SnO2 Nanoparticles Decorated 2D Wavy Hierarchical Carbon Nanowalls with Enhanced Photoelectrochemical Performance

Directory of Open Access Journals (Sweden)

Noor Hamizah Khanis

2017-01-01

Full Text Available Two-dimensional carbon nanowall (2D-CNW structures were prepared by hot wire assisted plasma enhanced chemical vapor deposition (hw-PECVD system on silicon substrates. Controlled variations in the film structure were observed with increase in applied rf power during deposition which has been established to increase the rate of dissociation of precursor gases. The structural changes resulted in the formation of wavy-like features on the 2D-CNW, thus further enhancing the surface area of the nanostructures. The FESEM results confirmed the morphology transformation and conclusively showed the evolution of the 2D-CNW novel structures while Raman results revealed increase in ID/IG ratio indicating increase in the presence of disordered domains due to the presence of open edges on the 2D-CNW structures. Subsequently, the best 2D-CNW based on the morphology and structural properties was functionalized with tin oxide (SnO2 nanoparticles and used as a working electrode in a photoelectrochemical (PEC measurement system. Intriguingly, the SnO2 functionalized 2D-CNW showed enhancement in both Mott-Schottky profiles and LSV properties which suggested that these hierarchical networks showed promising potential application as effective charge-trapping medium in PEC systems.

Nanoscale Analysis of a Hierarchical Hybrid Solar Cell in 3D.

Science.gov (United States)

Divitini, Giorgio; Stenzel, Ole; Ghadirzadeh, Ali; Guarnera, Simone; Russo, Valeria; Casari, Carlo S; Bassi, Andrea Li; Petrozza, Annamaria; Di Fonzo, Fabio; Schmidt, Volker; Ducati, Caterina

2014-05-01

A quantitative method for the characterization of nanoscale 3D morphology is applied to the investigation of a hybrid solar cell based on a novel hierarchical nanostructured photoanode. A cross section of the solar cell device is prepared by focused ion beam milling in a micropillar geometry, which allows a detailed 3D reconstruction of the titania photoanode by electron tomography. It is found that the hierarchical titania nanostructure facilitates polymer infiltration, thus favoring intermixing of the two semiconducting phases, essential for charge separation. The 3D nanoparticle network is analyzed with tools from stochastic geometry to extract information related to the charge transport in the hierarchical solar cell. In particular, the experimental dataset allows direct visualization of the percolation pathways that contribute to the photocurrent.

Combustion synthesized hierarchically porous WO{sub 3} for selective acetone sensing

Energy Technology Data Exchange (ETDEWEB)

Dong, Chengjun; Liu, Xu; Guan, Hongtao; Chen, Gang; Xiao, Xuechun [Department of Materials Science and Engineering, Yunnan University, 650091, Kunming (China); Djerdj, Igor [Ruđer Bošković Institute, Bijenička 54, 10000, Zagreb (Croatia); Wang, Yude, E-mail: ydwang@ynu.edu.cn [Department of Materials Science and Engineering, Yunnan University, 650091, Kunming (China); Yunnan Province Key Lab of Mico-Nano Materials and Technology, Yunnan University, 650091, Kunming (China)

2016-12-01

An easy, inexpensive combustion route was designed to synthesize hierarchically porous WO{sub 3}. The tungsten source was fresh peroxiotungstic acid by dissolving tungsten powder into hydrogen peroxide. To promote the combustion reaction, a combined fuel of both glycine and hydrazine hydrate was used. The microstructure was well-connected pores comprised of subunit nanoparticles. Upon exposing towards acetone gas, the porous WO{sub 3} based sensor exhibits high gas response, rapid response and recovery, and good selectivity in the range of 5–1000 ppm under working temperature of 300 °C. This excellent sensing performance was plausibly attributed to the porous morphology, which hence provides more active sites for the gas molecules' reaction. - Graphical abstract: Hierarchically porous WO{sub 3} synthesized by combustion process exhibits high gas response, rapid response and recovery, and excellent selectivity for acetone, making it to be promising candidates for practical detectors for acetone. - Highlights: • Hierarchically porous WO{sub 3} synthesized by combustion process. • Hierarchically porous WO{sub 3} exhibits high gas response and excellent selectivity for acetone. • The excellent sensing property was plausibly attributed to the porous morphology.

Hierarchically nanostructured hydroxyapatite: hydrothermal synthesis, morphology control, growth mechanism, and biological activity

Science.gov (United States)

Ma, Ming-Guo

2012-01-01

Hierarchically nanosized hydroxyapatite (HA) with flower-like structure assembled from nanosheets consisting of nanorod building blocks was successfully synthesized by using CaCl2, NaH2PO4, and potassium sodium tartrate via a hydrothermal method at 200°C for 24 hours. The effects of heating time and heating temperature on the products were investigated. As a chelating ligand and template molecule, the potassium sodium tartrate plays a key role in the formation of hierarchically nanostructured HA. On the basis of experimental results, a possible mechanism based on soft-template and self-assembly was proposed for the formation and growth of the hierarchically nanostructured HA. Cytotoxicity experiments indicated that the hierarchically nanostructured HA had good biocompatibility. It was shown by in-vitro experiments that mesenchymal stem cells could attach to the hierarchically nanostructured HA after being cultured for 48 hours. Objective The purpose of this study was to develop facile and effective methods for the synthesis of novel hydroxyapatite (HA) with hierarchical nanostructures assembled from independent and discrete nanobuilding blocks. Methods A simple hydrothermal approach was applied to synthesize HA by using CaCl2, NaH2PO4, and potassium sodium tartrate at 200°C for 24 hours. The cell cytotoxicity of the hierarchically nanostructured HA was tested by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Results HA displayed the flower-like structure assembled from nanosheets consisting of nanorod building blocks. The potassium sodium tartrate was used as a chelating ligand, inducing the formation and self-assembly of HA nanorods. The heating time and heating temperature influenced the aggregation and morphology of HA. The cell viability did not decrease with the increasing concentration of hierarchically nanostructured HA added. Conclusion A novel, simple and reliable hydrothermal route had been developed for the synthesis of

Hierarchical self-assembly of PDMA-b-PS chains into granular nanoparticles: genesis and fate.

Science.gov (United States)

Bianchi, Alberto; Mauri, Michele; Bonetti, Simone; Koynov, Kaloian; Kappl, Michael; Lieberwirth, Ingo; Butt, Hans-Jürgen; Simonutti, Roberto

2014-12-01

The hierarchical self-assembly of an amphiphilic block copolymer, poly(N,N-dimethylacrylamide)-block-polystyrene with a very short hydrophilic block (PDMA10 -b-PS62 ), in large granular nanoparticles is reported. While these nanoparticles are stable in water, their disaggregation can be induced either mechanically (i.e., by applying a force via the tip of the cantilever of an atomic force microscope (AFM)) or by partial hydrolysis of the acrylamide groups. AFM force spectroscopy images show the rupture of the particle as a combination of collapse and flow, while scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images of partly hydrolyzed nanoparticles provide a clear picture of the granular structure. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hierarchically nanostructured hydroxyapatite: hydrothermal synthesis, morphology control, growth mechanism, and biological activity

Directory of Open Access Journals (Sweden)

Ma MG

2012-04-01

Full Text Available Ming-Guo MaInstitute of Biomass Chemistry and Technology, College of Materials Science and Technology, Beijing Forestry University, Beijing, People's Republic of ChinaAbstract: Hierarchically nanosized hydroxyapatite (HA with flower-like structure assembled from nanosheets consisting of nanorod building blocks was successfully synthesized by using CaCl2, NaH2PO4, and potassium sodium tartrate via a hydrothermal method at 200°C for 24 hours. The effects of heating time and heating temperature on the products were investigated. As a chelating ligand and template molecule, the potassium sodium tartrate plays a key role in the formation of hierarchically nanostructured HA. On the basis of experimental results, a possible mechanism based on soft-template and self-assembly was proposed for the formation and growth of the hierarchically nanostructured HA. Cytotoxicity experiments indicated that the hierarchically nanostructured HA had good biocompatibility. It was shown by in-vitro experiments that mesenchymal stem cells could attach to the hierarchically nanostructured HA after being cultured for 48 hours.Objective: The purpose of this study was to develop facile and effective methods for the synthesis of novel hydroxyapatite (HA with hierarchical nanostructures assembled from independent and discrete nanobuilding blocks.Methods: A simple hydrothermal approach was applied to synthesize HA by using CaCl2, NaH2PO4, and potassium sodium tartrate at 200°C for 24 hours. The cell cytotoxicity of the hierarchically nanostructured HA was tested by MTT (3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay.Results: HA displayed the flower-like structure assembled from nanosheets consisting of nanorod building blocks. The potassium sodium tartrate was used as a chelating ligand, inducing the formation and self-assembly of HA nanorods. The heating time and heating temperature influenced the aggregation and morphology of HA. The cell viability did

Synthesis of hierarchical anatase TiO 2 nanostructures with tunable morphology and enhanced photocatalytic activity

KAUST Repository

Rahal, Raed; Wankhade, Atul V.; Cha, Dong Kyu; Fihri, Aziz; Ould-Chikh, Samy; Patil, Umesh; Polshettiwar, Vivek

2012-01-01

A facile one-pot method to prepare three-dimensional hierarchical nanostructures of titania with good control over their morphologies without the use of hydrofluoric acid is developed. The reaction is performed under microwave irradiation conditions in pure water, and enables enhanced photocatalytic activity. This study indicates that photocatalytic activity depends not only on the surface area but also on the morphology of the titania. © 2012 The Royal Society of Chemistry.

Morphological evolution of copper nanoparticles: Microemulsion reactor system versus batch reactor system

Science.gov (United States)

Xia, Ming; Tang, Zengmin; Kim, Woo-Sik; Yu, Taekyung; Park, Bum Jun

2017-07-01

In the synthesis of nanoparticles, the reaction rate is important to determine the morphology of nanoparticles. We investigated morphology evolution of Cu nanoparticles in this two different reactors, microemulsion reactor and batch reactor. In comparison with the batch reactor system, the enhanced mass and heat transfers in the emulsion system likely led to the relatively short nucleation time and the highly homogeneous environment in the reaction mixture, resulting in suppressing one or two dimensional growth of the nanoparticles. We believe that this work can offer a good model system to quantitatively understand the crystal growth mechanism that depends strongly on the local monomer concentration, the efficiency of heat transfer, and the relative contribution of the counter ions (Br- and Cl-) as capping agents.

Morphological quantification of hierarchical geomaterials by X-ray nano-CT bridges the gap from nano to micro length scales

KAUST Repository

Brisard, S.; Chae, R. S.; Bihannic, I.; Michot, L.; Guttmann, P.; Thieme, J.; Schneider, G.; Monteiro, P. J. M.; Levitz, P.

2012-01-01

Morphological quantification of the complex structure of hierarchical geomaterials is of great relevance for Earth science and environmental engineering, among others. To date, methods that quantify the 3D morphology on length scales ranging from a

Hierarchical Mesoporous Organosilica-Silica Core-Shell Nanoparticles Capable of Controlled Fungicide Release.

Science.gov (United States)

Luo, Leilei; Liang, Yucang; Erichsen, Egil Severin; Anwander, Reiner

2018-05-17

A new class of hierarchically structured mesoporous silica core-shell nanoparticles (HSMSCSNs) with a periodic mesoporous organosilica (PMO) core and a mesoporous silica (MS) shell is reported. The applied one-pot, two-step strategy allows rational control over the core/shell chemical composition, topology, and pore/particle size, simply by adjusting the reaction conditions in the presence of cetyltrimethylammonium bromide (CTAB) as structure-directing agent under basic conditions. The spherical, ethylene- or methylene-bridged PMO cores feature hexagonal (p6mm) or cage-like cubic symmetry (Pm3‾ n) depending on the organosilica precursor. The hexagonal MS shell was obtained by n-hexane-induced controlled hydrolysis of TEOS followed by directional co-assembly/condensation of silicate/CTAB composites at the PMO cores. The HSMSCSNs feature a hierarchical pore structure with pore diameters of about 2.7 and 5.6 nm in the core and shell domains, respectively. The core sizes and shell thicknesses are adjustable in the ranges of 90-275 and 15-50 nm, respectively, and the surface areas (max. 1300 m 2  g -1 ) and pore volumes (max. 1.83 cm 3  g -1 ) are among the highest reported for core-shell nanoparticles. The adsorption and controlled release of the fungicide propiconazole by the HSMSCSNs showed a three-stage release profile. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of Superhydrophobic Surface with Controlled Wetting Property by Hierarchical Particles.

Science.gov (United States)

Xu, Jianxiong; Liu, Weiwei; Du, Jingjing; Tang, Zengmin; Xu, Lijian; Li, Na

2015-04-01

Hierarchical particles were prepared by synthetically joining appropriately functionalized polystyrene spheres of poly[styrene-co-(3-(4-vinylphenyl)pentane-2,4-dione)] (PS-co-PVPD) nanoparticles and poly(styrene-co-chloromethylstyrene) (PS-co-PCMS) microparticles. The coupling reaction of nucleophilic substitution of pendent β-diketone groups with benzyl chloride was used to form the hierarchical particles. Since the polymeric nanoparticles and microparticles were synthesized by dispersion polymerization and emulsion polymerization, respectively, both the core microparticles and the surface nanoparticles can be different size and chemical composition. By means of changing the size of the PS-co-PVPD surface nanoparticles, a series of hierarchical particles with different scale ratio of the micro/nano surface structure were successfully prepared. Moreover, by employing the PS-co-PVPD microparticles and PS-co-PCMS nanoparticles as building blocks, hierarchical particles with surface nanoaprticles of different composition were made. These as-prepared hierarchical particles were subsequently assembled on glass substrates to form particulate films. Contact angle measurement shows that superhydrophobic surfaces can be obtained and the contact angle of water on the hierarchically structured surface can be adjusted by the scale ratio of the micro/nano surface structure and surface chemical component of hierarchical particles.

Size and morphology controlled NiSe nanoparticles as efficient catalyst for the reduction reactions

Energy Technology Data Exchange (ETDEWEB)

Subbarao, Udumula; Marakatti, Vijaykumar S. [New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064 (India); Amshumali, Mungalimane K. [New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064 (India); Department of Chemistry and Industrial Chemistry, Vijayanagara Sri Krishnadevaraya University, Jnanasagara Campus, Cantonment, Bellary 583105 (India); Loukya, B. [International Center for Materials Science, Jakkur P.O., Bangalore 560064 (India); Singh, Dheeraj Kumar [Chemistry & Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064 (India); Datta, Ranjan [International Center for Materials Science, Jakkur P.O., Bangalore 560064 (India); Peter, Sebastian C., E-mail: sebastiancp@jncasr.ac.in [New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064 (India)

2016-12-15

Facile and efficient ball milling and polyol methods were employed for the synthesis of nickel selenide (NiSe) nanoparticle. The particle size of the NiSe nanoparticle has been controlled mechanically by varying the ball size in the milling process. The role of the surfactants in the formation of various morphologies was studied. The compounds were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray energy dispersive spectroscopy (EDS). The efficiency of the NiSe nanoparticle as a catalyst was tested for the reduction of para-nitroaniline (PNA) to para-phenyldiamine (PPD) and para-nitrophenol (PNP) to para-aminophenol (PAP) using NaBH{sub 4} as the reducing agent. Particle size, morphology and the presence of surfactant played a crucial role in the reduction process. - Graphical abstract: NiSe nanoparticles in different size and morphology were synthesized using facile ball milling and polyol methods. Particle size, morphology and the presence of surfactant in these materials played a crucial role in the hydrogenation of PNA and PNP. - Highlights: • NiSe nanoparticles synthesized using ball milling and solution phase methods. • NiSe nanoparticle is an efficient catalyst for the reduction of PNA and PNP. • NiSe is found to be better than the best reported noble metal catalysts.

Size and morphology controlled NiSe nanoparticles as efficient catalyst for the reduction reactions

International Nuclear Information System (INIS)

Subbarao, Udumula; Marakatti, Vijaykumar S.; Amshumali, Mungalimane K.; Loukya, B.; Singh, Dheeraj Kumar; Datta, Ranjan; Peter, Sebastian C.

2016-01-01

Facile and efficient ball milling and polyol methods were employed for the synthesis of nickel selenide (NiSe) nanoparticle. The particle size of the NiSe nanoparticle has been controlled mechanically by varying the ball size in the milling process. The role of the surfactants in the formation of various morphologies was studied. The compounds were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray energy dispersive spectroscopy (EDS). The efficiency of the NiSe nanoparticle as a catalyst was tested for the reduction of para-nitroaniline (PNA) to para-phenyldiamine (PPD) and para-nitrophenol (PNP) to para-aminophenol (PAP) using NaBH 4 as the reducing agent. Particle size, morphology and the presence of surfactant played a crucial role in the reduction process. - Graphical abstract: NiSe nanoparticles in different size and morphology were synthesized using facile ball milling and polyol methods. Particle size, morphology and the presence of surfactant in these materials played a crucial role in the hydrogenation of PNA and PNP. - Highlights: • NiSe nanoparticles synthesized using ball milling and solution phase methods. • NiSe nanoparticle is an efficient catalyst for the reduction of PNA and PNP. • NiSe is found to be better than the best reported noble metal catalysts.

Hierarchical pulmonary target nanoparticles via inhaled administration for anticancer drug delivery.

Science.gov (United States)

Chen, Rui; Xu, Liu; Fan, Qin; Li, Man; Wang, Jingjing; Wu, Li; Li, Weidong; Duan, Jinao; Chen, Zhipeng

2017-11-01

Inhalation administration, compared with intravenous administration, significantly enhances chemotherapeutic drug exposure to the lung tissue and may increase the therapeutic effect for pulmonary anticancer. However, further identification of cancer cells after lung deposition of inhaled drugs is necessary to avoid side effects on normal lung tissue and to maximize drug efficacy. Moreover, as the action site of the major drug was intracellular organelles, drug target to the specific organelle is the final key for accurate drug delivery. Here, we designed a novel multifunctional nanoparticles (MNPs) for pulmonary antitumor and the material was well-designed for hierarchical target involved lung tissue target, cancer cell target, and mitochondrial target. The biodistribution in vivo determined by UHPLC-MS/MS method was employed to verify the drug concentration overwhelmingly increasing in lung tissue through inhaled administration compared with intravenous administration. Cellular uptake assay using A549 cells proved the efficient receptor-mediated cell endocytosis. Confocal laser scanning microscopy observation showed the location of MNPs in cells was mitochondria. All results confirmed the intelligent material can progressively play hierarchical target functions, which could induce more cell apoptosis related to mitochondrial damage. It provides a smart and efficient nanocarrier platform for hierarchical targeting of pulmonary anticancer drug. So far, this kind of material for pulmonary mitochondrial-target has not been seen in other reports.

One-Pot and Facile Fabrication of Hierarchical Branched Pt-Cu Nanoparticles as Excellent Electrocatalysts for Direct Methanol Fuel Cells.

Science.gov (United States)

Cao, Yanqin; Yang, Yong; Shan, Yufeng; Huang, Zhengren

2016-03-09

Hierarchical branched nanoparticles are one promising nanostructure with three-dimensional open porous structure composed of integrated branches for superior catalysis. We have successfully synthesized Pt-Cu hierarchical branched nanoparticles (HBNDs) with small size of about 30 nm and composed of integrated ultrathin branches by using a modified polyol process with introduction of poly(vinylpyrrolidone) and HCl. This strategy is expected to be a general strategy to prepare various metallic nanostructures for catalysis. Because of the special open porous structure, the as-prepared Pt-Cu HBNDs exhibit greatly enhanced specific activity toward the methanol oxidation reaction as much as 2.5 and 1.7 times compared with that of the commercial Pt-Ru and Pt-Ru/C catalysts, respectively. Therefore, they are potentially applicable as electrocatalysts for direct methanol fuel cells.

Morphological changes of the red blood cells treated with metal oxide nanoparticles.

Science.gov (United States)

Kozelskaya, A I; Panin, A V; Khlusov, I A; Mokrushnikov, P V; Zaitsev, B N; Kuzmenko, D I; Vasyukov, G Yu

2016-12-01

The toxic effect of Al 2 O 3 , SiО 2 and ZrО 2 nanoparticles on red blood cells of Wistar rats was studied in vitro using the atomic force microscopy and the fluorescence analysis. Transformation of discocytes into echinocytes and spherocytes caused by the metal oxide nanoparticles was revealed. It was shown that only extremely high concentration of the nanoparticles (2mg/ml) allows correct estimating of their effect on the cell morphology. Besides, it was found out that the microviscosity changes of red blood cell membranes treated with nanoparticles began long before morphological modifications of the cells. On the contrary, the negatively charged ZrO 2 and SiO 2 nanoparticles did not affect ghost microviscosity up to concentrations of 1μg/ml and 0.1mg/ml, correspondingly. In its turn, the positively charged Al 2 O 3 nanoparticles induced structural changes in the lipid bilayer of the red blood cells already at a concentration of 0.05μg/ml. A decrease in microviscosity of the erythrocyte ghosts treated with Al 2 O 3 and SiO 2 nanoparticles was shown. It was detected that the interaction of ZrO 2 nanoparticles with the cells led to an increase in the membrane microviscosity and cracking of swollen erythrocytes. Copyright © 2016 Elsevier B.V. All rights reserved.

Surface-spin magnetism of antiferromagnetic NiO in nanoparticle and bulk morphology

International Nuclear Information System (INIS)

Jagodic, M; Jaglicic, Z; Jelen, A; Dolinsek, J; Lee, Jin Bae; Kim, Hae Jin; Kim, Young-Min

2009-01-01

The surface-spin magnetism of the antiferromagnetic (AFM) material NiO in nanoparticle and bulk morphology was investigated by magnetic measurements (temperature-dependent zero-field-cooled (zfc) and field-cooled (fc) dc susceptibility, ac susceptibility and zfc and fc hysteresis loops). We addressed the question of whether the multisublattice ordering of the uncompensated surface spins and the exchange bias (EB) effect are only present in the nanoparticles, originating from their high surface-to-volume ratio or if these surface phenomena are generally present in the AFM materials regardless of their bulky or nanoparticle morphology, but the effect is just too small to be detected experimentally in the bulk due to a very small surface magnetization. Performing experiments on the NiO nanoparticles of different sizes and bulk NiO grains, we show that coercivity enhancement and hysteresis loop shift in the fc experiments, considered to be the key experimental manifestations of multisublattice ordering and the EB effect, are true nanoscale phenomena only present in the nanoparticles and absent in the bulk.

Hierarchical TiN nanoparticles-assembled nanopillars for flexible supercapacitors with high volumetric capacitance.

Science.gov (United States)

Qin, Ping; Li, Xingxing; Gao, Biao; Fu, Jijiang; Xia, Lu; Zhang, Xuming; Huo, Kaifu; Shen, Wenli; Chu, Paul K

2018-05-10

Titanium nitride (TiN) is an attractive electrode material in fast charging/discharging supercapacitors because of its excellent conductivity. However, the low capacitance and mechanical brittleness of TiN restricts its further application in flexible supercapacitors with high energy density. Thus, it is still a challenge to rationally design TiN electrodes with both high electrochemical and mechanical properties. Herein, the hierarchical TiN nanoparticles-assembled nanopillars (H-TiN NPs) array as binder free electrodes were obtained by nitriding of hierarchical titanium dioxide (TiO2) nanopillars, which was produced by a simple hydrothermal treatment of anodic TiO2 nanotubes (NTs) array in water. The porous TiN nanoparticles connected to each other to form ordered nanopillar arrays, effectively providing larger specific surface area and more active sites for charge storage. The H-TiN NPs delivered a high volumetric capacitance of 120 F cm-3 at 0.83 A cm-3, which is better than that of TiN NTs arrays (69 F cm-3 at 0.83 A cm-3). After assembling into all-solid-state devices, the H-TiN NPs based supercapacitors exhibited outstanding volumetric capacitance of 5.9 F cm-3 at 0.02 A cm-3 and a high energy density of 0.53 mW h cm-3. Our results reveal a new strategy to optimize the supercapacitive performance of metal nitrides.

Morphology-dependent activity of Pt nanocatalysts for ethanol oxidation in acidic media: Nanowires versus nanoparticles

International Nuclear Information System (INIS)

Zhou Weiping; Li Meng; Koenigsmann, Christopher; Ma Chao; Wong, Stanislaus S.; Adzic, Radoslav R.

2011-01-01

Highlights: → We demonstrate the morphology effect of Pt catalysts in electrooxidation of ethanol and CO in an acidic solution. → Pt nanowires and nanoparticles were used as catalysts. → Pt nanowires display a higher catalytic activity by a factor of at least two relative to those nanoparticles for ethanol oxidation. → The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. - Abstract: The morphology of nanostructured Pt catalysts is known to affect significantly the kinetics of various reactions. Herein, we report on a pronounced morphology effect in the electrooxidation of ethanol and carbon monoxide (CO) on Pt nanowires and nanoparticles in an acidic solution. The high resolution transmission electron microscopy analysis showed the inherent morphology difference between these two nanostructured catalysts. Voltammetric and chronoamperometric studies of the ethanol electrooxidation revealed that these nanowires had a higher catalytic activity by a factor of two relative to these nanoparticles. The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. In situ infrared reflection-absorption spectroscopy measurements revealed a different trend for chemisorbed CO formation and CO 2 -to-acetic acid reaction product ratios on these two nanostructures. The morphology-induced change in catalytic activity and selectivity in ethanol electrocatalysis is discussed in detail.

Morphology-dependent activity of Pt nanocatalysts for ethanol oxidation in acidic media: Nanowires versus nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Zhou Weiping, E-mail: wpzhou@bnl.gov [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Li Meng [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Koenigsmann, Christopher [Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794 (United States); Ma Chao [Condensed Matter Physics and Materials Sciences Department, Brookhaven National Laboratory, Building 480, Upton, NY 11973 (United States); Wong, Stanislaus S. [Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794 (United States); Condensed Matter Physics and Materials Sciences Department, Brookhaven National Laboratory, Building 480, Upton, NY 11973 (United States); Adzic, Radoslav R. [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2011-11-30

Highlights: > We demonstrate the morphology effect of Pt catalysts in electrooxidation of ethanol and CO in an acidic solution. > Pt nanowires and nanoparticles were used as catalysts. > Pt nanowires display a higher catalytic activity by a factor of at least two relative to those nanoparticles for ethanol oxidation. > The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. - Abstract: The morphology of nanostructured Pt catalysts is known to affect significantly the kinetics of various reactions. Herein, we report on a pronounced morphology effect in the electrooxidation of ethanol and carbon monoxide (CO) on Pt nanowires and nanoparticles in an acidic solution. The high resolution transmission electron microscopy analysis showed the inherent morphology difference between these two nanostructured catalysts. Voltammetric and chronoamperometric studies of the ethanol electrooxidation revealed that these nanowires had a higher catalytic activity by a factor of two relative to these nanoparticles. The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. In situ infrared reflection-absorption spectroscopy measurements revealed a different trend for chemisorbed CO formation and CO{sub 2}-to-acetic acid reaction product ratios on these two nanostructures. The morphology-induced change in catalytic activity and selectivity in ethanol electrocatalysis is discussed in detail.

CTAB-Assisted Hydrothermal Synthesis of WO3 Hierarchical Porous Structures and Investigation of Their Sensing Properties

Directory of Open Access Journals (Sweden)

Dan Meng

2015-01-01

Full Text Available WO3 hierarchical porous structures were successfully synthesized via cetyltrimethylammonium bromide- (CTAB- assisted hydrothermal method. The structure and morphology were investigated using scanning electron microscope, X-ray diffractometer, transmission electron microscopy, X-ray photoelectron spectra, Brunauer-Emmett-Teller nitrogen adsorption-desorption, and thermogravimetry and differential thermal analysis. The result demonstrated that WO3 hierarchical porous structures with an orthorhombic structure were constructed by a number of nanoparticles about 50–100 nm in diameters. The H2 gas sensing measurements showed that well-defined WO3 hierarchical porous structures with a large specific surface area exhibited the higher sensitivity compared with products without CTAB at all operating temperatures. Moreover, the reversible and fast response to H2 gas and good selectivity were obtained. The results indicated that the WO3 hierarchical porous structures are promising materials for gas sensors.

High-Performance Hydrogen Storage Nanoparticles Inside Hierarchical Porous Carbon Nanofibers with Stable Cycling.

Science.gov (United States)

Xia, Guanglin; Chen, Xiaowei; Zhao, Yan; Li, Xingguo; Guo, Zaiping; Jensen, Craig M; Gu, Qinfen; Yu, Xuebin

2017-05-10

An effective route based on space-confined chemical reaction to synthesize uniform Li 2 Mg(NH) 2 nanoparticles is reported. The hierarchical pores inside the one-dimensional carbon nanofibers (CNFs), induced by the creation of well-dispersed Li 3 N, serve as intelligent nanoreactors for the reaction of Li 3 N with Mg-containing precursors, resulting in the formation of uniformly discrete Li 2 Mg(NH) 2 nanoparticles. The nanostructured Li 2 Mg(NH) 2 particles inside the CNFs are capable of complete hydrogenation and dehydrogenation at a temperature as low as 105 °C with the suppression of ammonia release. Furthermore, by virtue of the nanosize effects and space-confinement by the porous carbon scaffold, no degradation was observed after 50 de/rehydrogenation cycles at a temperature as low as 130 °C for the as-prepared Li 2 Mg(NH) 2 nanoparticles, indicating excellent reversibility. Moreover, the theoretical calculations demonstrate that the reduction in particle size could significantly enhance the H 2 sorption of Li 2 Mg(NH) 2 by decreasing the relative activation energy barrier, which agrees well with our experimental results. This method could represent an effective, general strategy for synthesizing nanoparticles of complex hydrides with stable reversibility and excellent hydrogen storage performance.

Hierarchically structured lithium titanate for ultrafast charging in long-life high capacity batteries

Science.gov (United States)

Odziomek, Mateusz; Chaput, Frédéric; Rutkowska, Anna; Świerczek, Konrad; Olszewska, Danuta; Sitarz, Maciej; Lerouge, Frédéric; Parola, Stephane

2017-05-01

High-performance Li-ion batteries require materials with well-designed and controlled structures on nanometre and micrometre scales. Electrochemical properties can be enhanced by reducing crystallite size and by manipulating structure and morphology. Here we show a method for preparing hierarchically structured Li4Ti5O12 yielding nano- and microstructure well-suited for use in lithium-ion batteries. Scalable glycothermal synthesis yields well-crystallized primary 4-8 nm nanoparticles, assembled into porous secondary particles. X-ray photoelectron spectroscopy reveals presence of Ti+4 only; combined with chemical analysis showing lithium deficiency, this suggests oxygen non-stoichiometry. Electron microscopy confirms hierarchical morphology of the obtained material. Extended cycling tests in half cells demonstrates capacity of 170 mAh g-1 and no sign of capacity fading after 1,000 cycles at 50C rate (charging completed in 72 s). The particular combination of nanostructure, microstructure and non-stoichiometry for the prepared lithium titanate is believed to underlie the observed electrochemical performance of material.

Morphological effects on the selectivity of intramolecular versus intermolecular catalytic reaction on Au nanoparticles.

Science.gov (United States)

Wang, Dan; Sun, Yuanmiao; Sun, Yinghui; Huang, Jing; Liang, Zhiqiang; Li, Shuzhou; Jiang, Lin

2017-06-14

It is hard for metal nanoparticle catalysts to control the selectivity of a catalytic reaction in a simple process. In this work, we obtain active Au nanoparticle catalysts with high selectivity for the hydrogenation reaction of aromatic nitro compounds, by simply employing spine-like Au nanoparticles. The density functional theory (DFT) calculations further elucidate that the morphological effect on thermal selectivity control is an internal key parameter to modulate the nitro hydrogenation process on the surface of Au spines. These results show that controlled morphological effects may play an important role in catalysis reactions of noble metal NPs with high selectivity.

Morphology Control of Platinum Nanoparticles and their Catalytic Properties

International Nuclear Information System (INIS)

Miyazaki, Akane; Balint, Ioan; Nakano, Yoshio

2003-01-01

Platinum nanoparticles with different morphology were prepared by reduction of K 2 PtCl 4 solution in the presence of different capping polymers. It was found that the shapes and the sizes of the Pt nanocrystals resulted were related to the kind of capping polymer used. When poly(vinylpyrrolidon) (PVP), poly(N-isopropylacrylamide) (NIPA) and sodium poly(acrylate) (SPA) were used as capping agents, the dominant shapes of the Pt nanocrystals observed by transmission electron microscopy were hexagonal (∼62%), square (∼67%) and triangular (∼41%), respectively. The average sizes of Pt nanocrystals were 6.9, 13.6 and 14.6 nm for capping polymers of PVP, NIPA and SPA, respectively. The colloidal Pt nanoparticles with different morphologies were supported on γ-Al 2 O 3 (1 wt.% Pt) and then their catalytic activity for NO reduction by CH 4 was tested in the 350-600 deg. C temperature range. Additionally, the catalytic activities of these alumina-supported Pt nanocrystals were compared with a conventional catalyst having the average size of Pt particles of ∼2.4 nm. Over the alumina-supported Pt nanocrystals as compared with the conventional Pt/Al 2 O 3 , it was observed that the NO/CH 4 reaction yields to NH 3 and CO decreased significantly and on the other hand, the yield to N 2 O increased. The experimental results are suggesting that the catalytic behavior can be tuned in a convenient way through the morphological control of the metal nanoparticles

Morphology Control of Platinum Nanoparticles and their Catalytic Properties

Energy Technology Data Exchange (ETDEWEB)

Miyazaki, Akane [Tokyo Institute of Technology, Department of Environmental Chemistry and Engineering, Interdisciplinary Graduate School of Science and Technology (Japan)], E-mail: akanem@chemenv.titech.ac.jp; Balint, Ioan [Institute of Physical Chemistry, Romanian Academy (Romania); Nakano, Yoshio [Tokyo Institute of Technology, Department of Environmental Chemistry and Engineering, Interdisciplinary Graduate School of Science and Technology (Japan)

2003-04-15

Platinum nanoparticles with different morphology were prepared by reduction of K{sub 2}PtCl{sub 4} solution in the presence of different capping polymers. It was found that the shapes and the sizes of the Pt nanocrystals resulted were related to the kind of capping polymer used. When poly(vinylpyrrolidon) (PVP), poly(N-isopropylacrylamide) (NIPA) and sodium poly(acrylate) (SPA) were used as capping agents, the dominant shapes of the Pt nanocrystals observed by transmission electron microscopy were hexagonal ({approx}62%), square ({approx}67%) and triangular ({approx}41%), respectively. The average sizes of Pt nanocrystals were 6.9, 13.6 and 14.6 nm for capping polymers of PVP, NIPA and SPA, respectively. The colloidal Pt nanoparticles with different morphologies were supported on {gamma}-Al{sub 2}O{sub 3} (1 wt.% Pt) and then their catalytic activity for NO reduction by CH{sub 4} was tested in the 350-600 deg. C temperature range. Additionally, the catalytic activities of these alumina-supported Pt nanocrystals were compared with a conventional catalyst having the average size of Pt particles of {approx}2.4 nm. Over the alumina-supported Pt nanocrystals as compared with the conventional Pt/Al{sub 2}O{sub 3}, it was observed that the NO/CH{sub 4} reaction yields to NH{sub 3} and CO decreased significantly and on the other hand, the yield to N{sub 2}O increased. The experimental results are suggesting that the catalytic behavior can be tuned in a convenient way through the morphological control of the metal nanoparticles.

Organometallic synthesis of ZnO nanoparticles for gas sensing: towards selectivity through nanoparticles morphology

Energy Technology Data Exchange (ETDEWEB)

Ryzhikov, Andrey; Jońca, Justyna; Kahn, Myrtil; Fajerwerg, Katia [Laboratoire de Chimie de Coordination (LCC), CNRS (France); Chaudret, Bruno [Laboratoire de Physique et de Chimie de Nano-objets (LPCNO), INSA, UPS, CNRS (France); Chapelle, Audrey [Laboratoire d’Analyse et d’Architecture des Systèmes (LAAS), CNRS (France); Ménini, Philippe [Université Toulouse III, Paul Sabatier (France); Shim, Chang Hyun [Laboratoire d’Analyse et d’Architecture des Systèmes (LAAS), CNRS (France); Gaudon, Alain [Alpha M.O.S. SA (France); Fau, Pierre, E-mail: pierre.fau@lcc-toulouse.fr [Laboratoire de Chimie de Coordination (LCC), CNRS (France)

2015-07-15

ZnO nanoparticles (NP) with different morphologies such as nanorods (NR), isotropic NP, and cloud-like (CL) structures have been synthesized by an organometallic route. The prepared ZnO nanostructures have been deposited on miniaturized silicon gas sensor substrates by an inkjet method, and their responses to CO, C{sub 3}H{sub 8}, and NH{sub 3} gases have been studied at different operating temperatures (340–500 °C) and relative humidity of 50 %. It is noteworthy that the morphology of the nanostructure of the sensitive layer is maintained after thermal treatment. The morphology of ZnO NP significantly influences the sensor response level and their selectivity properties to reducing gases. Among the three different ZnO types, sensors prepared with NR show the highest response to both CO and C{sub 3}H{sub 8}. Sensors made of isotropic NP and CL structures show a lower but similar response to CO. From all investigated nanostructures, sensors made of CL structures show the weakest response to C{sub 3}H{sub 8}. With NH{sub 3} gas, no effect of the morphology of the ZnO sensitive layer has been evidenced. These different responses highlight the important role of the nanostructure of the ZnO sensitive layer and the nature of the target gas on the detection properties of the sensors. Graphical Abstract: Three different ZnO nanoparticles morphologies (cloud-like, dots, rods) have been employed as sensitive layers in chemoresistive sensors for the selective detection of CO, C{sub 3}H{sub 8} and NH{sub 3}.

MIL-100 derived nitrogen-embodied carbon shells embedded with iron nanoparticles

Science.gov (United States)

Mao, Chengyu; Kong, Aiguo; Wang, Yuan; Bu, Xianhui; Feng, Pingyun

2015-06-01

The use of metal-organic frameworks (MOFs) as templates and precursors to synthesize new carbon materials with controllable morphology and pre-selected heteroatom doping holds promise for applications as efficient non-precious metal catalysts. Here, we report a facile pyrolysis pathway to convert MIL-100 into nitrogen-doped carbon shells encapsulating Fe nanoparticles in a comparative study involving multiple selected nitrogen sources. The hierarchical porous architecture, embedded Fe nanoparticles, and nitrogen decoration endow this composite with a superior oxygen reduction activity. Furthermore, the excellent durability and high methanol tolerance even outperform the commercial Pt-C catalyst.The use of metal-organic frameworks (MOFs) as templates and precursors to synthesize new carbon materials with controllable morphology and pre-selected heteroatom doping holds promise for applications as efficient non-precious metal catalysts. Here, we report a facile pyrolysis pathway to convert MIL-100 into nitrogen-doped carbon shells encapsulating Fe nanoparticles in a comparative study involving multiple selected nitrogen sources. The hierarchical porous architecture, embedded Fe nanoparticles, and nitrogen decoration endow this composite with a superior oxygen reduction activity. Furthermore, the excellent durability and high methanol tolerance even outperform the commercial Pt-C catalyst. Electronic supplementary information (ESI) available: Material synthesis and elemental analysis, electrochemistry measurements, and additional figures. See DOI: 10.1039/c5nr02346g

Self-assembled 3D-hierarchical structure Cu2ZnSnS4 photocathodes by tuning anion ratios in precursor solution

International Nuclear Information System (INIS)

Wen, Xin; Shao, Hansen; Fu, Gao; Zhou, Yong; Zou, Zhigang; Luo, Wenjun; Guan, Zhongjie

2016-01-01

Cu 2 ZnSnS 4 (CZTS) is one of the most promising light capture materials for solar cells or solar fuels. Construction of 3D hierarchical structure is very important for efficient optoelectronic devices. It is challenging to directly fabricate 3D hierarchical structure CZTS film by a facile solution method. Herein, we present a one-step sol–gel method for fabrication of CZTS thin films with 3D hierarchical structures. For the first time, it is found that the morphologies of thin films can be adjusted between dense, porous and 3D hierarchical structures by tuning anion ratios of Cl − /Ac − in precursor solution. Further analysis suggests the formation of intermediate phases of SnO 2 nanoparticles and SnS 2 nanosheets by tuning ratios of Cl − /Ac − in precursor solution, which has important effects on the formation of different nanostructures of CZTS. This study can deepen understanding of anion’ effect on morphologies of samples using a solution method and forms a reference to prepare novel nanostructures of other materials. (paper)

Evolution of different morphologies of CdS nanoparticles by thermal decomposition of bis(thiourea)cadmium chloride in various solvents

International Nuclear Information System (INIS)

Gaur, Rama; Jeevanandam, P.

2015-01-01

CdS nanoparticles with different morphologies have been synthesized by thermal decomposition of bis(thiourea)cadmium chloride in different solvents without the use of any ligand/surfactant. CdS nanoparticles with pyramid, sponge-like and hexagonal disc-like morphologies were obtained in diphenyl ether (DPE), 1-octadecene (ODE) and ethylene glycol (EG), respectively. In addition, CdS nanoparticles with unique morphologies were obtained when the decomposition of the complex was carried out in mixed solvents (DPE–EG and ODE–EG). Extensive characterization of the CdS nanoparticles was carried out using powder X-ray diffraction, FT-IR spectroscopy, thermal analysis, field-emission scanning electron microscopy, diffuse reflectance spectroscopy and photoluminescence spectroscopy, and detailed mechanism of the formation of CdS nanoparticles with different morphologies in various solvents has been proposed

Nanocomposites based on hierarchical porous carbon fiber@vanadium nitride nanoparticles as supercapacitor electrodes.

Science.gov (United States)

Ran, Fen; Wu, Yage; Jiang, Minghuan; Tan, Yongtao; Liu, Ying; Kong, Lingbin; Kang, Long; Chen, Shaowei

2018-03-28

In this study, a hybrid electrode material for supercapacitors based on hierarchical porous carbon fiber@vanadium nitride nanoparticles is fabricated using the method of phase-separation mediated by the PAA-b-PAN-b-PAA tri-block copolymer. In the phase-separation procedure, the ionic block copolymer self-assembled on the surface of carbon nanofibers, and is used to adsorb NH 4 VO 3 . Thermal treatment at controlled temperatures under an NH 3  : N 2 atmosphere led to the formation of vanadium nitride nanoparticles that are distributed uniformly on the nanofiber surface. By changing the PAN to PAA-b-PAN-b-PAA ratio in the casting solution, a maximum specific capacitance of 240.5 F g -1 is achieved at the current density of 0.5 A g -1 with good rate capability at a capacitance retention of 72.1% at 5.0 A g -1 in an aqueous electrolyte of 6 mol L -1 KOH within the potential range of -1.10 to 0 V (rN/A = 1.5/1.0). Moreover, an asymmetric supercapacitor is assembled by using the hierarchical porous carbon fiber@vanadium nitride as the negative electrode and Ni(OH) 2 as the positive electrode. Remarkably, at the power density of 400 W kg -1 , the supercapacitor device delivers a better energy density of 39.3 W h kg -1 . It also shows excellent electrochemical stability, and thus might be used as a promising energy-storage device.

Photoelectrochemical properties of hierarchical ZnO micro-nanostructure sensitized with Sb2S3 nanoparticles

Directory of Open Access Journals (Sweden)

Zhimin GUO

2016-02-01

Full Text Available By using electrochemical deposition method, and assisted with additions of PEG-400 and EDA, well-aligned ZnO nanorods and hierarchical ZnO micro-nanostructure are fabricated directly on indium doped tin oxide coated conducting glass (ITO substrate. The shell-core Sb2S3/ZnO nanorod structure and the shell-core hierarchical Sb2S3/ZnO micro-nanostructure are prepared by chemical bath deposition method. SEM, XRD, UV-Vis and photocurrent test are used to characterize the morphology, nanostructures and their photoelectrochemical properties. The studies show that the photocurrent on the array membranes with shell-core hierarchical Sb2S3/ZnO micro-nanostructure is apparently higher than that with shell-core Sb2S3/ZnO nanorods array.

Morphology and Activity Tuning of Cu ₃ Pt/C Ordered Intermetallic Nanoparticles by Selective Electrochemical Dealloying

Energy Technology Data Exchange (ETDEWEB)

Wang, Deli; Yu, Yingchao; Zhu, Jing; Liu, Sufen; Muller, David A.; Abruña, Héctor D.

2015-02-11

Improving the catalytic activity of Pt-based bimetallic nanoparticles is a key challenge in the application of proton-exchange membrane fuel cells. Electrochemical dealloying represents a powerful approach for tuning the surface structure and morphology of these catalyst nanoparticles. We present a comprehensive study of using electrochemical dealloying methods to control the morphology of ordered Cu3Pt/C intermetallic nanoparticles, which could dramatically affect their electrocatalytic activity for the oxygen reduction reaction (ORR). Depending on the electrochemical dealloying conditions, the nanoparticles with Pt-rich core–shell or porous structures were formed. We further demonstrate that the core–shell and porous morphologies can be combined to achieve the highest ORR activity. This strategy provides new guidelines for optimizing nanoparticles synthesis and improving electrocatalytic activity.

Effect of Cu Alloying on S Poisoning of Ni Surfaces and Nanoparticle Morphologies Using Ab-Initio Thermodynamics Calculations.

Science.gov (United States)

Kim, Ji-Su; Kim, Byung-Kook; Kim, Yeong-Cheol

2015-10-01

We investigated the effect of Cu alloying on S poisoning of Ni surfaces and nanoparticle morphologies using ab-initio thermodynamics calculations. Based on the Cu segregation energy and the S adsorption energy, the surface energy and nanoparticle morphology of pure Ni, pure Cu, and NiCu alloys were evaluated as functions of the chemical potential of S and the surface orientations of (100), (110), and (111). The constructed nanoparticle morphology was varied as a function of chemical potential of S. We find that the Cu added to Ni for NiCu alloys is strongly segregated into the top surface, and increases the S tolerance of the NiCu nanoparticles.

Ultrafine Cobalt Sulfide Nanoparticles Encapsulated Hierarchical N-doped Carbon Nanotubes for High-performance Lithium Storage

International Nuclear Information System (INIS)

Li, Xiaoyan; Fu, Nianqing; Zou, Jizhao; Zeng, Xierong; Chen, Yuming; Zhou, Limin; Lu, Wei; Huang, Haitao

2017-01-01

Graphical abstract: Ultrafine cobalt sulfide nanoparticles encapsulated in hierarchical N-doped carbon nanotubes show exceptional lithium ion storage as anodes. - Abstract: Nanostructured cobalt sulfide based materials with rational design are attractive for high-performance lithium-ion batteries. In this work, we report a multistep method to synthesize ultrafine cobalt sulfide nanoparticles encapsulated in hierarchical N-doped carbon nanotubes (CoS x @HNCNTs). Co-based zeolitic imidazolate framework (ZIF-67) nanotubes are obtained from the reaction between electrospun polyacrylonitrile/cobalt acetate and 2-methylimidazole, followed by the dissolution of template. Next, a combined calcination and sulfidation process is employed to convert the ZIF-67 nanotubes to CoS x @HNCNTs. Benefited from the compositional and structural features, the as-prepared nanostructured hybrid materials deliver superior lithium storage properties with high capacity of 1200 mAh g −1 at 0.25 A g −1 . More importantly, a remarkable capacity of 1086 mAh g −1 can be maintained after 100 cycles at the current density of 0.5 A g −1 . Even at a high rate of 5 A g −1 , a reversible capacity of 592 mAh g −1 after 1600 cycles can still be achieved.

Studies on the formation of hierarchical zeolite T aggregates with well-defined morphology in different template systems

Science.gov (United States)

Yin, Xiaoyan; Chu, Naibo; Lu, Xuewei; Li, Zhongfang; Guo, Hong

2016-01-01

In this paper, the disk-like and pumpkin-like hierarchical zeolite T aggregates consisted of primary nano-grains have been hydrothermally synthesized with and without the aid of the second template. The first template is used with tetramethylammonium hydroxide (TMAOH) and the second template is used with triethanolamine (TEA) or polyving akohol (PVA). A combination of characterization techniques, including XRD, SEM, TEM and N2 adsorption-desorption to examine the crystal crystallinity, morphology and surface properties of hierarchical zeolite T aggregates. In the single-template preparation process, the two-step varying-temperature treatment has been used to improve the meso-porosity of zeolite T aggregates. In the double-template preparation process, the amounts of PVA or TEA on the crystallinity, morphology and meso-porosity of zeolite T aggregates have been studied. It has been proved that the interstitial voids between the primary grains of aggregates are the origin of additional mesopores of samples. The micro- and meso-porosities of samples prepared with and without the second template have been contrasted in detail at last. In particular, the sample synthesized with the addition of PVA presents a hierarchical pore structure with the highest Sext value of 122 m2/g and Vmeso value of 0.255 cm3/g.

Nanoparticle Decorated Ultrathin Porous Nanosheets as Hierarchical Co3O4 Nanostructures for Lithium Ion Battery Anode Materials

DEFF Research Database (Denmark)

Mujtaba, Jawayria; Sun, Hongyu; Huang, Guoyong

2016-01-01

We report a facile synthesis of a novel cobalt oxide (Co3O4) hierarchical nanostructure, in which crystalline core-amorphous shell Co3O4 nanoparticles with a bimodal size distribution are uniformly dispersed on ultrathin Co3O4 nanosheets. When tested as anode materials for lithium ion batteries...

Binary blend Nanoparticles with defined morphology

International Nuclear Information System (INIS)

Ghazy, O.A.H.

2008-01-01

nanoparticle approach relying on the mini emulsion process was presented, by which the length scale of phase separation of polymer blends is controllable down to few tens of nanometers [1-3, 10-12]. The method is based on forming a mini emulsion of the polymer solution in water and subsequently evaporating the solvent to obtain the polymer nanospheres dispersed in water. The process enables the control of the polymer particle size in the range of 50-500 nm [13-15]. The blending is done through two different approaches: either by mixing nanoparticles of pure polymers (nanoparticle blends), or by fabricating blend nanoparticles (composite particles) by starting with a mutual solution of the two polymers. Solar cells based on the mini emulsion approaches have been fabricated and their efficiency was studied [1-3], nevertheless the morphology of the polymer blends used for the fabrication was difficult to study. The difficulty is hidden in finding polymer pairs that have electronic contrast to enable the morphology study by electron microscopy

Controlled self-assembly of PbS nanoparticles into macrostar-like hierarchical structures

International Nuclear Information System (INIS)

Li, Guowei; Li, Changsheng; Tang, Hua; Cao, Kesheng; Chen, Juan

2011-01-01

Graphical abstract: The aggregation and rotation of nanoparticles to adopt parallel orientations in three dimensions was indirectly illustrated by TEM and HRTEM images. Highlights: → Macrostar-like PbS hierarchical structures was successfully synthesized by a simple hydrothermal method and mesostars were assembled from the PbS nanocube building blocks with edge lengths of about 100 nm. → Ostwald-ripening-assisted oriented attachment is believed to play a key role in the growth behavior of novel 3D structures. → Optical properties indicating few defects on the surface of the PbS structure and exhibit large blue-shifts compared to bulk PbS. -- Abstract: The synthesis of macrostar-like PbS hierarchical structures by a simple hydrothermal method at 180 o C for 24 h is proven successful with the assistance of a new surfactant called tetrabutylammonium bromide (TBAB). The as-obtained product is characterized by means of X-ray powder diffraction, field emission scanning electron microscopy, energy dispersive spectrometry, high resolution transmission electron microscopy, and selected area electron diffraction. The presence of TBAB and NaF plays an important role in the formation of PbS macrostructures. Ostwald-ripening-assisted oriented attachment is believed to play a key role in the growth behavior of novel 3D structures. As such, a possible self-assembly mechanism is proposed to explain the formation of the said structures. The present study aims to introduce new insights into understanding the formation process of such unique hierarchical superstructures.

Morphology controlled graphene-alloy nanoparticle hybrids with tunable carbon monoxide conversion to carbon dioxide.

Science.gov (United States)

Devi, M Manolata; Dolai, N; Sreehala, S; Jaques, Y M; Mishra, R S Kumar; Galvao, Douglas S; Tiwary, C S; Sharma, Sudhanshu; Biswas, Krishanu

2018-05-10

Selective oxidation of CO to CO2 using metallic or alloy nanoparticles as catalysts can solve two major problems of energy requirements and environmental pollution. Achieving 100% conversion efficiency at a lower temperature is a very important goal. This requires sustained efforts to design and develop novel supported catalysts containing alloy nanoparticles. In this regard, the decoration of nanoalloys with graphene, as a support for the catalyst, can provide a novel structure due to the synergic effect of the nanoalloys and graphene. Here, we demonstrate the effect of nano-PdPt (Palladium-Platinum) alloys having different morphologies on the catalytic efficiency for the selective oxidation of CO. Efforts were made to prepare different morphologies of PdPt alloy nanoparticles with the advantage of tuning the capping agent (PVP - polyvinyl pyrollidone) and decorating them on graphene sheets via the wet-chemical route. The catalytic activity of the G-PdPt hybrids with an urchin-like morphology has been found to be superior (higher % conversion at 135 °C lower) to that with a nanoflower morphology. The above experimental observations are further supported by molecular dynamics (MD) simulations.

Fabrication of semi-transparent superoleophobic thin film from fabrics and nanoparticle-based hierarchical structure

Directory of Open Access Journals (Sweden)

Nishizawa S.

2013-08-01

Full Text Available Superoleophobic thin films have many potential applications including fluid transfer, fluid power systems, stain resistant and antifouling materials, and microfluidics among others. Transparency is also desired with superhydrophobicity for their numerous applications; however transparency and oleophobicity are almost incompatible relationship with each other in the point of surface structure. Because oleophobicity required rougher structure at nano-micro scale than hydrophobicity, and these rough structure brings light scattering. So far, there is very few report of the compatible of transparency and superoleophobicity. In this report, we proposed the see-through type fabrics using the nanoparticle-based hierarchical structure thin film for improving both of oleophobicity and transparency. The vacant space between fibrils of fabrics has two important roles: the one is to through the light, another one is to introduce air layer to realize Cassie state of liquid droplet on thin film. To realize the low surface energy and nanoscale rough structure surface on fibrils, we used the spray method with perfluoroalkyl methacrylic copolymer (PMC, silica nano particles and volatile solvent. From the SEM image, the hierarchical structures of nanoparticle were formed uniformly on the fabrics. The transparency of thin film obtained was approximately 61% and the change of transparency between pre-coated fabrics and coated was 11%. From investigation of the surface wettability, the contact angles of oils (rapeseed oil and hexadecane and water droplet on the fabricated film were over 150 degree.

Silver nanoparticles: Influence of the temperature synthesis on the particles’ morphology

International Nuclear Information System (INIS)

Piñero, S; Camero, S; Blanco, S

2017-01-01

Silver nanoparticles have a wide range of applications in the medical field, textile and food industries. These and other applications can be found due to the relation between its size and morphology. In this study the influence of bath temperature on the morphology and size of silver nanoparticles are evaluated, which are obtained by chemical reduction of AgNO 3 using three reducing agents: sodium borohydride, ascorbic acid and sodium citrate. The evaluation carried out by the traditional UV-vis Spectrophotometric analysis and with High Resolution Transmission Electron Microscopy. The UV-vis spectrum of the silver colloids obtained by chemical reduction using three different reducing agents shows the effect of the temperature change on the growing and aggregative process. The final effect on the morphology, size and aggregation of the particles was confirmed by TEM. The result suggests a change in the growing mechanism, conducted by aggregation of atoms at 5 and 20°C degrees and aggregation of clusters at higher temperatures. Moreover in this work the main synthesis methods of nanomaterials are described. (paper)

Influence of Heat Treatment on the Morphologies of Copper Nanoparticles Based Films by a Spin Coating Method

Directory of Open Access Journals (Sweden)

Wei Liu

2017-01-01

Full Text Available We have investigated the influence of heat treatment on the morphologies of copper nanoparticles based films on glass slides by a spin coating method. The experiments show that heat treatment can modify the sizes and morphologies of copper nanoparticles based films on glass slides. We suggest that through changing the parameters of heat treatment process may be helpful to vary the scattering and absorbing intensity of copper nanoparticles when used in energy harvesting/conversion and optical devices.

Optical and morphological properties of infrared emitting functionalized silica nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Iovino, G. [Dipartimento di Fisica e Chimica, Università di Palermo, Via Archirafi 36, I-90123 Palermo (Italy); Malvindi, M.A. [Istituto Italiano di Tecnologia, Center for Bio-Molecular Nanotechnologies@Unile, Via Barsanti, Arnesano, I-73010 Lecce (Italy); Agnello, S., E-mail: simonpietro.agnello@unipa.it [Dipartimento di Fisica e Chimica, Università di Palermo, Via Archirafi 36, I-90123 Palermo (Italy); Buscarino, G.; Alessi, A. [Dipartimento di Fisica e Chimica, Università di Palermo, Via Archirafi 36, I-90123 Palermo (Italy); Pompa, P.P. [Istituto Italiano di Tecnologia, Center for Bio-Molecular Nanotechnologies@Unile, Via Barsanti, Arnesano, I-73010 Lecce (Italy); Gelardi, F.M. [Dipartimento di Fisica e Chimica, Università di Palermo, Via Archirafi 36, I-90123 Palermo (Italy)

2013-11-01

The loading process of functionalized silica nanoparticles was investigated in order to obtain nanoparticles having functional groups on their surface and Near-Infrared (NIR) emission properties. The NIR emission induced by O{sub 2} loading was studied in silica nanoparticles, produced by pyrogenic and microemulsion methods, with size ranging from 20 to 120 nm. Loading was carried out by thermal treatments in O{sub 2} atmosphere up to 400 °C and 90 bar. The effects of the thermal treatments on the NIR emission and on the structural properties were studied by luminescence and Raman techniques, whereas the morphological features were investigated by Transmission Electron Microscopy and Atomic Force Microscopy. Our data show that silica nanoparticles produced by pyrogenic technique can be loaded with O{sub 2} at lower temperature than the ones obtained by microemulsion and have a higher luminescence intensity due to the internal porosity of the latter. The treatments do not affect the nanosize of the microemulsion particles and provide NIR emitting probes of selected size. Post-processing surface functionalization of the pyrogenic nanoparticles does not affect their emission properties and provides high efficiency NIR emitters with functionalized surface. - Highlights: • Pyrogenic and microemulsion silica nanoparticles with near infrared emission. • Functionalization of nanoparticles does not change the NIR emission. • Porosity limits the emission properties of nanoparticles.

Zirconium tungstate/epoxy nanocomposites: effect of nanoparticle morphology and negative thermal expansivity.

Science.gov (United States)

Wu, Hongchao; Rogalski, Mark; Kessler, Michael R

2013-10-09

The ability to tailor the coefficient of thermal expansion (CTE) of a polymer is essential for mitigating thermal residual stress and reducing microcracks caused by CTE mismatch of different components in electronic applications. This work studies the effect of morphology and thermal expansivity of zirconium tungstate nanoparticles on the rheological, thermo-mechanical, dynamic-mechanical, and dielectric properties of ZrW2O8/epoxy nanocomposites. Three types of ZrW2O8 nanoparticles were synthesized under different hydrothermal conditions and their distinct properties were characterized, including morphology, particle size, aspect ratio, surface area, and CTE. Nanoparticles with a smaller particle size and larger surface area led to a more significant reduction in gel-time and glass transition temperature of the epoxy nanocomposites, while a higher initial viscosity and significant shear thinning behavior was found in prepolymer suspensions containing ZrW2O8 with larger particle sizes and aspect ratios. The thermo- and dynamic-mechanical properties of epoxy-based nanocomposites improved with increasing loadings of the three types of ZrW2O8 nanoparticles. In addition, the introduced ZrW2O8 nanoparticles did not negatively affect the dielectric constant or the breakdown strength of the epoxy resin, suggesting potential applications of ZrW2O8/epoxy nanocomposites in the microelectronic insulation industry.

Structural, Optical, Morphological and Microbial Studies on SnO₂ Nanoparticles Prepared by Co-Precipitation Method.

Science.gov (United States)

Arularasu, M V; Anbarasu, M; Poovaragan, S; Sundaram, R; Kanimozhi, K; Magdalane, C Maria; Kaviyarasu, K; Thema, F T; Letsholathebe, D; Mola, Genene T; Maaza, M

2018-05-01

Nanoparticles of tin oxide (SnO2) powders were prepared by co-precipitation method at 500 °C, 700 °C and 900 °C temperature. The sintered SnO2 nanoparticles, structural, optical, magnetic, morphological properties and microbial activity have been studied. XRD studies reveals that sintered powder which exhibits tetragonal crystal structure and both crystallinity as well as crystal size increase with increase in temperature. The morphological studies reveal randomly arranged grains with compact nature grain size increases with sintering temperature. The compositional analyses of SnO2 nanoparticles have been studied using X-ray photoelectron spectroscopy analysis. The optical band gap values of SnO2 nanoparticles were calculated to be about 4.3 eV in the temperature 500 °C, comparing with that of the bulk SnO2 3.78 eV, by optical absorption measurement. Room temperature M-H curve for pure SnO2 nanoparticles exhibits ferromagnetic behaviour. The tin oxide nanoparticles are acted as potential candidate material for bacterial and fungal activity.

Laser synthesized super-hydrophobic conducting carbon with broccoli-type morphology as a counter-electrode for dye sensitized solar cells

Science.gov (United States)

Gokhale, Rohan; Agarkar, Shruti; Debgupta, Joyashish; Shinde, Deodatta; Lefez, Benoit; Banerjee, Abhik; Jog, Jyoti; More, Mahendra; Hannoyer, Beatrice; Ogale, Satishchandra

2012-10-01

A laser photochemical process is introduced to realize superhydrophobic conducting carbon coatings with broccoli-type hierarchical morphology for use as a metal-free counter electrode in a dye sensitized solar cell. The process involves pulsed excimer laser irradiation of a thin layer of liquid haloaromatic organic solvent o-dichlorobenzene (DCB). The coating reflects a carbon nanoparticle-self assembled and process-controlled morphology that yields solar to electric power conversion efficiency of 5.1% as opposed to 6.2% obtained with the conventional Pt-based electrode.A laser photochemical process is introduced to realize superhydrophobic conducting carbon coatings with broccoli-type hierarchical morphology for use as a metal-free counter electrode in a dye sensitized solar cell. The process involves pulsed excimer laser irradiation of a thin layer of liquid haloaromatic organic solvent o-dichlorobenzene (DCB). The coating reflects a carbon nanoparticle-self assembled and process-controlled morphology that yields solar to electric power conversion efficiency of 5.1% as opposed to 6.2% obtained with the conventional Pt-based electrode. Electronic supplementary information (ESI) available: Materials and equipment details, solar cell fabrication protocol, electrolyte spreading time measurement details, XPS spectra, electronic study, film adhesion test detailed analysis and field emission results. See DOI: 10.1039/c2nr32082g

Morphologically tuned 3D/1D rutile TiO{sub 2} hierarchical hybrid microarchitectures engineered by one-step surfactant free hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Maria John, Maria Angelin Sinthiya [Crystal Growth and Thin Film Laboratory, Department of Physics and Nanotechnology, Faculty of Engineering and Technology, SRM University, Kattankulathur 603203, Tamil Nadu (India); Ramamurthi, K., E-mail: ramamurthi.k@ktr.srmuniv.ac.in [Crystal Growth and Thin Film Laboratory, Department of Physics and Nanotechnology, Faculty of Engineering and Technology, SRM University, Kattankulathur 603203, Tamil Nadu (India); Sethuraman, K. [School of Physics, Madurai Kamaraj University, Madurai 625021, Tamil Nadu (India); Ramesh Babu, R. [Crystal Growth and Thin Film Laboratory, School of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu (India)

2017-05-31

Highlights: • TiO{sub 2} 1D-NRs are tuned to 3D/1D-HHMs by increasing growth temperature-first report. • TiO{sub 2} seeded glass substrates are used to reduce the lattice mismatch of TiO{sub 2} HHMs. • Growth temperature influences the structural, morphological and optical properties. • Possible growth mechanism is proposed for morphological changes. - Abstract: Present investigation reports on the surfactant free hydrothermal synthesize of the morphologically tuned hierarchical hybrid rutile titanium oxide (TiO{sub 2}) microarchitectures showing three dimensional microflower structures and cook pine tree like structures on the one dimensional nanorods formed over TiO{sub 2} seed layer coated glass substrates by tuning growth temperature. TiO{sub 2} seed layer of ∼100 nm thick was coated on the glass substrates employing sol–gel spin coating method and then rutile TiO{sub 2} microarchitectures were synthesized on the TiO{sub 2} seed layer by one-step surfactant free hydrothermal method. Deposited samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, UV–vis spectroscopy and photoluminescence spectroscopy techniques. Influence of the growth temperature on the crystallinity, morphology and optical properties along with the growth mechanism to achieve hierarchical microarchitectures was investigated. Present work revealed that the structural, morphological and optical properties of the TiO{sub 2} hierarchical microarchitectures strongly depend on the growth temperature. Further we proposed a model for the cause to effect possible morphological changes of rutile TiO{sub 2} microarchitectures as a function of growth temperatures on the TiO{sub 2} seeded glass substrates.

Morphology and Structure of ZnO Nanoparticles Produced by Electrochemical Method

Directory of Open Access Journals (Sweden)

Barbara STYPUŁA

2014-04-01

Full Text Available This article presents studies of the morphology and structure of ZnO nanoparticles synthesized by the electrochemical method. Colloidal solutions of the nanoparticles are obtained by an anodic dissolution of metallic zinc in alcohol solutions of lithium chloride containing a small amount of water (5 % vol.. The parameters chosen for the synthesis are based on Zn polarization curves(obtained using the the potentiokinetic (Linear Sweep Voltammetry – LSV and the chronoamperometric method. The synthesis of zinc oxide nanoparticles is carried out in 0.05m LiCl + 5 % H2O alcohol (methanol or propanol solutions during galvanostatic polarization of Zn at 3 mA/cm2 current density. The process is performed in a two-electrode system, where both electrodes (the working anode and cathode are made of zinc. Optical properties, morphology and structure of the colloidal solutions and powders (obtained after evaporating the solvent were studied using the following spectroscopic and microscopic techniques: UltraViolet and Visible Spectroscopy (UV-VIS, Fourier Transform Infrared Spectroscopy (FTIR, Scanning Electron Microscopy (SEM and Transmission Electron Microscopy (TEM.DOI: http://dx.doi.org/10.5755/j01.ms.20.1.4417

One-Pot Synthesis of Lithium-Rich Cathode Material with Hierarchical Morphology.

