromatographic analysis of pesticides in honey.

    Science.gov (United States)

    Chienthavorn, Orapin; Dararuang, Kanittha; Sasook, Anupop; Ramnut, Narumol

    2012-01-01

    Polydivinylbenzene (P-DVB) and silica monolithic materials were synthesised in capillaries and then used to adsorb nine organonitrogen pesticides extracted from honey. After adsorption, each monolith-capillary was connected to a gas chromatograph (GC) with nitrogen-phosphorous detector (NPD). The silica monolith gave better peak shape and intensity than the P-DVB monolith. Formulation of silica monolith with tetramethoxysilane (TMOS) as a sole initiator provided better separation and higher peak intensity, compared to those with methyltrimethoxysilane (MTMS) and (3:1) TMOS/MTMS initiators. The optimum internal diameter and length of silica monolith-capillary were 0.25 mm and 5 cm, respectively. The purge and trap conditions were optimised by purging with nitrogen and heating the honey sample solution at 100 °C for 60 min. Recovery of the method was in a range of 84.95-99.71% and the detection limits of the pesticides determined by using GC-NPD and GC-mass spectrometric detector (MSD) ranged between 0.36-1.75 and 0.13-0.25 ng g(-1), respectively.

  14. Sol-gel encapsulation of binary Zn(II) compounds in silica nanoparticles. Structure-activity correlations in hybrid materials targeting Zn(II) antibacterial use.

    Science.gov (United States)

    Halevas, E; Nday, C M; Kaprara, E; Psycharis, V; Raptopoulou, C P; Jackson, G E; Litsardakis, G; Salifoglou, A

    2015-10-01

    In the emerging issue of enhanced multi-resistant properties in infectious pathogens, new nanomaterials with optimally efficient antibacterial activity and lower toxicity than other species attract considerable research interest. In an effort to develop such efficient antibacterials, we a) synthesized acid-catalyzed silica-gel matrices, b) evaluated the suitability of these matrices as potential carrier materials for controlled release of ZnSO4 and a new Zn(II) binary complex with a suitably designed well-defined Schiff base, and c) investigated structural and textural properties of the nanomaterials. Physicochemical characterization of the (empty-loaded) silica-nanoparticles led to an optimized material configuration linked to the delivery of the encapsulated antibacterial zinc load. Entrapment and drug release studies showed the competence of hybrid nanoparticles with respect to the a) zinc loading capacity, b) congruence with zinc physicochemical attributes, and c) release profile of their zinc load. The material antimicrobial properties were demonstrated against Gram-positive (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus) and negative (Escherichia coli, Pseudomonas aeruginosa, Xanthomonas campestris) bacteria using modified agar diffusion methods. ZnSO4 showed less extensive antimicrobial behavior compared to Zn(II)-Schiff, implying that the Zn(II)-bound ligand enhances zinc antimicrobial properties. All zinc-loaded nanoparticles were less antimicrobially active than zinc compounds alone, as encapsulation controls their release, thereby attenuating their antimicrobial activity. To this end, as the amount of loaded zinc increases, the antimicrobial behavior of the nano-agent improves. Collectively, for the first time, sol-gel zinc-loaded silica-nanoparticles were shown to exhibit well-defined antimicrobial activity, justifying due attention to further development of antibacterial nanotechnology.

  15. Enhanced Photophysical Properties of Nanopatterned Titania Nanodots/Nanowires upon Hybridization with Silica via Block Copolymer Templated Sol-Gel Process

    Directory of Open Access Journals (Sweden)

    Dinakaran Kannaiyan

    2010-10-01

    Full Text Available We fabricated titanium dioxide (TiO2-silica (SiO2 nanocomposite structures with controlled morphology by a simple synthetic approach using cooperative sol-gel chemistry and block copolymer (BCP self-assembly. Mixed TiO2-SiO2 sol-gel precursors were blended with amphiphilic poly(styrene-block-ethylene oxide (PS-b-PEO BCPs where the precursors were selectively incorporated into the hydrophilic PEO domains. Changing the volumetric ratio of TiO2-SiO2 sol-gel precursor from 5% to 20%, a stepwise structural inversion occurred from nanodot arrays to discrete nanowires. Template free hybrid inorganic nanostructures were produced after the removal of PS-b-PEO by irradiation of UV light. The morphological evolution and photophysical properties were investigated by microscopic studies, UV-visible absorption and photocatalytic properties.

  16. Rapid and sensitive suspension array for multiplex detection of organophosphorus pesticides and carbamate pesticides based on silica-hydrogel hybrid microbeads.

    Science.gov (United States)

    Wang, Xuan; Mu, Zhongde; Shangguan, Fengqi; Liu, Ran; Pu, Yuepu; Yin, Lihong

    2014-05-30

    A technique for multiplex detection of organophosphorus pesticides and carbamate pesticides has been developed using a suspension array based on silica-hydrogel hybrid microbeads (SHHMs). The main advantage of SHHMs, which consist of both silica and hydrogel materials, is that they not only could be distinguished by their characteristic reflection peak originating from the stop-band of the photonic crystal but also have low non-specific adsorption of proteins. Using fluorescent immunoassay, the LODs for fenitrothion, chlorpyrifos-methyl, fenthion, carbaryl and metolcarb were measured to be 0.02ng/mL, 0.012ng/mL, 0.04ng/mL, 0.05ng/mL and 0.1ng/mL, respectively, all of which are much lower than the maximum residue limits, as reported in the European Union pesticides database. All the determination coefficients for these five pesticides were greater than 0.99, demonstrating excellent correlations. The suspension array was specific and had no significant cross-reactivity with other chemicals. The results for the detection of pesticide residues collected from agricultural samples using this method agree well with those from liquid chromatography-tandem mass spectrometry. Our results showed that this simple method is suitable for simultaneous detection of these five pesticides residues in fruits and vegetables.

  17. Infrared Spectroscopic Study on Structural Change and Interfacial Interaction in Rubber Composites Filled with Silica-Kaolin Hybrid Fillers

    Science.gov (United States)

    Chen, Y.; Guan, J.; Hu, H.; Gao, H.; Zhang, L.

    2016-07-01

    A series of natural rubber/styrene butadiene rubber/polybutadiene rubber composites was prepared with nanometer silica and micron kaolin by a dry modification process, mechanical compounding, and mold vulcanization. Fourier transform infrared spectroscopy and a scanning electron microscope were used to investigate the structural changes and interfacial interactions in composites. The results showed that the "seesaw" structure was formed particularly with the incorporation of silica particles in the preparation process, which would be beneficial to the dispersibility of fillers in the rubber matrix. The kaolinite platelets were generally arranged in directional alignment. Kaolinite with smaller particle size and low-defect structure was more stable in preparation, but kaolinite with larger particle size and high defect structure tended to change the crystal structure. The composite prepared in this research exhibited excellent mechanical and thermal properties.

  18. In-situ reactions in hybrid aluminum alloy composites during incorporating silica sand in aluminum alloy melts

    Directory of Open Access Journals (Sweden)

    Benjamin F. Schultz

    2016-07-01

    Full Text Available In order to gain a better understanding of the reactions and strengthening behavior in cast aluminum alloy/silica composites synthesized by stir mixing, experiments were conducted to incorporate low cost foundry silica sand into aluminum composites with the use of Mg as a wetting agent. SEM and XRD results show the conversion of SiO2 to MgAl2O4 and some Al2O3 with an accompanying increase in matrix Si content. A three-stage reaction mechanism proposed to account for these changes indicates that properties can be controlled by controlling the base Alloy/SiO2/Mg chemistry and reaction times. Experimental data on changes of composite density with increasing reaction time and SiO2 content support the three-stage reaction model. The change in mechanical properties with composition and time is also described.

  19. Gated supramolecular chemistry in hybrid mesoporous silica nanoarchitectures: controlled delivery and molecular transport in response to chemical, physical and biological stimuli.

    Science.gov (United States)

    Alberti, Sebastián; Soler-Illia, Galo J A A; Azzaroni, Omar

    2015-04-11

    This review presents and discusses recent advances in the emerging field of "gated nanochemistry", outlining the substantial progress made so far. The development of hybrid mesoporous silica with complex tailored pore nanoarchitectures bridges the gap between molecular materials and the requirements of nanodevices for controlled nanoscale chemistry. In the last decade, membranes, particles and thin film porous architectures have been designed, synthesized and selectively modified by molecular, polymeric, organometallic or biologically active groups. The exquisite manipulation of mesopore morphology and interconnection combined with molecular or supramolecular functionalities, and the intrinsic biological compatibility of silica have made these materials a potential platform for selective sensing and drug delivery. The wide répertoire of these hard-soft architectures permit us to envisage sophisticated intelligent nano-systems that respond to a variety of external stimuli such as pH, redox potential, molecule concentration, temperature, or light. Transduction of these stimuli into a predefined response implies exploiting spatial and physico-chemical effects such as charge distribution, steric constraints, equilibria displacements, or local changes in ionic concentration, just to name a few examples. As expected, this "positional mesochemistry" can be only attained through the concerted control of assembly, surface tailoring and, confinement conditions, thus giving birth to a new class of stimuli-responsive materials with modulable transport properties. As a guiding framework the emerging field of "gated nanochemistry" offers methodologies and tools for building up stimuli-sensitive porous architectures equipped with switchable entities whose transport properties can be triggered at will. The gated nanoscopic hybrid materials discussed here not only herald a new era in the integrative design of "smart" drug delivery systems, but also give the reader a perspective of

  20. A hybrid enrichment process combining conjugated polymer extraction and silica gel adsorption for high purity semiconducting single-walled carbon nanotubes (SWCNT)

    Science.gov (United States)

    Ding, Jianfu; Li, Zhao; Lefebvre, Jacques; Cheng, Fuyong; Dunford, Jeffrey L.; Malenfant, Patrick R. L.; Humes, Jefford; Kroeger, Jens

    2015-09-01

    A novel purification process for the enrichment of sc-SWCNTs that combines selective conjugated polymer extraction (CPE) with selective adsorption using silica gel, termed hybrid-CPE (h-CPE), has been developed, providing a high purity sc-SWCNT material with a significant improvement in process efficiency and yield. Using the h-CPE protocol, a greater than 5 fold improvement in yield can be obtained compared to traditional CPE while obtaining sc-SWCNT with a purity >99.9% as assessed by absorption spectroscopy and Raman mapping. Thin film transistor devices using the h-CPE derived sc-SWCNTs as the semiconductor possess mobility values ranging from 10-30 cm2 V-1 s-1 and current ON/OFF ratio of 104-105 for channel lengths between 2.5 and 20 μm.A novel purification process for the enrichment of sc-SWCNTs that combines selective conjugated polymer extraction (CPE) with selective adsorption using silica gel, termed hybrid-CPE (h-CPE), has been developed, providing a high purity sc-SWCNT material with a significant improvement in process efficiency and yield. Using the h-CPE protocol, a greater than 5 fold improvement in yield can be obtained compared to traditional CPE while obtaining sc-SWCNT with a purity >99.9% as assessed by absorption spectroscopy and Raman mapping. Thin film transistor devices using the h-CPE derived sc-SWCNTs as the semiconductor possess mobility values ranging from 10-30 cm2 V-1 s-1 and current ON/OFF ratio of 104-105 for channel lengths between 2.5 and 20 μm. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04851f

  1. Multi-walled carbon nanotube-based ternary rare earth (Eu3+, Tb3+) hybrid materials with organically modified silica-oxygen bridge.

    Science.gov (United States)

    Li, Qiu-Ping; Yan, Bing

    2012-08-15

    A series of ternary rare earth (Eu(3+), Tb(3+)) complexes are covalently coated to the 3-aminopropyltriethoxysilane functionalized multi-walled carbon nanotube (MWCNT) by a simple in situ sol-gel method by the bifunctional silylated monomer TTA-Si and TAA-Si (TTA-Si and TAA-Si are 3-(triethoxysilyl)propylisocyanate (TEPIC) modified thenoyltrifluoroacetone (TTA) and trifluoroacetylacetone (TAA), respectively). The resulting materials are characterized by Fourier transform infrared spectra, scanning electronic microscope, transmission electron microscope, thermogravimetric analysis, ultraviolet visible diffused reflection measure, photoluminescence spectra, and X-ray diffraction. The photoluminesce measurements indicated that these hybrids exhibit characteristic red and green luminescence originating from the corresponding ternary rare earth ion (Eu(3+), Tb(3+)). The luminescence quenching effect of MWCNT networks have been successfully restrained by coating a relatively thicker silica-oxygen-based organic-inorganic complex. Furthermore, the fluorescence lifetimes and emission quantum efficiencies of Eu(3+) hybrid materials are also determined. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Pentynyl Ether of β-Cyclodextrin Polymer and Silica Micro-Particles: A New Hybrid Material for Adsorption of Phenanthrene from Water

    Directory of Open Access Journals (Sweden)

    Jae Min Choi

    2017-01-01

    Full Text Available A new hybrid material for the removal of polycyclic aromatic hydrocarbons (PAH from water was prepared by the polymerization of pentynyl beta-cyclodextrin (PyβCD and silica micro-particles (SMP. Phenanthrene, being one of the important members of the PAH family and a potential risk for environmental pollution, was selected for this study. Results show that phenanthrene removal efficiency of the SMP was improved significantly after hybridization with PyβCD-polymer. Approximately 50% of the phenanthrene was removed in the first 60 min and more than 95% was removed in less than 7 h when 25 mL of the 2 ppm aqueous phenanthrene solution was incubated with the 100 mg of SMP-PyβCD-polymer material. Infrared spectroscopy and thermal gravimetric analysis show that the enhanced efficiency of the SMP-PyβCD-polymer compared to the unmodified SMP was due to the formation of the inclusion complexation of phenanthrene with the PyβCD. These results indicate that SMP-PyβCD polymers have a potential to be applied as molecular filters in water purification systems and also for waste water treatment.

  3. Monolithic microwave integrated circuits

    Science.gov (United States)

    Pucel, R. A.

    Monolithic microwave integrated circuits (MMICs), a new microwave technology which is expected to exert a profound influence on microwave circuit designs for future military systems as well as for the commercial and consumer markets, is discussed. The book contains an historical discussion followed by a comprehensive review presenting the current status in the field. The general topics of the volume are: design considerations, materials and processing considerations, monolithic circuit applications, and CAD, measurement, and packaging techniques. All phases of MMIC technology are covered, from design to testing.

  4. Synthesis of Hierarchically Structured Hybrid Materials by Controlled Self-Assembly of Metal-Organic Framework with Mesoporous Silica for CO2 Adsorption.

    Science.gov (United States)

    Chen, Chong; Li, Bingxue; Zhou, Lijin; Xia, Zefeng; Feng, Nengjie; Ding, Jing; Wang, Lei; Wan, Hui; Guan, Guofeng

    2017-07-12

    The HKUST-1@SBA-15 composites with hierarchical pore structure were constructed by in situ self-assembly of metal-organic framework (MOF) with mesoporous silica. The structure directing role of SBA-15 had an obvious impact on the growth of MOF crystals, which in turn affected the morphologies and structural properties of the composites. The pristine HKUST-1 and the composites with different content of SBA-15 were characterized by XRD, N2 adsorption-desorption, SEM, TEM, FT-IR, TG, XPS, and CO2-TPD techniques. It was found that the composites were assembled by oriented growth of MOF nanocrystals on the surfaces of SBA-15 matrix. The interactions between surface silanol groups and metal centers induced structural changes and resulted in the increases in surface areas as well as micropore volumes of hybrid materials. Besides, the additional constraints from SBA-15 also restrained the expansion of HKUST-1, contributing to their smaller crystal sizes in the composites. The adsorption isotherms of CO2 on the materials were measured and applied to calculate the isosteric heats of adsorption. The HS-1 composite exhibited an increase of 15.9% in CO2 uptake capacity compared with that of HKUST-1. Moreover, its higher isosteric heats of CO2 adsorption indicated the stronger interactions between the surfaces and CO2 molecules. The adsorption rate of the composite was also improved due to the introduction of mesopores. Ten cycles of CO2 adsorption-desorption experiments implied that the HS-1 had excellent reversibility of CO2 adsorption. This study was intended to provide the possibility of assembling new composites with tailored properties based on MOF and mesoporous silica to satisfy the requirements of various applications.

  5. Synthesis and application of imprinted polyvinylimidazole-silica hybrid copolymer for Pb{sup 2+} determination by flow-injection thermospray flame furnace atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira Tarley, Cesar Ricardo, E-mail: tarley@uel.br [Programa de Pos-Graduacao em Quimica da Universidade Federal de Alfenas, Rua Gabriel Monteiro da Silva 700, Alfenas, MG, CEP 37130-000 (Brazil); Instituto Nacional de Ciencia e Tecnologia (INCT) de Bioanalitica, Universidade Estadual de Campinas (UNICAMP), Instituto de Quimica, Departamento de Quimica Analitica, Cidade Universitaria Zeferino Vaz s/n, Campinas, SP, CEP 13083-970 (Brazil); Departamento de Quimica, Universidade Estadual de Londrina, Rod. Celso Garcia Cid, PR 445 Km 380, Campus Universitario, Londrina, PR, CEP 86051-990 (Brazil); Nascimento Andrade, Felipe [Programa de Pos-Graduacao em Quimica da Universidade Federal de Alfenas, Rua Gabriel Monteiro da Silva 700, Alfenas, MG, CEP 37130-000 (Brazil); Midori de Oliveira, Fernanda; Zanetti Corazza, Marcela [Departamento de Quimica, Universidade Estadual de Londrina, Rod. Celso Garcia Cid, PR 445 Km 380, Campus Universitario, Londrina, PR, CEP 86051-990 (Brazil); Mendes de Azevedo, Luiz Fernando [Programa de Pos-Graduacao em Quimica da Universidade Federal de Alfenas, Rua Gabriel Monteiro da Silva 700, Alfenas, MG, CEP 37130-000 (Brazil); Gava Segatelli, Mariana [Universidade Tecnologica Federal do Parana (UTFPR), Av. dos Pioneiros 3131, Londrina, PR, CEP 86036-370 (Brazil)

    2011-10-10

    Highlights: {yields} Ion imprinted hybrid copolymer as selective sorbent for Pb{sup 2+} ions. {yields} The sorbent was at least 10 times more selective than non imprinted copolymer. {yields} A method for Pb{sup 2+} determination by TS-FF-AAS in different samples was developed. {yields} High reusability and chemical stability of ion imprinted hybrid copolymer were observed. - Abstract: A novel ion imprinted polyvinylimidazole-silica hybrid copolymer (IIHC) was synthesized and used as a selective solid sorbent for Pb{sup 2+} ions preconcentration using an on-line solid phase extraction (SPE) system coupled to TS-FF-AAS. The ionic hybrid sorbent was prepared using 1-vinylimidazole and 3-(trimethoxysilyl)propylmethacrylate as monomers, Pb{sup 2+} ions as template, tetraethoxysilane as reticulating agent and 2,2'-azobis-isobutyronitrile as initiator. The best on-line SPE conditions concerning sorption behavior, including sample pH (6.46), buffer concentration (9.0 mmol L{sup -1}), eluent (HNO{sub 3}) concentration (0.5 mol L{sup -1}) and preconcentration flow rate (4.0 mL min{sup -1}), were optimized by means of full factorial design and Doehlert matrix. The analytical curve ranged from 2.5 to 65.0 {mu}g L{sup -1} (r = 0.999) with limit of detection of 0.75 {mu}g L{sup -1}; the precision (repeatability) calculated as relative standard deviation (n = 10) was 5.0 and 3.6% for Pb{sup 2+} concentration of 10.0 and 60.0 {mu}g L{sup -1}, respectively. From on-line breakthrough curve, column capacity was 3.5 mg g{sup -1}. Preconcentration factor (PF), consumptive index (CI) and concentration efficiency (CE) were 128.0, 0.16 mL and 25.6 min{sup -1}, respectively. The selective performance of the sorbent, based on relative selectivity coefficient, was compared to NIC (non imprinted copolymer) for the binary mixture Pb{sup 2+}/Cd{sup 2+}, Pb{sup 2+}/Cu{sup 2+} and Pb{sup 2+}/Zn{sup 2+}. The results showed that ion imprinted polyvinylimidazole-silica hybrid polymer had higher

  6. Graphene oxide functionalized with silver@silica-polyethylene glycol hybrid nanoparticles for direct electrochemical detection of quercetin.

    Science.gov (United States)

    Veerapandian, Murugan; Seo, Yeong-Tai; Yun, Kyusik; Lee, Min-Ho

    2014-08-15

    A direct electrochemical detection of quercetin based on functionalized graphene oxide modified on gold-printed circuit board chip was demonstrated in this study. Functionalized graphene oxide materials are prepared by the covalent reaction of graphene oxide with silver@silica-polyethylene glycol nanoparticles (~12.35nm). Functionalized graphene oxide electrode shows a well-defined voltammetric response in phosphate buffered saline and catalyzes the oxidation of quercetin to quinone without the need of an enzyme. Significantly, the functionalized graphene oxide modified electrode exhibited a higher sensitivity than pristine gold-printed circuit board and graphene oxide electrodes, a wide concentration range of 7.5 to 1040nM and detection limit of 3.57nM. Developed biosensor platform is selective toward quercetin in the presence of an interferent molecule.

  7. Ruthenium carbenes supported on mesoporous silicas as highly active and selective hybrid catalysts for olefin metathesis reactions under continuous flow.

    Science.gov (United States)

    Bru, Miriam; Dehn, Richard; Teles, J Henrique; Deuerlein, Stephan; Danz, Manuel; Müller, Imke B; Limbach, Michael

    2013-08-26

    In the search for a highly active and selective heterogenized metathesis catalyst, we systematically varied the pore geometry and size of various silica-based mesoporous (i.e., MCM-41, MCM-48, and SBA-15) and microporous (ZSM-5 and MWW) versus macroporous materials (D11-10 and Aerosil 200), besides other process parameters (temperature, dilution, and mean residence time). The activity and, especially, selectivity of such "linker-free" supports for ruthenium metathesis catalysts were evaluated in the cyclodimerization of cis-cyclooctene to form 1,9-cyclohexadecadiene, a valuable intermediate in the flavor and fragrance industry. The optimized material showed not only exceptionally high selectivity to the valuable product, but also turned out to be a truly heterogeneous catalyst with superior activity relative to the unsupported homogeneous complex.

  8. Embedded-monolith armor

    Science.gov (United States)

    McElfresh, Michael W.; Groves, Scott E; Moffet, Mitchell L.; Martin, Louis P.

    2016-07-19

    A lightweight armor system utilizing a face section having a multiplicity of monoliths embedded in a matrix supported on low density foam. The face section is supported with a strong stiff backing plate. The backing plate is mounted on a spall plate.