Science.gov (United States)

Luo, Kun; Roberts, Matthew R; Hao, Rong; Guerrini, Niccoló; Liberti, Emanuela; Allen, Christopher S; Kirkland, Angus I; Bruce, Peter G

2016-12-14

Lithium-rich transition metal oxides, Li 1+x TM 1-x O 2 (TM, transition metal), have attracted much attention as potential candidate cathode materials for next generation lithium ion batteries because their high theoretical capacity. Here we present the synthesis of Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2 using a facile one-pot resorcinol-formaldehyde method. Structural characterization indicates that the material adopts a hierarchical porous morphology consisting of uniformly distributed small pores and disordered large pore structures. The material exhibits excellent electrochemical cycling stability and a good retention of capacity at high rates. The material has been shown to be both advantageous in terms of gravimetric and volumetric capacities over state of the art commercial cathode materials.

Electroactive nanoparticle directed assembly of functionalized graphene nanosheets into hierarchical structures with hybrid compositions for flexible supercapacitors

Science.gov (United States)

Choi, Bong Gill; Huh, Yun Suk; Hong, Won Hi; Erickson, David; Park, Ho Seok

2013-04-01

Hierarchical structures of hybrid materials with the controlled compositions have been shown to offer a breakthrough for energy storage and conversion. Here, we report the integrative assembly of chemically modified graphene (CMG) building blocks into hierarchical complex structures with the hybrid composition for high performance flexible pseudocapacitors. The formation mechanism of hierarchical CMG/Nafion/RuO2 (CMGNR) microspheres, which is triggered by the cooperative interplay during the in situ synthesis of RuO2 nanoparticles (NPs), was extensively investigated. In particular, the hierarchical CMGNR microspheres consisting of the aggregates of CMG/Nafion (CMGN) nanosheets and RuO2 NPs provided large surface area and facile ion accessibility to storage sites, while the interconnected nanosheets offered continuous electron pathways and mechanical integrity. The synergistic effect of CMGNR hybrids on the supercapacitor (SC) performance was derived from the hybrid composition of pseudocapacitive RuO2 NPs with the conductive CMGNs as well as from structural features. Consequently, the CMGNR-SCs showed a specific capacitance as high as 160 F g-1, three-fold higher than that of conventional graphene SCs, and a capacitance retention of >95% of the maximum value even after severe bending and 1000 charge-discharge tests due to the structural and compositional features.Hierarchical structures of hybrid materials with the controlled compositions have been shown to offer a breakthrough for energy storage and conversion. Here, we report the integrative assembly of chemically modified graphene (CMG) building blocks into hierarchical complex structures with the hybrid composition for high performance flexible pseudocapacitors. The formation mechanism of hierarchical CMG/Nafion/RuO2 (CMGNR) microspheres, which is triggered by the cooperative interplay during the in situ synthesis of RuO2 nanoparticles (NPs), was extensively investigated. In particular, the hierarchical CMGNR

Hierarchically porous MgCo2O4 nanochain networks: template-free synthesis and catalytic application

Science.gov (United States)

Guan, Xiangfeng; Yu, Yunlong; Li, Xiaoyan; Chen, Dagui; Luo, Peihui; Zhang, Yu; Guo, Shanxin

2018-01-01

In this work, hierarchically porous MgCo2O4 nanochain networks were successfully synthesized by a novel template-free method realized via a facile solvothermal synthesis followed by a heat treatment. The morphologies of MgCo2O4 precursor could be adjusted from nanosheets to nanobelts and finally to interwoven nanowires, depending on the volume ratio of diethylene glycol to deionized water in the solution. After calcination, the interwoven precursor nanowires were transformed to hierarchical MgCo2O4 nanochain networks with marco-/meso-porosity, which are composed of 10-20 nm nanoparticles connected one by one. Moreover, the relative formation mechanism of the MgCo2O4 nanochain networks was discussed. More importantly, when evaluated as catalytic additive for AP thermal decomposition, the MgCo2O4 nanochain networks show excellent accelerating effect. It is benefited from the unique hierarchically porous network structure and multicomponent effect, which effectively accelerates ammonia oxidation and {{{{ClO}}}4}- species dissociation. This approach opens the way to design other hierarchically porous multicomponent metal oxides.

Nanoparticle Decorated Ultrathin Porous Nanosheets as Hierarchical Co3O4 Nanostructures for Lithium Ion Battery Anode Materials

Science.gov (United States)

Mujtaba, Jawayria; Sun, Hongyu; Huang, Guoyong; Mølhave, Kristian; Liu, Yanguo; Zhao, Yanyan; Wang, Xun; Xu, Shengming; Zhu, Jing

2016-01-01

We report a facile synthesis of a novel cobalt oxide (Co3O4) hierarchical nanostructure, in which crystalline core-amorphous shell Co3O4 nanoparticles with a bimodal size distribution are uniformly dispersed on ultrathin Co3O4 nanosheets. When tested as anode materials for lithium ion batteries, the as-prepared Co3O4 hierarchical electrodes delivered high lithium storage properties comparing to the other Co3O4 nanostructures, including a high reversible capacity of 1053.1 mAhg−1 after 50 cycles at a current density of 0.2 C (1 C = 890 mAg−1), good cycling stability and rate capability. PMID:26846434

Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales.

Science.gov (United States)

Burke, Kerry B; Stapleton, Andrew J; Vaughan, Ben; Zhou, Xiaojing; Kilcoyne, A L David; Belcher, Warwick J; Dastoor, Paul C

2011-07-01

Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N'-(4-butylphenyl)-bis-N, N'-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales

Science.gov (United States)

Burke, Kerry B.; Stapleton, Andrew J.; Vaughan, Ben; Zhou, Xiaojing; Kilcoyne, A. L. David; Belcher, Warwick J.; Dastoor, Paul C.

2011-07-01

Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N'-(4-butylphenyl)-bis-N, N'-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales

International Nuclear Information System (INIS)

Burke, Kerry B; Stapleton, Andrew J; Vaughan, Ben; Zhou Xiaojing; Belcher, Warwick J; Dastoor, Paul C; Kilcoyne, A L David

2011-01-01

Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N ' -(4-butylphenyl)-bis-N, N ' -phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

Nanoparticle synthesis of zinc peroxide: structural and morphological characterization for bactericidal applications

International Nuclear Information System (INIS)

Colonia, Roberto; Martinez, Vanessa C.; Solis, Jose L.; Gomez, Monica M.

2013-01-01

Zinc peroxide (ZnO 2 ) nanoparticles were synthesized by sol-gel technique. The chemicals used for the synthesis were zinc acetate di-hydrate (Zn(CH 3 COO) 2. 2H 2 O) and hydrogen peroxide (H 2 O 2 ) at 30 % in an aqueous solution with sonication. The structure of the ZnO 2 nanoparticles was characterized by X-ray diffraction. While the morphology and the cluster size were determined using scanning and transmission electron microscopy. For a preliminary evaluation of the bactericidal properties of the ZnO 2 , the material was exposed to Staphylococcus aureus, Escherichia coli y Bacillus subtili, and the nanoparticles presented good bactericidal properties. (author)

Shape-controlled synthesis of Pt-Pd core-shell nanoparticles exhibiting polyhedral morphologies by modified polyol method

International Nuclear Information System (INIS)

Long, Nguyen Viet; Asaka, Toru; Matsubara, Takashi; Nogami, Masayuki

2011-01-01

Pt-Pd core-shell nanoparticles were synthesized by a simple synthetic method. First, Pt nanoparticles were synthesized in a controlled manner via the reduction of chloroplantinic acid hexahydrate in ethylene glycol (EG) at 160 deg. C in the presence of silver nitrate and the stabilization of polyvinylpyrrolidon. AgNO 3 used acts as a structure-modifying agent to the morphology of the Pt nanoparticles. These Pt nanoparticles function as the seeds for the successive reduction of sodium tetrachloropalladate (II) hydrate in EG under stirring for 15 min at 160 deg. C in order to synthesize Pt-Pd core-shell nanoparticles. To characterize the as-prepared Pt-Pd nanoparticles, transmission electron microscopy (TEM) and high-resolution TEM are used. The high-resolution elemental mappings were carried out using the combination of scanning TEM and X-ray energy-dispersive spectroscopy. The results also demonstrate the homogeneous nucleation and growth of the Pd metal shell on the definite Pt core. The synthesized Pt-Pd core-shell nanoparticles exhibit a sharp and polyhedral morphology. The epitaxial growth of the controlled Pd shells on the Pt cores via a polyol method was observed. It is suggested that Frank-van der Merwe and Stranski-Krastanov growth modes coexisted in the nucleation and growth of Pt-Pd core-shell nanoparticles.

Influence of CdS nanoparticles grain morphology on laser-induced absorption

Science.gov (United States)

Ebothé, Jean; Michel, Jean; Kityk, I. V.; Lakshminarayana, G.; Yanchuk, O. M.; Marchuk, O. V.

2018-06-01

Using external illumination of a 7 nanosecond (ns) doubled frequency Nd: YAG laser emitting at λ = 532 nm with frequency repetition 10 Hz it was established a possibility of significant changes of the absorption at the probing wavelength 1150 nm of continuous wave (cw) He-Ne laser for the CdS nanoparticles embedded into the PVA polymer matrix. The effect is observed only during the two beam laser coherent treatment and this effect is a consequence of interference of two coherent beams. It is shown a principal role of the grain morphology in the efficiency of the process, which is more important than the nanoparticle sizes. The photoinduced absorption is manifested in the space distribution of the probing laser beam. The principal role of the grain interfaces between the nanoparticle interfaces and the surrounding polymer matrix is shown. The effect is almost independent of the nanoparticle sizes. It may be used for laser operation by nanocomposites.

Prediction of the effects of size and morphology on the structure of water around hematite nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Spagnoli, D.; Gilbert, B.; Waychunas, G.A.; Banfield, J. F.

2009-05-15

Compared with macroscopic surfaces, the structure of water around nanoparticles is difficult to probe directly. We used molecular dynamics simulations to investigate the effects of particle size and morphology on the time-averaged structure and the dynamics of water molecules around two sizes of hematite ({alpha}-Fe{sub 2}O{sub 3}) nanoparticles. Interrogation of the simulations via atomic density maps, radial distribution functions and bound water residence times provide insight into the relationships between particle size and morphology and the behavior of interfacial water. Both 1.6 and 2.7 nm particles are predicted to cause the formation of ordered water regions close to the nanoparticle surface, but the extent of localization and ordering, the connectivity between regions of bound water, and the rates of molecular exchange between inner and outer regions are all affected by particle size and morphology. These findings are anticipated to be relevant to understanding the rates of interfacial processes involving water exchange and the transport of aqueous ions to surface sites.

Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales

Energy Technology Data Exchange (ETDEWEB)

Burke, Kerry B; Stapleton, Andrew J; Vaughan, Ben; Zhou Xiaojing; Belcher, Warwick J; Dastoor, Paul C [Centre for Organic Electronics, University of Newcastle, Callaghan, NSW 2308 (Australia); Kilcoyne, A L David, E-mail: Paul.Dastoor@newcastle.edu.au [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2011-07-01

Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N{sup '}-(4-butylphenyl)-bis-N, N{sup '}-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

Morphology-controlled hydrothermal synthesis of MnCO3 hierarchical superstructures with Schiff base as stabilizer

International Nuclear Information System (INIS)

Hu, He; Xu, Jie-yan; Yang, Hong; Liang, Jie; Yang, Shiping; Wu, Huixia

2011-01-01

Graphical abstract: MnCO3 microcrystals with hierarchical superstructures were synthesized by using the CO2 in atmosphere as carbonate ions source and Schiff base as shape guiding-agent in water/ethanol system under hydrothermal condition. Highlights: → The most interesting in this work is the use of the greenhouse gases CO 2 in atmosphere as carbonate ions source to precipitate with Mn 2+ for producing MnCO 3 crystals. → This work is the first report related to the small organic molecule Schiff base as shape guiding-agent to produce different MnCO 3 hierarchical superstructures. → We are controllable synthesis of the MnCO 3 hierarchical superstructures such as chrysanthemum, straw-bundle, dumbbell and sphere-like microcrystals. → The as-prepared MnCO 3 could be used precursor to fabricate the Mn 2 O 3 hierarchical superstructures after thermal decomposition at high temperature. -- Abstract: MnCO 3 with hierarchical superstructures such as chrysanthemum, straw-bundle, dumbbell and sphere-like were synthesized in water/ethanol system under environment-friendly hydrothermal condition. In the synthesis process, the CO 2 in atmosphere was used as the source of carbonate ions and Schiff base was used as shape guiding-agent. The different superstructures of MnCO 3 could be obtained by controlling the hydrothermal temperature, the molar ratio of manganous ions to the Schiff base, or the volume ratio of water to ethanol. A tentative growth mechanism for the generation of MnCO 3 superstructures was proposed based on the rod-dumbbell-sphere model. Furthermore, the MnCO 3 as precursor could be further successfully transferred to Mn 2 O 3 microstructure after heating in the atmosphere at 500 o C, and the morphology of the Mn 2 O 3 was directly determined by that of the MnCO 3 precursor.

Porous silicon nanoparticles for target drag delivery: structure and morphology

International Nuclear Information System (INIS)

Spivak, Yu M; Belorus, A O; Somov, P A; Bespalova, K A; Moshnikov, V A; Tulenin, S S

2015-01-01

Nanoparticles of porous silicon were obtained by electrochemical anodic etching. Morphology and structure of the particles was investigated by means dynamic light scattering and scanning electron microscopy. The influence of technological conditions of preparation on geometrical parameters of the porous silicon particles (particle size distribution, pore shape and size, the specific surface area of the porous silicon) is discussed. (paper)

Tunable fabrication of hierarchical hybrids via the incorporation of poly(dopamine) functional interlayer

Energy Technology Data Exchange (ETDEWEB)

Xu, Ting; Zhao, Xin; Zhang, Junxian; Dong, Jie; Zhang, Qinghua, E-mail: qhzhang@dhu.edu.cn

2016-04-30

Highlights: • PS/PDA with well-defined core/shell structures was prepared in aqueous solution. • Au NPs were coated on PS/PDA by in-situ reduction and self-assembly approach. • PS/PDA/Au had homogeneous and dense Au coatings with different shape. • Hierarchical spheres exhibited a well-defined core/shell structure maintaining the spherical morphology. - Abstract: Two kinds of ternary hybrids were prepared by anchoring different shapes and loadings of Au nanoparticles (NPs) on poly(dopamine) (PDA) functionalized polystyrene (PS) microspheres with two different strategies, i.e., in situ reduction and self-assembly approach. PDA coatings were firstly introduced to functionalize the hydrophobic PS surface with sufficient amino and hydroxyl groups, which enhanced the interaction between Au NPs and the polymer spheres. Thus, Au NPs could be easily immobilized onto the surface of the PDA/PS microspheres, and the hierarchical composite microspheres exhibited a well-defined core/shell structure without sacrificing the spherical PS morphology. PS/PDA/Au-R and PS/PDA/Au-A microspheres fabricated by in situ reduction and self-assembly approach showed different distinct Au nano-shell morphology with the corresponding optical, catalytic and electrochemical properties. Field emission scanning electron microscopy and transmission electronic microscopy verified these hierarchical structures with the ultrathin PDA film incorporating between the inner PS core and the outer Au NPs shell. X-ray diffraction and X-ray photoelectron spectroscopy confirmed the presence of PDA and Au layer on the surface of the composite particles. These green and facile methods with mild experimental conditions can extend to fabricate other polymer or inorganic substrates coated by various noble metals.

Phase- and shape-controlled hydrothermal synthesis of CdS nanoparticles, and oriented attachment growth of its hierarchical architectures

Science.gov (United States)

Cao, Yali; Hu, Pengfei; Jia, Dianzeng

2013-01-01

Hydrothermal strategies were successfully used to control the phases and morphologies of CdS nanocrystals. In the absence of an external direction-controlling process, the hexagonal and cubic phase well-defined leaf- and flower-like CdS nanocrystals were controlled obtained via adjusting the reaction duration or the concentration of surfactant. Oriented attachment growth modes were suggested for the formation of CdS superstructures, which was clarified through the tracing of temporal evolution of CdS nanoparticles. The CdS superstructures were structured by primary building nanoparticles, and held excellent visible emission with a peak in the green regions. This strategy is very helpful for studying the phase and morphology controlled fabrication of sulfides nanocrystals.

Morphology modification of gold nanoparticles from nanoshell to C-shape: Improved surface enhanced Raman scattering

International Nuclear Information System (INIS)

Xing, Ting-Yang; Zhu, Jian; Li, Jian-Jun; Zhao, Jun-Wu

2016-01-01

Morphology modification of nanostructures is of great interest, because it can be used to fabricate nanostructures which are hard to be done using other methods. Different from traditional lithographic technique which is slow and expensive, morphology modification is easy, cheap, and reproducible. In this paper, modification of the optical and morphological properties of a hollow gold nanoshell (HGNS) is achieved by using H 2 O 2 as an oxidizer. The reshaping of these nanostructures has been demonstrated as a consequence of an oxidation process in which HGNSs are dissolved by H 2 O 2 under the acidic conditions provided by HCl. We investigate the oxidation process by a transmission electron microscope and propose a reshaping model involving four different shapes (HGNS, HGNS with hole, gold nanoring, and C-shaped gold nanoparticle) which are corresponding to the oxidation products of HGNSs at different pH values. Besides, the surface enhanced Raman scattering (SERS) activity of each oxidation product has been evaluated by using rhodamine 6G as the Raman active probe. It has been observed that the C-shaped gold nanoparticles which are corresponding to the oxidation products at the minimum pH value have the highest SERS activity and this result can also be interpreted by discrete-dipole approximation simulations. We demonstrate that the morphology modification of HGNSs becomes possible in a controlled manner using wet chemistry and can be used in preparation of gold nanoparticles such as HGNS with hole, gold nanoring, and C-shaped gold nanoparticle with large SERS activity. These nanostructures must have potential use in many plasmonic areas, including sensing, catalysis, and biomedicine.

Morphology modification of gold nanoparticles from nanoshell to C-shape: Improved surface enhanced Raman scattering

Energy Technology Data Exchange (ETDEWEB)

Xing, Ting-Yang; Zhu, Jian; Li, Jian-Jun; Zhao, Jun-Wu, E-mail: nanoptzhao@163.com [The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi' an Jiaotong University, Xi' an 710049 (China)

2016-06-28

Morphology modification of nanostructures is of great interest, because it can be used to fabricate nanostructures which are hard to be done using other methods. Different from traditional lithographic technique which is slow and expensive, morphology modification is easy, cheap, and reproducible. In this paper, modification of the optical and morphological properties of a hollow gold nanoshell (HGNS) is achieved by using H{sub 2}O{sub 2} as an oxidizer. The reshaping of these nanostructures has been demonstrated as a consequence of an oxidation process in which HGNSs are dissolved by H{sub 2}O{sub 2} under the acidic conditions provided by HCl. We investigate the oxidation process by a transmission electron microscope and propose a reshaping model involving four different shapes (HGNS, HGNS with hole, gold nanoring, and C-shaped gold nanoparticle) which are corresponding to the oxidation products of HGNSs at different pH values. Besides, the surface enhanced Raman scattering (SERS) activity of each oxidation product has been evaluated by using rhodamine 6G as the Raman active probe. It has been observed that the C-shaped gold nanoparticles which are corresponding to the oxidation products at the minimum pH value have the highest SERS activity and this result can also be interpreted by discrete-dipole approximation simulations. We demonstrate that the morphology modification of HGNSs becomes possible in a controlled manner using wet chemistry and can be used in preparation of gold nanoparticles such as HGNS with hole, gold nanoring, and C-shaped gold nanoparticle with large SERS activity. These nanostructures must have potential use in many plasmonic areas, including sensing, catalysis, and biomedicine.

Polymer brushes on nanoparticles: their positioning in and influence on block copolymer morphology.

Science.gov (United States)

Kim, Bumjoon

2007-03-01

Polymers brushes grafted to the nanoparticle surface enable the precise positioning of particles within a block copolymer matrix by determining the compatibility of nanoparticles within a polymeric matrix and modifying the interfacial properties between polymers and inorganic nanoparticle. Short thiol terminated polystyrene (PS-SH), poly(2-vinylpyridine) (P2VP-SH) and PS-r-P2VP with the molecular weight (Mn) of 3 kg/mol were used to control the location of Au nanoparticles over PS-b-P2VP diblock copolymer template. We will discuss further the approach of varying the areal chain density (σ) of PS-SH brushes on the PS coated particles, which utilizes the preferential wetting of one block of a copolymer (P2VP) on the Au substrate. Such favorable interaction provides the strong binding of Au particles to the PS/P2VP interface as σ of PS chains on the Au particle decreases. We find that at σ above a certain value, the nanoparticles are segregated to the center of the PS domains while below this value they are segregated to the interface. The transition σ for PS-SH chains (Mn = 3.4 kg/mol) is 1.3 chains/nm^2 but unexpectedly scales as Mn-0.55 as Mn is varied from 1.5 to 13 kg/mol. In addition, we will discuss changes in block copolymer morphology that occur as the nanoparticle volume fraction (φ) is increased for nanoparticles that segregate to the domain center as well as those that segregate to the interface, the latter behaving as nanoparticle surfactants. Small φ of such surfactants added to lamellar diblock copolymers lead initially to a decrease in lamellar thickness, a consequence of decreasing interfacial tension, up to a critical value of φ beyond which the block copolymer adopts a bicontinuous morphology. I thank my collaborators G. H. Fredrickson, J. Bang, C. J. Hawker, and E. J. Kramer as well as funding by the MRL as UCSB from the NSF-MRSEC-Program Award DMR05-20418.

Hetero- and homogeneous three-dimensional hierarchical tungsten oxide nanostructures by hot-wire chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Houweling, Z.S., E-mail: Silvester.Houweling@asml.com [Utrecht University, Debye Institute for Nanomaterials Science, Nanophotonics—Physics of Devices, Princetonlaan 4, 3584 CB Utrecht (Netherlands); Harks, P.-P.R.M.L.; Kuang, Y.; Werf, C.H.M. van der [Utrecht University, Debye Institute for Nanomaterials Science, Nanophotonics—Physics of Devices, Princetonlaan 4, 3584 CB Utrecht (Netherlands); Geus, J.W. [Utrecht University, Inorganic Chemistry and Catalysis, Padualaan 8, 3584 CH Utrecht (Netherlands); Schropp, R.E.I. [Utrecht University, Debye Institute for Nanomaterials Science, Nanophotonics—Physics of Devices, Princetonlaan 4, 3584 CB Utrecht (Netherlands)

2015-01-30

We present the synthesis of three-dimensional tungsten oxide (WO{sub 3−x}) nanostructures, called nanocacti, using hot-wire chemical vapor deposition. The growth of the nanocacti is controlled through a succession of oxidation, reduction and re-oxidation processes. By using only a resistively heated W filament, a flow of ambient air and hydrogen at subatmospheric pressure, and a substrate heated to about 700 °C, branched nanostructures are deposited. We report three varieties of simple synthesis approaches to obtain hierarchical homo- and heterogeneous nanocacti. Furthermore, by using catalyst nanoparticles site-selection for the growth is demonstrated. The atomic, morphological and crystallographic compositions of the nanocacti are determined using a combination of electron microscopy techniques, energy-dispersive X-ray spectroscopy and electron diffraction. - Highlights: • Continuous upscalable hot-wire CVD of 3D hierarchical nanocacti • Controllable deposition of homo- and heterogeneous WO{sub 3−x}/WO{sub 3−y} nanocacti • Introduction of three synthesis routes comprising oxidation, reduction and re-oxidation processes • Growth of periodic arrays of hetero- and homogeneous hierarchical 3D nanocacti.

Morphology evolution of PS-b-PDMS block copolymer and its hierarchical directed self-assembly on block copolymer templates

DEFF Research Database (Denmark)

Rasappa, Sozaraj; Schulte, Lars; Borah, Dipu

2018-01-01

Cylinder-forming polystyrene-block-polydimethylsiloxane (PS-b-PDMS, 27.2k-b-11.7k, SD39) block copolymer having a total molecular weight of 39 kg mol−1 was exploited to achieve in-plane morphologies of lines, dots and antidots. Brush-free self-assembly of the SD39 on silicon substrates was invest...... substrates provides a simplified method for surface nanopatterning, templated growth of nanomaterials and nanofabrication....... the pattern into the underlying substrate. Directed self-assembly and hierarchical directed self-assembly on block copolymer templates for confinement of dots was successfully demonstrated. The strategy for achieving multiple morphologies using one BCP by mere choice of the annealing solvents on unmodified...

Solvothermal synthesis of hierarchical TiO{sub 2} nanostructures with tunable morphology and enhanced photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Fan, Zhenghua [School of Physics and Materials Science, Anhui University, Hefei 230601 (China); Meng, Fanming, E-mail: mrmeng@ahu.edu.cn [School of Physics and Materials Science, Anhui University, Hefei 230601 (China); Key laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Zhang, Miao [School of Physics and Materials Science, Anhui University, Hefei 230601 (China); Wu, Zhenyu [College of Chemistry & Chemical Engineering, Anhui University, Hefei 230601 (China); Sun, Zhaoqi; Li, Aixia [School of Physics and Materials Science, Anhui University, Hefei 230601 (China)

2016-01-01

Graphical abstract: - Highlights: • Hierarchical anatase TiO{sub 2} nanostructures with enhanced photocatalytic activity are synthesized by solvothermal method. • A mechanism for enhanced photocatalytic activity of chrysanthemum-like hierarchical TiO{sub 2} nanostructures is proposed. • A possible formation mechanism is suggested to explain the transformation from rose-like to chrysanthemum-like, and to sea-urchin-like. - Abstract: This paper presents controllable growth and photocatalytic activity of TiO{sub 2} hierarchical nanostructures by solvothermal method at different temperatures. It is revealed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) that the morphology of TiO{sub 2} can be effectively controlled as rose-like, chrysanthemum-like and sea-urchin-like only changing solvothermal temperature. BET surface area analysis confirms the presence of a mesoporous network in all the nanostructures, and shows high surface area at relatively high temperature. The photocatalytic activities of the photocatalysts are evaluated by the photodegradation of RhB under UV light irradiation. The TiO{sub 2} samples exhibit high activity on the photodegradation of RhB, which is higher than that of the commercial P25. The enhancement in photocatalytic performance can be attributed to the synergetic effect of the surface area, crystallinity, band gap and crystalline size.

Biomedical application of hierarchically built structures based on metal oxides

Science.gov (United States)

Korovin, M. S.; Fomenko, A. N.

2017-12-01

Nowadays, the use of hierarchically built structures in biology and medicine arouses much interest. The aim of this work is to review and summarize the available literature data about hierarchically organized structures in biomedical application. Nanoparticles can serve as an example of such structures. Medicine holds a special place among various application methods of similar systems. Special attention is paid to inorganic nanoparticles based on different metal oxides and hydroxides, such as iron, zinc, copper, and aluminum. Our investigations show that low-dimensional nanostructures based on aluminum oxides and hydroxides have an inhibitory effect on tumor cells and possess an antimicrobial activity. At the same time, it is obvious that the large-scale use of nanoparticles by humans needs to thoroughly study their properties. Special attention should be paid to the study of nanoparticle interaction with living biological objects. The numerous data show that there is no clear understanding of interaction mechanisms between nanoparticles and various cell types.

Structural, morphological, and optical properties of tin(IV) oxide nanoparticles synthesized using Camellia sinensis extract: a green approach

Science.gov (United States)

Selvakumari, J. Celina; Ahila, M.; Malligavathy, M.; Padiyan, D. Pathinettam

2017-09-01

Tin oxide (SnO2) nanoparticles were cost-effectively synthesized using nontoxic chemicals and green tea ( Camellia sinensis) extract via a green synthesis method. The structural properties of the obtained nanoparticles were studied using X-ray diffraction, which indicated that the crystallite size was less than 20 nm. The particle size and morphology of the nanoparticles were analyzed using scanning electron microscopy and transmission electron microscopy. The morphological analysis revealed agglomerated spherical nanoparticles with sizes varying from 5 to 30 nm. The optical properties of the nanoparticles' band gap were characterized using diffuse reflectance spectroscopy. The band gap was found to decrease with increasing annealing temperature. The O vacancy defects were analyzed using photoluminescence spectroscopy. The increase in the crystallite size, decreasing band gap, and the increasing intensities of the UV and visible emission peaks indicated that the green-synthesized SnO2 may play future important roles in catalysis and optoelectronic devices.

Morphological quantification of hierarchical geomaterials by X-ray nano-CT bridges the gap from nano to micro length scales

KAUST Repository

Brisard, S.

2012-01-30

Morphological quantification of the complex structure of hierarchical geomaterials is of great relevance for Earth science and environmental engineering, among others. To date, methods that quantify the 3D morphology on length scales ranging from a few tens of nanometers to several hun-dred nanometers have had limited success. We demonstrate, for the first time, that it is possible to go beyond visualization and to extract quantitative morphological information from X-ray images in the aforementioned length scales. As examples, two different hierarchical geomaterials exhibiting complex porous structures ranging from nanometer to macroscopic scale are studied: a flocculated clay water suspension and two hydrated cement pastes. We show that from a single projection image it is possible to perform a direct computation of the ultra-small angle-scattering spectra. The predictions matched very well the experimental data obtained by the best ultra-small angle-scattering experimental setups as observed for the cement paste. In this context, we demonstrate that the structure of flocculated clay suspension exhibit two well-distinct regimes of aggregation, a dense mass fractal aggregation at short distance and a more open structure at large distance, which can be generated by a 3D reaction limited cluster-cluster aggregation process. For the first time, a high-resolution 3D image of fibrillar cement paste cluster was obtained from limited angle nanotomography.

The SL-assisted synthesis of hierarchical ZnO nanostructures and their enhanced photocatalytic activity

International Nuclear Information System (INIS)

Miao Tingting; Guo Yuanru; Pan Qingjiang

2013-01-01

Hierarchical ZnO nanoparticle-bar, nanomesh-lamina, and quasi-nanosphere structures have been successfully synthesized by the precipitation method with assistance of sodium lignosulphonate (SL). It is shown that the obtained ZnO nanomaterials are well crystallized and possess hexagonal wurtzite structure after calcination. Morphologies of ZnO with particle sizes ranging from 50 to 200 nm can be fabricated by tuning the SL amount in our synthetic route. Plenty of pores have been observed both in nanoparticle-bar and nanomesh-lamina ZnO. This may provide scaffold microenvironments to enhance their photocatalytic activity. It is evident that the synthesized ZnO exhibits good photocatalytic activity of degrading methylene blue, even under a very low-power UV illumination, which allows for the treatment of wastewater containing organic pollutants in an effective way. Among our synthesized nanomaterials, the nanomesh-lamina ZnO has the highest photodegradation efficiency, achieving nearly 100 % degradation only within 1.5 h (UV irradiation power of 12 W). As these ZnO nanomaterials are simply synthesized using SL which is a pulp industry by-product and their intrinsic hierarchical nanostructures show outstanding photocatalytic behavior, we expect the present controllable, environment-friendly, and cost-effective approach to be applied in the synthesis of small-sized ZnO materials.

The SL-assisted synthesis of hierarchical ZnO nanostructures and their enhanced photocatalytic activity

Science.gov (United States)

Miao, Ting-Ting; Guo, Yuan-Ru; Pan, Qing-Jiang

2013-06-01

Hierarchical ZnO nanoparticle-bar, nanomesh-lamina, and quasi-nanosphere structures have been successfully synthesized by the precipitation method with assistance of sodium lignosulphonate (SL). It is shown that the obtained ZnO nanomaterials are well crystallized and possess hexagonal wurtzite structure after calcination. Morphologies of ZnO with particle sizes ranging from 50 to 200 nm can be fabricated by tuning the SL amount in our synthetic route. Plenty of pores have been observed both in nanoparticle-bar and nanomesh-lamina ZnO. This may provide scaffold microenvironments to enhance their photocatalytic activity. It is evident that the synthesized ZnO exhibits good photocatalytic activity of degrading methylene blue, even under a very low-power UV illumination, which allows for the treatment of wastewater containing organic pollutants in an effective way. Among our synthesized nanomaterials, the nanomesh-lamina ZnO has the highest photodegradation efficiency, achieving nearly 100 % degradation only within 1.5 h (UV irradiation power of 12 W). As these ZnO nanomaterials are simply synthesized using SL which is a pulp industry by-product and their intrinsic hierarchical nanostructures show outstanding photocatalytic behavior, we expect the present controllable, environment-friendly, and cost-effective approach to be applied in the synthesis of small-sized ZnO materials.

Magnetic properties and morphology of manganese ferrite nanoparticles in glasses

International Nuclear Information System (INIS)

Edelman, I; Ivanova, O; Ivantsov, I; Velikanov, D; Petrakovskaja, E; Artemenko, A; Curély, J; Kliava, J; Zaikovskiy, V; Stepanov, S

2011-01-01

Static magnetization (SM), magnetic circular dichroism (MCD) and electron magnetic resonance (EMR) studies are reported of borate glasses 22.5 K 2 O-22.5 Al 2 O 3 -55 B 2 O 3 co-doped with iron and manganese oxides. In as-prepared glasses the paramagnetic ions usually are in diluted state; however, if the ratio of the iron and manganese oxides in the charge is 3/2, magnetic nanoparticles are found already in as-prepared glass. After additional thermal treatment all glasses show magnetic behaviour, MCD and EMR due to the presence of magnetic nanoparticles with characteristics close to those of manganese ferrite. By computer simulating the EMR spectra at variable temperatures, their morphological characteristics are deduced: relatively broad size and shape distribution with average diameter of ca. 3-4 nm. The characteristic temperature-dependent shift of the apparent resonance field is explained by a strong temperature dependence of the magnetocrystalline anisotropy in the nanoparticles. The potassium-alumina-borate glasses containing magnetic nanoparticles represent a novel class of materials: t ransparent magnets . Indeed, they remain transparent in a part of visible and near infrared spectral range while showing magnetic and magneto-optical properties characteristic of magnetically ordered materials.

Visualisation of morphological interactionof diamond and silver nanoparticles with Salmonella enteritidis and Listeria Monocytogenes

DEFF Research Database (Denmark)

Sawosz, Ewa; Chwalibog, André; Mitura, Katarzyna

2011-01-01

Currently, medicine intensively searches for methods to transport drugs to a target (sick) point within the body. The objective of the present investigation was to evaluate morphological characteristics of the assembles of silver or diamond nanoparticles with Salmonella Enteritidis (G-) or Listeria...... monocytogenes (G+), to reveal possibilities of constructing nanoparticle-bacteria vehicles. Diamond nanoparticles (nano-D) were produced by the detonation method. Hydrocolloids of silver nanoparticles (nano-Ag) were produced by electric non-explosive patented method. Hydrocolloids of nanoparticles (200 microl...

Dissolution, agglomerate morphology, and stability limits of protein-coated silver nanoparticles.

Science.gov (United States)

Martin, Matthew N; Allen, Andrew J; MacCuspie, Robert I; Hackley, Vincent A

2014-09-30

Little is understood regarding the impact that molecular coatings have on nanoparticle dissolution kinetics and agglomerate formation in a dilute nanoparticle dispersion. Dissolution and agglomeration processes compete in removing isolated nanoparticles from the dispersion, making quantitative time-dependent measurements of the mechanisms of nanoparticle loss particularly challenging. In this article, we present in situ ultra-small-angle X-ray scattering (USAXS) results, simultaneously quantifying dissolution, agglomeration, and stability limits of silver nanoparticles (AgNPs) coated with bovine serum albumin (BSA) protein. When the BSA corona is disrupted, we find that the loss of silver from the nanoparticle core is well matched by a second-order kinetic rate reaction, arising from the oxidative dissolution of silver. Dissolution and agglomeration are quantified, and morphological transitions throughout the process are qualified. By probing the BSA-AgNP suspension around its stability limits, we provide insight into the destabilization mechanism by which individual particles rapidly dissolve as a whole rather than undergo slow dissolution from the aqueous interface inward, once the BSA layer is breached. Because USAXS rapidly measures over the entire nanometer to micrometer size range during the dissolution process, many insights are also gained into the stabilization of NPs by protein and its ability to protect the labile metal core from the solution environment by prohibiting the diffusion of reactive species. This approach can be extended to a wide variety of coating molecules and reactive metal nanoparticle systems to carefully survey their stability limits, revealing the likely mechanisms of coating breakdown and ensuing reactions.

Synthesis and characterization of polyhedral and quasi-sphere non-polyhedral Pt nanoparticles: effects of their various surface morphologies and sizes on electrocatalytic activity for fuel cell applications

International Nuclear Information System (INIS)

Long, Nguyen Viet; Ohtaki, Michitaka; Hien, Tong Duy; Jalem, Randy; Nogami, Masayuki

2011-01-01

In this article, polyhedral and non-polyhedral Pt nanoparticles were prepared by modified polyol method using AgNO 3 as a good structure-modifying agent. Their TEM and HRTEM images showed the particle size in the range of 8–16 nm for both the above cases. The structures and properties of the surfaces of Pt nanoparticles were investigated through cyclic voltammetry in dilute perchloric acid (HClO 4 ) electrolyte solution. A comparison of the electrocatalytic property in methanol electrooxidation was made. Here, the effects of polyhedral and non-polyhedral morphologies on their catalytic properties were studied. The results revealed that the special catalytic activity of quasi-sphere non-polyhedral Pt nanoparticles is higher than that of polyhedral Pt nanoparticles. In addition, Pt nanoparticles of un-sharp and quasi-sphere morphologies exhibit the tolerance to poisoning species better than that of Pt nanoparticles of sharp and polyhedral morphologies due to the various morphologies of the catalyst surfaces in the chronoamperometric plots. Therefore, these experimental evidences showed the morphology-dependent catalytic property according to the various morphologies and complexity of their catalyst surfaces.

Structure and morphology of platinum nanoparticles with critical new issues of low- and high-index facets

DEFF Research Database (Denmark)

Nguyen, Viet-Long; Ohtaki, Michitaka; Van Nong, Ngo

2012-01-01

In this paper, Pt nanoparticles were successfully prepared by modified polyol method using silver nitrate as an effective structure-modifying agent. The characterization of Pt nanoparticles was investigated by using UV-Vis-NIR spectroscopy, transmission electron microscopy (TEM) and high resolution...... (HR) TEM, and x-ray diffraction (XRD). The method of selected area electron diffraction (SEAD) was used to study the structure of Pt nanoparticles. The results showed that the as-prepared Pt nanoparticles exhibiting the complexity of surface structure and morphology could be used as efficient...... catalysts for polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs)....

Facile synthesis of hierarchical CoMn2O4 microspheres with porous and micro-/nanostructural morphology as anode electrodes for lithium-ion batteries

Science.gov (United States)

Li, Yana; Hou, Xianhua; Li, Yajie; Ru, Qiang; Wang, Shaofeng; Hu, Shejun; Lam, Kwok-ho

2017-09-01

Hierarchical CoMn2O4 microspheres assembled by nanoparticles have been successfully synthesized by a facile hydrothermal method and a subsequent annealing treatment. XRD detection indicate the crystal structure. SEM and TEM results reveal the 3-dimensional porous and micro-/nanostructural microsphere assembled by nanoparticles with a size of 20-100 nm. The CoMn2O4 electrode show initial specific discharge capacity of approximately 1546 mAh/g at the current rates 100 mA/g with a coulombic efficiency of 66.7% and remarkable specific capacities (1029-485 mAh/g) at various current rates (100-2800 mA/g). [Figure not available: see fulltext.

New insight in magnetic saturation behavior of nickel hierarchical structures

Science.gov (United States)

Ma, Ji; Zhang, Jianxing; Liu, Chunting; Chen, Kezheng

2017-09-01

It is unanimously accepted that non-ferromagnetic inclusions in a ferromagnetic system will lower down total saturation magnetization in unit of emu/g. In this study, ;lattice strain; was found to be another key factor to have critical impact on magnetic saturation behavior of the system. The lattice strain determined assembling patterns of primary nanoparticles in hierarchical structures and was intimately related with the formation process of these architectures. Therefore, flower-necklace-like and cauliflower-like nickel hierarchical structures were used as prototype systems to evidence the relationship between assembling patterns of primary nanoparticles and magnetic saturation behaviors of these architectures. It was found that the influence of lattice strain on saturation magnetization outperformed that of non-ferromagnetic inclusions in these hierarchical structures. This will enable new insights into fundamental understanding of related magnetic effects.

Hierarchical machining materials and their performance

DEFF Research Database (Denmark)

Sidorenko, Daria; Loginov, Pavel; Levashov, Evgeny

2016-01-01

as nanoparticles in the binder, or polycrystalline, aggregate-like reinforcements, also at several scale levels). Such materials can ensure better productivity, efficiency, and lower costs of drilling, cutting, grinding, and other technological processes. This article reviews the main groups of hierarchical...

Structure and Morphology Effects on the Optical Properties of Bimetallic Nanoparticle Films Laser Deposited on a Glass Substrate

Directory of Open Access Journals (Sweden)

A. O. Kucherik

2017-01-01

Full Text Available Moving nanosecond laser system is used for laser-assisted thermodiffusion deposition of metallic nanoparticles from water-based colloidal solutions. The results obtained for both gold and silver nanoparticles show that film morphology strongly depends on laser scanning speed and the number of passages. We show, furthermore, the possibility of producing bimetallic Au:Ag thin films by laser irradiation of the mixed solutions. As a result of several laser scans, granular nanometric films are found to grow with a well-controlled composition, thickness, and morphology. By changing laser scanning parameters, film morphology can be varied from island structures to quasi-periodic arrays. The optical properties of the deposited structures are found to depend on the film composition, thickness, and mean separation between the particles. The transparency spectra of the deposited films are shown to be defined by their morphology.

Mo-doped V2O5 hierarchical nanorod/nanoparticle core/shell porous microspheres with improved performance for cathode of lithium-ion battery

Science.gov (United States)

Yu, Haolin; Zeng, Jianyun; Hao, Wen; Zhou, Peng; Wen, Xiaogang

2018-05-01

Mo-doped V2O5 hierarchical nanorod/nanoparticle core/shell porous microspheres (MVHPMs) were prepared via a simple hydrothermal approach using ammonium metavanadate and ammonium molybdate as precursors followed by a thermal annealing process. The samples were characterized by XRD, SEM, TEM, EDS, and XPS carefully; it confirmed that porous microspheres with uniform Mo doping in the V2O5 matrix were obtained, and it contains an inner core self-assembled with 1D nanorods and outer shell consisting of nanoparticles. A plausible growth mechanism of Mo-doped V2O5 (Mo-V2O5) porous microspheres is suggested. The unique microstructure made the Mo-V2O5 hierarchical microspheres a good cathode material for Li-ion battery. The results indicate the synthesized Mo-V2O5 hierarchical microspheres exhibit well-improved electrochemical performance compared to the undoped samples. It delivers a high initial reversible capacity of 282 mAh g-1 at 0.2 C, 208 mAh g-1 at 2 C, and 111 mAh g-1 at 10 C, and it also exhibits good cycling stabilities; a capacity of 144 mAh g-1 is obtained after 200 cycles at 6 C with a capacity retention of > 82%, which is much high than that of pure V2O5 (95 mAh g-1 with a capacity retention of 72%). [Figure not available: see fulltext.

Clay nanoparticles effects on performance and morphology of poly(vinylidene fluoride membranes

Directory of Open Access Journals (Sweden)

A. C. D. Morihama

2014-03-01

Full Text Available In this study, a comparison between neat poly(vinylidene fluoride (PVDF membrane and composite (PVDF-Nanoclay and PVDF-PVP-Nanoclay membranes is presented. All membranes were synthesized by the phase inversion process, using 18% PVDF, n-methylpyrrolidone as solvent and water as the non-solvent. Demineralized water cross-flow permeation tests were conducted to evaluate the membranes performance. Scanning electron microscopy (SEM images of the membranes surface and cross-section and water contact angle measurements were used to estimate additives effects on membranes morphology. The results indicate that dopant addition affected membrane permeate flux and morphology. The 4% nanoclay composite membrane resulted in the highest ultrapure water permeability (0.9130 m³.m-2.h-1.MPa-1, lower hydraulic resistance (3.27´10+12.m-1, lower contact angle (87.1º and highest surface porosity (0.95%. Furthermore, it was verified that the membrane surface porosity increased with increasing clay nanoparticles concentrations. It was observed that the morphology of the membranes with clay nanoparticle addition is characterized by a thin surface layer, with macro-pores, a thin bottom layer, which has a sponge-like structure with micro-pores and a thick intermediate layer, with finger-like pores and macro-pores. It was also verified that the introduction of PVP promotes a denser morphology compared with membranes without it. Based on the SEM surface and cross-sectional images and permeability tests, it became evident that the internal pore morphology plays an important role in membrane performance, because the higher the frequency and extent of the finger-like pores in the intermediate layer the higher is the membrane permeability. These preliminary results indicated that the use of nanoclay as an additive for membrane casting is a promising procedure for improving membrane performance for water and wastewater treatment.

Shape-controlled synthesis of NIR absorbing branched gold nanoparticles and morphology stabilization with alkanethiols

International Nuclear Information System (INIS)

Van de Broek, B; Frederix, F; Bonroy, K; Jans, H; Jans, K; Borghs, G; Maes, G

2011-01-01

Gold nanoparticles are ideal candidates for clinical applications if their plasmon absorption band is situated in the near infrared region (NIR) of the electromagnetic spectrum. Various parameters, including the nanoparticle shape, strongly influence the position of this absorption band. The aim of this study is to produce stabilized NIR absorbing branched gold nanoparticles with potential for biomedical applications. Hereto, the synthesis procedure for branched gold nanoparticles is optimized varying the different synthesis parameters. By subsequent electroless gold plating the plasmon absorption band is shifted to 747.2 nm. The intrinsic unstable nature of the nanoparticles' morphology can be clearly observed by a spectral shift and limits their use in real applications. However, in this article we show how the stabilization of the branched structure can be successfully achieved by exchanging the initial capping agent for different alkanethiols and disulfides. Furthermore, when using alkanethiols/disulfides with poly(ethylene oxide) units incorporated, an increased stability of the gold nanoparticles is achieved in high salt concentrations up to 1 M and in a cell culture medium. These achievements open a plethora of opportunities for these stabilized branched gold nanoparticles in nanomedicine.

Morphological Investigation and Fractal Properties of Realgar Nanoparticles

Directory of Open Access Journals (Sweden)

Amir Lashgari

2015-01-01

Full Text Available Some arsenic compounds can show extraordinary polymorphism. Realgar (As4S4 is among several minerals with various crystal forms and is one of the most important sources of arsenic for pharmaceutical use. Currently, realgar is used as an arsenic source in many industries, such as weaponry, publishing, textiles, cosmetics, and health products. In this paper, we used and reported new methods for the purification, nanonization, and structural morphological investigations of As4S4 by using planetary ball mills process for nanonization of the compound. The product was characterized using X-ray powder diffraction analysis, Fourier transform infrared spectrometry spectra, and field emission scanning electron microscope (FESEM imaging. We investigated the morphological properties of FESEM-imaged realgar nanoparticles by an image-processing technique that calculates fractal dimensions using values on a computer with MATLAB software. We applied the Statistical Package for the Social Sciences software for statistics data extracted from the FESEM image and obtained the statistics results of the fractal dimension and histogram plot for the FESEM image.

Investigation on structural, surface morphological and dielectric properties of Zn-doped SnO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Sagadevan, Suresh [Department of Physics, AMET University, Chennai (India); Podder, Jiban, E-mail: sureshsagadevan@gmail.com [Department of Chemical and Biological Engineering, University of Saskatchewan (Canada)

2016-03-15

Zinc doped Tin oxide (SnO{sub 2}) nanoparticles were prepared by co-precipitation method. The average crystallite size of pure and Zn-doped SnO{sub 2} nanoparticles was calculated from the X-ray diffraction (XRD) pattern. The FT-IR spectrum indicated the strong presence of SnO{sub 2} nanoparticles. The morphology and the particle size were studied using the scanning electron microscope (SEM) and transmission electron microscope (TEM). The particle size of the Zn-doped SnO{sub 2} nanoparticles was also analyzed, using the Dynamic Light Scattering (DLS) experiment. The optical properties were studied by the UV-Visible absorption spectrum. The dielectric properties of Zn-doped SnO{sub 2} nanoparticles were studied at different frequencies and temperatures. The ac conductivity of Zn-doped SnO{sub 2} nanoparticles was also studied. (author)

Microstructure, morphology and magnetic properties of Ni nanoparticles synthesized by hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Bouremana, A. [LPM, Faculty of Sciences, USTHB, BP 32, El-Alia, Bab Ezzouar, Algiers (Algeria); Guittoum, A., E-mail: aguittoum@gmail.com [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399, Alger-Gare, Algiers (Algeria); Hemmous, M. [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399, Alger-Gare, Algiers (Algeria); Martínez-Blanco, D. [SCTs, University of Oviedo, EPM, 33600 Mieres (Spain); Gorria, Pedro [Department of Physics & IUTA, EPI, University of Oviedo, 33203 Gijón (Spain); Blanco, J.A. [Department of Physics, University of Oviedo, Calvo Sotelo St., 33007 Oviedo (Spain); Benrekaa, N. [LPM, Faculty of Sciences, USTHB, BP 32, El-Alia, Bab Ezzouar, Algiers (Algeria)

2015-06-15

Powder samples containing high purity nickel nanoparticles (NPs) were prepared by hydrothermal method from Ni(II) chloride hexahydrate (NiCl{sub 2}·6H{sub 2}O) under the presence of sodium hydroxide (NaOH) with different concentrations between 5 and 25 mol/L. The synthesis of the NPs occurs through chemical reduction at relatively low temperature (140 °C). The Ni NPs have a face-centred cubic (fcc) crystal structure with a lattice parameter value close to that of pure Ni (a = 3.52 Å). The average crystallite size determined from x-ray diffraction is around 20 nm, except for the sample synthesized under the highest NaOH concentration (25 mol/L), which has the largest average size (>30 nm). The powder morphology at the sub-micrometre length scale looks like agglomerates of Ni-NPs that drastically changes their shape depending on the NaOH concentration, from flower (5 mol/L) to a dendritic-like (25 mol/L). All the samples are ferromagnetic at room temperature with saturation magnetization values between 50 and 52emu/g, and a coercive field that increases with the NaOH concentration from around 135 (5 mol/L) up to 180Oe (25 mol/L). - Highlights: • Pure Nickel nanoparticles have been synthesized by a chemical reaction process. • Different morphologies were observed with the change of NaOH concentration. • The coercive field increases with increasing the NaOH concentration and depends on the shape of nanoparticles.

Phase diagrams and morphological evolution in wrapping of rod-shaped elastic nanoparticles by cell membrane: A two-dimensional study

Science.gov (United States)

Yi, Xin; Gao, Huajian

2014-06-01

A fundamental understanding of cell-nanomaterial interaction is essential for biomedical diagnostics, therapeutics, and nanotoxicity. Here, we perform a theoretical analysis to investigate the phase diagram and morphological evolution of an elastic rod-shaped nanoparticle wrapped by a lipid membrane in two dimensions. We show that there exist five possible wrapping phases based on the stability of full wrapping, partial wrapping, and no wrapping states. The wrapping phases depend on the shape and size of the particle, adhesion energy, membrane tension, and bending rigidity ratio between the particle and membrane. While symmetric morphologies are observed in the early and late stages of wrapping, in between a soft rod-shaped nanoparticle undergoes a dramatic symmetry breaking morphological change while stiff and rigid nanoparticles experience a sharp reorientation. These results are of interest to the study of a range of phenomena including viral budding, exocytosis, as well as endocytosis or phagocytosis of elastic particles into cells.

Silver nanoparticles in blends of polyethylene and a superabsorbent polymer: morphology and silver ion release

Czech Academy of Sciences Publication Activity Database

Stará, Hana; Starý, Z.; Münstedt, H.

2011-01-01

Roč. 296, č. 5 (2011), s. 423-427 ISSN 1438-7492 Institutional research plan: CEZ:AV0Z40500505 Keywords : electron microscopy * morphology * nanoparticles Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.986, year: 2011

Influence of hydrocolloidal silver nanoparticles on gastrointestinal microflora and morphology of enterocytes of quails

DEFF Research Database (Denmark)

Sawosz, Ewa; Binek, Marian; Grodzik, Marta

2007-01-01

The objective of the present study was to examine the effects of hydrocolloidal silver nanoparticles (Ag-nano) on microbial profile of caecum and morphology of enterocytes in duodenum of Japanese quail, as a model animal for poultry. Quails (Coturnix coturnix japonica) (10 d old) were randomly...... killed and samples of duodenum and caeca microflora were collected. This initial investigation demonstrated that silver nanoparticles did not influence emphatically microflora of quail caecum; however, water containing 25 mg/kg of Ag-nano significantly increased the population of lactic acid bacteria...

Gold nanoparticles-immobilized, hierarchically ordered, porous TiO2 nanotubes for biosensing of glutathione

Directory of Open Access Journals (Sweden)

Sheen Mers SV

2015-10-01

Full Text Available SV Sheen Mers,1,2 Elumalai Thambuswamy Deva Kumar,1 V Ganesh1,2 1Electrodics and Electrocatalysis (EEC Division, Council of Scientific and Industrial Research–Central Electrochemical Research Institute (CSIR–CECRI, Karaikudi, Tamil Nadu, India; 2Academy of Scientific and Innovative Research (AcSIR, New Delhi, India Abstract: Glutathione (GSH is vital for several functions of our human body such as neutralization of free radicals and reactive oxygen compounds, maintaining the active forms of vitamin C and E, regulation of nitric oxide cycle, iron metabolism, etc. It is also an endogenous antioxidant in most of the biological reactions. Given the importance of GSH, a simple strategy is proposed in this work to develop a biosensor for quantitative detection of GSH. This particular biosensor comprises of gold nanoparticles (Au NPs-immobilized, hierarchically ordered titanium dioxide (TiO2 porous nanotubes. Hexagonally arranged, honeycomb-like nanoporous tubular TiO2 electrodes are prepared by using a simple electrochemical anodization process by applying a constant potential of 30 V for 24 hours using ethylene glycol consisting of ammonium fluoride as an electrolytic medium. Structural morphology and crystalline nature of such TiO2 nanotubes are analyzed using field emission scanning electron microscope (FESEM and X-ray diffraction (XRD. Interestingly, nanocomposites of TiO2 with Au NPs is prepared in an effort to alter the intrinsic properties of TiO2, especially tuning of its band gap. Au NPs are prepared by a well-known Brust and Schiffrin method and are immobilized onto TiO2 electrodes which act as a perfect electrochemical sensing platform for GSH detection. Structural characterization and analysis of these modified electrodes are performed using FESEM, XRD, and UV-visible spectroscopic studies. GSH binding events on Au NPs-immobilized porous TiO2 electrodes are monitored by electrochemical techniques, namely, cyclic voltammetry (CV and

Structural, morphological and dielectric studies of zirconium substituted CoFe2O4 nanoparticles

Directory of Open Access Journals (Sweden)

S. Anand

2017-12-01

Full Text Available In this work, the influence of zirconium substitution in cubic spinel nanocrystalline CoFe2O4 on the structural, morphological and dielectric properties are reported. Zirconium substituted cobalt ferrite Co1-xZrxFe2O4 (x = 0.7 nanoparticles were synthesized by sol-gel route. The structural and morphological investigations using powder X-ray diffraction and high resolution scanning electron microscope (HRSEM analysis are reported. Scherrer plot, Williamson–Hall analysis and Size-strain plot method were used to calculate the crystallite size and lattice strain of the samples. High purity chemical composition of the sample was confirmed by energy dispersive X-ray analysis. The atoms vibration modes of as synthesized nanoparticles were recorded using Fourier transform infrared (FTIR spectrometer in the range of 4000–400 cm-1. The temperature-dependent dielectric properties of zirconium substituted cobalt ferrite nanoparticles were also carried out. Relative dielectric permittivity, loss tangent and AC conductivity were measured in the frequency range 50 Hz to 5 MHz at temperatures between 323 K and 473 K. The dielectric constant and dielectric loss values of the sample decreased with increasing in the frequency of the applied signal.

Hierarchical structures and phase nucleation and growth during pressure-induced crystallization of polypropylene containing dispersion of nanoclay: The impact on physical and mechanical properties

International Nuclear Information System (INIS)

Misra, R.D.K.; Yuan, Q.; Chen, J.; Yang, Y.

2010-01-01

The objective of this study is to describe the evolution of structure and phases during pressure-induced crystallization of polymers containing dispersion of nanoparticles, in the pressure range of 0.1-200 MPa. The model material for nanoparticles is nanoclay and the model polymer is polypropylene, which can potentially form several crystalline phases. While the phase selection in polypropylene is dictated by pressure and temperature, however, the introduction of nanoparticles alters the nucleation and growth of phases via nanoparticle interface driven evolution. To delineate and separate the effects of applied crystallization pressure from nanoparticle effects, a relative comparison is made between neat polypropylene and polypropylene containing dispersion of nanoclay under similar experimental conditions. The significant finding is that nanoclay interacts with the host polypropylene in a manner such that it alters the structural morphology of α- and γ-crystals of polypropylene. Furthermore, nanoclay promotes the formation of γ-phase at ambient pressure suggesting its role as structure and morphology director in the stabilization of the less accessible γ-phase, and with the possibility of epitaxial growth that enhances toughness. The equilibrium melting point measurements point to thermodynamic interaction between nanoclay and polypropylene, which is supported by the change in glass transition temperature. Thus, the two components, nanoclay and pressure, together provide a unique opportunity to tune hierarchical structures and phase evolution, which has significant implication on physico-chemical and mechanical properties.

Phase formation, morphology and magnetic properties of MgFe{sub 2}O{sub 4} nanoparticles synthesized by hydrothermal technique

Energy Technology Data Exchange (ETDEWEB)

Nonkumwong, Jeeranan [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Ananta, Supon [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Jantaratana, Pongsakorn [Department of Physics, Faculty of Science, Kasetsart University, Bangkok 11900 (Thailand); Phumying, Santi; Maensiri, Santi [Advanced Materials Physics Laboratory (Amp.), School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Srisombat, Laongnuan, E-mail: slaongnuan@yahoo.com [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

2015-05-01

In the present work, the processing conditions for obtaining monodispersed magnesium ferrite (MgFe{sub 2}O{sub 4}) nanoparticles with the desired morphology and relatively high saturation magnetization via hydrothermal technique were developed. For the first time, the effects of base type and reaction conditions (i.e. temperature and time) on phase formation, morphology and magnetic properties of the obtained products were determined by using a combination of XRD, TEM/EDX and VSM techniques. It is seen that the saturation magnetization of the particles can be increased by employing lower reaction temperature and/or shorter reaction time, while narrow size distribution of the particles can be maintained. In addition, it was found that pure phase of superparamagnetic MgFe{sub 2}O{sub 4} nanoparticles with the smallest size of about 65 nm was obtained by using CH{sub 3}COONa as a base at 180 °C for 14 h. - Highlights: • Preparation of MgFe{sub 2}O{sub 4} nanoparticles by hydrothermal method. • Effects of base and reaction conditions on formation and morphology MgFe{sub 2}O{sub 4} particles. • Producing the 65 nm MgFe{sub 2}O{sub 4} nanoparticles with superparamagnetic property.

Cellular Internalization and Biocompatibility of Periodic Mesoporous Organosilica Nanoparticles with Tunable Morphologies: From Nanospheres to Nanowires

KAUST Repository

Fatieiev, Yevhen; Croissant, Jonas G.; Alamoudi, Kholod; Khashab, Niveen M.

2017-01-01

This work describes the sol-gel syntheses of para-substituted phenylene-bridged periodic mesoporous organosilica (PMO) nanoparticles (NPs) with tunable morphologies ranging from nanowires to nanospheres. The findings show the key role

Novel hybrid coatings with controlled wettability by composite nanoparticle aggregation

Energy Technology Data Exchange (ETDEWEB)

Hritcu, Doina, E-mail: dhritcu@ch.tuiasi.ro; Dodi, Gianina; Iordache, Mirabela L.; Draganescu, Dan; Sava, Elena; Popa, Marcel I.

2016-11-30

Highlights: • Magnetite-grafted chitosan composite nanoparticles were synthesized. • The particles are able to assemble under the influence of a silane derivative. • Thin films containing composites, chitosan and hydrolyzed silane were optimized. • The novel hybrid coatings show hierarchical roughness and high wetting angle. - Abstract: The aim of this study is to evaluate novel hybrid materials as potential candidates for producing coatings with hierarchical roughness and controlled wetting behaviour. Magnetite (Fe{sub 3}O{sub 4}) nanoparticles obtained by co-precipitation were embedded in matrices synthesized by radical graft co-polymerization of butyl acrylate (BA), butyl methacrylate (BMA), hexyl acrylate (HA) or styrene (ST) with ethylene glycol di-methacrylate (EGDMA) onto previously modified chitosan bearing surface vinyl groups. The resulting composite particles were characterized regarding their average size, composition and magnetic properties. Hybrid thin films containing suspension of composite particles in ethanol and pre-hydrolysed hexadecyltrimethoxysilane (HDTS) as a coupling/crosslinking agent were deposited by spin coating or spraying. The films were cured by heating and subsequently characterized regarding their morphology (scanning electron microscopy), contact angle with water and adhesion to substrate (scratch test). The structure-property relationship is discussed.

Hierarchical assembly of inorganic nanostructure building blocks to octahedral superstructures-a true template-free self-assembly

International Nuclear Information System (INIS)

Kuchibhatla, Satyanarayana V N T; Karakoti, Ajay S; Seal, Sudipta

2007-01-01

A room temperature, template-free, wet chemical synthesis of ceria nanoparticles and their long term ageing characteristics are reported. High resolution transmission electron microscopy and UV-visible spectroscopy techniques are used to observe the variation in size, structure and oxidation state, respectively as a function of time. The morphology variation and the hierarchical assembly (octahedral superstructure) of nanostructures are imputed to the inherent structural aspects of cerium oxide. It is hypothesized that the 3-5 nm individual building blocks will undergo an intra-agglomerate re-orientation to attain the low energy configuration. This communication also emphasizes the need for long term ageing studies of nanomaterials in various solvents for multiple functionalities

Colloidal strategies for controlling the morphology, composition, and crystal structure of inorganic nanoparticles

Science.gov (United States)

Hodges, James M.

Emerging applications and fundamental studies require nanomaterials with increasingly sophisticated architectures that have precise composition, morphology, and crystal structure. Colloidal nanochemistry has emerged as one of the most effective methods for generating high quality, monodisperse nanoparticles with diverse structural features and highly complex geometries. These wet-chemical approaches offer an array of synthetic levers that can be used to tailor nanoparticles for targeted applications, and deliver solution-dispersible solids that are easily integrated onto device architectures. Additionally, colloidal nanoparticles can be used as building blocks for constructing periodic superlattices and multicomponent hybrid nanoparticles, which offer unique properties that can support next-generation technologies. As the applications for colloidal nanoparticles continue to expand, the architectural and compositional requirements for these materials are becoming increasingly rigid. Conventional colloidal methods are effective for generating diverse nanoparticle systems, but rely on complex nucleation and growth processes, which are often poorly understood and difficult to control in dynamic reaction environments. For these reasons, there are a number of high profile nanoparticle targets that remain out of reach. Accordingly, new approaches are needed that can circumvent these synthetic bottlenecks and narrow the growing disconnect between nano-design and synthetic capability. In this dissertation, I present several colloidal strategies for engineering synthetically challenging nanomaterials using multistep reaction sequences that, in many ways, parallel the total-synthesis framework that organic chemists use to access complex molecules. A variety of approaches are discussed, including nanoscale ion exchange transformations and seeded-growth protocol for constructing multicomponent hybrid nanoparticles. First, I demonstrate that solution-mediated anion and cation

An ordered array of hierarchical spheres for surface-enhanced Raman scattering detection of traces of pesticide

Science.gov (United States)

Hu, Xiaoye; Zheng, Peng; Meng, Guowen; Huang, Qing; Zhu, Chuhong; Han, Fangming; Huang, Zhulin; Li, Zhongbo; Wang, Zhaoming; Wu, Nianqiang

2016-09-01

An ordered array of hierarchically-structured core-nanosphere@space-layer@shell-nanoparticles has been fabricated for surface-enhanced Raman scattering (SERS) detection. To fabricate this hierarchically-structured chip, a long-range ordered array of Au/Ag-nanospheres is first patterned in the nano-bowls on the planar surface of ordered nanoporous anodic titanium oxide template. A ultra-thin alumina middle space-layer is then conformally coated on the Au/Ag-nanospheres, and Ag-nanoparticles are finally deposited on the surface of the alumina space-layer to form an ordered array of Au/Ag-nanosphere@Al2O3-layer@Ag-nanoparticles. Finite-difference time-domain simulation shows that SERS hot spots are created between the neighboring Ag-nanoparticles. The ordered array of hierarchical nanostructures is used as the SERS-substrate for a trial detection of methyl parathion (a pesticide) in water and a limit of detection of 1 nM is reached, indicating its promising potential in rapid monitoring of organic pollutants in aquatic environment.

Morphology control of MnO2 nanoparticles: Effect of P123 polymer in ethanol-water system

Directory of Open Access Journals (Sweden)

Chen Li

2017-01-01

Full Text Available A series of MnO2 nanoparticles were synthesized by two-step reaction in the ethanol-water system with urea as reducing agent. During the novel routine, P123 polymer plays a crucial role in controlling the morphology. Then, characterization and systematic investigations of the samples by transmission electron microscopy and scanning electron microscopy confirmed that the morphology of MnO2 nanoparticles changed as the raw materials ratio changed. Finally, X-ray diffraction and X-ray photoelectron spectroscopy were employed to confirm the crystal structure and the exact components. These results indicated the particles showed a rod-like shape without P123 and changed into sheet-like shape after the addition of P123. Therefore, this idea could be developed for the controllable synthesis of other metal oxide-based nanomaterials.

Biofabrication of morphology improved cadmium sulfide nanoparticles using Shewanella oneidensis bacterial cells and ionic liquid: For toxicity against brain cancer cell lines.

Science.gov (United States)

Wang, Li; Chen, Siyuan; Ding, Yiming; Zhu, Qiang; Zhang, Nijia; Yu, Shuqing

2018-01-01

The present work determines the anticancer activity of bio-mediated synthesized cadmium sulfide nanoparticles using the ionic liquid and bacterial cells (Shewanella oneidensis). Bacterial cells have been exposed to be important resources that hold huge potential as ecofriendly, cost-effective, evading toxic of dangerous chemicals and the alternative of conventional physiochemical synthesis. The Shewanella oneidensis is an important kind of metal reducing bacterium, known as its special anaerobic respiratory and sulfate reducing capacity. The crystalline nature, phase purity and surface morphology of biosynthesized cadmium sulfide nanoparticles were analyzed by Fourier transform infrared spectroscopy, X-ray diffraction, Field emission scanning electron microscopy, Energy dispersive spectroscopy and Transmission electron microscopy. The use of imidazolium based ionic liquids as soft templating agent for controlling self-assembly and crystal growth direction of metal sulfide nanoparticles has also advanced as an important method. The microscopic techniques showed that the nanoparticles are designed on the nano form and have an excellent spherical morphology, due to the self-assembled mechanism of ionic liquid assistance. The antitumor efficiency of the cadmium sulfide nanoparticles was investigated against brain cancer cell lines using rat glioma cell lines. The effectively improved nano-crystalline and morphological structure of CdS nanoparticles in the presence of IL exhibit excellent cytotoxicity and dispersion ability on the cell shape is completely spread out showing a nice toxic environment against cancer cells. The cytotoxicity effect of cadmium sulfide nanoparticles was discussed with a diagrammatic representation. Copyright © 2017. Published by Elsevier B.V.