  9. 整体材料的研制及其在蛋白质组色谱分离中的应用%Preparation of monolithic materials and applications in proteomic chromatographic separation

    Institute of Scientific and Technical Information of China (English)

    吴慈; 梁玉; 梁振; 张丽华; 张玉奎

    2016-01-01

    With the advantages of facile preparation,fast mass transfer,low backpressure and easy modifica-tion,monolithic materials have been widely used in chromatographic separation.In order to familiarize profes-sionals of home and abroad with the present situation of monolithic materials,this review mainly summarizes the preparation methods of different kinds of monolithic materials (including organic polymer monoliths,silica-based monoliths,organic-inorganic hybrid silica monoliths)and their applications in the separation of proteins or peptides in proteomics.It was pointed out that compared with packed column,monolithic packed column efficiency was to be further improved from the performance of monolithic materials,such as specific surface area,pore size distribution,stablity and hydrophilicity.Taking advantage of the low backpressure of monolithic materials,the capillary monolithic column with superlong and superfine inner diameter was prepared in order to make high efficient separation analysis of macro proteomics samples.With the further study of monolithic materials preparation technology,monolithic materials will play more important role in the fields of food safety, life science and environment.%整体材料由于具有制备简单、传质速度快、低背压、表面易于修饰等优势,在色谱分离领域中应用非常广泛。为使业界了解国内外对整体材料研制的现状,对有机聚合物整体材料、硅胶整体材料、有机-无机杂化整体材料三种整体材料的制备方法及其在蛋白质组学中蛋白质和肽段色谱分离中的应用进行了综述,指出:与填充柱相比,整体柱的分离柱效仍有待进一步提高,可以从整体材料的性能,如比表面积、孔径分布、稳定性、亲水性等方面进行改进。利用整体材料低背压的优势,可制备超长、超细内径毛细管整体柱,有利于微量蛋白质组学样品的高效分离分析。随着对整体材料制备

  10. Monolithic cells for solar fuels.

    Science.gov (United States)

    Rongé, Jan; Bosserez, Tom; Martel, David; Nervi, Carlo; Boarino, Luca; Taulelle, Francis; Decher, Gero; Bordiga, Silvia; Martens, Johan A

    2014-12-07

    Hybrid energy generation models based on a variety of alternative energy supply technologies are considered the best way to cope with the depletion of fossil energy resources and to limit global warming. One of the currently missing technologies is the mimic of natural photosynthesis to convert carbon dioxide and water into chemical fuel using sunlight. This idea has been around for decades, but artificial photosynthesis of organic molecules is still far away from providing real-world solutions. The scientific challenge is to perform in an efficient way the multi-electron transfer reactions of water oxidation and carbon dioxide reduction using holes and single electrons generated in an illuminated semiconductor. In this tutorial review the design of photoelectrochemical (PEC) cells that combine solar water oxidation and CO2 reduction is discussed. In such PEC cells simultaneous transport and efficient use of light, electrons, protons and molecules has to be managed. It is explained how efficiency can be gained by compartmentalisation of the water oxidation and CO2 reduction processes by proton exchange membranes, and monolithic concepts of artificial leaves and solar membranes are presented. Besides transferring protons from the anode to the cathode compartment the membrane serves as a molecular barrier material to prevent cross-over of oxygen and fuel molecules. Innovative nano-organized multimaterials will be needed to realise practical artificial photosynthesis devices. This review provides an overview of synthesis techniques which could be used to realise monolithic multifunctional membrane-electrode assemblies, such as Layer-by-Layer (LbL) deposition, Atomic Layer Deposition (ALD), and porous silicon (porSi) engineering. Advances in modelling approaches, electrochemical techniques and in situ spectroscopies to characterise overall PEC cell performance are discussed.

  11. Photonic integrated circuits based on silica and polymer PLC

    Science.gov (United States)

    Izuhara, T.; Fujita, J.; Gerhardt, R.; Sui, B.; Lin, W.; Grek, B.

    2013-03-01

    Various methods of hybrid integration of photonic circuits are discussed focusing on merits and challenges. Material platforms discussed in this report are mainly polymer and silica. We categorize the hybridization methods using silica and polymer waveguides into two types, chip-to-chip and on-chip integration. General reviews of these hybridization technologies from the past works are reviewed. An example for each method is discussed in details. We also discuss current status of our silica PLC hybrid integration technology.

  12. The Role of Silica in Precious Metal Supported Titania Hybrid Mesoporous Materials for Remediation and Energy Production

    Science.gov (United States)

    Kibombo, Harrison S.

    Semiconductor photocatalysis is an advanced oxidation process (AOP) that continues to show promise for the concomitant mineralization of non--biodegradable noxious and persistent organic pollutants (POPs) to environmentally benign products, and the splitting of water. This work examined the use of sol--gel chemistry as a viable approach for the incorporation of transparent silica (SiO2) matrix and/or platinum onto titania (TiO2) so as to optimize physico-chemical properties such as charge separation, crystallinity, surface area, and particle size. It was determined that crystallinity of anatase in the mixed oxide photocatalyst can be improved by the addition of simple non-polar aromatic co-solvents in the sol-gel route, and subsequently enhance the photocatalytic degradation of phenol under UV--light irradiation. The Pt of smaller particle sizes in Pt--TiO2--SiO 2 resulted in higher phenol degradation efficiencies under solar simulated conditions, irrespective of the synthesis method employed. The presence of Pt in the lowest oxidation state, Pt0, is crucial for enhanced phenol degradation whereas PtO2 (Pt4+) serves as a mild recombination center for photogenerated charge carriers rather than demonstrating total inactivity. The production of ·OH radicals was shown to be imperative for sustaining the degradation process. In the water splitting reaction for hydrogen production, the role of the crystallinity of anatase is reaffirmed when TiO2--SiO2 is used, as the surface defects present in the silica phase seem to serve as recombination centers. However, in Pt--TiO2 photocatalysts, the presence of Pt 0 or PtO2 in close contact with TiO2 (heterojunction) allows for more efficient electron propagation and facilitates minimization of electron--hole recombination, hence improved solar simulated photocatalytic hydrogen evolution. Extensive characterization of the photocatalysts were carried out by powder X--ray Diffraction (XRD), Nitrogen Physisorption Studies, Diffuse

  13. Mesoporous silica particle-PLA-PANI hybrid scaffolds for cell-directed intracellular drug delivery and tissue vascularization

    Science.gov (United States)

    Shokry, Hussein; Vanamo, Ulriika; Wiltschka, Oliver; Niinimäki, Jenni; Lerche, Martina; Levon, Kalle; Linden, Mika; Sahlgren, Cecilia

    2015-08-01

    Instructive materials are expected to revolutionize stem cell based tissue engineering. As many stem cell cues have adverse effects on normal tissue homeostasis, there is a need to develop bioactive scaffolds which offer locally retained and cell-targeted drug delivery for intracellular release in targeted cell populations. Further, the scaffolds need to support vascularization to promote tissue growth and function. We have developed an electrospun PLA-PANI fiber scaffold, and incorporated mesoporous silica nanoparticles within the scaffold matrix to obtain cell-targeted and localized drug delivery. The isotropy of the scaffold can be tuned to find the optimal morphology for a given application and the scaffold is electroactive to support differentiation of contractile tissues. We demonstrate that there is no premature drug release from particles under physiological conditions over a period of one week and that the drug is released upon internalization of particles by cells within the scaffold. The scaffold is biocompatible, supports muscle stem cell differentiation and cell-seeded scaffolds are vascularized in vivo upon transplantation on the chorioallantoic membrane of chicken embryos. The scaffold is a step towards instructive biomaterials for local control of stem cell differentiation, and tissue formation supported by vascularization and without adverse effects on the homeostasis of adjacent tissues due to diffusion of biological cues.Instructive materials are expected to revolutionize stem cell based tissue engineering. As many stem cell cues have adverse effects on normal tissue homeostasis, there is a need to develop bioactive scaffolds which offer locally retained and cell-targeted drug delivery for intracellular release in targeted cell populations. Further, the scaffolds need to support vascularization to promote tissue growth and function. We have developed an electrospun PLA-PANI fiber scaffold, and incorporated mesoporous silica nanoparticles within

  14. Hybrid molecularly imprinted poly(methacrylic acid-TRIM)-silica chemically modified with (3-glycidyloxypropyl)trimethoxysilane for the extraction of folic acid in aqueous medium.

    Science.gov (United States)

    de Oliveira, Fernanda Midori; Segatelli, Mariana Gava; Tarley, César Ricardo Teixeira

    2016-02-01

    In the present study a hybrid molecularly imprinted poly(methacrylic acid-trimethylolpropane trimethacrylate)-silica (MIP) was synthesized and modified with (3-glycidyloxypropyl)trimethoxysilane (GPTMS) with posterior opening of epoxy ring to provide hydrophilic properties of material in the extraction of folic acid from aqueous medium. The chemical and structural aggregates of hybrid material were characterized by means of Fourier Transform Infrared (FT-IR), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Thermogravimetric analysis (TGA) and textural data. Selectivity data of MIP were compared to non-imprinted polymer (NIP) through competitive sorption studies in the presence of caffeine, paracetamol or 4-aminobenzamide yielding relative selectivity coefficients (k′) higher than one unit, thus confirming the selective character of MIP even in the presence of structurally smaller compounds than the folic acid. The lower hydrophobic sorption by bovine serum albumin (BSA) in the MIP as compared to unmodified MIP proves the hydrophilicity of polymer surface by using GPTMS with opening ring. Under acid medium(pH 1.5) the sorption of folic acid onto MIP from batch experiments was higher than the one achieved for NIP. Equilibrium sorption of folic acid was reached at 120 min for MIP, NIP and MIP without GPTMS and kinetic sorption data were well described by pseudo-second-order, Elovich and intraparticle diffusion models. Thus, these results indicate the existence of different binding energy sites in the polymers and a complex mechanism consisting of both surface sorption and intraparticle transport of folic acid within the pores of polymers.

  15. Thermal oxidative and ozone oxidative stabilization effect of hybridized functional graphene oxide in a silica-filled solution styrene butadiene elastomer.

    Science.gov (United States)

    Su, Juqiao; Zhao, Zhongguo; Huang, Yajiang; Liao, Xia; Yang, Qi

    2016-10-26

    Hybridization of modified functional graphene oxide (fGO) in silica-filled solution styrene butadiene rubber (SSBR) endows preferable tensile and dynamic properties before and after thermal oxidative aging, and similar mechanical hysteresis performance compared with the composites without fGO. The preventing mechanism of fGO is attributed to its intrinsic peroxy radical scavenging and gas barrier abilities, which significantly reduces the peroxy radical concentration and oxygen permeability of nanocomposites and then prolongs oxidative induction time (OIT), characterized by differential scanning calorimetry (DSC). The ozone resisting effect of different loadings of fGO on nanocomposites have also been investigated by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) after ozonization under 50 ppm ozone concentration. As a result, incorporation of fGO apparently suppresses both the formation of oxygenic groups of the olefinic elastomer and crack morphology extension upon ozonization. We propose that fGO protects the SSBR elastomer from ozone attack through the conjugated delocalized π-bonds of the fGO instead of the C[double bond, length as m-dash]C bonds of the elastomer matrix being attacked, and the compared experiments, characterized by X-ray photoelectron spectroscopy (XPS), confirm that this presumption is perhaps reasonable. Moreover, more than 3 phr incorporation of fGO in nanocomposites deteriorates the chemical and mechanical properties of the elastomer during the thermal oxidation and ozonization because of the cleavage influence of oxygenic groups on peroxy radicals.

  16. QMX: A versatile environment for hybrid calculations applied to the grafting of Al 2 Cl 3 Me 3 on a silica surface

    KAUST Repository

    Kerber, Torsten

    2013-01-23

    We present a new software to easily perform QM:MM and QM:QM\\' calculations called QMX. It follows the subtraction scheme and it is implemented in the Atomic Simulation Environment (ASE). Special attention is paid to couple molecular calculations with periodic boundaries approaches. QMX inherits the flexibility and versatility of the ASE package: any combination of methods namely force field, semiempirical, first principle, and ab initio, can be used as hybrid potential energy surface (PES). Its ease of use is demonstrated by considering the adsorption of Al2Cl3Me3 on silica surface and by combining different levels of theory (from standard DFT to MP2 calculations) for the so-called High Level cluster with standard PW91 density functional theory calculations for the Low Level environment. It is shown that the High Level cluster must contain the silanol group close to the aluminum atoms. The bridging adsorption is favored by 58 kJ mol-1 at the MP2:PW91 level with respect to the terminal position. Using large clusters at the MP2:PW91 level, it is shown that PW91 calculations are sufficient for structure optimization but that embedded methods are required for accurate energy profiles. © 2013 Wiley Periodicals, Inc.

  17. SYNTHESIS OF HYBRID MESOPOROUS POLYSTYRENE-SILICA MATERIALS WITH NON-SURFACTANT CITRIC ACID AS TEMPLATE VIA SOL-GEL PROCESS

    Institute of Scientific and Technical Information of China (English)

    Jie Bai; Jin-yu Zheng; Kun-yuan Qiu; Yen Wei

    2002-01-01

    Hybrid mesoporous polystyrene-silica materials were successfully prepared through HCl-catalyzed sol-gelreactions of tetraethyl orthosilicate (TEOS) and triethoxysilyl-functionalized polystyrene obtained via atom transfer radicalpolymerization (ATRP) of styrene, in the presence of citric acid (CA) as non-surfactant template or pore-forming agent andfollowed by ethanol extraction to remove template molecules. The materials were characterized by infrared spectroscopy(IR), N2 adsorption-desorption measurements, powder X-ray diffraction (XRD), thermogravimetric analysis (TGA) andtransmission electron microscopy (TEM). The results indicate that the materials prepared with 50 wt%-60 wt% templatecontents have average pore size s of 2-3 nm and large surface areas (ca. 886 m2/g) as well as high pore volumes (ca.0.53 cm3/g). The mesoporosity arises from interconnected channels and pores with disordered arrangements. The porediameters and pore volumes increase as the template content is increased. The pore diameters show a little change uponheating at 200℃ overnight. However, the materials do not have good hydrothermal stability.

  18. Preparation of hybrid organic-inorganic mesoporous silicas applied to mercury removal from aqueous media: Influence of the synthesis route on adsorption capacity and efficiency.

    Science.gov (United States)

    Pérez-Quintanilla, Damián; Sánchez, Alfredo; Sierra, Isabel

    2016-06-15

    New hybrid organic-inorganic mesoporous silicas were prepared by employing three different synthesis routes and mercury adsorption studies were done in aqueous media using the batch technique. The organic ligands employed for the functionalization were derivatives of 2-mercaptopyrimidine or 2-mercaptothiazoline, and the synthesis pathways used were post-synthesis, post-synthesis with surface ion-imprinting and co-condensation with ion-imprinting. The incorporation of functional groups and the presence of ordered mesopores in the organosilicas was confirmed by XRD, TEM and SEM, nitrogen adsorption-desorption isotherms, (13)C MAS-NMR, (29)Si MAS-NMR, elemental and thermogravimetric analysis. The highest adsorption capacity and selectivity observed was for the material functionalized with 2-mercaptothiazoline ligand by means the co-condensation with ion-imprinting route (1.03 mmol g(-1) at pH 6). The prepared material could be potential sorbent for the extraction of this heavy metal from environmental and drinking waters. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Luminescent Organic–Inorganic Hybrids of Functionalized Mesoporous Silica SBA-15 by Thio-Salicylidene Schiff Base

    Directory of Open Access Journals (Sweden)

    Li Ying

    2010-01-01

    Full Text Available Abstract Novel organic–inorganic mesoporous luminescent hybrid material N, N′-bis(salicylidene-thiocarbohydrazide (BSTC-SBA-15 has been obtained by co-condensation of tetraethyl orthosilicate and the organosilane in the presence of Pluronic P123 surfactant as a template. N,N′-bis(salicylidene-thiocarbohydrazide (BSTC grafted to the coupling agent 3-(triethoxysilyl-propyl isocyanate (TESPIC was used as the precursor for the preparation of mesoporous materials. In addition, for comparison, SBA-15 doped with organic ligand BSTC was also synthesized, denoted as BSTC/SBA-15. This organic–inorganic hybrid material was well-characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy (HRTEM, and photoluminescence spectra, which reveals that they all have high surface area, uniformity in the mesostructure. The resulting materials (BSTC-SBA-15 and BSTC/SBA-15 exhibit regular uniform microstructures, and no phase separation happened for the organic and the inorganic compounds was covalently linked through Si–O bonds via a self-assemble process. Furthermore, the two materials have different luminescence range: BSTC/SBA-15 presents the strong dominant green luminescence, while BSTC-functionalized material BSTC-SBA-15 shows the dominant blue emission.

  20. Fused silica suspension for the VIRGO optics: status and perspectives

    CERN Document Server

    Amico, P; Carbone, L; Gammaitoni, L; Punturo, M; Travasso, F; Vocca, H

    2002-01-01

    Thermal noise in mirror suspension wires is the main limitation of low-frequency sensitivity of interferometric gravitational wave detectors. In order to minimize the pendulum thermal noise, a monolithic design, using a low dissipation material, is proposed for VIRGO. High mechanical Qs and high breaking strengths have been obtained for monolithic fused silica fibres. A low-dissipation and high-strength bonding technique using potassium silicate bonding is proposed.

  1. The MONOLITH prototype

    CERN Document Server

    Ambrosio, M; Bencivenni, G; Candela, A M; Chiarini, A; Chignoli, F; De Deo, M; D'Incecco, M; Gerli, S; Giusti, P; Gómez, F; Gustavino, C; Lindozzi, M; Mannocchi, G; Menghetti, H; Morello, C; Murtas, F; Paoluzzi, G; Pilastrini, R; Redaelli, N G; Santoni, M; Sartorelli, G; Terranova, F; Trinchero, G C

    2000-01-01

    MONOLITH (Massive Observatory for Neutrino Oscillation or LImits on THeir existence) is the project of an experiment to study atmospheric neutrino oscillations with a massive magnetized iron detector. The baseline option is a 34 kt iron detector based on the use of about 50000 m/sup 2/ of the glass Resistive Plate Chambers (glass RPCs) developed at the Laboratori Nazionali del Gran Sasso (LNGS). An 8 ton prototype equipped with 23 m/sup 2/ of glass RPC has been realized and tested at the T7-PS beam at CERN. The energy resolution for pions follows a 68%/ square root (E(GeV))+2% law for orthogonally incident particles, in the energy range between 2 and 10 GeV. The time resolution and the tracking capability of the glass RPC are suitable for the MONOLITH experiment. (7 refs).

  2. Fabrication of three-dimensional MoS2-graphene hybrid monoliths and their catalytic performance for hydrodesulfurization%3D二硫化钼/石墨烯组装体的制备及其催化脱硫性能

    Institute of Scientific and Technical Information of China (English)

    王旭珍; 刘宁; 胡涵; 王新平; 邱介山

    2014-01-01

    A simple process to synthesize three-dimensional molybdenum disulfide-graphene monolithic catalysts (3D-MoS2-G) was developed. 3D-MoS2-G hybrid monoliths were fabricated by a combined hydrothermal self-assembly and freeze-drying treat-ment, in which ammonium tetrathiomolybdate and graphite oxide were used as starting materials. The structure and morphology of the samples were characterized by X-ray diffraction, Fourier transform infrared spectrometry, Raman spectrometry, field emission scanning electron microscopy, transmission electron microscopy and nitrogen adsorption. The catalytic performance of the hybrid monoliths was investigated by evaluating the activity for the hydrodesulfurization ( HDS) of carbonyl sulfide ( COS) . In addition, the influence of microwave irradiation on the catalytic property of the 3D-MoS2-G monoliths was also investigated. It is demonstra-ted that after microwave irradiation the 3D-MoS2-G monoliths show an excellent activity for COS hydrogenation compared with the traditional MoS2/γ-Al2 O3 catalyst prepared by impregnation-sulfidation. The 3D-MoS2-G-160M monolith hydrothermally synthe-sized at 160℃ exhibits the highest COS conversion of 100% at a relatively low temperature (260℃) for the HDS reaction. The su-perior performance of the 3D-MoS2-G-160M catalyst can be ascribed to the unique hybridized structure of the MoS2 nanoparticles u-niformly dispersed on graphene sheets in the monolith.%采用水热合成法,原位一步还原硫钼酸铵/氧化石墨前驱体,得到三维的二硫化钼/石墨烯(3D-MoS2/G)组装体催化剂。通过X-射线衍射仪、傅里叶变换红外光谱仪、拉曼光谱仪、场发射扫描电镜、透射电镜以及低温氮吸附等手段对其结构和形貌进行表征。以羰基硫( COS)的催化加氢转化为评价指标,对比研究微波处理前/后组装体催化剂的加氢脱硫性能。与传统硫化法制备的MoS2/γ-Al2 O3催化剂相比,经微波处理的水热一步法构筑的3

  3. Dihydrogenimidazole modified silica-sulfonated poly(ether ether ketone) hybrid materials as electrolyte membranes for direct ethanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Roelofs, Kimball S.; Hirth, Thomas [Fraunhofer Institute for Interfacial Engineering and Biotechnology, Nobelstr. 12, 70569 Stuttgart (Germany); Schiestel, Thomas, E-mail: Thomas.Schiestel@igb.fraunhofer.de [Fraunhofer Institute for Interfacial Engineering and Biotechnology, Nobelstr. 12, 70569 Stuttgart (Germany)

    2011-05-25

    The present study reports on dihydrogenimidazole modified inorganic-organic mixed matrix membranes for possible application as a proton exchange membrane in direct ethanol fuel cells. The polymeric phase consisted mainly of sulfonated poly(ether ether ketone) (sPEEK) with a sulfonation degree of 55%. The inorganic phase was built up from hydrophilic fumed silica particles interconnected with partially hydrolyzed and condensed tetraethoxysilane with a total inorganic loading of 27.3%. This inorganic phase was further modified with N-(3-triethoxysilylpropyl)-4,5-dihydroimidazole (DHIM), which consists of an hydrolyzable inorganic part and a functional organic group. The influence of the modifier on the mixed matrix system was studied by means of various modifier concentrations in various aqueous-ethanolic systems (water, 2 M and 4 M ethanol). Modifier concentration and ethanol concentration of the ethanol-water mixture exhibited significant but opposite effects on the liquid uptake of the mixed matrix membranes. The proton conductivity as well as the proton diffusion coefficient as a function of modifier content showed a linear decrease. The proton conductivity as a function of temperature showed Arrhenius behavior and the activation energy of the mixed matrix membranes was 43.9 {+-} 2.6 kJ mol{sup -1}. High selectivity of proton diffusion coefficient to ethanol permeability coefficient was obtained with high modifier concentrations. At low modifier concentrations, this selectivity was dominated by ethanol permeation and at high modifier concentrations by proton diffusion. The main electrolyte properties can be optimized by setting the DHIM content in mixed matrix membrane. With this approach, tailor-made membranes can be prepared for possible application in direct ethanol fuel cells.

  4. Recent Research and Development of Monolithic Column in Ion Chromatography%整体柱离子色谱的研究进展

    Institute of Scientific and Technical Information of China (English)

    陈倩; 于泓

    2011-01-01

    Monolithic columns have been employed in low pressure, fast and high efficient separation, for their many excellent characteristics. When applied to ion chromatography field, monolithic columns can achieve more effective analysis than traditional columns. Therefore, the method of ion chromatography based on monolithic columns attracts increasing interests. In this paper, the sorts of ion chromatography, classification of monolithic stationary phases, preparation ways of monolithic columns, performances and features of monolithic columns were introduced. The application of conventional monolithic columns in ion chromatography and the utilization of capillary monolithic columns in capillary ion chromatography were summarized according to the different assortments and properties of monolithic columns and ion chromatography, which included silica-based monolithic stationary phase and organic polymer-based monolithic stationary phase. The development of ion chromatography based on monolithic columns in the future was reviewed and prospected.%该文介绍了离子色谱的分类,整体柱的分类、制备及特点,并以此为依据归纳总结了常规整体柱在离子色谱中的应用和毛细管整体柱在毛细管离子色谱中的应用,其中包括硅胶基质整体柱和聚合物基质整体柱,评述并展望了整体柱离子色谱的发展前景.

  5. Coumarin-based fluorescence hybrid silica material used for selective detection and absorption of Hg2+ in aqueous media

    Science.gov (United States)

    Meng, Qingtao; Jia, Hongmin; Wang, Cuiping; Zhao, Hongbin; Lu, Gonghao; Hu, Zhizhi; Zhang, Zhiqiang; Duan, Chunying

    2014-11-01

    An inorganic-organic hybrid fluorescence material (C-SBA-15) was prepared by covalent immobilization of a coumarin derivative within the channels of SBA-15. The characterization results of XRD, TEM micrographs, FT-IR and UV-vis demonstrate that coumarin is successfully grafted onto the inner surface of SBA-15 and its organized structure is preserved. C-SBA-15 can detect Hg2+ with high selectivity to Pb2+, Zn2+, Cu2+, Mn2+, Cd2+, Co2+, Ag+, Fe3+, Ni2+, K+, Na+, Ca2+, Mg2+ and Li+ in water. Furthermore, the fluorogenical response is reversible by treating with EDTA and do not vary over a broad pH range (5.0-10.5). C-SBA-15 features more outstanding absorbing capacity for Hg2+ among other HTM ions in water.

  6. Monolithic columns in plant proteomics and metabolomics.

    Science.gov (United States)

    Rigobello-Masini, Marilda; Penteado, José Carlos Pires; Masini, Jorge Cesar

    2013-03-01

    Since "omics" techniques emerged, plant studies, from biochemistry to ecology, have become more comprehensive. Plant proteomics and metabolomics enable the construction of databases that, with the help of genomics and informatics, show the data obtained as a system. Thus, all the constituents of the system can be seen with their interactions in both space and time. For instance, perturbations in a plant ecosystem as a consequence of application of herbicides or exposure to pollutants can be predicted by using information gathered from these databases. Analytical chemistry has been involved in this scientific evolution. Proteomics and metabolomics are emerging fields that require separation, identification, and quantification of proteins, peptides, and small molecules of metabolites in complex biological samples. The success of this work relies on efficient chromatographic and electrophoretic techniques, and on mass spectrometric detection. This paper reviews recent developments in the use of monolithic columns, focusing on their applications in "top-down" and "bottom-up" approaches, including their use as supports for immobilization of proteolytic enzymes and their use in two-dimensional and multidimensional chromatography. Whereas polymeric columns have been predominantly used for separation of proteins and polypeptides, silica-based monoliths have been more extensively used for separation of small molecules of metabolites. Representative applications in proteomics and in analysis of plant metabolites are given and summarized in tables.

  7. Tuning the phase behavior of ionic liquids in organically functionalized silica ionogels.

    Science.gov (United States)

    Göbel, Ronald; Friedrich, Alwin; Taubert, Andreas

    2010-01-14

    We have synthesized mesoporous silica monoliths functionalized with 2-(4-pyridylethyl)triethoxysilane 1 and N,N-dimethyl-pyridine-4-yl-(3-triethoxysilyl-propyl)-ammonium iodide 2. The organically modified silica monoliths were characterized via IR spectroscopy, nitrogen sorption, small angle X-ray scattering (SAXS), thermogravimetric analysis-differential thermal analysis (TGA-DTA), and acid-base titration. The degree of functionalization can be changed by the ratio of the functional silane to the silica precursor tetramethyl orthosilicate (TMOS). The functionalized silica monoliths were filled with 1-ethyl-3-methyl imidazolium [Emim]-X (X = dicyanamide [N(CN)2] or triflate [TfO]) ionic liquids (ILs) using an established methanol-IL exchange technique. The phase behavior of the resulting ionogels was investigated via differential scanning calorimetry (DSC). DSC curves show that the modification of the silica pore walls with organic groups strongly affects the phase behavior of the confined ILs. Modification with silane 1 completely suppresses the glassy state of [Emim][TfO] previously observed in unmodified silica monoliths (Göbel et al., Phys. Chem. Chem. Phys. 2009, 11, 3653). In contrast, modification with silane 2 leads to the appearance and disappearance, respectively, of a presumed additional phase in [Emim][TfO] and [Emim][N(CN)2] with varying degree of monolith functionalization. The data thus show that organic modification of silica matrix materials could be a viable approach for the tuning of ionogel properties.

  8. Preparation and Properties of Silver-doped Silica Hybrid Membranes by Sol-gel Method%溶胶-凝胶法载银SiO2杂化膜的制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    杨靖; 于春雁; 刘华华

    2011-01-01

    The silver-doped methyl-modified hybrid silica (Ag/M-SiO2) membranes were prepared using the sol-gel method by adding AgNO3 solution to a methyl-modified silica sol. The influence of Ag-doping on the structure and properties of hybrid silica membranes was investigated by using XRD, XPS, UV-visible absorption spectra, N2 adsorption-desorption measurements and gas permeance experiments. The results show that the silver element in the Ag/M-SiO2 membranes exists in the metallic silver with a face centered cubic lattice. The doping of silver nanoparti-cles nearly has no influence on the chemical structure of the methyl-modified silica membranes, but can make the mean pore size and total pore volume slightly increase. Compared with the methyl-modified silica membranes without silver-doping, the H2 permeance and H2/CO2 permselectivities of Ag/M-SiO2 membranes are greater. The introduction of metallic silver facilitates the transport of H2 in silica membranes and improves the steam stability of silica membranes.%采用溶胶-凝胶法,在甲基化改性的SiO2溶胶中掺杂硝酸银,制备Ag/M-SiO2杂化膜.通过XRD、XPS、紫外-可见吸收谱、N2吸附-脱附以及气体渗透性能测试等方法,考察了银掺杂对杂化膜结构和性能的影响.结果表明,Ag/M-SiO2膜中的银元素完全为纳米金属银,具有面心立方结构.金属银的掺杂对Ag/M-SiO2膜的化学结构基本没有影响,但使其孔径和总孔体积略微增大.与未载银的SiO2膜相比,Ag/M-SiO2膜具有更大的H2渗透速率和更好的H2/CO2选择性.金属银的引入增强了H2的表面扩散作用,促进了H2在膜中的传递,提高了SiO2膜的水汽稳定性.

  9. ZIC-HILIC monolithic capillary column coupled with MALDI-MS: A tool for glycan analysis

    OpenAIRE

    Šesták, J. (Jozef); Křenková, J. (Jana); Moravcová, D. (Dana); Planeta, J. (Josef); Kahle, V. (Vladislav)

    2014-01-01

    In this contribution, we report analysis of glycans enzymatically released from bovine ribonuclease B (RNase B) and human immunoglobulin G (hIgG) combining glycan separation using the synthesized zwitterionic silica-based monolithic capillary column and off-line MALDI-MS detection.

  10. Monolithic liquid-chromatography columns for protein analysisprotein digest separation and integrated systems

    NARCIS (Netherlands)

    van de Meent, M.H.M.

    2010-01-01

    The objectives of the research described in this thesis are to evaluate the applicability of both silica-based and polymeric monolithic columns for protein analysis. The first part describes investigations into the effects of column length and stationary-phase chemistry on the separation of protein

  11. First acidic macro-mesocellular aluminosilicate monolithic foams "SiAl(HIPE)" and their catalytic properties.

    Science.gov (United States)

    Debecker, Damien P; Boissière, Cédric; Laurent, Guillaume; Huet, Stéphanie; Eliaers, Philippe; Sanchez, Clément; Backov, Rénal

    2015-09-25

    A new type of acidic macrocellular and mesoporous silica-alumina foam is obtained via a one pot alkaline sol-gel route coupled with a concentrated emulsion-based templating technique. The mixed oxide monolith exhibits high surface acidity, translating into excellent performance in the acid-catalyzed dehydration of bioethanol to ethene.

  12. Miniaturized DNA aptamer-based monolithic sorbent for selective extraction of a target analyte coupled on-line to nanoLC.

    Science.gov (United States)

    Brothier, Fabien; Pichon, Valérie

    2014-12-01

    A complete characterization of a novel target-specific DNA aptamer-based miniaturized solid phase extraction (SPE)-sorbent coupled on-line to nanoLC is presented. A miniaturized oligosorbent (mOS) was prepared via the in situ sol-gel synthesis of a hybrid organic-inorganic monolith in 100 μm i.d. capillary columns using tetraethoxysilane and 3-aminopropyltriethoxysilane as precursors, followed by covalent binding of a 5'-amino-modified DNA aptamer with a C12 spacer arm specific for a molecule of small molecular weight. Ochratoxin A (OTA), one of the most abundant naturally occurring mycotoxins, was chosen as model analyte to demonstrate the principle of such an approach. The mOS was coupled on-line to RP-nanoLC-LIF. Selective extraction of OTA on several mOSs was demonstrated with an average extraction recovery above 80 % when percolating spiked binding buffer and a low recovery on control monoliths grafted with a non-specific aptamer. Reproducibility of mOSs preparation was highlighted by comparing extraction yields. Otherwise, the mOSs demonstrated no cross-reactivity towards an OTA structural analogue, i.e., ochratoxin B. Due to the high specific surface area of the hybrid silica-based monolith, the coverage density of DNA aptamers covalently immobilized in the capillaries was very high and reached 6.27 nmol μL(-1), thus leading to a capacity above 5 ng of OTA. This miniaturized device was then applied to the selective extraction of OTA from beer samples. It revealed to be effective in isolating OTA from this complex matrix, thus improving the reliability of its analysis at the trace level.

  13. Bioaffinity chromatography on monolithic supports

    NARCIS (Netherlands)

    Tetala, K.K.R.; Beek, van T.A.

    2010-01-01

    Affinity chromatography on monolithic supports is a powerful analytical chemical platform because it allows for fast analyses, small sample volumes, strong enrichment of trace biomarkers and applications in microchips. In this review, the recent research using monolithic materials in the field of bi

  14. Bioaffinity chromatography on monolithic supports

    NARCIS (Netherlands)

    Tetala, K.K.R.; Beek, van T.A.

    2010-01-01

    Affinity chromatography on monolithic supports is a powerful analytical chemical platform because it allows for fast analyses, small sample volumes, strong enrichment of trace biomarkers and applications in microchips. In this review, the recent research using monolithic materials in the field of bi

  15. Design of monoliths through their mechanical properties.

    Science.gov (United States)

    Podgornik, Aleš; Savnik, Aleš; Jančar, Janez; Krajnc, Nika Lendero

    2014-03-14

    Chromatographic monoliths have several interesting properties making them attractive supports for analytics but also for purification, especially of large biomolecules and bioassemblies. Although many of monolith features were thoroughly investigated, there is no data available to predict how monolith mechanical properties affect its chromatographic performance. In this work, we investigated the effect of porosity, pore size and chemical modification on methacrylate monolith compression modulus. While a linear correlation between pore size and compression modulus was found, the effect of porosity was highly exponential. Through these correlations it was concluded that chemical modification affects monolith porosity without changing the monolith skeleton integrity. Mathematical model to describe the change of monolith permeability as a function of monolith compression modulus was derived and successfully validated for monoliths of different geometries and pore sizes. It enables the prediction of pressure drop increase due to monolith compressibility for any monolith structural characteristics, such as geometry, porosity, pore size or mobile phase properties like viscosity or flow rate, based solely on the data of compression modulus and structural data of non-compressed monolith. Furthermore, it enables simple determination of monolith pore size at which monolith compressibility is the smallest and the most robust performance is expected. Data of monolith compression modulus in combination with developed mathematical model can therefore be used for the prediction of monolith permeability during its implementation but also to accelerate the design of novel chromatographic monoliths with desired hydrodynamic properties for particular application.

  16. Polyurea-Based Aerogel Monoliths and Composites

    Science.gov (United States)

    Lee, Je Kyun

    2012-01-01

    aerogel insulation material was developed that will provide superior thermal insulation and inherent radiation protection for government and commercial applications. The rubbery polyureabased aerogel exhibits little dustiness, good flexibility and toughness, and durability typical of the parent polyurea polymer, yet with the low density and superior insulation properties associated with aerogels. The thermal conductivity values of polyurea-based aerogels at lower temperature under vacuum pressures are very low and better than that of silica aerogels. Flexible, rubbery polyurea-based aerogels are able to overcome the weak and brittle nature of conventional inorganic and organic aerogels, including polyisocyanurate aerogels, which are generally prepared with the one similar component to polyurethane rubber aerogels. Additionally, with higher content of hydrogen in their structures, the polyurea rubber-based aerogels will also provide inherently better radiation protection than those of inorganic and carbon aerogels. The aerogel materials also demonstrate good hydrophobicity due to their hydrocarbon molecular structure. There are several strategies to overcoming the drawbacks associated with the weakness and brittleness of silica aerogels. Development of the flexible fiber-reinforced silica aerogel composite blanket has proven to be one promising approach, providing a conveniently fielded form factor that is relatively robust in industrial environments compared to silica aerogel monoliths. However, the flexible, silica aerogel composites still have a brittle, dusty character that may be undesirable, or even intolerable, in certain application environments. Although the cross - linked organic aerogels, such as resorcinol- formaldehyde (RF), polyisocyanurate, and cellulose aerogels, show very high impact strength, they are also very brittle with little elongation (i.e., less rubbery). Also, silica and carbon aerogels are less efficient radiation shielding materials due

  17. Carbon monolith: preparation, characterization and application as microextraction fiber.

    Science.gov (United States)

    Shi, Zhi-Guo; Chen, Fei; Xing, Jun; Feng, Yu-Qi

    2009-07-10

    A carbon monolith was synthesized via a polymerization-carbonization method, styrene and divinylbenzene being adopted as precursors and dodecanol as a porogen during polymerization. The resultant monolith had bimodal porous substructure, narrowly distributed nano skeleton pores and uniform textural pores or throughpores. The carbon monolith was directly used as an extracting fiber, taking place of the coated silica fibers in commercially available solid-phase microextraction device, for the extraction of phenols followed by gas chromatography-mass spectrometry. Under the studied conditions, the calibration curves were linear from 0.5 to 50 ng mL(-1) for phenol, o-nitrophenol, 2,4-dichlorophenol and p-chlorophenol. The limits of detection were between 0.04 and 0.43 ng mL(-1). The recoveries of the phenols spiked in real water samples at 10 ng mL(-1) were between 85% and 98% with the relative standard deviations below 10%. Compared with the commercial coated ones (e.g. PDMS, CW/DVB and DVB/CAR/PDMS), the carbon monolith-based fiber had advantages of faster extraction equilibrium and higher extraction capacity due to the superior pore connectivity and pore openness resulting from its bimodal porous substructure.

  18. Porous polymer monolithic col

    Directory of Open Access Journals (Sweden)

    Lydia Terborg

    2015-05-01

    Full Text Available A new approach has been developed for the preparation of mixed-mode stationary phases to separate proteins. The pore surface of monolithic poly(glycidyl methacrylate-co-ethylene dimethacrylate capillary columns was functionalized with thiols and coated with gold nanoparticles. The final mixed mode surface chemistry was formed by attaching, in a single step, alkanethiols, mercaptoalkanoic acids, and their mixtures on the free surface of attached gold nanoparticles. Use of these mixtures allowed fine tuning of the hydrophobic/hydrophilic balance. The amount of attached gold nanoparticles according to thermal gravimetric analysis was 44.8 wt.%. This value together with results of frontal elution enabled calculation of surface coverage with the alkanethiol and mercaptoalkanoic acid ligands. Interestingly, alkanethiols coverage in a range of 4.46–4.51 molecules/nm2 significantly exceeded that of mercaptoalkanoic acids with 2.39–2.45 molecules/nm2. The mixed mode character of these monolithic stationary phases was for the first time demonstrated in the separations of proteins that could be achieved in the same column using gradient elution conditions typical of reverse phase (using gradient of acetonitrile in water and ion exchange chromatographic modes (applying gradient of salt in water, respectively.

  19. Formulation of Aminosilica Adsorbents into 3D-Printed Monoliths and Evaluation of Their CO2 Capture Performance.

    Science.gov (United States)

    Thakkar, Harshul; Eastman, Stephen; Al-Mamoori, Ahmed; Hajari, Amit; Rownaghi, Ali A; Rezaei, Fateme

    2017-03-01

    Amine-based materials have represented themselves as a promising class of CO2 adsorbents; however, their large-scale implementation requires their formulation into suitable structures. In this study, we report formulation of aminosilica adsorbents into monolithic structures through a three-dimensional (3D) printing technique. In particular, 3D-printed monoliths were fabricated using presynthesized silica-supported tetraethylenepentamine (TEPA) and poly(ethylenimine) (PEI) adsorbents using three different approaches. In addition, a 3D-printed bare silica monolith was prepared and post-functionalized with 3-aminopropyltrimethoxysilane (APS). Characterization of the obtained monoliths indicated that aminosilica materials retained their characteristics after being extruded into 3D-printed configurations. Adsorptive performance of amine-based structured adsorbents was also investigated in CO2 capture. Our results indicated that aminosilica materials retain their structural, physical, and chemical properties in the monoliths. In addition, the aminosilica monoliths exhibited adsorptive characteristics comparable to their corresponding powders. This work highlights the importance of adsorbent materials formulations into practical contactors such as monoliths, as the scalabale technology platform, that could facilitate rapid deployment of adsorption-based CO2 capture processes on commercial scales.

  20. Biobased monoliths for adenovirus purification.

    Science.gov (United States)

    Fernandes, Cláudia S M; Gonçalves, Bianca; Sousa, Margarida; Martins, Duarte L; Barroso, Telma; Pina, Ana Sofia; Peixoto, Cristina; Aguiar-Ricardo, Ana; Roque, A Cecília A

    2015-04-01

    Adenoviruses are important platforms for vaccine development and vectors for gene therapy, increasing the demand for high titers of purified viral preparations. Monoliths are macroporous supports regarded as ideal for the purification of macromolecular complexes, including viral particles. Although common monoliths are based on synthetic polymers as methacrylates, we explored the potential of biopolymers processed by clean technologies to produce monoliths for adenovirus purification. Such an approach enables the development of disposable and biodegradable matrices for bioprocessing. A total of 20 monoliths were produced from different biopolymers (chitosan, agarose, and dextran), employing two distinct temperatures during the freezing process (-20 °C and -80 °C). The morphological and physical properties of the structures were thoroughly characterized. The monoliths presenting higher robustness and permeability rates were further analyzed for the nonspecific binding of Adenovirus serotype 5 (Ad5) preparations. The matrices presenting lower nonspecific Ad5 binding were further functionalized with quaternary amine anion-exchange ligand glycidyltrimethylammonium chloride hydrochloride by two distinct methods, and their performance toward Ad5 purification was assessed. The monolith composed of chitosan and poly(vinyl) alcohol (50:50) prepared at -80 °C allowed 100% recovery of Ad5 particles bound to the support. This is the first report of the successful purification of adenovirus using monoliths obtained from biopolymers processed by clean technologies.

  1. Monolithic microchannel heatsink

    Science.gov (United States)

    Benett, William J.; Beach, Raymond J.; Ciarlo, Dino R.

    1996-01-01

    A silicon wafer has slots sawn in it that allow diode laser bars to be mounted in contact with the silicon. Microchannels are etched into the back of the wafer to provide cooling of the diode bars. To facilitate getting the channels close to the diode bars, the channels are rotated from an angle perpendicular to the diode bars which allows increased penetration between the mounted diode bars. This invention enables the fabrication of monolithic silicon microchannel heatsinks for laser diodes. The heatsinks have low thermal resistance because of the close proximity of the microchannels to the laser diode being cooled. This allows high average power operation of two-dimensional laser diode arrays that have a high density of laser diode bars and therefore high optical power density.

  2. Synthesis of hollow silica nanosphere with high accessible surface area and their hybridization with carbon matrix for drastic enhancement of electrochemical property

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Mohammad Mydul; Yamahana, Haruki [Department of Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan); Bastakoti, Bishnu Prasad [World Premier International (WPI) Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science - NIMS, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Luitel, Hom Nath; Zhao, Wenwen [Department of Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan); Yamauchi, Yusuke [World Premier International (WPI) Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science - NIMS, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Department of Nanoscience and Nanoengineering, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan); Watari, Takanori; Noguchi, Hideyuki [Department of Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan); Nakashima, Kenichi, E-mail: nakashik@cc.saga-u.ac.jp [Department of Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan)

    2014-09-30

    Highlights: • Hollow silica nanosphere with large void space and high surface area is synthesized. • Carbon was doped into silica layer through glucose solution and resulting carbon/silica composite drastically enhanced electrochemical property. • Combination of core–shell–corona micelle template and doping method could be a new platform for developing functional materials. - Abstract: Hollow silica nanospheres with high accessible surface area have been synthesized by using core–shell–corona polymeric micelle of poly (styrene-b-2-vinyle pyridine-b-ethylene oxide) (PS45k-PVP26k-PEO82k) as a template. The size of the template polymeric micelle depends on the pH of the solution, i.e. ≈100 nm at pH 7 whereas ≈300 nm at pH 4. The enlarged size of the micelle is possibly due to the protonation of the PVP block, which also serves as reaction sites for silica precursor. The size of the obtained silica nanosphere measured with transmission electron microscope (TEM) is around ≈70 nm and shell thickness is ≈20 nm. Fourier transformed infrared spectroscopy (FTIR) data confirms that the polymer template is completely removed during calcination. Conductive carbon is doped into the silica nanosphere through glucose solution followed by hydrothermal treatment and pyrolysis. It is found that the electrochemical performance and stability of the silica nanosphere is dramatically enhanced after carbon doping. The combined strategy of the core–shell–corona micelle as template and carbon doping could represent a new platform for the researchers to develop functional nanomaterials.

  3. Proximity focusing RICH detector based on multilayer silica aerogel radiator

    CERN Document Server

    De Leo, R; Bellunato, T; Calvi, M; Cisbani, E; Cusanno, F; Garibaldi, F; Lagamba, L; Marra, M; Marrone, S; Matteuzzi, C; Musico, P; Nappi, E; Perego, D L; Torrioli, S; Vilardi, I

    2010-01-01

    The performance of a proximity focusing Ring Imaging Cherenkov detector equipped with a radiator of silica aerogel is presented. The aerogel tile used is a monolith with variable index of refraction. Cherenkov photons are detected with high granularity by eight Hamamatsu H9500 flat panel multi anode phototubes.