Synthesis of hierarchical mesoporous lithium nickel cobalt manganese oxide spheres with high rate capability for lithium-ion batteries

Science.gov (United States)

Tong, Wei; Huang, Yudai; Cai, Yanjun; Guo, Yong; Wang, Xingchao; Jia, Dianzeng; Sun, Zhipeng; Pang, Weikong; Guo, Zaiping; Zong, Jun

2018-01-01

Hierarchical mesoporous LiNi1/3Co1/3Mn1/3O2 spheres have been synthesized by urea-assisted solvothermal method with adding Triton X-100. The structure and morphology of the as-prepared materials were analyzed by X-ray diffraction and electron microscope. The results show that the as-prepared samples can be indexed as hexagonal layered structure with hierarchical architecture, and the possible formation mechanism is speculated. When evaluated as cathode material, the hierarchical mesoporous LiNi1/3Co1/3Mn1/3O2 spheres show good electrochemical properties with high initial discharge capacity of 129.9 mAh g-1, and remain the discharge capacity of 95.5 mAh g-1 after 160 cycles at 10C. The excellent electrochemical performance of the as-prepared sample can be attributed to its stable hierarchical mesoporous framework in conjunction with large specific surface, low cation mixing and small particle size. They not only provide a large number of reaction sites for surface or interface reaction, but also shorten the diffusion length of Li+ ions. Meanwhile, the mesoporous spheres composed of nanoparticles can contribute to high rate ability and buffer volume changes during charge/discharge process.

Hierarchical architectures TiO2: Pollen-inducted synthesis, remarkable crystalline-phase stability, tunable size, and reused photo-catalysis

International Nuclear Information System (INIS)

Dou, Lingling; Gao, Lishuang; Yang, Xiaohui; Song, Xiuqin

2012-01-01

Highlights: ► The synthetic method is much milder and simpler than that of conventional methods. ► The obtained hierarchical TiO 2 shows three interesting hierarchical morphology. ► The products have tunable crystal phase structures. ► The pure phase of anatase can be retained after being annealed at 900 °C. ► The product exhibits higher and reused photo-catalytic activity. - Abstract: TiO 2 with hierarchical architectures, tunable crystalline phase and thermal stability is successfully fabricated on a large scale through a facile hydrolysis process of TiCl 4 combining with inducing of pollen. The structure of the as-prepared TiO 2 is characterized by X-ray diffraction, Raman spectroscopy, infrared spectra, and scanning electron microscopy. The experimental results indicate that different phases (anatase, rutile or mixed crystallite) of TiO 2 can be synthesized by controlling the experimental conditions. The pure phase of rutile or anatase can be obtained at 100 °C, while the pure phase of anatase can be retained after being annealed at 900 °C. The hierarchical structures TiO 2 are constitute through self-assembly of nanoparticles or nanorods TiO 2 , which exhibit high and reused photo-catalytic properties for degradation of methylene blue.

Controlling the morphology and properties of solvothermal synthesized Cu2ZnSnS4 nanoparticles by solvent type

International Nuclear Information System (INIS)

Bahramzadeh, Saeid; Abdizadeh, Hossein; Golobostanfard, Mohammad Reza

2015-01-01

Highlights: • CZTS nanoparticles are fabricated by solvothermal method with different solvents. • Different morphologies are achieved by EDA, TETA, EG, and OA solvents. • Property and chelating ability of the solvents have a key role on nanoparticles formation. • TETA and OA are strongly recommended for solar cell applications. - Abstract: The copper–zinc–tin sulfide Cu 2 ZnSnS 4 (CZTS) semiconductors are recently considered as one of the favorable materials for application as absorber layers in solar cells due to their appropriate direct band gap energy and high optical absorption coefficient. In this study, the effect of solvent type on properties of solvothermal synthesized CZTS nanoparticles has been investigated. Ethylenediamine (EDA), triethylenetetramine (TETA), ethylene glycol (EG), and oleic acid (OA) have been used as the solvent. X-ray diffraction technique and Raman spectroscopy confirmed the formation of crystalline CZTS nanoparticles with kesterite crystal structure in these solvents with the exception of EDA, which forms wurtzite crystal structure. Morphological characterizations show that several distinct morphologies including spherical (70–160 nm), nanoplates (∼45 nm thickness and more than 1 μm length), peculiar flower-like particles (with diameter of ∼0.4–1.5 μm), truncated hexagonal disks, irregular particles, and hexagonal microdisks are obtained by varying the solvent type. Optical studies revealed broad absorption of the CZTS particles in the visible region. Compared with other solvents, OA synthesized CZTS particles show higher absorption in the visible region. However, CZTS nanoparticles synthesized by TETA solvent show the most appropriate properties for application as an absorber materials in solar cells due to high crystallinity, low impurity phases, suitable size, and proper band gap energy

DNA nanoparticles with core-shell morphology.

Science.gov (United States)

Chandran, Preethi L; Dimitriadis, Emilios K; Lisziewicz, Julianna; Speransky, Vlad; Horkay, Ferenc

2014-10-14

Mannobiose-modified polyethylenimines (PEI) are used in gene therapy to generate nanoparticles of DNA that can be targeted to the antigen-presenting cells of the immune system. We report that the sugar modification alters the DNA organization within the nanoparticles from homogenous to shell-like packing. The depth-dependent packing of DNA within the nanoparticles was probed using AFM nano-indentation. Unmodified PEI-DNA nanoparticles display linear elastic properties and depth-independent mechanics, characteristic of homogenous materials. Mannobiose-modified nanoparticles, however, showed distinct force regimes that were dependent on indentation depth, with 'buckling'-like response that is reproducible and not due to particle failure. By comparison with theoretical studies of spherical shell mechanics, the structure of mannobiosylated particles was deduced to be a thin shell with wall thickness in the order of few nanometers, and a fluid-filled core. The shell-core structure is also consistent with observations of nanoparticle denting in altered solution conditions, with measurements of nanoparticle water content from AFM images, and with images of DNA distribution in Transmission Electron Microscopy.

Determination of Morphological Parameters of Supported Gold Nanoparticles: Comparison of AFM Combined with Optical Spectroscopy and Theoretical Modeling versus TEM

Directory of Open Access Journals (Sweden)

Frank Hubenthal

2012-07-01

Full Text Available The morphology of small gold particles prepared by Volmer–Weber growth on sapphire substrates have been investigated by two different characterization techniques. First, by non-extensive atomic force microscopy (AFM in combination with optical spectroscopy and modeling of the optical properties using a theoretical model, recently developed in our group. Second, by extensive transmission electron microscopy (TEM. Comparing the results obtained with both techniques demonstrate that for small gold nanoparticles within the quasistatic limit, the morphological properties can be precisely determined by an appropriate theoretical modeling of the optical properties in combination with simple AFM measurements. The apparent mean axial ratio of the nanoparticles, i.e., the axial ratio that corresponds to the center frequency of the ensemble plasmon resonance, is obtained easily from the extinction spectrum. The mean size is determined by the nanoparticle number density and the amount of deposited material, measured by AFM and a quartz micro balance, respectively. To extract the most probable axial ratio of the nanoparticle ensemble, i.e., the axial ratio that corresponds to the most probable nanoparticle size in the ensemble, we apply the new theoretical model, which allows to extract the functional dependence of the nanoparticle shape on its size. The morphological parameters obtained with this procedure will be afterwards compared to extensive TEM measurements. The results obtained with both techniques yield excellent agreement. For example, the lateral dimensions of the nanoparticles after deposition of 15.2 × 1015 atoms/cm2 of gold has been compared. While a mean lateral diameter of (13 ± 2 nm has been extracted from AFM, optical spectroscopy and modeling, a value of (12 ± 2 nm is derived from TEM. The consistency of the results demonstrate the precision of our new model. Moreover, since our theoretical model allows to extract the functional

Fine tuning of size and morphology of magnetite nanoparticles synthesized by microemulsion

Science.gov (United States)

Singh, Pinki; Upadhyay, Chandan

2018-05-01

The synthesis parameters crucially affect the physical and chemical parameters of nanoparticles. Magnetite (Fe3O4) nanoparticles were synthesized using microemulsion method. This method does not require high temperature synthesis, nitrogen environment and/or pH regulation during synthesis process. We are presenting here a systematic study on role of different associated parameters of microemulsion synthesis method on the formation of Fe3O4 nanoparticles. From X-ray Diffraction and Transmission Electron Micoscopy data analysis the size of synthesized particles were observed to be <10 nm. The critical concentration of ferrous-ferric solution to obtain particles in single phase has been found to be ≤0.09 M and ≤0.184 M, respectively. The variation of molar concentration (0.01 M ≤x≤ 0.1 M) of CTAB leads to formation of Fe3O4 nano-scale particles of distinct morphologies e.g. nano-cubes, pentagons and spheres. The number of ferrous and ferric ions involved in the formation decides the size of the nanoparticles. The single crystallographic phase is obtained in reaction temperature range of 65° C

Hierarchically Structured Electrospun Fibers

Directory of Open Access Journals (Sweden)

Nicole E. Zander

2013-01-01

Full Text Available Traditional electrospun nanofibers have a myriad of applications ranging from scaffolds for tissue engineering to components of biosensors and energy harvesting devices. The generally smooth one-dimensional structure of the fibers has stood as a limitation to several interesting novel applications. Control of fiber diameter, porosity and collector geometry will be briefly discussed, as will more traditional methods for controlling fiber morphology and fiber mat architecture. The remainder of the review will focus on new techniques to prepare hierarchically structured fibers. Fibers with hierarchical primary structures—including helical, buckled, and beads-on-a-string fibers, as well as fibers with secondary structures, such as nanopores, nanopillars, nanorods, and internally structured fibers and their applications—will be discussed. These new materials with helical/buckled morphology are expected to possess unique optical and mechanical properties with possible applications for negative refractive index materials, highly stretchable/high-tensile-strength materials, and components in microelectromechanical devices. Core-shell type fibers enable a much wider variety of materials to be electrospun and are expected to be widely applied in the sensing, drug delivery/controlled release fields, and in the encapsulation of live cells for biological applications. Materials with a hierarchical secondary structure are expected to provide new superhydrophobic and self-cleaning materials.

Precursor-controlled synthesis of hierarchical ZnO nanostructures, using oligoaniline-coated Au nanoparticle seeds

Science.gov (United States)

Krishnan, Deepti; Pradeep, T.

2009-07-01

Shape-selected synthesis of a large number of zinc oxide (ZnO) nano- and microstructures was achieved by the seed-mediated growth of oligoaniline-coated gold nanoparticle precursors. Distinctive ZnO structures such as nanoplates, nanospheres, microstars, microflowers, microthorns and micromultipods were synthesized by this method. Slightly different shapes were obtained in the absence of the seed solution. This is a fast, low temperature (60 °C) and biomimetic route to make a wide variety of structures. The structure and morphology of the nanostructures were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) were utilized for the characterization of the nanostructures. A growth mechanism for these nanostructures was proposed based on these results. The concentrations of the reacting species were the main parameter causing the changes in the morphologies. The variation in morphologies of these structures is believed to be due to the ability of the seed solution as well as polyvinylpyrrolidone (PVP) to selectively suppress/depress the growth of certain planes, allowing growth to occur only in certain specific directions. Changes in the amount of growth nuclei with varying sodium hydroxide (NaOH) concentration is also seen to affect the morphology of these structures.

Manufacturing and Morphological Analysis of Composite Material of Polystyrene Nanospheres/Cadmium Metal Nanoparticles

Directory of Open Access Journals (Sweden)

Pratama Jujur Wibawa

2013-03-01

Full Text Available A very simple nanocomposite material has been in-situ manufactured from an aqueous polystyrene nanospheres dispersion and cadmium (Cd metal nanoparticles. The manufacturing was performed by using a high frequency of 40 kHz ultrasonic (US agitation for 45 minute at atmospheric pressure and at room temperature 20 oC. No chemical reducing agent and surfactant added in this manufacturing technique due to the US could reduce Cd2+ ions of cadmium nitrate tetrahydrate to Cd atomic metals nanoparticles whereas water molecules could act as a pseudo stabilizer for the manufactured material. A thin film was manufactured from aqueous colloidal nanocomposite material of Polystyrene nanospheres/Cd metal nanoparticles (PSNs/CdMNp fabricated on a hydrophilic silicon wafer. The thin film was then characterized by a JEOL-FESEM for its surface morphology characteristic and by ATR-FTIR spectrometry for its molecular change investigation. It could be clearly observed that surface morphology of the thin film material was not significantly changed under 633 nm wavelength continuous laser radiation exposure for 20 minute. In addition, its ATR-FTIR spectra of wave number peaks around 3400 cm-1 have been totally disappeared under the laser exposure whereas that at around 699 cm-1 and 668 cm-1 have not been significantly changed. The first phenomenon indicated that the hydrogen bond existed in PSNs/CdMNp material was collapsed by the laser exposure. The second phenomena indicated that the PSNs phenyl ring moiety was not totally destroyed under the laser exposure. It was suspected due to the existence of Cd nanoparticles covered throughout the spherical surface of PSNs/CdMNp material particles. Therefore a nice model of material structure of the mentioned PSNs/CdMNp nanocomposite material could be suggested in this research. It could be concluded that this research have been performed since the material structure model of the manufactured PSNs/CdMNp nanocomposite could be

Microstructure Hierarchical Model of Competitive e+-Ps Trapping in Nanostructurized Substances: from Nanoparticle-Uniform to Nanoparticle-Biased Systems.

Science.gov (United States)

Shpotyuk, Oleh; Ingram, Adam; Bujňáková, Zdenka; Baláž, Peter

2017-12-01

Microstructure hierarchical model considering the free-volume elements at the level of interacting crystallites (non-spherical approximation) and the agglomerates of these crystallites (spherical approximation) was developed to describe free-volume evolution in mechanochemically milled As 4 S 4 /ZnS composites employing positron annihilation spectroscopy in a lifetime measuring mode. Positron lifetime spectra were reconstructed from unconstrained three-term decomposition procedure and further subjected to parameterization using x3-x2-coupling decomposition algorithm. Intrinsic inhomogeneities due to coarse-grained As 4 S 4 and fine-grained ZnS nanoparticles were adequately described in terms of substitution trapping in positron and positronium (Ps) (bound positron-electron) states due to interfacial triple junctions between contacting particles and own free-volume defects in boundary compounds. Compositionally dependent nanostructurization in As 4 S 4 /ZnS nanocomposite system was imagined as conversion from o-Ps trapping sites to positron traps. The calculated trapping parameters that were shown could be useful to characterize adequately the nanospace filling in As 4 S 4 /ZnS composites.

Assessment of morphology, topography and chemical composition of water-repellent films based on polystyrene/titanium dioxide nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Bolvardi, Beleta [Chemical Engineering Department, Central Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Seyfi, Javad, E-mail: Jseyfi@gmail.com [Department of Chemical Engineering, Shahrood Branch, Islamic Azad University, P.O. Box 36155-163, Shahrood (Iran, Islamic Republic of); Hejazi, Iman, E-mail: Imanhe64@gmail.com [Applied Science Nano Research Group, ASNARKA, P.C. 1619948753, Tehran (Iran, Islamic Republic of); Otadi, Maryam [Chemical Engineering Department, Central Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Khonakdar, Hossein Ali [Department of Polymer Engineering, Faculty of Engineering, South Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Strasse 6, D-01069 Dresden (Germany); Drechsler, Astrid; Holzschuh, Matthias [Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Strasse 6, D-01069 Dresden (Germany)

2017-02-28

Highlights: • Self-cleaning behavior was attained for PS/TiO{sub 2} nanocomposite films. • A modified phase separation process resulted in a hierarchical morphology. • A proper level of uniformity in surface roughness is mandatory for superhydrophobicity. • The required amount of nanoparticles was highly reduced via the presented method. - Abstract: In this study, polystyrene (PS)/titanium dioxide (TiO{sub 2}) films were fabricated through simple solution casting technique via a modified phase separation process. The presented approach resulted in a remarkable reduction in the required amount of nanoparticles for achieving superhydrophobicity. Scanning electron microscopy (SEM) and 3D confocal microscopy were utilized to characterize surface morphology and topography of samples, respectively. An attempt was made to give an in-depth analysis on the surface rough structure using 3D roughness profiles. It was found that high inclusions of non-solvent and nanoparticles resulted in a stable self-cleaning behavior due to the strong presence of hydrophobic TiO{sub 2} nanoparticles on the surface. Quite unexpectedly, low inclusions of nanoparticles and non-solvent also resulted in superhydrophobic property mainly due to the proper level of induced surface roughness. XPS analysis was also utilized to determine the chemical composition of the films’ surfaces. The results of falling drop experiments showed that the sample containing a higher level of nanoparticles had a much lower mechanical resistance against the induced harsh conditions. All in all, the presented method has shown promising potential in fabrication of superhydrophobic surfaces with self-cleaning behavior using the lowest content of nanoparticles.

The effects of prolonged oral administration of gold nanoparticles on the morphology of hematopoietic and lymphoid organs

Science.gov (United States)

Bucharskaya, Alla B.; Pakhomy, Svetlana S.; Zlobina, Olga V.; Maslyakova, Galina N.; Navolokin, Nikita A.; Matveeva, Olga V.; Khlebtsov, Boris N.; Bogatyrev, Vladimir A.; Khlebtsov, Nikolai G.; Tuchin, Valery V.

2017-02-01

Currently, the usage of gold nanoparticles as photosensitizers and immunomodulators for plasmonic photothermal therapy has attracted a great attention of researches and end-users. In our work, the influence of prolonged peroral administration of gold nanoparticles (GNPs) with different sizes on the morphological changes of hematopoietic and lymphoid organs was investigated. The 24 white outbred male rats weighing 180-220 g were randomly divided into groups and administered orally for 30 days the suspension of gold nanospheres with diameters of 2, 15 and 50 nm at a dosage of 190 μg/kg of animal body weight. To prevent GNPs aggregation in a tissue and enhance biocompatibility, they were functionalized with thiolated polyethylene glycol. The withdrawal of the animals from the experiment and sampling of spleen, lymph nodes and bone marrow tissues for morphological study were performed a day after the last administration. In the spleen the boundary between the red and white pulp was not clearly differ in all experimental groups, lymphoid follicles were significantly increased in size, containing bright germinative centers represented by large blast cells. The stimulation of lymphocyte and myelocytic series of hematopoiesis was recorded at morphological study of the bone marrow. The number of immunoblasts and large lymphocytes was increased in all structural zones of lymph nodes. The more pronounced changes were found in the group with administration of 15 nm nanoparticles. Thus, the morphological changes of cellular components of hematopoietic organs have size-dependent character and indicate the activation of the migration, proliferation and differentiation of immune cells after prolonged oral administration of GNPs.

The synthesis and characterization of platinum nanoparticles: a method of controlling the size and morphology

International Nuclear Information System (INIS)

Long, Nguyen Viet; Hayakawa, Tomokatsu; Lakshminarayana, Gandham; Nogami, Masayuki; Chien, Nguyen Duc; Hirata, Hirohito

2010-01-01

In this paper, Pt nanoparticles with good shapes of nanocubes and nano-octahedra and well-controlled sizes in the range 5-7 and 8-12 nm, respectively, have been successfully synthesized. The modified polyol method by adding silver nitrate and varying the molar ratio of the solutions of silver nitrate and H 2 PtCl 6 has been used to produce Pt nanoparticles of the size and shape to be controlled. The size and morphology of Pt nanoparticles have been studied by transmission electron microscopy (TEM) and high resolution TEM (HRTEM). The results have shown that their very sharp and good shapes exist in the main forms of cubic, cuboctahedral, octahedral and tetrahedral shapes directly related to the crystal nucleation along various directions of the {100} cubic, {111} octahedral and {111} tetrahedral facets during synthesis. In particular, various irregular and new shapes of Pt nanoparticles have been found. Here, it is concluded that the role of silver ions has to be considered as an important factor for promoting and controlling the development of Pt nanoparticles of {100} cubic, {111} octahedral and {111} tetrahedral facets, and also directly orienting the growth and formation of Pt nanoparticles.

Effects of inherent/enhanced solid acidity and morphology of diatomite templates on the synthesis and porosity of hierarchically porous carbon.

Science.gov (United States)

Liu, Dong; Yuan, Peng; Tan, Daoyong; Liu, Hongmei; Fan, Mingde; Yuan, Aihua; Zhu, Jianxi; He, Hongping

2010-12-21

The inherent or enhanced solid acidity of raw or activated diatomite is found to have significant effects on the synthesis of hierarchically porous diatomite-templated carbon with high surface area and special porous structure. The solid acidity makes raw/activated diatomite a catalyst for the generation of porous carbon, and the porous parameters of the carbon products are strongly dependent on the solid acidity of diatomite templates. The morphology of diatomite also dramatically affects the textural structure of porous carbon. Two types of macroporous structures in the carbon product, the partially solid pillars and the ordered hollow tubes, derive from the replication of the central and the edge pores of diatom shell, respectively. The hierarchically porous carbon shows good capability for the adsorption of solvent naphtha and H(2), enabling potential applications in adsorption and gas storage.

Morphological control of Ni/NiO core/shell nanoparticles and production of hollow NiO nanostructures

International Nuclear Information System (INIS)

Chopra, Nitin; Claypoole, Leslie; Bachas, Leonidas G.

2010-01-01

Chemical synthesis coupled with a microwave irradiation process allowed for the control of size (6-40 nm), shape, and shell thickness of Ni/NiO core/shell nanoparticles. In this unique synthetic route, the size of Ni nanoparticles (NiNPs) was strongly influenced by the nickel salt-to-stabilizer ratio and the amount of the stabilizer. Interestingly, it was observed that the shape of the nanoparticles was altered by varying the reaction time, where longer reaction times resulted in annealing effects and rupture of the stabilizer micelle leading to distinct shapes of Ni/NiO core/shell nanostructures. Product cooling rate was another important parameter identified in this study that not only affected the shape, but also the crystal structure of the core/shell nanoparticles. In addition, a simple and cost-effective method of microwave irradiation of NiNPs led to the formation of distinctly shaped hollow NiO nanoparticles. These high surface area core/shell nanoparticles with well-controlled morphologies are important and can lead to significant advancement in the design of improved fuel cells, electrochromic display devices, and catalysis systems.

Morphological control of Ni/NiO core/shell nanoparticles and production of hollow NiO nanostructures

Energy Technology Data Exchange (ETDEWEB)

Chopra, Nitin [University of Alabama, Department of Metallurgical and Materials Engineering, Center for Materials for Information Technology (MINT) (United States); Claypoole, Leslie [Fairmont State University (United States); Bachas, Leonidas G., E-mail: bachas@uky.ed [University of Kentucky, Department of Chemistry (United States)

2010-10-15

Chemical synthesis coupled with a microwave irradiation process allowed for the control of size (6-40 nm), shape, and shell thickness of Ni/NiO core/shell nanoparticles. In this unique synthetic route, the size of Ni nanoparticles (NiNPs) was strongly influenced by the nickel salt-to-stabilizer ratio and the amount of the stabilizer. Interestingly, it was observed that the shape of the nanoparticles was altered by varying the reaction time, where longer reaction times resulted in annealing effects and rupture of the stabilizer micelle leading to distinct shapes of Ni/NiO core/shell nanostructures. Product cooling rate was another important parameter identified in this study that not only affected the shape, but also the crystal structure of the core/shell nanoparticles. In addition, a simple and cost-effective method of microwave irradiation of NiNPs led to the formation of distinctly shaped hollow NiO nanoparticles. These high surface area core/shell nanoparticles with well-controlled morphologies are important and can lead to significant advancement in the design of improved fuel cells, electrochromic display devices, and catalysis systems.

Cellular Internalization and Biocompatibility of Periodic Mesoporous Organosilica Nanoparticles with Tunable Morphologies: From Nanospheres to Nanowires

KAUST Repository

Fatieiev, Yevhen

2017-01-10

This work describes the sol-gel syntheses of para-substituted phenylene-bridged periodic mesoporous organosilica (PMO) nanoparticles (NPs) with tunable morphologies ranging from nanowires to nanospheres. The findings show the key role of the addition of organic co-solvents in the aqueous templates on the final morphologies of PMO NPs. Other factors such as the temperature, the stirring speed, and the amount of organic solvents also influence the shape of PMO NPs. The tuning of the shape of the PMO nanomaterials made it possible to study the influence of the particle morphology on the cellular internalization and biocompatibility.

Au functionalized ZnO rose-like hierarchical structures and their enhanced NO2 sensing performance

Science.gov (United States)

Shingange, K.; Swart, H. C.; Mhlongo, G. H.

2018-04-01

Herein, we present ZnO rose-like hierarchical nanostructures employed as support to Au nanoparticles to produce Au functionalized three dimensional (3D) ZnO hierarchical nanostructures (Au/ZnO) for NO2 detection using a microwave-assisted method. Comparative analysis of NO2 sensing performance between the pristine ZnO and Au/ZnO rose-like structures at 300 °C revealed improved NO2 response and rapid response-recovery times with Au incorporation owing to a combination of high surface accessibility induced by hierarchical nanostructure design and catalytic activity of the small Au nanoparticles. Structural and optical analyses acquired from X-ray diffraction, scanning electron microscopy, transmission electron microscope and photoluminescence spectroscopy were also performed.

Influence of pH on structural morphology and magnetic properties of ordered phase cobalt doped lithium ferrites nanoparticles synthesized by sol-gel method

International Nuclear Information System (INIS)

Srivastava, Manish; Ojha, Animesh K.; Chaubey, S.; Sharma, Prashant K.; Pandey, Avinash C.

2010-01-01

Cobalt doped lithium ferrite nanoparticles were synthesized at different pH by sol-gel method. The effect of pH on the physical properties of cobalt doped lithium ferrite nanoparticles has been investigated. The nanoparticles synthesized at different pH were characterized through X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Raman spectroscopy (RS), Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX) and vibrating sample magnetometer (VSM). The XRD patterns were analyzed to determine the crystal phase of cobalt doped lithium ferrites nanoparticles synthesized at different pH. The XRD results show the formation of impurity free cobalt doped lithium ferrites having ordered phase spinel structure. A similar kind of conclusion was also drawn through the analysis of Raman spectra of the nanoparticles synthesized at different pH. SEM micrographs show that the structural morphology of the nanoparticles is highly sensitive to the pH during the synthesis process. The magnetic properties such as; saturation magnetization (Ms), remnant magnetization (Mr) and coercivety (Hc) have been also investigated and found to be different for the nanoparticles synthesized at different pH, which may be attributed to the different size and surface morphology of the nanoparticles.

Zinc oxide's hierarchical nanostructure and its photocatalytic properties

DEFF Research Database (Denmark)

Kanjwal, Muzafar Ahmed; Sheikh, Faheem A.; Barakat, Nasser A. M.

2012-01-01

In this study, a new hierarchical nanostructure that consists of zinc oxide (ZnO) was produced by the electrospinning process followed by a hydrothermal technique. First, electrospinning of a colloidal solution that consisted of zinc nanoparticles, zinc acetate dihydrate and poly(vinyl alcohol...

Flow rate effect on the structure and morphology of molybdenum oxide nanoparticles deposited by atmospheric-pressure microplasma processing

International Nuclear Information System (INIS)

Bose, Arumugam Chandra; Shimizu, Yoshiki; Mariotti, Davide; Sasaki, Takeshi; Terashima, Kazuo; Koshizaki, Naoto

2006-01-01

Nanoparticles of crystalline molybdenum oxide were prepared by changing the flow rate of plasma gas (2% oxygen balanced by Ar) using an atmospheric-pressure microplasma technique. The morphology and crystalline structure of the nanoparticles were characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The FESEM results revealed that the shape of the deposited nanoparticles depended on the plasma gas flow rate. The TEM results supported the FESEM observations. The transmission electron diffraction (TED) pattern revealed that the obtained nanoparticles changed from MoO 2 to MoO 3 with the flow-rate increase, and correspondingly the nanoparticle size drastically decreased. A process mechanism is proposed from the observations of optical emission spectroscopy (OES) during the process and consumed wire surface analysis from x-ray photoelectron spectroscopy (XPS) and FESEM studies

Kinetic Transition of Crystal Morphology from Nanoparticles to Dendrites during Electron Beam Induced Deposition of Gold

Science.gov (United States)

Park, Jeung Hun; Schneider, Nicholas; Bau, Haim; Kodambaka, Suneel; Ross, Frances

2015-03-01

We studied the kinetic transition from compact nanoparticle to dendritic morphology during electron beam-induced Au deposition using in situ liquid cell-based transmission electron microcopy. Radiolysis of water by electrons generates radicals and molecular species. Hydrated electrons and hydrogen and hydroxide radicals can act as reducing agents and initiate the reduction of the water-soluble precursor, HAuCl4, resulting in the precipitation of Au as nanostructures. We tracked nucleation, growth, and morphological transition of Au from movies recorded in situ, as a function of irradiated dose and liquid thickness. We identified several distinct regimes that depend on the irradiation time: (1) nucleation; (2) linear volumetric growth; (3) formation of dendritic structures; (4) coalescence and dissolution. A diffusion and reaction model for the radiolytic species and metal ions in the confined geometry of the irradiated volume is used to understand the nucleation sites and morphological transitions. We finally describe how nanoparticles can be made to grow in a stepwise manner by switching the supply of Au ions on and off electrochemically, and discuss possibilities for creating more complex nanostructures. This research was partially funded by the National Science Foundation (DMR-1310639, CMMI-1129722, and CBET-1066573).

Local transport properties, morphology and microstructure of ZnO decorated SiO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Van Nostrand, Joseph E [Air Force Research Laboratory, Information Directorate, Rome, NY (United States); Cortez, Rebecca [Union College, Schenectady, NY (United States); Rice, Zachary P; Cady, Nathaniel C; Bergkvist, Magnus, E-mail: Joseph.VanNostrand@rl.af.mil [Albany College of Nanoscale Science and Engineering, Albany, NY (United States)

2010-10-15

We report on a novel, surfactant free method for achieving nanocrystalline ZnO decoration of an SiO{sub 2} nanoparticle at ambient temperature. The size distributions of the naked and decorated SiO{sub 2} nanoparticles are measured by means of dynamic light scattering, and a monodisperse distribution is observed for each. The morphology and microstructure of the nanoparticles are explored using atomic force microscopy and high resolution transmission electron microscopy. Investigation of the optical properties of the ZnO decorated SiO{sub 2} nanoparticles shows absorption at 350 nm. This blue shift in absorption as compared to bulk ZnO is shown to be consistent with quantum confinement effects due to the small size of the ZnO nanocrystals. Finally, the local electronic transport properties of the nanoparticles are explored by scanning conductance atomic force microscopy. A memristive hysteresis in the transport properties of the individual ZnO decorated SiO{sub 2} nanoparticles is observed. Optical absorption measurements suggest the presence of oxygen vacancies, whose migration and annihilation appear to contribute to the dynamic conduction properties of the ZnO decorated nanoparticles. We believe this to be the first demonstration of a ZnO decorated SiO{sub 2} nanoparticle, and this represents a simple yet powerful way of achieving the optical and electrical properties of ZnO in combination with the simplicity of SiO{sub 2} synthesis.

Hierarchically Nanostructured Materials for Sustainable Environmental Applications

Directory of Open Access Journals (Sweden)

Zheng eRen

2013-11-01

Full Text Available This article presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions and multiple functionalities towards water remediation, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology.

Hierarchical Micro-Nano Coatings by Painting

Science.gov (United States)

Kirveslahti, Anna; Korhonen, Tuulia; Suvanto, Mika; Pakkanen, Tapani A.

2016-03-01

In this paper, the wettability properties of coatings with hierarchical surface structures and low surface energy were studied. Hierarchically structured coatings were produced by using hydrophobic fumed silica nanoparticles and polytetrafluoroethylene (PTFE) microparticles as additives in polyester (PES) and polyvinyldifluoride (PVDF). These particles created hierarchical micro-nano structures on the paint surfaces and lowered or supported the already low surface energy of the paint. Two standard application techniques for paint application were employed and the presented coatings are suitable for mass production and use in large surface areas. By regulating the particle concentrations, it was possible to modify wettability properties gradually. Highly hydrophobic surfaces were achieved with the highest contact angle of 165∘. Dynamic contact angle measurements were carried out for a set of selected samples and low hysteresis was obtained. Produced coatings possessed long lasting durability in the air and in underwater conditions.

The effect of the triblock properties on the morphologies and photophysical properties of nanoparticle loaded with carboxylic dendrimer phthalocyanine

Science.gov (United States)

Lv, Huafei; Chen, Zhe; Yu, Xinxin; Pan, Sujuan; Zhang, Tiantian; Xie, Shusen; Yang, Hongqin; Peng, Yiru

2016-09-01

Photodynamic therapy (PDT) is an emerging alternative treatment for various cancers and age-related macular degeneration. Phthalocyanines (Pcs) and their substituted derivatives are under intensive investigation as the second generation photosensitizers. A big challenge for the application of Pcs is poor solubility and limited accumulation in the tumor tissues, which severely reduced its PDT efficacy. Nano-delivery systems such as polymeric micelles are promising tools for increasing the solubility and improving delivery efficiency of Pcs for PDT application. In this paper, nanoparticles of amphiphilic triblock copolymer poly(L-lysine)-b-poly (ethylene glycol)-b-poly(L-lysine) were developed to encapsulate 1-2 generation carboxylic poly (benzyl aryl ether) dendrimer. The morphologies and photophysical properties of polymeric nanoparticles loaded with 1-2 generation dendritic phthalocyanines (G1-ZnPc(COOH)8/m and G2-ZnPc(COOH)16/m) were studied by AFM, UV/Vis and fluorescent spectroscopic method. The morphologies of self-assembled PLL-PEG-PLL aggregates exhibited concentration dependence. Its morphologies changed from cocoon-like to spheral. The diameters of G1-ZnPc(COOH)8/m and G2-ZnPc(COOH)16/m were in the range of 33-147 nm, increasing with the increase of the concentration of PLL-PEG-PLL. The morphologies of G2-ZnPc(COOH)16/m also changed from cocoon-like to sphere with the increase of the concentration of PLL-PEG-PLL. It was found that, the no obviously Q change was observed between the free phthalocyanines and nanoparticles. The fluorescence intensity of polymer nanoparticles were higher enhanced compared with free dendritic phthalocyanines. The dendrimer phthalocyanine loaded with poly(L-lysine)-b-poly (ethylene glycol)-b-poly(L-lysine) presented suitable physical stability, improved photophysical properties suggesting it may be considered as a promising formulation for PDT.

Morphological impact on the reaction kinetics of size-selected cobalt oxide nanoparticles

International Nuclear Information System (INIS)

Bartling, Stephan; Meiwes-Broer, Karl-Heinz; Barke, Ingo; Pohl, Marga-Martina

2015-01-01

Apart from large surface areas, low activation energies are essential for efficient reactions, particularly in heterogeneous catalysis. Here, we show that not only the size of nanoparticles but also their detailed morphology can crucially affect reaction kinetics, as demonstrated for mass-selected, soft-landed, and oxidized cobalt clusters in a 6 nm to 18 nm size range. The method of reflection high-energy electron diffraction is extended to the quantitative determination of particle activation energies which is applied for repeated oxidation and reduction cycles at the same particles. We find unexpectedly small activation barriers for the reduction reaction of the largest particles studied, despite generally increasing barriers for growing sizes. We attribute these observations to the interplay of reaction-specific material transport with a size-dependent inner particle morphology

One-Pot Synthesis of Hierarchical Flower-Like Pd-Cu Alloy Support on Graphene Towards Ethanol Oxidation

Science.gov (United States)

Zhang, Jingyi; Feng, Anni; Bai, Jie; Tan, Zhibing; Shao, Wenyao; Yang, Yang; Hong, Wenjing; Xiao, Zongyuan

2017-09-01

The synergetic effect of alloy and morphology of nanocatalysts play critical roles towards ethanol electrooxidation. In this work, we developed a novel electrocatalyst fabricated by one-pot synthesis of hierarchical flower-like palladium (Pd)-copper (Cu) alloy nanocatalysts supported on reduced graphene oxide (Pd-Cu(F)/RGO) for direct ethanol fuel cells. The structures of the catalysts were characterized by using scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectrometer (XPS). The as-synthesized Pd-Cu(F)/RGO nanocatalyst was found to exhibit higher electrocatalytic performances towards ethanol electrooxidation reaction in alkaline medium in contrast with RGO-supported Pd nanocatalyst and commercial Pd black catalyst in alkaline electrolyte, which could be attributed to the formation of alloy and the morphology of nanoparticles. The high performance of nanocatalyst reveals the great potential of the structure design of the supporting materials for the future fabrication of nanocatalysts.

Structure and morphologies of ZnO nanoparticles synthesized by pulsed laser ablation in liquid: Effects of temperature and energy fluence

Energy Technology Data Exchange (ETDEWEB)

Guillén, G. García; Palma, M.I. Mendivil [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455 (Mexico); Krishnan, B. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455 (Mexico); Universidad Autónoma de Nuevo León – Centro de Innovación, Investigación y Desarrollo de Ingeniería y Tecnología, Apodaca, Nuevo León 66600 (Mexico); Avellaneda, D.; Castillo, G.A.; Roy, T.K. Das [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455 (Mexico); and others

2015-07-15

Zinc oxide nanoparticles were prepared by pulsed laser ablation of a zinc metal target at different water temperatures (room temperature, 50, 70 and 90 °C). Ablation was carried out using 532 nm output from a pulsed (10 ns, 10 Hz) Nd:YAG laser at three different laser fluence. Analysis of the morphology, crystalline phase, elemental composition, optical and luminescent properties were done using Transmission Electron Microscopy (TEM), X-Ray Photoelectron Spectroscopy (XPS), UV–visible absorption spectroscopy and photoluminescence spectroscopy. TEM analysis showed that a change in temperature resulted in ZnO and Zn(OH){sub 2} nanoparticles with different sizes and morphologies. XPS results confirmed the compositions and chemical states of these nanoparticles. These zinc nanomaterials showed emission in the ultraviolet (UV) and blue regions. The results of this work demonstrated that by varying the liquid medium temperature, the structure, composition, morphology and optical properties of the nanomaterials could be modified during pulsed laser ablation in liquid. - Graphical abstract: Display Omitted - Highlights: • Zinc nanomaterial colloids were synthesized by PLAL. • Effects of laser fluence and the distilled water temperature were analyzed. • The final structure varied with the distilled water temperature and laser fluence. • The morphology was dependent on the distilled water temperature and laser fluence. • Zinc nanocolloids showed emission in the UV and blue region.

Structure and morphologies of ZnO nanoparticles synthesized by pulsed laser ablation in liquid: Effects of temperature and energy fluence

International Nuclear Information System (INIS)

Guillén, G. García; Palma, M.I. Mendivil; Krishnan, B.; Avellaneda, D.; Castillo, G.A.; Roy, T.K. Das

2015-01-01

Zinc oxide nanoparticles were prepared by pulsed laser ablation of a zinc metal target at different water temperatures (room temperature, 50, 70 and 90 °C). Ablation was carried out using 532 nm output from a pulsed (10 ns, 10 Hz) Nd:YAG laser at three different laser fluence. Analysis of the morphology, crystalline phase, elemental composition, optical and luminescent properties were done using Transmission Electron Microscopy (TEM), X-Ray Photoelectron Spectroscopy (XPS), UV–visible absorption spectroscopy and photoluminescence spectroscopy. TEM analysis showed that a change in temperature resulted in ZnO and Zn(OH) 2 nanoparticles with different sizes and morphologies. XPS results confirmed the compositions and chemical states of these nanoparticles. These zinc nanomaterials showed emission in the ultraviolet (UV) and blue regions. The results of this work demonstrated that by varying the liquid medium temperature, the structure, composition, morphology and optical properties of the nanomaterials could be modified during pulsed laser ablation in liquid. - Graphical abstract: Display Omitted - Highlights: • Zinc nanomaterial colloids were synthesized by PLAL. • Effects of laser fluence and the distilled water temperature were analyzed. • The final structure varied with the distilled water temperature and laser fluence. • The morphology was dependent on the distilled water temperature and laser fluence. • Zinc nanocolloids showed emission in the UV and blue region

Morphology and dispersion of FeCo alloy nanoparticles dispersed in a matrix of IR pyrolized polyvinyl alcohol

Science.gov (United States)

Vasilev, A. A.; Dzidziguri, E. L.; Muratov, D. G.; Zhilyaeva, N. A.; Efimov, M. N.; Karpacheva, G. P.

2018-04-01

Metal-carbon nanocomposites consisting of FeCo alloy nanoparticles dispersed in a carbon matrix were synthesized by the thermal decomposition method of a precursor based on polyvinyl alcohol and metals salts. The synthesized powders were investigated by X-ray diffraction (XRD), X-ray fluorescent spectrometry (XRFS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Surface characteristics of materials were measured by BET-method. The morphology and dispersity of metal nanoparticles were studied depending on the metals ratio in the composite.

Spectrophotometric evaluation of surface morphology dependent catalytic activity of biosynthesized silver and gold nanoparticles using UV–vis spectra: A comparative kinetic study

Energy Technology Data Exchange (ETDEWEB)

Ankamwar, Balaprasad, E-mail: bankamwar@yahoo.com [Bio-inspired Materials Research Laboratory, Department of Chemistry, Savitribai Phule Pune University, Ganeshkhind, Pune 411007 (India); Kamble, Vaishali; Sur, Ujjal Kumar [Bio-inspired Materials Research Laboratory, Department of Chemistry, Savitribai Phule Pune University, Ganeshkhind, Pune 411007 (India); Santra, Chittaranjan [Department of Chemistry, Netaji Nagar Day College, Regent Park, Kolkata 700092 (India)

2016-03-15

Graphical abstract: - Highlights: • The biosynthesized silver nanoparticles were stable for 6 months and used as effective SERS active substrate. • They are effective catalyst in the chemical reduction of 4-nitrophenol to 4-aminophenol. • Comparative catalytic efficiency of both silver and gold nanoparticles was studied spectrophotometrically. • Our results demonstrate surface morphology dependent catalytic activity of both nanoparticles. - Abstract: The development of eco-friendly and cost-effective synthetic protocol for the preparation of nanomaterials, especially metal nanoparticles is an emerging area of research in nanotechnology. These metal nanoparticles, especially silver can play a crucial role in various catalytic reactions. The biosynthesized silver nanoparticles described here was very stable up to 6 months and can be further exploited as an effective catalyst in the chemical reduction of 4-nitrophenol to 4-aminophenol. The silver nanoparticles were utilized as an efficient surface-enhanced Raman scattering (SERS) active substrate using Rhodamine 6G as Raman probe molecule. We have also carried out systematic comparative studies on the catalytic efficiency of both silver and gold nanoparticles using UV–vis spectra to monitor the above reaction spectrophotometrically. We find that the reaction follows pseudo-first order kinetics and the catalytic activity can be explained by a simple model based on Langmuir–Hinshelwood mechanism for heterogeneous catalysis. We also find that silver nanoparticles are more efficient as a catalyst compare to gold nanoparticles in the reduction of 4-nitrophenol to 4-aminophenol, which can be explained by the morphology of the nanoparticles as determined by transmission electron microscopy.

Spectrophotometric evaluation of surface morphology dependent catalytic activity of biosynthesized silver and gold nanoparticles using UV–vis spectra: A comparative kinetic study

International Nuclear Information System (INIS)

Ankamwar, Balaprasad; Kamble, Vaishali; Sur, Ujjal Kumar; Santra, Chittaranjan

2016-01-01

Graphical abstract: - Highlights: • The biosynthesized silver nanoparticles were stable for 6 months and used as effective SERS active substrate. • They are effective catalyst in the chemical reduction of 4-nitrophenol to 4-aminophenol. • Comparative catalytic efficiency of both silver and gold nanoparticles was studied spectrophotometrically. • Our results demonstrate surface morphology dependent catalytic activity of both nanoparticles. - Abstract: The development of eco-friendly and cost-effective synthetic protocol for the preparation of nanomaterials, especially metal nanoparticles is an emerging area of research in nanotechnology. These metal nanoparticles, especially silver can play a crucial role in various catalytic reactions. The biosynthesized silver nanoparticles described here was very stable up to 6 months and can be further exploited as an effective catalyst in the chemical reduction of 4-nitrophenol to 4-aminophenol. The silver nanoparticles were utilized as an efficient surface-enhanced Raman scattering (SERS) active substrate using Rhodamine 6G as Raman probe molecule. We have also carried out systematic comparative studies on the catalytic efficiency of both silver and gold nanoparticles using UV–vis spectra to monitor the above reaction spectrophotometrically. We find that the reaction follows pseudo-first order kinetics and the catalytic activity can be explained by a simple model based on Langmuir–Hinshelwood mechanism for heterogeneous catalysis. We also find that silver nanoparticles are more efficient as a catalyst compare to gold nanoparticles in the reduction of 4-nitrophenol to 4-aminophenol, which can be explained by the morphology of the nanoparticles as determined by transmission electron microscopy.

Hierarchical structured graphene/metal oxide/porous carbon composites as anode materials for lithium-ion batteries

International Nuclear Information System (INIS)

Guo, Rong; Yue, Wenbo; Ren, Yu; Zhou, Wuzong

2016-01-01

Highlights: • CeO 2 and Co 3 O 4 nanoparticles display different behavior within CMK-3. • CMK-3-CeO 2 and Co 3 O 4 show various electrochemical properties • CMK-3-CeO 2 and Co 3 O 4 are further wrapped by graphene nanosheets. • Graphene-encapsulated composites show better electrochemical performances. - Abstract: As a novel anode material for lithium-ion batteries, CeO 2 displays imperceptible volumetric and morphological changes during the lithium insertion and extraction processes, and thereby exhibits good cycling stability. However, the low theoretical capacity and poor electronic conductivity of CeO 2 hinder its practical application. In contrast, Co 3 O 4 possesses high theoretical capacity, but undergoes huge volume change during cycling. To overcome these issues, CeO 2 and Co 3 O 4 nanoparticles are formed inside the pores of CMK-3 and display various electrochemical behaviors due to the different morphological structures of CeO 2 and Co 3 O 4 within CMK-3. Moreover, the graphene/metal oxide/CMK-3 composites with a hierarchical structure are then prepared and exhibit better electrochemical performances than metal oxides with or without CMK-3. This novel synthesis strategy is hopefully employed in the electrode materials design for Li-ion batteries or other energy conversion and storage devices.

Effect of capping agent on the morphology, size and optical properties of In{sub 2}O{sub 3} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Latha, Ch. Kanchana; Aparna, Y. [Department of Physics, Jawaharlal Nehru Technological University Hyderabad (JNTUH), College of Engineering Hyderabad (CEH), Telangana (India); Raghasudha, Mucherla; Veerasomaiah, P., E-mail: raghasudha_m@yahoo.co.in [Department of Chemistry, University College of Science, Osmania University, Hyderabad, Telangana (India); Ramchander, M. [Department of Bio Chemistry, Mahatma Gandhi University, Nalgonda, Telangana (India); Ravinder, D. [Department of Physics, Osmania University, Hyderabad, Telangana (India); Jaipal, K. [Inorganic & Physical Chemistry Division, Indian Institute of Chemical Technology (IICT), Hyderabad, Telangana (India); Shridhar, D. [Department of Physics, Khairatabad Government Degree College, Hyderabad, Telangana (India)

2017-01-15

The Indium Oxide (In{sub 2}O{sub 3}) nanoparticles were synthesized through Acacia gum mediated method with the surfactants CTAB (Cetyl Trimethyl Ammonium Bromide) and SDBS (Sodium Docecyl Benzene Sulfonate). The characterization of the synthesized In{sub 2}O{sub 3} nanoparticles was carried out by XRD, FTIR, RAMAN, TEM, SEM, EDAX, UV-Vis and PL techniques. TG-DTA analysis was performed to know the calcination temperature of In{sub 2}O{sub 3} nanoparticles. XRD analysis confirmed the crystalline nature of the synthesized In{sub 2}O{sub 3} nanoparticles. The morphology and chemical composition were characterized by TEM, SEM and EDAX respectively. It was observed that morphology and size of synthesized nanoparticles measured by TEM and SEM analysis were dependent on the type of capping agent (surfactant) used. Raman and UV-Vis spectral analysis confirmed that the band gap value of CTAB capped In{sub 2}O{sub 3} particles were larger than the SDBS capped In{sub 2}O{sub 3} particles. FTIR analysis indicated that the bands were stretched in In{sub 2}O{sub 3} particles capped by SDBS than by CTAB. From the photoluminescence studies (PL technique), a blue shift in the emission peaks of CTAB and SDBS capped In{sub 2}O{sub 3} particles was observed that indicates larger optical band gap than the bulk. (author)

Morphology evolution of gold nanoparticles as function of time, temperature, and Au(III)/sodium ascorbate molar ratio

Energy Technology Data Exchange (ETDEWEB)

Priolisi, Ornella, E-mail: ornella.priolisi@depretto.gov.it [ITIS “De Pretto” (Italy); Fabrizi, Alberto, E-mail: fabrizi@gest.unipd.it [University of Padova, Department of Management and Engineering (Italy); Deon, Giovanna, E-mail: giovanna.deon@depretto-vi.it [ITIS “De Pretto” (Italy); Bonollo, Franco, E-mail: bonollo@gest.unipd.it [University of Padova, Department of Management and Engineering (Italy); Cattini, Stefano, E-mail: stefano.cattini@unimore.it [University of Modena and Reggio Emilia, Department of Engineering Enzo Ferrari (Italy)

2016-01-15

In this work the morphology evolution of Au nanoparticles (AuNPs), obtained by direct reduction, was studied as a function of time, temperature, and Au(III)/sodium ascorbate molar ratio. The NPs morphology was examined by transmission electron microscope with image analysis, while time evolution was investigated by visible and near-infrared absorption spectroscopy and dynamic light scattering. It is found that initially formed star-like NPs transform in more spheroidal particles and the evolution appears more rapid by increasing the temperature while a large amount of reducing agent prevents the remodeling of AuNPs. An explication of morphology evolution is proposed.

Hierarchical Cluster Analysis of Three-Dimensional Reconstructions of Unbiased Sampled Microglia Shows not Continuous Morphological Changes from Stage 1 to 2 after Multiple Dengue Infections in Callithrix penicillata

Science.gov (United States)

Diniz, Daniel G.; Silva, Geane O.; Naves, Thaís B.; Fernandes, Taiany N.; Araújo, Sanderson C.; Diniz, José A. P.; de Farias, Luis H. S.; Sosthenes, Marcia C. K.; Diniz, Cristovam G.; Anthony, Daniel C.; da Costa Vasconcelos, Pedro F.; Picanço Diniz, Cristovam W.

2016-01-01

It is known that microglial morphology and function are related, but few studies have explored the subtleties of microglial morphological changes in response to specific pathogens. In the present report we quantitated microglia morphological changes in a monkey model of dengue disease with virus CNS invasion. To mimic multiple infections that usually occur in endemic areas, where higher dengue infection incidence and abundant mosquito vectors carrying different serotypes coexist, subjects received once a week subcutaneous injections of DENV3 (genotype III)-infected culture supernatant followed 24 h later by an injection of anti-DENV2 antibody. Control animals received either weekly anti-DENV2 antibodies, or no injections. Brain sections were immunolabeled for DENV3 antigens and IBA-1. Random and systematic microglial samples were taken from the polymorphic layer of dentate gyrus for 3-D reconstructions, where we found intense immunostaining for TNFα and DENV3 virus antigens. We submitted all bi- or multimodal morphological parameters of microglia to hierarchical cluster analysis and found two major morphological phenotypes designated types I and II. Compared to type I (stage 1), type II microglia were more complex; displaying higher number of nodes, processes and trees and larger surface area and volumes (stage 2). Type II microglia were found only in infected monkeys, whereas type I microglia was found in both control and infected subjects. Hierarchical cluster analysis of morphological parameters of 3-D reconstructions of random and systematic selected samples in control and ADE dengue infected monkeys suggests that microglia morphological changes from stage 1 to stage 2 may not be continuous. PMID:27047345

Synthesis and morphological examination of high-purity Ca(OH)2 nanoparticles suitable to consolidate porous surfaces

Science.gov (United States)

Madrid, Juan Antonio; Lanzón, Marcos

2017-12-01

Adequate synthetic methods to obtain pure Ca(OH)2 nanoparticles are scarcely documented in the literature. This paper presents a complete methodology to obtain highly-pure Ca(OH)2 nanoparticles that are appropriate for strengthening heritage materials. The precipitation synthesis was operated in controlled atmosphere to avoid carbonation by atmospheric CO2. A complete purification method was developed to eliminate the sodium chloride generated in the reaction. Several analytical techniques, such as electrical conductivity, pH, ion chromatography, X-ray diffraction (XRD) and thermogravimetric analysis coupled to mass spectrometry (TGA-MS) were used to analyse both the aqueous medium and solid phase. The amount of material obtained in the synthesis (yield) was quantified throughout the purification procedure. The influence of temperature on the nanoparticles' size and stability was studied by transmission electron microscopy (HRTEM) and sedimentation tests (light scattering). It was found that the synthesis yielded high-purity nanoparticles, whose morphological features were greatly affected by the reaction temperature.

Hierarchically assembled Au microspheres and sea urchin-like architectures: formation mechanism and SERS study.

Science.gov (United States)

Wang, Xiansong; Yang, Da-Peng; Huang, Peng; Li, Min; Li, Chao; Chen, Di; Cui, Daxiang

2012-12-21

The hierarchically assembled Au microspheres/sea urchin-like structures have been synthesized in aqueous solution at room temperature with and without proteins (bovine serum albumin, BSA) as mediators. The average diameter of an individual Au microsphere is 300-600 nm, which is composed of some compact nanoparticles with an average diameter of about 15 nm. Meanwhile, the sea urchin-like Au architecture exhibits an average diameter of 600-800 nm, which is made up of some nanopricks with an average length of 100-200 nm. These products are characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electronic microscopy (TEM). It is found that the BSA and ascorbic acid (AA) have great effects on the morphology of the resulting products. Two different growth mechanisms are proposed. The study on surface enhanced Raman scattering (SERS) activities is also carried out between Au microspheres and Au sea urchin-like architectures. It is found that Au urchin-like architectures possess much higher SERS activity than the Au microspheres. Our work may shed light on the design and synthesis of hierarchically self-assembled 3D micro/nano-architectures for SERS, catalysis and biosensors.

Affecting the morphology of silver deposition on carbon nanotube surface: From nanoparticles to dendritic (tree-like) nanostructures

Energy Technology Data Exchange (ETDEWEB)

Forati-Nezhad, Mohsen [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Mir Mohamad Sadeghi, Gity, E-mail: gsadeghi@aut.ac.ir [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Yaghmaie, Frank [Northern California Nanotechnology Center, University of California, Davis, CA 95616 (United States); Alimohammadi, Farbod [Young Researchers and Elite Club, South Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

2015-01-01

Chemical reduction was used to synthesize silver crystals on the surface of multiwall carbon nanotubes (MWCNTs) in the presence of acetone, N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone, and isopropyl alcohol as solvent. DMF and sodium dodecyl sulfate were used as a reducing and a stabilizing agent, respectively. The structure and nature of hybrid MWCNT/silver were characterized by Raman spectroscopy, FTIR spectroscopy, transmission electron microscopy (TEM), and field emission scanning electron microscope (FESEM). The presence of silver crystals on the nanotubes was confirmed by XRD. The results show the formation of silver crystals on the MWCNT surface and indicate that the morphology of silver crystals can be control by changing the solvent. The type of solvent is an effective parameter that affects the particle size and morphological transition from nanoparticles to silver trees. - Highlights: • The silver crystals are grown on the CNT surface by chemical reduction method. • The morphology of silver crystals is controlled by changing the solvent. • Silver nanoparticles and dendritic nanostructures on CNT surface are achieved. • Any change in structure and surface defects by synthesis condition is investigated.

Renewable Wood Pulp Paper Reactor with Hierarchical Micro/Nanopores for Continuous-Flow Nanocatalysis.

Science.gov (United States)

Koga, Hirotaka; Namba, Naoko; Takahashi, Tsukasa; Nogi, Masaya; Nishina, Yuta

2017-06-22

Continuous-flow nanocatalysis based on metal nanoparticle catalyst-anchored flow reactors has recently provided an excellent platform for effective chemical manufacturing. However, there has been limited progress in porous structure design and recycling systems for metal nanoparticle-anchored flow reactors to create more efficient and sustainable catalytic processes. In this study, traditional paper is used for a highly efficient, recyclable, and even renewable flow reactor by tailoring the ultrastructures of wood pulp. The "paper reactor" offers hierarchically interconnected micro- and nanoscale pores, which can act as convective-flow and rapid-diffusion channels, respectively, for efficient access of reactants to metal nanoparticle catalysts. In continuous-flow, aqueous, room-temperature catalytic reduction of 4-nitrophenol to 4-aminophenol, a gold nanoparticle (AuNP)-anchored paper reactor with hierarchical micro/nanopores provided higher reaction efficiency than state-of-the-art AuNP-anchored flow reactors. Inspired by traditional paper materials, successful recycling and renewal of AuNP-anchored paper reactors were also demonstrated while high reaction efficiency was maintained. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Effect of Zn and Ni substitution on structural, morphological and magnetic properties of tin oxide nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Bhuvana, S. [Research and Development Centre, Bharathiar University, Coimbatore 641046, Tamilnadu (India); Department of Physics, Dr. NGP Institute of Technology, Coimbatore 641048, Tamilnadu (India); Ramalingam, H.B.; Vadivel, K. [Department of Physics, Government Arts College, Udumalpet 642126, Tamilnadu (India); Ranjith Kumar, E., E-mail: ranjueaswar@gmail.com [Department of Physics, Dr. NGP Institute of Technology, Coimbatore 641048, Tamilnadu (India); Ayesh, Ahmad I. [Department of Math., Stat. and Physics, Qatar University, Doha (Qatar)

2016-12-01

Structural, morphological, optical and magnetic properties of Zn and Zn–Ni co-doped tin oxide (SnO{sub 2}) nanoparticles synthesized by sol-gel method. The influence of doping concentration on phase and particle size of the nanoparticles was determined by X-ray diffraction. The XRD study reveals that the lattice constant and crystallite size of the samples decrease with the increase of doping concentration. The change in the band gap energy of SnO{sub 2} nanoparticles influenced more by doping with Zn and Ni. The external morphology and particle size were recorded by SEM and TEM. The results indicated that Ni{sup 2+} ions would uniformly substituted into the Zn{sup 2+} sites of SnO{sub 2} lattice. The substitution of Ni creates a vital change in magnetic properties that has been measured by vibrating sample magnetometer (VSM). - Highlights: • Sn{sub 2-(x+y)} Ni{sub x}Zn{sub y}O{sub 2}, (x=y=0.07 to 0.10) nano particles are prepared by simple sol gel method. • X-ray diffraction data confirms the single phase rutile tetragonal structure. • The VSM was used to confirm, the codoping of (Ni, Zn) increases the magnetic moment of the sample prepared. • Inducing ferromagnetism in sample makes it suitable for future spintronics applications.

Hyaluronic acid-coated chitosan nanoparticles: molecular weight-dependent effects on morphology and hyaluronic acid presentation.

Science.gov (United States)

Almalik, Abdulaziz; Donno, Roberto; Cadman, Christopher J; Cellesi, Francesco; Day, Philip J; Tirelli, Nicola

2013-12-28

Chitosan nanoparticles are popular carriers for the delivery of macromolecular payloads, e.g. nucleic acids. In this study, nanoparticles were prepared via complexation with triphosphate (TPP) anions and were successively coated with hyaluronic acid (HA). Key variables of the preparative process (e.g. chitosan and HA molecular weight) were optimised in view of the maximisation of loading with DNA, of the Zeta potential and of the dimensional stability, and the resulting particles showed excellent storage stability. We have focused on the influence of chitosan molecular weight on nanoparticle properties. Larger molecular weight increased their porosity (=decreased cross-link density), and this caused also larger dimensional changes in response to variations in osmotic pressure or upon drying. The dependency of nanoparticle porosity on chitosan molecular weight had a profound effect on the adsorption of HA on the nanoparticles; HA was apparently able to penetrate deeply into the more porous high molecular weight (684 kDa) chitosan nanoparticles, while it formed a corona around those composed of more densely cross-linked low molecular weight (25 kDa) chitosan. Atomic Force Microscopy (AFM) allowed not only to highlight the presence of this corona, but also to estimate its apparent thickness to about 20-30 nm (in a dry state). The different morphology has a significant effect on the way HA is presented to biomolecules, and this has specific relevance in relation to interactions with HA receptors (e.g. CD44) that influence kinetics and mechanism of nanoparticle uptake. Finally, it is worth to mention that chitosan molecular weight did not appear to greatly affect the efficiency of nanoparticle loading with DNA, but significantly influenced its chitosanase-triggered release, with high molecular chitosan nanoparticles seemingly more prone to degradation by this enzyme. © 2013.

Diketopyrrolopyrrole-based polymer:fullerene nanoparticle films with thermally stable morphology for organic photovoltaic applications

Energy Technology Data Exchange (ETDEWEB)

Holmes, Natalie P. [Univ. of Newcastle, Callaghan NSW (Australia). Centre for Organic Electronics; Vaughan, Ben [Univ. of Newcastle, Callaghan NSW (Australia). Centre for Organic Electronics; CSIRO Energy Technology, Newcastle (Australia); Williams, Evan L. [Inst. of Materials Research and Engineering (IMRE), Agency for Science, Technology, and Research (A*STAR), Singapore (Singapore); Kroon, Renee [Univ. of South Australia, Mawson Lakes Campus, SA (Australia). Ian Wark Research Inst.; Chalmers Univ. of Technology, Goteborg (Sweden). Dept. of Chemical and Biological Engineering/Polymer Technology; Anderrson, Mats R. [Univ. of South Australia, Mawson Lakes Campus, SA (Australia). Ian Wark Research Inst.; Chalmers Univ. of Technology, Goteborg (Sweden). Dept. of Chemical and Biological Engineering/Polymer Technology; Kilcoyne, A. L. David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS); Sonar, Prashant [Inst. of Materials Research and Engineering (IMRE), Agency for Science, Technology, and Research (A*STAR), Singapore (Singapore); Queensland Univ. of Technology (QUT), Brisbane (Australia). School of Chemistry, Physics and Mechanical Engineering; Zhou, Xiaojing [Univ. of Newcastle, Callaghan NSW (Australia). Centre for Organic Electronics; Dastoor, Paul C. [Univ. of Newcastle, Callaghan NSW (Australia). Centre for Organic Electronics; Belcher, Warwick J. [Univ. of Newcastle, Callaghan NSW (Australia). Centre for Organic Electronics

2017-02-02

Polymer:fullerene nanoparticles (NPs) offer two key advantages over bulk heterojunction (BHJ) films for organic photovoltaics (OPVs), water-processability and potentially superior morphological control. Once an optimal active layer morphology is reached, maintaining this morphology at OPV operating temperatures is key to the lifetime of a device. Here in this paper we study the morphology of the PDPP-TNT (poly{3,6-dithiophene-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-naphthalene}):PC₇₁BM ([6,6]-phenyl C₇₁ butyric acid methyl ester) NP system and then compare the thermal stability of NP and BHJ films to the common poly(3-hexylthiophene) (P3HT): phenyl C₆₁ butyric acid methyl ester (PC₆₁BM) system. We find that material T_g plays a key role in the superior thermal stability of the PDPP-TNT:PC₇₁BM system; whereas for the P3HT:PC₆₁BM system, domain structure is critical.

Molecular simulation of adsorption and transport in hierarchical porous materials.

Science.gov (United States)

Coasne, Benoit; Galarneau, Anne; Gerardin, Corine; Fajula, François; Villemot, François

2013-06-25

Adsorption and transport in hierarchical porous solids with micro- (~1 nm) and mesoporosities (>2 nm) are investigated by molecular simulation. Two models of hierarchical solids are considered: microporous materials in which mesopores are carved out (model A) and mesoporous materials in which microporous nanoparticles are inserted (model B). Adsorption isotherms for model A can be described as a linear combination of the adsorption isotherms for pure mesoporous and microporous solids. In contrast, adsorption in model B departs from adsorption in pure microporous and mesoporous solids; the inserted microporous particles act as defects, which help nucleate the liquid phase within the mesopore and shift capillary condensation toward lower pressures. As far as transport under a pressure gradient is concerned, the flux in hierarchical materials consisting of microporous solids in which mesopores are carved out obeys the Navier-Stokes equation so that Darcy's law is verified within the mesopore. Moreover, the flow in such materials is larger than in a single mesopore, due to the transfer between micropores and mesopores. This nonzero velocity at the mesopore surface implies that transport in such hierarchical materials involves slippage at the mesopore surface, although the adsorbate has a strong affinity for the surface. In contrast to model A, flux in model B is smaller than in a single mesopore, as the nanoparticles act as constrictions that hinder transport. By a subtle effect arising from fast transport in the mesopores, the presence of mesopores increases the number of molecules in the microporosity in hierarchical materials and, hence, decreases the flow in the micropores (due to mass conservation). As a result, we do not observe faster diffusion in the micropores of hierarchical materials upon flow but slower diffusion, which increases the contact time between the adsorbate and the surface of the microporosity.

Hierarchical carbon-coated acanthosphere-like Li4Ti5O12 microspheres for high-power lithium-ion batteries

Science.gov (United States)

Sha, Yujing; Xu, Xiaomin; Li, Li; Cai, Rui; Shao, Zongping

2016-05-01

In this work, carbon-coated hierarchical acanthosphere-like Li4Ti5O12 microspheres (denoted as AM-LTO) were prepared via a two-step hydrothermal process with low-cost glucose as the organic carbon source. The hierarchical porous microspheres had open structures with diameters of 4-6 μm, which consisted of a bunch of willow leaf-like nanosheets. Each nanosheet was comprised of Li4Ti5O12 nanoparticles that are 20 nm in size and coated by a thin carbon layer. When applied as the anode material for lithium-ion batteries (LIBs), the AM-LTO presented outstanding rate and cycling performance due to its unique morphologies. A high capacity of 145.6 mAh g-1 was achieved for AM-LTO at a rate of 40C (1C = 175 mAh g-1). In contrast, the sample synthesized without glucose as carbon source (denoted as S-LTO) experienced an obvious structural collapse during the hydrothermal reaction and presented a specific capacity of only 67 mAh g-1 at 1C, which further decreased to 14 mAh g-1 at 40C. Further morphological growth of the acanthosphere-like Li4Ti5O12 microspheres and their excellent performance as an anode in LIBs were also discussed in this work.

MesoDyn simulation study on the phase morphologies of Miktoarm PEO-b-PMMA copolymer doped by nanoparticles

Science.gov (United States)

Mu, Dan; Li, Jian-Quan; Feng, Sheng-Yu

2013-03-01

The compatibility of six groups of 12 miktoarm poly(ethylene oxide)-block-poly(methyl methacrylate) (PEO-b-PMMA) copolymers is studied at 270, 298 and 400 K via mesoscopic modeling. The values of the order parameters depend on both the architectures of the block copolymers and the simulation temperature, while the tendency to change of the order parameters at low temperature, such as 270 and 298 K, is nearly the same. However, the values of order parameters of the copolymer in the same group are the same at high temperature, i.e. 400 K. Obviously, temperature has a more obvious effect on long and PEO-rich chains. A study of plain copolymers doped with nanoparticles shows that the microscopic phase is influenced by not only the properties of the nanoparticles, such as the size, number and density, but also the composition and architecture of copolymers. Increasing the size and the number of the nanoparticles used as a dopant plays the most significant role on determining the phase morphologies of the copolymers at lower and higher temperature, respectively. In paricular, the 23141 and 23241-type copolymers, which are both of PEO-rich composition, presents microscopic phase separation as perforated lamallae phase morphologies at 400 K, alternated with PEO and PMMA components.

Inkjet-printed gold nanoparticle chemiresistors: Influence of film morphology and ionic strength on the detection of organics dissolved in aqueous solution

International Nuclear Information System (INIS)

Chow, Edith; Herrmann, Jan; Barton, Christopher S.; Raguse, Burkhard; Wieczorek, Lech

2009-01-01

The influence of film morphology on the performance of inkjet-printed gold nanoparticle chemiresistors has been investigated. Nanoparticles deposited from a single-solvent system resulted in a 'coffee ring'-like structure with most of the materials deposited at the edge. It was shown that the uniformity of the film could be improved if the nanoparticles were deposited from a mixture of solvents comprising N-methyl-2-pyrrolidone and water. Electrical conductivity measurements showed that both 'coffee ring' and 'flat' films were qualitatively similar suggesting that the films have similar nanoscale structures. To form the functional chemiresistor device, the 4-(dimethylamino)pyridine coating on the nanoparticle was exchanged with 1-hexanethiol to provide a hydrophobic sensing layer. The performance of 1-hexanethiol coated gold nanoparticle chemiresistors to small organic molecules, toluene, dichloromethane and ethanol dissolved in 1 M KCl in regard to changes in impedance and response times was unaffected by the film morphology. For larger hydrocarbons such as octane, the rate of uptake of the analyte into the film was significantly faster when the flatter nanoparticle film was used as opposed to the 'coffee ring' film which has a thicker edge. Furthermore, the presence of potassium and chloride ions in the solution media does not significantly affect the impedance of the nanoparticle film at 1 Hz (<2% variation in film impedance over more than four orders of magnitude change in ionic strength). However, the ionic strength of the media affected the partitioning of the analyte into the hydrophobic nanoparticle film. The response of the sensor was found to increase with an increased salt concentration due to a salting-out of the analyte from the solution

Gum tragacanth stabilized green gold nanoparticles as cargos for Naringin loading: A morphological investigation through AFM.

Science.gov (United States)

Rao, Komal; Imran, Muhammad; Jabri, Tooba; Ali, Imdad; Perveen, Samina; Shafiullah; Ahmed, Shakil; Shah, Muhammad Raza

2017-10-15

Gold nanoparticles (AuNPs) have attracted greater scientific interests for the construction of drugs loading cargos due to their biocompatibility, safety and facile surface modifications. This study deals with the fabrication of gum tragacanth (GT) green AuNPs as carrier for Naringin, a less water soluble therapeutic molecule. The optimized AuNPs were characterized through UV-vis spectroscopy, FT-IR and atomic force microscope (AFM). Naringin loaded nanoparticles were investigated for their bactericidal potentials using Tetrazolium Microplate assay. Morphological studies conducted via AFM revealed spherical shape for AuNPs with nano-range size and stabilized by GT multi-functional groups. The AuNPs acted as carrier for increased amount of Naringin. Upon loading in AuNPs, Naringin An increased in the bactericidal potentials of Naringin was observed after loading on AuNPs against various tested bacterial strains. This was further authenticated by the surface morphological analysis, showing enhanced membrane destabilizing effects of loaded Naringin. The results suggest that GT stabilized green AuNPs can act as effective delivery vehicles for enhancing bactericidal potentials of Naringin. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hierarchical Mesoporous Lithium-Rich Li[Li0.2Ni0.2Mn0.6]O2 Cathode Material Synthesized via Ice Templating for Lithium-Ion Battery.

Science.gov (United States)

Li, Yu; Wu, Chuan; Bai, Ying; Liu, Lu; Wang, Hui; Wu, Feng; Zhang, Na; Zou, Yufeng

2016-07-27

Tuning hierarchical micro/nanostructure of electrode materials is a sought-after means to reinforce their electrochemical performance in the energy storage field. Herein, we introduce a type of hierarchical mesoporous Li[Li0.2Ni0.2Mn0.6]O2 microsphere composed of nanoparticles synthesized via an ice templating combined coprecipitation strategy. It is a low-cost, eco-friendly, and easily operated method using ice as a template to control material with homogeneous morphology and rich porous channels. The as-prepared material exhibits remarkably enhanced electrochemical performances with higher capacity, more excellent cycling stability and more superior rate property, compared with the sample prepared by conventional coprecipitation method. It has satisfactory initial discharge capacities of 280.1 mAh g(-1) at 0.1 C, 207.1 mAh g(-1) at 2 C, and 152.4 mAh g(-1) at 5 C, as well as good cycle performance. The enhanced electrochemical performance can be ascribed to the stable hierarchical microsized structure and the improved lithium-ion diffusion kinetics from the highly porous structure.

Hierarchical structured graphene/metal oxide/porous carbon composites as anode materials for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Guo, Rong [Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875 (China); Yue, Wenbo, E-mail: wbyue@bnu.edu.cn [Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875 (China); Ren, Yu [National Institute of Clean-and-Low-Carbon Energy, Beijing 102209 (China); Zhou, Wuzong [School of Chemistry, University of St. Andrews, St. Andrews, Fite KY16 9ST (United Kingdom)

2016-01-15

Highlights: • CeO{sub 2} and Co{sub 3}O{sub 4} nanoparticles display different behavior within CMK-3. • CMK-3-CeO{sub 2} and Co{sub 3}O{sub 4} show various electrochemical properties • CMK-3-CeO{sub 2} and Co{sub 3}O{sub 4} are further wrapped by graphene nanosheets. • Graphene-encapsulated composites show better electrochemical performances. - Abstract: As a novel anode material for lithium-ion batteries, CeO{sub 2} displays imperceptible volumetric and morphological changes during the lithium insertion and extraction processes, and thereby exhibits good cycling stability. However, the low theoretical capacity and poor electronic conductivity of CeO{sub 2} hinder its practical application. In contrast, Co{sub 3}O{sub 4} possesses high theoretical capacity, but undergoes huge volume change during cycling. To overcome these issues, CeO{sub 2} and Co{sub 3}O{sub 4} nanoparticles are formed inside the pores of CMK-3 and display various electrochemical behaviors due to the different morphological structures of CeO{sub 2} and Co{sub 3}O{sub 4} within CMK-3. Moreover, the graphene/metal oxide/CMK-3 composites with a hierarchical structure are then prepared and exhibit better electrochemical performances than metal oxides with or without CMK-3. This novel synthesis strategy is hopefully employed in the electrode materials design for Li-ion batteries or other energy conversion and storage devices.

Hierarchical carbon nanostructure design: ultra-long carbon nanofibers decorated with carbon nanotubes

International Nuclear Information System (INIS)

El Mel, A A; Achour, A; Gautron, E; Angleraud, B; Granier, A; Le Brizoual, L; Djouadi, M A; Tessier, P Y; Xu, W; Choi, C H

2011-01-01

Hierarchical carbon nanostructures based on ultra-long carbon nanofibers (CNF) decorated with carbon nanotubes (CNT) have been prepared using plasma processes. The nickel/carbon composite nanofibers, used as a support for the growth of CNT, were deposited on nanopatterned silicon substrate by a hybrid plasma process, combining magnetron sputtering and plasma-enhanced chemical vapor deposition (PECVD). Transmission electron microscopy revealed the presence of spherical nanoparticles randomly dispersed within the carbon nanofibers. The nickel nanoparticles have been used as a catalyst to initiate the growth of CNT by PECVD at 600 deg. C. After the growth of CNT onto the ultra-long CNF, SEM imaging revealed the formation of hierarchical carbon nanostructures which consist of CNF sheathed with CNTs. Furthermore, we demonstrate that reducing the growth temperature of CNT to less than 500 deg. C leads to the formation of carbon nanowalls on the CNF instead of CNT. This simple fabrication method allows an easy preparation of hierarchical carbon nanostructures over a large surface area, as well as a simple manipulation of such material in order to integrate it into nanodevices.

Morphology-controlled synthesis of CdWO4 nanorods and nanoparticles via a molten salt method

International Nuclear Information System (INIS)

Wang Yonggang; Ma Junfeng; Tao Jiantao; Zhu Xiaoyi; Zhou Jun; Zhao Zhongqiang; Xie Lijin; Tian Hua

2006-01-01

Cadmium tungstate (CdWO 4 ) nanoparticles and nanorods have been successfully synthesized by a molten salt method at 270 deg. C, and the morphology of the nanocrystals can be controlled by adjusting such reaction conditions as the calcined time and the weight ratio of the salt to the CdWO 4 precursor. The resultant sample is a pure phase of CdWO 4 without any other impurities

Chemical and morphological gradient scaffolds to mimic hierarchically complex tissues: From theoretical modeling to their fabrication.

Science.gov (United States)

Marrella, Alessandra; Aiello, Maurizio; Quarto, Rodolfo; Scaglione, Silvia

2016-10-01

Porous multiphase scaffolds have been proposed in different tissue engineering applications because of their potential to artificially recreate the heterogeneous structure of hierarchically complex tissues. Recently, graded scaffolds have been also realized, offering a continuum at the interface among different phases for an enhanced structural stability of the scaffold. However, their internal architecture is often obtained empirically and the architectural parameters rarely predetermined. The aim of this work is to offer a theoretical model as tool for the design and fabrication of functional and structural complex graded scaffolds with predicted morphological and chemical features, to overcome the time-consuming trial and error experimental method. This developed mathematical model uses laws of motions, Stokes equations, and viscosity laws to describe the dependence between centrifugation speed and fiber/particles sedimentation velocity over time, which finally affects the fiber packing, and thus the total porosity of the 3D scaffolds. The efficacy of the theoretical model was tested by realizing engineered graded grafts for osteochondral tissue engineering applications. The procedure, based on combined centrifugation and freeze-drying technique, was applied on both polycaprolactone (PCL) and collagen-type-I (COL) to test the versatility of the entire process. A functional gradient was combined to the morphological one by adding hydroxyapatite (HA) powders, to mimic the bone mineral phase. Results show that 3D bioactive morphologically and chemically graded grafts can be properly designed and realized in agreement with the theoretical model. Biotechnol. Bioeng. 2016;113: 2286-2297. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Graphene oxide reinforced core-shell structured Ag@Cu2O with tunable hierarchical morphologies and their morphology-dependent electrocatalytic properties for bio-sensing applications.

Science.gov (United States)

Gan, Tian; Wang, Zhikai; Shi, Zhaoxia; Zheng, Dongyun; Sun, Junyong; Liu, Yanming

2018-07-30

In this study, a facile solution approach was developed for the synthesis of a series of core-shell structured Ag@Cu 2 O nanocrystals of various shapes including triangles, spheres, and cubes with well-defined stable heterojunctions. The electrooxidation of dopamine (DA), uric acid (UA), guanine (G), and adenine (A) using these hybrids revealed morphology-dependent sensing properties, with activities and accumulation ability following the order, triangular Ag@Cu 2 O > spherical Ag@Cu 2 O > cubic Ag@Cu 2 O. Further, we constructed a novel graphene oxide (GO) nanosheet-reinforced triangular Ag@Cu 2 O ternary hetero-nanostructure. Such a hybrid with a three-dimensional interconnected hierarchical architecture is suitable for catalysis, since it not only leads to improved interfacial electron transfer, but also readily exposes the highly catalytic Ag@Cu 2 O to the reactants. Therefore, more enhanced electrochemical activities were observed for the oxidation of DA, UA, G, and A. This study provides an efficient way to synthesize morphology-controlled Ag@Cu 2 O heterogeneous catalysts for the fabrication of potential biosensors, and also opens up attractive avenues in the design of multifunctional ternary noble metal-semiconductor-carbon hybrids. Copyright © 2018 Elsevier B.V. All rights reserved.

Bio-derived three-dimensional hierarchical carbon-graphene-TiO2 as electrode for supercapacitors.

Science.gov (United States)

Jiang, Lili; Ren, Zhifeng; Chen, Shuo; Zhang, Qinyong; Lu, Xiong; Zhang, Hongping; Wan, Guojiang

2018-03-13

This paper reports a novel loofah-derived hierarchical scaffold to obtain three-dimensional biocarbon-graphene-TiO 2 (BC-G-TiO 2 ) composite materials as electrodes for supercapacitors. The loofah scaffold was first loaded with G and TiO 2 by immersing, squeezing, and loosening into the mixed solution of graphene oxide and titania, and then carbonized at 900 °C to form the BC-G-TiO 2 composite. The synergistic effects of the naturally hierarchical biocarbon structure, graphene, and TiO 2 nanoparticles on the electrochemical properties are analyzed. The biocarbon provides a high interconnection and an easy accessibility surface for the electrolyte. Graphene bridged the BC and TiO 2 nanoparticles, improved the conductivity of the BC-G-TiO 2 composite, and increased the electron transfer efficiency. TiO 2 nanoparticles also contributed to the pesudocapacitance and electrochemical stability.

The effects of cerium doping on the size, morphology, and optical properties of α-hematite nanoparticles for ultraviolet filtration

Energy Technology Data Exchange (ETDEWEB)

Cardillo, Dean [Institute for Superconducting and Electronic Materials, AIIM Facility, University of Wollongong Innovation Campus, Squires Way, North Wollongong, NSW 2500 (Australia); Konstantinov, Konstantin, E-mail: konstan@uow.edu.au [Institute for Superconducting and Electronic Materials, AIIM Facility, University of Wollongong Innovation Campus, Squires Way, North Wollongong, NSW 2500 (Australia); Devers, Thierry [Centre de Recherche sur la Matière Divisée, Institut de Physique, site de Chartres, Université d’Orléans (France)

2013-11-15

Highlights: • Possible application of cerium-doped α-hematite as ultraviolet filter. • Nanoparticles obtained through co-precipitation technique using various cerium doping levels followed by annealing. • Comprehensive materials characterisation utilizing XRD, DSC/TGA, STEM, UV–vis spectroscopy. • Increasing cerium content reduces particle sizing and alters morphology. • Solubility of cerium in hematite seen between 5 and 10% doping, 10% cerium doping greatly enhances attenuation in ultraviolet region and increases optical bandgap. - Abstract: Metal oxide nanoparticles have potential use in energy storage, electrode materials, as catalysts and in the emerging field of nanomedicine. Being able to accurately tailor the desirable properties of these nanoceramic materials, such as particle size, morphology and optical bandgap (E{sub g}) is integral in the feasibility of their use. In this study we investigate the altering of both the structure and physical properties through the doping of hematite (α-Fe{sub 2}O{sub 3}) nanocrystals with cerium at a range of concentrations, synthesised using a one-pot co-precipitation method. This extremely simple synthesis followed by thermal treatment results in stable Fe{sub 2−x}Ce{sub x}O{sub y} nanoceramics resulting from the burning of any unreacted precursors and transformation of goethite-cerium doped nanoparticle intermediate. The inclusion of Ce into the crystal lattice of these α-Fe{sub 2}O{sub 3} nanoparticles causes a significantly large reduction in mean crystalline size and alteration in particle morphology with increasing cerium content. Finally we report an increase optical semiconductor bandgap, along with a substantial increase in the ultraviolet attenuation found for a 10% Ce-doping concentration which shows the potential application of cerium-doped hematite nanocrystals to be used as a pigmented ultraviolet filter for cosmetic products.

Copper Salts Mediated Morphological Transformation of Cu2O from Cubes to Hierarchical Flower-like or Microspheres and Their Supercapacitors Performances

Science.gov (United States)

Chen, Liang; Zhang, Yu; Zhu, Pengli; Zhou, Fengrui; Zeng, Wenjin; Lu, Daoqiang Daniel; Sun, Rong; Wong, Chingping

2015-01-01

Monodisperse Cu2O of different microstructures, such as cubes, flower-like, and microspheres, have been extensively synthesized by a simple polyol reduction method using different copper salts, i.e. (Cu(acac)2, Cu(OH)2, and Cu(Ac)2·H2O). The effects of copper salts on the morphology of Cu2O were investigated in details through various characterization methods, including X-ray diffraction, transmission electron microscopy, scanning electron microscopy and UV-Vis absorption spectra. The effects of morphology on the electrochemical properties were further studied. Among the different structures, Cu2O with the microspheric morphology shows the highest specific capacitance and the best cycling stability compared with those of the other two structures, thus bear larger volume charge during the electrochemical reaction due to the microspheres of small nanoparticles. PMID:25857362

Inorganic Nanoparticle Induced Morphological Transition for Confined Self-Assembly of Block Copolymers within Emulsion Droplets.

Science.gov (United States)

Zhang, Yan; He, Yun; Yan, Nan; Zhu, Yutian; Hu, Yuexin

2017-09-07

Recently, it has been reported that the incorporation of functional inorganic nanoparticles (NPs) into the three-dimensional (3D) confined self-assembly of block copolymers (BCPs) creates the unique nanostructured hybrid composites, which can not only introduce new functions to BCPs but also induce some interesting morphological transitions of BCPs. In the current study, we systematically investigate the cooperative self-assembly of a series of size-controlled and surface chemistry-tunable gold nanoparticles (AuNPs) and polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) diblock copolymer within the emulsion droplets. The influences of the size, content, and surface chemistry of the AuNPs on the coassembled nanostructures as well as the spatial distribution of AuNPs in the hybrid particles are examined. It is found that the size and content of the AuNPs are related to the entropic interaction, while the surface chemistry of AuNPs is related to the enthalpic interaction, which can be utilized to tailor the self-assembled morphologies of block copolymer confined in the emulsion droplets. As the content of PS-coated AuNPs increases, the morphology of the resulting AuNPs/PS-b-P2VP hybrid particles changes from the pupa-like particles to the bud-like particles and then to the onion-like particles. However, a unique morphological transition from the pupa-like particles to the mushroom-like particles is observed as the content of P4VP-coated AuNPs increases. More interestingly, it is observed that the large AuNPs are expelled to the surface of the BCP particles to reduce the loss in the conformational entropy of the block segment, which can arrange into the strings of necklaces on the surfaces of the hybrid particles.

Morphological features of electrodeposited Pt nanoparticles and its application as anode catalysts in polymer electrolyte formic acid fuel cells

Energy Technology Data Exchange (ETDEWEB)

Jeon, Hongrae; Joo, Jiyong; Kwon, Youngkook [Electrochemical Reaction and Technology Laboratory (ERTL), Department of Environmental Science and Engineering, GIST, Gwangju 500-712 (Korea); Uhm, Sunghyun [Ertl Center for Electrochemistry and Catalysis, GIST, Gwangju 500-712 (Korea); Lee, Jaeyoung [Electrochemical Reaction and Technology Laboratory (ERTL), Department of Environmental Science and Engineering, GIST, Gwangju 500-712 (Korea); Ertl Center for Electrochemistry and Catalysis, GIST, Gwangju 500-712 (Korea)

2010-09-15

Electrodeposited Pt nanoparticles on carbon substrate show various morphologies depending on the applied potentials. Dendritic, pyramidal, cauliflower-like, and hemi-spherical morphologies of Pt are formed at potential ranges between -0.2 and 0.3 V (vs. Ag/AgCl) and its particle sizes are distributed from 8 to 26 nm. Dendritic bulky particles over 20 nm are formed at an applied potential of -0.2 V, while low deposition potential of 0.2 V causes dense hemi-spherical structure of Pt less than 10 nm. The influence of different Pt shapes on an electrocatalytic oxidation of formic acid is represented. Consequently, homogeneous distribution of Pt nanoparticles with average particle of ca. 14 nm on carbon paper results in a high surface to volume ratio and the better power performance in a fuel cell application. (author)

Morphology evolution of hierarchical ZnO nanostructures modulated by supersaturation and growth temperature

Science.gov (United States)

Yan, Youguo; Zhou, Lixia; Yu, Lianqing; Zhang, Ye

2008-07-01

Three kinds of ZnO hierarchical structures, nanocombs with tube- and needle-shaped teeth and hierarchical nanorod arrays, were successfully synthesized through the chemical vapor deposition method. Combining the experimental parameters, the microcosmic growing conditions (growth temperature and supersaturation) along the flux was discussed at length, and, based on the conclusions, three reasonable growth processes were proposed. The results and discussions were beneficial to further realize the relation between the growing behavior of the nanomaterial and microcosmic conditions, and the hierarchical nanostructures obtained were also expected to have potential applications as functional blocks in future nanodevices. Furthermore, the study of photoluminescence further indicated that the physical properties were strongly dependent on the crystal structure.

Green synthesis of silver nanoparticles using green tea leaves: Experimental study on the morphological, rheological and antibacterial behaviour

Science.gov (United States)

Nakhjavani, Maryam; Nikkhah, V.; Sarafraz, M. M.; Shoja, Saeed; Sarafraz, Marzieh

2017-10-01

In this paper, silver nanoparticles are produced via green synthesis method using green tea leaves. The introduced method is cost-effective and available, which provides condition to manipulate and control the average nanoparticle size. The produced particles were characterized using x-ray diffraction, scanning electron microscopic images, UV visualization, digital light scattering, zeta potential measurement and thermal conductivity measurement. Results demonstrated that the produced samples of silver nanoparticles are pure in structure (based on the x-ray diffraction test), almost identical in terms of morphology (spherical and to some extent cubic) and show longer stability when dispersed in deionized water. The UV-visualization showed a peak in 450 nm, which is in accordance with the previous studies reported in the literature. Results also showed that small particles have higher thermal and antimicrobial performance. As green tea leaves are used for extracting the silver nanoparticles, the method is eco-friendly. The thermal behaviour of silver nanoparticle was also analysed by dispersing the nanoparticles inside the deionized water. Results showed that thermal conductivity of the silver nano-fluid is higher than that of obtained for the deionized water. Activity of Ag nanoparticles against some bacteria was also examined to find the suitable antibacterial application for the produced particles.

Inkjet-printed gold nanoparticle chemiresistors: Influence of film morphology and ionic strength on the detection of organics dissolved in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Chow, Edith [CSIRO Materials Science and Engineering, PO Box 218, Lindfield, NSW 2070 (Australia)], E-mail: Edith.Chow@csiro.au; Herrmann, Jan; Barton, Christopher S.; Raguse, Burkhard; Wieczorek, Lech [CSIRO Materials Science and Engineering, PO Box 218, Lindfield, NSW 2070 (Australia)

2009-01-19

The influence of film morphology on the performance of inkjet-printed gold nanoparticle chemiresistors has been investigated. Nanoparticles deposited from a single-solvent system resulted in a 'coffee ring'-like structure with most of the materials deposited at the edge. It was shown that the uniformity of the film could be improved if the nanoparticles were deposited from a mixture of solvents comprising N-methyl-2-pyrrolidone and water. Electrical conductivity measurements showed that both 'coffee ring' and 'flat' films were qualitatively similar suggesting that the films have similar nanoscale structures. To form the functional chemiresistor device, the 4-(dimethylamino)pyridine coating on the nanoparticle was exchanged with 1-hexanethiol to provide a hydrophobic sensing layer. The performance of 1-hexanethiol coated gold nanoparticle chemiresistors to small organic molecules, toluene, dichloromethane and ethanol dissolved in 1 M KCl in regard to changes in impedance and response times was unaffected by the film morphology. For larger hydrocarbons such as octane, the rate of uptake of the analyte into the film was significantly faster when the flatter nanoparticle film was used as opposed to the 'coffee ring' film which has a thicker edge. Furthermore, the presence of potassium and chloride ions in the solution media does not significantly affect the impedance of the nanoparticle film at 1 Hz (<2% variation in film impedance over more than four orders of magnitude change in ionic strength). However, the ionic strength of the media affected the partitioning of the analyte into the hydrophobic nanoparticle film. The response of the sensor was found to increase with an increased salt concentration due to a salting-out of the analyte from the solution.

Pd@Pt Core–Shell Nanoparticles with Branched Dandelion-like Morphology as Highly Efficient Catalysts for Olefin Reduction

Science.gov (United States)

A facile synthesis based on the addition of ascorbic acid to a mixture of Na2PdCl4, K2PtCl6, and Pluronic P123 results in highly branched core–shell nanoparticles (NPs) with a micro–mesoporous dandelion-like morphology comprising Pd core and Pt shell. The slow reduction kinetics ...

Investigations of cations distributions and morphology of cobalt ferrite magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Chandekar, Kamlesh V., E-mail: chandekar.kamlex@gmail.com; Kant, K. Mohan [Dept. of Applied Physics, Visvesvaraya National Institute of Technology, Nagpur, - 440010 (India)

2016-05-06

Cobalt ferrite nanoparticles were synthesized by co-precipitation method and structural properties was investigated by X-ray diffraction (XRD) at room temperature. X-ray diffraction data was used to determine lattice parameter, X-ray density, distributions of cations among tetrahedral and octahedral sites, site radii, ionic radii and bond length of inverse spinel cobalt ferrite. XRD analysis revealed crystallinity and high intense peak correspond to cubic inverse spinel structure with average crystalline size measured by X-ray line profile fitting was found to be 13nm for most intense peak (311). The surface morphology and microstructural feature was investigated by TEM analysis which revealed that particle size varying from 12-22 nm with selected electron diffraction pattern (SAED).

Near-Infrared Trigged Stimulus-Responsive Photonic Crystals with Hierarchical Structures.

Science.gov (United States)

Lu, Tao; Pan, Hui; Ma, Jun; Li, Yao; Zhu, Shenmin; Zhang, Di

2017-10-04

Stimuli-responsive photonic crystals (PCs) trigged by light would provide a novel intuitive and quantitative method for noninvasive detection. Inspired by the flame-detecting aptitude of fire beetles and the hierarchical photonic structures of butterfly wings, we herein developed near-infrared stimuli-responsive PCs through coupling photothermal Fe 3 O 4 nanoparticles with thermoresponsive poly(N-isopropylacrylamide) (PNIPAM), with hierarchical photonic structured butterfly wing scales as the template. The nanoparticles within 10 s transferred near-infrared radiation into heat that triggered the phase transition of PNIPAM; this almost immediately posed an anticipated effect on the PNIPAM refractive index and resulted in a composite spectrum change of ∼26 nm, leading to the direct visual readout. It is noteworthy that the whole process is durable and stable mainly owing to the chemical bonding formed between PNIPAM and the biotemplate. We envision that this biologically inspired approach could be utilized in a broad range of applications and would have a great impact on various monitoring processes and medical sensing.

Nanoparticles and self-organisation: the emergence of hierarchical properties from the nanoparticle soup (i.e., the small is getting bigger). Concluding remarks for Faraday Discussion: Nanoparticle Synthesis and Assembly.

Science.gov (United States)

Schiffrin, David J

2015-01-01

Some four years ago, one of the participants in this Discussion (Prof. Nicholas Kotov) predicted that: "within five years we shall see multiple examples of electronic, sensor, optical and other devices utilizing self-assembled superstructures" (N. A. Kotov, J. Mater. Chem., 2011, 21, 16673-16674). Although this prediction came partially to fruition, we have witnessed an unprecedented interest in the properties of materials at the nanoscale. The point highlighted by Kotov, however, was the importance of self-assembly of structures from well characterised building blocks to yield hierarchical structures, hopefully with predictable properties, a concept that is an everyday pursuit of synthetic chemists. This Discussion has brought together researchers from a wide range of disciplines, i.e., colloid science, modelling, nanoparticle synthesis and organisation, magnetic and optical materials, and new imaging methods, within the excellent traditional Faraday Discussion format, to discuss advances in areas relevant to the main theme of the meeting.

Effect of natural extracts pH on morphological characteristics of hybrid materials based on gold nanoparticles

Science.gov (United States)

Olenic, L.; Vulcu, A.; Chiorean, I.; Crisan, M.; Berghian-Grosan, C.; Dreve, S.; David, L.; Tudoran, L. B.; Kacso, I.; Bratu, I.; Neamtu, C.; Voica, C.

2013-11-01

In the present paper we have investigated the pH influence on the morphology of some new hybrid materials based on gold nanoparticles and natural extracts from fruits of Romanian native plants of Adoxaceae family (Viburnum opulus L. and Sambucus nigra L.). It is well known that the natural plants extracts are beneficial for humans thanks to their antioxidant, anti-inflammatory and immunomodulatory effects. The biological activity of these berries is mainly due to their high content of anthocyanins and other polyphenols. The nanoparticles facilitate the penetration of substances in skin, enhancing their antimitotic, anti-inflammatory and antibiotic properties. We have chosen the optimal method to get these materials in which gold nanoparticles of 10-80 nm were obtained. We characterized them by UV-Vis and FT-IR spectroscopy, by TEM and DSC. Creams prepared with the hybrid materials have been tested on psoriatic lesions and the medical results emphasized a remarkable improvement in this diseases.

MnS spheres: Shape-controlled synthesis and its magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Qi, Kezhen [Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, 110034 (China); Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin, 300071 (China); State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070 (China); Wang, Yan-Qin, E-mail: wangyanqin@tyut.edu.cn [Shanxi Key Lab. of Material Strength & Structural Impact, College of Mechanics, Taiyuan University of Technology, Taiyuan, 030024 (China); Rengaraj, Selvaraj, E-mail: srengaraj1971@yahoo.com [Department of Chemistry, College of Science, Sultan Qaboos University, Muscat, 123 (Oman); Al Wahaibi, Bushra [Department of Chemistry, College of Science, Sultan Qaboos University, Muscat, 123 (Oman); Mohamed Jahangir, A.R. [Biyaq Oil Field Services LLC, Mina Al Fahal, Muscat, 123 (Oman)

2017-06-01

Sphere-like MnS hierarchical microstructures were successfully synthesized by a simple hydrothermal approach, which are composed of the size tunable and self-assembled nanoparticles. These hierarchical microspheres are γ-MnS phase, which is confirmed by X-ray diffraction (XRD) results, and the stoichiometry of MnS microspheres is checked by XPS measurement. Morphological studies performed by scanning electron microscopy (SEM) method show that the as-prepared γ-MnS samples are hierarchical microspheres. The size and morphology of composed nanoparticles can be turned by the concentration of L-Cystein molecules. Here, L-Cystein not only plays a role of sulfur source but also capping agent. Furthermore, a rational mechanism about the formation and evolution of the products is proposed. The present work shows that the origin of the observed difference of magnetic properties is due to the morphology difference of MnS crystals. - Highlights: • Sphere-like MnS hierarchical microstructures were synthesized and characterized. • The size and morphology of MnS crystals can be turned by the concentration of L-Cystein molecules. • The morphology of MnS hierarchitectures exerts a remarkable effect on their magnetic property.

Electrodeposition of hierarchical ZnO nanorod arrays on flexible stainless steel mesh for dye-sensitized solar cell

Energy Technology Data Exchange (ETDEWEB)

Lu, Hui; Zhai, Xiangyang; Liu, Wenwu; Zhang, Mei; Guo, Min, E-mail: guomin@ustb.edu.cn

2015-07-01

Hierarchical ZnO nanorod arrays (ZNRAs) were synthesized on flexible stainless steel mesh (SSM) in large scale by a two-step facile electrodeposition method. The structure and morphology of the as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The growth mechanism of the ZnO hierarchical nanostructures was also discussed. Moreover, the effect of ZnO morphology on the photovoltaic performance of the flexible DSSCs based on SSM supported ZnO nanostructures was investigated in detail. It is shown that the flexible DSSCs exhibited a relatively higher power conversion efficiency of 1.11% compared with that based on primary ZNRAs. - Highlights: • Hierarchical ZnO nanorod arrays (ZNRAs) were prepared by electrodeposition method. • Flexible stainless steel mesh (SSM) supported with hierarchical ZNRAs was first used for DSSCs. • The effect of ZnO morphology on the photovoltaic performance of flexible DSSCs was investigated. • The DSSC based on 3-Hierarchical ZNRAs/ZNPs showed a relatively efficiency of 1.11%.

Effects of ionic surfactants on the morphology of silver nanoparticles using Paan (Piper betel) leaf petiole extract.

Science.gov (United States)

Khan, Zaheer; Bashir, Ommer; Hussain, Javed Ijaz; Kumar, Sunil; Ahmad, Rabia

2012-10-01

Stable silver nanoparticles were synthesized by the reduction of silver ions with a Paan (Piper betel) leaf petiole extract in absence and presence of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulphate (SDS). The reaction process was simple and convenient to handle, and was monitored using ultraviolet-visible spectroscopy. Absorbance of Ag-nanoparticles increases with the concentrations of Paan leaf extract, acts as reducing, stabilizing and capping agents. The polyphenolic groups of petiole extract are responsible to the rapid reduction of Ag(+) ions into metallic Ag(0). The results indicated that the shape of the spectra, number of peaks and its position strongly depend on the concentration of CTAB, which played a shape-controlling role during the formation of silver nanoparticles in the solutions, whereas SDS has no significant effect. The morphology (spherical, truncated triangular polyhedral plate and some irregular nanoparticles) and crystalline phase of the particles were determined from transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Copyright © 2012 Elsevier B.V. All rights reserved.

Impact of Amorphous Silica Nanoparticles on a Living Organism: Morphological, Behavioural and Molecular Biology Implications.

Directory of Open Access Journals (Sweden)

Alfredo eAmbrosone

2014-09-01

Full Text Available It is generally accepted that silica (SiO2 is not toxic. But the increasing use of silica nanoparticles (SiO2NPs in many different industrial fields has prompted the careful investigation of its toxicity in biological systems. In this report, we describe the effects elicited by SiO2NPs on animal and cell physiology. Stable and monodisperse amorphous silica nanoparticles 25nm in diameter, were administered to living Hydra vulgaris (Cnidaria. The dose-related effects were defined by morphological and behavioural assays. The results revealed an all-or-nothing lethal toxicity with a rather high threshold (35nM NPs and a LT50 of 38h. At sub lethal doses the morpho-physiological effects included: animal morphology alterations, paralysis of the gastric region, disorganization and depletion of tentacle specialized cells, increase of apoptotic and collapsed cells and reduction of the epithelial cell proliferation rate. Transcriptome analysis (RNAseq revealed 45 differentially expressed genes, mostly involved in stress response and cuticle renovation. Our results show that Hydra reacts to SiO2NPs, is able to rebalance the animal homeostasis up to a relatively high doses of SiO2NPs and that the physiological modifications are transduced to gene expression modulation.

Wet-Chemical Preparation of TiO2-Based Composites with Different Morphologies and Photocatalytic Properties

Directory of Open Access Journals (Sweden)

Liqin Xiang

2017-10-01

Full Text Available TiO2-based composites have been paid significant attention in the photocatalysis field. The size, crystallinity and nanomorphology of TiO2 materials have an important effect on the photocatalytic efficiency. The synthesis and photocatalytic activity of TiO2-based materials have been widely investigated in past decades. Based on our group’s research works on TiO2 materials, this review introduces several methods for the fabrication of TiO2, rare-earth-doped TiO2 and noble-metal-decorated TiO2 particles with different morphologies. We focused on the preparation and the formation mechanism of TiO2-based materials with unique structures including spheres, hollow spheres, porous spheres, hollow porous spheres and urchin-like spheres. The photocatalytical activity of urchin-like TiO2, noble metal nanoparticle-decorated 3D (three-dimensional urchin-like TiO2 and bimetallic core/shell nanoparticle-decorated urchin-like hierarchical TiO2 are briefly discussed.

Investigation of Structural, Morphological, Magnetic Properties and Biomedical applications of Cu2+ Substituted Uncoated Cobalt Ferrite Nanoparticles

Directory of Open Access Journals (Sweden)

M. Margabandhu

Full Text Available ABSTRACT In the present work, Cu2+ substituted cobalt ferrite (Co1-xCuxFe2O4, x = 0, 0.3, 0.5, 0.7 and 1 magnetic nanopowders were synthesized via chemical co-precipitation method. The prepared powders were investigated by various characterization methods such as X-ray diffraction analysis (XRD, scanning electron microscope analysis (SEM, vibrating sample magnetometer analysis (VSM and fourier transform infrared spectroscopy analysis (FTIR. The XRD analysis reveals that the synthesized nanopowders possess single phase centred cubic spinel structure. The average crystallite size of the particles ranging from 27-49 nm was calculated by using Debye-scherrer formula. Magnetic properties of the synthesized magnetic nanoparticles are studied by using VSM. The VSM results shows the magnetic properties such as coercivity, magnetic retentivity decreases with increase in copper substitution whereas the saturation magnetization shows increment and decrement in accordance with Cu2+ substitution in cobalt ferrite nanoparticles. SEM analysis reveals the morphology of synthesized magnetic nanoparticles. FTIR spectra of Cu2+ substituted cobalt ferrite magnetic nanoparticles were recorded in the frequency range 4000-400cm-1. The spectrum shows the presence of water adsorption and metal oxygen bonds. The adhesion nature of Cu2+ substituted cobalt ferrite magnetic nanoparticles with bacteria in reviewed results indicates that the synthesized nanoparticles could be used in biotechnology and biomedical applications.

A four-functional composite-hierarchical anatase TiO2 microsphere consisting of nanoparticles, nanowires and submicron ellipsoidal spheres for Dye Sensitized Solar Cells

International Nuclear Information System (INIS)

Huang, Niu; Chen, Feitai; Sun, Panpan; Sun, Xiaohua; Sebo, Bobby; Zhao, Xingzhong

2014-01-01

Graphical abstract: - Abstract: In this paper, we prepare a composite-hierarchical microsphere (HMS) which is composed of two kinds of HMSs: one flower-like microsphere (FMS, ∼1.5 μm, containing nanoparticles and nanowires) and plentiful mesoporous submicron ellipsoidal spheres (ESs, ∼200 nm, assembled with nanoparticles) which are embedded evenly in the FMS. For comparing, pure FMS and ES are prepared, respectively. It is found that the composite-HMS possesses (a) the highest BET surface area, (b) the highest light scattering ability, (c) the fastest electron transport and the longest electron life time, and (d) light trapping ability enabled by multiple light reflection and scattering between ESs and nanowires inside each FMS*ESs particle. The energy conversion efficiency of 7.91% of the DSSC based on FMS*ESs is higher than devices based on ES and FMS (7.22% and 7.24%, respectively), which also benefits from the structural advantages of the composite-HMS compared with non-composite HMSs

TiO2 nanowire-templated hierarchical nanowire network as water-repelling coating

Science.gov (United States)

Hang, Tian; Chen, Hui-Jiuan; Xiao, Shuai; Yang, Chengduan; Chen, Meiwan; Tao, Jun; Shieh, Han-ping; Yang, Bo-ru; Liu, Chuan; Xie, Xi

2017-12-01

Extraordinary water-repelling properties of superhydrophobic surfaces make them novel candidates for a great variety of potential applications. A general approach to achieve superhydrophobicity requires low-energy coating on the surface and roughness on nano- and micrometre scale. However, typical construction of superhydrophobic surfaces with micro-nano structure through top-down fabrication is restricted by sophisticated fabrication techniques and limited choices of substrate materials. Micro-nanoscale topographies templated by conventional microparticles through surface coating may produce large variations in roughness and uncontrollable defects, resulting in poorly controlled surface morphology and wettability. In this work, micro-nanoscale hierarchical nanowire network was fabricated to construct self-cleaning coating using one-dimensional TiO2 nanowires as microscale templates. Hierarchical structure with homogeneous morphology was achieved by branching ZnO nanowires on the TiO2 nanowire backbones through hydrothermal reaction. The hierarchical nanowire network displayed homogeneous micro/nano-topography, in contrast to hierarchical structure templated by traditional microparticles. This hierarchical nanowire network film exhibited high repellency to both water and cell culture medium after functionalization with fluorinated organic molecules. The hierarchical structure templated by TiO2 nanowire coating significantly increased the surface superhydrophobicity compared to vertical ZnO nanowires with nanotopography alone. Our results demonstrated a promising strategy of using nanowires as microscale templates for the rational design of hierarchical coatings with desired superhydrophobicity that can also be applied to various substrate materials.

Effects of Laser Energy Density on Size and Morphology of NiO Nanoparticles Prepared by Pulsed Laser Ablation in Liquid

Energy Technology Data Exchange (ETDEWEB)

Ma, Rory; Reddy, M. Amaranatha; Kim, Tae Kyu [Pusan National University, Busan (Korea, Republic of)

2015-01-15

Metaloxide nanoparticles are of great importance to a large variety of chemical and material applications ranging from catalysts to electronic devices. Among the metal-oxide nanoparticles, NiO is one of the technologically versatile and important semiconducting materials. It has been extensively investigated because of its myriad applications in catalysts, gas sensors, Li-ion battery materials, electrochromic coatings, active optical fibers, fuel cell electrodes, and so on. The effect of laser ablation at various laser energy densities was investigated. At low energy densities, the produced nanoparticles were of irregular morphology with an average size of 2.4 nm. At higher laser energy densities, the produced nanoparticles were spherical, with a polycrystalline structure and their average size was around 10 nm. More detailed investigations on effects of laser wavelength and energy density as well as the particle size effect on the catalytic activity of synthesized NiO nanoparticles will be investigated in future works.

Manufacturing and investigation of surface morphology and optical properties of composite thin films reinforced by TiO2, Bi2O3 and SiO2 nanoparticles

Science.gov (United States)

Jarka, Paweł; Tański, Tomasz; Matysiak, Wiktor; Krzemiński, Łukasz; Hajduk, Barbara; Bilewicz, Marcin

2017-12-01

The aim of submitted paper is to present influence of manufacturing parameters on optical properties and surface morphology of composite materials with a polymer matrix reinforced by TiO2 and SiO2 and Bi2O3 nanoparticles. The novelty proposed by the authors is the use of TiO2 and SiO2 and Bi2O3 nanoparticles simultaneously in polymeric matrix. This allows using the combined effect of nanoparticles to a result composite material. The thin films of composite material were prepared by using spin-coating method with various spinning rates from solutions of different concentration of nanoparticles. In order to prepare the spinning solution polymer, Poly(methyl methacrylate) (PMMA) was used as a matrix. The reinforcing phase was the mixture of the nanoparticles of SiO2, TiO2 and B2O3. In order to identify the surface morphology of using thin films and arrangement of the reinforcing phase Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) were used. In order to study the optical properties of the obtained thin films, the thin films of composites was subjected to an ellipsometry analysis. The measurements of absorbance of the obtained materials, from which the value of the band gap width was specified, were carried out using the UV/VIS spectroscopy. The optical properties of obtain composite thin films depend not only on the individual components used, but also on the morphology and the interfacial characteristics. Controlling the participation of three kinds of nanoparticles of different sizes and optical parameters allows to obtaining the most optimal optical properties of nanocomposites and also controlling the deposition parameters allows to obtaining the most optimal surface morphology of nanocomposites.

Effect of silver nanoparticles' generation routes on the morphology, oxygen, and water transport properties of starch nanocomposite films

Energy Technology Data Exchange (ETDEWEB)

Cheviron, Perrine; Gouanvé, Fabrice, E-mail: fabrice.gouanve@univ-lyon1.fr; Espuche, Eliane, E-mail: eliane.espuche@univ-lyon1.fr [Université de Lyon (France)

2015-09-15

A strategy involving the preparation of silver nanoparticles in a biodegradable polymer stemming from an ex situ or an in situ method using a green chemistry process is reported. The influence of the reducing agent concentration and the silver nanoparticles' generation route were investigated on the structure, the morphology, and the properties of the nanocomposite films. Two distinct silver nanoparticle populations in size were highlighted from the ex situ route (diameter around 5 nm for the first one and from 20 to 50 nm for the second one), whereas one population was highlighted from the in situ route (around 10 nm). No modification on the crystalline structure of the starch matrix was observed in presence of silver. Crystalline silver nanoparticles were obtained only from the in situ generation route. The decrease of the water sorption and the improvement of water and oxygen barrier properties were found to be not dependent on the reducing agent concentration but mainly on the crystalline structure of the silver nanoparticles associated to the presence of strong interface between the silver nanoparticles and the starch polymer matrix.

Hierarchical ZnO with twinned structure: Morphology evolution, formation mechanism and properties

International Nuclear Information System (INIS)

Shi, Ruixia; Song, Xueling; Li, Jia; Yang, Ping

2015-01-01

Various hierarchical ZnO architectures constructed by twinned structures have been synthesized via a trisodium citrate assisted hydrothermal method on a large scale. The probable formation mechanisms of hierarchical ZnO structures with twinned structure were proposed and discussed. The hierarchical ZnO with twinned structures are composed of two hemispheres with a center concave junction to join them together at their waists. The ZnO microspheres with rough surfaces were obtained when the concentration of trisodium citrate is 0.1 M. However, the football-like microspheres consisted of hexagonal nanosheets were formed when adding glycerol into the water, which should be attributed to the slower nucleation and growth rate of nanocrystals. The hamburger-like ZnO with different aspect ratio and nonuniform ZnO microspheres were generated due to the different quantity of initial nuclei and growth units when simply modulating the concentration of trisodium citrate. The surface area of football-like ZnO is about 3.51 times of microspheres composed of irregular particles. However their photocatalytic performances are similar under UV light irradiation, which indicates that pore sizes of the sample have more important influences on the photocatalytic activity. - Highlights: • Hierarchical ZnO constructed by twinned structures have been synthesized. • The formation mechanisms of ZnO with twinned structure were discussed. • Football-like microspheres were obtained due to the slower nucleation and growth. • Hamburger-like ZnO was formed due to the amount of initial nuclei and growth units. • Pore sizes have important effects on the photocatalytic activity of sample

Hierarchical ZnO with twinned structure: Morphology evolution, formation mechanism and properties

Energy Technology Data Exchange (ETDEWEB)

Shi, Ruixia; Song, Xueling; Li, Jia; Yang, Ping, E-mail: mse_yangp@ujn.edu.cn

2015-04-15

Various hierarchical ZnO architectures constructed by twinned structures have been synthesized via a trisodium citrate assisted hydrothermal method on a large scale. The probable formation mechanisms of hierarchical ZnO structures with twinned structure were proposed and discussed. The hierarchical ZnO with twinned structures are composed of two hemispheres with a center concave junction to join them together at their waists. The ZnO microspheres with rough surfaces were obtained when the concentration of trisodium citrate is 0.1 M. However, the football-like microspheres consisted of hexagonal nanosheets were formed when adding glycerol into the water, which should be attributed to the slower nucleation and growth rate of nanocrystals. The hamburger-like ZnO with different aspect ratio and nonuniform ZnO microspheres were generated due to the different quantity of initial nuclei and growth units when simply modulating the concentration of trisodium citrate. The surface area of football-like ZnO is about 3.51 times of microspheres composed of irregular particles. However their photocatalytic performances are similar under UV light irradiation, which indicates that pore sizes of the sample have more important influences on the photocatalytic activity. - Highlights: • Hierarchical ZnO constructed by twinned structures have been synthesized. • The formation mechanisms of ZnO with twinned structure were discussed. • Football-like microspheres were obtained due to the slower nucleation and growth. • Hamburger-like ZnO was formed due to the amount of initial nuclei and growth units. • Pore sizes have important effects on the photocatalytic activity of sample.

Facile preparation of hierarchically porous polymer microspheres for superhydrophobic coating

Science.gov (United States)

Gao, Jiefeng; Wong, Julia Shuk-Ping; Hu, Mingjun; Li, Wan; Li, Robert. K. Y.

2013-12-01

A facile method, i.e., nonsolvent assisted electrospraying, is proposed to fabricate hierarchically porous microspheres. The pore size on the microsphere surface ranges from a few tens to several hundred nanometers. Thermally and nonsolvent induced phase separation as well as breath figure is responsible for the formation of the hierarchical structures with different nano-sized pores. The nonsolvent could not only induce phase separation, but also stabilize the interface between the droplet and air, which can prevent the droplet from strong deformation, and is therefore beneficial to the formation of regular and uniform microspheres. On the other hand, solvent evaporation, polymer diffusion and Coulomb fission during electrospraying influence the morphology of finally obtained products. In this paper, the influence of polymer concentration, the weight ratio between nonsolvent and polymer and the flowing rate on the morphology of the porous microsphere is carefully studied. The hierarchically porous microsphere significantly increases the surface roughness and thus the hydrophobicity, and the contact angle can reach as high as 152.2 +/- 1.2°. This nonsolvent assisted electrospraying opens a new way to fabricate superhydrophobic coating materials.A facile method, i.e., nonsolvent assisted electrospraying, is proposed to fabricate hierarchically porous microspheres. The pore size on the microsphere surface ranges from a few tens to several hundred nanometers. Thermally and nonsolvent induced phase separation as well as breath figure is responsible for the formation of the hierarchical structures with different nano-sized pores. The nonsolvent could not only induce phase separation, but also stabilize the interface between the droplet and air, which can prevent the droplet from strong deformation, and is therefore beneficial to the formation of regular and uniform microspheres. On the other hand, solvent evaporation, polymer diffusion and Coulomb fission during

Cobalt nanoparticles deposited and embedded in AlN: Magnetic, magneto-optical, and morphological properties

International Nuclear Information System (INIS)

Huttel, Y.; Gomez, H.; Clavero, C.; Cebollada, A.; Armelles, G.; Navarro, E.; Ciria, M.; Benito, L.; Arnaudas, J.I.; Kellock, A.J.

2004-01-01

We present a structural, morphological, magnetic, and magneto-optical study of cobalt nanoparticles deposited on 50 A ring AlN/c-sapphire substrates and embedded in an AlN matrix. The dependence of the properties of Co nanoclusters deposited on AlN with growth temperature and amount of deposited Co are studied and discussed. Also we directly compare the properties of as grown and AlN embedded Co nanoclusters and show that the AlN matrix has a strong impact on their magnetic and magneto-optical properties

Morphology-properties relationship on nanocomposite films based on poly(styrene-block-diene-block-styrene copolymers and silver nanoparticles

Directory of Open Access Journals (Sweden)

2011-02-01

Full Text Available A comparative study on the self-assembled nanostructured morphology and the rheological and mechanical properties of four different triblock copolymers, based on poly(styrene-block-diene-block-styrene and poly(styrene-block-diene-block-styrene matrices, and of their respective nanocomposites with 1 wt% silver nanoparticles, is reported in this work. In order to obtain well-dispersed nanoparticles in the block copolymer matrix, dodecanethiol was used as surfactant, showing good affinity with both nanoparticles and the polystyrene phase of the matrices as predicted by the solubility parameters calculated based on Hoftyzer and Van Krevelen theory. The block copolymer with the highest PS content shows the highest tensile modulus and tensile strength, but also the smallest elongation at break. When silver nanoparticles treated with surfactant were added to the block copolymer matrices, each system studied shows higher mechanical properties due to the good dispersion and the good interface of Ag nanoparticles in the matrices. Furthermore, it has been shown that semiempirical models such as Guth and Gold equation and Halpin-Tsai model can be used to predict the tensile modulus of the analyzed nanocomposites.

Controllable hydrothermal synthesis of Ni/H-BEA with a hierarchical core-shell structure and highly enhanced biomass hydrodeoxygenation performance.

Science.gov (United States)

Ma, Bing; Cui, Huimei; Wang, Darui; Wu, Peng; Zhao, Chen

2017-05-11

Ni based catalysts are wildly used in catalytic industrial processes due to their low costs and high activities. The design of highly hierarchical core-shell structured Ni/HBEA is achieved using a sustainable, simple, and easy-tunable hydrothermal synthesis approach using combined NH 4 Cl and NH 3 ·H 2 O as a co-precipitation agent at 120 °C. Starting from a single-crystalline hierarchical H + -exchanged beta polymorph zeolite (HBEA), the adjustment of the precipitate conditions shows that mixed NH 4 Cl and NH 3 ·H 2 O precipitates with proper concentrations are vital in the hydrothermal synthesis for preserving a good crystalline morphology of HBEA and generating abundant highly-dispersed Ni nanoparticles (loading: 41 wt%, 5.9 ± 0.7 nm) encapsulated onto/into the support. NH 4 Cl solution without an alkali is unable to generate abundant Ni nanoparticles from Ni salts under the hydrothermal conditions, whereas NH 3 ·H 2 O seriously damages the pore structure. After studying the in situ changes in infrared, X-ray diffractometry, temperature-programmed reduction, and scanning electron microscopy measurements, as well as variations in the filtrate pH, Si/Al ratios, and solid sample Ni loading, a two-step dissolution-recrystallization process is proposed. The process consists of Si dissolution and no change in elemental Al, and after the dissolved Si(iv) concentrations have promoted Ni phyllosilicate nanosheet solubility, further growth of multilayered Ni phyllosilicate nanosheets commences. The precursor Ni phyllosilicate is changeable between Ni 3 Si 2 O 5 (OH) 4 and Ni 3 Si 4 O 10 (OH) 2 , because of competition in kinetically-favored and thermodynamically-controlled species caused by different basic agents. The superior catalytic performance is demonstrated in the metal/acid catalyzed biomass derived bulky stearic acid hydrodeoxygenation with 90% octadecane selectivity and a promising rate of 54 g g -1 h -1 , which highly excels the reported rates catalyzed by

Humid Heat Autoclaving of Hybrid Nanoparticles Achieved by Decreased Nanoparticle Concentration and Improved Nanoparticle Stability Using Medium Chain Triglycerides as a Modifier.

Science.gov (United States)

Gou, Jingxin; Chao, Yanhui; Liang, Yuheng; Zhang, Ning; He, Haibing; Yin, Tian; Zhang, Yu; Xu, Hui; Tang, Xing

2016-09-01

Humid heat autoclaving is a facile technique widely used in the sterilization of injections, but the high temperature employed would destroy nanoparticles composed of biodegradable polymers. The aim of this study was to investigate whether incorporation of medium chain triglycerides (MCT) could stabilize nanoparticles composed of poly (ethylene glycol)-b-polycaprolactone (PEG-b-PCL) during autoclaving (121°C, 10 min). Polymeric nanoparticles with different MCT contents were prepared by dialysis. Block copolymer degradation was studied by GPC. The critical aggregation concentrations of nanoparticles at different temperatures were determined using pyrene fluorescence. The size, morphology and weight averaged molecular weight of pristine/autoclaved nanoparticles were studied using DLS, TEM and SLS, respectively. Drug loading content and release profile were determined using RP-HPLC. The protecting effect of MCT on nanoparticles was dependent on the amount of MCT incorporated. Nanoparticles with high MCT contents, which assumed an emulsion-like morphology, showed reduced block copolymer degradation and particle disassociation after incubation at 100°C for 24 h. Nanoparticles with high MCT content showed the lowest critical aggregation concentration (CAC) under either room temperature or 60°C and the lowest particle concentration among all samples. And the particle size, drug loading content, physical stability and release profile of nanoparticles with high MCT contents remained nearly unchanged after autoclaving. Incorporation of high amount of MCT changed the morphology of PEG-b-PCL based nanoparticles to an emulsion-like structure and the nanoparticles prepared could withstand autoclaving due to improved particle stability and decreased particle concentration caused by MCT incorporation.

Formic Acid Oxidation over Hierarchical Porous Carbon Containing PtPd Catalysts

Directory of Open Access Journals (Sweden)

Elena Pastor

2013-10-01

Full Text Available The use of high surface monolithic carbon as support for catalysts offers important advantage, such as elimination of the ohmic drop originated in the interparticle contact and improved mass transport by ad-hoc pore design. Moreover, the approach discussed here has the advantage that it allows the synthesis of materials having a multimodal porous size distribution, with each pore size contributing to the desired properties. On the other hand, the monolithic nature of the porous support also imposes new challenges for metal loading. In this work, the use of Hierarchical Porous Carbon (HPC as support for PtPd nanoparticles was explored. Three hierarchical porous carbon samples (denoted as HPC-300, HPC-400 and HPC-500 with main pore size around 300, 400 and 500 nm respectively, are used as porous support. PtPd nanoparticles were loaded by impregnation and subsequent chemical reduction with NaBH4. The resulting material was characterized by EDX, XRD and conventional electrochemical techniques. The catalytic activity toward formic acid and methanol electrooxidation was evaluated by electrochemical methods, and the results compared with commercial carbon supported PtPd. The Hierarchical Porous Carbon support discussed here seems to be promising for use in DFAFC anodes.

Nanoparticles in liquid crystals, and liquid crystals in nanoparticles

Science.gov (United States)

de Pablo, Juan

2015-03-01

Liquid crystals are remarkably sensitive to interfacial interactions. Small perturbations at a liquid crystal interface, for example, can be propagated over relatively long length scales, thereby providing the basis for a wide range of applications that rely on amplification of molecular events into macroscopic observables. Our recent research efforts have focused on the reverse phenomenon; that is, we have sought to manipulate the interfacial assembly of nanoparticles or the organization of surface active molecules by controlling the structure of a liquid crystal. This presentation will consist of a review of the basic principles that are responsible for liquid crystal-mediated interactions, followed by demonstrations of those principles in the context of two types of systems. In the first, a liquid crystal is used to direct the assembly of nanoparticles; through a combination of molecular and continuum models, it is found that minute changes in interfacial energy and particle size lead to liquid-crystal induced attractions that can span multiple orders of magnitude. Theoretical predictions are confirmed by experimental observations, which also suggest that LC-mediated assembly provides an effective means for fabrication of plasmonic devices. In the second type of system, the structure of a liquid crystal is controlled by confinement in submicron droplets. The morphology of the liquid crystal in a drop depends on a delicate balance between bulk and interfacial contributions to the free energy; that balance can be easily perturbed by adsorption of analytes or nanoparticles at the interface, thereby providing the basis for development of hierarchical assembly of responsive, anisotropic materials. Theoretical predictions also indicate that the three-dimensional order of a liquid crystal can be projected onto a two-dimensional interface, and give rise to novel nanostructures that are not found in simple isotropic fluids.

Selective Semihydrogenation of Alkynes Catalyzed by Pd Nanoparticles Immobilized on Heteroatom-Doped Hierarchical Porous Carbon Derived from Bamboo Shoots.

Science.gov (United States)

Ji, Guijie; Duan, Yanan; Zhang, Shaochun; Fei, Benhua; Chen, Xiufang; Yang, Yong

2017-09-11

Highly dispersed palladium nanoparticles (Pd NPs) immobilized on heteroatom-doped hierarchical porous carbon supports (N,O-carbon) with large specific surface areas are synthesized by a wet chemical reduction method. The N,O-carbon derived from naturally abundant bamboo shoots is fabricated by a tandem hydrothermal-carbonization process without assistance of any templates, chemical activation reagents, or exogenous N or O sources in a simple and ecofriendly manner. The prepared Pd/N,O-carbon catalyst shows extremely high activity and excellent chemoselectivity for semihydrogenation of a broad range of alkynes to versatile and valuable alkenes under ambient conditions. The catalyst can be readily recovered for successive reuse with negligible loss in activity and selectivity, and is also applicable for practical gram-scale reactions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of taurine and gold nanoparticles on the morphological and molecular characteristics of muscle development during chicken embryogenesis

DEFF Research Database (Denmark)

Zielinska, Marlena; Sawosz, Ewa; Grodzik, Marta

2012-01-01

The objective of the present investigation was to evaluate the effects of taurine and Au nanoparticles on the expression of genes related to embryonic muscle development and on the morphological characteristics of muscles. Fertilised chicken eggs (n = 160) were randomly divided into four groups......: without injection (Control) and with injection of Au nanoparticles (NanoAu), taurine (Tau) or Au nanoparticles with taurine (NanoAu + Tau). The experimental solutions were given in ovo, on the third day of incubation, by injecting 0.3 ml of the experimental solution into the air sack. The embryos were...... evaluated on the 20th day of incubation. The methods included gene expression at the mRNA and protein levels, immunohistochemistry, histology and microscopy. In groups NanoAu, Tau and NanoAu + Tau, the muscle structure and the number of muscle cells were affected. Furthermore, taurine increased fibre...

Facile synthesis and photocatalytic activity of zinc oxide hierarchical microcrystals

KAUST Repository

Xu, Xinjiang

2013-04-04

ZnO microcrystals with hierarchical structure have been synthesized by a simple solvothermal approach. The microcrystals were studied by means of X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. Research on the formation mechanism of the hierarchical microstructure shows that the coordination solvent and precursor concentration have considerable influence on the size and morphology of the microstructures. A possible formation mechanism of the hierarchical structure was suggested. Furthermore, the catalytic activity of the ZnO microcrystals was studied by treating low concentration Rhodamine B (RhB) solution under UV light, and research results show the hierarchical microstructures of ZnO display high catalytic activity in photocatalysis, the catalysis process follows first-order reaction kinetics, and the apparent rate constant k = 0.03195 min-1.

Directing self-assembly of gold nanoparticles in diblock copolymer scaffold

Science.gov (United States)

Li, Qifang; He, Jinbo; Glogowski, Elizabeth; Emrick, Todd; Russell, Thomas

2007-03-01

A versatile hierarchical approach for directing self -assembly of gold nanostructures with size 2-3nm in diblock copolymer scaffolds is found. Diblock copolymer polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) is used to form a regular scaffold of highly anisotropic, stripe-like domains, and controlled differential wetting by dichloromethane and thermal annealing guides gold nanoparticles with half hydrophilic ligand to aggregate selectively along the scaffold, producing highly organized metal nanostructures. In as-cast block-copolymer and gold nanoparticles thin films, micelle structure and gold nanoparticles random distribution on scaffold are typically observed. However, samples annealed in dichloromethane exhibit well-defined short-range ordered nanostructure with gold nanoparticles located at the interface of PS and P2VP nanoscale domain. After annealing at 170 C, the gold nanoparticles at interface migrated into the middle of P2VP phase and exhibited long-range ordered hierarchical structures. Synergistic interactions between the gold nanoparticles and the PS-b-P2VP caused an orientation of the microdomains normal to the film surface.

Biomimetic synthesis of hierarchical crystalline hydroxyapatite fibers in large-scale

Energy Technology Data Exchange (ETDEWEB)

Xing, Chaogang; Ge, Suxiang; Huang, Baojun; Bo, Yingying [Institute of Surface Micro and Nano Materials, Xuchang University, Xuchang, Henan Province 461000 (China); Zhang, Di [State Key Lab of Metal Matrix Composites, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030 (China); Zheng, Zhi, E-mail: zhengzhi9999@yahoo.com.cn [Institute of Surface Micro and Nano Materials, Xuchang University, Xuchang, Henan Province 461000 (China)

2012-06-15

Highlights: ► Crystalline hierarchical hydroxyapatite (HAp) fibers are synthesized. ► We employ a biomimetic route by using cotton cloth as a natural bio-template. ► We study the effects of pH, ultrasonic cleaning time, and calcination temperature. ► We obtain an optimized reaction condition. ► This is a low cost method for production of hierarchical HAp fibers. -- Abstract: Crystalline hierarchical hydroxyapatite [Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, HAp)] fibers were successfully synthesized via a biomimetic route by using cotton cloth as a natural bio-template. The effects of pH value, aging time, ultrasonic cleaning time, and calcination temperature on the purity and morphology of the resulting hydroxyapatite (HAp) were monitored by scanning election microscope (SEM), X-ray diffraction (XRD), and infrared spectrophotometer (IR) to obtain an optimized reaction condition, namely, pH 9, ultrasonic cleaning for 1 min, aging for 24 h, and calcination at 600 °C for 4 h. We found that the natural cellulose could not only control the morphology of HAp but also lower its phase transformation temperature. The impact of this method lies in its low cost and successful production of large-scale patterning of three-dimensional hierarchical HAp fibers.

Biomimetic synthesis of hierarchical crystalline hydroxyapatite fibers in large-scale

International Nuclear Information System (INIS)

Xing, Chaogang; Ge, Suxiang; Huang, Baojun; Bo, Yingying; Zhang, Di; Zheng, Zhi

2012-01-01

Highlights: ► Crystalline hierarchical hydroxyapatite (HAp) fibers are synthesized. ► We employ a biomimetic route by using cotton cloth as a natural bio-template. ► We study the effects of pH, ultrasonic cleaning time, and calcination temperature. ► We obtain an optimized reaction condition. ► This is a low cost method for production of hierarchical HAp fibers. -- Abstract: Crystalline hierarchical hydroxyapatite [Ca 10 (PO 4 ) 6 (OH) 2 , HAp)] fibers were successfully synthesized via a biomimetic route by using cotton cloth as a natural bio-template. The effects of pH value, aging time, ultrasonic cleaning time, and calcination temperature on the purity and morphology of the resulting hydroxyapatite (HAp) were monitored by scanning election microscope (SEM), X-ray diffraction (XRD), and infrared spectrophotometer (IR) to obtain an optimized reaction condition, namely, pH 9, ultrasonic cleaning for 1 min, aging for 24 h, and calcination at 600 °C for 4 h. We found that the natural cellulose could not only control the morphology of HAp but also lower its phase transformation temperature. The impact of this method lies in its low cost and successful production of large-scale patterning of three-dimensional hierarchical HAp fibers.

A fault diagnosis scheme for planetary gearboxes using adaptive multi-scale morphology filter and modified hierarchical permutation entropy

Science.gov (United States)

Li, Yongbo; Li, Guoyan; Yang, Yuantao; Liang, Xihui; Xu, Minqiang

2018-05-01

The fault diagnosis of planetary gearboxes is crucial to reduce the maintenance costs and economic losses. This paper proposes a novel fault diagnosis method based on adaptive multi-scale morphological filter (AMMF) and modified hierarchical permutation entropy (MHPE) to identify the different health conditions of planetary gearboxes. In this method, AMMF is firstly adopted to remove the fault-unrelated components and enhance the fault characteristics. Second, MHPE is utilized to extract the fault features from the denoised vibration signals. Third, Laplacian score (LS) approach is employed to refine the fault features. In the end, the obtained features are fed into the binary tree support vector machine (BT-SVM) to accomplish the fault pattern identification. The proposed method is numerically and experimentally demonstrated to be able to recognize the different fault categories of planetary gearboxes.