  4. Preparation and characterization of polyimide/silica/silver composite films

    Institute of Scientific and Technical Information of China (English)

    Ning LUO; Zhanpeng WU; Nanxiang MOU; Lizhong JIANG; Dezhen WU

    2008-01-01

    Polyimide/silica/silver hybrid films were pre-pared by the sol-gel method combined with in situ single-stage self-metallization technique.The structure of polyi-mide films in the thermal curing process and the influence of silica content on the migration and aggregation of silver particles to the surface of hybrid films were investigated.The hybrid films were characterized by transmission elec-tron microscopy,dynamic mechanical thermal analysis,Fourier transform infrared spectroscopy,ultraviolet visible spectroscopy and mechanical measurements.The results indicated that there was no degradation of the polyimide matrix after the formation of silica and silver particles.Silica acted as the nucleus for the silver particles.With increasing silica content,more and more silver particles were kept in the hybrid films instead of being migrated onto the surface of the hybrid films and the reflections of hybrid films decreased gradually.

  5. 有机-无机杂化介孔二氧化硅在环境保护中的应用%Organic-Inorganic Hybrid Mesoporous Silicas and Their Applications in Environmental Protection

    Institute of Scientific and Technical Information of China (English)

    郭风; 朱桂茹; 高从堦

    2011-01-01

    Mesoporous organic-inorganic hybrid materials have been obtained through the coupling of inorganic and organic components by template synthesis. The incorporation of functionalities onto material pore surfaces or into the frameworks can be achieved by post-synthesis grafting or co-condensation method. The classification and synthesis methods of hybrid mesoporous silica materials are reviewed. Besides, the applications of hybrid materials in environmental protection are highlighted, including removal and recovery of metal cations,oxyanions, organic pollutants and gases. The outlook of the organic-inorganic hybrid mesoporous silicas is provided.%将有机基团通过后嫁接或共缩聚法引入到介孔二氧化硅的孔道表面或骨架中,根据有机基团在材料中的位置可得到表面结合型和桥键型两类功能化介孔材料.本文总结了有机-无机杂化介孔二氧化硅的分类及合成方法,重点介绍了该类材料作为吸附剂在环境保护中的应用,包括金属阳离子、含氧阴离子、有机污染物和气体的去除与回收.并展望了有机-无机杂化介孔二氧化硅的发展前景.

  6. SYNTHESIS OF CATALYSTS BY THE FUNCTIONALIZATION OF SILICA AND ITS APPLICATIONS

    Institute of Scientific and Technical Information of China (English)

    Yasuhiko Kurusu

    1999-01-01

    Hybrid organic-inorganic silica materials containing organic functional groups have been prepared by the reaction of activated silica with a silane coupling reagent such as N-(2-aminoethyl)3-aminopropyltrimethoxysilane. The hybrid silica was further modified by organic compounds having a bifunctional group. These modified hybrid silicas were used as catalysts for various nucleophilic reactions.And also, these were complexed with metallic ions for use as catalysts for oxygen oxidation of hydrocarbons.

  7. Rapid Preparation of Monolithic Columns for Capillary Electrochromatography Separation

    Institute of Scientific and Technical Information of China (English)

    Wen Jun GONG; Yi Jun ZHANG; Yu Ping ZHANG; Seong Ho CHOI

    2006-01-01

    Fritless packed silica gel columns were prepared using sol-gel technology. The part of a75 μm i.d. capillary was filled with a mixture of methacryloxypropyltrimethoxysilane, toluene and hydrochloric acid. Four different photoinitiators such as benzoin methyl ether, Irgacure 819,Irgacure 1700 and irgacure 1800 were added in the presence or absence of sodium dodecyl sulfate during the polymerization process. The above eight solutions were irradiated at 365 nm about5-10 min to prepare the porous monolithic sol-gel columns by a one-step process.

  8. Silica Nephropathy

    Directory of Open Access Journals (Sweden)

    N Ghahramani

    2010-06-01

    Full Text Available Occupational exposure to heavy metals, organic solvents and silica is associated with a variety of renal manifestations. Improved understanding of occupational renal disease provides insight into environmental renal disease, improving knowledge of disease pathogenesis. Silica (SiO2 is an abundant mineral found in sand, rock, and soil. Workers exposed to silica include sandblasters, miners, quarry workers, masons, ceramic workers and glass manufacturers. New cases of silicosis per year have been estimated in the US to be 3600–7300. Exposure to silica has been associated with tubulointerstitial disease, immune-mediated multisystem disease, chronic kidney disease and end-stage renal disease. A rare syndrome of painful, nodular skin lesions has been described in dialysis patients with excessive levels of silicon. Balkan endemic nephropathy is postulated to be due to chronic intoxication with drinking water polluted by silicates released during soil erosion. The mechanism of silica nephrotoxicity is thought to be through direct nephrotoxicity, as well as silica-induced autoimmune diseases such as scleroderma and systemic lupus erythematosus. The renal histopathology varies from focal to crescentic and necrotizing glomerulonephritis with aneurysm formation suggestive of polyarteritis nodosa. The treatment for silica nephrotoxicity is non-specific and depends on the mechanism and stage of the disease. It is quite clear that further research is needed, particularly to elucidate the pathogenesis of silica nephropathy. Considering the importance of diagnosing exposure-related renal disease at early stages, it is imperative to obtain a thorough occupational history in all patients with renal disease, with particular emphasis on exposure to silica, heavy metals, and solvents.

  9. Detachable strong cation exchange monolith, integrated with capillary zone electrophoresis and coupled with pH gradient elution, produces improved sensitivity and numbers of peptide identifications during bottom-up analysis of complex proteomes.

    Science.gov (United States)

    Zhang, Zhenbin; Yan, Xiaojing; Sun, Liangliang; Zhu, Guijie; Dovichi, Norman J

    2015-04-21

    A detachable sulfonate-silica hybrid strong cation-exchange monolith was synthesized in a fused silica capillary, and used for solid phase extraction with online pH gradient elution during capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) proteomic analysis. Tryptic digests were prepared in 50 mM formic acid and loaded onto the strong cation-exchange monolith. Fractions were eluted using a series of buffers with lower concentration but higher pH values than the 50 mM formic acid background electrolyte. This combination of elution and background electrolytes results in both sample stacking and formation of a dynamic pH junction and allows use of relatively large elution buffer volumes while maintaining reasonable peak efficiency and resolution. A series of five pH bumps were applied to elute E. coli tryptic peptides from the monolith, followed by analysis using CZE coupled to an LTQ-Orbitrap Velos mass spectrometer; 799 protein groups and 3381 peptides were identified from 50 ng of the digest in a 2.5 h analysis, which approaches the identification rate for this organism that was obtained with an Orbitrap Fusion. We attribute the improved numbers of peptide and protein identifications to the efficient fractionation by the online pH gradient elution, which decreased the complexity of the sample in each elution step and improved the signal intensity of low abundance peptides. We also performed a comparative analysis using a nanoACQUITY UltraPerformance LCH system. Similar numbers of protein and peptide identifications were produced by the two methods. Protein identifications showed significant overlap between the two methods, whereas peptide identifications were complementary.

  10. Preparation of organic/inorganic hybrid and hollow particles by catalytic deposition of silica onto core/shell heterocoagulates modified with poly[2-(N,N-dimethylamino)ethyl methacrylate].

    Science.gov (United States)

    Taniguchi, Tatsuo; Obi, Shun; Kamata, Yoshitada; Kashiwakura, Takuya; Kasuya, Masakatsu; Ogawa, Tatsuya; Kohri, Michinari; Nakahira, Takayuki

    2012-02-15

    The organic/inorganic hybrid particles PSt/P(St-CPEM)(θ)-g-PDMAEMA/SiO(2) were prepared by catalytic hydrolysis and subsequent polycondensation of tetraethoxysilane in the poly[2-(N,N-dimethylamino)ethyl methacrylate] (PDMAEMA) layers grafted on the PSt/P(St-CPEM)(θ) core/shell heterocoagulates. The micron-sized PSt core and the submicron-sized P(St-CPEM) shell particles bearing ATRP initiating groups were synthesized by dispersion polymerization of styrene (St) and emulsifier-free emulsion polymerization of St with 2-chloropropionyloxyethyl methacrylate (CPEM), respectively. The raspberry-shaped PSt/P(St-CPEM)(θ) heterocoagulates with a controlled surface coverage (θ=0.51, 0.81) were prepared by hydrophobic coagulation between the core and the shell particles in an aqueous NaCl solution near the T(g) of P(St-CPEM). Surface modification of heterocoagulates was carried out by ATRP of DMAEMA from the shell particles adsorbed on the core particles. Silica deposition was performed by simply adding tetraethoxysilane to a water/methanol dispersion of PSt/P(St-CPEM)(θ)-g-PDMAEMA. The SEM and TGA revealed that the resulting PSt/P(St-CPEM)(θ)-g-PDMAEMA/SiO(2) composites maintain a raspberry-like morphology after deposition of silica onto the PDMAEMA layer grafted on heterocoagulates. The micron-sized, raspberry-shaped or the submicron-sized, hole-structured silica hollow particles were obtained selectively by thermal decomposition of the PSt/P(St-CPEM)(θ)-g-PDMAEMA/SiO(2). The oriented particle array was fabricated by dropping anisotropically perforated silica particles onto a glass substrate settled at the bottom of a bottle filled with chloroform.

  11. One-pot preparation of silica-supported hybrid immobilized metal affinity adsorbent with macroporous surface based on surface imprinting coating technique combined with polysaccharide incorporated sol--gel process.

    Science.gov (United States)

    Li, Feng; Li, Xue-Mei; Zhang, Shu-Sheng

    2006-10-06

    A simple and reliable one-pot approach using surface imprinting coating technique combined with polysaccharide incorporated sol-gel process was established to synthesize a new organic-inorganic hybrid matrix possessing macroporous surface and functional ligand. Using mesoporous silica gel being a support, immobilized metal affinity adsorbent with a macroporous shell/mesoporous core structure was obtained after metal ion loading. In the prepared matrix, covalently bonded coating and morphology manipulation on silica gel was achieved by using one-pot sol-gel process starting from an inorganic precursor, -glycidoxypropyltrimethoxysiloxane (GPTMS), and a functional biopolymer, chitosan (CS) at the atmosphere of imprinting polyethylene glycol (PEG). Self-hydrolysis of GPTMS, self-condensation, and co-condensation of silanol groups (Si-OH) from siloxane and silica gel surface, and in situ covalent cross-linking of CS created an orderly coating on silica gel surface. PEG extraction using hot ammonium hydroxide solution gave a chemically and mechanically stabilized pore structure and deactivated residual epoxy groups. The prepared matrix was characterized by using X-ray energy dispersion spectroscopy (EDX), scanning electron microscopy (SEM) and mercury intrusion porosimetry. The matrix possessed a high capacity for copper ion loading. Protein adsorption performance of the new immobilized metal affinity adsorbent was evaluated by batch adsorption and column chromatographic experiment using bovine serum albumin (BSA) as a simple model protein. Under the optimized coating conditions, the obtained macroporous surface resulted in a fast kinetics and high capability for protein adsorption, while the matrix non-charged with metal ions offered a low non-specific adsorption.

  12. New monolith technology for automated anion-exchange purification of nucleic acids.

    Science.gov (United States)

    Thayer, J R; Flook, K J; Woodruff, A; Rao, S; Pohl, C A

    2010-04-15

    Synthetic nucleic acid analysis often employs pellicular anion-exchange (AE) chromatography because it supports very high efficiency separations while offering means to control secondary structure, retention and resolution by readily modifiable chromatographic conditions. However, these pellicular anion-exchange (pAE) phases do not offer capacity sufficient for lab-scale oligonucleotide (ON) purification. In contrast, monolithic phases produce fast separations at capacities exceeding their pellicular counterparts, but do not exhibit capacities typical of fully porous, bead-based, anion-exchangers. In order to further increase monolith capacity and obtain the selectivity and mass transfer characteristics of pellicular phases, a surface-functionalized monolith was coated with pAE nanobeads (latexes) usually employed on the pellicular DNAPac phase. The nanobead-coated monolith exhibited chromatographic behaviors typical of polymer AE phases. Based on this observation the monolithic substrate surface porosity and latex diameters were co-optimized to produce a hybrid monolith harboring capacity similar to that of fully porous bead-based phases and peak shape approaching that of the pAE phases. We tested the hybrid monolith on a variety of previously developed pAE capabilities including control of ON selectivity, resolution of derivatized ONs, the ability to resolve RNA ONs harboring aberrant linkages at different positions in a single sequence and separation of phosphorothioate diastereoisomers. We compared the yield and purity of an 8 mg ON sample purified on both the new hybrid monolith and a benchmark AE column based on fully porous monodisperse beads. This comparison included an assessment of the relative selectivities of both columns. Finally, we demonstrated the ability to couple AE ON separations with ESI-MS using an automated desalting protocol. This protocol is also useful for preparing ONs for other assays, such as enzyme treatments, that may be sensitive to

  13. Study of cross-linking reactions induced by gamma rays in hybrid membranes of Bisphenol-A-Polysulfone and precipitated silica; Estudo da formacao de ligacoes cruzadas por irradiacao gama em membranas hibridas de Polissulfona Bisfenol-A e silica precipitada

    Energy Technology Data Exchange (ETDEWEB)

    Furtado Filho, Acacio Antonio M., E-mail: facacio@ctex.eb.br [Laboratorio de Quimica Militar, CTEx, Rio de Janeiro, RJ (Brazil); Gomes, Ailton de S.; Lopes, Lea; Benzi, Marcia R. [Instituto de Macromoleculas Professora Eloisa Mano, UFRJ, Rio de Janeiro, RJ (Brazil)

    2011-07-01

    In this work the bisphenol-A-polysulfone (PSF) was sulfonated using trimethyl silyl chlorosulfonate [(CH{sub 3}){sub 3}SiSO{sub 3}Cl] as a mild sulfonating agent in a homogeneous solution of dichloroethane. The sulfonation reaction was confirmed by acid-base titration and FTIR-spectroscopy analysis. The hybrid membranes were obtained by casting the sulfonated bisphenol-A-polysulfone (SPSF) and precipitated silica Tixosil{sup R} 333 solutions in N-N-dimethylacetamide. Cross-linking in the hybrid membranes was obtained by irradiation, with doses ranging from 5 to 30 kGy using gamma ray from a {sup 60}Co source. The water uptake and the swelling of the membranes were estimated by measuring the change in weight between dry and wet conditions. The conductivity of the membranes in acid form was measured with the ac impedance technique using a PGSTAT30 frequency response analyzer. The hybrid cross-linked membranes have conductivity close to 10-1 S.cm{sup -1} at 100% RH and 80 deg C. Electrochemical performances, thermo-mechanical stability and low cost make this cross-linked SPSF hybrid membrane an attractive material for fuel cells using a proton exchange membrane. (author)

  14. Recent progress in design and hybridization of planar grating-based transceivers

    Science.gov (United States)

    Bidnyk, S.; Pearson, M.; Balakrishnan, A.; Gao, M.

    2007-06-01

    We report on recent progress in simulations, physical layout, fabrication and hybridization of planar grating-based transceivers for passive optical networks (PONs). Until recently, PON transceivers have been manufactured using bulk micro-optical components. Today, advancements in modeling and simulation techniques has made it possible to design complex elements in the same silica-on silicon PLC platform and create an alternative platform for manufacturing of bi-directional transceivers. In our chips we simulated an integrated chip that monolithically combined planar reflective gratings and cascaded Mach-Zehnder interferometers. We used a combination of the finite element method and beam propagation method to model cascaded interferometers with enhanced coupling coefficients. Our simulations show that low-diffraction order planar reflective gratings, designed for small incidence and reflection angles, possess the required dispersion strength to meet the PON specifications. Subsequently, we created structures for passive alignment and hybridized photodetectors and lasers. We believe that advancements in simulation of planar lightwave circuits with embedded planar reflective gratings will result in displacement of the thin-film filters (TFFs) technology in many applications that require a high degree of monolithic and hybrid integration.

  15. Mixed-Matric Membranes for CO2 and H2 Gas Separations Using Metal-Organic Framework and Mesoporus Hybrid Silicas

    Energy Technology Data Exchange (ETDEWEB)

    Inga Musselman; Kenneth Balkus, Jr.; John Ferraris

    2009-01-07

    In this work, we have investigated the separation performance of polymer-based mixed-matrix membranes containing metal-organic frameworks and mesoporous hybrid silicas. The MOF/Matrimid{reg_sign} and MOP-18/Matrimid{reg_sign} membranes exhibited improved dispersion and mechanical strength that allowed high additive loadings with reduced aggregation, as is the case of the 80 wt% MOP-18/Matrimid{reg_sign} and the 80% (w/w) Cu-MOF/Matrimid{reg_sign} membranes. Membranes with up to 60% (w/w) ZIF-8 content exhibited similar mechanical strength and improved dispersion. The H{sub 2}/CO{sub 2} separation properties of MOF/Matrimid{reg_sign} mixed-matrix membranes was improved by either keeping the selectivity constant and increasing the permeability (MOF-5, Cu-MOF) or by improving both selectivity and permeability (ZIF-8). In the case of MOF-5/Matrimid{reg_sign} mixed-matrix membranes, the H{sub 2}/CO{sub 2} selectivity was kept at 2.6 and the H{sub 2} permeability increased from 24.4 to 53.8 Barrers. For the Cu-MOF/Matrimid{reg_sign} mixed-matrix membranes, the H{sub 2}/CO{sub 2} selectivity was kept at 2.05 and the H{sub 2} permeability increased from 17.1 to 158 Barrers. These two materials introduced porosity and uniform paths that enhanced the gas transport in the membranes. When ZIF-8/Matrimid{reg_sign} mixed-matrix membranes were studied, the H{sub 2}/CO{sub 2} selectivity increased from 2.9 to 4.4 and the permeability of H{sub 2} increased from 26.5 to 35.8 Barrers. The increased H{sub 2}/CO{sub 2} selectivity in ZIF-8/Matrimid{reg_sign} membranes was explained by the sieving effect introduced by the ZIF-8 crystals (pore window 0.34 nm) that restricted the transport of molecules larger than H{sub 2}. Materials with microporous and/or mesoporous cavities like carbon aerogel composites with zeolite A and zeolite Y, and membranes containing mesoporous ZSM-5 showed sieving effects for small molecules (e.g. H{sub 2} and CO{sub 2}), however, the membranes were most

  16. Silica- and germania-based dual-ligand sol-gel organic-inorganic hybrid sorbents combining superhydrophobicity and π-π interaction. The role of inorganic substrate in sol-gel capillary microextraction.

    Science.gov (United States)

    Seyyal, Emre; Malik, Abdul

    2017-04-29

    Principles of sol-gel chemistry were utilized to create silica- and germania-based dual-ligand surface-bonded sol-gel coatings providing enhanced performance in capillary microextraction (CME) through a combination of ligand superhydrophobicity and π-π interaction. These organic-inorganic hybrid coatings were prepared using sol-gel precursors with bonded perfluorododecyl (PF-C12) and phenethyl (PhE) ligands. Here, the ability of the PF-C12 ligand to provide enhanced hydrophobic interaction was advantageously combined with π-π interaction capability of the PhE moiety to attain the desired sorbent performance in CME. The effect of the inorganic sorbent component on microextraction performance of was explored by comparing microextraction characteristics of silica- and germania-based sol-gel sorbents. The germania-based dual-ligand sol-gel sorbent demonstrated superior CME performance compared to its silica-based counterpart. Thermogravimetric analysis (TGA) of the created silica- and germania-based dual-ligand sol-gel sorbents suggested higher carbon loading on the germania-based sorbent. This might be indicative of more effective condensation of the organic ligand-bearing sol-gel-active chemical species to the germania-based sol-gel network (than to its silica-based counterpart) evolving in the sol solution. The type and concentration of the organic ligands were varied in the sol-gel sorbents to fine-tune extraction selectivity toward different classes of analytes. Specific extraction (SE) values were used for an objective comparison of the prepared sol-gel CME sorbents. The sorbents with higher content of PF-C12 showed remarkable affinity for aliphatic hydrocarbons. Compared to their single-ligand sol-gel counterparts, the dual-ligand sol-gel coatings demonstrated significantly superior CME performance in the extraction of alkylbenzenes, providing up to ∼65.0% higher SE values. The prepared sol-gel CME coatings provided low ng L(-1) limit of detections (LOD

  17. Monolithic pixels on moderate resistivity substrate and sparsifying readout architecture

    Science.gov (United States)

    Giubilato, P.; Battaglia, M.; Bisello, D.; Caselle, M.; Chalmet, P.; Demaria, L.; Ikemoto, Y.; Kloukinas, K.; Mansuy, S. C.; Mattiazzo, S.; Marchioro, A.; Mugnier, H.; Pantano, D.; Potenza, A.; Rivetti, A.; Rousset, J.; Silvestrin, L.; Snoeys, W.

    2013-12-01

    The LePix projects aim realizing a new generation monolithic pixel detectors with improved performances at lesser cost with respect to both current state of the art monolithic and hybrid pixel sensors. The detector is built in a 90 nm CMOS process on a substrate of moderate resistivity. This allows charge collection by drift while maintaining the other advantages usually offered by MAPS, like having a single piece detector and using a standard CMOS production line. The collection by drift mechanism, coupled to the low capacitance design of the collecting node made possible by the monolithic approach, provides an excellent signal to noise ratio straight at the pixel cell together with a radiation tolerance far superior to conventional un-depleted MAPS. The excellent signal-to-noise performance is demonstrated by the device ability to separate the 6 keV 55Fe double peak at room temperature. To achieve high granularity (10-20 μm pitch pixels) over large detector areas maintaining high readout speed, a completely new compressing architecture has been devised. This architecture departs from the mainstream hybrid pixel sparsification approach, which uses in-pixel logic to reduce data, by using topological compression to minimize pixel area and power consumption.

  18. Thiol-yne Click Adamantane Monolithic Stationary Phase for Capillary Electrochromatography

    Institute of Scientific and Technical Information of China (English)

    Dao, Thi Thu Hien; Guerrouache, Mohamed; Carbonnier, Benjamin

    2012-01-01

    A porous crosslinked organic polymer based on N-acryloxysuccinimide (NAS) and ethylene dimethacrylate (EDMA) was prepared inside 75 μm i.d. fused silica capillary as functionalizable monolithic stationary phase for electrochromatographic applications. Succinimide groups on the monolith surface provide reactive sites able to re- act readily through standard electrophile-nucleophile chemistry. Propargylamine was used to prepare alkyne func- tionalized poly(NAS-co-EDMA). Onto this thiol-reactive polymer surface was grafted adamantane units via a photochemically-driven addition reaction. Chemical characterization was performed in situ after each synthetic step by means of Raman spectroscopy and grafting kinetics was investigated to ensure quantitative grafting of 1-adamantanethiol. The as-designed monolithic stationary phase exhibited typical reversed-phase separation mechanism as evidenced by the linear increase of the logarithm of retention factor of neutral aromatic solutes with the increase of the aqueous buffer content in the mobile phase.