Rapid fabrication of hierarchically structured supramolecular nanocomposite thin films in one minute

Energy Technology Data Exchange (ETDEWEB)

Xu, Ting; Kao, Joseph

2016-11-08

Functional nanocomposites containing nanoparticles of different chemical compositions may exhibit new properties to meet demands for advanced technology. It is imperative to simultaneously achieve hierarchical structural control and to develop rapid, scalable fabrication to minimize degradation of nanoparticle properties and for compatibility with nanomanufacturing. The assembly kinetics of supramolecular nanocomposite in thin films is governed by the energetic cost arising from defects, the chain mobility, and the activation energy for inter-domain diffusion. By optimizing only one parameter, the solvent fraction in the film, the assembly kinetics can be precisely tailored to produce hierarchically structured thin films of supramolecular nanocomposites in approximately one minute. Moreover, the strong wavelength dependent optical anisotropy in the nanocomposite highlights their potential applications for light manipulation and information transmission. The present invention opens a new avenue in designing manufacture-friendly continuous processing for the fabrication of functional nanocomposite thin films.

Hierarchical Targeting Strategy for Enhanced Tumor Tissue Accumulation/Retention and Cellular Internalization.

Science.gov (United States)

Wang, Sheng; Huang, Peng; Chen, Xiaoyuan

2016-09-01

Targeted delivery of therapeutic agents is an important way to improve the therapeutic index and reduce side effects. To design nanoparticles for targeted delivery, both enhanced tumor tissue accumulation/retention and enhanced cellular internalization should be considered simultaneously. So far, there have been very few nanoparticles with immutable structures that can achieve this goal efficiently. Hierarchical targeting, a novel targeting strategy based on stimuli responsiveness, shows good potential to enhance both tumor tissue accumulation/retention and cellular internalization. Here, the recent design and development of hierarchical targeting nanoplatforms, based on changeable particle sizes, switchable surface charges and activatable surface ligands, will be introduced. In general, the targeting moieties in these nanoplatforms are not activated during blood circulation for efficient tumor tissue accumulation, but re-activated by certain internal or external stimuli in the tumor microenvironment for enhanced cellular internalization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Physical properties of the GaPd2 intermetallic catalyst in bulk and nanoparticle morphology

DEFF Research Database (Denmark)

Wencka, M.; Schwerin, J.; Klanjšek, M.

2015-01-01

Intermetallic compound GaPd2 is a highly selective catalyst material for the semi-hydrogenation of acetylene. We have determined anisotropic electronic, thermal and magnetic properties of a GaPd2 monocrystal along three orthogonal orthorhombic directions of the structure. By using 69Ga and 71Ga NMR...... properties of the GaPd2 phase on going from the bulk material to the nanoparticles morphology, we have synthesized GaPd2/SiO2 supported nanoparticles and determined their electronic DOS at εF from the 71Ga NMR spin-lattice relaxation rate. The electronic DOS of the GaPd2 was also studied theoretically from...... spectroscopy, we have determined the electric-field-gradient tensor at the Ga site in the unit cell and the Knight shift, which yields the electronic density of states (DOS) at the Fermi energy εF. The DOS at εF was determined independently also from the specific heat. To see the change of electronic...

Nitrogen-doped hierarchical lamellar porous carbon synthesized from the fish scale as support material for platinum nanoparticle electrocatalyst toward the oxygen reduction reaction.

Science.gov (United States)

Liu, Haijing; Cao, Yinliang; Wang, Feng; Huang, Yaqin

2014-01-22

Novel hierarchical lamellar porous carbon (HLPC) with high BET specific surface area of 2730 m(2) g(-1) and doped by nitrogen atoms has been synthesized from the fish scale without any post-synthesis treatment, and applied to support the platinum (Pt) nanoparticle (NP) catalysts (Pt/HLPC). The Pt NPs could be highly dispersed on the porous surface of HLPC with a narrow size distribution centered at ca. 2.0 nm. The results of the electrochemical analysis reveal that the electrochemical active surface area (ECSA) of Pt/HLPC is larger than the Pt NP electrocatalyst supported on the carbon black (Pt/Vulcan XC-72). Compared with the Pt/Vulcan XC-72, the Pt/HLPC exhibits larger current density, lower overpotential, and enhanced catalytic activity toward the oxygen reduction reaction (ORR) through the direct four-electron pathway. The improved catalytic activity is mainly attributed to the high BET specific surface area, hierarchical porous structures and the nitrogen-doped surface property of HLPC, indicating the superiority of HLPC as a promising support material for the ORR electrocatalysts.

A Review on the Green Synthesis of Silver Nanoparticles and Their Morphologies Studied via TEM

Directory of Open Access Journals (Sweden)

Protima Rauwel

2015-01-01

Full Text Available Silver has been recognized as a nontoxic, safe inorganic antibacterial/antifungal agent used for centuries. Silver demonstrates a very high potential in a wide range of biological applications, more particularly in the form of nanoparticles. Environmentally friendly synthesis methods are becoming more and more popular in chemistry and chemical technologies and the need for ecological methods of synthesis is increasing; the aim is to reduce polluting reaction by-products. Another important advantage of green synthesis methods lies in its cost-effectiveness and in the abundance of raw materials. During the last five years, many efforts were put into developing new greener and cheaper methods for the synthesis of nanoparticles. The cost decrease and less harmful synthesis methods have been the motivation in comparison to other synthesis techniques where harmful reductive organic species produce hazardous by-products. This environment-friendly aspect has now become a major social issue and is instrumental in combatting environmental pollution through reduction or elimination of hazardous materials. This review describes a brief overview of the research on green synthesis of silver metal nanoparticles and the influence of the method on their size and morphology.

Intelligent hydrophilic nanoparticles fabricated via alkaline hydrolysis of crosslinked polyacrylonitrile nanoparticles

International Nuclear Information System (INIS)

Zhang, Y.; Wu, Q.; Zhang, H.; Zhao, J.

2013-01-01

Crosslinked polyacrylonitrile (PAN) nanolatex, with an average hydrodynamic diameter of 84 nm and a polydispersity index of 0.06, was successfully synthesized at a high monomer concentration and low surfactant content via a modified emulsion polymerization. Three measurements were adopted to control the nucleation and growth processes. Taking advantage of the chemical activity of nitrile groups, intelligent hydrophilic polymeric nanoparticles were fabricated via simple alkaline hydrolysis treatment of the crosslinked PAN nanolatex. Dynamic light scattering, electrophoretic light scattering, FT-IR spectroscopy, elemental analysis, and TEM observations were used to monitor the changes in the composition, structure, and morphology of the nanoparticles during the hydrolysis process. The sizes, chemical composition, morphology, and pH-responsive behavior of the intelligent hydrophilic nanoparticles could be adjusted by simply changing the hydrolysis time. As the hydrolysis was prolonged, the following nanoparticles could be obtained, crosslinked PAN nanoparticles with hydrophilic surfaces, amphiphilic nanoparticles with a hydrophobic PAN core and a hydrophilic polymeric shell composed of acrylamide and acrylic acid units, or carboxylic polyacrylamide nanoparticles. These modified nanoparticles all display good hydrophilicity, good biocompatibility, pH-sensitivity, as well as carboxyl functional groups, and thus are ideal candidates for various biomedical applications

Intelligent hydrophilic nanoparticles fabricated via alkaline hydrolysis of crosslinked polyacrylonitrile nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Zhang, Y., E-mail: zhyw@dhu.edu.cn; Wu, Q.; Zhang, H.; Zhao, J. [Donghua University, State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Chemical Fibers Research Institute (China)

2013-07-15

Crosslinked polyacrylonitrile (PAN) nanolatex, with an average hydrodynamic diameter of 84 nm and a polydispersity index of 0.06, was successfully synthesized at a high monomer concentration and low surfactant content via a modified emulsion polymerization. Three measurements were adopted to control the nucleation and growth processes. Taking advantage of the chemical activity of nitrile groups, intelligent hydrophilic polymeric nanoparticles were fabricated via simple alkaline hydrolysis treatment of the crosslinked PAN nanolatex. Dynamic light scattering, electrophoretic light scattering, FT-IR spectroscopy, elemental analysis, and TEM observations were used to monitor the changes in the composition, structure, and morphology of the nanoparticles during the hydrolysis process. The sizes, chemical composition, morphology, and pH-responsive behavior of the intelligent hydrophilic nanoparticles could be adjusted by simply changing the hydrolysis time. As the hydrolysis was prolonged, the following nanoparticles could be obtained, crosslinked PAN nanoparticles with hydrophilic surfaces, amphiphilic nanoparticles with a hydrophobic PAN core and a hydrophilic polymeric shell composed of acrylamide and acrylic acid units, or carboxylic polyacrylamide nanoparticles. These modified nanoparticles all display good hydrophilicity, good biocompatibility, pH-sensitivity, as well as carboxyl functional groups, and thus are ideal candidates for various biomedical applications.

Preparation of disk-like particles with micro/nano hierarchical structures.

Science.gov (United States)

Meng, Zhen; Yang, Wenbo; Chen, Pengpeng; Wang, Weina; Jia, Xudong; Xi, Kai

2013-10-15

A facile, reproductive method has been successfully developed to produce disk-like microparticles self-assembled from monodispersed hybrid silica nanoparticles under certain circumstance. The disk-like microparticles with micro/nano hierarchical structures could be obtained in large amount under a mild condition and further used to biomimetic design of the superhydrophobic surface of lotus leaf. After traditional surface modification with dodecyltrichlorosiliane, the static contact angle of water on the surface with micro/nano hierarchical structure could reach 168.8°. The method of surface modification could be further simplified by click reaction with the introduction of thiol groups under mild condition. The present strategy for constructing the surface with micro/nano hierarchical structures offers the advantage of simple and large area fabrication, which enables a variety of superhydrophobic applications. Copyright © 2013 Elsevier Inc. All rights reserved.

Synthesis of ferrofluids based on cobalt ferrite nanoparticles: Influence of reaction time on structural, morphological and magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Amirabadizadeh, Ahmad; Salighe, Zohre; Sarhaddi, Reza, E-mail: reza.sarhaddi@birjand.ac.ir; Lotfollahi, Zahra

2017-07-15

Highlights: • Ferrofluids based on cobalt ferrite nanoparticles were synthesized by co-precipitation method. • The crystallite and particle size of cobalt ferrite can be controlled effectively by reaction time. • The ferrofluids have lower values of saturation magnetization and coercivity as compared to nanoparticles. • By increasing the size of nanoparticles, the narrower and sharper spikes of ferrofluids are formed. - Abstract: In this work, for first time the ferrofluids based on the cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles were prepared by the co-precipitation method at different reaction times (0.5–6.5 h). Crystal structure, morphology and magnetic properties of the cobalt ferrite nanoparticles and the ferrofluids based on the nanoparticles were studied by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and vibrating sample magnetometer (VSM). The XRD patterns of CoFe{sub 2}O{sub 4} nanoparticles synthesized at different reaction times indicated that all samples are single phase in accordance with inverse cubic spinel structure with space group Fd-3m, and no impurity phase was observed. By increasing the reaction time to 3.5 h, the lattice parameter and the average crystallites size increased and then afterwards decreased by increasing the reaction time. The microscopic studies indicated the formation of nanosized particles with nearly spherical in shape, whereas the average particle size for all samples is found to be less than 50 nm. The results of VSM also showed that the saturation magnetization and coercivity field of the cobalt ferrite nanoparticles and the ferrofluids were influenced by reaction time, whereas the ferrofluids have lower values of magnetic parameters than that of nanoparticles.

The MIL-88A-Derived Fe3O4-Carbon Hierarchical Nanocomposites for Electrochemical Sensing

Science.gov (United States)

Wang, Li; Zhang, Yayun; Li, Xia; Xie, Yingzhen; He, Juan; Yu, Jie; Song, Yonghai

2015-01-01

Metal or metal oxides/carbon nanocomposites with hierarchical superstructures have become one of the most promising functional materials in sensor, catalysis, energy conversion, etc. In this work, novel hierarchical Fe3O4/carbon superstructures have been fabricated based on metal-organic frameworks (MOFs)-derived method. Three kinds of Fe-MOFs (MIL-88A) with different morphologies were prepared beforehand as templates, and then pyrolyzed to fabricate the corresponding novel hierarchical Fe3O4/carbon superstructures. The systematic studies on the thermal decomposition process of the three kinds of MIL-88A and the effect of template morphology on the products were carried out in detail. Scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy and thermal analysis were employed to investigate the hierarchical Fe3O4/carbon superstructures. Based on these resulted hierarchical Fe3O4/carbon superstructures, a novel and sensitive nonenzymatic N-acetyl cysteine sensor was developed. The porous and hierarchical superstructures and large surface area of the as-formed Fe3O4/carbon superstructures eventually contributed to the good electrocatalytic activity of the prepared sensor towards the oxidation of N-acetyl cysteine. The proposed preparation method of the hierarchical Fe3O4/carbon superstructures is simple, efficient, cheap and easy to mass production. It might open up a new way for hierarchical superstructures preparation. PMID:26387535

Morphological and Rheological Characterization of Gold Nanoparticles Synthesized Using Pluronic P103 as Soft Template

OpenAIRE

Nancy Tepale; Victor V. A. Fernández-Escamilla; Carlos Álvarez; Eric Flores-Aquino; Valeria J. González-Coronel; Daniel Cruz; Manuel Sánchez-Cantú

2016-01-01

The synthesis of gold nanoparticles (Au-NPs), using Pluronic® P103 as soft template to design tuned hybrid gold/P103 nanomaterials, is reported here. The effect of the concentration of P103 and the synthesis temperature on the growth, size, and morphology of Au-NPs were studied. The rheological properties of these hybrid nanomaterials at different measured temperatures were studied as well. By increasing the concentration of P103, the micelles progressively grew due to an increase in the numb...

Effect of solvent medium on the structural, morphological and optical properties of ZnS nanoparticles synthesized by solvothermal route

Energy Technology Data Exchange (ETDEWEB)

Mendil, R., E-mail: radia.mendil@yahoo.fr [Laboratoire de Physique des Matériaux et des Nanomatériaux appliquée à l' Environnement, Université de Gabès, Faculté des Sciences de Gabès, Cité Erriadh Manara Zrig, 6072 Gabès (Tunisia); Ben Ayadi, Z. [Laboratoire de Physique des Matériaux et des Nanomatériaux appliquée à l' Environnement, Université de Gabès, Faculté des Sciences de Gabès, Cité Erriadh Manara Zrig, 6072 Gabès (Tunisia); Djessas, K. [Laboratoire Procédés, Matériaux et Energie Solaire (PROMES-CNRS), TECNOSUD, Rambla de la thermodynamique, 66100 Perpignan (France); Université de Perpignan Via Domitia, 52 avenue Paul Alduy, 68860, Perpignan Cedex9 (France)

2016-09-05

Different morphologies of ZnS have been synthesized by a facile solvothermal approach in a mixed solvent made of Ethylenediamine (EN) and distilled water. The effect of solvent medium on the structural, morphological and optical properties of ZnS nanoparticles were investigated. The formation mechanism of different morphologies was proposed based on the experiment results. The as-prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), Raman spectroscopy and UV-Vis-IR spectrophotometer. The results show that phase transformation is easily induced and there is a strong correlation between morphology and structure of the ZnS nanocrystals by changing the solvent. The results also show that we have successfully produced hexagonal phase ZnS nanorods with mixed solvent. The grain sizes in the range of 17–22 nm were obtained according to elaboration conditions. Raman spectra show the intense peak at 346 cm{sup −1}, which is a typical Raman peak of bulk ZnS crystal, no signature of secondary phases. The band gap of ZnS increased from 3.49 to 3.74 eV with an increase in the EN composition in the solvent, implying that the optical properties of these materials are clearly affected by the synthesis medium. - Highlights: • ZnS was prepared at low temperature using solvothermal method. • The phase transformation and shape evolution processes were studied. • The role of solvent (EN/W) has been discussed for formation of ZnS nanostructures with different morphology. • The properties and growth mechanism of ZnS nanoparticles were investigated. • Optical band gap of ZnS powder were investigated using UV vis spectroscopy.

The assessment of pore connectivity in hierarchical zeolites using positron annihilation lifetime spectroscopy: instrumental and morphological aspects.

Science.gov (United States)

Zubiaga, Asier; Warringham, Robbie; Boltz, Marilyne; Cooke, David; Crivelli, Paolo; Gidley, David; Pérez-Ramírez, Javier; Mitchell, Sharon

2016-04-07

Recent studies demonstrated the power of positron annihilation lifetime spectroscopy (PALS) to characterise the connectivity and corresponding effectiveness of hierarchical pore networks in zeolites. This was based on the fractional escape of ortho-positronium (Ps), formed within the micropore framework, to vacuum. To further develop this technique, here we assess the impact of the positron implantation energy and of the zeolite crystal size and the particle morphology. Conventional measurements using fast positrons and beam measurements applying moderated positrons both readily distinguish purely microporous ZSM-5 zeolites comprised of single crystals or crystal aggregates. Unlike beam measurements, however, conventional measurements fail to discriminate model hierarchical zeolites with open or constricted mesopore architectures. Several steps are taken to rationalise these observations. The dominant contribution of Ps diffusion to the PALS response is confirmed by capping the external surface of the zeolite crystals with tetraethylorthosilicate, which greatly enhances the sensitivity to the micropore network. A one-dimensional model is constructed to predict the out-diffusion of Ps from a zeolite crystal, which is validated experimentally by comparing coffin-shaped single crystals of varying size. Calculation of the trends expected on the application of fast or moderated positrons indicates that the distinctions in the initial distribution of Ps at the crystal level cannot explain the limited sensitivity of the former to the mesopore architecture. Instead, we propose that the greater penetration of fast positrons within the sample increases the probability of Ps re-entry from intercrystalline voids into mesopores connected with the external surface of zeolite crystals, thereby reducing their fractional escape.

Effects of precursor on the morphology and size of ZrO2 nanoparticles, synthesized by sol-gel method in non-aqueous medium

Directory of Open Access Journals (Sweden)

Mohammed Rafiq Hussain Siddiqui

2012-12-01

Full Text Available Pure zirconium oxide (ZrO2 nanoparticles with diameters 10-25 nm were synthesized from ZrOCl2.8H2O and Zr(SO42.H2O with benzyl alcohol as non-aqueous solvent medium using sol-gel method. Sodium lauryl sulfate was added as surfactants to control the particle size. The synthesized ZrO2 nanoparticles have a mixture of tetragonal and monoclinic structure. The XRD showed the purity of obtained ZrO2 nanoparticles with tetragonal and monoclinic phase and the crystallite size for ZrOCl2.8H2O precursor was estimated to be 18.1 nm and that from Zr(SO42.H2O was 9.7 nm. The transmission electron microscopy and scanning electron microscopic studies also shows different sizes of nanoparticles and different morphology depending on the precursor used for the synthesis of ZrO2 nanoparticles

Effects of precursor on the morphology and size of ZrO2 nanoparticles, synthesized by sol-gel method in non-aqueous medium

International Nuclear Information System (INIS)

Siddiqui, Mohammed Rafiq Hussain; Al-Wassil, Abdulaziz Ibrahim; Mahfouz, Refaat Mohamad; Al-Otaibi, Abdullah Mohmmed

2012-01-01

Pure zirconium oxide (ZrO 2 ) nanoparticles with diameters 10-25 nm were synthesized from ZrOCl 2 .8H 2 O and Zr(SO 4 )2.H 2 O with benzyl alcohol as non-aqueous solvent medium using sol-gel method. Sodium lauryl sulfate was added as surfactants to control the particle size. The synthesized ZrO 2 nanoparticles have a mixture of tetragonal and monoclinic structure. The XRD showed the purity of obtained ZrO 2 nanoparticles with tetragonal and monoclinic phase and the crystallite size for ZrOCl 2 .8H 2 O precursor was estimated to be 18.1 nm and that from Zr(SO 4 )2.H 2 O was 9.7 nm. The transmission electron microscopy and scanning electron microscopic studies also shows different sizes of nanoparticles and different morphology depending on the precursor used for the synthesis of ZrO 2 nanoparticles. (author)

Facile synthesis of both needle-like and spherical hydroxyapatite nanoparticles: Effect of synthetic temperature and calcination on morphology, crystallite size and crystallinity

International Nuclear Information System (INIS)

Wijesinghe, W.P.S.L.; Mantilaka, M.M.M.G.P.G.; Premalal, E.V.A.; Herath, H.M.T.U.; Mahalingam, S.; Edirisinghe, M.; Rajapakse, R.P.V.J.; Rajapakse, R.M.G.

2014-01-01

Synthetic hydroxyapatite (HA) nanoparticles, that mimic natural HA, are widely used as biocompatible coatings on prostheses to repair and substitute human bones. In this study, HA nanoparticles are prepared by precipitating them from a precursor solution containing calcium sucrate and ammonium dihydrogen orthophosphate, at a Ca/P mole ratio of 1.67:1, at temperatures, ranging from 10 °C to 95 °C. A set of products, prepared at different temperatures, is analyzed for their crystallinity, crystallite size, morphology, thermal stability and composition, by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopic techniques, while the other set is analyzed after calcining the respective products, soon after their synthesis, for 3 h, at 700 °C. The as-prepared products, after 2 h of drying, without any calcination, are not crystalline, but they grow very slowly into needle-like morphologies, as they are ripened with time. The percentage crystallinity of the final products increases from 15% to 52%, with increasing the preparative temperature. The calcined samples always produce spherical nanoparticles of essentially the same diameter, between 90 nm and 100 nm, which does not change due to aging and preparative temperatures. Therefore, the same method can be utilized to synthesize both spherical and needle-like nanoparticles of hydroxyapatite, with well-defined sizes and shapes. The ability to use readily available cheap raw materials, for the synthesis of such well-defined crystallites of hydroxyapatite, is an added advantage of this method, which may be explored further for the scaling up of the procedures to suit to industrial scale synthesis of such hydroxyapatite nanoparticles. - Highlights: • Hydroxyapatite nanoparticles are synthesized using a simple precipitation method. • Both needle-like and spherical hydroxyapatite nanoparticles are synthesized. • The prepared

Facile synthesis of both needle-like and spherical hydroxyapatite nanoparticles: Effect of synthetic temperature and calcination on morphology, crystallite size and crystallinity

Energy Technology Data Exchange (ETDEWEB)

Wijesinghe, W.P.S.L.; Mantilaka, M.M.M.G.P.G. [Department of Chemistry, Faculty of Science, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Post-graduate Institute of Science, P.O. Box: 25, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Premalal, E.V.A. [Department of Materials Science, Shizuoka University, Johoku, Naka-ku Hamamatsu, 432-8011 (Japan); Herath, H.M.T.U. [Department of Medical Laboratory Science, Faculty of Allied Health Sciences, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Mahalingam, S.; Edirisinghe, M. [Department of Mechanical Engineering, University College London, London WC1E 7JE (United Kingdom); Rajapakse, R.P.V.J. [Department of Veterinary Pathobiology, Faculty of Veterinary, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Rajapakse, R.M.G., E-mail: rmgr@pdn.ac.lk [Department of Chemistry, Faculty of Science, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Post-graduate Institute of Science, P.O. Box: 25, University of Peradeniya, Peradeniya 20400 (Sri Lanka)

2014-09-01

Synthetic hydroxyapatite (HA) nanoparticles, that mimic natural HA, are widely used as biocompatible coatings on prostheses to repair and substitute human bones. In this study, HA nanoparticles are prepared by precipitating them from a precursor solution containing calcium sucrate and ammonium dihydrogen orthophosphate, at a Ca/P mole ratio of 1.67:1, at temperatures, ranging from 10 °C to 95 °C. A set of products, prepared at different temperatures, is analyzed for their crystallinity, crystallite size, morphology, thermal stability and composition, by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopic techniques, while the other set is analyzed after calcining the respective products, soon after their synthesis, for 3 h, at 700 °C. The as-prepared products, after 2 h of drying, without any calcination, are not crystalline, but they grow very slowly into needle-like morphologies, as they are ripened with time. The percentage crystallinity of the final products increases from 15% to 52%, with increasing the preparative temperature. The calcined samples always produce spherical nanoparticles of essentially the same diameter, between 90 nm and 100 nm, which does not change due to aging and preparative temperatures. Therefore, the same method can be utilized to synthesize both spherical and needle-like nanoparticles of hydroxyapatite, with well-defined sizes and shapes. The ability to use readily available cheap raw materials, for the synthesis of such well-defined crystallites of hydroxyapatite, is an added advantage of this method, which may be explored further for the scaling up of the procedures to suit to industrial scale synthesis of such hydroxyapatite nanoparticles. - Highlights: • Hydroxyapatite nanoparticles are synthesized using a simple precipitation method. • Both needle-like and spherical hydroxyapatite nanoparticles are synthesized. • The prepared

Synthesis of hierarchical worm-like SnO2@C aggregates and their enhanced lithium storage properties

International Nuclear Information System (INIS)

Wu, Zhen-Guo; Li, Jun-Tao; Zhong, Yan-Jun; Liu, Jie; Guo, Xiao-Dong; Huang, Ling; Zhong, Ben-He; Sun, Shi-Gang

2015-01-01

Highlights: • The hierarchical worm-like SnO 2 @C aggregates were synthesized. • The hierarchical worm-like SnO 2 @C unit is assembled by nanowires. • The cycling performances of SnO 2 @C aggregates are improved. • A capacity of 477.0 mA h g −1 at 400 mA g −1 could be obtained after 60 cycles. - Abstract: The present paper reports a synthetic strategy of hierarchical worm-like SnO 2 @C aggregates with enhanced electrochemical performances. Specifically, a glucose-assisted hydrothermal treatment of the intermediate Co–Sn alloy nanoparticles, which were formed by carbothermal reduction of mixed commercial SnO 2 and Co 3 O 4 nanoparticles. The SnO 2 @C sample exhibits enhanced cycling performance in comparison with raw commercial SnO 2 nanoparticles and intermediate Co–Sn alloy nanoparticles when used as anode of lithium ion battery. A stable capacity of 533.6 mA h g −1 at 100 mA g −1 and 477.0 mA h g −1 at 400 mA g −1 remains after 60 cycles. When the current density increases to 1600 mA g −1 , the SnO 2 @C sample still deliver a high capacity of 384.2 mA h g −1 . The superior electrochemical performances could be attributed to the synergistic effect of unique worm-like aggregates structure and carbon surface-layer, which facilitate the electron transportation and buffer the large volume change

Structural, optical, morphological and dielectric properties of cerium oxide nanoparticles

International Nuclear Information System (INIS)

Prabaharan, Devadoss Mangalam Durai Manoharadoss; Sadaiyandi, Karuppasamy; Mahendran, Manickam; Sagadevan, Suresh

2016-01-01

Cerium oxide (CeO 2 ) nanoparticles were prepared by the precipitation method. The average crystallite size of cerium oxide nanoparticles was calculated from the X-ray diffraction (XRD) pattern and found to be 11 nm. The FT-IR spectrum clearly indicated the strong presence of cerium oxide nanoparticles. Raman spectrum confirmed the cubic nature of the cerium oxide nanoparticles. The Scanning Electron Microscopy (SEM) analysis showed that the nanoparticles agglomerated forming spherical-shaped particles. The Transmission Electron Microscopic (TEM) analysis confirmed the prepared cerium oxide nanoparticles with the particle size being found to be 16 nm. The optical absorption spectrum showed a blue shift by the cerium oxide nanoparticles due to the quantum confinement effect. The dielectric properties of cerium oxide nanoparticles were studied for different frequencies at different temperatures. The dielectric constant and the dielectric loss of the cerium oxide nanoparticles decreased with increase in frequency. The AC electrical conductivity study revealed that the conduction depended on both the frequency and the temperature. (author)

Structural, optical, morphological and dielectric properties of cerium oxide nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Prabaharan, Devadoss Mangalam Durai Manoharadoss [Department of Physics, NPR College of Engineering and Technology, Natham, Dindigul, Tamil Nadu (India); Sadaiyandi, Karuppasamy [Department of Physics, Alagappa Government Arts College, Karaikudi, Sivaganga, Tamil Nadu (India); Mahendran, Manickam [Department of Physics, Thiagarajar College of Engineering, Madurai, Tamil Nadu (India); Sagadevan, Suresh, E-mail: duraiphysics2011@gmail.com [Department of Physics, AMET University (India)

2016-03-15

Cerium oxide (CeO{sub 2}) nanoparticles were prepared by the precipitation method. The average crystallite size of cerium oxide nanoparticles was calculated from the X-ray diffraction (XRD) pattern and found to be 11 nm. The FT-IR spectrum clearly indicated the strong presence of cerium oxide nanoparticles. Raman spectrum confirmed the cubic nature of the cerium oxide nanoparticles. The Scanning Electron Microscopy (SEM) analysis showed that the nanoparticles agglomerated forming spherical-shaped particles. The Transmission Electron Microscopic (TEM) analysis confirmed the prepared cerium oxide nanoparticles with the particle size being found to be 16 nm. The optical absorption spectrum showed a blue shift by the cerium oxide nanoparticles due to the quantum confinement effect. The dielectric properties of cerium oxide nanoparticles were studied for different frequencies at different temperatures. The dielectric constant and the dielectric loss of the cerium oxide nanoparticles decreased with increase in frequency. The AC electrical conductivity study revealed that the conduction depended on both the frequency and the temperature. (author)

Hierarchical top-porous/bottom-tubular TiO 2 nanostructures decorated with Pd nanoparticles for efficient photoelectrocatalytic decomposition of synergistic pollutants

KAUST Repository

Zhang, Zhonghai

2012-02-22

In this paper, top-porous and bottom-tubular TiO 2 nanotubes (TiO 2 NTs) loaded with palladium nanoparticles (Pd/TiO 2 NTs) were fabricated as an electrode for an enhanced photoelectrocatalytic (PEC) activity toward organic dye decomposition. TiO 2 NTs with a unique hierarchical top-porous and bottom-tubular structure were prepared by a facile two-step anodization method and Pd nanoparticles were decorated onto the TiO 2 NTs via a photoreduction process. The PEC activity of Pd/TiO 2 NTs was investigated by decomposition of methylene blue (MB) and Rhodamine B (RhB). Because of formation Schottky junctions between TiO 2 and Pd, which significantly promoted the electron transfer and reduced the recombination of photogenerated electrons and holes, the Pd/TiO 2 NT electrode showed significantly higher PEC activities than TiO 2 NTs. Interestingly, an obvious synergy between two dyes was observed and corresponding mechanism based on facilitated transfer of electrons and holes as a result of a suitable energy level alignment was suggested. The findings of this work provide a fundamental insight not only into the fabrication but also utility of Schottky junctions for enhanced environmental remediation processes. © 2012 American Chemical Society.

Visible-light photocatalytic activity of Ag2O coated Bi2WO6 hierarchical microspheres assembled by nanosheets

International Nuclear Information System (INIS)

Chen, Lin; Hua, Hao; Yang, Qi; Hu, Chenguo

2015-01-01

Graphical abstract: - Highlights: • Bi 2 WO 6 hierarchical microspheres assembled by nanosheets and dispersed nanosheets are synthesized. • Ag 2 O/Bi 2 WO 6 heterostuctures exhibites an enhanced photocatalytic activity compared with the Bi 2 WO 6 nanostructures. • Photocatalytic activity of the Ag 2 O/Bi 2 WO 6 microspheres is higher than that of the nanosheets. • Bi 2 WO 6 hierarchical structure is an excellent architecture for loading of Ag 2 O nanoparticles. - Abstract: Bi 2 WO 6 hierarchical microspheres assembled by nanosheets and dispersed nanosheets were synthesized by hydrothermal reaction in different conditions. Ag 2 O nanoparticles were deposited on the surface of Bi 2 WO 6 microspheres and nanosheets by the chemical precipitation method. The photocatalytic performance of pure Bi 2 WO 6 nanostructures and Ag 2 O/Bi 2 WO 6 heterostructures were evaluated by the photocatalytic decolorization of RhB solution under visible-light irradiation. Compared with the pure Bi 2 WO 6 nanostructures, the Ag 2 O/Bi 2 WO 6 heterostructures exhibited an obviously enhanced photocatalytic activity. And photocatalytic activity of the Ag 2 O/Bi 2 WO 6 microspheres is higher than that of the Ag 2 O/Bi 2 WO 6 nanosheets. This work demonstrates that the Bi 2 WO 6 hierarchical three-dimensional structure is an excellent architecture for the loading of Ag 2 O nanoparticles to build a highly efficient photocatalyst

Morphology control of polymer: Fullerene solar cells by nanoparticle self-assembly

Science.gov (United States)

Zhang, Wenluan

During the past two decades, research in the field of polymer based solar cells has attracted great effort due to their simple processing, mechanical flexibility and potential low cost. A standard polymer solar cell is based on the concept of a bulk-heterojunction composed of a conducting polymer as the electron donor and a fullerene derivative as the electron acceptor. Since the exciton lifetime is limited, this places extra emphasis on control of the morphology to obtain improved device performance. In this thesis, detailed characterization and novel morphological design of polymer solar cells was studied, in addition, preliminary efforts to transfer laboratory scale methods to industrialized device fabrication was made. Magnetic contrast neutron reflectivity was used to study the vertical concentration distribution of fullerene nanoparticles within poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2- b]thiophene (pBTTT) thin film. Due to the wide space between the side chains of polymer, these fullerene nanoparticles intercalate between them creating a stable co-crystal structure. Therefore, a high volume fraction of fullerene was needed to obtain optimal device performance as phase separated conductive pathways are required and resulted in a homogeneous fullerene concentration profile through the film. Small angle neutron scattering was used to find there is amorphous fullerene even at lower concentration since it was previously believed that all fullerene formed a co-crystal. These fullerene molecules evolve into approximately 15 nm sized agglomerates at higher concentrations to improve electron transport. Unfortunately, thermal annealing gives these agglomerates mobility to form micrometer sized crystals and reduce the device performance. In standard poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PCMBM) solar cells, a higher concentration of PCBM at the cathode interface is desired due to the band alignment structure. This was

Hierarchical Structure in Semicrystalline Polymers Tethered to Nanospheres

KAUST Repository

Kim, Sung A

2014-01-28

We report on structural and dynamic transitions of polymers tethered to nanoparticles. In particular, we use X-ray diffraction, vibrational spectroscopy, and thermal measurements to investigate multiscale structure and dynamic transitions of poly(ethylene glycol) (PEG) chains densely grafted to SiO2 nanoparticles. The approach used for synthesizing these hybrid particles leads to homogeneous SiO2-PEG composites with polymer grafting densities as high as 1.5 chains/nm2, which allows the hybrid materials to exist as self-suspended suspensions with distinct hierarchical structure and thermal properties. On angstrom and nanometer length scales, the tethered PEG chains exhibit more dominant TTG conformations and helix unit cell structure, in comparison to the untethered polymer. The nanoparticle tethered PEG chains are also reported to form extended crystallites on tens of nanometers length scales and to exhibit more stable crystalline structure on small dimensions. On length scales comparable to the size of each hybrid SiO 2-PEG unit, the materials are amorphous presumably as a result of the difficulty fitting the nanoparticle anchors into the PEG crystal lattice. This structural change produces large effects on the thermal transitions of PEG molecules tethered to nanoparticles. © 2014 American Chemical Society.

Study of the Effect of Nanoparticles and Surface Morphology on Reverse Osmosis and Nanofiltration Membrane Productivity

Directory of Open Access Journals (Sweden)

Steven J. Duranceau

2013-08-01

Full Text Available To evaluate the significance of reverse osmosis (RO and nanofiltration (NF surface morphology on membrane performance, productivity experiments were conducted using flat-sheet membranes and three different nanoparticles, which included SiO2, TiO2 and CeO2. In this study, the productivity rate was markedly influenced by membrane surface morphology. Atomic force microscopy (AFM analysis of membrane surfaces revealed that the higher productivity decline rates associated with polyamide RO membranes as compared to that of a cellulose acetate NF membrane was due to the inherent ridge-and-valley morphology of the active layer. The unique polyamide active layer morphology was directly related to the surface roughness, and was found to contribute to particle accumulation in the valleys causing a higher flux decline than in smoother membranes. Extended RO productivity experiments using laboratory grade water and diluted pretreated seawater were conducted to compare the effect that different nanoparticles had on membrane active layers. Membrane flux decline was not affected by particle type when the feed water was laboratory grade water. On the other hand, membrane productivity was affected by particle type when pretreated diluted seawater served as feed water. It was found that CeO2 addition resulted in the least observable flux decline, followed by SiO2 and TiO2. A productivity simulation was conducted by fitting the monitored flux data into a cake growth rate model, where the model was modified using a finite difference method to incorporate surface thickness variation into the analysis. The ratio of cake growth term (k1 and particle back diffusion term (k2 was compared in between different RO and NF membranes. Results indicated that k2 was less significant for surfaces that exhibited a higher roughness. It was concluded that the valley areas of thin-film membrane surfaces have the ability to capture particles, limiting particle back diffusion.

Control of morphology and surface wettability of anodic niobium oxide microcones formed in hot phosphate-glycerol electrolytes

International Nuclear Information System (INIS)

Yang, Shu; Habazaki, Hiroki; Fujii, Takashi; Aoki, Yoshitaka; Skeldon, Peter; Thompson, George E.

2011-01-01

Highlights: → Anodic niobium oxide microcones with nanofiber morphology are formed simply by anodizing. → The cone size and its tip angle are controlled by anodizing condition. → The surface shows extremely high contact angle for water after coating with a fluoroalkyl layer. - Abstract: We report the fabrication of superhydrophobic surfaces with a hierarchical morphology by self-organized anodizing process. Simply by anodizing of niobium metal in hot phosphate-glycerol electrolyte, niobium oxide microcones, consisting of highly branched oxide nanofibers, develop on the surface. The size of the microcones and their tip angles are controlled by changing the applied potential difference in anodizing and the water content in the electrolyte. Reduction of the water content increases the size of the microcones, with the nanofibers changing to nanoparticles. The size of microcones is also reduced by increasing the applied potential difference, without influencing the tip angle. The hierarchical oxide surfaces are superhydrophilic, with static contact angles close to 0 o . Coating of the anodic oxide films with a monolayer of fluoroalkyl phosphate makes the surfaces superhydrophobic with a contact angle for water as high as 175 o and a very small contact angle hysteresis of only 2 o . The present results indicate that the larger microcones with smaller tip angles show the higher contact angle for water.

Lecithin-based wet chemical precipitation of hydroxyapatite nanoparticles.

Science.gov (United States)

Michał, Wojasiński; Ewa, Duszyńska; Tomasz, Ciach

Hydroxyapatite Ca 10 (PO 4 ) 6 (OH) 2 nanoparticles have been successfully synthesized by the wet chemical precipitation method at 60 °C in the presence of biocompatible natural surfactant-lecithin. The composition and morphology of nanoparticles of hydroxyapatite synthesized with lecithin (nHAp-PC) was studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Size distribution for nanoparticles was measured by nanoparticle tracking analysis in NanoSight system. We discuss in details influence of lecithin concentration in reaction system on nHAp-PC morphology, as well as on size distributions and suspendability of nanoparticles. Product exhibits crystalline structure and chemical composition of hydroxyapatite, with visible traces of lecithin. Difference in surfactant amounts results in changes in particles morphology and their average size.

Development of hierarchically porous cobalt oxide for enhanced photo-oxidation of indoor pollutants

Energy Technology Data Exchange (ETDEWEB)

Cheng, J. P., E-mail: chengjp@zju.edu.cn [Zhejiang University, State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering (China); Shereef, Anas; Gray, Kimberly A., E-mail: k-gray@northwestern.edu [Northwestern University, Center for Catalysis and Surface Science (United States); Wu, Jinsong [Northwestern University, Department of Materials Science and Engineering (United States)

2015-03-15

Porous cobalt oxide was successfully prepared by precipitation of cobalt hydroxide followed by low temperature thermal decomposition. The morphologies of the resultant oxides remained as the corresponding hydroxides, although the morphology of cobalt hydroxides was greatly influenced by the precursor salts. The cobalt oxides with average crystal size less than 20 nm were characterized by X-ray diffraction, scanning electron microscope, BET surface area, and XPS analysis. The photocatalytic activities of the various cobalt oxides morphologies were investigated by comparing the photo-degradation of acetaldehyde under simulated solar illumination. Relative to their low order structures and reference titania samples, the hierarchical nanostructures of cobalt oxide showed excellent abilities to rapidly degrade acetaldehyde, a model air pollutant. This was attributed to the unique nature of these hierarchical cobalt oxide nanoassemblies, which contained many catalytically active reaction sites and open pores.

Advantages and Limitations of Current Imaging Techniques for Characterizing Liposome Morphology

Directory of Open Access Journals (Sweden)

Annie-Louise Robson

2018-02-01

Full Text Available There are currently a number of imaging techniques available for evaluating the morphology of liposomes and other nanoparticles, with each having its own advantages and disadvantages that should be considered when interpreting data. Controlling and validating the morphology of nanoparticles is of key importance for the effective clinical translation of liposomal formulations. There are a number of physical characteristics of liposomes that determine their in vivo behavior, including size, surface characteristics, lamellarity, and homogeneity. Despite the great importance of the morphology of nanoparticles, it is generally not well-characterized and is difficult to control. Appropriate imaging techniques provide important details regarding the morphological characteristics of nanoparticles, and should be used in conjunction with other methods to assess physicochemical parameters. In this review, we will discuss the advantages and limitations of available imaging techniques used to evaluate liposomal formulations.

Hierarchical VOOH hollow spheres for symmetrical and asymmetrical supercapacitor devices

Science.gov (United States)

Jing, Xuyang; Wang, Cong; Feng, Wenjing; Xing, Na; Jiang, Hanmei; Lu, Xiangyu; Zhang, Yifu; Meng, Changgong

2018-01-01

Hierarchical VOOH hollow spheres with low crystallinity composed of nanoparticles were prepared by a facile and template-free method, which involved a precipitation of precursor microspheres in aqueous solution at room temperature and subsequent hydrothermal reaction. Quasi-solid-state symmetric and asymmetric supercapacitor (SSC and ASC) devices were fabricated using hierarchical VOOH hollow spheres as the electrodes, and the electrochemical properties of the VOOH//VOOH SSC device and the VOOH//AC ASC device were studied by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). Results demonstrated that the electrochemical performance of the VOOH//AC ASC device was better than that of the VOOH//VOOH SSC device. After 3000 cycles, the specific capacitance of the VOOH//AC ASC device retains 83% of the initial capacitance, while the VOOH//VOOH SSC device retains only 7.7%. Findings in this work proved that hierarchical VOOH hollow spheres could be a promising candidate as an ideal electrode material for supercapacitor devices.

Fabrication of highly hydrophobic two-component thermosetting polyurethane surfaces with silica nanoparticles

Science.gov (United States)

Yang, Guang; Song, Jialu; Hou, Xianghui

2018-05-01

Highly hydrophobic thermosetting polyurethane (TSU) surfaces with micro-nano hierarchical structures were developed by a simple process combined with sandpaper templates and nano-silica embellishment. Sandpapers with grit sizes varying from 240 to 7000 grit were used to obtain micro-scale roughness on an intrinsic hydrophilic TSU surface. The surface wettability was investigated by contact angle measurement. It was found that the largest contact angle of the TSU surface without nanoparticles at 102 ± 3° was obtained when the template was 240-grit sandpaper and the molding progress started after 45 min curing of TSU. Silica nanoparticles modified with polydimethylsiloxane were scattered onto the surfaces of both the polymer and the template to construct the desirable nanostructures. The influences of the morphology, surface composition and the silica content on the TSU surface wettability were studied by scanning electron microscopy (SEM), attenuated total reflection (ATR) infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The surface of the TSU/SiO2 nanocomposites containing 4 wt% silica nanoparticles exhibited a distinctive dual-scale structure and excellent hydrophobicity with the contact angle above 150°. The mechanism of wettability was also discussed by Wenzel model and Cassie-Baxter model.

Moisture condensation behavior of hierarchically carbon nanotube-grafted carbon nanofibers.

Science.gov (United States)

Park, Kyu-Min; Lee, Byoung-Sun; Youk, Ji Ho; Lee, Jinyong; Yu, Woong-Reol

2013-11-13

Hierarchical micro/nanosurfaces with nanoscale roughness on microscale uneven substrates have been the subject of much recent research interest because of phenomena such as superhydrophobicity. However, an understanding of the effect of the difference in the scale of the hierarchical entities, i.e., nanoscale roughness on microscale uneven substrates as opposed to nanoscale roughness on (a larger) nanoscale uneven surface, is still lacking. In this study, we investigated the effect of the difference in scale between the nano- and microscale features. We fabricated carbon nanotube-grafted carbon nanofibers (CNFs) by dispersing a catalyst precursor in poly (acrylonitrile) (PAN) solution, electrospinning the PAN/catalyst precursor solution, carbonization of electrospun PAN nanofibers, and direct growth of carbon nanotubes (CNTs) on the CNFs. We investigated the relationships between the catalyst concentrations, the size of catalyst nanoparticles on CNFs, and the sizes of CNFs and CNTs. Interestingly, the hydrophobic behavior of micro/nano and nano/nano hierarchical surfaces with water droplets was similar; however a significant difference in the water condensation behavior was observed. Water condensed into smaller droplets on the nano/nano hierarchical surface, causing it to dry much faster.

Hierarchically structured graphene-carbon nanotube-cobalt hybrid electrocatalyst for seawater battery

Science.gov (United States)

Suh, Dong Hoon; Park, Sul Ki; Nakhanivej, Puritut; Kim, Youngsik; Hwang, Soo Min; Park, Ho Seok

2017-12-01

The design of cost-effective and highly active catalysts is a critical challenge. Inspired by the strong points of stability and conductivity of carbon nanotubes (CNTs), high catalytic activity of Co nanoparticles, and rapid ion diffusion and large accessible area of three-dimensional (3D) graphene, we demonstrate a novel strategy to construct a hierarchical hybrid structure consisting of Co/CoOx nanoparticles-incorporated CNT branches onto the 3D reduced graphene oxide (rGO) architecture. The surface-modified 3D rGO by steam activation process has a large surface area and abundant defect sites, which serve as active sites to uniformly grow Co/CoOx nanoparticles. Furthermore, the CNTs preserve their performance stably by encapsulating Co nanoparticles, while the uniformly decorated Co/CoOx nanoparticles exhibit superior electrocatalytic activity toward oxygen evolution/reduction reaction due to highly exposed active sites. Employing the hybrid particle electrocatalyst, the seawater battery operates stably at 0.01 mA cm-2 during 50 cycles, owing to the good electrocatalytic ability.

Ionothermal synthesis of hierarchical BiOBr microspheres for water treatment

Energy Technology Data Exchange (ETDEWEB)

Zhang, Dieqing [The Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, 100 Guilin Road, Shanghai 200231 (China); Department of Chemistry and Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong (China); Wen, Meicheng; Jiang, Bo; Li, Guisheng [The Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, 100 Guilin Road, Shanghai 200231 (China); Yu, Jimmy C., E-mail: jimyu@cuhk.edu.hk [Department of Chemistry and Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong (China)

2012-04-15

Graphical abstract: Hierarchical BiOBr microspheres were prepared from a bromine-containing ionic liquid. The material was found effective for removing heavy metals, degrading organic pollutants and killing bacteria. Highlight: Black-Right-Pointing-Pointer Ionothermal synthesis of BiOBr microspheres with hierarchical structure. Black-Right-Pointing-Pointer Efficient mass transfer and excellent light-harvesting ability. Black-Right-Pointing-Pointer Suitable for removing heavy metals and treatment of organic dyes. Black-Right-Pointing-Pointer Remarkable photocatalytic bactericidal property. - Abstract: Bismuth oxybromide (BiOBr) micropsheres with hierarchical morphologies have been fabricated via an ionothermal synthesis route. Ionic liquid acts as a unique soft material capable of promoting nucleation and in situ growth of 3D hierarchical BiOBr mesocrystals without the help of surfactants. The as-prepared BiOBr nanomaterials can effectively remove heavy metal ions and organic dyes from wastewater. They can also kill Micrococcus lylae, a Gram positive bacterium, in water under fluorescent light irradiation. Their high adaptability in water treatment may be ascribed to their hierarchical structure, allowing them high surface to volume ratio, facile species transportation and excellent light-harvesting ability.

Ionothermal synthesis of hierarchical BiOBr microspheres for water treatment

International Nuclear Information System (INIS)

Zhang, Dieqing; Wen, Meicheng; Jiang, Bo; Li, Guisheng; Yu, Jimmy C.

2012-01-01

Graphical abstract: Hierarchical BiOBr microspheres were prepared from a bromine-containing ionic liquid. The material was found effective for removing heavy metals, degrading organic pollutants and killing bacteria. Highlight: ► Ionothermal synthesis of BiOBr microspheres with hierarchical structure. ► Efficient mass transfer and excellent light-harvesting ability. ► Suitable for removing heavy metals and treatment of organic dyes. ► Remarkable photocatalytic bactericidal property. - Abstract: Bismuth oxybromide (BiOBr) micropsheres with hierarchical morphologies have been fabricated via an ionothermal synthesis route. Ionic liquid acts as a unique soft material capable of promoting nucleation and in situ growth of 3D hierarchical BiOBr mesocrystals without the help of surfactants. The as-prepared BiOBr nanomaterials can effectively remove heavy metal ions and organic dyes from wastewater. They can also kill Micrococcus lylae, a Gram positive bacterium, in water under fluorescent light irradiation. Their high adaptability in water treatment may be ascribed to their hierarchical structure, allowing them high surface to volume ratio, facile species transportation and excellent light-harvesting ability.

BiOCl nanowire with hierarchical structure and its Raman features

International Nuclear Information System (INIS)

Tian Ye; Guo Chuanfei; Guo Yanjun; Wang Qi; Liu Qian

2012-01-01

BiOCl is a promising V-VI-VII-compound semiconductor with excellent optical and electrical properties, and has great potential applications in photo-catalysis, photoelectric, etc. We successfully synthesize BiOCl nanowire with a hierarchical structure by combining wet etch (top-down) with liquid phase crystal growth (bottom-up) process, opening a novel method to construct ordered bismuth-based nanostructures. The morphology and lattice structures of Bi nanowires, β-Bi 2 O 3 nanowires and BiOCl nanowires with the hierarchical structure are investigated by scanning electron microscope (SEM) and transition electron microscope (TEM). The formation mechanism of such ordered BiOCl hierarchical structure is considered to mainly originate from the highly preferred growth, which is governed by the lattice match between (1 1 0) facet of BiOCl and (2 2 0) or (0 0 2) facet of β-Bi 2 O 3 . A schematic model is also illustrated to depict the formation process of the ordered BiOCl hierarchical structure. In addition, Raman properties of the BiOCl nanowire with the hierarchical structure are investigated deeply.

Superhydrophobic SERS substrates based on silicon hierarchical nanostructures

Science.gov (United States)

Chen, Xuexian; Wen, Jinxiu; Zhou, Jianhua; Zheng, Zebo; An, Di; Wang, Hao; Xie, Weiguang; Zhan, Runze; Xu, Ningsheng; Chen, Jun; She, Juncong; Chen, Huanjun; Deng, Shaozhi

2018-02-01

Silicon nanostructures have been cultivated as promising surface enhanced Raman scattering (SERS) substrates in terms of their low-loss optical resonance modes, facile functionalization, and compatibility with today’s state-of-the-art CMOS techniques. However, unlike their plasmonic counterparts, the electromagnetic field enhancements induced by silicon nanostructures are relatively small, which restrict their SERS sensing limit to around 10-7 M. To tackle this problem, we propose here a strategy for improving the SERS performance of silicon nanostructures by constructing silicon hierarchical nanostructures with a superhydrophobic surface. The hierarchical nanostructures are binary structures consisted of silicon nanowires (NWs) grown on micropyramids (MPs). After being modified with perfluorooctyltriethoxysilane (PFOT), the nanostructure surface shows a stable superhydrophobicity with a high contact angle of ˜160°. The substrate can allow for concentrating diluted analyte solutions into a specific area during the evaporation of the liquid droplet, whereby the analytes are aggregated into a small volume and can be easily detected by the silicon nanostructure SERS substrate. The analyte molecules (methylene blue: MB) enriched from an aqueous solution lower than 10-8 M can be readily detected. Such a detection limit is ˜100-fold lower than the conventional SERS substrates made of silicon nanostructures. Additionally, the detection limit can be further improved by functionalizing gold nanoparticles onto silicon hierarchical nanostructures, whereby the superhydrophobic characteristics and plasmonic field enhancements can be combined synergistically to give a detection limit down to ˜10-11 M. A gold nanoparticle-functionalized superhydrophobic substrate was employed to detect the spiked melamine in liquid milk. The results showed that the detection limit can be as low as 10-5 M, highlighting the potential of the proposed superhydrophobic SERS substrate in

Hierarchical structures of ZnO spherical particles synthesized solvothermally

Science.gov (United States)

Saito, Noriko; Haneda, Hajime

2011-12-01

We review the solvothermal synthesis, using a mixture of ethylene glycol (EG) and water as the solvent, of zinc oxide (ZnO) particles having spherical and flower-like shapes and hierarchical nanostructures. The preparation conditions of the ZnO particles and the microscopic characterization of the morphology are summarized. We found the following three effects of the ratio of EG to water on the formation of hierarchical structures: (i) EG restricts the growth of ZnO microcrystals, (ii) EG promotes the self-assembly of small crystallites into spheroidal particles and (iii) the high water content of EG results in hollow spheres.

Assessment of Morphological and Functional Changes in Organs of Rats after Intramuscular Introduction of Iron Nanoparticles and Their Agglomerates

Directory of Open Access Journals (Sweden)

Elena Sizova

2015-01-01

Full Text Available The research was performed on male Wistar rats based on assumptions that new microelement preparations containing metal nanoparticles and their agglomerates had potential. Morphological and functional changes in tissues in the injection site and dynamics of chemical element metabolism (25 indicators in body were assessed after repeated intramuscular injections (total, 7 with preparation containing agglomerate of iron nanoparticles. As a result, iron depot was formed in myosymplasts of injection sites. The quantity of muscle fibers having positive Perls’ stain increased with increasing number of injections. However, the concentration of the most chemical elements and iron significantly decreased in the whole skeletal muscle system (injection sites are not included. Consequently, it increased up to the control level after the sixth and the seventh injections. Among the studied organs (liver, kidneys, and spleen, Caspase-3 expression was revealed only in spleen. The expression had a direct dependence on the number of injections. Processes of iron elimination from preparation containing nanoparticles and their agglomerates had different intensity.

Effects of precursor on the morphology and size of ZrO{sub 2} nanoparticles, synthesized by sol-gel method in non-aqueous medium

Energy Technology Data Exchange (ETDEWEB)

Siddiqui, Mohammed Rafiq Hussain; Al-Wassil, Abdulaziz Ibrahim; Mahfouz, Refaat Mohamad [King Saud University, Riyadh (Saudi Arabia). Department of Chemistry, College of Science; Al-Otaibi, Abdullah Mohmmed [King Abdulaziz City for Science and Technology (Saudi Arabia). The NationalProgram for Advanced Materials and Building Systems

2012-11-15

Pure zirconium oxide (ZrO{sub 2}) nanoparticles with diameters 10-25 nm were synthesized from ZrOCl{sub 2}.8H{sub 2}O and Zr(SO{sub 4})2.H{sub 2}O with benzyl alcohol as non-aqueous solvent medium using sol-gel method. Sodium lauryl sulfate was added as surfactants to control the particle size. The synthesized ZrO{sub 2} nanoparticles have a mixture of tetragonal and monoclinic structure. The XRD showed the purity of obtained ZrO{sub 2} nanoparticles with tetragonal and monoclinic phase and the crystallite size for ZrOCl{sub 2}.8H{sub 2}O precursor was estimated to be 18.1 nm and that from Zr(SO{sub 4})2.H{sub 2}O was 9.7 nm. The transmission electron microscopy and scanning electron microscopic studies also shows different sizes of nanoparticles and different morphology depending on the precursor used for the synthesis of ZrO{sub 2} nanoparticles. (author)

Pt supported self-assembled nest-like-porous WO3 hierarchical microspheres as electrocatalyst for methanol oxidation

International Nuclear Information System (INIS)

Zhang, Jun; Tu, Jiang-ping; Du, Gao-hui; Dong, Zi-min; Su, Qing-mei; Xie, Dong; Wang, Xiu-li

2013-01-01

Highlights: ► Nest-like-porous (NLP) WO 3 microspheres are assembled by a hydrothermal method. ► The NLP-WO 3 microspheres have a hexagonal structure and high porous surface. ► Great enhancement of electrochemical property is achieved for Pt/NLP-WO 3 microspheres. -- Abstract: Hexagonal tungsten trioxide (hex-WO 3 ) hierarchical microspheres with nest-like pores are synthesized by a facile hydrothermal method. The nest-like-porous (NLP) WO 3 hierarchical microspheres with 5–6 μm in diameters are self-assembled of single-crystal nanowires. The nanowires have lengths of several hundred nanometers and diameters of 5–30 nm; the long axis of nanowire is oriented toward 〈0 0 1〉 direction. The specific surface area of hex-WO 3 microspheres is 62 m 2 g −1 . 20 wt.% Pt nanoparticles with ∼7 nm are loaded onto the WO 3 microspheres using a conventional microwave-assisted ethylene glycol (EG) method. The electrocatalytic activity for methanol oxidation of Pt/NLP-WO 3 microspheres is investigated by cyclic voltammetry and chronoamperometry. Due to the large tunnels of hexagonal structure and high porous surface morphology, great enhancement of electrochemical performance is achieved. The Pt/NLP-WO 3 microspheres are demonstrated to be a promising anode material for direct methanol fuel cells (DMFC)

A thermodynamics model for morphology prediction of aluminum nano crystals fabricated by the inert gas condensation method

Science.gov (United States)

Wen, Yu; Xia, Dehong

2018-03-01

The purpose of this study is to provide scientific guidance for the morphological control of nanoparticle synthesis using the gas phase method. A universal thermodynamics model is developed to predict the morphology of nanoparticles fabricated using the inert gas condensation method. By using this model, the morphologies of aluminum nanocrystals are predicted under various preparation conditions. There are two types of energy that jointly determine the formation of nanoparticle morphology—Gibbs free energy for nanoparticles and energy variation during the process. The results show that energy variation dominates morphology formation when the cooling rate is less than 2 × 1011 K s-1 in the aluminum nanocrystal production process. At the beginning of the nanoparticle growth, the most stable morphology is predicted to be spherical, but the energetically preferred morphology becomes cubic as the particle grows. The turning point in the particle size at which spherical morphology is no longer the most stable morphology is exhibited as a function of pressure in a condensation chamber for different cooling rates. In this paper, we focus on the need for morphology prediction based on preparation conditions. It is concluded that nanoparticles with various morphologies could be obtained by adjusting the cooling rate and pressure in the condensation chamber.

Molecular designing of nanoparticles and functional materials

Directory of Open Access Journals (Sweden)

Ignjatović Nenad L.

2017-01-01

Full Text Available The interdisciplinary research team implemented the program titled “Molecular designing of nanoparticles with controlled morphological and physicochemical characteristics and functional materials based on them” (MODENAFUNA, between 2011 and 2016, gaining new knowledge significant to the further improvement of nanomaterials and nanotechnologies. It gathered under its umbrella six main interrelated topics pertaining to the design and control of morphological and physicochemical properties of nanoparticles and functional material based on them using new methods of synthesis and processing: 1 inorganic nanoparticles, 2 cathode materials for lithium-ion batteries, 3 functional ceramics with improved electrical and optical properties, 4 full density nanostructured calcium phosphate and functionally-graded materials, 5 nano-calcium phosphate in bone tissue engineering and 6 biodegradable micro- and nano-particles for the controlled delivery of medicaments. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III45004: Molecular designing of nanoparticles with controlled morphological and physicochemical characteristics and functional materials based on them

Thin randomly aligned hierarchical carbon nanotube arrays as ultrablack metamaterials

Science.gov (United States)

De Nicola, Francesco; Hines, Peter; De Crescenzi, Maurizio; Motta, Nunzio

2017-07-01

Ultrablack metamaterials are artificial materials able to harvest all the incident light regardless of wavelength, angle, or polarization. Here, we show the ultrablack properties of randomly aligned hierarchical carbon nanotube arrays with thicknesses below 200 nm. The thin coatings are realized by solution processing and dry-transfer deposition on different substrates. The hierarchical surface morphology of the coatings is biomimetic and provides a large effective area that improves the film optical absorption. Also, such a morphology is responsible for the moth-eye effect, which leads to the omnidirectional and polarization-independent suppression of optical reflection. The films exhibit an emissivity up to 99.36% typical of an ideal black body, resulting in the thinnest ultrablack metamaterial ever reported. Such a material may be exploited for thermal, optical, and optoelectronic devices such as heat sinks, optical shields, solar cells, light and thermal sensors, and light-emitting diodes.

Pulsed electrodeposition of cobalt nanoparticles on copper: influence of the operating parameters on size distribution and morphology

International Nuclear Information System (INIS)

Pagnanelli, Francesca; Altimari, Pietro; Bellagamba, Marco; Granata, Giuseppe; Moscardini, Emanuela; Schiavi, Pier Giorgio; Toro, Luigi

2015-01-01

Cobalt nanoparticles were synthesized by pulsed electrodeposition on copper substrate. Scanning electron microscopy and image analysis were used to determine morphology and particle size distribution of nanoparticle populations obtained in different operating conditions. After preliminary tests, t on and t off were set at 50 and 300 ms respectively to obtain distinct nanoparticles and avoid dendritic structures. Experimental tests were performed according to two partially superimposed factorial designs with two factors at two levels. First factorial design investigated the effect of current density (I = 10 and 50 mA/cm 2 ) and discharged cobalt (Q = 2.5 × 10 −3 and 1.0 × 10 −2 C); second factorial design investigated the effect of cobalt concentration (C 0 = 0.01 and 0.1 M) for the same two levels of Q. For optimized value of t on /t off , square and hexagonal shaped nanoparticles were obtained. Statistical analysis evidenced that, for C 0 = 0.1 mol/L, current density is the most influencing factor on mean size: increasing I from 10 to 50 mA/cm 2 determined a diminution of mean size of 240 nm. For the same cobalt concentration, increasing the deposition time (Q) determined an increase of mean size of 60 nm. Diminishing the initial cobalt concentration from 0.1 to 0.01 mol/L determined an increase of mean size from 10 nm to 36 nm. For C 0 = 0.01 mol/L nanoparticles grow reaching an optimal size (36 nm) and then, increasing the time of deposition, optimal sized subunits tend to aggregate. As for polydispersity of nanoparticles, statistical tests denoted that increasing I determined significant reduction of variance, while increasing the time of deposition determined a significant increase of variance

Morphological and cytohistochemical evaluation of renal effects of cadmium-doped silica nanoparticles given intratracheally to rat

International Nuclear Information System (INIS)

Coccini, T; Roda, E; Manzo, L; Barni, S

2013-01-01

Renal morphological parameters were determined in rats intratracheally instilled with model cadmium-containing silica nanoparticles (Cd-SiNPs, 1mg/rat), also exploring whether their potential modifications would be associated with toxicogenomic changes. Cd-SiNP effects, evaluated 7 and 30 days post-exposure, were assessed by (i) histopathology (Haematoxylin/Eosin Staining), (ii) characterization of apoptotic features by TUNEL staining. Data were compared with those obtained by CdCl 2 (400μg/rat), SiNPs (600μg/rat), 0.1 ml saline. Area-specific cell apoptosis was observed in all treatment groups: cortex and inner medulla were the most affected regions. Apoptotic changes were apparent at 7 days post-exposure in both areas, and were still observable in inner medulla 30 days after treatment. Increase in apoptotic frequency was more pronounced in Cd-SiNP-treated animals compared to either CdCl 2 or SiNPs. Histological findings showed comparable alterations in the renal glomerular (cortex) architecture occurring in all treatment groups at both time-points considered. The glomeruli appeared often collapsed, showing condensed, packed mesangial and endothelial cells. Oedematous haemorrhagic glomeruli were also observed in Cd-SiNPs-treated animals. Bare SiNPs caused morphological and apoptotic changes without modifying the renal gene expression profile. These findings support the concept that multiple assays and an integrated testing strategy should be recommended to characterize toxicological responses to nanoparticles in mammalian systems.

Morphological and cytohistochemical evaluation of renal effects of cadmium-doped silica nanoparticles given intratracheally to rat

Science.gov (United States)

Coccini, T.; Roda, E.; Barni, S.; Manzo, L.

2013-04-01

Renal morphological parameters were determined in rats intratracheally instilled with model cadmium-containing silica nanoparticles (Cd-SiNPs, 1mg/rat), also exploring whether their potential modifications would be associated with toxicogenomic changes. Cd-SiNP effects, evaluated 7 and 30 days post-exposure, were assessed by (i) histopathology (Haematoxylin/Eosin Staining), (ii) characterization of apoptotic features by TUNEL staining. Data were compared with those obtained by CdCl2 (400μg/rat), SiNPs (600μg/rat), 0.1 ml saline. Area-specific cell apoptosis was observed in all treatment groups: cortex and inner medulla were the most affected regions. Apoptotic changes were apparent at 7 days post-exposure in both areas, and were still observable in inner medulla 30 days after treatment. Increase in apoptotic frequency was more pronounced in Cd-SiNP-treated animals compared to either CdCl2 or SiNPs. Histological findings showed comparable alterations in the renal glomerular (cortex) architecture occurring in all treatment groups at both time-points considered. The glomeruli appeared often collapsed, showing condensed, packed mesangial and endothelial cells. Oedematous haemorrhagic glomeruli were also observed in Cd-SiNPs-treated animals. Bare SiNPs caused morphological and apoptotic changes without modifying the renal gene expression profile. These findings support the concept that multiple assays and an integrated testing strategy should be recommended to characterize toxicological responses to nanoparticles in mammalian systems.