  19. In situ sol-gel preparation of porous alumina monoliths for chromatographic separations of adenosine phosphates.

    Science.gov (United States)

    Zajickova, Zuzana; Rubi, Emir; Svec, Frantisek

    2011-06-03

    A method enabling the in situ preparation of porous alumina monoliths within 100 μm i.d. fused silica capillaries has been developed. These monoliths were prepared using the sol-gel process from a mixture consisting of an inorganic aluminum salt, a porogen, an epoxide, and a solvent. We investigated the effects of varying the preparation conditions on the physical characteristics of the monoliths with respect to their potential application in chromatographic separations. The best columns were obtained from a mixture of aluminum chloride hexahydrate, N,N-dimethylformamide, water, ethanol and propylene oxide. Adenosine phosphates were then separated in the optimized column with retention increasing according to number of phosphate functionalities.

  20. InP-PD integration on silica-based PLC for QPSK receiver

    Science.gov (United States)

    Itoh, Mikitaka; Hashimoto, Toshikazu

    2013-03-01

    We review our recent progress on the heterogeneous integration of high-speed InP photodiodes (PDs) on a silica-based planar lightwave circuit (PLC) with the goal of realizing a small photonic integrated circuit (PIC) device with excellent performance. Heterogeneous integration technology is a combination of monolithic InP fabrication and angled micro-mirror etching processes, and provides low-loss optical coupling between them without any complicated optical alignment. Also, by employing 2.5%-Δ waveguides with a bending radius of 1 mm, we can reduce the chip size required for compact PIC devices. We demonstrated a dual-polarization quadrature-phase-shift-keying (DP-QPSK) coherent detector composed of a variable optical attenuator (VOA), a polarization beam splitter (PBS), eight high-speed PDs, two 90-degree optical hybrids (OHs) and micro-mirrors. Heterogeneous technology on silica-based PLCs will be an attractive way to provide compact high performance PICs for future photonic networks.

  1. Functional Films from Silica/Polymer Nanoparticles

    Directory of Open Access Journals (Sweden)

    Tânia Ribeiro

    2014-05-01

    Full Text Available High performance functional coatings, based on hybrid organic/inorganic materials, are being developed to combine the polymer flexibility and ease of processing with the mechanical properties and versatility of inorganic materials. By incorporating silica nanoparticles (SiNPs in the polymeric matrices, it is possible to obtain hybrid polymer films with increased tensile strength and impact resistance, without decreasing the flexural properties of the polymer matrix. The SiNPs can further be used as carriers to impart other functionalities (optical, etc. to the hybrid films. By using polymer-coated SiNPs, it is possible to reduce particle aggregation in the films and, thus, achieve more homogeneous distributions of the inorganic components and, therefore, better properties. On the other hand, by coating polymer particles with silica, one can create hierarchically structured materials, for example to obtain superhydrophobic coatings. In this review, we will cover the latest developments in films prepared from hybrid polymer/silica functional systems.

  2. Piezoresistive Sensors Development Using Monolithic CMOS MEMS Technology

    Directory of Open Access Journals (Sweden)

    A. Chaehoi

    2011-04-01

    Full Text Available This paper presents the development of a monolithic CMOS-MEMS platform under the iDesign and SemeMEMS projects with the aim of jointly providing an open access “one-stop-shop” design and prototyping facility for integrated CMOS-MEMS. This work addresses the implementation of a 3-axis accelerometer and a pressure sensor using Semefab’s in-house 2-poly 1-metal CMOS process on a 380/4/15 μm SOI wafer; the membrane and the proof mass being micromachined using double-sided Deep Reactive Ion Etching (DRIE. This monolithic approach promises, in high volume production and using low complexity processes, a dramatic cost reduction over hybrid sensors. Furthermore, the embedded signal conditioning and the low-noise level in polysilicon gauges enables high performance to be achieved by implementing dedicated on-chip amplification and filtering circuitry.

  3. Silica research in Glasgow

    CERN Document Server

    Barr, B W; Casey, M M; Clubley, D; Crooks, D R M; Danzmann, K; Elliffe, E J; Gossler, S; Grant, A; Grote, H; Heptonstall, A; Hough, J; Jennrich, O; Lück, H B; McIntosh, S A; Newton, G P; Palmer, D A; Plissi, M V; Robertson, D I; Robertson, N A; Rowan, S; Skeldon, K D; Sneddon, P; Strain, K A; Torrie, C I; Ward, H; Willems, P A; Willke, B; Winkler, W

    2002-01-01

    The Glasgow group is involved in the construction of the GEO600 interferometer as well as in R and D activity on technology for advanced gravitational wave detectors. GEO600 will be the first GW detector using quasi-monolithic silica suspensions in order to decrease thermal noise significantly with respect to steel wire suspensions. The results concerning GEO600 suspension mounting and performance will be shown in the first section. Section 2 is devoted to the present results from the direct measurement of thermal noise in mirrors mounted in the 10 m interferometer in Glasgow which has a sensitivity limit of 4 x 10 sup - sup 1 sup 9 m Hz sup - sup 1 sup / sup 2 above 1 kHz. Section 3 presents results on the measurements of coating losses. R and D activity has been carried out to understand better how thermal noise in the suspensions affects the detector sensitivity, and in section 4 a discussion on the non-linear thermoelastic effect is presented.

  4. Preparation of a novel ionic hybrid stationary phase by non-covalent functionalization of single-walled carbon nanotubes with amino-derivatized silica gel for fast HPLC separation of aromatic compounds.

    Science.gov (United States)

    Aral, Hayriye; Çelik, K Serdar; Aral, Tarık; Topal, Giray

    2016-03-01

    Single-walled carbon nanotubes (SWCNTs) were immobilized on spherical silica gel with a 4-μm average particle size and a 60-Å average pore size. The amino-derivatized silica gel was non-covalently coated with carboxylated SWCNTs to preserve the structure of the nanotubes and their physico-chemical properties. The novel ionic hybrid stationary phase was characterized by scanning electron microscopy (SEM), infra-red (IR) spectroscopy and elemental analysis, and then, it was used to fill an empty 150×4.6mm(2) high-performance liquid chromatography (HPLC) column. Chromatographic parameters, such as the theoretical plate number, retention factor and peak asymmetry factor, and analytical parameters, such as the limit of detection (LOD), limit of quantification (LOQ), linear range, calibration equation, and R(2) value, and quantitative analysis parameters were calculated for all of the analytes. Using different mobile phases, five different classes of aromatic hydrocarbons were separated in a very short analysis time of 4-8min. Furthermore, a high theoretical plate number (up to 25000) and an excellent peak asymmetry factor (1.0) were obtained. The results showed that the surface of the SWNTs had very strong interactions with aromatic groups, therefore providing high selectivity for the separation of different classes of aromatic compounds. This study indicates that SWCNTs enable the extension of the application range of the newly prepared stationary phases for the fast separation of aromatic compounds by HPLC.

  5. In situ Fabrication of Monolithic Copper Azide

    Science.gov (United States)

    Li, Bing; Li, Mingyu; Zeng, Qingxuan; Wu, Xingyu

    2016-04-01

    Fabrication and characterization of monolithic copper azide were performed. The monolithic nanoporous copper (NPC) with interconnected pores and nanoparticles was prepared by decomposition and sintering of the ultrafine copper oxalate. The preferable monolithic NPC can be obtained through decomposition and sintering at 400°C for 30 min. Then, the available monolithic NPC was in situ reacted with the gaseous HN3 for 24 h and the monolithic NPC was transformed into monolithic copper azide. Additionally, the copper particles prepared by electrodeposition were also reacted with the gaseous HN3 under uniform conditions as a comparison. The fabricated monolithic copper azide was characterized by Fourier transform infrared (FTIR), inductively coupled plasma-optical emission spectrometry (ICP-OES), and differential scanning calorimetry (DSC).

  6. Compact silica-on-silicon planar lightwave circuits for high speed optical signal processing

    Science.gov (United States)

    Callender, C. L.; Dumais, P.; Blanchetiere, C.; Jacob, S.; Ledderhof, C.; Smelser, C. W.; Yadav, K.; Albert, J.

    2012-02-01

    Silica-on-silicon planar lightwave circuit (PLC) technology is well established and provides a low loss and stable photonic device platform. However, limitations in size and integration of active components remain. Engineering of the layer structure in silica PLCs to achieve high-index contrast, compact device architectures and monolithically integrated optical nonlinearities is described. Modeling of properties of doped-silica layers provides a design strategy for optimization of waveguide loss and birefringence. Optical nonlinearities in poled silica layers have been demonstrated, and recent work to incorporate these into functional device structures and exploit them for high speed modulation is reported.

  7. Polymer monolith microextraction using poly(butyl methacrylate-co-1,6-hexanediol ethoxylate diacrylate) monolithic sorbent for determination of phenylurea herbicides in water samples.

    Science.gov (United States)

    Lin, Shu-Ling; Wu, Yu-Ru; Fuh, Ming-Ren

    2016-01-15

    In this study, recently developed 1,6-hexanediol ethoxylate diacrylate (HEDA)-based polymeric monoliths were utilized as sorbents for efficient extraction of phenylurea herbicides (PUHs) from water samples. The HEDA-based monolithic sorbents were prepared in a fused silica capillary (0.7mm i.d., 4.5-cm long) for polymer monolith microextraction (PMME). The experimental parameters of PMME microextraction including sample loading speed, pH of sample solution, composition of elution solvent, and addition of salt were optimized to efficiently extract PUHs from environmental water samples. The extracted PUHs were determined using ultra-high performance liquid chromatography (UHPLC) with UV-photodiode array detection. The extraction recoveries for PUHs-spiked water samples were 91.1-108.1% with relative standard deviations lower than 5%. The linearity range was 0.025-25ngmL(-1) for each PUH and the detection limits of PUHs were estimated at 0.006-0.019ng mL(-1). In addition, good intra-day/inter-day precision (0.1-8.7%/0.2-8.9%) and accuracy (92.0-108.0%/96.5-105.2%) of the proposed method were obtained. The extraction capacity of the monolith-filled capillary was also determined to be approximately 1μg. Moreover, each monolith-filled capillary could be reused up to 8 times without carry-over. According to the European Union regulations, the allowed permissible limit of any single herbicide in drinking water is 0.1ng mL(-1). This permissible level fell in the linear range examined in this study. In addition, the proposed method provided detection limits lower than the allowed permissible level, which demonstrated the feasibility of utilizing the HEDA-based monolithic sorbent to perform PMME for determining contaminants, such as PUHs, in environmental application.

  8. Advances in the development of organic polymer monolithic columns and their applications in food analysis--a review.

    Science.gov (United States)

    Jandera, Pavel

    2013-10-25

    Monolithic continuous separation media are gradually finding their way to sample pre-treatment, isolation, enrichment and final analytical separations of a plethora of compounds, occurring as food components, additives or contaminants, including pharmaceuticals, pesticides and toxins, which have traditionally been the domain of particulate chromatographic materials. In the present review, recent advances in the technology of monolithic columns and the applications in food analysis are addressed. Silica-based monoliths are excellent substitutes to conventional particle-packed columns, improving the speed of analysis for low-molecular weight compounds, due to their excellent efficiency and high permeability. These properties have been recently appreciated in two-dimensional HPLC, where the performance in the second dimension is of crucial importance. Organic-polymer monoliths in various formats provide excellent separations of biopolymers. Thin monolithic disks or rod columns are widely employed in isolation, purification and pre-treatment of sample containing proteins, peptides or nucleic acid fragments. Monolithic capillaries were originally intended for use in electrochromatography, but are becoming more frequently used for capillary and micro-HPLC. Monoliths are ideal highly porous support media for immobilization or imprinting template molecules, to provide sorbents for shape-selective isolation of target molecules from various matrices occurring in food analysis. The separation efficiency of organic polymer monoliths for small molecules can be significantly improved by optimization of polymerization approach, or by post-polymerization modification. This will enable full utilization of a large variety of available monomers to prepare monoliths with chemistry matching the needs of selectivity of separations of various food samples containing even very polar or ionized compounds.

  9. Monolithic pixels on moderate resistivity substrate and sparsifying readout architecture

    CERN Document Server

    Giubilato, P; Snoeys, W; Bisello, D; Marchioro, A; Battaglia, M; Demaria, L; Mansuy, S C; Pantano, D; Rousset, J; Mattiazzo, S; Kloukinas, K; Potenza, A; Ikemoto, Y; Rivetti, A; Chalmet, P; Mugnier, H; Silvestrin, L

    2013-01-01

    The LePix projects aim realizing a new generation monolithic pixel detectors with improved performances at lesser cost with respect to both current state of the art monolithic and hybrid pixel sensors. The detector is built in a 90 nm CMOS process on a substrate of moderate resistivity. This allows charge collection by drift while maintaining the other advantages usually offered by MAPS, like having a single piece detector and using a standard CMOS production line. The collection by drift mechanism, coupled to the low capacitance design of the collecting node made possible by the monolithic approach, provides an excellent signal to noise ratio straight at the pixel cell together with a radiation tolerance far superior to conventional un-depleted MAPS. The excellent signal-to-noise performance is demonstrated by the device ability to separate the 6 keV Fe-55 double peak at room temperature. To achieve high granularity (10-20 mu m pitch pixels) over large detector areas maintaining high readout speed, a complet...

  10. Monolithic Fuel Fabrication Process Development

    Energy Technology Data Exchange (ETDEWEB)

    C. R. Clark; N. P. Hallinan; J. F. Jue; D. D. Keiser; J. M. Wight

    2006-05-01

    The pursuit of a high uranium density research reactor fuel plate has led to monolithic fuel, which possesses the greatest possible uranium density in the fuel region. Process developments in fabrication development include friction stir welding tool geometry and cooling improvements and a reduction in the length of time required to complete the transient liquid phase bonding process. Annealing effects on the microstructures of the U-10Mo foil and friction stir welded aluminum 6061 cladding are also examined.

  11. Pressure drop in CIM disk monolithic columns.

    Science.gov (United States)

    Mihelic, Igor; Nemec, Damjan; Podgornik, Ales; Koloini, Tine

    2005-02-11

    Pressure drop analysis in commercial CIM disk monolithic columns is presented. Experimental measurements of pressure drop are compared to hydrodynamic models usually employed for prediction of pressure drop in packed beds, e.g. free surface model and capillary model applying hydraulic radius concept. However, the comparison between pressure drop in monolith and adequate packed bed give unexpected results. Pressure drop in a CIM disk monolithic column is approximately 50% lower than in an adequate packed bed of spheres having the same hydraulic radius as CIM disk monolith; meaning they both have the same porosity and the same specific surface area. This phenomenon seems to be a consequence of the monolithic porous structure which is quite different in terms of the pore size distribution and parallel pore nonuniformity compared to the one in conventional packed beds. The number of self-similar levels for the CIM monoliths was estimated to be between 1.03 and 2.75.

  12. Copper nanoparticles supported on permeable monolith with carboxylic acid surface functionality: Stability and catalytic properties under reductive conditions

    Energy Technology Data Exchange (ETDEWEB)

    Poupart, Romain; Le Droumaguet, Benjamin, E-mail: ledroumaguet@icmpe.cnrs.fr; Guerrouache, Mohamed; Carbonnier, Benjamin, E-mail: carbonnier@icmpe.cnrs.fr

    2015-08-01

    This work reported on the immobilization of copper metallic nanoparticles at the interface of mercaptosuccinic acid-functionalized N-acryloxysuccinimide-based monoliths. Upon photochemically-mediated free radical copolymerization of N-acryloxysuccinimide reactive monomer with ethylene glycol dimethacrylate cross-linker, reactive monoliths were obtained. Nucleophilic substitution of the N-hydroxysuccinimide moieties with allylamine, allowed for the synthesis of an olefin-functionalized monolith, as demonstrated by Raman spectroscopy. Mercaptosuccinic acid was anchored at the surface of the porous polymeric material through photochemically-driven thiol-ene “click” addition. In a final step, adsorption of copper nanoparticles at the surface of the resulting carboxylic acid functionalized monolith was achieved via two distinct pathways. It was either realized by percolation of a suspension of pre-formed copper nanoparticles through the capillary or by in situ reduction of Cu{sup (II)}Br{sub 2} salt solution preliminary flown through the monolith. After characterization of the resulting hybrids by scanning electron microscopy and energy-dispersive X-ray spectroscopy, investigations were further pursued regarding the catalytic behavior of such hybrid materials. The possibility to reduce 2-nitrophenol into the corresponding 2-aminophenol within a few minutes via a flow-through process inside the hybrid monolithic capillary was notably successfully demonstrated. - Graphical abstract: Display Omitted - Highlights: • Monolithic micro-reactors with surface immobilized copper nanoparticle for flow through catalytic processes. • Porous polymer-stabilized copper nanoparticles. • Photothiol-ene click chemistry for the effective surface functionalization of porous monolithic polymers. • Surface adsorption of copper nanoparticles through in-situ and ex-situ strategies.

  13. Collagen-biomorphic porous carbon nanofiber monoliths: Biosilicification-assisted sustainable synthesis and application in Li-S battery

    Science.gov (United States)

    Hu, Wen; Shen, Tao; Hou, Hongying; Gan, Guoyou; Zheng, Biju; Li, Fengxian; Yi, Jianhong

    2016-12-01

    Monolithic carbon has been synthesized via a sustainable biomimetic route utilizing intrafibrillar silicified collagen sponge as precursor and morphogenesis template. The mineralized silica in the biohybrid prevents collapse of the carbon during pyrolysis. Upon biosilica removal results show that the carbon monoliths inherit the porous fiber structure of the mother collagen. The carbon nanofiber framework facilitates the construction of a high electrical conductive pathway, while the internal spaces developed among the intertwined fibrillar network and pores within nanofiber walls offer room for sulfur storage. The as-obtained carbon-sulfur cathode exhibits an accessible discharge capacity approaching 800mAh g-1 in Li-S battery.

  14. Prospect of Thermal Insulation by Silica Aerogel: A Brief Review

    Science.gov (United States)

    Hasan, Mohammed Adnan; Sangashetty, Rashmi; Esther, A. Carmel Mary; Patil, Sharanabasappa B.; Sherikar, Baburao N.; Dey, Arjun

    2017-10-01

    Silica aerogel is a unique ultra light weight nano porous material which offers superior thermal insulation property as compared to the conventional thermal insulating materials. It can be applied not only for ground and aerospace applications but also in low and high temperatures and pressure regimes. Aerogel granules and monolith are synthesized by the sol-gel route while aerogel based composites are fabricated by the reinforcement of fibers, particle and opacifiers. Due to the characteristic brittleness (i.e., poor mechanical properties) of monolith or bulk aerogel, it is restricted in several applications. To improve the mechanical integrity and flexibility, usually different fibers are reinforced with aerogel and hence it can be used as flexible thermal insulation blankets. Further, to achieve effective thermal insulation behaviour particularly at high temperature, often opacifiers are doped with silica aerogel. In the present brief review, the prospects of bulk aerogel and aerogel based composites are discussed for the application of thermal insulation and thermal stability.

  15. Graphene-supported metal oxide monolith

    Energy Technology Data Exchange (ETDEWEB)

    Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Biener, Monika A.; Wang, Yinmin; Ye, Jianchao; Tylski, Elijah

    2017-01-10

    A composition comprising at least one graphene-supported metal oxide monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds, wherein the graphene sheets are coated by at least one metal oxide such as iron oxide or titanium oxide. Also provided is an electrode comprising the aforementioned graphene-supported metal oxide monolith, wherein the electrode can be substantially free of any carbon-black and substantially free of any binder.

  16. Graphene-supported metal oxide monolith

    Science.gov (United States)

    Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Biener, Monika A.; Wang, Yinmin; Ye, Jianchao; Tylski, Elijah

    2017-01-10

    A composition comprising at least one graphene-supported metal oxide monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds, wherein the graphene sheets are coated by at least one metal oxide such as iron oxide or titanium oxide. Also provided is an electrode comprising the aforementioned graphene-supported metal oxide monolith, wherein the electrode can be substantially free of any carbon-black and substantially free of any binder.

  17. Radiation-induced polymerization and grafting of {beta}(-)pinene on silica surface

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, Franco [Lupi Chemical Research Institute, Via Casilina 1626/A, 00133 Rome (Italy)], E-mail: cdcata@flashnet.it; Ursini, Ornella; Lilla, Edo; Angelini, Giancarlo [CNR, Institute of Chemical Metodologies, Area della Ricerca di Roma 1, Monterotondo Scalo, Rome (Italy)

    2008-05-15

    Poly-{beta}-pinene (pBp) was obtained on silica surface by {gamma} radiation-induced polymerization of {beta}(-)pinene in presence of silica gel with a specific surface area of 300 m{sup 2}/g. Different radiation doses were employed in the range 50-332 kGy. The pBp-silica hybrid samples obtained have been characterized by FT-IR spectroscopy and the amount of pBp on silica surface has been determined both by gravimetric and TGA measurements. The fraction of pBp chemically grafted on silica surface has been determined by the extraction of the pBp-silica hybrid with boiling toluene and was found to be 10-20% of the total pBp formed on silica surface. The optical activity of pBp extracted from the hybrid was studied by polarimetric measurements and found slightly lower than the typical specific optical rotation of pBp polymerized in bulk with radiation. The thermal stability of the pBp-silica hybrid materials was studied by thermogravimetric and differential thermal analysis. The results show lower thermal stability for the pBp-silica hybrid in comparison to pure pBp. Evidently, silica catalyzes the thermal decomposition of pBp at lower temperatures. Use of the pBp-silica hybrid as stationary phase for liquid chromatography for chiral separations has been proposed.

  18. Inverted opal luminescent Ce-doped silica glasses

    Directory of Open Access Journals (Sweden)

    R. Scotti

    2006-01-01

    Full Text Available Inverted opal Ce-doped silica glasses (Ce : Si molar ratio 1 ⋅ 10−3 were prepared by a sol-gel method using opals of latex microspheres as templates. The rare earth is homogeneously dispersed in silica host matrix, as evidenced by the absence of segregated CeO2, instead present in monolithic Ce-doped SG with the same cerium content. This suggests that the nanometric dimensions of bridges and junctions of the host matrix in the inverted opal structures favor the RE distribution avoiding the possible segregation of CeO2.

  19. Application of a hybrid ordered mesoporous silica as sorbent for solid-phase multi-residue extraction of veterinary drugs in meat by ultra-high-performance liquid chromatography coupled to ion-trap tandem mass spectrometry.