Hierarchical architectures of ZnS–In2S3 solid solution onto TiO2 nanofibers with high visible-light photocatalytic activity

International Nuclear Information System (INIS)

Liu, Chengbin; Meng, Deshui; Li, Yue; Wang, Longlu; Liu, Yutang; Luo, Shenglian

2015-01-01

Graphical abstract: A unique hierarchical architecture of ZnS–In 2 S 3 solid solution onto TiO 2 nanofibers was fabricated. The hierarchical heterostructures exhibit high visible light photocatalytic activity and outstanding recycling performance. - Highlights: • Novel hierarchical heterostructure of TiO 2 @ZnS–In 2 S 3 solid solution. • Efficient inhibition of ZnS–In 2 S 3 solid solution aggregation. • High visible light photocatalytic activity. • Highly stable recycling performance. - Abstract: A unique hierarchical architecture of ZnS–In 2 S 3 solid solution nanostructures onto TiO 2 nanofibers (TiO 2 @ZnS–In 2 S 3 ) has been successfully fabricated by simple hydrothermal method. The ZnS–In 2 S 3 solid solution nanostructures exhibit a diversity of morphologies: nanosheet, nanorod and nanoparticle. The porous TiO 2 nanofiber templates effectively inhibit the aggregation growth of ZnS–In 2 S 3 solid solution. The formation of ZnS–In 2 S 3 solid solution is proved by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) and the intimate contact between TiO 2 nanofibers and ZnS–In 2 S 3 solid solution favors fast transfer of photogenerated electrons. The trinary TiO 2 @ZnS–In 2 S 3 heterostructures exhibit high adsorption capacity and visible light photocatalytic activity for the degradation of rhodamine B dye (RhB), remarkably superior to pure TiO 2 nanofibers or binary structures (ZnS/TiO 2 nanofibers, In 2 S 3 /TiO 2 nanofibers and ZnS–In 2 S 3 solid solution). Under visible light irradiation the RhB photocatalytic degradation rate over TiO 2 @ZnS–In 2 S 3 heterostructures is about 16.7, 12.5, 6.3, 5.9, and 2.2 times that over pure TiO 2 nanofibers, ZnS nanoparticles, In 2 S 3 /TiO 2 nanofibers, ZnS/TiO 2 nanofibers, and ZnS-In 2 S 3 solid solution, respectively. Furthermore, the TiO 2 @ZnS–In 2 S 3 heterostructures show highly stable recycling performance

Impact of Amorphous SiO{sub 2} Nanoparticles on a Living Organism: Morphological, Behavioral, and Molecular Biology Implications

Energy Technology Data Exchange (ETDEWEB)

Ambrosone, Alfredo; Scotto di Vettimo, Maria Rosaria [Istituto di Cibernetica “Eduardo Caianiello”, Consiglio Nazionale delle Ricerche, Pozzuoli (Italy); Malvindi, Maria Ada [Center for Biomolecular Nanotechnologies@UNILE, Istituto Italiano di Tecnologia, Arnesano (Italy); Roopin, Modi; Levy, Oren [The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan (Israel); Marchesano, Valentina [Istituto di Cibernetica “Eduardo Caianiello”, Consiglio Nazionale delle Ricerche, Pozzuoli (Italy); Pompa, Pier Paolo [Center for Biomolecular Nanotechnologies@UNILE, Istituto Italiano di Tecnologia, Arnesano (Italy); Tortiglione, Claudia; Tino, Angela, E-mail: a.tino@cib.na.cnr.it [Istituto di Cibernetica “Eduardo Caianiello”, Consiglio Nazionale delle Ricerche, Pozzuoli (Italy)

2014-09-29

It is generally accepted that silica (SiO{sub 2}) is not toxic. But the increasing use of silica nanoparticles (SiO{sub 2}NPs) in many different industrial fields has prompted the careful investigation of their toxicity in biological systems. In this report, we describe the effects elicited by SiO{sub 2}NPs on animal and cell physiology. Stable and monodisperse amorphous silica nanoparticles, 25 nM in diameter, were administered to living Hydra vulgaris (Cnidaria). The dose-related effects were defined by morphological and behavioral assays. The results revealed an all-or-nothing lethal toxicity with a rather high threshold (35 nM NPs) and a LT50 of 38 h. At sub lethal doses, the morphophysiological effects included: animal morphology alterations, paralysis of the gastric region, disorganization and depletion of tentacle specialized cells, increase of apoptotic and collapsed cells, and reduction of the epithelial cell proliferation rate. Transcriptome analysis (RNAseq) revealed 45 differentially expressed genes, mostly involved in stress response and cuticle renovation. Our results show that Hydra reacts to SiO{sub 2}NPs, is able to rebalance the animal homeostasis up to a relatively high doses of SiO{sub 2}NPs, and that the physiological modifications are transduced to gene expression modulation.

Titanium dioxide nanoparticles inhibit proliferation and induce morphological changes and apoptosis in glial cells

International Nuclear Information System (INIS)

Márquez-Ramírez, Sandra Gissela; Delgado-Buenrostro, Norma Laura; Chirino, Yolanda Irasema; Iglesias, Gisela Gutiérrez; López-Marure, Rebeca

2012-01-01

Titanium dioxide nanoparticles (TiO 2 NPs) are widely used in the chemical, electrical and electronic industries. TiO 2 NPs can enter directly into the brain through the olfactory bulb and be deposited in the hippocampus region. We determined the effect of TiO 2 NPs on rat and human glial cells, C6 and U373, respectively. We evaluated proliferation by crystal violet staining, internalization of TiO 2 NPs, and cellular morphology by TEM analysis, as well as F-actin distribution by immunostaining and cell death by detecting active caspase-3 and DNA fragmentation. TiO 2 NPs inhibited proliferation and induced morphological changes that were related with a decrease in immuno-location of F-actin fibers. TiO 2 NPs were internalized and formation of vesicles was observed. TiO 2 NPs induced apoptosis after 96 h of treatment. Hence, TiO 2 NPs had a cytotoxic effect on glial cells, suggesting that exposure to TiO 2 NPs could cause brain injury and be hazardous to health.

A study of some fundamental physicochemical variables on the morphology of mesoporous silica nanoparticles MCM-41 type

Science.gov (United States)

Beltrán-Osuna, Ángela A.; Gómez Ribelles, José L.; Perilla, Jairo E.

2017-12-01

All variables affecting the morphology of mesoporous silica nanoparticles (MSN) should be carefully analyzed in order to truly tailored design their mesoporous structure according to their final use. Although complete control on MCM-41 synthesis has been already claimed, reproducibility and repeatability of results remain a big issue due to the lack of information reported in literature. Stirring rate, reaction volume, and system configuration (i.e., opened or closed reactor) are three variables that are usually omitted, making the comparison of product characteristics difficult. Specifically, the rate of solvent evaporation is seldom disclosed, and its influence has not been previously analyzed. These variables were systematically studied in this work, and they were proven to have a fundamental impact on final particle morphology. Hence, a high degree of circularity ( C = 0.97) and monodispersed particle size distributions were only achieved when a stirring speed of 500 rpm and a reaction scale of 500 mL were used in a partially opened system, for a 2 h reaction at 80 °C. Well-shaped spherical mesoporous silica nanoparticles with a diameter of 95 nm, a pore size of 2.8 nm, and a total surface area of 954 m2 g-1 were obtained. Final characteristics made this product suitable to be used in biomedicine and nanopharmaceutics, especially for the design of drug delivery systems.

Bipyridine based metallogels: an unprecedented difference in photochemical and chemical reduction in the in situ nanoparticle formation.

Science.gov (United States)

Tatikonda, Rajendhraprasad; Bertula, Kia; Nonappa; Hietala, Sami; Rissanen, Kari; Haukka, Matti

2017-02-28

Metal co-ordination induced supramolecular gelation of low molecular weight organic ligands is a rapidly expanding area of research due to the potential in creating hierarchically self-assembled multi-stimuli responsive materials. In this context, structurally simple O-methylpyridine derivatives of 4,4'-dihydroxy-2,2'-bipyridine ligands are reported. Upon complexation with Ag(i) ions in aqueous dimethyl sulfoxide (DMSO) solutions the ligands spontaneously form metallosupramolecular gels at concentrations as low as 0.6 w/v%. The metal ions induce the self-assembly of three dimensional (3D) fibrillar networks followed by the spontaneous in situ reduction of the Ag-centers to silver nanoparticles (AgNPs) when exposed to daylight. Significant size and morphological differences of the AgNP's was observed between the standard chemical and photochemical reduction of the metallogels. The gelation ability, the nanoparticle formation and rheological properties were found to be depend on the ligand structure, while the strength of the gels is affected by the water content of the gels.

Photoresponsive Bridged Silsesquioxane Nanoparticles with Tunable Morphology for Light-Triggered Plasmid DNA Delivery

KAUST Repository

Fatieiev, Yevhen

2015-09-25

Bridged silsesquioxane nanocomposites with tunable morphologies incorporating o-nitrophenylene-ammonium bridges are described. The systematic screening of the sol-gel parameters allowed the material to reach the nanoscale –unlike most reported bridged silsesquioxane materials– with controlled dense and hollow structures of 100 to 200 nm. The hybrid composition of silsesquioxanes with 50% of organic content homogenously distributed in the nanomaterials endowed them with photoresponsive properties. Light irradiation was performed to reverse the surface charge of nanoparticles from +46 to -39 mV via the photoreaction of the organic fragments within the particles, as confirmed by spectroscopic monitorings. Furthermore, such NPs were ap-plied for the first time for the on-demand delivery of plasmid DNA in HeLa cancer cells via light actuation.

Photoresponsive Bridged Silsesquioxane Nanoparticles with Tunable Morphology for Light-Triggered Plasmid DNA Delivery

KAUST Repository

Fatieiev, Yevhen; Croissant, Jonas G.; Alsaiari, Shahad K.; Moosa, Basem; Anjum, Dalaver H.; Khashab, Niveen M.

2015-01-01

Bridged silsesquioxane nanocomposites with tunable morphologies incorporating o-nitrophenylene-ammonium bridges are described. The systematic screening of the sol-gel parameters allowed the material to reach the nanoscale –unlike most reported bridged silsesquioxane materials– with controlled dense and hollow structures of 100 to 200 nm. The hybrid composition of silsesquioxanes with 50% of organic content homogenously distributed in the nanomaterials endowed them with photoresponsive properties. Light irradiation was performed to reverse the surface charge of nanoparticles from +46 to -39 mV via the photoreaction of the organic fragments within the particles, as confirmed by spectroscopic monitorings. Furthermore, such NPs were ap-plied for the first time for the on-demand delivery of plasmid DNA in HeLa cancer cells via light actuation.

Automated morphological analysis of bone marrow cells in microscopic images for diagnosis of leukemia: nucleus-plasma separation and cell classification using a hierarchical tree model of hematopoesis

Science.gov (United States)

Krappe, Sebastian; Wittenberg, Thomas; Haferlach, Torsten; Münzenmayer, Christian

2016-03-01

The morphological differentiation of bone marrow is fundamental for the diagnosis of leukemia. Currently, the counting and classification of the different types of bone marrow cells is done manually under the use of bright field microscopy. This is a time-consuming, subjective, tedious and error-prone process. Furthermore, repeated examinations of a slide may yield intra- and inter-observer variances. For that reason a computer assisted diagnosis system for bone marrow differentiation is pursued. In this work we focus (a) on a new method for the separation of nucleus and plasma parts and (b) on a knowledge-based hierarchical tree classifier for the differentiation of bone marrow cells in 16 different classes. Classification trees are easily interpretable and understandable and provide a classification together with an explanation. Using classification trees, expert knowledge (i.e. knowledge about similar classes and cell lines in the tree model of hematopoiesis) is integrated in the structure of the tree. The proposed segmentation method is evaluated with more than 10,000 manually segmented cells. For the evaluation of the proposed hierarchical classifier more than 140,000 automatically segmented bone marrow cells are used. Future automated solutions for the morphological analysis of bone marrow smears could potentially apply such an approach for the pre-classification of bone marrow cells and thereby shortening the examination time.

Synthesis of hierarchical worm-like SnO{sub 2}@C aggregates and their enhanced lithium storage properties

Energy Technology Data Exchange (ETDEWEB)

Wu, Zhen-Guo [School of Chemical Engineering, SichuanUniversity, Chengdu 610065 (China); College of Energy, Xiamen University, Xiamen 361005 (China); Li, Jun-Tao, E-mail: jtli@xmu.edu.cn [College of Energy, Xiamen University, Xiamen 361005 (China); Zhong, Yan-Jun [School of Chemical Engineering, SichuanUniversity, Chengdu 610065 (China); College of Energy, Xiamen University, Xiamen 361005 (China); Liu, Jie [State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Guo, Xiao-Dong, E-mail: xiaodong2009@163.com [School of Chemical Engineering, SichuanUniversity, Chengdu 610065 (China); Huang, Ling [State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Zhong, Ben-He [School of Chemical Engineering, SichuanUniversity, Chengdu 610065 (China); Sun, Shi-Gang [College of Energy, Xiamen University, Xiamen 361005 (China); State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China)

2015-01-25

Highlights: • The hierarchical worm-like SnO{sub 2}@C aggregates were synthesized. • The hierarchical worm-like SnO{sub 2}@C unit is assembled by nanowires. • The cycling performances of SnO{sub 2}@C aggregates are improved. • A capacity of 477.0 mA h g{sup −1} at 400 mA g{sup −1} could be obtained after 60 cycles. - Abstract: The present paper reports a synthetic strategy of hierarchical worm-like SnO{sub 2}@C aggregates with enhanced electrochemical performances. Specifically, a glucose-assisted hydrothermal treatment of the intermediate Co–Sn alloy nanoparticles, which were formed by carbothermal reduction of mixed commercial SnO{sub 2} and Co{sub 3}O{sub 4} nanoparticles. The SnO{sub 2}@C sample exhibits enhanced cycling performance in comparison with raw commercial SnO{sub 2} nanoparticles and intermediate Co–Sn alloy nanoparticles when used as anode of lithium ion battery. A stable capacity of 533.6 mA h g{sup −1} at 100 mA g{sup −1} and 477.0 mA h g{sup −1} at 400 mA g{sup −1} remains after 60 cycles. When the current density increases to 1600 mA g{sup −1}, the SnO{sub 2}@C sample still deliver a high capacity of 384.2 mA h g{sup −1}. The superior electrochemical performances could be attributed to the synergistic effect of unique worm-like aggregates structure and carbon surface-layer, which facilitate the electron transportation and buffer the large volume change.

Incorporation of zinc oxide nanoparticles into chitosan-collagen 3D porous scaffolds: Effect on morphology, mechanical properties and cytocompatibility of 3D porous scaffolds.

Science.gov (United States)

Ullah, Saleem; Zainol, Ismail; Idrus, Ruszymah Hj

2017-11-01

The zinc oxide nanoparticles (particles size chitosan-collagen 3D porous scaffolds and investigated the effect of zinc oxide nanoparticles incorporation on microstructure, mechanical properties, biodegradation and cytocompatibility of 3D porous scaffolds. The 0.5%, 1.0%, 2.0% and 4.0% zinc oxide nanoparticles chitosan-collagen 3D porous scaffolds were fabricated via freeze-drying technique. The zinc oxide nanoparticles incorporation effects consisting in chitosan-collagen 3D porous scaffolds were investigated by mechanical and swelling tests, and effect on the morphology of scaffolds examined microscopically. The biodegradation and cytocompatibility tests were used to investigate the effects of zinc oxide nanoparticles incorporation on the ability of scaffolds to use for tissue engineering application. The mean pore size and swelling ratio of scaffolds were decreased upon incorporation of zinc oxide nanoparticles however, the porosity, tensile modulus and biodegradation rate were increased upon incorporation of zinc oxide nanoparticles. In vitro culture of human fibroblasts and keratinocytes showed that the zinc oxide nanoparticles facilitated cell adhesion, proliferation and infiltration of chitosan-collagen 3D porous scaffolds. It was found that the zinc oxide nanoparticles incorporation enhanced porosity, tensile modulus and cytocompatibility of chitosan-collagen 3D porous scaffolds. Copyright © 2017 Elsevier B.V. All rights reserved.

Facile synthesis of both needle-like and spherical hydroxyapatite nanoparticles: effect of synthetic temperature and calcination on morphology, crystallite size and crystallinity.

Science.gov (United States)

Wijesinghe, W P S L; Mantilaka, M M M G P G; Premalal, E V A; Herath, H M T U; Mahalingam, S; Edirisinghe, M; Rajapakse, R P V J; Rajapakse, R M G

2014-09-01

Synthetic hydroxyapatite (HA) nanoparticles, that mimic natural HA, are widely used as biocompatible coatings on prostheses to repair and substitute human bones. In this study, HA nanoparticles are prepared by precipitating them from a precursor solution containing calcium sucrate and ammonium dihydrogen orthophosphate, at a Ca/P mole ratio of 1.67:1, at temperatures, ranging from 10°C to 95°C. A set of products, prepared at different temperatures, is analyzed for their crystallinity, crystallite size, morphology, thermal stability and composition, by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopic techniques, while the other set is analyzed after calcining the respective products, soon after their synthesis, for 3h, at 700°C. The as-prepared products, after 2h of drying, without any calcination, are not crystalline, but they grow very slowly into needle-like morphologies, as they are ripened with time. The percentage crystallinity of the final products increases from 15% to 52%, with increasing the preparative temperature. The calcined samples always produce spherical nanoparticles of essentially the same diameter, between 90 nm and 100 nm, which does not change due to aging and preparative temperatures. Therefore, the same method can be utilized to synthesize both spherical and needle-like nanoparticles of hydroxyapatite, with well-defined sizes and shapes. The ability to use readily available cheap raw materials, for the synthesis of such well-defined crystallites of hydroxyapatite, is an added advantage of this method, which may be explored further for the scaling up of the procedures to suit to industrial scale synthesis of such hydroxyapatite nanoparticles. Copyright © 2014 Elsevier B.V. All rights reserved.

Nanoparticles of ZnO doped with Mn: structural and morphological characteristics

Energy Technology Data Exchange (ETDEWEB)

Bonifacio, Maria Aparecida Ribeiro; Lira, Helio de Lucena; Gama, Lucianna, E-mail: m_aparecidaribeiro@yahoo.com.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais; Neiva, Laedna Souto [Universidade Federal do Cariri (UFCA), Juazeiro do Norte, CE (Brazil). Unidade Academica de Materiais; Kiminami, Ruth H. G. A. [Universidade Federal de Sao Carlos (USCar), SP (Brazil). Departamento de Engenharia de Materiais

2017-07-15

In this study, the effects of dopant concentrations on the structural and morphological characteristics of Zn{sub 1-x}Mn{sub x} O powders (x= 0.025, 0.05, 0.075, and 0.1 mole) synthesized by the Pechini method has been investigated. The powder was characterized by X-ray diffraction (XRD), Brunauer-Emmet-Teller (BET) specific surface, energy dispersive X-ray (EDX), scanning electron microscopy (SEM) and Spectroscopy with Fourier transform (FTIR). An XRD analysis of the powder showed the formation of ZnO phase with a typical single phase wurtzite structure. The EDX analysis revealed Mn incorporated in the ZnO structure. The particle size calculated by BET ranged from 24 to 63 nm, confirming the nanometric size of the powder particles. The SEM analysis revealed irregular shaped particle agglomerates and the presence of nanosheets. From FTIR it was confirmed the wurtzite structure in ZnO and ZnO nanoparticles doped with Mn. (author)

Hierarchical porous ZnO microflowers with ultra-high ethanol gas-sensing at low concentration

Science.gov (United States)

Song, Liming; Yue, He; Li, Haiying; Liu, Li; Li, Yu; Du, Liting; Duan, Haojie; Klyui, N. I.

2018-05-01

Hierarchical porous and non-porous ZnO microflowers have been successfully fabricated by hydrothermal method. Their crystal structure, morphology and gas-sensing properties were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and chemical gas sensing intelligent analysis system (CGS). Compared with hierarchical non-porous ZnO microflowers, hierarchical porous ZnO microflowers exhibited ultra-high sensitivity with 50 ppm ethanol at 260 °C and the response is 110, which is 1.8 times higher than that of non-porous ZnO microflowers. Moreover, the lowest concentration limit of hierarchical porous ZnO microflowers (non-porous ZnO microflowers) to ethanol is 0.1 (1) ppm, the response value is 1.6 (1).

Effect of poly-α, γ, L-glutamic acid as a capping agent on morphology and oxidative stress-dependent toxicity of silver nanoparticles

Directory of Open Access Journals (Sweden)

Stevanović M

2011-11-01

Full Text Available Magdalena Stevanović1, Branimir Kovačević2, Jana Petković3, Metka Filipič3, Dragan Uskoković11Institute of Technical Sciences of Serbian Academy of Sciences and Arts, 2Institute of General and Physical Chemistry, Belgrade, Serbia; 3Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, SloveniaAbstract: Highly stable dispersions of nanosized silver particles were synthesized using a straightforward, cost-effective, and ecofriendly method. Nontoxic glucose was utilized as a reducing agent and poly- α, γ, L-glutamic acid (PGA, a naturally occurring anionic polymer, was used as a capping agent to protect the silver nanoparticles from agglomeration and render them biocompatible. Use of ammonia during synthesis was avoided. Our study clearly demonstrates how the concentration of the capping agent plays a major role in determining the dimensions, morphology, and stability, as well as toxicity of a silver colloidal solution. Hence, proper optimization is necessary to develop silver colloids of narrow size distribution. The samples were characterized by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, and zeta potential measurement. MTT assay results indicated good biocompatibility of the PGA-capped silver nanoparticles. Formation of intracellular reactive oxygen species was measured spectrophotometrically using 2,7-dichlorofluorescein diacetate as a fluorescent probe, and it was shown that the PGA-capped silver nanoparticles did not induce intracellular formation of reactive oxygen species.Keywords: silver nanoparticles, poly-α, γ, L-glutamic, green synthesis, morphology, cytotoxicity

A hypercrosslinking-induced self-assembly strategy for preparation of advanced hierarchical porous polymers with customizable functional components.

Science.gov (United States)

Xu, Hongji; Wu, Jinlun; Zheng, Bingna; Mai, Weicong; Xu, Fei; Chen, Luyi; Liu, Hao; Fu, Ruowen; Wu, Dingcai; Matyjaszewski, Krzysztof

2017-05-09

The fabrication of advanced hierarchical porous polymers with a unique 3D nanonetwork structure composed of functional core-microporous shell nanoparticles was reported based on the development of a simple and efficient hypercrosslinking-induced self-assembly strategy.

On the location, strength and accessibility of Brønsted acid sites in hierarchical ZSM-5 particles

DEFF Research Database (Denmark)

Tzoulaki, Despina; Jentys, Andreas; Pérez-Ramírez, Javier

2012-01-01

Microporous and mesoporous (hierarchical) ZSM-5 samples, prepared by desilication, dealumination and templating with carbon nanoparticles have been characterized by adsorbing benzene, cyclohexane and 1,3,5-trimethylbenzene (mesitylene) to probe the location, the strength and the accessibility...

Morphology evolution of ZrB2 nanoparticles synthesized by sol-gel method

International Nuclear Information System (INIS)

Zhang Yun; Li Ruixing; Jiang Yanshan; Zhao Bin; Duan Huiping; Li Junping; Feng Zhihai

2011-01-01

Zirconium diboride (ZrB 2 ) nanoparticles were synthesized by sol-gel method using zirconium n-propoxide (Zr(OPr) 4 ), boric acid (H 3 BO 3 ), sucrose (C 12 H 22 O 11 ), and acetic acid (AcOH). Clearly, it was a non-aqueous solution system at the very beginning of the reactions. Here, AcOH was used as both chemical modifier and solvent to control Zr(OPr) 4 hydrolysis. Actually, AcOH could dominate the hydrolysis by self-produced water of the chemical propulsion, rather than the help of outer water. C 12 H 22 O 11 was selected, since it can be completely decomposed to carbon. Thus, carbon might be accounted precisely for the carbothermal reduction reaction. Furthermore, we investigated the influence of the gelation temperature on the morphology of ZrB 2 particles. Increasing the gelation temperature, the particle shapes changed from sphere-like particles at 65 deg. C to a particle chain at 75 deg. C, and then form rod-like particles at 85 deg. C. An in-depth HRTEM observation revealed that the nanoparticles of ZrB 2 were gradually fused together to evolve into a particle chain, finally into a rod-like shape. These crystalline nature of ZrB 2 related to the gelation temperature obeyed the 'oriented attachment mechanism' of crystallography. - Graphical Abstract: Increasing the gelation temperature, the particle shapes changed from sphere-like particles at 65 deg. C to a particle chain at 75 deg. C, and then form rod-like particles at 85 deg. C. Highlights: → ZrB 2 nanoparticles were synthesized by sol-gel method in an non-aqueous solution system. → AcOH was used as both chemical modifier and solvent to control Zr(OPr) 4 hydrolysis. → C 12 H 22 O 11 was selected since it can be completely decomposed to carbon. → Increasing the gelation temperature, the particles changed from sphere-like to rod-like ones. → Crystalline nature of ZrB 2 obeyed the 'oriented attachment mechanism' of crystallography.

Impact of silica dioxide nanoparticles on the morphology of internal organs in rats by oral supplementation

Directory of Open Access Journals (Sweden)

N.V. Zaitseva

2016-12-01

Full Text Available The object of the study was amorphous silica dioxide (SiO 2 , which is widely used as a food additive (E551, a subsidiary component in pharmaceutical preparations, perfumery and cosmetic products etc. In the specification of JECFA silica dioxide does not have information about the size of its particles, which allows the use of fine amorphous SiO 2 , obtained by gas phase hydrolysis of tetrachlorosilane as a food additive. This material, known as the "Aerosil", is characterized by the size of the specific surface area of 300–380 m 2 /g and the size of its relatively weakly agglomerated particles of 6–30 nm, i.e., it is a nanomaterial. In the biological model the morphological changes in organs and tissue systems on oral supplementation of nanoscale particles of silica dioxide were studied. Wistar male rats were given nanosized silica dioxide with specific surface area of 300 m 2 /g and primary nanoparticle size on the basis of data of electrical, atomic-powered microscopy, and dynamic light scattering in the range of 20–60 nm during 92 days. Light microscopic morphological examination of organs of rats showed a relatively mild inflammation in the structure of parenchymal organs (liver, kidney, not showing a certain dose-dependent nanoparticles. The most pronounced changes were in ileum morphology, consisting of a massive lymph macrophage and eosinophil infiltration of villi, without any apparent violation of their epithelial layer structure, which indirectly indicates the absence of violations of the barrier function of the intestinal epithelium. At the maximum dose of 100 mg/kg bw, the increased immune response was the most significant in the wall of the ileum. The results indicate the potential risks to human health when using SiO 2 having a specific surface area of 300 m 2 /g or higher in the composition of food products as a food additive.

Effects of processing parameters on the morphology, structure, and magnetic properties of Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles synthesized with chemical methods

Energy Technology Data Exchange (ETDEWEB)

Ivantsov, R.D. [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Edelman, I.S., E-mail: ise@iph.krasn.ru [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Zharkov, S.M.; Velikanov, D.A. [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); Petrov, D.A. [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Ovchinnikov, S.G. [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); Lin, Chun-Rong [National Pingtung University, Pingtung City, Pingtung County, 90003, Taiwan (China); Li, Oksana [Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); National Pingtung University, Pingtung City, Pingtung County, 90003, Taiwan (China); Tseng, Yaw-Teng [National Pingtung University, Pingtung City, Pingtung County, 90003, Taiwan (China)

2015-11-25

Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles with x = 0, 0.2, and 0.4 were synthesized via thermal decomposition of metal nitrate or chloride salts and selenium powder using different precursor compositions and processing details. Single crystalline nano-belts or nano-rods coexist in the synthesized powder samples with hexagon-shaped plates in dependence on the precursor composition. The belts gathered into conglomerates forming “hierarchical” particles. Visible magnetic circular dichroism (MCD) of Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles embedded into a transparent matrix was investigated for the first time. The similarity of the MCD spectra of all samples showed the similarity of the nanoparticles electronic structure independent of their morphology. Basing on the MCD spectral maxima characteristics, electron transitions from the ground to the excited states were identified with the help of the conventional band theory and the multi-electron approach. - Highlights: • Single crystalline Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles with x = 0, 0.2, 0.4 were synthesized. • Correlation between synthesis conditions and nanoparticles morphology were obtained. • The nanoparticles magnetization behavior was studied. • Visible MCD of the Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles were studied for the first time.

Hierarchical thermoplastic rippled nanostructures regulate Schwann cell adhesion, morphology and spatial organization.

Science.gov (United States)

Masciullo, Cecilia; Dell'Anna, Rossana; Tonazzini, Ilaria; Böettger, Roman; Pepponi, Giancarlo; Cecchini, Marco

2017-10-12

Periodic ripples are a variety of anisotropic nanostructures that can be realized by ion beam irradiation on a wide range of solid surfaces. Only a few authors have investigated these surfaces for tuning the response of biological systems, probably because it is challenging to directly produce them in materials that well sustain long-term cellular cultures. Here, hierarchical rippled nanotopographies with a lateral periodicity of ∼300 nm are produced from a gold-irradiated germanium mold in polyethylene terephthalate (PET), a biocompatible polymer approved by the US Food and Drug Administration for clinical applications, by a novel three-step embossing process. The effects of nano-ripples on Schwann Cells (SCs) are studied in view of their possible use for nerve-repair applications. The data demonstrate that nano-ripples can enhance short-term SC adhesion and proliferation (3-24 h after seeding), drive their actin cytoskeleton spatial organization and sustain long-term cell growth. Notably, SCs are oriented perpendicularly with respect to the nanopattern lines. These results provide information about the possible use of hierarchical nano-rippled elements for nerve-regeneration protocols.

Nanomorphology Effects in Semiconductors with Native Ferromagnetism: Hierarchical Europium (II) Oxide Tubes Prepared via a Topotactic Nanostructure Transition.

Science.gov (United States)

Trepka, Bastian; Erler, Philipp; Selzer, Severin; Kollek, Tom; Boldt, Klaus; Fonin, Mikhail; Nowak, Ulrich; Wolf, Daniel; Lubk, Axel; Polarz, Sebastian

2018-01-01

Semiconductors with native ferromagnetism barely exist and defined nanostructures are almost unknown. This lack impedes the exploration of a new class of materials characterized by a direct combination of effects on the electronic system caused by quantum confinement effects with magnetism. A good example is EuO for which currently no reliable routes for nanoparticle synthesis can be established. Bottom-up approaches applicable to other oxides fail because of the labile oxidation state +II. Instead of targeting a direct synthesis, the two steps-"structure control" and "chemical transformation"-are separated. The generation of a transitional, hybrid nanophase is followed by its conversion into EuO under full conservation of all morphological features. Hierarchical EuO materials are now accessible in the shape of oriented nanodisks stacked to tubular particles. Magnetically, the coupling of either vortex or onion states has been found. An unexpected temperature dependence is governed by thermally activated transitions between these states. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tuning effect of polysaccharide Chitosan on structural, morphological, optical and photoluminescence properties of ZnO nanoparticles

Science.gov (United States)

Magesh, G.; Bhoopathi, G.; Nithya, N.; Arun, A. P.; Ranjith Kumar, E.

2018-05-01

Chitosan/ZnO nanocomposites was synthesized by in-situ chemical precipitation method. The effect of polysaccharide Chitosan concentration (0.1 g, 0.5 g, 1 g and 3 g) was investigated by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) with Energy dispersive spectroscopy (EDX), High Resolution Transmission Electron Microscopy (HRTEM), UV-visible (UV), Fourier Transform Infrared (FTIR) and Photoluminescence Spectroscopy (PL). XRD pattern confirms the hexagonal wurtzite structure of the Chitosan/ZnO nanocomposites. The structural morphology and the elemental composition of the samples were analysed by FESEM and EDX respectively. From TEM analysis, it is observed that the particles in spindle shape morphology with average particle size ranges 10-20 nm. UV-Vis analysis reveals that the Chitosan concentration affect the absorption band edge and shift towards lower wavelength. The oxygen vacancy induced photoluminescence of ZnO nanoparticles was observed and its intensity decreases by tuning the Chitosan concentration.

Bio-based synthesis of silver nanoparticles from orange waste: effects of distinct biomolecule coatings on size, morphology, and antimicrobial activity.

Science.gov (United States)

de Barros, Caio Henrique Nasi; Cruz, Guilherme Crispim Faria; Mayrink, Willian; Tasic, Ljubica

2018-01-01

Despite the numerous reports on biological syntheses of silver nanoparticles (AgNPs), little is known about the composition of their capping agents, protein corona of plant extract-mediated synthesis, and their influence on the properties of AgNPs. Here, orange ( Citrus sinensis ) waste was utilized as a source of an extract for AgNP synthesis (the protein corona composition of which was elucidated), and also as a starting material for hesperidin and nanocellulose extraction, which were used for bio-based AgNP synthesis. A comparison of the results using the two methods of synthesis is presented. AgNPs were synthesized using orange ( C. sinensis ) peel extract (Or-AgNPs) in a biological route, and using hesperidin (Hsd-AgNPs) and nanocellulose (extracted from oranges) in a green chemical route. Characterization of nanoparticles was carried out using zeta potential and hydrodynamic size measurements, transmission electron microscopy, and X-ray diffraction. Elucidation of proteins from protein corona was performed via ultra performance liquid chromatography-tandem mass spectrometer experiments. Antimicrobial activity was assessed via minimum inhibitory concentration assays against Xanthomonas axonopodis pv. citri ( Xac ), the bacterium that causes citric canker in oranges. Or-AgNPs were not completely uniform in morphology, having a size of 48.1±20.5 nm and a zeta potential of -19.0±0.4 mV. Stabilization was performed mainly by three proteins, which were identified by tandem mass spectrometry (MS/MS) experiments. Hsd-AgNPs were smaller (25.4±12.5 nm) and had uniform morphology. Nanocellulose provided a strong steric and electrostatic (-28.2±1.0 mV) stabilization to the nanoparticles. Both AgNPs presented roughly the same activity against Xac , with the minimum inhibitory concentration range between 22 and 24 μg mL -1 . Despite the fact that different capping biomolecules on AgNPs had an influence on morphology, size, and stability of AgNPs, the antibacterial

Trioctylphosphine-assisted morphology control of ZnO nanoparticles

Science.gov (United States)

Hong, Yun-Kun; Cho, GeonHee; Park, YoonSu; Oh, Soong Ju; Ha, Don-Hyung

2018-06-01

This study investigates the morphological change in colloidal ZnO nanoparticles (NPs) synthesized with trioctylphosphine (TOP). The addition of TOP to the synthesis causes an evolution in the shape of ZnO NPs to tadpole-like particles from quasi-spherical particles at 300 °C. The total length of the tadpole-like ZnO NPs can be modified by controlling the molar ratio of TOP to oleylamine (OLAM). The tadpole-like particles are elongated as the concentration of TOP increased but decreased when the addition of TOP is excessive. These tadpole-like ZnO NPs transform to quasi-spherical NPs regardless of the amount of TOP at a reaction time of 3 h at 300 °C. At 200 °C, the effect of TOP on the ZnO NP synthesis differs from that at 300 °C. The ZnO NPs synthesized by controlling the molar ratios of surfactant ligands (TOP:OLAM = 2:100 and 70:100) at 200 °C share similar amorphous structures, while a crystalline ZnO phase is formed when the reaction time is 3 h. X-ray photoelectron spectroscopy analysis shows that TOP influences the oxidation of ZnO and suggests that a combination of OLAM and TOP plays a role in controlling the shape of ZnO NPs. These results provide critical insights to the utilization of TOP for a shape controlling ligand in ZnO NPs and suggest a new route to design oxide NPs.

Bio-based synthesis of silver nanoparticles from orange waste: effects of distinct biomolecule coatings on size, morphology, and antimicrobial activity

Directory of Open Access Journals (Sweden)

Barros CHN

2018-03-01

Full Text Available Caio Henrique Nasi de Barros, Guilherme Crispim Faria Cruz, Willian Mayrink, Ljubica Tasic Laboratory of Chemical Biology, Department of Organic Chemistry, Instituto de Química da Universidade Estadual de Campinas–Unicamp, Campinas, SP, Brazil Purpose: Despite the numerous reports on biological syntheses of silver nanoparticles (AgNPs, little is known about the composition of their capping agents, protein corona of plant extract-mediated synthesis, and their influence on the properties of AgNPs. Here, orange (Citrus sinensis waste was utilized as a source of an extract for AgNP synthesis (the protein corona composition of which was elucidated, and also as a starting material for hesperidin and nanocellulose extraction, which were used for bio-based AgNP synthesis. A comparison of the results using the two methods of synthesis is presented. Methods: AgNPs were synthesized using orange (C. sinensis peel extract (­Or-AgNPs in a biological route, and using hesperidin (Hsd-AgNPs and nanocellulose (extracted from oranges in a green chemical route. Characterization of nanoparticles was carried out using zeta potential and hydrodynamic size measurements, transmission electron microscopy, and X-ray diffraction. Elucidation of proteins from protein corona was performed via ultra performance liquid chromatography-tandem mass spectrometer experiments. Antimicrobial activity was assessed via minimum inhibitory concentration assays against Xanthomonas axonopodis pv. citri (Xac, the bacterium that causes citric canker in oranges. Results: Or-AgNPs were not completely uniform in morphology, having a size of 48.1±20.5 nm and a zeta potential of −19.0±0.4 mV. Stabilization was performed mainly by three proteins, which were identified by tandem mass spectrometry (MS/MS experiments. Hsd-AgNPs were smaller (25.4±12.5 nm and had uniform morphology. Nanocellulose provided a strong steric and electrostatic (−28.2±1.0 mV stabilization to the nanoparticles

High surface area fibrous silica nanoparticles

KAUST Repository

Polshettiwar, Vivek; Basset, Jean-Marie

2014-01-01

Disclosed are high surface area nanoparticles that have a fibrous morphology. The nanoparticles have a plurality of fibers, wherein each fiber is in contact with one other fiber and each fiber has a length of between about 1 nm and about 5000 nm. Also disclosed are applications of the nanoparticles of the present invention, and methods of fabrication of the nanoparticles of the present invention.

High surface area fibrous silica nanoparticles

KAUST Repository

Polshettiwar, Vivek

2014-11-11

Disclosed are high surface area nanoparticles that have a fibrous morphology. The nanoparticles have a plurality of fibers, wherein each fiber is in contact with one other fiber and each fiber has a length of between about 1 nm and about 5000 nm. Also disclosed are applications of the nanoparticles of the present invention, and methods of fabrication of the nanoparticles of the present invention.

Synthesis of belt-like BiOBr hierarchical nanostructure with high photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Li, Haiping [National Engineering Technology Research Center for Colloidal Materials, Shandong University, Jinan 250100 (China); Liu, Jingyi; Hu, Tingxia [Environment Research Institute, Shandong University, Jinan 250100 (China); Du, Na; Song, Shue [Key Laboratory of Colloid and Interface Chemistry (Ministry of Education), Shandong University, Jinan 250100 (China); Hou, Wanguo, E-mail: wghou@sdu.edu.cn [Key Laboratory of Colloid and Interface Chemistry (Ministry of Education), Shandong University, Jinan 250100 (China)

2016-05-15

Highlights: • BiOBr hierarchical nanobelts (NBs) were solvothermally prepared. • NBs show higher specific surface area and photoabsorption than BiOBr nanosheets. • NBs exhibit higher photoactivity than the nanosheets. - Abstract: One-dimensional (1D) bismuth oxyhalide (BiOX) hierarchical nanostructures are always difficult to prepare. Herein, we report, for the first time, a simple synthesis of BiOBr nanobelts (NBs) via a facile solvothermal route, using bismuth subsalicylate as the template and bismuth source. The BiOBr nanobelts are composed of irregular single crystal nanoparticles with highly exposed (0 1 0) facets. Compared with the BiOBr nanosheets (NSs) with dominant exposed (0 0 1) facets, they exhibit higher photocatalytic activity toward degradation of Rhodamine B and Methylene Blue under visible light irradiation. The higher photocatalytic performance of BiOBr NBs arises from their larger specific surface area and higher photoabsorption capability. This study provides a simple route for synthesis of belt-like Bi-based hierarchical nanostructures.

Inorganic-Organic Thiol-ene Coated Mesh for Oil/Water Separation.

Science.gov (United States)

Chen, Qiyi; de Leon, Al; Advincula, Rigoberto C

2015-08-26

A highly efficient mesh for oil/water separation was fabricated by using a superhydrophobic and superoleophilic coating of thiol-ene hybrid, consisting of pentaerythritol tetra(3-mercaptopropionate) (PETMP), 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (TMTVSi), and hydrophobic fumed silica nanoparticles, via a simple two-step fabrication process. Spray deposition and UV curing photopolymerization were sequentially performed, during which solvent evaporation provides microscale roughness while nanoparticle aggregation forms nanoscale roughness. The hierarchical morphologies were stabilized after UV curing photopolymerization. High contact angle (>150°) and low roll-off angle (<5°) were achieved due to the multiscale roughness structure of the hierarchical morphologies. These coatings also have excellent chemical resistance, as well as temperature and pH stability, after curing.

Optimization of photoelectrochemical water splitting performance on hierarchical TiO 2 nanotube arrays

KAUST Repository

Zhang, Z.

2012-02-10

In this paper, we show that by varying the voltages during two-step anodization the morphology of the hierarchical top-layer/bottom-tube TiO 2 (TiO 2 NTs) can be finely tuned between nanoring/nanotube, nanopore/nanotube, and nanohole-nanocave/nanotube morphologies. This allows us to optimize the photoelectrochemical (PEC) water splitting performance on the hierarchical TiO 2 NTs. The optimized photocurrent density and photoconversion efficiency in this study, occurring on the nanopore/nanotube TiO 2 NTs, were 1.59 mA cm -2 at 1.23 V vs. RHE and 0.84% respectively, which are the highest values ever reported on pristine TiO 2 materials under illumination of AM 1.5G. Our findings contribute to further improvement of the energy conversion efficiency of TiO 2-based devices.

Optimization of photoelectrochemical water splitting performance on hierarchical TiO 2 nanotube arrays

KAUST Repository

Zhang, Z.; Wang, Peng

2012-01-01

In this paper, we show that by varying the voltages during two-step anodization the morphology of the hierarchical top-layer/bottom-tube TiO 2 (TiO 2 NTs) can be finely tuned between nanoring/nanotube, nanopore/nanotube, and nanohole-nanocave/nanotube morphologies. This allows us to optimize the photoelectrochemical (PEC) water splitting performance on the hierarchical TiO 2 NTs. The optimized photocurrent density and photoconversion efficiency in this study, occurring on the nanopore/nanotube TiO 2 NTs, were 1.59 mA cm -2 at 1.23 V vs. RHE and 0.84% respectively, which are the highest values ever reported on pristine TiO 2 materials under illumination of AM 1.5G. Our findings contribute to further improvement of the energy conversion efficiency of TiO 2-based devices.

Hierarchical TiO{sub 2} submicron-sized spheres for enhanced power conversion efficiency in dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Wang, Hao [Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials and Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei University, Wuhan 430062 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Guo, Zhiguang, E-mail: zguo@licp.cas.cn [Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials and Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei University, Wuhan 430062 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2015-10-15

Hierarchical TiO{sub 2} submicron-sized sphere scattering layer, with relatively large surface area and effective light scattering, shows enhanced power conversion efficiency in dye-sensitized solar cells. - Highlights: • Hierarchical TiO{sub 2} submicron-sized spheres (TiO{sub 2} HSSs) with diameters of 400–600 nm were synthesized. • The HSSs composed of nanoparticles of ∼14 nm have a relatively large surface area of ∼35 m{sup 2}/g. • DSC exhibited the highest cell efficiency (6.23%) compared with ones with pure P25 (5.50%) or HSS (2.00%) photoanodes. - Abstract: Hierarchical TiO{sub 2} submicron-sized spheres (TiO{sub 2} HSSs) with diameters of 400–600 nm were synthesized by a facile one-step solvothermal method in ethanol solvent. The HSSs composed of nanoparticles of ∼14 nm have a relatively large surface area of ∼35 m{sup 2}/g. When applied as the scattering overlayer in dye-sensitized solar cells (DSCs), such TiO{sub 2} HSSs effectively improved light harvesting and led to the increase of photocurrent in DSCs. Furthermore, bilayer-structured photoanode also provided fast electron transportation and long electron lifetime as confirmed by electrochemical impedance spectra. As a result, DSC based on P25 nanoparticle underlayer and HSS-2 overlayer exhibited the highest cell efficiency (6.23%) compared with ones with pure P25 (5.50%) or HSS-2 (2.00%) photoanodes.

Hierarchically structured materials for lithium batteries

International Nuclear Information System (INIS)

Xiao, Jie; Zheng, Jianming; Li, Xiaolin; Shao, Yuyan; Zhang, Ji-Guang

2013-01-01

The lithium-ion battery (LIB) is one of the most promising power sources to be deployed in electric vehicles, including solely battery powered vehicles, plug-in hybrid electric vehicles, and hybrid electric vehicles. With the increasing demand for devices of high-energy densities (>500 Wh kg −1 ), new energy storage systems, such as lithium–oxygen (Li–O 2 ) batteries and other emerging systems beyond the conventional LIB, have attracted worldwide interest for both transportation and grid energy storage applications in recent years. It is well known that the electrochemical performance of these energy storage systems depends not only on the composition of the materials, but also on the structure of the electrode materials used in the batteries. Although the desired performance characteristics of batteries often have conflicting requirements with the micro/nano-structure of electrodes, hierarchically designed electrodes can be tailored to satisfy these conflicting requirements. This work will review hierarchically structured materials that have been successfully used in LIB and Li–O 2 batteries. Our goal is to elucidate (1) how to realize the full potential of energy materials through the manipulation of morphologies, and (2) how the hierarchical structure benefits the charge transport, promotes the interfacial properties and prolongs the electrode stability and battery lifetime. (paper)

Room temperature ferromagnetism in Mg-doped ZnO nanoparticles

International Nuclear Information System (INIS)

Singh, Jaspal; Vashihth, A.; Gill, Pritampal Singh; Verma, N. K.

2015-01-01

Zn 1-x Mg x O (x = 0, 0,10) nanoparticles were successfully synthesized using sol-gel method. X-ray diffraction (XRD) confirms that the synthesized nanoparticles possess wurtzite phase having hexagonal structure. Morphological analysis was carried out using transmission electron microscopy (TEM) which depicts the spherical morphology of ZnO nanoparticles. Energy dispersive spectroscopy (EDS) showed the presence of Mg in ZnO nanoparticles. Electron spin resonance (ESR) signal was found to be decreasing with increasing of Mg-doping concentration. The room temperature ferromagnetism was observed in undoped and Mg-doped ZnO nanoparticles. The increase of Mg-doping concentration resulted in decrease of saturation magnetization value which could be attributed to decrease of oxygen vacancies present in host nanoparticles

Hierarchical structure observation and nanoindentation size effect characterization for a limnetic shell

Science.gov (United States)

Song, Jingru; Fan, Cuncai; Ma, Hansong; Wei, Yueguang

2015-06-01

In the present research, hierarchical structure observation and mechanical property characterization for a type of biomaterial are carried out. The investigated biomaterial is Hyriopsis cumingii, a typical limnetic shell, which consists of two different structural layers, a prismatic "pillar" structure and a nacreous "brick and mortar" structure. The prismatic layer looks like a "pillar forest" with variation-section pillars sized on the order of several tens of microns. The nacreous material looks like a "brick wall" with bricks sized on the order of several microns. Both pillars and bricks are composed of nanoparticles. The mechanical properties of the hierarchical biomaterial are measured by using the nanoindentation test. Hardness and modulus are measured for both the nacre layer and the prismatic layer, respectively. The nanoindentation size effects for the hierarchical structural materials are investigated experimentally. The results show that the prismatic nanostructured material has a higher stiffness and hardness than the nacre nanostructured material. In addition, the nanoindentation size effects for the hierarchical structural materials are described theoretically, by using the trans-scale mechanics theory considering both strain gradient effect and the surface/interface effect. The modeling results are consistent with experimental ones.

Hierarchical ZnO particles grafting by fluorocarbon polymer derivative: Preparation and superhydrophobic behavior

Energy Technology Data Exchange (ETDEWEB)

Gao, Dahai; Jia, Mengqiu, E-mail: jiamq@mail.buct.edu.cn

2015-07-15

Graphical abstract: - Highlights: • The hierarchical particles were prepared by a simple, mild hydrothermal process. • The obtained “chestnut” ZnO particles show dual-scale morphology with high roughness. • FEVE derivative was creatively imported to graft onto hierarchical particles. • Superhydrophobic surfaces were obtained, on which the contact angles surpass 150°. • A special model was proposed to explain the wetting state in this work. - Abstract: Superhydrophobic surfaces on the basis of hierarchical ZnO particles grafted by fluoroethylene-vinylether (FEVE) polymer derivative were prepared using a facile, mild and low-cost method. X-ray diffraction (XRD) and scanning electron microscope (SEM) revealed that the resulting ZnO particles via hydrothermal process exhibit micro–nano dual-scale morphology with high purity under a suitable surfactant amount and alkali concentration. The grafting of FEVE derivative was confirmed by Fourier transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectrometer (EDS), suggesting that hierarchical surface of ZnO particles was an imported monomolecular layer of fluorocarbon polymer. The obtained surface fabricated by drop-casting shows considerably high contact angle and good resistance to water immersion. The wetting behavior in this work was furthermore analyzed by theoretical wetting model. This work demonstrates that the sufficient low-wettable surface and high roughness both take a vital role in the superhydrophobic behavior.

Fluorine- and iron-modified hierarchical anatase microsphere photocatalyst for water cleaning: facile wet chemical synthesis and wavelength-sensitive photocatalytic reactivity.

Science.gov (United States)

Liu, Shaohong; Sun, Xudong; Li, Ji-Guang; Li, Xiaodong; Xiu, Zhimeng; Yang, He; Xue, Xiangxin

2010-03-16

High photocatalytic efficiency, easy recovery, and no biological toxicity are three key properties related to the practical application of anatase photocatalyst in water cleaning, but seem to be incompatible. Nanoparticles-constructed hierarchical anatase microspheres with high crystallinity and good dispersion prepared in this study via one-step solution processing at 90 degrees C under atmospheric pressure by using ammonium fluotitanate as the titanium source and urea as the precipitant can reconcile these three requirements. The hierarchical microspheres were found to grow via an aggregative mechanism, and contact recrystallization occurred at high additions of the FeCl(3) electrolyte into the reaction system. Simultaneous incorporation of fluorine and iron into the TiO(2) matrix was confirmed by combined analysis of X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and UV-vis absorption spectroscopy. Surface structure and morphology changes of the microspheres induced by high-temperature annealing were clearly observed by field-emission scanning electron microscopy, especially for the phase-transformed particles. The original nanoparticles-constructed rough surfaces partially became smooth, resulting in a sharp drop in photocatalytic efficiency. Interestingly, iron loading has detrimental effects on the visible-light photocatalytic activity of both the as-prepared and the postannealed anatase microspheres but greatly enhances the photocatalytic activity of the as-prepared anatase microspheres under UV irradiation. No matter under UV or visible-light irradiation, the fluorine-loaded anatase microspheres and especially the postannealed ones show excellent photocatalytic performance. The underlying mechanism of fluorine and iron loading on the photocatalytic efficacy of the anatase microspheres was discussed in detail. Beyond photocatalytic applications, this kind of material is of great importance to the assembling of

Synthesis of hierarchically meso-macroporous TiO2/CdS heterojunction photocatalysts with excellent visible-light photocatalytic activity.

Science.gov (United States)

Zhao, Haixin; Cui, Shu; Yang, Lan; Li, Guodong; Li, Nan; Li, Xiaotian

2018-02-15

Photocatalysts with a hierarchically porous structure have attracted considerable attention owing to their wide pore size distribution and high surface area, which enhance the efficiency of transporting species to active sites. In this study, hierarchically meso-macroporous TiO 2 photocatalysts decorated with highly dispersed CdS nanoparticles were synthesized via hydrolysis, followed by a hydrothermal treatment. The textural mesopores and interconnected pore framework provided more accessible active sites and efficient mass transport for the photocatalytic process. The light collection efficiency was enhanced because of multiple scattering of incident light in the macropores. Moreover, the formation of a heterojunction between the CdS and TiO 2 nanoparticles extended the photoresponse of TiO 2 to the visible-light range and enhanced the charge separation efficiency. Therefore, the hierarchically meso-macroporous TiO 2 /CdS photocatalysts exhibited excellent photocatalytic activity for the degradation of rhodaming B under visible-light irradiation. Trapping experiments demonstrated that superoxide radicals (O 2 - ) and hydroxyl radicals (OH) were the main active species in photocatalysis. A reasonable photocatalytic mechanism of TiO 2 /CdS heterojunction photocatalysts was also presented. Copyright © 2017 Elsevier Inc. All rights reserved.

Nanoparticle-mediated nonclassical crystal growth of sodium fluorosilicate nanowires and nanoplates

Directory of Open Access Journals (Sweden)

Hongxia Li

2011-12-01

Full Text Available We observed nonclassical crystal growth of the sodium fluorosilicate nanowires, nanoplates, and hierarchical structures through self-assembly and aggregation of primary intermediate nanoparticles. Unlike traditional ion-by-ion crystallization, the primary nanoparticles formed first and their subsequent self-assembly, fusion, and crystallization generated various final crystals. These findings offer direct evidences for the aggregation-based crystallization mechanism.

Controllable fabrication of large-scale hierarchical silver nanostructures for long-term stable and ultrasensitive SERS substrates

Science.gov (United States)

Wu, Jing; Fang, Jinghuai; Cheng, Mingfei; Gong, Xiao

2016-09-01

In this work, we aim to prepare effective and long-term stable hierarchical silver nanostructures serving as surface-enhanced Raman scattering (SERS) substrates simply via displacement reaction on Aluminum foils. In our experiments, Hexadecyltrimethylammonium bromide (CTAB) is used as cationic surfactant to control the velocity of displacement reaction as well as the hierarchical morphology of the resultant. We find that the volume ratio of CTAB to AgNO3 plays a dominant role in regulating the hierarchical structures besides the influence of displacement reaction time. These as-prepared hierarchical morphologies demonstrate excellent SERS sensitivity, structural stability and reproducibility with low values of relative standard deviation less than 20 %. The high SERS analytical enhancement factor of ~6.7 × 108 is achieved even at the concentration of Crystal Violet (CV) as low as 10-7 M, which is sufficient for single-molecule detection. The detection limit of CV is 10-9 M in this study. We believe that this simple and rapid approach integrating advantages of low-cost production and high reproducibility would be a promising way to facilitate routine SERS detection and will get wide applications in chemical synthesis.

Morphology, thermoelectric properties and wet-chemical doping of laser-sintered germanium nanoparticles

International Nuclear Information System (INIS)

Stoib, Benedikt; Langmann, Tim; Matich, Sonja; Sachsenhauser, Matthias; Stutzmann, Martin; Brandt, Martin S.; Petermann, Nils; Wiggers, Hartmut

2013-01-01

Porous, highly doped semiconductors are potential candidates for thermoelectric energy conversion elements. We report on the fabrication of thin films of Ge via short-pulse laser-sintering of Ge nanoparticles (NPs) in vacuum and study the macroporous morphology of the samples by secondary electron microscopy (SEM) imaging. The temperature dependence of the electrical conductivity and the Seebeck coefficient of undoped Ge is discussed in conjunction with the formation of a defect band near the valence band. We further introduce a versatile method of doping the resulting films with a variety of common dopant elements in group-IV semiconductors by using a liquid containing the dopant atoms. This method is fully compatible with laser-direct writing and suited to fabricate small scale thermoelectric generators. The incorporation of the dopants is verified by X-ray photoelectron spectroscopy (XPS) and their electrical activation is studied by conductivity and thermopower measurements. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Nanoparticles in Polymers: Assembly, Rheology and Properties

Science.gov (United States)

Rao, Yuanqiao

Inorganic nanoparticles have the potential of providing functionalities that are difficult to realize using organic materials; and nanocomposites is an effective mean to impart processibility and construct bulk materials with breakthrough properties. The dispersion and assembly of nanoparticles are critical to both processibility and properties of the resulting product. In this talk, we will discuss several methods to control the hierarchical structure of nanoparticles in polymers and resulting rheological, mechanical and optical properties. In one example, polymer-particle interaction and secondary microstructure were designed to provide a low viscosity composition comprising exfoliated high aspect ratio clay nanoparticles; in another example, the microstructure control through templates was shown to enable unique thermal mechanical and optical properties. Jeff Munro, Stephanie Potisek, Phillip Hustad; all of the Dow Chemical Company are co-authors.

Construction of Hierarchical Polymer Brushes on Upconversion Nanoparticles via NIR-Light-Initiated RAFT Polymerization.

Science.gov (United States)

Xie, Zhongxi; Deng, Xiaoran; Liu, Bei; Huang, Shanshan; Ma, Pingan; Hou, Zhiyao; Cheng, Ziyong; Lin, Jun; Luan, Shifang

2017-09-13

Photoinduced reversible addition-fragmentation chain transfer (RAFT) polymerization generally adopts high-energy ultraviolet (UV) or blue light. In combination with photoredox catalyst, the excitation light wavelength was extended to the visible and even near-infrared (NIR) region for photoinduced electron transfer RAFT polymerization. In this report, we introduce for the first time a surface NIR-light-initiated RAFT polymerization on upconversion nanoparticles (UCNPs) without adding any photocatalyst and construct a functional inorganic core/polymer shell nanohybrid for application in cancer theranostics. The multilayer core-shell UCNPs (NaYF 4 :Yb/Tm@NaYbF 4 :Gd@NaNdF 4 :Yb@NaYF 4 ), with surface anchorings of chain transfer agents, can serve as efficient NIR-to-UV light transducers for initiating the RAFT polymerization. A hierarchical double block copolymer brush, consisting of poly(acrylic acid) (PAA) and poly(oligo(ethylene oxide)methacrylate-co-2-(2-methoxy-ethoxy)ethyl methacrylate) (PEG for short), was grafted from the surface in sequence. The targeting arginine-glycine-aspartic (RGD) peptide was modified at the end of the copolymer through the trithiolcarbonate end group. After loading of doxorubicin, the UCNPs@PAA-b-PEG-RGD exhibited an enhanced U87MG cancer cell uptake efficiency and cytotoxicity. Besides, the unique upconversion luminescence of the nanohybrids was used for the autofluoresence-free cell imaging and labeling. Therefore, our strategy verified that UCNPs could efficiently activate RAFT polymerization by NIR photoirradiation and construct the complex nanohybrids, exhibiting prospective biomedical applications due to the low phototoxicity and deep penetration of NIR light.

Influence of the surfactant and annealing rate on the morphology, magnetic and structural characteristics of Co2FeAl nanoparticles

International Nuclear Information System (INIS)

Pezeshki-Nejad, Zahra; Ramazani, Abdolali; Alikhanzadeh-Arani, Sima; Almasi-Kashi, Mohammad; Salavati-Niasari, Masoud

2016-01-01

This research focuses on the synthesis and characterization of the attractive magnetic alloys, full-Heusler Co 2 FeAl nanoparticles. A modified co-precipitation method has been developed in a template of chitosan biopolymer. XRD pattern of the product confirmed the high crystalline quality of the L2 1 ‒ordered nanoparticles, refined by Rietveld analysis. It was found that using different annealing rates can be surprisingly effective to achieve different morphologies from granular microstructure to fibrous-shaped nanostructure. Based on the obtained results of the high resolution TEM image, the presence of both populations of large single crystal grains and polycrystalline clusters containing several small particles (about 10 nm) can be found in the sample annealed up to 700 °C with 5 °C/min. This particle size distribution led to the co-existence of high and low coercive-field phases in the related FORC diagram. Major hysteresis loops showed that the using of chitosan biopolymer resulted in a smaller magnetic saturation compared to that of the control sample, probably due to presence of the oxide shell around the surface of nanoparticles when exposed to air. - Highlights: • First Order Reversal Curves (FORCs) analysis was used to study precisely. • A simple chemical process of co- precipitation rout was used for synthesizing the nanoparticles. • Well known chitosan biopolymer was used as polymer template for coating the nanoparticles. • Effects of the temperature and heating rate in the annealing process were investigated.

Layer-by-layer assembly of TiO(2) colloids onto diatomite to build hierarchical porous materials.

Science.gov (United States)

Jia, Yuxin; Han, Wei; Xiong, Guoxing; Yang, Weishen

2008-07-15

TiO(2) colloids with the most probably particle size of 10 nm were deposited on the surface of macroporous diatomite by a layer-by-layer (LBL) assembly method with using phytic acid as molecular binder. For preparation of colloidal TiO(2), titanium(IV) isopropoxide (Ti(C(3)H(7)O)(4)) was used as titanium precursor, nitric acid (HNO(3)) as peptizing agent and deionized water and isopropanol (C(3)H(7)OH) as solvent. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N(2) adsorption-desorption, and UV-vis spectra are used to assess the morphology and physical chemistry properties of the resulting TiO(2) coated diatomite. It was shown that the mesoporosity has been introduced into macroporous diatomite by LBL deposition. The mesoporosity was originated from close-packing of the uniform TiO(2) nanoparticles. More TiO(2) could be coated on the surface of diatomite by increasing the deposition cycles. This hierarchical porous material has potential for applications in catalytic reactions involved diffusion limit, especially in photocatalytic reactions.

Hierarchical ZnO/S,N:GQD composites: Biotemplated synthesis and enhanced visible-light-driven photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Cai, Aijun, E-mail: caiaijun80@163.com [College of Life Science and Technology, Hebei Normal University of Science & Technology, Qinhuangdao 066600 (China); College of Chemistry and Material Sciences, Hebei Normal University, Shijiazhuang 050016 (China); Wang, Xiuping, E-mail: wangxiuping0721@163.com [College of Life Science and Technology, Hebei Normal University of Science & Technology, Qinhuangdao 066600 (China); Qi, Yanling, E-mail: qyl6790@126.com [College of Life Science and Technology, Hebei Normal University of Science & Technology, Qinhuangdao 066600 (China); Ma, Zichuan, E-mail: mazc@vip.163.com [College of Chemistry and Material Sciences, Hebei Normal University, Shijiazhuang 050016 (China)

2017-01-01

Highlights: • ZnO/S,N:GQD composites were synthesized by using poplar leaves as biotemplates. • The composites have enhanced visible-light-driven photocatalytic activity. • The highly efficient charge separation of electron-hole pairs is achieved. • High surface areas play an important role in the photocatalysis. - Abstract: Graphene quantum dots co-doped with sulfur and nitrogen (S,N:GQDs) are successfully combined with leaf-templated ZnO nanoparticles (L-ZnO) to obtain hierarchical L-ZnO/S,N:GQD composites exhibiting highly surface area. The morphology, structure, and the visible-light-driven photocatalytic activity are investigated. Compared with non-templated ZnO/S,N:GQDs, L-ZnO/S,N:GQD composites exhibit higher photocatalytic activity for the degradation of rhodamine B under visible light irradiation. Such elevated photocatalytic activity results from two main effects: one is the highly effective charge separation in L-ZnO/S,N:GQD composites; the other is the high surface area, allowing for efficient capture of the visible light.

Substrate dependent hierarchical structures of RF sputtered ZnS films

Science.gov (United States)

Chalana, S. R.; Mahadevan Pillai, V. P.

2018-05-01

RF magnetron sputtering technique was employed to fabricate ZnS nanostructures with special emphasis given to study the effect of substrates (quartz, glass and quartz substrate pre-coated with Au, Ag, Cu and Pt) on the structure, surface evolution and optical properties. Type of substrate has a significant influence on the crystalline phase, film morphology, thickness and surface roughness. The present study elucidates the suitability of quartz substrate for the deposition of stable and highly crystalline ZnS films. We found that the role of metal layer on quartz substrate is substantial in the preparation of hierarchical ZnS structures and these structures are of great importance due to its high specific area and potential applications in various fields. A mechanism for morphological evolution of ZnS structures is also presented based on the roughness of substrates and primary nonlocal effects in sputtering. Furthermore, the findings suggest that a controlled growth of hierarchical ZnS structures may be achieved with an ordinary RF sputtering technique by changing the substrate type.

Structural and photovoltaic characteristics of hierarchical ZnO nanostructures electrodes

Energy Technology Data Exchange (ETDEWEB)

Saleem, Muhammad, E-mail: saleem.malikape@gmail.com [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Key Laboratory of Optoelectronic Technology and Systems of the Education Ministry of China, Chongqing University, Chongqing 400044 (China); Fang, L. [Key Laboratory of Optoelectronic Technology and Systems of the Education Ministry of China, Chongqing University, Chongqing 400044 (China); Shaukat, Saleem F.; Ahmad, M. Ashfaq [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Raza, Rizwan, E-mail: razahussaini786@gmail.com [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Akhtar, Majid Niaz; Jamil, Ayesha; Aslam, Samia [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Abbas, Ghazanfar [Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan)

2015-04-15

Highlights: • Hierarchically ZnO nanostructures electrodes were grown using hot plate magnetic stirring at different growth reaction temperature. • We have investigated the effect of working temperature of 160°, 170°, 180°, and 190° on the growth mechanism of nanospheres and on the power conversion efficiency of DSSCs. • ZnO nanospheres with perfect aggregation show superior power conversion efficiency of 1.24% which is about 83% higher than nanoparticles DSSC. • An obvious vogue is that the overall power conversion efficiency decreases as the degree of the spherical aggregation is gradually destroyed. - Abstract: Structural and photovoltaic characteristics of hierarchical ZnO nanostructures solar cell have been studied in relation to growth reaction temperature. It is found that the hierarchical ZnO nanostructures network to act not only as large surface area substrates but also as a transport medium for electrons injected from the dye molecules. The incident photon-to-current conversion efficiency is decreased by increasing the growth reaction temperature of ZnO electrodes. The best conversion efficiency of a 0.25 cm{sup 2} cell is measured to be 1.24% under 100 mW cm{sup −2} irradiation.

Structural and photovoltaic characteristics of hierarchical ZnO nanostructures electrodes

International Nuclear Information System (INIS)

Saleem, Muhammad; Fang, L.; Shaukat, Saleem F.; Ahmad, M. Ashfaq; Raza, Rizwan; Akhtar, Majid Niaz; Jamil, Ayesha; Aslam, Samia; Abbas, Ghazanfar

2015-01-01

Highlights: • Hierarchically ZnO nanostructures electrodes were grown using hot plate magnetic stirring at different growth reaction temperature. • We have investigated the effect of working temperature of 160°, 170°, 180°, and 190° on the growth mechanism of nanospheres and on the power conversion efficiency of DSSCs. • ZnO nanospheres with perfect aggregation show superior power conversion efficiency of 1.24% which is about 83% higher than nanoparticles DSSC. • An obvious vogue is that the overall power conversion efficiency decreases as the degree of the spherical aggregation is gradually destroyed. - Abstract: Structural and photovoltaic characteristics of hierarchical ZnO nanostructures solar cell have been studied in relation to growth reaction temperature. It is found that the hierarchical ZnO nanostructures network to act not only as large surface area substrates but also as a transport medium for electrons injected from the dye molecules. The incident photon-to-current conversion efficiency is decreased by increasing the growth reaction temperature of ZnO electrodes. The best conversion efficiency of a 0.25 cm 2 cell is measured to be 1.24% under 100 mW cm −2 irradiation

Synthesis and Characterization of Wooden Magnetic Activated Carbon Fibers with Hierarchical Pore Structures

Directory of Open Access Journals (Sweden)

Dongna Li

2018-04-01

Full Text Available Wooden magnetic activated carbon fibers (WMACFs with hierarchical pore structures were obtained by adding magnetic iron oxide (Fe3O4 nanoparticles into the liquefied wood. The structures and properties of WMACFs were analyzed by scanning electronmicroscopy (SEM, X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, N2 adsorption, and vibrating sample magnetometer (VSM. The results showed that WMACFs had high Brunauer-Emmett-Teller (BET surface area (1578 m2/g and total pore volume (0.929 cm3/g, of which 45% was the contribution of small mesopores of 2–3 nm. It is believed that Fe3O4 nanoparticles play an important role in the formation of hierarchical pores. With the Fe3O4 content increasing, the yield rate of WMACFs decreased, and the Fe3O4 crystal plane diffraction peaks and characteristic adsorption peaks were obviously observed. At the same time, it was also found that WMACFs had favorable magnetic properties when the Fe3O4 content was above 1.5%. As a result, WMACFs could be a promising candidate for high efficiency, low cost, and convenient separation for the magnetic field.