    Science.gov (United States)

    Casado, Natalia; Morante-Zarcero, Sonia; Pérez-Quintanilla, Damián; Sierra, Isabel

    2016-08-12

    A quick, sensitive and selective analytical reversed-phase multi-residue method using ultra-high performance liquid chromatography coupled to an ion-trap mass spectrometry detector (UHPLC-IT-MS/MS) operating in both positive and negative ion mode was developed for the simultaneous determination of 23 veterinary drug residues (β-blockers, β-agonists and Non-Steroidal Anti-inflammatory Drugs (NSAIDs)) in meat samples. The sample treatment involved a liquid-solid extraction followed by a solid-phase extraction (SPE) procedure. SBA-15 type mesoporous silica was synthetized and modified with octadecylsilane, and the resulting hybrid material (denoted as SBA-15-C18) was applied and evaluated as SPE sorbent in the purification of samples. The materials were comprehensively characterized, and they showed a high surface area, high pore volume and a homogeneous distribution of the pores. Chromatographic conditions and extraction procedure were optimized, and the method was validated according to the Commission Decision 2002/657/EC. The method detection limits (MDLs) and the method quantification limits (MQLs) were determined for all the analytes in meat samples and found to range between 0.01-18.75μg/kg and 0.02-62.50μg/kg, respectively. Recoveries for 15 of the target analytes ranged from 71 to 98%. In addition, for comparative purpose SBA-15-C18 was evaluated towards commercial C18 amorphous silica. Results revealed that SBA-15-C18 was clearly more successful in the multi-residue extraction of the 23 mentioned analytes with higher recovery values. The method was successfully tested to analyze prepacked preparations of mince bovine meat. Traces of propranolol, ketoprofen and diclofenac were detected in some samples.

  20. Evaluation of performance of three different hybrid mesoporous solids based on silica for preconcentration purposes in analytical chemistry: From the study of sorption features to the determination of elements of group IB.

    Science.gov (United States)

    Kim, Manuela Leticia; Tudino, Mabel Beatríz

    2010-08-15

    Several studies involving the physicochemical interaction of three silica based hybrid mesoporous materials with metal ions of the group IB have been performed in order to employ them for preconcentration purposes in the determination of traces of Cu(II), Ag(I) and Au(III). The three solids were obtained from mesoporous silica functionalized with 3-aminopropyl (APS), 3-mercaptopropyl (MPS) and N-[2-aminoethyl]-3-aminopropyl (NN) groups, respectively. Adsorption capacities for Au, Cu and Ag were calculated using Langmuir's isotherm model and then, the optimal values for the retention of each element onto each one of the solids were found. Physicochemical data obtained under thermodynamic equilibrium and under kinetic conditions - imposed by flow through experiments - allowed the design of simple analytical methodologies where the solids were employed as fillings of microcolumns held in continuous systems coupled on-line to an atomic absorption spectrometry. In order to control the interaction between the filling and the analyte at short times (flow through conditions) and thus, its effect on the analytical signal and the presence of interferences, the initial adsorption velocities were calculated using the pseudo second order model. All these experiments allowed the comparison of the solids in terms of their analytical behaviour at the moment of facing the determination of the three elements. Under optimized conditions mainly given by the features of the filling, the analytical methodologies developed in this work showed excellent performances with limits of detection of 0.14, 0.02 and 0.025 microg L(-1) and RSD % values of 3.4, 2.7 and 3.1 for Au, Cu and Ag, respectively. A full discussion of the main findings on the interaction metal ions/fillings will be provided. The analytical results for the determination of the three metals will be also presented.

  1. Carbon nanomaterials in silica aerogel matrices

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, Christopher E [Los Alamos National Laboratory; Chavez, Manuel E [Los Alamos National Laboratory; Duque, Juan G [Los Alamos National Laboratory; Gupta, Gautam [Los Alamos National Laboratory; Doorn, Stephen K [Los Alamos National Laboratory; Dattelbaum, Andrew M [Los Alamos National Laboratory; Obrey, Kimberly A D [Los Alamos National Laboratory

    2010-01-01

    Silica aerogels are ultra low-density, high surface area materials that are extremely good thermal insulators and have numerous technical applications. However, their mechanical properties are not ideal, as they are brittle and prone to shattering. Conversely, single-walled carbon nanotubes (SWCNTs) and graphene-based materials, such as graphene oxide, have extremely high tensile strength and possess novel electronic properties. By introducing SWCNTs or graphene-based materials into aerogel matrices, it is possible to produce composites with the desirable properties of both constituents. We have successfully dispersed SWCNTs and graphene-based materials into silica gels. Subsequent supercritical drying results in monolithic low-density composites having improved mechanical properties. These nanocomposite aerogels have great potential for use in a wide range of applications.

  2. Preparation and application of comb-like fluorosilicon copolymer/nano silica hybrid%纳米SiO2杂化梳状氟硅共聚物的合成与性能研究

    Institute of Scientific and Technical Information of China (English)

    郝丽芬; 许伟; 安秋凤

    2015-01-01

    Comb- like perfluoroalkyl ester/trifluoropropyl/ethoxy silane containing polysiloxanes (FPFAS) in-termediate was prepared through hydrosilylation and ring- opening reaction, which was reacted with silica sols via in situ condensation to produce comb- like fluorosilicon copolymer/nano silica hybrid (FPFAS- SiO2). Super-hydrophobic cotton fabric with good soft handle and air permeability was fabricated via simple dip- coating method. IR, XPS, FESEM and contact angle tester were utilized to characterize its structure, morphology and application properties. The results indicated that the product had the due structure. Superhydrophobicity of the treated fabric was influenced by the particle diameter of nano silica. While mass concentration of the FP-FAS- SiO2 in ethyl acetate solution was 0.5%, water contact angle and rol- off angle on the treated fabric sur-face were 163.5° and 7°, respectively. The treated cotton fabric possessed favorable air permeability and soft-ness. A micro/nano multiscale composite film on the fiber surface could be clearly observed by FESEM.%用硅氢化加成和开环反应先制得梳状结构的全氟酯基/三氟丙基/硅乙氧基改性聚硅氧烷(FPFAS)中间体.然后利用硅乙氧基与硅溶胶间的原位缩合反应,制得了纳米SiO2梳状氟硅共聚物(FPFAS-SiO2).并用一步浸渍法处理棉织物构筑了兼具柔软、良好透气性的超疏水织物.用IR、XPS、FESEM、接触角测量仪等对产物结构、膜形貌及应用性能进行研究.结果表明,产物具有预期结构.纳米SiO2粒径影响织物的超疏水性能,当FPFAS-SiO2溶液用量为0.5%,整理后织物表面的水静态接触角和滚动角分别为163.5°和7°,具有良好的透气性和柔软性.FESEM可明显观察到纤维表面存在一层微/纳多尺度复合膜.

  3. Monolithic optofluidic ring resonator lasers created by femtosecond laser nanofabrication.

    Science.gov (United States)

    Chandrahalim, Hengky; Chen, Qiushu; Said, Ali A; Dugan, Mark; Fan, Xudong

    2015-05-21

    We designed, fabricated, and characterized a monolithically integrated optofluidic ring resonator laser that is mechanically, thermally, and chemically robust. The entire device, including the ring resonator channel and sample delivery microfluidics, was created in a block of fused-silica glass using a 3-dimensional femtosecond laser writing process. The gain medium, composed of Rhodamine 6G (R6G) dissolved in quinoline, was flowed through the ring resonator. Lasing was achieved at a pump threshold of approximately 15 μJ mm(-2). Detailed analysis shows that the Q-factor of the optofluidic ring resonator is 3.3 × 10(4), which is limited by both solvent absorption and scattering loss. In particular, a Q-factor resulting from the scattering loss can be as high as 4.2 × 10(4), suggesting the feasibility of using a femtosecond laser to create high quality optical cavities.

  4. Biomimetic silica encapsultation of living cells

    Science.gov (United States)

    Jaroch, David Benjamin

    Living cells perform complex chemical processes on size and time scales that artificial systems cannot match. Cells respond dynamically to their environment, acting as biological sensors, factories, and drug delivery devices. To facilitate the use of living systems in engineered constructs, we have developed several new approaches to create stable protective microenvironments by forming bioinspired cell-membrane-specific silica-based encapsulants. These include vapor phase deposition of silica gels, use of endogenous membrane proteins and polysaccharides as a site for silica nucleation and polycondensation in a saturated environment, and protein templated ordered silica shell formation. We demonstrate silica layer formation at the surface of pluripotent stem-like cells, bacterial biofilms, and primary murine and human pancreatic islets. Materials are characterized by AFM, SEM and EDS. Viability assays confirm cell survival, and metabolite flux measurements demonstrate normal function and no major diffusion limitations. Real time PCR mRNA analysis indicates encapsulated islets express normal levels of genetic markers for β-cells and insulin production. The silica glass encapsulant produces a secondary bone like calcium phosphate mineral layer upon exposure to media. Such bioactive materials can improve device integration with surrounding tissue upon implantation. Given the favorable insulin response, bioactivity, and long-term viability observed in silica-coated islets, we are currently testing the encapsulant's ability to prevent immune system recognition of foreign transplants for the treatment of diabetes. Such hybrid silica-cellular constructs have a wide range of industrial, environmental, and medical applications.

  5. Monolithic molecularly imprinted polymeric capillary columns for isolation of aflatoxins.

    Science.gov (United States)

    Szumski, Michał; Grzywiński, Damian; Prus, Wojciech; Buszewski, Bogusław

    2014-10-17

    Monolithic molecularly imprinted polymers extraction columns have been prepared in fused-silica capillaries by UV or thermal polymerization in a two-step process. First, a poly-(trimethylolpropane trimethacrylate) (polyTRIM) core monolith was synthesized either by UV or thermal polymerization. Then it was grafted with the mixture of methacrylic acid (MAA) as a functional monomer, ethylene dimethacrylate (EDMA) as a cross-linking agent, 5,7-dimethoxycoumarin (DMC) as an aflatoxin-mimicking template, toluene as a porogen solvent and 2,2-azobis-(2-methylpropionitrile) (AIBN) as an initiator of the polymerization reaction. Different thermal condition of the photografting and different concentrations of the grafting mixture were tested during polymerization. The extraction capillary columns were evaluated in the terms of their hydrodynamic and chromatographic properties. Retention coefficients for aflatoxin B1 and DMC were used for assessment of the selectivity and imprinting factor. The obtained results indicate that the temperature of photografting and concentration of the grafting mixture are key parameters that determine the quality of the prepared MIPs. From the MIP columns characterized by the highest permeability the column of the highest imprinting factor was applied for isolation of aflatoxins B1, B2, G1 and G2 from the model aqueous sample followed by on-line chromatographic separation. The process was performed using a micro-MISPE-microLC-LIF system of a novel design, which allowed for detection of the eluates from the sample preparation part as well as from the chromatographic separation.

  6. 介孔分子筛/线性酚醛树脂杂化材料的制备及表征%Preparation and Characterization of Mesoporous Silica/ Novolac Type Phenol-Formaldehyde Resin Hybrid Materials

    Institute of Scientific and Technical Information of China (English)

    余传柏; 韦春; 刘红霞; 蒙礼统

    2012-01-01

    Mesoporous silica/novolac type phenol-formaldehyde resin hybrid materials were prepared via in situ polymerization at the silica SBA-15,which was treated with γ-glycidyl oxypropyl trimethoxysilane(KH560) as coupling agent.SBA-15,SBA-15-KH560 and E-SBA-15/PF were characterized and analyzed with X-ray diffraction(XRD),N2 adsorption isotherm,Fourier transform infrared spectroscopic(FT-IR) and thermogravimetric analysis(TGA) respectively.The results indicate that KH560 was chemically grafted onto SBA-15,and PF distributed into the inner and outer path of the SBA-15.An interpenetrating network of organic-inorganic was formed in this hybrid materials.The regular structure of SBA-15 was little influenced with KH560,but it was greatly modified viain situ polymertization.%利用水热法合成介孔分子筛(SBA-15),选择KH560对其表面进行修饰后采用原位聚合的方法制备了介孔分子筛/线性酚醛树脂(SBA-15/PF)有机无机杂化材料。通过傅立叶红外光谱(FT-IR)、X射线衍射(XRD)、N2吸附和热失重分析(TGA)等表征手段对杂化材料的制备过程进行跟踪研究。结果表明,KH-560已嫁接到SBA-15的内外表面,线性酚醛树脂分布于介孔分子筛孔道内外,并与SBA-15存在键接作用,形成有机无机互穿网络结构;表面修饰过程对SBA-15有序结构影响较小,而原位聚合会破坏介孔分子筛部分有序结构。

  7. All-optical SR flip-flop based on SOA-MZI switches monolithically integrated on a generic InP platform

    Science.gov (United States)

    Pitris, St.; Vagionas, Ch.; Kanellos, G. T.; Kisacik, R.; Tekin, T.; Broeke, R.; Pleros, N.

    2016-03-01

    At the dawning of the exaflop era, High Performance Computers are foreseen to exploit integrated all-optical elements, to overcome the speed limitations imposed by electronic counterparts. Drawing from the well-known Memory Wall limitation, imposing a performance gap between processor and memory speeds, research has focused on developing ultra-fast latching devices and all-optical memory elements capable of delivering buffering and switching functionalities at unprecedented bit-rates. Following the master-slave configuration of electronic Flip-Flops, coupled SOA-MZI based switches have been theoretically investigated to exceed 40 Gb/s operation, provided a short coupling waveguide. However, this flip-flop architecture has been only hybridly integrated with silica-on-silicon integration technology exhibiting a total footprint of 45x12 mm2 and intra-Flip-Flop coupling waveguide of 2.5cm, limited at 5 Gb/s operation. Monolithic integration offers the possibility to fabricate multiple active and passive photonic components on a single chip at a close proximity towards, bearing promises for fast all-optical memories. Here, we present for the first time a monolithically integrated all-optical SR Flip-Flop with coupled master-slave SOA-MZI switches. The photonic chip is integrated on a 6x2 mm2 die as a part of a multi-project wafer run using library based components of a generic InP platform, fiber-pigtailed and fully packaged on a temperature controlled ceramic submount module with electrical contacts. The intra Flip-Flop coupling waveguide is 5 mm long, reducing the total footprint by two orders of magnitude. Successful flip flop functionality is evaluated at 10 Gb/s with clear open eye diagram, achieving error free operation with a power penalty of 4dB.

  8. Monolithically integrated absolute frequency comb laser system

    Energy Technology Data Exchange (ETDEWEB)

    Wanke, Michael C.

    2016-07-12

    Rather than down-convert optical frequencies, a QCL laser system directly generates a THz frequency comb in a compact monolithically integrated chip that can be locked to an absolute frequency without the need of a frequency-comb synthesizer. The monolithic, absolute frequency comb can provide a THz frequency reference and tool for high-resolution broad band spectroscopy.

  9. Nanosecond monolithic CMOS readout cell

    Science.gov (United States)

    Souchkov, Vitali V.

    2004-08-24

    A pulse shaper is implemented in monolithic CMOS with a delay unit formed of a unity gain buffer. The shaper is formed of a difference amplifier having one input connected directly to an input signal and a second input connected to a delayed input signal through the buffer. An elementary cell is based on the pulse shaper and a timing circuit which gates the output of an integrator connected to the pulse shaper output. A detector readout system is formed of a plurality of elementary cells, each connected to a pixel of a pixel array, or to a microstrip of a plurality of microstrips, or to a detector segment.

  10. Compact monolithic capacitive discharge unit

    Science.gov (United States)

    Roesler, Alexander W.; Vernon, George E.; Hoke, Darren A.; De Marquis, Virginia K.; Harris, Steven M.

    2007-06-26

    A compact monolithic capacitive discharge unit (CDU) is disclosed in which a thyristor switch and a flyback charging circuit are both sandwiched about a ceramic energy storage capacitor. The result is a compact rugged assembly which provides a low-inductance current discharge path. The flyback charging circuit preferably includes a low-temperature co-fired ceramic transformer. The CDU can further include one or more ceramic substrates for enclosing the thyristor switch and for holding various passive components used in the flyback charging circuit. A load such as a detonator can also be attached directly to the CDU.

  11. Hybrid response surface methodology-genetic algorithm optimization of ultrasound-assisted transesterification of waste oil catalysed by immobilized lipase on mesoporous silica/iron oxide magnetic core-shell nanoparticles.

    Science.gov (United States)

    Karimi, Mahmoud; Keyhani, Alireza; Akram, Asadolah; Rahman, Masoud; Jenkins, Bryan; Stroeve, Pieter

    2013-01-01

    The production ofbiodiesel by transesterification of waste cooking oil (WCO) to partially substitute petroleum diesel is one of the measures for solving the twin problems of environment pollution and energy demand. An environmentally benign process for the enzymatic transesterification using immobilized lipase has attracted considerable attention for biodiesel production. Here, a superparamagnetic, high surface area substrate for lipase immobilization is evaluated. These immobilization substrates are composed of mesoporous silica/superparamagnetic iron oxide core-shell nanoparticles. The effects of methanol ratio to WCO, lipase concentration, water content and reaction time on the synthesis of biodiesel were analysed by utilizing the response surface methodology (RSM). A quadratic response surface equation for calculating fatty acid methyl ester (FAME) content as the objective function was established based on experimental data obtained in accordance with the central composite design. The RSM-based model was then used as the fitness function for genetic algorithm (GA) to optimize its input space. Hybrid RSM-GA predicted the maximum FAME content (91%) at the optimum level of medium variables: methanol ratio to WCO, 4.34; lipase content, 43.6%; water content, 10.22%; and reaction time, 6h. Moreover, the immobilized lipase could be used for four times without considerable loss of the activity.

  12. Preparation of a thermoresponsive polymer grafted polystyrene monolithic capillary for the separation of bioactive compounds.

    Science.gov (United States)

    Koriyama, Takuya; Asoh, Taka-Aki; Kikuchi, Akihiko

    2016-11-01

    To develop aqueous microseparation columns for bioactive compounds, a thermoresponsive polymer grafted polymer monolith was prepared inside silica capillaries having an I.D. of 100μm by polymerization of styrene (St) with m/p-divinylbenzene (DVB) in the presence of polydimethylsiloxane as porogen, followed by surface-initiated atom transfer radical polymerization (SI-ATRP) of N-isopropylacrylamide (NIPAAm). SEM analysis indicated that the resulting poly(N-isopropylacrylamide) (PNIPAAm) grafted polystyrene monolith had a consecutive three-dimensionally interconnected structure and through-pores, similar to the base polystyrene (PSt) monolith. The elution behavior of steroids with different hydrophobicity was evaluated using micro-high-performance liquid chromatography in sole aqueous mobile phase. Temperature dependent interaction changes were observed between steroids and the PNIPAAm modified surfaces. Furthermore, the interaction between bioactive compounds and the PNIPAAm grafted PSt surfaces was controlled and eventually separate these molecules with different hydrophobicities by simple temperature modulation in aqueous environment. The PNIPAAm grafted PSt monolithic capillary showed improved separation properties of bioactive compounds, compared with a PNIPAAm grafted hollow capillary in aqueous environment.

  13. Hybrid silica nanoparticles for sequestration and luminescence detection of trivalent rare-earth ions (Dy{sup 3+} and Nd{sup 3+}) in solution

    Energy Technology Data Exchange (ETDEWEB)

    Topel, Seda Demirel; Legaria, Elizabeth Polido [Swedish University of Agricultural Sciences (SLU), Department of Chemistry (Sweden); Tiseanu, Carmen [National Institute for Laser, Plasma and Radiation Physics (Romania); Rocha, João [University of Aveiro, Department of Chemistry CICECO (Portugal); Nedelec, Jean-Marie [Clermont Université, ENSCCF, Institute de Chimie de Clermont-Ferrand (France); Kessler, Vadim G.; Seisenbaeva, Gulaim A., E-mail: gulaim.seisenbaeva@slu.se [Swedish University of Agricultural Sciences (SLU), Department of Chemistry (Sweden)

    2014-12-15

    New hybrid material-based adsorbents acting also as luminescent probes upon uptake of trivalent rare-earth (RE) ions Nd{sup 3+} and Dy{sup 3+} have been developed. SiO{sub 2} NPs functionalized by three different organic ligands, N-aminopropylen-amido-iminodiacetic acid (L1), pyridine-α,β-dicarboxylic acid bis(propylenamide) (L2), and N-propylen-iminodiacetic acid (L3), have been produced and fully characterized by {sup 13}C, {sup 1}H, and {sup 29}Si solid-state NMR, FTIR, TGA, XRD, TEM, nitrogen gas adsorption, and also by NTA and DLS in solution. The synthesized hybrid materials are well dispersible and stable in aqueous solutions according to NTA and consist of spheres with diameters less than 100 nm. Their affinities to the lanthanide ions Dy{sup 3+} and Nd{sup 3+} have been investigated in aqueous solution and characterized by SEM–EDS and complexometric titration, demonstrating that they can be successfully used as adsorbents for sequestration of trivalent RE ions. The adsorbed RE ions can efficiently be desorbed from saturated nanoadsorbents by addition of hydrochloric acid. The produced nanomaterials may also be used as luminescent probes for Dy{sup 3+} and Nd{sup 3+} ions in solution.

  14. A new anion-exchange/hydrophobic monolith as stationary phase for nano liquid chromatography of small organic molecules and inorganic anions.

    Science.gov (United States)

    Aydoğan, Cemil

    2015-05-01

    In this study, an anion-exchange/hydrophobic polymethacrylate-based stationary phase was prepared for nano-liquid chromatography of small organic molecules and inorganic anions. The stationary phase was synthesized by in situ polymerization of 3-chloro-2-hydroxypropylmethacrylate and ethylene dimethacrylate inside silanized 100 μm i.d. fused silica capillary. The porogen mixture consisted of toluene and dodecanol. The pore size distrubution profiles of the resulting monolith were determined by mercury intrusion porosimetry and the morphology of the prepared monolith was investigated by scanning electron microscope. Good permeability, stability and column efficiency were observed on the monolithic column with nano flow. The produced monolithic column, which contains reactive chloro groups, was then modified by reaction with N,N-dimethyl-N-dodecylamine to obtain an anion-exchange/hydrophobic monolithic stationary phase. The functionalized monolith contained ionizable amine groups and hydrophobic groups that are useful of anion-exchange/hydrophobic mixed-mode chromatography. The final monolithic column performance with respect to anion-exchange and hydrophobic interactions was assesed by the separation of alkylbenzene derivatives, phenolic compounds and inorganic anions, respectively. Theoretical plate numbers up to 23,000 plates/m were successfully achieved in the separation of inorganic anions.

  15. Chromatographic selectivity of poly(alkyl methacrylate-co-divinylbenzene) monolithic columns for polar aromatic compounds by pressure-driven capillary liquid chromatography.

    Science.gov (United States)

    Lin, Shu-Ling; Wang, Chih-Chieh; Fuh, Ming-Ren

    2016-10-05

    In this study, divinylbenzene (DVB) was used as the cross-linker to prepare alkyl methacrylate (AlMA) monoliths for incorporating π-π interactions between the aromatic analytes and AlMA-DVB monolithic stationary phases in capillary LC analysis. Various AlMA/DVB ratios were investigated to prepare a series of 30% AlMA-DVB monolithic stationary phases in fused-silica capillaries (250-μm i.d.). The physical properties (such as porosity, permeability, and column efficiency) of the synthesized AlMA-DVB monolithic columns were investigated for characterization. Isocratic elution of phenol derivatives was first employed to evaluate the suitability of the prepared AlMA-DVB columns for small molecule separation. The run-to-run (0.16-1.20%, RSD; n = 3) and column-to-column (0.26-2.95%, RSD; n = 3) repeatabilities on retention times were also examined using the selected AlMA-DVB monolithic columns. The π-π interactions between the aromatic ring and the DVB-based stationary phase offered better recognition on polar analytes with aromatic moieties, which resulted in better separation resolution of aromatic analytes on the AlMA-DVB monolithic columns. In order to demonstrate the capability of potential environmental and/or food safety applications, eight phenylurea herbicides with single benzene ring and seven sulfonamide antibiotics with polyaromatic moieties were analyzed using the selected AlMA-DVB monolithic columns.

  16. P(EA-MAn-APTES)/二氧化硅有机无机杂化材料的合成和表征%Synthesis and characterization of hybrid organic-inorganic materials based on EA-Man-APTES and silica

    Institute of Scientific and Technical Information of China (English)

    邱凤仙; 周钰明; 刘举正; 张旭苹

    2005-01-01

    采用γ氨丙基三乙氧基硅烷 (APTES)作为偶联剂,以丙烯酸乙酯(EA)、顺丁烯二酸酐(MAn)和正硅酸乙酯(TEOS)为原料,通过自由基溶液聚合和溶胶凝胶过程制得了P(EA-MAn-APTES)/二氧化硅有机无机杂化材料,其中TEOS的质量分数从0变化至25%.利用傅立叶红外(FT-IR)光谱、溶胶抽取、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、示差扫描量热法(DSC)和热重分析(TGA)性能测试装置对材料的结构、凝胶含量、表面形貌、粒子大小和热性能进行了表征.结果表明:有机相与无机相之间是以共价键结合的,杂化材料中凝胶的含量较高,聚合物基体中SiO2是纳米复合的,具有较好的分散性和热稳定性.%Poly (EA-Man-APTES)/silica hybrid materials were successfully prepared from Ethyl acrylate (EA),maleic anhydride (Man) and tetraethoxysilane (TEOS) in the presence of a coupling agent 3-aminopropyltriethoxysilane (APTES),by free-radical solution polymerization and in situ sol-gel process.The mass fraction of TEOS varied from 0 to 25%.The hybrid materials were characterized by the methods of FT-IR spectra,solvent extraction,scanning electron microscope (SEM),transmission electron microscope (TEM),differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) measuring apparatus to get their structures,gel contents,morphologies,particle sizes and thermal performances.The results show that the covalent bonds are between organic and inorganic phases,gel contents in the hybrid materials are much higher,the SiO2 phase is well dispersed in the polymer matrix,silicon dioxide exist at nanoscale in the composites and have excellent thermal stability.

  17. Tuning of the excitation wavelength in Eu(3+)-aminophenyl based polyfluorinated β-diketonate complexes: a red-emitting Eu(3+)-complex encapsulated in a silica/polymer hybrid material excited by blue light.

    Science.gov (United States)

    Usha Gangan, T V; Reddy, M L P

    2015-09-28

    We describe herein the synthesis, characterization and photophysical properties of a series of europium complexes based on three aminophenyl based polyfluorinated β-diketonates, namely, 1-(4-aminophenyl)-4,4,5,5,5-pentafluoro-3-hydroxypent-2-en-1-one, 1-(4-(dimethylamino)phenyl)-4,4,5,5,5-pentafluoro-3-hydroxypent-2-en-1-one and 1-(4-(diphenylamino)phenyl)-4,4,5,5,5-pentafluoro-3-hydroxypent-2-en-1-one, and an ancillary ligand, 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene oxide. The results demonstrated that the triphenylamine based polyfluorinated Eu(3+)-β-diketonate complexes dramatically red-shifted the excitation maximum to the visible region (λex, max = 400 nm) with an impressive quantum yield (40%) as compared to the simple Eu(3+)-aminophenyl-β-diketonate complexes (λex, max = 370 nm). This can be explained on the basis of the conjugation between nitrogen lone pair electrons and the phenyl π-electrons in the β-diketonate ligand system. On the other hand, the electron-donating dimethylamino group (Hammett constant: σp = -0.83) containing Eu(3+)-β-diketonate complexes moderately shifted the excitation maximum in the UV region from 370 to 380 nm as compared to unsubstituted aminophenyl (Hammett constant: σp = -0.66) Eu(3+) complexes. The displacement of water molecules in aminophenyl based Eu(3+)-β-diketonate binary complexes by a rigid phosphine oxide ligand richly enhances the photoluminescence quantum yields as well as the excited state lifetime values of the corresponding ternary complexes. As an integral part of this work, hybrid materials have been developed through a sol-gel route by encapsulating a ternary Eu(3+) compound in a silica/polymer hybrid for high performance luminescence applications. In addition, a bright red-emitting diode was fabricated by coating the designed hybrid material onto a 400 nm emitting InGaN chip and the photoluminescence was examined. Notably, the current study clearly shows that the developed triphenylamine

  18. Hybrid Antifouling and Antimicrobial Coatings Prepared by Electroless Co-Deposition of Fluoropolymer and Cationic Silica Nanoparticles on Stainless Steel: Efficacy against Listeria monocytogenes.

    Science.gov (United States)

    Huang, Kang; Chen, Juhong; Nugen, Sam R; Goddard, Julie M

    2016-06-29

    Controlling formation, establishment, and proliferation of microbial biofilms on surfaces is critical for ensuring public safety. Herein, we report on the synthesis of antimicrobial nanoparticles and their co-deposition along with fluorinated nanoparticles during electroless nickel plating of stainless steel. Plating bath composition is optimized to ensure sufficiently low surface energy to resist fouling and microbial adhesion as well as to exert significant (>99.99% reduction) antimicrobial activity against Listeria monocytogenes. The resulting coatings present hybrid antifouling and antimicrobial character, can be applied onto stainless steel, and do not rely on leaching or migration of the antimicrobial nanoparticles to be effective. Such coatings can support reducing public health issues related to microbial cross-contamination in areas such as food processing, hospitals, and water purification.

  19. Application of high silica zeolite ZSM-5 in a hybrid treatment process based on sequential adsorption and ozonation for VOCs elimination.

    Science.gov (United States)

    Zaitan, Hicham; Manero, Marie Hélène; Valdés, Héctor

    2016-03-01

    In this study, a hydrophobic synthetic zeolite, namely ZSM-5 is chosen as an adsorbent/catalyst for toluene removal. Experimental results showed that toluene adsorption onto ZSM-5 was favourable, following a Langmuir adsorption isotherm model. ZSM-5 zeolite was regenerated using gaseous ozone at low temperature. Adsorbed toluene was oxidised, releasing mainly CO2 and H2O. Traces of oxidation by-products such as acetic acid and acetaldehyde were formed and remained adsorbed after the oxidativate regeneration with ozone. After four successive cycles of adsorption/ozonation, the adsorption efficiency was not affected (92%-99%). These results showed that volatile organic compound (VOC) removal by adsorption onto ZSM-5 zeolite followed by ozone regeneration could be used as a promising hybrid process for the control of VOC emissions in terms of efficiency.

  20. Microfluidic devices and methods including porous polymer monoliths

    Science.gov (United States)

    Hatch, Anson V; Sommer, Gregory J; Singh, Anup K; Wang, Ying-Chih; Abhyankar, Vinay V

    2014-04-22

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  1. Properties of Natural Rubber Composites with Kaolin and Silica Hybrid Filler%高岭土/白炭黑并用填充天然橡胶复合材料的性能

    Institute of Scientific and Technical Information of China (English)

    张玉德; 刘钦甫; 李和平; 陆银平; 张乾

    2011-01-01

    A series of natural rubber (NR) composites with modified kaolin(MK)and precipitated silica(PS)were prepared by melt blending,and their microstruture,gas barrier properties and mechanical properties were characterized The results show that flake-like kaolinite and spherical silica particles are evenly dispersed in the natural rubber matrix.When NR is filled by MK or PS separately,the gas barrier properties of NR composites are improved gradually with the increasing of MK content,and MK is superior to PS in the barrier and reinforcing capability.When NR is filled by MK and PS blends,their gas barrier properties,tensile strength and tensile modulus all surpass that of NR composites filled by MK or PS separately,and MK/PS hybrid filler further improves the gas barrier properties and mechanical properties of NR composites.%以高岭土和白炭黑作为增强剂,采用熔融共混法制备了一系列的天然橡胶(NR)复合材料,并对其微观结构、气体阻隔性能和力学性能进行了表征.结果表明,改性高岭土(MK)以片层结构,白炭黑(PS)以球状结构,均匀分散于NR基体之中;MK与PS单独填充NR时,随着MK填充量的增加,NR复合材料的气体阻隔性能逐渐提高,而且MK的增强和阻隔作用都优于PS;MK与PS并用填充时,混合物填充NR复合材料的阻隔性能、拉伸模量和拉伸强度都优于MK、PS单独填充的NR复合材料,填料并用更有效地改善了NR复合材料的气体阻隔性能和力学性能.

  2. Spectroscopic studies of Cu2+ ions in sol–gel derived silica matrix

    Indian Academy of Sciences (India)

    P I Paulose; Gin Jose; Vinoy Thomas; Gijo Jose; N V Unnikrishnan; M K R Warrier

    2002-02-01

    The Cu2+ ion doped silica gel matrices in monolithic shape were prepared by hydrolysis and condensation of tetraethyl orthosilicate (TEOS). The absorption, transmittance and fluorescence spectra of the gel matrices heat treated at different temperatures were monitored. The loss of water and hydroxyl group from silica network changes the optical properties of the Cu2+ ions in the host, noted by the change in colour of monolith and spectral characteristics. The pronounced blue shift observed (700–900 nm to 600–850 nm) for the broad band of the absorption spectra of the samples heated up to 700°C is attributed to the ligand field splitting and partial removal of hydroxyl group from the silica matrices. The results indicate broadband filtering effects of the samples in the wavelength region 400–600 nm. Absorption and fluorescence spectra of the glass matrices heated to 1000°C confirms the conversion of Cu2+ ion to Cu+ ion.

  3. A Novel Approach for Entrapment of Biopolymers in Silica Matrix by Sol-gel Technique

    Institute of Scientific and Technical Information of China (English)

    Yu.Shchipunov

    2007-01-01

    1 Results The entrapment of biopolymers into silica by the sol-gel technique meets with incompatibility of inorganic and bioorganic components. The aim was to develop a compatible procedure biomimicking the biomineralization processes in the living nature. A suggested solution in Ref.[1-2] for the biopolymer entrapment into silica matrix is based on a novel silica precursor. The developed approach is distinguished from the common technique for fabrication of hybrid biopolymer-silica nanocomposite materi...

  4. Monolithic Continuous-Flow Bioreactors

    Science.gov (United States)

    Stephanopoulos, Gregory; Kornfield, Julia A.; Voecks, Gerald A.

    1993-01-01

    Monolithic ceramic matrices containing many small flow passages useful as continuous-flow bioreactors. Ceramic matrix containing passages made by extruding and firing suitable ceramic. Pores in matrix provide attachment medium for film of cells and allow free movement of solution. Material one not toxic to micro-organisms grown in reactor. In reactor, liquid nutrients flow over, and liquid reaction products flow from, cell culture immobilized in one set of channels while oxygen flows to, and gaseous reaction products flow from, culture in adjacent set of passages. Cells live on inner surfaces containing flowing nutrient and in pores of walls of passages. Ready access to nutrients and oxygen in channels. They generate continuous high yield characteristic of immobilized cells, without large expenditure of energy otherwise incurred if necessary to pump nutrient solution through dense biomass as in bioreactors of other types.

  5. Anisotropically structured magnetic aerogel monoliths

    Science.gov (United States)

    Heiligtag, Florian J.; Airaghi Leccardi, Marta J. I.; Erdem, Derya; Süess, Martin J.; Niederberger, Markus

    2014-10-01

    Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture.Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture. Electronic supplementary information (ESI) available: Digital photographs of dispersions and gels with different water-to-ethanol ratios; magnetic measurements of an anatase aerogel containing 0.25 mol% Fe3O4 nanoparticles; XRD patterns of the iron oxide and

  6. THERMALLY CLEAVABLE HYBRID MATERIALS

    Directory of Open Access Journals (Sweden)

    Constantin Gaina

    2011-12-01

    Full Text Available Thermally cleavable hybrid materials were prepared by the Diels-Alder cycloaddition reaction of poly(vinyl furfural to N phenylmaleimido-N’-(triethoxysilylpropylurea followed by the sol-gel condensation reaction of trietoxysilyl groups with water and acetic acid. Thermal and dynamic mechanical analysis, dielectric and FTIR spectroscopy were used to characterize the structure and properties of the composites. The size of the inorganic silica particles in the hybrid material varied dependent on the silica content. The DSC study of the prepared materials revealed that the cleavage process of the formed cycloadducts takes place at temperatures varying between 143-165°C and is an endothermic process.

  7. Preparation and evaluation of poly(alkyl methacrylate-co-methacrylic acid-co-ethylene dimethacrylate) monolithic columns for separating polar small molecules by capillary liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Shu-Ling; Wu, Yu-Ru; Lin, Tzuen-Yeuan; Fuh, Ming-Ren, E-mail: msfuh@scu.edu.tw

    2015-04-29

    Highlights: • Methacrylic acid (MAA) was used to increase hydrophilicity of polymeric monoliths. • Fast separation of phenol derivatives was achieved in 5 min using MAA-incorporated column. • Separations of aflatoxins and phenicol antibiotics were achieved using MAA-incorporated column. - Abstract: In this study, methacrylic acid (MAA) was incorporated with alkyl methacrylates to increase the hydrophilicity of the synthesized ethylene dimethacrylate-based (EDMA-based) monoliths for separating polar small molecules by capillary LC analysis. Different alkyl methacrylate–MAA ratios were investigated to prepare a series of 30% alkyl methacrylate–MAA–EDMA monoliths in fused-silica capillaries (250-μm i.d.). The porosity, permeability, and column efficiency of the synthesized MAA-incorporated monolithic columns were characterized. A mixture of phenol derivatives is employed to evaluate the applicability of using the prepared monolithic columns for separating small molecules. Fast separation of six phenol derivatives was achieved in 5 min with gradient elution using the selected poly(lauryl methacrylate-co-MAA-co-EDMA) monolithic column. In addition, the effect of acetonitrile content in mobile phase on retention factor and plate height as well as the plate height-flow velocity curves were also investigated to further examine the performance of the selected poly(lauryl methacrylate-co-MAA-co-EDMA) monolithic column. Moreover, the applicability of prepared polymer-based monolithic column for potential food safety applications was also demonstrated by analyzing five aflatoxins and three phenicol antibiotics using the selected poly(lauryl methacrylate-co-MAA-co-EDMA) monolithic column.

  8. Monolithic Time Delay Integrated APD Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall goal of the proposed program by Epitaxial Technologies is to develop monolithic time delay integrated avalanche photodiode (APD) arrays with sensitivity...

  9. Eu{sup 3+}-modification of luminescent hybrid bimodal mesoporous silicas with various anions (NO{sub 3}{sup −}, CH{sub 3}COO{sup −}, and Cl{sup −})

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Feng; Sun, Jihong, E-mail: jhsun@bjut.edu.cn; Wang, Jinpeng; Bai, Shiyang; Wu, Xia

    2014-06-01

    In order to enhance the intensity of luminescent hybrid bimodal mesoporous silica (LHMS), the rare earth Eu{sup 3+} ion was employed as an enhancer to modify 1,8-naphthalic anhydride (NA) molecules. The modified LHMS were prepared with various anions of europium salts including Cl{sup −}, NO{sub 3}{sup −}, and CH{sub 3}COO{sup −}. The structure and photoluminescence properties of the obtained samples were characterized by XRD, TEM, N{sub 2}-adsorption/desorption, FT-IR, TGA, ICP-OES, and PL measurements. The results showed that the bimodal mesoporous system of BMMs could be preserved after functionalization via grafted Eu{sup 3+}-modified NA molecules onto mesoporous matrix. However, the structure parameters and textural properties of resultant LHMS series were obviously influenced by the anions volume. Meanwhile, the luminescent performances of LHMS series were seriously impacted by both of the binding force between Eu{sup 3+} and various anions and steric hindrance of the anions, resulting in the intensity of emission peak of obtained LHMS series declining as following order: LHMS-EN (NO{sub 3}{sup −}) > LHMS-EA (CH{sub 3}COO{sup −}) > LHMS-EC (Cl{sup −}). Finally, the related mechanism was discussed in-depth. - Graphical abstract: Display Omitted - Highlights: • Luminescent intensity of LHMS was enhanced by europium salts. • Textural properties of LHMS were influenced by various anions. • Effects of binding force and steric hindrance on luminescent performance were remarkable.

  10. Silica in Protoplanetary Disks

    CERN Document Server

    Sargent, B A; Tayrien, C; McClure, M K; Li, A; Basu, A R; Manoj, P; Watson, D M; Bohac, C J; Furlan, E; Kim, K H; Green, J D; Sloan, G C

    2008-01-01

    Mid-infrared spectra of a few T Tauri stars (TTS) taken with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope show prominent narrow emission features indicating silica (crystalline silicon dioxide). Silica is not a major constituent of the interstellar medium; therefore, any silica present in the circumstellar protoplanetary disks of TTS must be largely the result of processing of primitive dust material in the disks surrouding these stars. We model the silica emission features in our spectra using the opacities of various polymorphs of silica and their amorphous versions computed from earth-based laboratory measurements. This modeling indicates that the two polymorphs of silica, tridymite and cristobalite, which form at successively higher temperatures and low pressures, are the dominant forms of silica in the TTS of our sample. These high temperature, low pressure polymorphs of silica present in protoplanetary disks are consistent with a grain composed mostly of tridymite named Ada found...

  11. Multifunctional mesoporous silica catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Victor Shang-Yi; Tsai, Chih-Hsiang; Chen, Hung-Ting; Pruski, Marek; Kobayashi, Takeshi

    2015-03-31

    The present invention provides bifunctional silica mesoporous materials, including mesoporous silica nanoparticles ("MSN"), having pores modified with diarylammonium triflate and perfluoroaryl moieties, that are useful for the acid-catalyzed esterification of organic acids with organic alcohols.

  12. Activated Carbon Fiber Monoliths as Supercapacitor Electrodes

    Directory of Open Access Journals (Sweden)

    Gelines Moreno-Fernandez

    2017-01-01

    Full Text Available Activated carbon fibers (ACF are interesting candidates for electrodes in electrochemical energy storage devices; however, one major drawback for practical application is their low density. In the present work, monoliths were synthesized from two different ACFs, reaching 3 times higher densities than the original ACFs’ apparent densities. The porosity of the monoliths was only slightly decreased with respect to the pristine ACFs, the employed PVDC binder developing additional porosity upon carbonization. The ACF monoliths are essentially microporous and reach BET surface areas of up to 1838 m2 g−1. SEM analysis reveals that the ACFs are well embedded into the monolith structure and that their length was significantly reduced due to the monolith preparation process. The carbonized monoliths were studied as supercapacitor electrodes in two- and three-electrode cells having 2 M H2SO4 as electrolyte. Maximum capacitances of around 200 F g−1 were reached. The results confirm that the capacitance of the bisulfate anions essentially originates from the double layer, while hydronium cations contribute with a mixture of both, double layer capacitance and pseudocapacitance.

  13. Silica extraction from geothermal water

    Science.gov (United States)

    Bourcier, William L; Bruton, Carol J

    2014-09-23

    A method of producing silica from geothermal fluid containing low concentration of the silica of less than 275 ppm includes the steps of treating the geothermal fluid containing the silica by reverse osmosis treatment thereby producing a concentrated fluid containing the silica, seasoning the concentrated fluid thereby producing a slurry having precipitated colloids containing the silica, and separating the silica from the slurry.

  14. Microporous Silica Based Membranes for Desalination

    Directory of Open Access Journals (Sweden)

    João C. Diniz da Costa

    2012-09-01

    Full Text Available This review provides a global overview of microporous silica based membranes for desalination via pervaporation with a focus on membrane synthesis and processing, transport mechanisms and current state of the art membrane performance. Most importantly, the recent development and novel concepts for improving the hydro-stability and separating performance of silica membranes for desalination are critically examined. Research into silica based membranes for desalination has focussed on three primary methods for improving the hydro-stability. These include incorporating carbon templates into the microporous silica both as surfactants and hybrid organic-inorganic structures and incorporation of metal oxide nanoparticles into the silica matrix. The literature examined identified that only metal oxide silica membranes have demonstrated high salt rejections under a variety of feed concentrations, reasonable fluxes and unaltered performance over long-term operation. As this is an embryonic field of research several target areas for researchers were discussed including further improvement of the membrane materials, but also regarding the necessity of integrating waste or solar heat sources into the final process design to ensure cost competitiveness with conventional reverse osmosis processes.

  15. Monolithically integrated Ge CMOS laser

    Science.gov (United States)

    Camacho-Aguilera, Rodolfo

    2014-02-01

    Ge-on-Si devices are explored for photonic integration. Through the development of better growth techniques, monolithic integration, laser design and prototypes, it was possible to probe Ge light emitters with emphasis on lasers. Preliminary worked shows thermal photonic behavior capable of enhancing lamination at high temperatures. Increase luminescence is observed up to 120°C from L-band contribution. Higher temperatures show contribution from Δ -band. The increase carrier thermal contribution suggests high temperature applications for Ge light emitters. A Ge electrically pumped laser was probed under 0.2% biaxial strain and doping concentration ~4.5×1019cm-3 n-type. Ge pnn lasers exhibit a gain >1000cm-1 with 8mW power output, presenting a spectrum range of over 200nm, making Ge the ideal candidate for Si photonics. Large temperatures fluctuations and process limit the present device. Theoretically a gain of >4000cm- gain is possible with a threshold of as low as 1kA/cm2. Improvements in Ge work

  16. Effect of Polishing Systems on Surface Roughness and Topography of Monolithic Zirconia.

    Science.gov (United States)

    Goo, C L; Yap, Auj; Tan, Kbc; Fawzy, A S

    2016-01-01

    This study evaluated the effect of different chairside polishing systems on the surface roughness and topography of monolithic zirconia. Thirty-five monolithic zirconia specimens (Lava PLUS, 3M ESPE) were fabricated and divided into five groups of seven and polished with the following: Group 1 (WZ)-Dura white stone followed by Shofu zirconia polishing kit; Group 2 (SZ)-Shofu zirconia polishing kit; Group 3 (CE)-Ceramiste porcelain polishers; Group 4 (CM)-Ceramaster porcelain polishers; and Group 5 (KZ)-Komet ZR zirconia polishers. All specimens were ground with a fine-grit diamond bur prior to polishing procedures to simulate clinical finishing. Baseline and post-polishing profilometric readings were recorded and delta Ra values (difference in mean surface roughness before and after polishing) were computed and analyzed using one-way analysis of variance and Scheffe post hoc test (ppolished specimens were acquired. Delta Ra values ranged from 0.146 for CE to 0.400 for KZ. Delta Ra values for KZ, WZ, and SZ were significantly greater than for CE. Significant differences in delta Ra values were also observed between KZ and CM. The SEM images obtained were consistent with the profilometric findings. Diamond-impregnated polishing systems were more effective than silica carbide-impregnated ones in reducing the surface roughness of ground monolithic zirconia.