Synthesis of WO3 flower-like hierarchical architectures and their sensing properties

International Nuclear Information System (INIS)

Meng, Dan; Wang, Guosheng; San, Xiaoguang; Song, Yinmin; Shen, Yanbai; Zhang, Yajing; Wang, Kangjun; Meng, Fanli

2015-01-01

WO 3 flower-like hierarchical architectures were synthesized by hydrothermal process using sodium tungstate (Na 2 WO 4 ·2H 2 O) as tungsten source and citric acid (CA) as an assistant agent. The morphology and crystal structure were investigated using scanning electron microscope and X-ray diffractometer. It is found that CA played a significant role in governing morphologies of product during hydrothermal process. The obtained products were identified as triclinic crystal WO 3 structure. The ethanol gas sensing measurements showed that well-defined WO 3 flower-like structures synthesized at CA/W molar ratio of 1 with large specific surface area exhibited the higher responses compared with others at all operating temperatures. Moreover, the reversible and fast response to ethanol gas at various gas concentrations and good selectivity were obtained. The results indicated that the WO 3 flower-like hierarchical architectures are promising materials for gas sensors. - Highlights: • WO 3 flower-like structures were successfully synthesized by hydrothermal method. • The effect of citric acid amount on morphologies was investigated. • Good ethanol gas sensing properties of WO 3 flower-like structures were obtained

Photochemical transformation of silver nanoparticles by combining blue and green irradiation

Energy Technology Data Exchange (ETDEWEB)

Cardoso-Avila, P. E.; Pichardo-Molina, J. L., E-mail: jpichardo@cio.mx [Centro de Investigaciones en Optica A.C (Mexico); Krishna, C. Murali [Advanced Center for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Center (TMC) (India); Castro-Beltran, R. [Centro de Investigaciones en Optica A.C (Mexico)

2015-03-15

Spherical silver nanoparticles (diameter 3 nm) were transformed by means of photochemical synthesis using superluminescent LEDs. Flat rounded (21 nm) and decahedral nanoparticles (78 nm) were, respectively, obtained when the colloid was exposed to green and blue radiation. Furthermore, by changing from blue to green radiation at different exposure times, various morphologies and sizes were obtained. Exposure times shorter than 30 min of blue radiation followed by green radiation resulted on different morphologies such as twine rounded (42 nm), flat elongated (peanuts, 17 nm), and flat rounded nanoparticles (11 and 24 nm). Times longer than 45 min produced decahedral nanoparticles with corners ranging from rounded to sharp (size 71–78 nm). Additionally, these results showed that by controlling morphologies and sizes through the combination of blue and green light at different exposure times, it was possible to tune the plasmon band from 511 to 594 nm. Moreover, controlling the morphology of nanoparticles is of prime importance in order to exploit their properties as part of novel emerging technologies.

Hierarchical Bi{sub 2}WO{sub 6} architectures decorated with Pd nanoparticles for enhanced visible-light-driven photocatalytic activities

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jinniu; Chen, Tianhua [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710062 (China); Lu, Hongbing, E-mail: hblu@snnu.edu.cn [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710062 (China); Yang, Zhibo; Yin, Feng; Gao, Jianzhi; Liu, Qianru [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710062 (China); Tu, Yafang [Department of Physics, Institute for Interdisciplinary Research, Jianghan University, Wuhan, 430056 (China)

2017-05-15

Highlights: • A new kind of Pd decorated Bi{sub 2}WO{sub 6} hierarchical microarchitecture was synthesized. • Pd nanoparticles remarkably improved the photocatalytic activity of Bi{sub 2}WO{sub 6}. • The photo-generated holes and ·O{sub 2}{sup −} played a crucial role in the degradation of RhB. • The photocatalytic enhancement mechanism of the Pd-Bi{sub 2}WO{sub 6} composites was proposed. - Abstract: A new kind of hierarchical Pd-Bi{sub 2}WO{sub 6} architecture decorated with different molar ratios of Pd to Bi, has been fabricated by a hydrothermal process, followed by a chemical deposition method. The photocatalytic activities of the pure Bi{sub 2}WO{sub 6} and Pd-Bi{sub 2}WO{sub 6} nanocatalyst were examined in the degradation of Rhodamine B (RhB) dyes and phenol under visible light. The photocatalytic results showed that the Pd-Bi{sub 2}WO{sub 6} nanocomposites possessed observably enhanced photocatalytic activities. Particularly, the 2.0% Pd loaded Bi{sub 2}WO{sub 6} had the highest photocatalytic activity, exhibiting a nearly complete degradation of 30 mg/L RhB and 10 mg/L phenol within only 50 and 60 min, respectively. In addition, the trapping experiment results indicated that the photo-generated holes (h{sup +}) and ·O{sub 2}{sup −} played a crucial role in the degradation of RhB. According to the experimental results, the photocatalytic degradation mechanism of Pd-Bi{sub 2}WO{sub 6} was also proposed. The enhanced photocatalytic activities were ascribed to the combined effects of the highly efficient separation of electrons and holes, improved visible light utilization and increased BET specific surface areas of the Pd-Bi{sub 2}WO{sub 6} nanocomposites.

Morphological, structural and magnetic properties of α-Fe2O3 nanoparticles in an amorphous alumina matrix obtained by aqueous combustion method

International Nuclear Information System (INIS)

Tadic, Marin; Kusigerski, Vladan; Markovic, Dragana; Citakovic, Nada; Remskar, Maja; Spasojevic, Vojislav

2009-01-01

We report on morphological, structural and magnetic properties of α-Fe 2 O 3 nanoparticles in an amorphous alumina matrix synthesized by aqueous combustion method. The sample was characterized by X-ray powder diffraction (XRPD), high-resolution electron microscopy (HREM) and SQUID magnetometry. XRPD study reveals the phase purity of α-Fe 2 O 3 whereas HREM images show an unusual spongy structure and well-crystallized nanoparticles with a size of about 25 nm. Magnetic measurements show a high irreversibility temperature T irr ∼ 350 K, Morin transition at T M ∼ 210 K, increase of the magnetization below T ∼ 45 K and hysteretic behavior below T M at 5 K and 200 K.

Three-Dimensional ZnO Hierarchical Nanostructures: Solution Phase Synthesis and Applications

Directory of Open Access Journals (Sweden)

Xiaoliang Wang

2017-11-01

Full Text Available Zinc oxide (ZnO nanostructures have been studied extensively in the past 20 years due to their novel electronic, photonic, mechanical and electrochemical properties. Recently, more attention has been paid to assemble nanoscale building blocks into three-dimensional (3D complex hierarchical structures, which not only inherit the excellent properties of the single building blocks but also provide potential applications in the bottom-up fabrication of functional devices. This review article focuses on 3D ZnO hierarchical nanostructures, and summarizes major advances in the solution phase synthesis, applications in environment, and electrical/electrochemical devices. We present the principles and growth mechanisms of ZnO nanostructures via different solution methods, with an emphasis on rational control of the morphology and assembly. We then discuss the applications of 3D ZnO hierarchical nanostructures in photocatalysis, field emission, electrochemical sensor, and lithium ion batteries. Throughout the discussion, the relationship between the device performance and the microstructures of 3D ZnO hierarchical nanostructures will be highlighted. This review concludes with a personal perspective on the current challenges and future research.

Characterization of nanoparticles released during construction of photocatalytic pavements using engineered nanoparticles

International Nuclear Information System (INIS)

Dylla, Heather; Hassan, Marwa M.

2012-01-01

With the increasing use of titanium dioxide (TiO 2 ) nanoparticles in self-cleaning materials such as photocatalytic concrete pavements, the release of nanoparticles into the environment is inevitable. Nanoparticle concentration, particle size, surface area, elemental composition, and surface morphology are pertinent to determine the associated risks. In this study, the potential of exposure to synthetic nanoparticles released during construction activities for application of photocatalytic pavements was measured during laboratory-simulated construction activities of photocatalytic mortar overlays and in an actual field application of photocatalytic spray coat. A scanning mobility particle sizer system measured the size distribution of nanoparticles released during laboratory and field activities. Since incidental nanoparticles are released during construction activities, nanoparticle emissions were compared to those from similar activities without nano-TiO 2 . Nanoparticle counts and size distribution suggest that synthetic nanoparticles are released during application of photocatalytic pavements. In order to identify the nanoparticle source, nanoparticles were also collected for offline characterization using transmission electron microscopy. However, positive identification of synthetic nanoparticles was not possible due to difficulties in obtaining high-resolution images. As a result, further research is recommended to identify nanoparticle composition and sources.

Tuning structure of oppositely charged nanoparticle and protein complexes

Energy Technology Data Exchange (ETDEWEB)

Kumar, Sugam, E-mail: sugam@barc.gov.in; Aswal, V. K., E-mail: sugam@barc.gov.in [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Callow, P. [Institut Laue Langevin, DS/LSS, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)

2014-04-24

Small-angle neutron scattering (SANS) has been used to probe the structures of anionic silica nanoparticles (LS30) and cationic lyszyme protein (M.W. 14.7kD, I.P. ∼ 11.4) by tuning their interaction through the pH variation. The protein adsorption on nanoparticles is found to be increasing with pH and determined by the electrostatic attraction between two components as well as repulsion between protein molecules. We show the strong electrostatic attraction between nanoparticles and protein molecules leads to protein-mediated aggregation of nanoparticles which are characterized by fractal structures. At pH 5, the protein adsorption gives rise to nanoparticle aggregation having surface fractal morphology with close packing of nanoparticles. The surface fractals transform to open structures of mass fractal morphology at higher pH (7 and 9) on approaching isoelectric point (I.P.)

Structural and Morphological Properties of Nanostructured ZnO Particles Grown by Ultrasonic Spray Pyrolysis Method with Horizontal Furnace

Directory of Open Access Journals (Sweden)

G. Flores-Carrasco

2014-01-01

Full Text Available ZnO nanoparticles were synthesized in a horizontal furnace at 500°C using different zinc nitrate hexahydrate concentrations (0.01 and 0.1 M as reactive solution by ultrasonic spray pyrolysis method. The physical-chemical properties of synthesized ZnO nanoparticles have been characterized by thermogravimetric analysis (TGA, X-ray diffraction (XRD, scanning electron microscopy (SEM, energy dispersive spectroscopy (EDS, and high resolution transmission electron microscopy (HRTEM. With the TGA is has optimized the temperature at which the initial reactive (Zn(NO32·6H2O, is decomposed completely to give way to its corresponding oxide, ZnO. SEM revealed secondary particles with a quasispherical shape that do not change significantly with the increasing of precursor solution concentration as well as some content of the broken spheres. Increasing the precursor solution concentration leads to the increase in the average size of ZnO secondary particles from 248±73 to 470±160 nm; XRD reveals the similar tendency for the crystallite size which changes from 23±4 to 45±4 nm. HRTEM implies that the secondary particles are with hierarchical structure composed of primary nanosized subunits. These results showed that the precursor concentration plays an important role in the evolution on the size, stoichiometry, and morphology of ZnO nanoparticles.

Hierarchical assembly strategy and multiscale structural origin of exceptional mechanical performance in nacre

Science.gov (United States)

Huang, Zaiwang

Nacre (mother of pearl) is a self-assembled hierarchical nanocomposite in possession of exquisite multiscale architecture and exceptional mechanical properties. Previous work has shown that the highly-ordered brick-mortar-like structure in nacre is assembled via epitaxial growth and the aragonite platelets are pure single-crystals. Our results challenge this conclusion and propose that nacre's individual aragonite platelets are constructed with highly-aligned aragonite nanoparticles mediated by screw dislocation and amorphous aggregation. The underlying physics mechanism why the aragonite nanoparticles choose highly-oriented attachment as its crystallization pathway is rationalized in terms of thermodynamics. The aragonite nanoparticle order-disorder transformation can be triggered by high temperature and mechanical deformation, which in turn confirms that the aragonite nanoparticles are basic building blocks for aragonite platelets. Particularly fascinating is the fracture toughness enhancement of nacre through exquisitely collecting mechanically inferior calcium carbonate (CaCO3) and biomolecules. The sandwich-like microarchitecture with a geometrically staggered arrangement can induce crack deflection along its biopolymer interface, thus significantly enhancing nacre's fracture toughness. Our new findings ambiguously demonstrate that, aside from crack deflection, the advancing crack can invade aragonite platelet, leaving a zigzag crack propagation pathway. These unexpected experimental observations disclose, for the first time, the inevitable structural role of aragonite platelets in enhancing nacre's fracture toughness. Simultaneously, the findings that the crack propagates in a zigzag manner within individual aragonite platelets overturn the previously well-established wisdom that considers aragonite platelets as brittle single-crystals. Moreover, we investigated the dynamical mechanical response of nacre under unixial compression. Our results show that the

Bio-based synthesis of silver nanoparticles from orange waste: effects of distinct biomolecule coatings on size, morphology, and antimicrobial activity

Science.gov (United States)

de Barros, Caio Henrique Nasi; Cruz, Guilherme Crispim Faria; Mayrink, Willian; Tasic, Ljubica

2018-01-01

Purpose Despite the numerous reports on biological syntheses of silver nanoparticles (AgNPs), little is known about the composition of their capping agents, protein corona of plant extract-mediated synthesis, and their influence on the properties of AgNPs. Here, orange (Citrus sinensis) waste was utilized as a source of an extract for AgNP synthesis (the protein corona composition of which was elucidated), and also as a starting material for hesperidin and nanocellulose extraction, which were used for bio-based AgNP synthesis. A comparison of the results using the two methods of synthesis is presented. Methods AgNPs were synthesized using orange (C. sinensis) peel extract (Or-AgNPs) in a biological route, and using hesperidin (Hsd-AgNPs) and nanocellulose (extracted from oranges) in a green chemical route. Characterization of nanoparticles was carried out using zeta potential and hydrodynamic size measurements, transmission electron microscopy, and X-ray diffraction. Elucidation of proteins from protein corona was performed via ultra performance liquid chromatography-tandem mass spectrometer experiments. Antimicrobial activity was assessed via minimum inhibitory concentration assays against Xanthomonas axonopodis pv. citri (Xac), the bacterium that causes citric canker in oranges. Results Or-AgNPs were not completely uniform in morphology, having a size of 48.1±20.5 nm and a zeta potential of −19.0±0.4 mV. Stabilization was performed mainly by three proteins, which were identified by tandem mass spectrometry (MS/MS) experiments. Hsd-AgNPs were smaller (25.4±12.5 nm) and had uniform morphology. Nanocellulose provided a strong steric and electrostatic (−28.2±1.0 mV) stabilization to the nanoparticles. Both AgNPs presented roughly the same activity against Xac, with the minimum inhibitory concentration range between 22 and 24 μg mL−1. Conclusion Despite the fact that different capping biomolecules on AgNPs had an influence on morphology, size, and stability

Structure, morphology, and magnetic properties of Fe nanoparticles deposited onto single-crystalline surfaces

Directory of Open Access Journals (Sweden)

Armin Kleibert

2011-01-01

Full Text Available Background: Magnetic nanostructures and nanoparticles often show novel magnetic phenomena not known from the respective bulk materials. In the past, several methods to prepare such structures have been developed – ranging from wet chemistry-based to physical-based methods such as self-organization or cluster growth. The preparation method has a significant influence on the resulting properties of the generated nanostructures. Taking chemical approaches, this influence may arise from the chemical environment, reaction kinetics and the preparation route. Taking physical approaches, the thermodynamics and the kinetics of the growth mode or – when depositing preformed clusters/nanoparticles on a surface – the landing kinetics and subsequent relaxation processes have a strong impact and thus need to be considered when attempting to control magnetic and structural properties of supported clusters or nanoparticles.Results: In this contribution we focus on mass-filtered Fe nanoparticles in a size range from 4 nm to 10 nm that are generated in a cluster source and subsequently deposited onto two single crystalline substrates: fcc Ni(111/W(110 and bcc W(110. We use a combined approach of X-ray magnetic circular dichroism (XMCD, reflection high energy electron diffraction (RHEED and scanning tunneling microscopy (STM to shed light on the complex and size-dependent relation between magnetic properties, crystallographic structure, orientation and morphology. In particular XMCD reveals that Fe particles on Ni(111/W(110 have a significantly lower (higher magnetic spin (orbital moment compared to bulk iron. The reduced spin moments are attributed to the random particle orientation being confirmed by RHEED together with a competition of magnetic exchange energy at the interface and magnetic anisotropy energy in the particles. The RHEED data also show that the Fe particles on W(110 – despite of the large lattice mismatch between iron and tungsten – are

Pt hierarchical structure catalysts on BaTiO{sub 3}/Ti electrode for methanol and ethanol electrooxidations

Energy Technology Data Exchange (ETDEWEB)

Hu, Chenguo; He, Xiaoshan; Xia, Chuanhui [Department of Applied Physics, Chongqing University, Chongqing 400044 (China)

2010-03-15

Electrooxidations of methanol and ethanol have been investigated on different Pt catalytic titanium-supported electrodes in both acidic and alkaline media using cyclic voltammetry. BaTiO{sub 3} is used for the first time to make a nanoscaled roughness on the surface of Ti foil in order to effectively deposit Pt hierarchical structure and block foulness in solution reactions. The morphology of BaTiO{sub 3} nanocube on Ti foil, Pt catalysts deposited on BaTiO{sub 3}/Ti and Ti foil electrodes are characterized by field emission scanning electron microscopy. The results indicate that Pt nanoflowers can be effectively grown on the Ti foil covered with 1 {mu}m layer of BaTiO{sub 3} nanocubes and the catalytic oxidation behaviors to methanol and ethanol are much better than those of the Pt/Ti electrode as Pt nanoparticles can hardly be deposited on the smooth surface of the Ti foil. The Pt/BaTiO{sub 3}/Ti electrode could be adopted as excellent catalytic anode in fuel cells. (author)

Creating Hierarchical Pores by Controlled Linker Thermolysis in Multivariate Metal-Organic Frameworks.

Science.gov (United States)

Feng, Liang; Yuan, Shuai; Zhang, Liang-Liang; Tan, Kui; Li, Jia-Luo; Kirchon, Angelo; Liu, Ling-Mei; Zhang, Peng; Han, Yu; Chabal, Yves J; Zhou, Hong-Cai

2018-02-14

Sufficient pore size, appropriate stability, and hierarchical porosity are three prerequisites for open frameworks designed for drug delivery, enzyme immobilization, and catalysis involving large molecules. Herein, we report a powerful and general strategy, linker thermolysis, to construct ultrastable hierarchically porous metal-organic frameworks (HP-MOFs) with tunable pore size distribution. Linker instability, usually an undesirable trait of MOFs, was exploited to create mesopores by generating crystal defects throughout a microporous MOF crystal via thermolysis. The crystallinity and stability of HP-MOFs remain after thermolabile linkers are selectively removed from multivariate metal-organic frameworks (MTV-MOFs) through a decarboxylation process. A domain-based linker spatial distribution was found to be critical for creating hierarchical pores inside MTV-MOFs. Furthermore, linker thermolysis promotes the formation of ultrasmall metal oxide nanoparticles immobilized in an open framework that exhibits high catalytic activity for Lewis acid-catalyzed reactions. Most importantly, this work provides fresh insights into the connection between linker apportionment and vacancy distribution, which may shed light on probing the disordered linker apportionment in multivariate systems, a long-standing challenge in the study of MTV-MOFs.

Hierarchically Nanostructured Transition Metal Oxides for Lithium‐Ion Batteries

Science.gov (United States)

Zheng, Mingbo; Tang, Hao; Li, Lulu; Hu, Qin; Zhang, Li; Xue, Huaiguo

2018-01-01

Abstract Lithium‐ion batteries (LIBs) have been widely used in the field of portable electric devices because of their high energy density and long cycling life. To further improve the performance of LIBs, it is of great importance to develop new electrode materials. Various transition metal oxides (TMOs) have been extensively investigated as electrode materials for LIBs. According to the reaction mechanism, there are mainly two kinds of TMOs, one is based on conversion reaction and the other is based on intercalation/deintercalation reaction. Recently, hierarchically nanostructured TMOs have become a hot research area in the field of LIBs. Hierarchical architecture can provide numerous accessible electroactive sites for redox reactions, shorten the diffusion distance of Li‐ion during the reaction, and accommodate volume expansion during cycling. With rapid research progress in this field, a timely account of this advanced technology is highly necessary. Here, the research progress on the synthesis methods, morphological characteristics, and electrochemical performances of hierarchically nanostructured TMOs for LIBs is summarized and discussed. Some relevant prospects are also proposed. PMID:29593962

The influence of mannitol on morphology and disintegration of spray-dried nano-embedded microparticles.

Science.gov (United States)

Torge, Afra; Grützmacher, Philipp; Mücklich, Frank; Schneider, Marc

2017-06-15

Nano-embedded microparticles represent a promising approach to deliver nanoparticles to the lungs. Microparticles with an appropriate aerodynamic diameter enable an application by dry powder inhaler and the transport of nanoparticles into the airways. By disintegration after deposition, nanoparticles can be released to exhibit their advantages such as a sustained drug release and delivery of the drug across the mucus barrier. The use of an appropriate matrix excipient to embed the nanoparticles is essential for the necessary disintegration and release of nanoparticles. In this context we investigated the influence of mannitol on the morphology, aerodynamic properties and disintegration behavior of nano-embedded microparticles. PLGA nanoparticles and mannitol were spray dried each as sole component and in combination in three different ratios. An influence of the mannitol content on the morphology was observed. Pure mannitol microparticles were solid and spherical, while the addition of nanoparticles resulted in raisin-shaped hollow particles. The different morphologies can be explained by diffusion processes of the compounds described by the Péclet-number. All powders showed suitable aerodynamic properties. By dispersion of the powders in simulated lung fluid, initial nanoparticle sizes could be recovered for samples containing mannitol. The fraction of redispersed nanoparticles was increased with increasing mannitol content. To evaluate the disintegration under conditions with higher comparability to the in vivo situation, spray-dried powders were exposed to >90% relative humidity. The disintegration behavior was monitored by analyzing roughness values by white light interferometry and supporting SEM imaging. The exposure to high relative humidity was shown to be sufficient for disintegration of the microparticles containing mannitol, releasing morphologically unchanged nanoparticles. With increasing mannitol content, the disintegration occurred faster and to a

Solvothermal synthesis and analysis of Bi1-xSbx nanoparticles

International Nuclear Information System (INIS)

Sumithra, S.; Misra, D.K.; Wei, C.; Gabrisch, H.; Poudeu, P.F.P.; Stokes, K.L.

2011-01-01

Bismuth-antimony alloy nanoparticles have been synthesized by a facile solvothermal method using N,N-dimethylformamide and ethylene glycol as solvent/reducing agent; BiCl 3 , SbCl 3 and Bi(NO 3 ) 3 as precursors; and citric acid as a surface modifier/stabilizing agent. The particle size and size distribution of Bi nanoparticles were analyzed as a function of the synthesis conditions: molar ratio of precursor to surfactant, precursor concentration and reducing agent. Synthesis of Sb and Bi 0.88 Sb 0.12 under similar conditions was also investigated. The phase purity of nanoparticles was confirmed from X-ray diffraction and thermogravimetry and the nanoparticle morphology was investigated by transmission electron microscopy. A case study of Bi nanoparticles with detailed analysis of the particle morphology and size distribution of the nanoparticles is reported.

Synthesis of ZnO/CdSe hierarchical heterostructure with improved visible photocatalytic efficiency

International Nuclear Information System (INIS)

Wu, Yao; Xu, Fang; Guo, Defu; Gao, Zhiyong; Wu, Dapeng; Jiang, Kai

2013-01-01

ZnO/CdSe hierarchical heterostructure was prepared using pompon-like ZnO as substrate materials, and hexagonal CdSe nanoparticles were dispersed on the ZnO plates. The hybrid ZnO/CdSe samples were intensively investigated by XRD, SEM, TEM, HRTEM, PL and UV–vis absorption spectrum. The photocatalytic experiments confirm that ZnO/CdSe heterostructure exhibits improved photocatalytic efficiency compared to pure ZnO under visible light irradiation. CdSe nanoparticles are believed to serve as photosensitizers to extend the absorption spectrum to visible light region. In addition, the incorporation of CdSe can suppress the recombination of photogenerated electron-hole pairs, which contributes to the enhancement of photocatalytic efficiency.

Study of BSA protein adsorption/release on hydroxyapatite nanoparticles

Science.gov (United States)

Swain, Sanjaya Kumar; Sarkar, Debasish

2013-12-01

Three different spherical, rod and fibrous morphologies of hydroxyapatite (HA) nanoparticles have been prepared through control over the processing parameters like temperature, pH and Ca:P ratio. Protein adsorption/release with respect to HA nanoparticle morphologies are investigated using model protein bovine serum albumin (BSA). BSA adsorption on HA nanoparticles follows Langmuir adsorption isotherm. Thermal analysis and FT-IR spectrum confirms the BSA adhesion and retention of their secondary structure. High surface area with high Ca:P ratio nanorod adsorbs relatively more amount (28 mg BSA/gm of nanorod HA) of BSA within 48 h in comparison with counterpart fibroid and spherical morphologies. Slow and steady BSA release (75 wt% of adsorbed BSA in 96 h) from nanorod HA is found as futuristic drug delivery media.

Hierarchically porous micro-rod lithium-rich cathode material Li1.2Ni0.13Mn0.54Co0.13O2 for high performance lithium-ion batteries

International Nuclear Information System (INIS)

Zhang, Linjing; Borong, Wu.; Ning, Li.; Feng, Wu.

2014-01-01

Graphical abstract: - Highlights: • The hierarchically porous micro-rod Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 material is prepared by a facile hydrothermal method. • This material exhibits good cycling performance. • It delivers discharge capacities of 280.7, 254.8, 232.3, 225.6, 201.7 and 172.7 mAh g −1 at 0.1 C, 0.2 C, 0.5 C, 1 C, 2 C and 5 C rates, respectively. • Excellent rate capability and cycleability are obtained attributed to the hierarchically porous micro-rod structure. - Abstract: Lithium-rich cathode material Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 with hierarchically porous micro-rod structures has been synthesized using a facile hydrothermal method. The morphology and XRD patterns explain the formation mechanism of the sample. Micro-rod oxalates precursor with rough surface is formed during the hydrothermal reaction, and then the product with hierarchically porous structures constructed of nanoparticles is synthesized during the sintering process at high temperatures. The electrochemical performance results show that the as-prepared sample exhibits high capacities, good cycleability and outstanding rate capability. It delivers discharge capacities of 280.7, 254.8, 232.3, 225.6, 201.7 and 172.7 mAh g −1 at 0.1 C, 0.2 C, 0.5 C, 1 C, 2 C and 5 C rates, respectively. The cycle voltammograms indicate the good reversibility of the as-prepared Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 material. The high onset temperature of the exothermal peak in the differential scanning calorimetry curve implies its good thermal stability. The good performance of the as-prepared material is endowed by its hierarchically porous structures

Synthesis and Characterization of Hierarchical Structured TiO2 Nanotubes and Their Photocatalytic Performance on Methyl Orange

Directory of Open Access Journals (Sweden)

Kai Liu

2015-01-01

Full Text Available Hierarchical structured TiO2 nanotubes were prepared by mechanical ball milling of highly ordered TiO2 nanotube arrays grown by electrochemical anodization of titanium foil. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, specific surface area analysis, UV-visible absorption spectroscopy, photocurrent measurement, photoluminescence spectra, electrochemical impedance spectra, and photocatalytic degradation test were applied to characterize the nanocomposites. Surface area increased as the milling time extended. After 5 h ball milling, TiO2 hierarchical nanotubes exhibited a corn-like shape and exhibited enhanced photoelectrochemical activity in comparison to commercial P25. The superior photocatalytic activity is suggested to be due to the combined advantages of high surface area of nanoparticles and rapid electron transfer as well as collection of the nanotubes in the hierarchical structure. The hierarchical structured TiO2 nanotubes could be applied into flexible applications on solar cells, sensors, and other photoelectrochemical devices.

Uniform silver/polypyrrole core-shell nanoparticles synthesized by hydrothermal reaction

Energy Technology Data Exchange (ETDEWEB)

Wang Shibin [Department of Chemistry, Tsinghua University, Beijing 100084 (China); Shi Gaoquan [Department of Chemistry, Tsinghua University, Beijing 100084 (China)]. E-mail: gshi@tsinghua.edu.cn

2007-04-15

Uniformly sized silver/polypyrrole (Ag/PPy) core-shell nanoparticles were synthesized by one-step hydrothermal reaction of pyrrole and silver nitrate in the presence of polyvinyl pyrrolidone (PVP) as protection agent. The morphology and structures of the nanoparticles have been studied by scanning and transmission electronic microscopes, X-ray diffractometer and Raman spectroscopy. The experimental results indicated that the particles had 120 nm silver cores with 20 nm polypyrrole (PPy) coatings. The reaction conditions have strong effects on the morphology of the nanoparticles.

Uniform silver/polypyrrole core-shell nanoparticles synthesized by hydrothermal reaction

International Nuclear Information System (INIS)

Wang Shibin; Shi Gaoquan

2007-01-01

Uniformly sized silver/polypyrrole (Ag/PPy) core-shell nanoparticles were synthesized by one-step hydrothermal reaction of pyrrole and silver nitrate in the presence of polyvinyl pyrrolidone (PVP) as protection agent. The morphology and structures of the nanoparticles have been studied by scanning and transmission electronic microscopes, X-ray diffractometer and Raman spectroscopy. The experimental results indicated that the particles had 120 nm silver cores with 20 nm polypyrrole (PPy) coatings. The reaction conditions have strong effects on the morphology of the nanoparticles

Influence of the surfactant and annealing rate on the morphology, magnetic and structural characteristics of Co{sub 2}FeAl nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Pezeshki-Nejad, Zahra [Institute of Nano Science and Nano Technology, University of Kashan, P.O. Box. 87317–51167, Kashan, Islamic Republic of Iran (Iran, Islamic Republic of); Ramazani, Abdolali [Institute of Nano Science and Nano Technology, University of Kashan, P.O. Box. 87317–51167, Kashan, Islamic Republic of Iran (Iran, Islamic Republic of); Department of Physics, University of Kashan, 87317-51167, Kashan (Iran, Islamic Republic of); Alikhanzadeh-Arani, Sima [Institute of Nano Science and Nano Technology, University of Kashan, P.O. Box. 87317–51167, Kashan, Islamic Republic of Iran (Iran, Islamic Republic of); Almasi-Kashi, Mohammad [Institute of Nano Science and Nano Technology, University of Kashan, P.O. Box. 87317–51167, Kashan, Islamic Republic of Iran (Iran, Islamic Republic of); Department of Physics, University of Kashan, 87317-51167, Kashan (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Institute of Nano Science and Nano Technology, University of Kashan, P.O. Box. 87317–51167, Kashan, Islamic Republic of Iran (Iran, Islamic Republic of)

2016-08-15

This research focuses on the synthesis and characterization of the attractive magnetic alloys, full-Heusler Co{sub 2}FeAl nanoparticles. A modified co-precipitation method has been developed in a template of chitosan biopolymer. XRD pattern of the product confirmed the high crystalline quality of the L2{sub 1}‒ordered nanoparticles, refined by Rietveld analysis. It was found that using different annealing rates can be surprisingly effective to achieve different morphologies from granular microstructure to fibrous-shaped nanostructure. Based on the obtained results of the high resolution TEM image, the presence of both populations of large single crystal grains and polycrystalline clusters containing several small particles (about 10 nm) can be found in the sample annealed up to 700 °C with 5 °C/min. This particle size distribution led to the co-existence of high and low coercive-field phases in the related FORC diagram. Major hysteresis loops showed that the using of chitosan biopolymer resulted in a smaller magnetic saturation compared to that of the control sample, probably due to presence of the oxide shell around the surface of nanoparticles when exposed to air. - Highlights: • First Order Reversal Curves (FORCs) analysis was used to study precisely. • A simple chemical process of co- precipitation rout was used for synthesizing the nanoparticles. • Well known chitosan biopolymer was used as polymer template for coating the nanoparticles. • Effects of the temperature and heating rate in the annealing process were investigated.

Recycled hierarchical tripod-like CuCl from Cu-PCB waste etchant for lithium ion battery anode

Energy Technology Data Exchange (ETDEWEB)

Liu, Song [Faculty of Material Science and Engineering, Kunming University of Science and Technology, Kunming 650093 China (China); Hou, Hongying, E-mail: hongyinghou@kmust.edu.cn [Faculty of Material Science and Engineering, Kunming University of Science and Technology, Kunming 650093 China (China); Liu, Xianxi [Faculty of Mechanical and Electronic Engineering, Kunming University of Science and Technology, Kunming 650093 China (China); Duan, Jixiang; Yao, Yuan; Liao, Qishu; Li, Jing; Yang, Yunzhen [Faculty of Material Science and Engineering, Kunming University of Science and Technology, Kunming 650093 China (China)

2017-02-15

Highlights: • High EVA CuCl was recycled with 85% recovery from Cu-PCB waste etchant. • The recycled CuCl displayed a hierarchical tripod-like morphology. • The evolution mechanism of the recycled hierarchical CuCl crystal was proposed. • The corresponding discharge capacity in LIB was 201.4 mAh/g after 100 cycles. • The results shed a new light on resource recovery and environmental protection. - Abstract: Hierarchical CuCl with high economic value added (EVA) was successfully recycled with 85% recovery from the acid Cu printed circuit board (Cu-PCB) waste etchant via facile liquid chemical reduction. The micro-structure and morphology of the recycled hierarchical CuCl were systematically characterized in terms of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET). Furthermore, the corresponding electrochemical performances as lithium ion battery (LIB) anode were also investigated in terms of galvanostatic charge/discharge, cyclic voltammetry (CV) and AC impedance. As expected, the recycled CuCl displayed a hierarchical tripod-like structure and large specific surface area of 21.2 m{sup 2}/g. As the anode in LIB, the reversible discharge capacity was about 201.4 mAh/g even after 100 cycles, implying the satisfactory cycle performance. Clearly, the satisfactory results may open a new avenue to develop the sustainable industry, which is very important in terms of both the resource recovery and the environmental protection.

Ordered CdSe nanoparticles within self-assembled block copolymer domains on surfaces.

Science.gov (United States)

Zou, Shan; Hong, Rui; Emrick, Todd; Walker, Gilbert C

2007-02-13

Hierarchical, high-density, ordered patterns were fabricated on Si substrates by self-assembly of CdSe nanoparticles within approximately 20-nm-thick diblock copolymer films in a controlled manner. Surface-modified CdSe nanoparticles formed well-defined structures within microphase-separated polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) domains. Trioctylphosphine oxide (TOPO)-coated CdSe nanoparticles were incorporated into PS domains and polyethylene glycol-coated CdSe nanoparticles were located primarily in the P2VP domains. Nearly close-packed CdSe nanoparticles were clearly identified within the highly ordered patterns on Si substrates by scanning electron microscopy (SEM). Contact angle measurements together with SEM results indicate that TOPO-CdSe nanoparticles were partially placed at the air/copolymer interface.

Modelling of nanoparticles: approaches to morphology and evolution

International Nuclear Information System (INIS)

Barnard, A S

2010-01-01

As we learn more about the physics, chemistry and engineering of materials at the nanoscale, we find that the development of a complete understanding is not (in general) possible using one technique alone. Computer simulations provide a very valuable addition to our scientific repertoire, but it is not immediately intuitive which of the many methods available are right for a given problem. In this paper, various computational approaches are described as they apply to the study of the structure and formation of discrete inorganic nanoparticles. To illustrate how these methods are best used, results of studies from many research groups are reviewed, and informal case studies are constructed on carbon, titania and gold nanoparticles.

Assembling strategy to synthesize palladium modified kaolin nanocomposites with different morphologies

Science.gov (United States)

Li, Xiaoyu; Ouyang, Jing; Zhou, Yonghua; Yang, Huaming

2015-09-01

Nanocomposites of aluminosilicate minerals, kaolins (kaolinite and halloysite) with natural different morphologies assembling with palladium (Pd) nanoparticles have been successfully synthesized through strong electrostatic adsorption and chemical bonding after surface modification with 3-aminopropyl triethoxysilane (APTES). Meanwhile, the influence of different morphologies supports on catalytic hydrogenation properties was explored. The surface concentration of amino groups on the kaolins was related to the morphology and surface nature. Electronmicroscopy revealed that the monodisperse Pd nanoparticles were uniformly deposited onto the surface of kaolins, ranging in diameter from 0.5 nm to 5.5 nm. The functional groups could not only improve the dispersion of kaolins with different morphologies in solution, but also enhance the interaction between Pd precursors and kaolins, thus preventing small Pd nanoparticles from agglomerating and leading to high activity for the catalytic hydrogenation of styrene. Pd-FK@APTES was more active compared to other samples. Selecting the kaolin morphology with a different surface nature allows the selective surface modification of a larger fraction of the reactive facets on which the active sites can be enriched and tuned. This desirable surface coordination of catalytically active atoms could substantially improve catalytic activity.

Hierarchical Ag/AgCl-TiO{sub 2} hollow spheres with enhanced visible-light photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Wang, Xu Long; Yin, Hao Yong [College of Materials Environment Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Nie, Qiu Lin, E-mail: nieqiulin@hdu.edu.cn [College of Materials Environment Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Wu, Wei Wei [College of Materials Environment Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Zhang, Yang; LiYuan, Qiu [College of Science, Hangzhou Dianzi University, Hangzhou 310018 (China)

2017-01-01

The hierarchical Ag/AgCl-TiO{sub 2} hollow spheres were synthesized by depositing Ag/AgCl nanoparticles on TiO{sub 2} hollow spheres via a precipitation photoreduction method, and they were further characterized using TGA, SEM, TEM, XRD, XPS, UV–vis DRS and photoelectric chemical analysis. The analysis showed that the hierarchical Ag/AgCl-TiO{sub 2} hollow spheres exhibited the highest photocatalytic activity, which was approximately 13 times higher than that of TiO{sub 2} hollow spheres. The high photocatalytic activity of the composites is due to efficient electron-hole pairs separation at the photocatalyst interfaces, and localized surface plasmon resonance of Ag nanoparticles formed on AgCl particles in the degradation reaction. - Highlights: • TiO{sub 2} hollow spheres were prepared by a sacrificial template method. • The hollow spheres were modified with Ag/AgCl to form the heterojunctions. • The modification may produce synergistic effect of LSPR and hollow structure. • Visible light photocatalytic activity was enhanced on this hollow catalyst. • The mechanism of the improved photocatalytic performance was discussed.

Quantification of metallic nanoparticle morphology with tilt series imaging by transmission electron microscopy

Science.gov (United States)

Dutta, Aniruddha; Yuan, Biao; Clukay, Christopher J.; Grabill, Christopher N.; Heinrich, Helge; Bhattacharya, Aniket; Kuebler, Stephen M.

2012-02-01

We report on the quantitative analysis of electrolessly deposited Au and Ag nanoparticles (NPs) on SU8 polymer with the help of High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy (HAADF-STEM) in tilt series. Au NPs act as nucleating agents for the electroless deposition of silver. Au NPs were prepared by attachingAu^3+cations to amine functionalized SU8 polymeric surfaces and then reducing it with aqueous NaBH4. The nanoscale morphology of the deposited NPs on the surface of polymer has been studied from the dark field TEM cross sectional images. Ag NPs were deposited on the cross-linked polymeric surface from a silver citrate solution reduced by hydroquinone. HAADF-STEM enables us to determine the distances between the NPs and their exact locations at and near the surface. The particle distribution, sizes and densities provide us with the data necessary to control the parameters for the development of the electroless deposition technique for emerging nanoscale technologies.

Preparation of hierarchical β-Ni(OH)2 nanostructures and adsorption characterization of methyl orange dye

Science.gov (United States)

Jiao, Shujie; Jin, Yimin; Du, Qian; Zhu, Chunguang; Gao, Shiyong; Wang, Dongbo; Wang, Jinzhong

2018-05-01

The β-Ni(OH)2 nanostructures have been prepared by hydrothermal with ammonia as alkali source. The morphology of β-Ni(OH)2 evolves from hexagon sheets to flower-like hierarchical structure built up from the nanosheets as increasing the amount of ammonia. Hierarchical β-Ni(OH)2 nanostructures have strong adsorption effect on methyl orange dyes. The adsorption mechanism of β-Ni(OH)2 has been investigated, which could be expressed by pseudo-second order kinetic model with best match.

Directed self-assembly of nanoporous metallic- and bimetallic nanoparticle thin films

Energy Technology Data Exchange (ETDEWEB)

Pietsch, Torsten [Fachbereich Physik, Universitaet Konstanz (Germany); Gindy, Nabil; Fahmi, Amir [Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham (United Kingdom)

2010-07-01

Nanoporous thin films attracted considerable interest due to potential applications in optical coatings, catalysis, sensors as well as electronic devices. Recently, such films were prepared by post deposition treatments. The present study is focused on the fabrication of nanoporous thin films via directed self-assembly of hybrid materials. Due to the nature of this process no additional treatments are necessary to develop the pores. Hierarchical nanoporous structures are fabricated directly via deposition of polymer templated Au-nanoparticles onto hydrophilic substrates. These films exhibit two different pore diameters and a total pore density of more than 10{sup 10} holes per cm{sup 2}. Control over the pore size is achieved by changing the molecular weight of the PS-b-P4VP diblock copolymer. Moreover, the porous morphology is used as a template to fabricate bimetallic nanostructured thin films. Such well-defined nanostructures, not only exhibit unique physical properties but also provide control over the hydrophobicity of the coated surfaces.

Nanostructural evolution from nanosheets to one-dimensional nanoparticles for manganese oxide

International Nuclear Information System (INIS)

Pan, Hongmei; Kong, Xingang; Wen, Puhong; Kitayama, Tomonori; Feng, Qi

2012-01-01

Highlights: ► Nanosheets were transformed to other one-dimensional nanoparticles. ► Nanofibers, nanotubes, nanoribbons, and nanobelts were obtained. ► Nanoparticle morphology can be controlled with organic amines. ► Organic amines act as morphology directing agent. -- Abstract: This paper introduces a novel hydrothermal soft chemical synthesis process for manganese oxide nanostructured particles using two-dimensional manganese oxide nanosheets as precursor. In this process, a birnessite-type manganese oxide with a layered structure was exfoliated into its elementary layer nanosheets, and then the nanosheets were hydrothermally treated to transform the two-dimensional morphology of the nanosheets to one-dimensional nanoparticles. The manganese oxide nanofibers, nanotubes, nanobelts, nanoribbons, and fabric-ribbon-like particles constructed from nanofibers or nanobelts were obtained using this hydrothermal soft chemical process. The nanostructural evolution from the two-dimensional nanosheets to the one-dimensional nanoparticles was characterized by XRD, SEM, TEM, and TG-DTA analysis. The morphology and nanostructure of the products are strongly dependent on the molecular dimension of organic amine cations added in the reaction system. The organic amine cations act as a morphology directing agent in the nanostructural evolution process.

Hierarchically assembled DNA origami tubules with reconfigurable chirality

International Nuclear Information System (INIS)

Chen, Haorong; Cha, Tae-Gon; Pan, Jing; Choi, Jong Hyun

2013-01-01

The dynamic reconfiguration of a hierarchically assembled tubular structure is demonstrated using the DNA origami technique. Short cylindrical DNA origami monomers are synthesized and linked into elongated tubules, which can then be disassembled via toehold-mediated strand displacement. The disassembled subunits are subsequently linked into tubules of a different chirality. The reconfiguration is performed with the subunits carrying dumbbell hairpin DNA oligonucleotides or gold nanoparticles (AuNPs). The reconfiguration of higher order origami structures presented here is useful for constructing dynamic nanostructures that exceed the size limit of single DNA origami and may facilitate the study of molecular or particle interactions by tuning their relative distance and organization. (paper)

Gyrospun antimicrobial nanoparticle loaded fibrous polymeric filters

Energy Technology Data Exchange (ETDEWEB)

Eranka Illangakoon, U.; Mahalingam, S.; Wang, K. [Department of Mechanical Engineering, University College London, London WC1E 7JE (United Kingdom); Cheong, Y.-K. [School of Engineering and Technology, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Canales, E. [Department of Civil, Environmental and Geomatic Engineering, University College London, London WC1E 7JE (United Kingdom); Ren, G.G. [School of Engineering and Technology, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Cloutman-Green, E. [Department of Microbiology, Virology, and Infection Prevention Control, Great Ormond Street Hospital NHS Foundation Trust, London WCIN 3JH (United Kingdom); Edirisinghe, M., E-mail: m.edirisinghe@ucl.ac.uk [Department of Mechanical Engineering, University College London, London WC1E 7JE (United Kingdom); Ciric, L. [Department of Civil, Environmental and Geomatic Engineering, University College London, London WC1E 7JE (United Kingdom)

2017-05-01

A one step approach to prepare hybrid nanoparticle embedded polymer fibres using pressurised gyration is presented. Two types of novel antimicrobial nanoparticles and poly(methylmethacrylate) polymer were used in this work. X-ray diffraction analysis of the nanoparticles revealed Ag, Cu and W are the main elements present in them. The concentration of the polymer solution and the nanoparticle concentration had a significant influence on the fibre diameter, pore size and morphology. Fibres with a diameter in the range of 6–20 μm were spun using 20 wt% polymer solutions containing 0.1, 0.25 and 0.5 wt% nanoparticles under 0.3 MPa working pressure and a rotational speed of 36,000 rpm. Continuous, bead-free fibre morphologies were obtained for each case. The pore size in the fibres varied between 36 and 300 nm. Successful incorporation of the nanoparticles in polymer fibres was confirmed by energy dispersive x-ray analysis. The fibres were also gyrospun on to metallic discs to prepare filters which were tested for their antibacterial activity on a suspension of Pseudomonas aeruginosa. Nanoparticle loaded fibres showed higher antibacterial efficacy than pure poly(methylmethacrylate) fibres. - Highlights: • Nanoparticles containing Ag, Cu and W were studied for antimicrobial activity. • Hybrid nanoparticle-polymeric fibres were prepared using pressurised gyration. • Fibre characteristics were tailored using material and forming process variables. • Nanoparticle loaded fibre mats show higher antibacterial efficacy.

How viral capsids adapt to mismatched cargoes—identifying mechanisms of morphology control with simulations

Science.gov (United States)

Elrad, Oren

2009-03-01

During the replication of many viruses, hundreds to thousands of protein subunits assemble around the viral nucleic acid to form a protein shell called a capsid. Most viruses form one particular structure with astonishing fidelity; yet, recent experiments demonstrate that capsids can assemble with different sizes and morphologies to accommodate nucleic acids or other cargoes such as functionalized nanoparticles. In this talk, we will explore the mechanisms of simultaneous assembly and cargo encapsidation with a computational model that describes the assembly of icosahedral capsids around functionalized nanoparticles. With this model, we find parameter values for which subunits faithfully form empty capsids with a single morphology, but adaptively assemble into different icosahedral morphologies around nanoparticles with different diameters. Analyzing trajectories in which adaptation is or is not successful sheds light on the mechanisms by which capsid morphology may be controlled in vitro and in vivo, and suggests experiments to test these mechanisms. We compare the simulation results to recent experiments in which Brome Mosaic Virus capsid proteins assemble around functionalized nanoparticles, and describe how future experiments can test the model predictions.

Effect of zinc oxide nanoparticles synthesized by a precipitation

Indian Academy of Sciences (India)

ZnO nanoparticles were synthesized by a precipitation method in aqueous media from zinc nitrate hexahydrate and sodium hydroxide. The synthesized ZnO nanoparticles exhibited a crystalline structure with hexagonal structure of the wurtzite. The morphology of the synthesized ZnO nanoparticles presented a spherical ...

Biopolymeric nanoparticles

International Nuclear Information System (INIS)

Sundar, Sushmitha; Kundu, Joydip; Kundu, Subhas C

2010-01-01

This review on nanoparticles highlights the various biopolymers (proteins and polysaccharides) which have recently revolutionized the world of biocompatible and degradable natural biological materials. The methods of their fabrication, including emulsification, desolvation, coacervation and electrospray drying are described. The characterization of different parameters for a given nanoparticle, such as particle size, surface charge, morphology, stability, structure, cellular uptake, cytotoxicity, drug loading and drug release, is outlined together with the relevant measurement techniques. Applications in the fields of medicine and biotechnology are discussed along with a promising future scope. (topical review)

Hierarchically Ordered Nanopatterns for Spatial Control of Biomolecules

Science.gov (United States)

2015-01-01

The development and study of a benchtop, high-throughput, and inexpensive fabrication strategy to obtain hierarchical patterns of biomolecules with sub-50 nm resolution is presented. A diblock copolymer of polystyrene-b-poly(ethylene oxide), PS-b-PEO, is synthesized with biotin capping the PEO block and 4-bromostyrene copolymerized within the polystyrene block at 5 wt %. These two handles allow thin films of the block copolymer to be postfunctionalized with biotinylated biomolecules of interest and to obtain micropatterns of nanoscale-ordered films via photolithography. The design of this single polymer further allows access to two distinct superficial nanopatterns (lines and dots), where the PEO cylinders are oriented parallel or perpendicular to the substrate. Moreover, we present a strategy to obtain hierarchical mixed morphologies: a thin-film coating of cylinders both parallel and perpendicular to the substrate can be obtained by tuning the solvent annealing and irradiation conditions. PMID:25363506

Morphology and thin layer Investigation of metallic nanoparticles ...

Indian Academy of Sciences (India)

65

This preliminary research involved a new approach in characterization of ... Nanoparticles are currently used in many fields, including medicine, .... sensor surface improvement (e.g. nonpolar organic substances), this method used sensors,.

Novel hollow microspheres of hierarchical zinc-aluminum layered double hydroxides and their enhanced adsorption capacity for phosphate in water

International Nuclear Information System (INIS)

Zhou, Jiabin; Yang, Siliang; Yu, Jiaguo; Shu, Zhan

2011-01-01

Highlights: → Hierarchical Zn-Al LDHs hollow microspheres were first synthesized by a simple hydrothermal method using urea as precipitating agent. → The morphology of Zn-Al LDHs can be tailored from irregular platelet to hollow microspheres by simply varying concentrations of urea. → The as-prepared samples exhibit high adsorption capacity (54.1-232 mg/g) for phosphate from aqueous solution. - Abstract: Hollow microspheres of hierarchical Zn-Al layered double hydroxides (LDHs) were synthesized by a simple hydrothermal method using urea as precipitating agent. The morphology and microstructure of the as-prepared samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), nitrogen adsorption-desorption isotherms and fourier transform infrared (FTIR) spectroscopy. It was found that the morphology of hierarchical Zn-Al LDHs can be tuned from irregular platelets to hollow microspheres by simply varying concentrations of urea. The effects of initial phosphate concentration and contact time on phosphate adsorption using various Zn-Al LDHs and their calcined products (LDOs) were investigated from batch tests. Our results indicate that the equilibrium adsorption data were best fitted by Langmuir isothermal model, with the maximum adsorption capacity of 54.1-232 mg/g; adsorption kinetics follows the pseudo-second-order kinetic equation and intra-particle diffusion model. In addition, Zn-Al LDOs are shown to be effective adsorbents for removing phosphate from aqueous solutions due to their hierarchical porous structures and high specific surface areas.

Au-nanoparticles grafted on plasma treated PE

International Nuclear Information System (INIS)

Svorcik, V.; Chaloupka, A.; Rezanka, P.; Slepicka, P.; Kolska, Z.; Kasalkova, N.; Hubacek, T.; Siegel, J.

2010-01-01

Polyethylene (PE) surface was treated with Ar plasma. Activated surface was grafted from methanol solution of 1,2-ethanedithiol. Then the sample was immersed into freshly prepared colloid solution of Au-nanoparticles. Finally Au layer was sputtered on the samples. Properties of the modified PE were studied using various methods: AFM, EPR, RBS and nanoindentation. It was shown that the plasma treatment results in degradation of polymer chain (AFM) and creation of free radicals by EPR. After grafting with dithiol, the concentration of free radicals declines. The presence of Au and S in the surface layer after the coating with Au-nanoparticles was proved by RBS. Plasma treatment changes PE surface morphology and increases surface roughness, too. Another significant change in surface morphology and roughness was observed after deposition of Au-nanoparticles. Nanoindentation measurements show that the grafting with Au-nanoparticles increases adhesion of subsequently sputtered Au layer.

Microscopy of hierarchically organized TiO{sub 2} photoelectrode for dye solar cells

Energy Technology Data Exchange (ETDEWEB)

Eskandar, A., E-mail: aeska07@gmail.com [Department of Electrical and Electronics, Universiti Teknologi PETRONAS, Tronoh, Perak (Malaysia); Mohamed, N. M., E-mail: noranimuti-mohamed@petronas.com.my [Centre of Innovative Nanostructures and Nanodevices, Universiti Teknologi PETRONAS, Tronoh, Perak (Malaysia)

2015-07-22

Research on improving the performance of dye solar cells has various aspects of the device being investigated. This paper analyzes the deliberately hierarchized photoelectrode configuration for DSC applications to improve the performance of DSCs. Multiple layers of differently composed TiO{sub 2} particle types namely aggregates and nanoparticles were deposited to form a photoelectrode with thickness of about 12 µm. The photoelectrodes were assembled into working DSCs with an active area of 1 cm{sup 2}. Measurement for solar power conversion performance was measured under 1 sun at AM1.5 spectrum simulated sunlight. Electron microscopy for photoelectrode analysis was conducted using Field Emission Scattering Electron Microscopy with enhanced resolution. External Quantum Efficiency was measured using a purpose built instrument. Kinetics were investigated using the Electrochemical Impedance Spectroscopy (EIS) measurement with a potentiostat. The best performing DSC is of the hierarchically organized photoelectrode with a photoconversion efficiency of 4.58%, an increase of 14% in comparison to the reference samples with fully aggregates configuration. Short circuit current density, Jsc increases by about 2.223 mA cm{sup −2} relative to the blanks. The electron microscopy confirmed expected thickness at around 10 µm and layers forming the photoelectrode being hierarchically deposited with ∼20 nm TiO{sub 2} nanoparticles and 450 nm TiO{sub 2} aggregates mixture composition. EQE improved especially for visible region of 500-550 nm light wavelengths with 12 % increase in the response of in that region. Improvement to the diffusion coefficient as measured by the EIS contributed to the performance increase of the photoelectrode configuration under investigation.

Supercooled smectic nanoparticles

DEFF Research Database (Denmark)

Kuntsche, Judith; Koch, Michel H J; Fahr, Alfred

2009-01-01

Cholesteryl nonanoate (CN), myristate (CM), palmitate (CP) and oleate (CO) alone or in combination were evaluated as matrix lipids for the preparation of supercooled smectic nanoparticles with a high stability against recrystallization during storage. The phase behavior of the cholesterol esters......, laser diffraction combined with polarizing intensity differential scattering, DSC and SAXS. The morphology of selected formulations was studied by freeze-fracture electron microscopy. All smectic nanoparticles with a mixed cholesterol ester matrix were stable against recrystallization when stored...... at room temperature. Nanoparticles with a pure CN and mixed CM/CN matrix with a high fraction of CN (60% of the whole lipid matrix) could even be stored at 4 degrees C for at least 18 months without any recrystallization. As smectic nanoparticles are studied especially with regard to parenteral...

Aggregation in charged nanoparticles solutions induced by different interactions

Energy Technology Data Exchange (ETDEWEB)

Abbas, S.; Kumar, Sugam; Aswal, V. K., E-mail: vkaswal@barc.gov.in [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Kohlbrecher, J. [Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 PSI Villigen (Switzerland)

2016-05-23

Small-angle neutron scattering (SANS) has been used to study the aggregation of anionic silica nanoparticles as induced through different interactions. The nanoparticle aggregation is induced by addition of salt (NaCl), cationic protein (lysozyme) and non-ionic surfactant (C12E10) employing different kind of interactions. The results show that the interaction in presence of salt can be explained using DLVO theory whereas non-DLVO forces play important role for interaction of nanoparticles with protein and surfactant. The presence of salt screens the repulsion between charged nanoparticles giving rise to a net attraction in the DLVO potential. On the other hand, strong electrostatic attraction between nanoparticle and oppositely charged protein leads to protein-mediated nanoparticle aggregation. In case of non-ionic surfactant, the relatively long-range attractive depletion interaction is found to be responsible for the particle aggregation. Interestingly, the completely different interactions lead to similar kind of aggregate morphology. The nanoparticle aggregates formed are found to have mass fractal nature having a fractal dimension (~2.5) consistent with diffusion limited type of fractal morphology in all three cases.

Effect of poly-α, γ, L-glutamic acid as a capping agent on morphology and oxidative stress-dependent toxicity of silver nanoparticles

Science.gov (United States)

Stevanović, Magdalena; Kovačević, Branimir; Petković, Jana; Filipič, Metka; Uskoković, Dragan

2011-01-01

Highly stable dispersions of nanosized silver particles were synthesized using a straightforward, cost-effective, and ecofriendly method. Nontoxic glucose was utilized as a reducing agent and poly-α, γ, L-glutamic acid (PGA), a naturally occurring anionic polymer, was used as a capping agent to protect the silver nanoparticles from agglomeration and render them biocompatible. Use of ammonia during synthesis was avoided. Our study clearly demonstrates how the concentration of the capping agent plays a major role in determining the dimensions, morphology, and stability, as well as toxicity of a silver colloidal solution. Hence, proper optimization is necessary to develop silver colloids of narrow size distribution. The samples were characterized by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, and zeta potential measurement. MTT assay results indicated good biocompatibility of the PGA-capped silver nanoparticles. Formation of intracellular reactive oxygen species was measured spectrophotometrically using 2,7-dichlorofluorescein diacetate as a fluorescent probe, and it was shown that the PGA-capped silver nanoparticles did not induce intracellular formation of reactive oxygen species. PMID:22131829

Magnetite and magnetite/silver core/shell nanoparticles with diluted magnet-like behavior

International Nuclear Information System (INIS)

Garza-Navarro, Marco; Torres-Castro, Alejandro; Gonzalez, Virgilio; Ortiz, Ubaldo; De la Rosa, Elder

2010-01-01

In the present work is reported the use of the biopolymer chitosan as template for the preparation of magnetite and magnetite/silver core/shell nanoparticles systems, following a two step procedure of magnetite nanoparticles in situ precipitation and subsequent silver ions reduction. The crystalline and morphological characteristics of both magnetite and magnetite/silver core/shell nanoparticles systems were analyzed by high resolution transmission electron microscopy (HRTEM) and nanobeam diffraction patterns (NBD). The results of these studies corroborate the core/shell morphology and the crystalline structure of the magnetite core and the silver shell. Moreover, magnetization temperature dependent, M(T), measurements show an unusual diluted magnetic behavior attributed to the dilution of the magnetic ordering in the magnetite and magnetite/silver core/shell nanoparticles systems. - Graphical abstract: Biopolymer chitosan was used as stabilization media to synthesize both magnetite and magnetite/silver core/shell nanoparticles. Results of HRTEM and NBD patterns confirm core/shell morphology of the obtained nanoparticles. It was found that the composites show diluted magnet-like behavior.

Synthesis of Cu and Ce co-doped ZnO nanoparticles: crystallographic, optical, molecular, morphological and magnetic studies

Directory of Open Access Journals (Sweden)

Rawat Mohit

2017-07-01

Full Text Available In the present research work, crystallographic, optical, molecular, morphological and magnetic properties of Zn1-xCuxO (ZnCu and Zn1-x-yCeyCuxO (ZnCeCu nanoparticles have been investigated. Polyvinyl alcohol (PVA coated ZnCu and ZnCeCu nanoparticles have been synthesized by chemical sol-gel method and thoroughly studied using various characterization techniques. X-ray diffraction pattern indicates the wurtzite structure of the synthesized ZnCu and ZnCeCu particles. Transmission electron microscopy analysis shows that the synthesized ZnCu and ZnCeCu particles are of spherical shape, having average sizes of 27 nm and 23 nm, respectively. The incorporation of Cu and Ce in the ZnO lattice has been confirmed through Fourier transform infrared spectroscopy. Room temperature photoluminescence spectra of the ZnO doped with Cu and co-doped Ce display two emission bands, predominant ultra-violet near-band edge emission at 409.9 nm (3 eV and a weak green-yellow emission at 432.65 nm (2.27 eV. Room temperature magnetic study confirms the diamagnetic behavior of ZnCu and ferromagnetic behavior of ZnCeCu.

Effect of the hybrid composition on the physicochemical properties and morphology of iron oxide–gold nanoparticles

International Nuclear Information System (INIS)

Barnett, C. M.; Gueorguieva, M.; Lees, M. R.; McGarvey, D. J.; Darton, R. J.; Hoskins, C.

2012-01-01

Hybrid nanoparticles (HNPs) formed from iron oxide cores and gold nano-shells are becoming increasingly applicable in biomedicine. However, little investigation has been carried out on the effects of the constituent components on their physical characteristics. Here we determine the effect of polymer intermediate, gold nano-shell thickness and magnetic iron oxide core diameter on the morphological and physical properties of these nano-hybrids. Our findings suggest that the use of polymer intermediate directly impacts the morphology of the nanostructure formed. Here, we observed the formation of nano-sphere and nano-star structures by varying the cationic polymer intermediate. The nano-stars formed have a larger magnetic coercivity, T 2 relaxivity and exhibited a unique characteristic nano-heating pattern upon laser irradiation. Increasing the iron oxide core diameter resulted in a greater T 2 relaxivity enhanced and nano-heating capabilities due to increased surface area. Increasing the gold nano-shell thickness resulted in a decreased efficiency as a nano-heater along with a decrease in T 2 relaxivity. These results highlight the importance of identifying the key traits required when fabricating HNPs in order to tailor them to specific applications.

Extrinsic morphology of graphene

International Nuclear Information System (INIS)

Li, Teng

2011-01-01

Graphene is intrinsically non-flat and corrugates randomly. Since the corrugating physics of atomically thin graphene is strongly tied to its electronics properties, randomly corrugating morphology of graphene poses a significant challenge to its application in nanoelectronic devices for which precise (digital) control is the key. Recent studies revealed that the morphology of substrate-supported graphene is regulated by the graphene–substrate interaction, thus is distinct from the random intrinsic morphology of freestanding graphene. The regulated extrinsic morphology of graphene sheds light on new pathways to fine tune the properties of graphene. To guide further research to explore these fertile opportunities, this paper reviews recent progress on modeling and experimental studies of the extrinsic morphology of graphene under a wide range of external regulation, including two-dimensional and one-dimensional substrate surface features and one-dimensional and zero-dimensional nanoscale scaffolds (e.g. nanowires and nanoparticles)

Synthesis and characterization of iron based nanoparticles for novel applications

Science.gov (United States)

Khurshid, Hafsa

The work in this thesis has been focused on the fabrication and characterization of iron based nanoparticles with controlled size and morphology with the aim: (i) to investigate their properties for potential applications in MICR toners and biomedical field and (ii) to study finite size effects on the magnetic properties of the nanoparticles. For the biomedical applications, core/shell structured iron/iron-oxide and hollow shell nanoparticles were synthesized by thermal decomposition of iron organometallic compounds [Fe(CO)5] at high temperature. Core/shell structured iron/iron-oxide nanoparticles have been prepared in the presence of oleic acid and oleylamine. Particle size and composition was controlled by varying the reaction parameters during synthesis. The as-made particles are hydrophobic and not dispersible in water. Water dispersibility was achieved by ligand exchange a with double hydrophilic diblock copolymer. Relaxometery measurements of the transverse relaxation time T2 of the nanoparticles solution at 3 Tesla confirm that the core/shell nanoparticles are an excellent MRI contrast agent using T2 weighted imaging sequences. In comparison to conventionally used iron oxide nanoparticles, iron/iron-oxide core/shell nanoparticles offer four times stronger T2 shortening effect at comparable core size due to their higher magnetization. The magnetic properties were studied as a function of particle size, composition and morphology. Hollow nanostructures are composed of randomly oriented grains arranged together to make a shell layer and make an interesting class of materials. The hollow morphology can be used as an extra degree of freedom to control the magnetic properties. Owing to their hollow morphology, they can be used for the targeted drug delivery applications by filling the drug inside their cavity. For the magnetic toners applications, particles were synthesized by chemically reducing iron salt using sodium borohydride and then coated with polyethylene

Metagenomic analysis of microbial communities yields insight into impacts of nanoparticle design

Science.gov (United States)

Metch, Jacob W.; Burrows, Nathan D.; Murphy, Catherine J.; Pruden, Amy; Vikesland, Peter J.

2018-01-01

Next-generation DNA sequencing and metagenomic analysis provide powerful tools for the environmentally friendly design of nanoparticles. Herein we demonstrate this approach using a model community of environmental microbes (that is, wastewater-activated sludge) dosed with gold nanoparticles of varying surface coatings and morphologies. Metagenomic analysis was highly sensitive in detecting the microbial community response to gold nanospheres and nanorods with either cetyltrimethylammonium bromide or polyacrylic acid surface coatings. We observed that the gold-nanoparticle morphology imposes a stronger force in shaping the microbial community structure than does the surface coating. Trends were consistent in terms of the compositions of both taxonomic and functional genes, which include antibiotic resistance genes, metal resistance genes and gene-transfer elements associated with cell stress that are relevant to public health. Given that nanoparticle morphology remained constant, the potential influence of gold dissolution was minimal. Surface coating governed the nanoparticle partitioning between the bioparticulate and aqueous phases.

Morphologically controlled ZnO nanostructures as electron transport materials in polymer-based organic solar cells

International Nuclear Information System (INIS)

Choi, Kyu-Chae; Lee, Eun-Jin; Baek, Youn-Kyoung; Lim, Dong-Chan; Kang, Yong-Cheol; Kim, Yang-Do; Kim, Ki Hyun; Kim, Jae Pil; Kim, Young-Kuk

2015-01-01

Highlights: • Enhanced efficiency of solar cells using ZnO nanocrystals for charge transport. • Morphology of the charge transport layer is controlled. • Mixture of nanoparticles and nanorods are advantageous for cell efficiency. - ABSTRACT: The morphology of ZnO electron transport layers based on ZnO nanoparticles were modified with incorporation of ZnO nanorods via their co-deposition from mixed colloidal solution of nanoparticles and nanorods. In particular, the short circuit current density and the fill factor of the constructed photovoltaic device were simultaneously improved by applying mixture of ZnO nanoparticles and nanorods. As a result, a large improvement of power conversion efficiency up to 9% for the inverted organic solar cells having a blend of low band gap polymers and fullerene derivative as an active layer was demonstrated with the morphologically controlled ZnO electron transport layer.