  17. Acidic Montmorillonite/Cordierite Monolithic Catalysts for Cleavage of Cumene Hydroperoxide

    Institute of Scientific and Technical Information of China (English)

    Li Han; Yanjun Wang; Jie Zhang; Zhigang Lei; Chongpin Huang; Biaohua Chen

    2014-01-01

    In this work, a series of acidic montmorillonite/cordierite monolithic catalysts were prepared by a coating method using silica sol as the binder. The morphology and structure of the acidic montmoril onite/cordierite samples were characterized by means of X-ray diffraction (XRD), N2 adsorption/desorption isotherms, and scanning electron microscope (SEM). The cleavage of cumene hydroperoxide (CHP) in a conventional fixed-bed reactor was chosen as a model reaction to evaluate the catalytic activity of the monolithic catalysts. The influences of acidic montmorillonite loading, reaction temperature, CHP concentration, and weight hourly space velocity (WHSV) on the catalytic activity and selectivity of phenol were studied. The results indicated that the obtained acidic montmorillonite/cordierite monolithic catalysts were firm and compact, and the loading of acidic montmorillonite was found to reach 40%(by mass) after three coating operations. The surface area of acidic montmorillonite/cordierite catalysts increases greatly as acidic montmorillonite loading increases due to higher surface area of acidic montmorillonite. Under the optimal reaction conditions (acidic montmorillonite loading of 32.5%(by mass), temperature of 80 °C, a mass ratio of CHP to acetone of 1:3, and WHSV of CHP of 90 h-1), the conversion of CHP can reach 100%, and the selectivity of phenol is up to 99.8%.

  18. ROMP-Derived cyclooctene-based monolithic polymeric materials reinforced with inorganic nanoparticles for applications in tissue engineering

    Directory of Open Access Journals (Sweden)

    Franziska Weichelt

    2010-12-01

    Full Text Available Porous monolithic inorganic/polymeric hybrid materials have been prepared via ring-opening metathesis copolymerization starting from a highly polar monomer, i.e., cis-5-cyclooctene-trans-1,2-diol and a 7-oxanorborn-2-ene-derived cross-linker in the presence of porogenic solvents and two types of inorganic nanoparticles (i.e., CaCO3 and calcium hydroxyapatite, respectively using the third-generation Grubbs initiator RuCl2(Py2(IMesH2(CHPh. The physico-chemical properties of the monolithic materials, such as pore size distribution and microhardness were studied with regard to the nanoparticle type and content. Moreover, the reinforced monoliths were tested for the possible use as scaffold materials in tissue engineering, by carrying out cell cultivation experiments with human adipose tissue-derived stromal cells.

  19. Fracture resistance of monolithic zirconia molar crowns with reduced thickness

    OpenAIRE

    Nakamura, Keisuke; Harada, A.; Inagaki, R.; Kanno, Taro; Niwano, Y; Milleding, Percy; Ørtengren, Ulf Thore

    2015-01-01

    This is the accepted manuscript version. Published version is available at Acta Odontologica Scandinavica Objectives. The purpose of the present study was to analyze the relationship between fracture load of monolithic zirconia crowns and axial/occlusal thickness, and to evaluate the fracture resistance of monolithic zirconia crowns with reduced thickness in comparison with that of monolithic lithium disilicate crowns with regular thickness. Materials and methods. Monolithic zi...

  20. Development of a monolithic ferrite memory array

    Science.gov (United States)

    Heckler, C. H., Jr.; Bhiwandker, N. C.

    1972-01-01

    The results of the development and testing of ferrite monolithic memory arrays are presented. This development required the synthesis of ferrite materials having special magnetic and physical characteristics and the development of special processes; (1) for making flexible sheets (laminae) of the ferrite composition, (2) for embedding conductors in ferrite, and (3) bonding ferrite laminae together to form a monolithic structure. Major problems encountered in each of these areas and their solutions are discussed. Twenty-two full-size arrays were fabricated and fired during the development of these processes. The majority of these arrays were tested for their memory characteristics as well as for their physical characteristics and the results are presented. The arrays produced during this program meet the essential goals and demonstrate the feasibility of fabricating monolithic ferrite memory arrays by the processes developed.

  1. Carbon Fiber Composite Monoliths as Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Pickel, Joseph M [ORNL; Blom, Douglas Allen [ORNL; Burchell, Timothy D [ORNL

    2006-01-01

    Carbon fiber composite monoliths are rigid bodies that can be activated to a large surface area, have tunable porosity, and proven performance in gas separation and storage. They are ideal as catalyst supports in applications where a rigid support, with open structure and easy fluid access is desired. We developed a procedure for depositing a dispersed nanoparticulate phase of molybdenum carbide (Mo2C) on carbon composite monoliths in the concentration range of 3 to 15 wt% Mo. The composition and morphology of this phase was characterized using X-ray diffraction and electron microscopy, and a mechanism was suggested for its formation. Molybdenum carbide is known for its catalytic properties that resemble those of platinum group metals, but at a lower cost. The materials obtained are expected to demonstrate catalytic activity in a series of hydrocarbon reactions involving hydrogen transfer. This project demonstrates the potential of carbon fiber composite monoliths as catalyst supports.

  2. Carbon Fiber Composite Monoliths for Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Pickel, Joseph M [ORNL; Blom, Douglas Allen [ORNL; Burchell, Timothy D [ORNL

    2006-01-01

    Carbon fiber composite monoliths are rigid bodies that can be activated to a large surface area, have tunable porosity, and proven performance in gas separation and storage. They are ideal as catalyst supports in applications where a rigid support, with open structure and easy fluid access is desired. We developed a procedure for depositing a dispersed nanoparticulate phase of molybdenum carbide (Mo2C) on carbon composite monoliths in the concentration range of 3 to 15 wt% Mo. The composition and morphology of this phase was characterized using X-ray diffraction and electron microscopy, and a mechanism was suggested for its formation. Molybdenum carbide is known for its catalytic properties that resemble those of platinum group metals, but at a lower cost. The materials obtained are expected to demonstrate catalytic activity in a series of hydrocarbon reactions involving hydrogen transfer. This project demonstrates the potential of carbon fiber composite monoliths as catalyst supports.

  3. Eigenpolarization theory of monolithic nonplanar ring oscillators

    Science.gov (United States)

    Nilsson, Alan C.; Gustafson, Eric K.; Byer, Robert L.

    1989-01-01

    Diode-laser-pumped monolithic nonplanar ring oscillators (NPROs) in an applied magnetic field can operate as unidirectional traveling-wave lasers. The diode laser pumping, monolithic construction, and unidirectional oscillation lead to narrow linewidth radiation. Here, a comprehensive theory of the eigenpolarizations of a monolithic NPRO is presented. It is shown how the properties of the integral optical diode that forces unidirectional operation depend on the choice of the gain medium, the applied magnetic field, the output coupler, and the geometry of the nonplanar ring light path. Using optical equivalence theorems to gain insight into the polarization characteristics of the NPRO, a strategy for designing NPROs with low thresholds and large loss nonreciprocities is given. An analysis of the eigenpolarizations for one such NPRO is presented, alternative optimization approaches are considered, and the prospects for further reducing the linewidths of these lasers are briefly discussed.

  4. Monolithic cells for solar fuels

    OpenAIRE

    Rongé, Jan; Bosserez, Tom; Martel, David; Nervi, Carlo; Boarino, Luca; TAULELLE, Francis; Decher, Gero; Bordiga, Silvia; Martens, Johan

    2014-01-01

    Hybrid energy generation models based on a variety of alternative energy supply technologies are considered the best way to cope with the depletion of fossil energy resources and to limit global warming. One of the currently missing technologies is the mimic of natural photosynthesis to convert carbon dioxide and water into chemical fuel using sunlight. This idea has been around for decades, but artificial photosynthesis of organic molecules is still far away from providing real-world solutio...

  5. Physical and chemical sensing using monolithic semiconductor optical transducers

    Science.gov (United States)

    Zappe, Hans P.; Hofstetter, Daniel; Maisenhoelder, Bernd; Moser, Michael; Riel, Peter; Kunz, Rino E.

    1997-09-01

    We present two monolithically integrated optical sensor systems based on semiconductor photonic integrated circuits. These compact, robust and highly functional transducers perform all necessary optical and electro-optical functions on-chip; extension to multi-sensor arrays is easily envisaged. A monolithic Michelson interferometer for high-resolution displacement measurement and a monolithic Mach-Zehnder interferometer for refractometry are discussed.

  6. Optical and radiographical characterization of silica aerogel for Cherenkov radiator

    CERN Document Server

    Tabata, Makoto; Hatakeyama, Yoshikiyo; Kawai, Hideyuki; Morita, Takeshi; Nishikawa, Keiko

    2012-01-01

    We present optical and X-ray radiographical characterization of silica aerogels with refractive index from 1.05 to 1.07 for a Cherenkov radiator. A novel pin-drying method enables us to produce highly transparent hydrophobic aerogels with high refractive index by shrinking wet-gels. In order to investigate the uniformity in the density (i.e., refractive index) of an individual aerogel monolith, we use the laser Fraunhofer method, an X-ray absorption technique, and Cherenkov imaging by a ring imaging Cherenkov detector in a beam test. We observed an increase in density at the edge of the aerogel tiles, produced by pin-drying.

  7. Characterization of CIM monoliths as enzyme reactors.

    Science.gov (United States)

    Vodopivec, Martina; Podgornik, Ales; Berovic, Marin; Strancar, Ales

    2003-09-25

    The immobilization of the enzymes citrate lyase, malate dehydrogenase, isocitrate dehydrogenase and lactate dehydrogenase to CIM monolithic supports was performed. The long-term stability, reproducibility, and linear response range of the immobilized enzyme reactors were investigated along with the determination of the kinetic behavior of the enzymes immobilized on the CIM monoliths. The Michaelis-Menten constant K(m) and the turnover number k(3) of the immobilized enzymes were found to be flow-unaffected. Furthermore, the K(m) values of the soluble and immobilized enzyme were found to be comparable. Both facts indicate the absence of a diffusional limitation in immobilized CIM enzyme reactors.

  8. Monolithically integrated optoelectronic down-converter (MIOD)

    Science.gov (United States)

    Portnoi, Efrim L.; Venus, G. B.; Khazan, A. A.; Gorfinkel, Vera B.; Kompa, Guenter; Avrutin, Evgenii A.; Thayne, Iain G.; Barrow, David A.; Marsh, John H.

    1995-06-01

    Optoelectronic down-conversion of very high-frequency amplitude-modulated signals using a semiconductor laser simultaneously as a local oscillator and a mixer is proposed. Three possible constructions of a monolithically integrated down-converter are considered theoretically: a four-terminal semiconductor laser with dual pumping current/modal gain control, and both a passively mode-locked and a passively Q-switched semiconductor laser monolithically integrated with an electroabsorption or pumping current modulator. Experimental verification of the feasibility of the concept of down conversion in a laser diode is presented.

  9. Rapid "one-pot" preparation of polymeric monolith via photo-initiated thiol-acrylate polymerization for capillary liquid chromatography.

    Science.gov (United States)

    Bai, Jingyao; Wang, Hongwei; Ou, Junjie; Liu, Zhongshan; Shen, Yehua; Zou, Hanfa

    2016-06-21

    A facile approach was exploited for fast preparation of polymer-based monoliths in UV-transparent fused-silica capillaries via "one-pot" photo-initiated thiol-acrylate polymerization reaction of dipentaerythritolpenta-/hexaacrylate (DPEPA) and 1-octadecanethiol (ODT) in the presence of porogenic solvents (1-butanol and ethylene glycol). Due to relative insensitivity of oxygen inhibition in thiol-ene free-radical polymerization, the polymerization could be performed within 5 min. The effects of composition of prepolymerization solution on the morphology and permeability of poly(ODT-co-DPEPA) monoliths were investigated in detail by adjusting the content of monomer and binary porogen ratio. The physical properties of poly(ODT-co-DPEPA) monoliths were characterized by Fourier transform infrared spectroscopy (FT-IR), mercury intrusion porosimetry (MIP) and nitrogen adsorption/desorption measurement. The evaluation of chromatographic performance was carried out by capillary liquid chromatography (cLC). The results indicated that the poly(ODT-co-DPEPA) monolith was homogeneous and permeable, and also possessed a typical reversed-phase retention mechanism in cLC with high efficiency (∼75,000 N m(-1)) for separation of alkylbenzenes. Eventually, the further separation of tryptic digest of proteins by cLC tandem mass spectrometry (cLC-MS/MS) demonstrated its potential in the analysis of biological samples.

  10. SILICA SURFACED CARBON FIBERS.

    Science.gov (United States)

    carbon fibers . Several economical and simple processes were developed for obtaining research quantities of silica surfaced carbon filaments. Vat dipping processes were utilized to deposit an oxide such as silica onto the surface and into the micropores of available carbon or graphite base fibers. High performance composite materials were prepared with the surface treated carbon fibers and various resin matrices. The ablative characteristics of these composites were very promising and exhibited fewer limitations than either silica or...treated

  11. Development of Hybrid and Monolithic Silicon Micropattern Detectors

    CERN Multimedia

    Beker, H; Snoeys, W; Campbell, M; Lemeilleur, F; Ropotar, I

    2002-01-01

    %RD-19 \\\\ \\\\ In a collaborative effort between particle physics institutes and microelectronics industry we are undertaking the development of true 2-dimensional semiconductor particle detectors with on-chip signal processing and information extraction: the so-called micropattern detector. This detector is able to cope in a robust way with high multiplicity events at high rates, while allowing for a longer detector lifetime under irradiation and a thinner sensitive depletion region. Therefore, it will be ideally suited for the complicated events in the LHC p-p collider experiments. Following a $^{\\prime}$stepping stone$^{\\prime}$ approach several telescopes of pixel planes, totalling now 600 cm$^{2}$ with \\(>\\)~1~M elements have been used in the WA97, NA50 and NA57 lead ion experiments. This new technology has facilitated the tracking considerably (see Fig.1). Not only Si but also GaAs and possibly diamond matrices can be connected to the readout matrix. Tests with GaAs pixel detectors with the RD-19 readout ...

  12. Hybrid Metal/Electrolyte Monolithic Low Temperature SOFCs

    Science.gov (United States)

    2007-11-02

    atmosphere (7% H2 balanced with Ar). Strontium doped lanthanum manganate, La0.8Sr0.15MnO3 or LSM, was synthesized by a glycine-nitrate process. The... Materia 7.2 Sintering of YSZ and Sc10Ce1SZ knowledge of the sintering characteristics of the ceram tal phase to match the sintering of the ceramic. Y

  13. Graphene oxide wrapping on squaraine-loaded mesoporous silica nanoparticles for bioimaging.

    Science.gov (United States)

    Sreejith, Sivaramapanicker; Ma, Xing; Zhao, Yanli

    2012-10-24

    Squaraine dyes were loaded inside mesoporous silica nanoparticles, and the nanoparticle surfaces were then wrapped with ultrathin graphene oxide sheets, leading to the formation of a novel hybrid material. The hybrid exhibits remarkable stability and can efficiently protect the loaded dye from nucleophilic attack. The biocompatible hybrid is noncytotoxic and presents significant potential for application in fluorescence imaging in vitro.

  14. Silica in higher plants.

    Science.gov (United States)

    Sangster, A G; Hodson, M J

    1986-01-01

    Opaline silica deposits are formed by many vascular (higher) plants. The capacity of these plants for silica absorption varies considerably according to genotype and environment. Plant communities exchange silica between soil and vegetation, especially in warmer climates. Silica deposition in epidermal cell walls offers mechanical and protective advantages. Biogenic silica particles from plants are also implicated in the causation of cancer. Recent techniques are reviewed which may aid in the identification of plant pathways for soluble silica movement to deposition sites and in the determination of ionic environments. Botanical investigations have focused on silicification of cell walls in relation to plant development, using scanning and transmission electron microscopy combined with X-ray microanalysis. Silica deposition in macrohair walls of the lemma of canary grass (Phalaris) begins at inflorescence emergence and closely follows wall thickening. The structure of the deposited silica may be determined by specific organic polymers present at successive stages of wall development. Lowering of transpiration by enclosure of Phalaris inflorescences in plastic bags reduced silica deposition in macrohairs. Preliminary freeze-substitution studies have located silicon, as well as potassium and chloride, in the cell vacuole and wall deposition sites during initial silicification.

  15. All-silica nanofluidic devices for DNA-analysis fabricated by imprint of sol-gel silica with silicon stamp

    DEFF Research Database (Denmark)

    Mikkelsen, Morten Bo Lindholm; Letailleur, Alban A; Søndergård, Elin

    2011-01-01

    We present a simple and cheap method for fabrication of silica nanofluidic devices for single-molecule studies. By imprinting sol-gel materials with a multi-level stamp comprising micro- and nanofeatures, channels of different depth are produced in a single process step. Calcination of the imprin......We present a simple and cheap method for fabrication of silica nanofluidic devices for single-molecule studies. By imprinting sol-gel materials with a multi-level stamp comprising micro- and nanofeatures, channels of different depth are produced in a single process step. Calcination...... of the imprinted hybrid sol-gel material produces purely inorganic silica, which has very low autofluorescence and can be fusion bonded to a glass lid. Compared to top-down processing of fused silica or silicon substrates, imprint of sol-gel silica enables fabrication of high-quality nanofluidic devices without...

  16. Synthesis and characterization of silicon-based polymers for use as organic/inorganic hybrids and silicon carbide precursors

    Science.gov (United States)

    Sellinger, Alan

    Organic/inorganic hybrids from silsesquioxanes. This Dissertation describes the synthesis and characterization of methacrylate, epoxy and liquid crystalline (LC)-containing organic/inorganic hybrid materials based on silsesquioxanes. While the methacrylate and epoxy groups provide polymerizable moieties to the hybrids, the LC component is anticipated to provide toughness, and oxidative stability as well as minimize shrinkage during curing. The inorganic silsesquioxane portion, ((RSiOsb{1.5})sb8, cubes), which closely resembles specific crystalline forms of silica and zeolites, may be covalently linked to a variety of organic functional groups. As a result, single-phase organic/inorganic hybrids are formed that when polymerized mimic silica-reinforced composites. The resultant hybrids are liquids at room temperature, and hence allow for single-phase composite processing, ideal for abrasion-resistant coatings and filling molds, as in dental restorative applications. The reactions are based on inexpensive starting materials, have high yields (>80%), and form soluble products containing up to 65% masked silica. The hybrids were characterized using NMR spectroscopy (sp1H,\\ sp{13}C,\\ sp{29}Si), FTIR, size exclusion chromatography (SEC), and thermal analysis (TGA, DSC). A modified polymethylsilane as a precursor of silicon carbide. It is generally known that polymer precursor routes to silicon carbide (SiC) are very important in the processing of SiC fibers and high performance SiC parts with specific shapes. It is further known that commercial SiC precursor polymers are often not resistant to oxidation, and are based on monomers rich in carbon. As a result of this, their pyrolysis yields SiC rich in oxygen and carbon, a feature which drastically reduces the final materials' ultimate properties (high temperature resistance, tensile strength, modulus). To remedy this, we describe in this work the synthesis and characterization of a modified polymethylsilane (mPMS) which

  17. Monolithic Integration of GaN-based LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Ao, Jin-Ping, E-mail: jpao@ee.tokushima-u.ac.jp [Institute of Technology and Science, University of Tokushima 2-1 Minami-Josanjima, Tokushima 770-8506 (Japan)

    2011-02-01

    The technology of monolithically integrated GaN-based light-emitting diodes (LEDs) is reported. First, the technology details to realize monolithic integration are described, including the circuit design for high-voltage and alternating current (AC) operation and the technologies for device isolation. The performances of the fabricated monolithic LED arrays are then demonstrated. A monolithic series array with totally 40 LEDs exhibited expected operation function under AC bias. The operation voltage of the array is 72 V when 20 LEDs were connected in series. Some modified circuit designs for high-voltage operation and other monolithic LED arrays are finally reviewed.

  18. Monolithic resonant optical reflector laser diodes

    Science.gov (United States)

    Hirata, T.; Suehiro, M.; Maeda, M.; Hihara, M.; Hosomatsu, H.

    1991-10-01

    The first monolithic resonant optical reflector laser diode that has a waveguide directional coupler and two DBR reflectors integrated by compositional disordering of quantum-well heterostructures is described. A linewidth of 440 kHz was obtained, and this value is expected to be greatly decreased by reducing the propagation loss in the integrated waveguide.

  19. Constant capacitance in nanopores of carbon monoliths.

    Science.gov (United States)

    García-Gómez, Alejandra; Moreno-Fernández, Gelines; Lobato, Belén; Centeno, Teresa A

    2015-06-28

    The results obtained for binder-free electrodes made of carbon monoliths with narrow micropore size distributions confirm that the specific capacitance in the electrolyte (C2H5)4NBF4/acetonitrile does not depend significantly on the micropore size and support the foregoing constant result of 0.094 ± 0.011 F m(-2).

  20. Direct tandem mass spectrometric analysis of amino acids in plasma using fluorous derivatization and monolithic solid-phase purification.

    Science.gov (United States)

    Tamashima, Erina; Hayama, Tadashi; Yoshida, Hideyuki; Imakyure, Osamu; Yamaguchi, Masatoshi; Nohta, Hitoshi

    2015-11-10

    In this study, we developed a novel direct tandem mass spectrometric method for rapid and accurate analysis of amino acids utilizing a fluorous derivatization and purification technique. Amino acids were perfluoroalkylated with 2H,2H,3H,3H-perfluoroundecan-1-al in the presence of 2-picoline borane via reductive amination. The derivatives were purified by perfluoroalkyl-modified silica-based monolithic solid-phase extraction (monolithic F-SPE), and directly analyzed by tandem mass spectrometry using electrospray ionization without liquid chromatographic separation. The perfluoroalkyl derivatives could be sufficiently distinguished from non-fluorous compounds, i.e. the biological matrix, due to their fluorous interaction. Thus, rapid and accurate determination of amino acids was accomplished. The method was validated with human plasma samples and applied to the analysis of amino acids in the plasma of mice with maple syrup urine disease or phenylketonuria.

  1. Magnetic hydrophobic nanocomposites: Silica aerogel/maghemite

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza Zelis, P. [Departamento de Fisica-IFLP, Universidad Nacional de La Plata-CONICET (Argentina); Fernandez van Raap, M.B., E-mail: raap@fisica.unlp.edu.ar [Departamento de Fisica-IFLP, Universidad Nacional de La Plata-CONICET (Arge