Periodic Mesoporous Organosilica Nanoparticles with Controlled Morphologies and High Drug/Dye Loadings for Multicargo Delivery in Cancer Cells

KAUST Repository

Croissant, Jonas G.

2016-06-01

Despite the worldwide interest generated by periodic mesoporous organosilica (PMO) bulk materials, the design of PMO nanomaterials with controlled morphology remains largely unexplored and their properties unknown. In this work, we describe the first study of PMO nanoparticles (NPs) based on meta-phenylene bridges, and we conducted a comparative structure–property relationship investigation with para-phenylene-bridged PMO NPs. Our findings indicate that the change of the isomer drastically affects the structure, morphology, size, porosity and thermal stability of PMO materials. We observed a much higher porosity and thermal stability of the para-based PMO which was likely due to a higher molecular periodicity. Additionally, the para isomer could generate multipodal NPs at very low stirring speed and upon this discovery we designed a phenylene–ethylene bridged PMO with a controlled Janus morphology. Unprecedentedly high payloads could be obtained from 40 to 110 wt % regardless of the organic bridge of PMOs. Finally, we demonstrate for the first time the co-delivery of two cargos by PMO NPs. Importantly, the cargo stability in PMOs did not require the capping of the pores, unlike pure silica, and the delivery could be autonomously triggered in cancer cells by acidic pH with nearly 70 % cell killing. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Morphological and electrical properties of self-assembled iron silicide nanoparticles on Si(0 0 1) and Si(1 1 1) substrates

International Nuclear Information System (INIS)

Molnár, G.; Dózsa, L.; Erdélyi, R.; Vértesy, Z.; Osváth, Z.

2015-01-01

Highlights: • Epitaxial iron silicide nanostructures were grown on Si(1 1 1) and Si(0 0 1) substrates. • The size and shape of the particles are the function of the thickness and annealing. • The local current–voltage characteristics were measured by conductive AFM. • The different size and shape nanoparticles show similar I–V characteristics. • The tip current is dominated in few nm size sites, visible in the AFM phase image. - Abstract: Epitaxial iron silicide nanostructures are grown by solid phase epitaxy on Si(0 0 1) and Si(1 1 1), and by reactive deposition epitaxy on Si(0 0 1) substrates. The formation process is monitored by reflection high-energy electron diffraction. The morphology, size, and electrical properties of the nanoparticles are investigated by scanning electron microscopy, by electrically active scanning probe microscopy, and by confocal Raman spectroscopy. The results show that the shape, size, orientation, and density of the nanoobjects can be tuned by self-assembly, controlled by the lattice misfit between the substrates and iron silicides. The size distribution and shape of the grown nanoparticles depend on the substrate orientation, on the initial thickness of the evaporated iron, on the temperature and time of the annealing, and on the preparation method. The so-called Ostwald ripening phenomena, which state that the bigger objects develop at the expense of smaller ones, controls the density of the nanoparticles. Raman spectra show the bigger objects do not contain β-FeSi 2 phase. The different shape nanoparticles exhibit small, about 100 mV barrier compared to the surrounding silicon. The local leakage current of the samples measured by conductive AFM using a Pt coated Si tip is localized in a few nanometers size sites, and the sites which we assume are very small silicide nanoparticles or point defects.

The Effect of Solvents, Acetone, Water, and Ethanol, on the Morphological and Optical Properties of ZnO Nanoparticles Prepared by Microwave

Directory of Open Access Journals (Sweden)

Phindile B. Khoza

2012-01-01

Full Text Available HDA-capped ZnO nanoparticles were prepared by solvothermal method using solvents of different polarities. A number of parameters were kept constant such as temperature, pressure, time, and pH while solvents were varied, that is, water, ethanol, and acetone. The TEM was used for the structural properties and morphologies such as spheres, mixture of rods, and spheres and stars were obtained in ethanol, acetone, and water, respectively, in a given reaction time of 15 minutes. Both ethanol and acetone gave rods with high aspect ratio primarily because of the lengths of the rods. Water and ethanol have the hydroxyl groups which interact with nanoparticles from nucleation, growth, and termination giving rise to nonspherical shapes. The hydroxyl group promotes growth in a nonuniform way resulting in stars and rods. The optical features were typical of ZnO nanoparticles with excitonic peaks in the range 368 to 374 nm from their absorption spectra. The XRD patterns of the particles gave the most stable form of ZnO which is the hexagonal phase, with high degree of crystallinity and with the 101 plane predominant in all solvents.

Sol–gel synthesis of nanostructured indium tin oxide with controlled morphology and porosity

Energy Technology Data Exchange (ETDEWEB)

Kőrösi, László, E-mail: ltkorosi@gmail.com [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632 Pécs (Hungary); Scarpellini, Alice [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Petrik, Péter [Institute for Technical Physics and Materials Science, Konkoly-Thege út 29-33, H-1121 Budapest (Hungary); Papp, Szilvia [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632 Pécs (Hungary); Dékány, Imre [MTA-SZTE Supramolecular and Nanostructured Materials Research Group, University of Szeged, Dóm tér 8, H-6720 Szeged (Hungary)

2014-11-30

Graphical abstract: - Highlights: • Nanocrystalline ITO thin films and powders were prepared by a sol–gel method. • The nature of the compounds used for hydrolysis plays a key role in the morphology. • Hydrolysis of In{sup 3+}/Sn{sup 4+} with EA led to a rod-like morphology. • Monodisperse spherical ITO nanoparticles were obtained on the use of AC. • ITO{sub E}A was highly porous, while ITO{sub A}C contained densely packed nanocrystals. - Abstract: Nanostructured indium tin oxide (ITO) powders and thin films differing in morphology and porosity were prepared by a sol–gel method. In{sup 3+} and Sn{sup 4+} were hydrolyzed in aqueous medium through the use of ethanolamine (EA) or sodium acetate (AC). X-ray diffraction measurements demonstrated that both EA and AC furnished indium tin hydroxide, which became nanocrystalline after aging for one day. The indium tin hydroxide samples calcined at 550 °C afforded ITO with a cubic crystal structure, but the morphology differed significantly, depending on the agent used for hydrolysis. Electron microscopy revealed the formation of round monodisperse nanoparticles when AC was used, whereas the application of EA led to rod-like ITO nanoparticles. Both types of nanoparticles were suitable for the preparation of transparent and conductive ITO thin films. The influence of the morphology and porosity on the optical properties is discussed.

Achieving 3-D Nanoparticle Assembly in Nanocomposite Thin Films via Kinetic Control

Energy Technology Data Exchange (ETDEWEB)

Huang, Jingyu; Xiao, Yihan; Xu, Ting [UCB

2017-02-20

Nanocomposite thin films containing well-ordered nanoparticle (NP) assemblies are ideal candidates for the fabrication of metamaterials. Achieving 3-D assembly of NPs in nanocomposite thin films is thermodynamically challenging as the particle size gets similar to that of a single polymer chain. The entropic penalties of polymeric matrix upon NP incorporation leads to NP aggregation on the film surface or within the defects in the film. Controlling the kinetic pathways of assembly process provides an alternative path forward by arresting the system in nonequilibrium states. Here, we report the thin film 3-D hierarchical assembly of 20 nm NPs in supramolecules with a 30 nm periodicity. By mediating the NP diffusion kinetics in the supramolecular matrix, surface aggregation of NPs was suppressed and NPs coassemble with supramolecules to form new 3-D morphologies in thin films. The present studies opened a viable route to achieve designer functional composite thin films via kinetic control.

Hybrid, silica-coated, Janus-like plasmonic-magnetic nanoparticles

OpenAIRE

Sotiriou, Georgios A.; Hirt, Ann M.; Lozach, Pierre-Yves; Teleki, Alexandra; Krumeich, Frank; Pratsinis, Sotiris E.

2011-01-01

Hybrid plasmonic-magnetic nanoparticles possess properties that are attractive in bioimaging, targeted drug delivery, in vivo diagnosis and therapy. The stability and toxicity, however, of such nanoparticles challenge their safe use today. Here, biocompatible, SiO2-coated, Janus-like Ag/Fe2O3 nanoparticles are prepared by one-step, scalable flame aerosol technology. A nanothin SiO2 shell around these multifunctional nanoparticles leaves intact their morphology, magnetic and plasmonic properti...

Template preparation of twisted nanoparticles of mesoporous silica

Institute of Scientific and Technical Information of China (English)

Kui Niu; Zhongbin Ni; Chengwu Fu; Tatsuo Kaneko; Mingqing Chen

2011-01-01

Optical isomers of N-lauroyl-L-(or-D-) alanine sodium salt {C12-L-(or-D-)AlaS} surfactants were used for the preparation of mesoporous silica nanoparticles with a twisted hexagonal rod-like morphology. Thermogravimetric analysis (TGA) was used to determine the temperature for template removal. Circular dichroism (CD) spectra of the surfactant solution with various compositions illustrated the formation and supramolecular assembly of protein-like molecular architecture leading to formation of twisted nanoparticles. Scanning electron microscopy (SEM),high-resolution transmission electron microscopy (HRTEM)and X-ray powder diffraction (XRD) patterns of these as-synthesized mesoporous silica confirmed that the twisted morphology of these nanoparticles was closely related to the supramolecular-assembled complex of amino acid surfactants.

Creating Hierarchical Pores by Controlled Linker Thermolysis in Multivariate Metal-Organic Frameworks

KAUST Repository

Feng, Liang

2018-01-18

Sufficient pore size, appropriate stability and hierarchical porosity are three prerequisites for open frameworks designed for drug delivery, enzyme immobilization and catalysis involving large molecules. Herein, we report a powerful and general strate-gy, linker thermolysis, to construct ultra-stable hierarchically porous metal−organic frameworks (HP-MOFs) with tunable pore size distribution. Linker instability, usually an undesirable trait of MOFs, was exploited to create mesopores by generating crystal defects throughout a microporous MOF crystal via thermolysis. The crystallinity and stability of HP-MOFs remain after thermolabile linkers are selectively removed from multivariate metal-organic frameworks (MTV-MOFs) through a decarboxyla-tion process. A domain-based linker spatial distribution was found to be critical for creating hierarchical pores inside MTV-MOFs. Furthermore, linker thermolysis promotes the formation of ultra-small metal oxide (MO) nanoparticles immobilized in an open framework that exhibits high catalytic activity for Lewis acid catalyzed reactions. Most importantly, this work pro-vides fresh insights into the connection between linker apportionment and vacancy distribution, which may shed light on prob-ing the disordered linker apportionment in multivariate systems, a long-standing challenge in the study of MTV-MOFs.

Effect of the sheet thickness of hierarchical SnO_2 on the gas sensing performance

International Nuclear Information System (INIS)

Zhang, Wenlong; Zeng, Wen; BinMiao; Wang, Zhongchang

2015-01-01

Graphical abstract: - Highlights: • A unique flower-like SnO_2 hierarchical architecture assembled with nanosheets were successfully synthesized. • The thickness of the unique hierarchical nanoflowers was precisely controlled. • The nanoflowers composed of thinner nanosheets show a significantly enhanced gas sensing properties. • A possible growth mechanism for the unique hierarchical SnO_2 nanoflower assembled with nanosheets of different thickness is proposed. - Abstract: A unique hierarchical SnO_2 nanoflower was successfully synthesized via a facile one-step hydrothermal method. The nanoflower was analyzed in detail using X ray diffraction, field-emission electron microscope and transmission electron microscope. It was found that the nanoflowers are all assembled from nanosheets. The nanosheet thickness could be precisely controlled by tuning the dosage of NaOH. Gas sensing tests demonstrated that the thickness of the sheet significantly affects the gas sensing performance. The improved gas sensing properties are attributed to the thinned petals as well as their pores and defects. These results show that the thickness and morphology of hierarchical nanostructures affect the functionality of gas sensors.

Morphology-controlled synthesis of MoS2 nanostructures with different lithium storage properties

International Nuclear Information System (INIS)

Wang, Xiwen; Zhang, Zhian; Chen, Yaqiong; Qu, Yaohui; Lai, Yanqing; Li, Jie

2014-01-01

Highlights: • MoS 2 nanospheres, nanoribbons and nanoparticles were prepared by hydrothermal method. • The surfactant and temperature control the shape and crystal structure of MoS 2 . • MoS 2 nanospheres exhibit the excellent lithium storage property. - Abstract: A one-step hydrothermal process was employed to prepare a series of MoS 2 nanostructures via simply altering the surfactant as soft template and hydrothermal reaction temperature. Three kinds of MoS 2 nanostructures (three-dimensional (3D) hierarchical nanospheres, one-dimensional (1D) nanoribbons, and large aggregated nanoparticles) were successfully achieved and investigated well by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), and Brunauer–Emmett–Teller analysis (BET). Electrochemical tests reveal that these MoS 2 samples could deliver high initial discharge capacities (higher than 1050.0 mA h g −1 ), but various cycling performances. The hierarchical MoS 2 nanospheres assembled by sheet-like subunits show the highest specific capacity of 1355.1 mA h g −1 , and 66.8% of which can be retained after 50 cycles. The good lithium storage property of hierarchical MoS 2 nanospheres can be attributed to the higher electrolyte/MoS 2 contact area and stable 3D layered structure

The hierarchical nature of the spin alignment of dark matter haloes in filaments

Science.gov (United States)

Aragon-Calvo, M. A.; Yang, Lin Forrest

2014-05-01

Dark matter haloes in cosmological filaments and walls have (in average) their spin vector aligned with their host structure. While haloes in walls are aligned with the plane of the wall independently of their mass, haloes in filaments present a mass-dependent two-regime orientation. Here, we show that the transition mass determining the change in the alignment regime (from parallel to perpendicular) depends on the hierarchical level in which the halo is located, reflecting the hierarchical nature of the Cosmic Web. By explicitly exposing the hierarchical structure of the Cosmic Web, we are able to identify the contributions of different components of the filament network to the alignment signal. We propose a unifying picture of angular momentum acquisition that is based on the results presented here and previous results found by other authors. In order to do a hierarchical characterization of the Cosmic Web, we introduce a new implementation of the multiscale morphology filter, the MMF-2, that significantly improves the identification of structures and explicitly describes their hierarchy. L36

Hierarchical ordering with partial pairwise hierarchical relationships on the macaque brain data sets.

Directory of Open Access Journals (Sweden)

Woosang Lim

Full Text Available Hierarchical organizations of information processing in the brain networks have been known to exist and widely studied. To find proper hierarchical structures in the macaque brain, the traditional methods need the entire pairwise hierarchical relationships between cortical areas. In this paper, we present a new method that discovers hierarchical structures of macaque brain networks by using partial information of pairwise hierarchical relationships. Our method uses a graph-based manifold learning to exploit inherent relationship, and computes pseudo distances of hierarchical levels for every pair of cortical areas. Then, we compute hierarchy levels of all cortical areas by minimizing the sum of squared hierarchical distance errors with the hierarchical information of few cortical areas. We evaluate our method on the macaque brain data sets whose true hierarchical levels are known as the FV91 model. The experimental results show that hierarchy levels computed by our method are similar to the FV91 model, and its errors are much smaller than the errors of hierarchical clustering approaches.

Investigation of Combination Effect of Magnesium Oxide and Iron Oxide Nanoparticles on the Growth And Morphology of the Bacteria Staphylococcus Aureus and Escherichia Coli in Juice

Directory of Open Access Journals (Sweden)

mahdi torabi zarchi

2017-02-01

Full Text Available Introduction: Nanoparticles (NPs are one of the antibacterial substances, among them nanoparticles type MgO and Fe2O3 are less toxic to mammalian cells. So, the aim of this study was investigation of combination effects of iron oxide and magnesium oxide nanoparticles on the growth of Staphylococcus aureus and Escherichia coli (E.coli to achieve the optimum combination of nanoparticles inhibit the growth of Staphylococcus aureus and Escherichia coli in food (juice. Methods: In this experimental research, the effect of MgO and Fe2O3 Nanoparticles compound on Staphylococcus aureus and Escherichia coli bacteria in liquid environment was investigated, and then their effect was investigated separately in juices of carrot, pomegranate and apple via colony count approach. Also, scanning electron microscopy was used to characterize the morphological changes of Staphylococcus aureus and Escherichia coli after antimicrobial treatments. The results of the research were analyzed using one way ANNOVA. Results: The results of the research indicated that in liquid medium, these nanoparticles lead to reduce the growth of both bacteria. compound of 1.5Mg+0.5Fe2O3 was introduced as the most appropriate antibacterial compounds; Staphylococcus aureus sensitivity to Escherichia coli was higher against nanoparticles. The findings of research about the juices revealed that the combined effect of nanoparticles reduced the growth of both bacteria. the combined effect of Fe2o3 and MgO nanoparticles treatments distorted and damaged the cell membrane, resulting in a leakage of intracellular contents and eventually the death of bacterial cells. Conclusion: Nanoparticles in the allowed concentrations have significant effect on Staphylococcus aureus and Escherichia coli bacteria.

Engineering tailored nanoparticles with microbes: quo vadis?

Science.gov (United States)

Prasad, Ram; Pandey, Rishikesh; Barman, Ishan

2016-01-01

In the quest for less toxic and cleaner methods of nanomaterials production, recent developments in the biosynthesis of nanoparticles have underscored the important role of microorganisms. Their intrinsic ability to withstand variable extremes of temperature, pressure, and pH coupled with the minimal downstream processing requirements provide an attractive route for diverse applications. Yet, controlling the dispersity and facile tuning of the morphology of the nanoparticles of desired chemical compositions remains an ongoing challenge. In this Focus Review, we critically review the advances in nanoparticle synthesis using microbes, ranging from bacteria and fungi to viruses, and discuss new insights into the cellular mechanisms of such formation that may, in the near future, allow complete control over particle morphology and functionalization. In addition to serving as paradigms for cost-effective, biocompatible, and eco-friendly synthesis, microbes hold the promise for a unique template for synthesis of tailored nanoparticles targeted at therapeutic and diagnostic platform technologies. © 2015 Wiley Periodicals, Inc.

Optical and surface morphological properties of triethylamine passivated lead sulphide nanoparticles

International Nuclear Information System (INIS)

Navaneethan, M.; Nisha, K.D.; Ponnusamy, S.; Muthamizhchelvan, C.

2009-01-01

The triethylamine capped lead sulphide (PbS) nanoparticles were successfully synthesized by simple wet chemical method. The synthesized product has been characterized by powder X-ray diffraction (XRD), UV-vis spectrophotometry, FTIR spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM) and photoluminescence studies. The size of the PbS nanoparticles was determined from AFM, TEM, XRD and from these studies it is found that the size of the particles of the order of 10-15 nm. Significant 'blue shift' from bulk material was observed on the PbS nanoparticles using UV-vis and photoluminescence spectrum.

Nanoparticles for cells proliferation enhancement

International Nuclear Information System (INIS)

Popa, V.; Braniste, F.; Tiginyanu, I.M.; Lisii, C.; Nacu, V.

2013-01-01

The potential of semiconductor nanoparticles as stimulator for avian mesenchyme stem cells proliferation enhancement is demonstrated. The effect is related to nanoparticles polarization due to external ultrasound field resulting in local electrical stimulation. Our preliminary results demonstrates that the number of cells have been increased by 23 % ±2%) in cell cultures under the action of external ultrasound stimulation. Morphological analysis and viability shows no differences between the control group and the group studied. These results suggest the possibility for tissue regeneration enhancement by remote stimulation of implanted semiconductor nanoparticles. (authors)

A Hierarchically Micro-Meso-Macroporous Zeolite CaA for Methanol Conversion to Dimethyl Ether

Directory of Open Access Journals (Sweden)

Yan Wang

2016-11-01

Full Text Available A hierarchical zeolite CaA with microporous, mesoporous and macroporous structure was hydrothermally synthesized by a ”Bond-Blocking” method using organo-functionalized mesoporous silica (MS as a silica source. The characterization by XRD, SEM/TEM and N2 adsorption/desorption techniques showed that the prepared material had well-crystalline zeolite Linde Type A (LTA topological structure, microspherical particle morphologies, and hierarchically intracrystalline micro-meso-macropores structure. With the Bond-Blocking principle, the external surface area and macro-mesoporosity of the hierarchical zeolite CaA can be adjusted by varying the organo-functionalized degree of the mesoporous silica surface. Similarly, the distribution of the micro-meso-macroporous structure in the zeolite CaA can be controlled purposely. Compared with the conventional microporous zeolite CaA, the hierarchical zeolite CaA as a catalyst in the conversion of methanol to dimethyl ether (DME, exhibited complete DME selectivity and stable catalytic activity with high methanol conversion. The catalytic performances of the hierarchical zeolite CaA results clearly from the micro-meso-macroporous structure, improving diffusion properties, favoring the access to the active surface and avoiding secondary reactions (no hydrocarbon products were detected after 3 h of reaction.

Mechanistic aspects of biogenic synthesis of CdS nanoparticles using Bacillus licheniformis

Science.gov (United States)

Tripathi, R. M.; Singh Bhadwal, Akhshay; Singh, Priti; Shrivastav, Archana; Singh, M. P.; Shrivastav, B. R.

2014-06-01

A novel eco-friendly effort has been made for the synthesis of cadmium sulfide (CdS) nanoparticles using bacterial biomass. Although some articles have been reported on CdS nanoparticles synthesis by bacteria, here we have synthesized CdS nanoparticles using non-pathogenic bacteria Bacillus licheniformis MTCC 9555. UV-Vis spectroscopy was carried out to confirm the formation of CdS nanoparticles; the peak occurring at 368 nm gives the indication of synthesis of CdS nanoparticles. The size and morphology of the synthesized CdS nanoparticles were analyzed by transmission electron microscopy (TEM) and the nanoparticles are found to have a narrow size of 5.1 ± 0.5 nm with spherical morphology. Further, the nanoparticles were examined by energy dispersive x-ray (EDX) spectroscopy to identify the presence of elements and confirmed the existence of Cd and S in single nanoparticles. X-ray diffraction (XRD) analysis exhibited 2θ values corresponding to CdS nanocrystals. Fourier transform infrared spectroscopy (FTIR) provides the evidence for the presence of proteins as possible biomolecules responsible for the stabilization of the synthesized CdS nanoparticles.

Directed Hierarchical Patterning of Polycarbonate Bisphenol A Glass Surface along Predictable Sites

Directory of Open Access Journals (Sweden)

Mazen Khaled

2015-01-01

Full Text Available This paper reports a new approach in designing textured and hierarchical surfaces on polycarbonate bisphenol A type glass to improve hydrophobicity and dust repellent application for solar panels. Solvent- and vapor-induced crystallization of thermoplastic glass polycarbonate bisphenol A (PC is carried out to create hierarchically structured surfaces. In this approach dichloromethane (DCM and acetone are used in sequence. Samples are initially immersed in DCM liquid to generate nanopores, followed by exposing to acetone vapor resulting in the generation of hierarchical structure along the interporous sites. The effects of exposure time on the size, density, and distance of the generated spherules and gaps are studied and correlated with the optical transmittance and contact angle measurements at the surface. At optimized exposure time a contact angle of 98° was achieved with 80% optical transmittance. To further increase the hydrophobicity while maintaining optical properties, the hierarchical surfaces were coated with a transparent composite of tetraethyl orthosilicate as precursor and hexamethyldisilazane as silylation agent resulting in an average contact angle of 135.8° and transmittance of around 70%. FTIR and AFM characterization techniques are employed to study the composition and morphology of the generated surfaces.

Hierarchical carbon nanopetal/polypyrrole nanocomposite electrodes with brush-like architecture for supercapacitors.

Science.gov (United States)

Cherusseri, Jayesh; Kar, Kamal K

2016-03-28

Hierarchical 3D nanocomposite electrodes with tube brush-like morphology are synthesized by electrochemically depositing polypyrrole (PPY) on carbon nanopetal (CNP) coated carbon fibers (CFs). Initially CNPs are synthesized on CF substrate by chemical vapour deposition. The CNPs synthesized on CF (CNPCF) are further used as an electrically conducting large surface area bearing template for the electropolymerization of PPY in order to fabricate CNPCF-PPY nanocomposite electrodes for supercapacitors (SCs). The CF in CNPCF-PPY nanocomposite functions as (i) a mechanical support for the CNPs, (ii) a current collector for the SC cell and also (iii) to prevent the agglomeration of CNPs within the CNPCF-PPY nanocomposite. Transmission electron microscopy and scanning electron microscopy are used to examine the surface morphology of CNPCF-PPY nanocomposites. The chemical structure of the nanocomposites is analysed by Fourier transform infrared spectroscopy. X-Ray photoelectron spectroscopy has been used to understand the chemical bonding states of the hierarchical CNPCF-PPY nanocomposites. The electrochemical properties of symmetric type CNPCF-PPY SC cells are examined by electrochemical impedance spectroscopy, cyclic voltammetry and galvanostatic charge-discharge measurements. The hierarchical CNPCF-PPY SC exhibits a maximum gravimetric capacitance of 280.4 F g(-1) and an area specific capacitance of 210.3 mF cm(-2) at a current density of 0.42 mA cm(-2). The CNPCF-PPY SC cell exhibits good cycling stability of more than 5000 cycles. The present study proclaims the development of a novel lightweight SC with high-performance.

Synthesis of CuO-NiO core-shell nanoparticles by homogeneous precipitation method

International Nuclear Information System (INIS)

Bayal, Nisha; Jeevanandam, P.

2012-01-01

Highlights: ► CuO-NiO core-shell nanoparticles have been synthesized using a simple homogeneous precipitation method for the first time. ► Mechanism of the formation of core-shell nanoparticles has been investigated. ► The synthesis route may be extended for the synthesis of other mixed metal oxide core-shell nanoparticles. - Abstract: Core-shell CuO–NiO mixed metal oxide nanoparticles in which CuO is the core and NiO is the shell have been successfully synthesized using homogeneous precipitation method. This is a simple synthetic method which produces first a layered double hydroxide precursor with core-shell morphology which on calcination at 350 °C yields the mixed metal oxide nanoparticles with the retention of core-shell morphology. The CuO–NiO mixed metal oxide precursor and the core-shell nanoparticles were characterized by powder X-ray diffraction, FT-IR spectroscopy, thermal gravimetric analysis, elemental analysis, scanning electron microscopy, transmission electron microscopy, and diffuse reflectance spectroscopy. The chemical reactivity of the core-shell nanoparticles was tested using catalytic reduction of 4-nitrophenol with NaBH 4 . The possible growth mechanism of the particles with core-shell morphology has also been investigated.

The Cytotoxicity, Characteristics, and Optimization of Insulin-loaded Nanoparticles

Directory of Open Access Journals (Sweden)

Yasemin Budama-Kilinc

2017-04-01

Full Text Available Controlled release systems for insulin are frequent subjects of research, because it is rapidly degraded by proteolytic enzymes in the gastrointestinal tract and minimally absorbed after oral administration. Controlled release systems also provide significant contribution to its stability.  Different techniques are used for the preparation of drug-loaded nanoparticles, and many novel techniques are being developed. The size and morphology of insulin-loaded nanoparticles may vary according to performed techniques, even if the same polymer is used. The aim of this study was to demonstrate the cytotoxicity of insulin loaded nanoparticles and the effect of various synthesis parameters on the particle size, polydispersity index (PdI, loading efficiency, and particle morphology. In the experiments, poly(lactic-co-glycolic acid (PLGA and insulin-loaded PLGA nanoparticles were prepared using the double emulsion (w/o/w method. The characterization of the nanoparticles were performed with a UV spectrometer, the Zeta-sizer system, FTIR spectroscopy, and a scanning probe microscope. Cell toxicity of different concentrations was assayed with MTT methods on L929 fibroblast cells. The optimum size of the insulin-loaded PLGA nanoparticle was obtained with a 96.5% encapsulation efficiency, a 224.5 nm average particle size, and a 0.063 polydispersity index. This study obtained and characterized spherical morphology, determined that the nanoparticles have very low toxicity, and showed the effect of different parameters on particle size and polydispersity. DOI: http://dx.doi.org/10.17807/orbital.v9i1.934 

Zein/caseinate/pectin complex nanoparticles: Formation and characterization.

Science.gov (United States)

Chang, Chao; Wang, Taoran; Hu, Qiaobin; Luo, Yangchao

2017-11-01

In this study, pectin was used as coating material to form zein/caseinate/pectin complex nanoparticles through pH adjustment and heating treatment for potential oral delivery applications. The preparation conditions were studied by applying heating treatment at different pHs, either the isoelectric point of zein (pH 6.2) or caseinate (pH 4.6), or consecutively at both pHs. The particulate characteristics, including particle size, polydispersity index, and zeta potential were monitored for complex nanoparticles formed under different preparation conditions. The complex nanoparticles generally exhibited particle size smaller than 200nm with narrow distribution, spherical shape, and strong negative charge. Fourier transform infrared and fluorescence spectroscopy revealed that hydrophobic interactions and hydrogen bonds were involved in the formation of complex nanoparticles, in addition to electrostatic interactions. Fresh colloidal dispersion and freeze-dried powders varied in their morphology, depending on their preparation conditions. Our results suggested that heating pH and sequence significantly affected the morphology of complex nanoparticles, and pectin coating exerted stabilization effect under simulated gastrointestinal conditions. The present study provides insight into the formation of protein/polysaccharide complex nanoparticles under different preparation conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Polypropylene Nanocomposites Obtained by In Situ Polymerization Using Metallocene Catalyst: Influence of the Nanoparticles on the Final Polymer Morphology

Directory of Open Access Journals (Sweden)

Paula Zapata

2012-01-01

Full Text Available Polypropylene nanocomposites containing silica nanospheres based on the sol-gel methods were produced via in situ polymerization using a rac-Et(Ind2ZrCl2/methylaluminoxane (MAO system. Two different routes were used depending on the interaction between the silica nanoparticles with the catalytic system. In route 1 the nanoparticles were added together with the catalytic system (rac-Et(Ind2ZrCl2/(MAO directly into the reactor, and in route 2 the metallocene rac-Et(Ind2ZrCl2 was supported on silica nanospheres pretreated with (MAO. SEM images show that when the nanospheres were added by both routes, they were replicated in the final polymer particle morphology; this phenomenon was more pronounced for PP obtained by route 2. The polypropylene (PP nanocomposites obtained by both routes had a slightly higher percent crystallinities and crystallinity temperatures than pure PP. Transmission electron microscopy (TEM images show that the nanospheres were well dispersed into the polypropylene matrix, particularly in the nanocomposites obtained by the support system (route 2.

Magnetic behavior of iron oxide nanoparticle-biomolecule assembly

International Nuclear Information System (INIS)

Kim, Taegyun; Reis, Lynn; Rajan, Krishna; Shima, Mutsuhiro

2005-01-01

Iron oxide nanoparticles of 8-20 nm in size were investigated as an assembly with biomolecules synthesized in an aqueous solution. The magnetic behavior of the biomolecule-nanoparticles assembly depends sensitively on the morphology and hence the distribution of the nanoparticles, where the dipole coupling between the nanoparticles governs the overall magnetic behavior. In assemblies of iron oxide nanoparticles with trypsin, we observe a formation of unusual self-alignment of nanoparticles within trypsin molecules. In such an assembly structure, the magnetic particles tend to exhibit a lower spin-glass transition temperature than as-synthesized bare iron oxide nanoparticles probably due to reduced interparticle couplings within the molecular matrix. The observed self-alignment of nanoparticles in biomolecules may be a useful approach for directed nanoparticles assembly

Stabilized amorphous glibenclamide nanoparticles by high-gravity technique

International Nuclear Information System (INIS)

Yu Lei; Li Caixia; Le Yuan; Chen Jianfeng; Zou Haikui

2011-01-01

Highlights: · Amorphous glibenclamide nanoparticles of 220 nm are obtained using the high-gravity technique. · The dissolution rate of these nanoparticles achieves 85% in 5 min, while those of the raw glibenclamide and the commercial glibenclamide tablet only reach 35% and 55% respectively during the same period. · The morphology, particle size, crystalline form and dissolution rate of these nanoparticles almost remain constant after keeping more than 70 days. - Abstract: The stable amorphous glibenclamide nanoparticles was obtained via anti-solvent precipitation using the high-gravity technique in this study. The effects of operating variables on the particle size were investigated. The properties of glibenclamide nanoparticles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) and dissolution test. The prepared glibenclamide nanoparticles had a mean size of 220 nm within a narrow distribution. The dissolution rate of glibenclamide nanoparticles was obviously faster than that of the raw glibenclamide or the commercial glibenclamide tablet. It achieved 85% in 5 min, while those of the raw glibenclamide and the commercial glibenclamide tablet achieved 35% and 55% respectively during the same period. The physical stability of the nanoparticles was tested after storing for more than 70 days at room conditions. Their morphology, particle size, crystalline form and dissolution rate almost remained constant during storage.

Stability of Porous Platinum Nanoparticles: Combined In Situ TEM and Theoretical Study

DEFF Research Database (Denmark)

Chang, Shery L. Y.; Barnard, Amanda S.; Dwyer, Christian

2012-01-01

Porous platinum nanoparticles provide a route for the development of catalysts that use less platinum without sacrificing catalytic performance. Here, we examine porous platinum nanoparticles using a combination of in situ transmission electron microscopy and calculations based on a first-principles......-parametrized thermodynamic model. Our experimental observations show that the initially irregular morphologies of the as-sythesized porous nanoparticles undergo changes at high temperatures to morphologies having faceted external surfaces with voids present in the interior of the particles. The increasing size of stable...

Hierarchically porous MnO2 microspheres doped with homogeneously distributed Fe3O4 nanoparticles for supercapacitors.

Science.gov (United States)

Zhu, Jian; Tang, Shaochun; Xie, Hao; Dai, Yuming; Meng, Xiangkang

2014-10-22

Hierarchically porous yet densely packed MnO2 microspheres doped with Fe3O4 nanoparticles are synthesized via a one-step and low-cost ultrasound assisted method. The scalable synthesis is based on Fe(2+) and ultrasound assisted nucleation and growth at a constant temperature in a range of 25-70 °C. Single-crystalline Fe3O4 particles of 3-5 nm in diameter are homogeneously distributed throughout the spheres and none are on the surface. A systematic optimization of reaction parameters results in isolated, porous, and uniform Fe3O4-MnO2 composite spheres. The spheres' average diameter is dependent on the temperature, and thus is controllable in a range of 0.7-1.28 μm. The involved growth mechanism is discussed. The specific capacitance is optimized at an Fe/Mn atomic ratio of r = 0.075 to be 448 F/g at a scan rate of 5 mV/s, which is nearly 1.5 times that of the extremely high reported value for MnO2 nanostructures (309 F/g). Especially, such a structure allows significantly improved stability at high charging rates. The composite has a capacitance of 367.4 F/g at a high scan rate of 100 mV/s, which is 82% of that at 5 mV/s. Also, it has an excellent cycling performance with a capacitance retention of 76% after 5000 charge/discharge cycles at 5 A/g.

Characterization of hematite nanoparticles synthesized via two different pathways

Science.gov (United States)

Das, Soumya; Hendry, M. Jim

2014-08-01

Hematite is one of the most common and thermodynamically stable iron oxides found in both natural and anthropogenic systems. Owing to its ubiquity, stability, moderate specific surface area, and ability to sequester metals and metalloids from aquatic systems, it has been the subject of a large number of adsorption studies published during the past few decades. Although preparation techniques are known to affect the surface morphology of hematite nanoparticles, the effects of aging under environmentally relevant conditions have yet to be tested with respect to surface morphology, surface area, and adsorptive capacity. We prepared hematite via two different pathways and aged it under highly alkaline conditions encountered in many mill tailings settings. Crystal habits and morphologies of the hematite nanoparticles were analyzed via scanning electron microscopy and transmission electron microscopy. X-ray diffraction, Raman spectroscopy, and Brunauer-Emmett-Teller surface area analyses were also conducted on the hematite nanoparticles before and after aging. The hematite synthesized via an Fe(III) salt solution (average particle size 37 nm) was morphologically and structurally different from the hematite synthesized via ferrihydrite aging (average particle size 144 nm). Overall, our data demonstrate that the crystallinity of hematite produced via ferrihydrite transformation is susceptible to morphological alterations/modifications. In contrast, the hematite formed via hydrolysis of an Fe(III) salt solution remains very stable in terms of structure, size, and morphology even under extreme experimental conditions.

Template-mediated, Hierarchical Engineering of Ordered Mesoporous Films and Powders

Science.gov (United States)

Tian, Zheng

Hierarchical control over pore size, pore topology, and meso/mictrostructure as well as material morphology (e.g., powders, monoliths, thin films) is crucial for meeting diverse materials needs among applications spanning next generation catalysts, sensors, batteries, sorbents, etc. The overarching goal of this thesis is to establish fundamental mechanistic insight enabling new strategies for realizing such hierarchical textural control for carbon materials that is not currently achievable with sacrificial pore formation by 'one-pot' surfactant-based 'soft'-templating or multi-step inorganic 'hard-templating. While 'hard'-templating is often tacitly discounted based upon its perceived complexity, it offers potential for overcoming key 'soft'-templating challenges, including bolstering pore stability, accommodating a more versatile palette of replica precursors, realizing ordered/spanning porosity in the case of porous thin films, simplifying formation of bi-continuous pore topologies, and inducing microstructure control within porous replica materials. In this thesis, we establish strategies for hard-templating of hierarchically porous and structured carbon powders and tunable thin films by both multi-step hard-templating and a new 'one-pot' template-replica precursor co-assembly process. We first develop a nominal hard-templating technique to successfully prepare three-dimensionally ordered mesoporous (3DOm) and 3DOm-supported microporous carbon thin films by exploiting our ability to synthesize and assemble size-tunable silica nanoparticles into scalable, colloidal crystalline thin film templates of tunable mono- to multi-layer thickness. This robust thin film template accommodates liquid and/or vapor-phase infiltration, polymerization, and pyrolysis of various carbon sources without pore contraction and/or collapse upon template sacrifice. The result is robust, flexible 3DOm or 3DOm-supported ultra-thin microporous films that can be transferred by stamp

Effect of annealing temperature on structural, morphological and electrical properties of nanoparticles TiO{sub 2} thin films by sol-gel method

Energy Technology Data Exchange (ETDEWEB)

Muaz, A. K. M.; Hashim, U., E-mail: uda@unimap.edu.my; Arshad, M. K. Md.; Ruslinda, A. R.; Ayub, R. M.; Gopinath, Subash C. B.; Voon, C. H.; Liu, Wei-Wen; Foo, K. L. [Institute of Nano Electronic Engineering, Univerisiti Malaysia Perlis, 01000 Kangar, Perlis (Malaysia)

2016-07-06

In this paper, the sol-gel method is used to prepare nanoparticles titanium dioxide (TiO{sub 2}) thin films at different annealing temperature. The prepared sol was deposited on the p-SiO{sub 2} substrates by spin coating technique under room temperature. The nanoparticles TiO{sub 2} solution was synthesized using Ti{OCH(CH_3)_2}{sub 4} as a precursor with an methanol solution at a molar ratio 1:10. The prepared TiO{sub 2} sols will further validate through structural, morphological and electrical properties. From the X-ray diffraction (XRD) analysis, as-deposited films was found to be amorphous in nature and tend to transform into tetragonal anatase and rutile phase as the films annealed at 573 and 773 K, respectively. The diversification of the surface roughness was characterized by atomic force microscopy (AFM) indicated the roughness and thickness very dependent on the annealing temperature. The two-point probe electrical resistance and conductance of nanoparticles TiO{sub 2} thin films were determined by the DC current-voltage (IV) analysis. From the I-V measurement, the electrical conductance increased as the films annealed at higher temperature.

Effect of solvent medium on the structural, morphological and optical properties of ZnO nanoparticles synthesized by the sol–gel method

Energy Technology Data Exchange (ETDEWEB)

Ungula, J., E-mail: ungulaj@qwa.ufs.ac.za; Dejene, B.F.

2016-01-01

ZnO nanoparticles were synthesized using a sol–gel method. The effect of solvent medium on the structural, morphological and optical properties of ZnO nanoparticles were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence spectroscopy (PL), UV–vis spectroscopy (UV–vis) and Energy-dispersive X-ray spectroscopy ( EDS). The XRD patterns showed single phase hexagonal structure. The crystallite size of as prepared ZnO nanoparticles was found to decrease from 28.1 nm to 10.8 nm with the increase in volume ratio of ethanol in the solvent as peak intensities and sharpness increase with corresponding increase in volume ratio of water. SEM micrographs showed that samples prepared in water medium are fairly spherical which turned to tiny rods with increasing volume ratios of ethanol. A sharp ultraviolet (UV) emission peak centred about 385 nm and a broad green–yellow emission at about 550 nm are observed with PL measurements. The band gap of ZnO decreased from 3.31 to 3.17 eV with an increase in the ethanol composition in the solvent, implying that the optical properties of these materials are clearly affected by the synthesis medium.

Size and shape-dependent cytotoxicity profile of gold nanoparticles for biomedical applications.

Science.gov (United States)

Woźniak, Anna; Malankowska, Anna; Nowaczyk, Grzegorz; Grześkowiak, Bartosz F; Tuśnio, Karol; Słomski, Ryszard; Zaleska-Medynska, Adriana; Jurga, Stefan

2017-06-01

Metallic nanoparticles, in particular gold nanoparticles (AuNPs), offer a wide spectrum of applications in biomedicine. A crucial issue is their cytotoxicity, which depends greatly on various factors, including morphology of nanoparticles. Because metallic nanoparticles have an effect on cell membrane integrity, their shape and size may affect the viability of cells, due to their different geometries as well as physical and chemical interactions with cell membranes. Variations in the size and shape of gold nanoparticles may indicate particular nanoparticle morphologies that provide strong cytotoxicity effects. Synthesis of different sized and shaped bare AuNPs was performed with spherical (~ 10 nm), nanoflowers (~ 370 nm), nanorods (~ 41 nm), nanoprisms (~ 160 nm) and nanostars (~ 240 nm) morphologies. These nanostructures were characterized and interacting with cancer (HeLa) and normal (HEK293T) cell lines and cell viability tests were performed by WST-1 tests and fluorescent live/dead cell imaging experiments. It was shown that various shapes and sizes of gold nanostructures may affect the viability of the cells. Gold nanospheres and nanorods proved to be more toxic than star, flower and prism gold nanostructures. This may be attributed to their small size and aggregation process. This is the first report concerning a comparison of cytotoxic profile in vitro with a wide spectrum of bare AuNPs morphology. The findings show their possible use in biomedical applications.

Alterations of morphology of lymphoid organs and peripheral blood indicators under the influence of gold nanoparticles in rats

Directory of Open Access Journals (Sweden)

Alla B. Bucharskaya

2016-01-01

Full Text Available At present, gold nanoparticles (GNPs are widely used in biomedical applications such as cancer diagnostics and therapy. Accordingly, the potential toxicity hazards of these nanomaterials and human safety concerns are gaining significant attention. Here, we report the effects of prolonged peroral administration of GNPs with different sizes (2, 15 and 50nm on morphological changes in lymphoid organs and indicators of peripheral blood of laboratory animals. The experiment was conducted on 24 white mongrel male rats weighing 180–220g, gold nanospheres sizes 2, 15 and 50nm were administered orally for 15 days at a dosage of 190μg/kg of animal body weight. The GNPs were conjugated with polyethylene glycol to increase their biocompatibility and bioavailability. The size-dependent decrease of the number of neutrophils and lymphocytes was noted in the study of peripheral blood, especially pronounced after administration of GNPs with size of 50nm. The stimulation of myelocytic germ of hematopoiesis was recorded at morphological study of the bone marrow. The signs of strengthening of the processes of differentiation and maturation of cellular elements were found in lymph nodes, which were showed as the increasing number of immunoblasts and large lymphocytes. The quantitative changes of cellular component morphology of lymphoid organs due to activation of migration, proliferation and differentiation of immune cells indicate the presence of immunostimulation effect of GNPs.

Standardization of Nanoparticle Characterization: Methods for Testing Properties, Stability, and Functionality of Edible Nanoparticles.

Science.gov (United States)

McClements, Jake; McClements, David Julian

2016-06-10

There has been a rapid increase in the fabrication of various kinds of edible nanoparticles for oral delivery of bioactive agents, such as those constructed from proteins, carbohydrates, lipids, and/or minerals. It is currently difficult to compare the relative advantages and disadvantages of different kinds of nanoparticle-based delivery systems because researchers use different analytical instruments and protocols to characterize them. In this paper, we briefly review the various analytical methods available for characterizing the properties of edible nanoparticles, such as composition, morphology, size, charge, physical state, and stability. This information is then used to propose a number of standardized protocols for characterizing nanoparticle properties, for evaluating their stability to environmental stresses, and for predicting their biological fate. Implementation of these protocols would facilitate comparison of the performance of nanoparticles under standardized conditions, which would facilitate the rational selection of nanoparticle-based delivery systems for different applications in the food, health care, and pharmaceutical industries.

Synthesis of NiO-TiO2 hybrids/mSiO2 yolk-shell architectures embedded with ultrasmall gold nanoparticles for enhanced reactivity

Science.gov (United States)

Fang, Jiasheng; Zhang, Yiwei; Zhou, Yuming; Zhao, Shuo; Zhang, Chao; Huang, Mengqiu; Gao, Yan

2017-08-01

Novel NiO-TiO2 hybrids/mSiO2 yolk-shell architectures loaded with ultrasmall Au nanoparticles (STNVS-Au) were developed via the rational synthetic strategy. The hierarchical yolk-shell nanostructures (STNVS) with high surface areas were constructed by a facile "bottom-up" assembly process using SiO2 materials and polymer resins as cores/shells and sacrificial templates, accompanied by a simple hydrothermal incorporation of NiO into uniform amorphous TiO2 layers that were converted to NiO-anatase TiO2 p-n heterojunction hybrids. Then, numerous sub-3 nm Au nanoparticles were post encapsulated within STNVS nanostructures through the low-temperature hydrogen reduction based on the unique deposition-precipitation method with Au(en)2Cl3 compounds as gold precursors. The NiO-TiO2 hybrids alloying with Au nanoparticles were effectively protected and entrapped within STNVS architectures, and interacted with outer mSiO2-Au shells, which comprised the powerful STNVS-Au yolk-shell nanoreactors and produced stronger configural synergies in enhancing the heterogeneous catalysis. Into catalyzing the reduction of 4-nitrophenol to 4-aminophenol, the STNVS-Au was shown with outstanding activity and reusability, and its pristine morphology was well retained during the recycling process.

Applications of hierarchically structured porous materials from energy storage and conversion, catalysis, photocatalysis, adsorption, separation, and sensing to biomedicine.

Science.gov (United States)

Sun, Ming-Hui; Huang, Shao-Zhuan; Chen, Li-Hua; Li, Yu; Yang, Xiao-Yu; Yuan, Zhong-Yong; Su, Bao-Lian

2016-06-13

Over the last decade, significant effort has been devoted to the applications of hierarchically structured porous materials owing to their outstanding properties such as high surface area, excellent accessibility to active sites, and enhanced mass transport and diffusion. The hierarchy of porosity, structural, morphological and component levels in these materials is key for their high performance in all kinds of applications. The introduction of hierarchical porosity into materials has led to a significant improvement in the performance of materials. Herein, recent progress in the applications of hierarchically structured porous materials from energy conversion and storage, catalysis, photocatalysis, adsorption, separation, and sensing to biomedicine is reviewed. Their potential future applications are also highlighted. We particularly dwell on the relationship between hierarchically porous structures and properties, with examples of each type of hierarchically structured porous material according to its chemical composition and physical characteristics. The present review aims to open up a new avenue to guide the readers to quickly obtain in-depth knowledge of applications of hierarchically porous materials and to have a good idea about selecting and designing suitable hierarchically porous materials for a specific application. In addition to focusing on the applications of hierarchically porous materials, this comprehensive review could stimulate researchers to synthesize new advanced hierarchically porous solids.

A bio-inspired N-doped porous carbon electrocatalyst with hierarchical superstructure for efficient oxygen reduction reaction

Science.gov (United States)

Miao, Yue-E.; Yan, Jiajie; Ouyang, Yue; Lu, Hengyi; Lai, Feili; Wu, Yue; Liu, Tianxi

2018-06-01

The bio-inspired hierarchical "grape cluster" superstructure provides an effective integration of one-dimensional carbon nanofibers (CNF) with isolated carbonaceous nanoparticles into three-dimensional (3D) conductive frameworks for efficient electron and mass transfer. Herein, a 3D N-doped porous carbon electrocatalyst consisting of carbon nanofibers with grape-like N-doped hollow carbon particles (CNF@NC) has been prepared through a simple electrospinning strategy combined with in-situ growth and carbonization processes. Such a bio-inspired hierarchically organized conductive network largely facilitates both the mass diffusion and electron transfer during the oxygen reduction reactions (ORR). Therefore, the metal-free CNF@NC catalyst demonstrates superior catalytic activity with an absolute four-electron transfer mechanism, strong methanol tolerance and good long-term stability towards ORR in alkaline media.

Mechanistic aspects of biogenic synthesis of CdS nanoparticles using Bacillus licheniformis

International Nuclear Information System (INIS)

Tripathi, R M; Shrivastav, Archana; Bhadwal, Akhshay Singh; Singh, Priti; Singh, M P; Shrivastav, B R

2014-01-01

A novel eco-friendly effort has been made for the synthesis of cadmium sulfide (CdS) nanoparticles using bacterial biomass. Although some articles have been reported on CdS nanoparticles synthesis by bacteria, here we have synthesized CdS nanoparticles using non-pathogenic bacteria Bacillus licheniformis MTCC 9555. UV-Vis spectroscopy was carried out to confirm the formation of CdS nanoparticles; the peak occurring at 368 nm gives the indication of synthesis of CdS nanoparticles. The size and morphology of the synthesized CdS nanoparticles were analyzed by transmission electron microscopy (TEM) and the nanoparticles are found to have a narrow size of 5.1 ± 0.5 nm with spherical morphology. Further, the nanoparticles were examined by energy dispersive x-ray (EDX) spectroscopy to identify the presence of elements and confirmed the existence of Cd and S in single nanoparticles. X-ray diffraction (XRD) analysis exhibited 2θ values corresponding to CdS nanocrystals. Fourier transform infrared spectroscopy (FTIR) provides the evidence for the presence of proteins as possible biomolecules responsible for the stabilization of the synthesized CdS nanoparticles. (papers)

Biosynthesis of Metal Nanoparticles: A Review

International Nuclear Information System (INIS)

Kulkarni, N.; Muddapur, U.

2014-01-01

The synthesis of nano structured materials, especially metallic nanoparticles, has accrued utmost interest over the past decade owing to their unique properties that make them applicable in different fields of science and technology. The limitation to the use of these nanoparticles is the paucity of an effective method of synthesis that will produce homogeneous size and shape nanoparticles as well as particles with limited or no toxicity to the human health and the environment. The biological method of nanoparticle synthesis is a relatively simple, cheap, and environmentally friendly method than the conventional chemical method of synthesis and thus gains an upper hand. The bio mineralization of nanoparticles in protein cages is one of such biological approaches used in the generation of nanoparticles. This method of synthesis apart from being a safer method in the production of nanoparticles is also able to control particle morphology.

Biosynthesis of Metal Nanoparticles: A Review

Directory of Open Access Journals (Sweden)

Narendra Kulkarni

2014-01-01

Full Text Available The synthesis of nanostructured materials, especially metallic nanoparticles, has accrued utmost interest over the past decade owing to their unique properties that make them applicable in different fields of science and technology. The limitation to the use of these nanoparticles is the paucity of an effective method of synthesis that will produce homogeneous size and shape nanoparticles as well as particles with limited or no toxicity to the human health and the environment. The biological method of nanoparticle synthesis is a relatively simple, cheap, and environmentally friendly method than the conventional chemical method of synthesis and thus gains an upper hand. The biomineralization of nanoparticles in protein cages is one of such biological approaches used in the generation of nanoparticles. This method of synthesis apart from being a safer method in the production of nanoparticles is also able to control particle morphology.

Effect of precursor supply on structural and morphological characteristics of fe nanomaterials synthesized via chemical vapor condensation method.

Science.gov (United States)

Ha, Jong-Keun; Ahn, Hyo-Jun; Kim, Ki-Won; Nam, Tae-Hyun; Cho, Kwon-Koo

2012-01-01

Various physical, chemical and mechanical methods, such as inert gas condensation, chemical vapor condensation, sol-gel, pulsed wire evaporation, evaporation technique, and mechanical alloying, have been used to synthesize nanoparticles. Among them, chemical vapor condensation (CVC) has the benefit of its applicability to almost all materials because a wide range of precursors are available for large-scale production with a non-agglomerated state. In this work, Fe nanoparticles and nanowires were synthesized by chemical vapor condensation method using iron pentacarbonyl (Fe(CO)5) as the precursor. The effect of processing parameters on the microstructure, size and morphology of Fe nanoparticles and nanowires were studied. In particular, we investigated close correlation of size and morphology of Fe nanoparticles and nanowires with atomic quantity of inflow precursor into the electric furnace as the quantitative analysis. The atomic quantity was calculated by Boyle's ideal gas law. The Fe nanoparticles and nanowires with various diameter and morphology have successfully been synthesized by the chemical vapor condensation method.

Ecosystem protection by effluent bioremediation: silver nanoparticles impregnation in a textile fabrics process

International Nuclear Information System (INIS)

Duran, Nelson; Marcato, Priscyla D.; Alves, Oswaldo L.; Silva, Joao P. S. Da; Souza, Gabriel I. H. De; Rodrigues, Flavio A.; Esposito, Elisa

2010-01-01

This work studied a bioremediation process of silver nanoparticles with the bacterium Chromobacterium violaceum. These nanoparticles were obtained from several washes of cotton fabrics impregnated with silver nanoparticles produced by the fungus Fusarium oxysporum. The optimized growth of C. violaceum for silver nanoparticles bioremediation was obtained. The effluents of wash process of the cotton fabric were efficiently treated with C. violaceum. This treatment was based on biosorption which was very efficient for the elimination of silver nanoparticles remaining in the wash water. The bacteria after biosorption were morphologically transformed, but the normal morphology after a new culture was completely restored. The process also allowed the recovery of silver material that was leached into the effluent for a reutilization avoiding any effect to the eco-environment.

Ecosystem protection by effluent bioremediation: silver nanoparticles impregnation in a textile fabrics process

Energy Technology Data Exchange (ETDEWEB)

Duran, Nelson, E-mail: duran@iqm.unicamp.br; Marcato, Priscyla D. [Universidade Estadual de Campinas, Biological Chemistry Laboratory, Instituto de Quimica (Brazil); Alves, Oswaldo L. [Universidade Estadual de Campinas, Solid State Chemistry Laboratory, Instituto de Quimica (Brazil); Silva, Joao P. S. Da; Souza, Gabriel I. H. De [Universidade de Mogi das Cruzes, Biological Chemistry and Biotechnology Laboratory, Environmental Sciences Center (Brazil); Rodrigues, Flavio A. [Universidade de Mogi das Cruzes, Material Chemistry Laboratory, Biochemical Research Center (Brazil); Esposito, Elisa [Universidade de Mogi das Cruzes, Biological Chemistry and Biotechnology Laboratory, Environmental Sciences Center (Brazil)

2010-01-15

This work studied a bioremediation process of silver nanoparticles with the bacterium Chromobacterium violaceum. These nanoparticles were obtained from several washes of cotton fabrics impregnated with silver nanoparticles produced by the fungus Fusarium oxysporum. The optimized growth of C. violaceum for silver nanoparticles bioremediation was obtained. The effluents of wash process of the cotton fabric were efficiently treated with C. violaceum. This treatment was based on biosorption which was very efficient for the elimination of silver nanoparticles remaining in the wash water. The bacteria after biosorption were morphologically transformed, but the normal morphology after a new culture was completely restored. The process also allowed the recovery of silver material that was leached into the effluent for a reutilization avoiding any effect to the eco-environment.

ODS - modified TiO2 nanoparticles for the preparation of self-cleaning superhydrophobic coating

Science.gov (United States)

Kokare, Ashvini M.; Sutar, Rajaram S.; Deshmukh, S. G.; Xing, Ruimin; Liu, Shanhu; Latthe, Sanjay S.

2018-05-01

Rolling water drops takes off dust particles from lotus leaf showing self-cleaning performance. Self-cleaning effect has great importance in industry as well as in daily life. The present paper describes the preparation of self-cleaning superhydrophobic coating through simple and low cost dip coating technique. The prepared superhydrophobic surface enact as lotus leaf. Firstly TiO2 nanoparticles were dispersed in ethanol and different concentration of octadecyltrichlorosilane (ODS) was added in TiO2 dispersion. The effect of number of deposition layer on the wettability of the coating was studied. The coating prepared from five deposition layers showed contact angle higher than 150° and sliding angle less than 10°. The superhydrophobicity increases with increasing concentration of ODS. The hierarchical rough morphology which is preferable for superhydrophobicity was obtained. The prepared coatings were stable against water jet impact and showed repellent towards colored and muddy water. Such superhydrophobic coating can find enormous scope in self-cleaning application.

Recent advances in cryo-TEM imaging of soft lipid nanoparticles

DEFF Research Database (Denmark)

Helvig, Shen Yu; Mat Azmi, Intan Diana Binti; Moghimi, Seyed Moien

2015-01-01

Cryo-transmission electron microscopy (Cryo-TEM), and its technological variations thereof, have become a powerful tool for detailed morphological characterization and 3D tomography of soft lipid and polymeric nanoparticles as well as biological materials such as viruses and DNA without chemical...... fixation. Here, we review and discuss recent advances in Cryo-TEM analysis of lipid-based drug nanocarriers with particular emphasis on morphological and internal nanostructure characterization of lyotropic liquid crystalline nanoparticles such as cubosomes and hexosomes....

Evaluation of cytotoxicity of polypyrrole nanoparticles synthesized by oxidative polymerization

Energy Technology Data Exchange (ETDEWEB)

Vaitkuviene, Aida [Department of Physical Chemistry, Faculty of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Department of Stem Cell Biology, State Research Institute Center for Innovative Medicine, Zygimantu 9, LT-01102 Vilnius (Lithuania); Kaseta, Vytautas [Department of Stem Cell Biology, State Research Institute Center for Innovative Medicine, Zygimantu 9, LT-01102 Vilnius (Lithuania); Voronovic, Jaroslav [Department of Physical Chemistry, Faculty of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Ramanauskaite, Giedre; Biziuleviciene, Gene [Department of Stem Cell Biology, State Research Institute Center for Innovative Medicine, Zygimantu 9, LT-01102 Vilnius (Lithuania); Ramanaviciene, Almira [NanoTechnas–Center of Nanotechnology and Material Science at Department of Analytical and Environmental Chemistry, Faculty of Chemistry, Vilnius University, Naugarduko 24, 03225 Vilnius (Lithuania); Ramanavicius, Arunas, E-mail: Arunas.Ramanavicius@chf.vu.lt [Department of Physical Chemistry, Faculty of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Laboratory of BioNanoTechnology, Department of Materials Science and Electronics, Institute of Semiconductor Physics, State Scientific Research Institute Centre for Physical Sciences and Technology, A. Gostauto 11, LT-01108 Vilnius (Lithuania)

2013-04-15

Highlights: ► Polypyrrole nanoparticles synthesized by environmentally friendly polymerization at high concentrations are cytotoxic. ► Primary mouse embryonic fibroblast, mouse hepatoma and human T lymphocyte Jurkat cell lines were treated by Ppy nanoparticles. ► Polypyrrole nanoparticles at high concentrations inhibit cell proliferation. -- Abstract: Polypyrrole (Ppy) is known as biocompatible material, which is used in some diverse biomedical applications and seeming to be a very promising for advanced biotechnological applications. In order to increase our understanding about biocompatibility of Ppy, in this study pure Ppy nanoparticles (Ppy-NPs) of fixed size and morphology were prepared by one-step oxidative polymerization and their cyto-compatibility was evaluated. The impact of different concentration of Ppy nanoparticles on primary mouse embryonic fibroblasts (MEF), mouse hepatoma cell line (MH-22A), and human T lymphocyte Jurkat cell line was investigated. Cell morphology, viability/proliferation after the treatment by Ppy nanoparticles was evaluated. Obtained results showed that Ppy nanoparticles at low concentrations are biocompatible, while at high concentrations they became cytotoxic for Jurkat, MEF and MH-22A cells, and it was found that cytotoxic effect is dose-dependent.

Stability and morphology of Ag nanoplatelets probed by depolarized dynamic light scattering

Science.gov (United States)

Zimbone, M.; Contino, A.; Maccarrone, G.; Musumeci, P.; Lo Faro, M. J.; Calcagno, L.

2018-06-01

The stability of silver nanoplatelet (NP) suspensions prepared with different concentrations of trisodium citrate (TSC) was studied by depolarized dynamic light scattering (DDLS) and UV–vis spectrometry. The morphology of the nanoparticles, as well as the color and stability of the sols, are tuned by the concentration of the capping agent. The nanoparticles prepared with high TSC concentration (>10‑4 M) are blue triangular NPs showing a slight truncation of the tips with aging. When low TSC concentrations are used, the color of the sols changes from blue to yellow with aging time and a strong modification of the morphology occurs: the nanoparticle shape changes from triangular to spherical. Remarkably, they show a high degree of anisotropy. The aging process was followed by the UV–vis spectra and by measuring the rotational diffusion coefficient by DDLS, providing information on the nanoparticle size and shape evolution. The high intensity of depolarized signal and the high value of rotational diffusion coefficient suggest that the aging process increases the thickness and the roughness of the nanoparticles

Effect of surfactant amount on the morphology and magnetic properties of monodisperse ZnFe{sub 2}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Zhao, Haitao, E-mail: zht95711lunwen@163.com; Liu, Ruiping; Zhang, Qiang; Wang, Qiao

2016-03-15

Graphical abstract: Polyol process to monodisperse ZnFe{sub 2}O{sub 4} nanoparticles. - Highlights: • An one-step, facile and inexpensive synthetic route to monodisperse ZnFe{sub 2}O{sub 4} nanoparticles is described. • The sodium citrate stabilized ZnFe{sub 2}O{sub 4} nanoparticles with a diameter in the 5–8 nm size range can be easily dispersed in water. • The synthesis is very robust in terms of variations of experimental parameters. • ZnFe{sub 2}O{sub 4} nanoparticles present ferrimagnetic behavior at room temperature with a small hysteresis. - Abstract: The spinel ZnFe{sub 2}O{sub 4} ferrites with sodium citrate as a surfactant were fabricated by polyol process. The effect of surfactant amount on the structure, morphology and magnetic properties of ZnFe{sub 2}O{sub 4} ferrites were investigated by X-ray diffraction(XRD), transmission electron microscope (TEM), thermogravimetric and differential scanning calorimetry (TG–DSC) and vibrating sample magnetometry (VSM), respectively. The results indicate that the structure of ZnFe{sub 2}O{sub 4} ferrites is a pure cubic spinel structure with a particle size of 5–8 nm. The dispersion of the synthesized ZnFe{sub 2}O{sub 4} is enhanced when the mole ratio of Fe(acac){sub 3} to sodium citrate decreases. The synthesized particles present ferrimagnetic behavior with a small hysteresis at room temperature. The increase of surfactant amount conversely leads to the decrease in the saturation magnetization value (Ms) especially when the mole ratio of Fe(acac){sub 3} to sodium citrate decreases to 8:3. Its Ms value is drastically reduced to 18.97 emu/g.

Evaluation of cellular influences caused by calcium carbonate nanoparticles.

Science.gov (United States)

Horie, Masanori; Nishio, Keiko; Kato, Haruhisa; Endoh, Shigehisa; Fujita, Katsuhide; Nakamura, Ayako; Kinugasa, Shinichi; Hagihara, Yoshihisa; Yoshida, Yasukazu; Iwahashi, Hitoshi

2014-03-05

The cellular effects of calcium carbonate (CaCO₃) nanoparticles were evaluated. Three kinds of CaCO₃ nanoparticles were employed in our examinations. One of the types of CaCO₃ nanoparticles was highly soluble. And solubility of another type of CaCO₃ nanoparticle was lower. A stable CaCO₃ nanoparticle medium dispersion was prepared and applied to human lung carcinoma A549 cells and human keratinocyte HaCaT cells. Then, mitochondrial activity, cell membrane damage, colony formation ability, DNA injury, induction of oxidative stress, and apoptosis were evaluated. Although the influences of CaCO₃ nanoparticles on mitochondrial activity and cell membrane damage were small, "soluble" CaCO₃ nanoparticles exerted some cellular influences. Soluble CaCO₃ nanoparticles also induced a cell morphological change. Colony formation was inhibited by CaCO₃ nanoparticle exposure. In particular, soluble CaCO₃ nanoparticles completely inhibited colony formation. The influence on intracellular the reactive oxygen species (ROS) level was small. Soluble CaCO₃ nanoparticles caused an increase in C/EBP-homologous protein (CHOP) expression and the activation of caspase-3. Moreover, CaCO₃ exposure increased intracellular the Ca²⁺ level and activated calpain. These results suggest that cellular the influences of CaCO₃ nanoparticles are mainly caused by intracellular calcium release and subsequently disrupt the effect of calcium signaling. In conclusion, there is possibility that soluble CaCO₃ nanoparticles induce cellular influences such as a cell morphological change. Cellular influence of CaCO₃ nanoparticles is caused by intracellular calcium release. If inhaled CaCO₃ nanoparticles have the potential to influence cellular events. However, the effect might be not severe because calcium is omnipresent element in cell. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Study on dependence of dose enhancement on cluster morphology of gold nanoparticles in radiation therapy using a body-centred cubic model

Science.gov (United States)

Ahn, Sang Hee; Chung, Kwangzoo; Shin, Jung Wook; Cheon, Wonjoong; Han, Youngyih; Park, Hee Chul; Choi, Doo Ho

2017-10-01

Gold nanoparticles (GNPs) injected in a body for dose enhancement in radiation therapy are known to form clusters. We investigated the dependence of dose enhancement on the GNP morphology using Monte-Carlo simulations and compared the model predictions with experimental data. The cluster morphology was approximated as a body-centred cubic (BCC) structure by placing GNPs at the 8 corners and the centre of a cube with an edge length of 0.22-1.03 µm in a 4  ×  4  ×  4 µm3 water-filled phantom. We computed the dose enhancement ratio (DER) for 50 and 260 kVp photons as a function of the distance from the cube centre for 12 different cube sizes. A 10 nm-wide concentric shell shaped detector was placed up to 100 nm away from a GNP at the cube centre. For model validation, simulations based on BCC and nanoparticle random distribution (NRD) models were performed using parameters that corresponded to the experimental conditions, which measured increases in the relative biological effect due to GNPs. We employed the linear quadratic model to compute cell surviving fraction (SF) and sensitizer enhancement ratio (SER). The DER is inversely proportional to the distance to the GNPs. The largest DERs were 1.97 and 1.80 for 50 kVp and 260 kVp photons, respectively. The SF predicted by the BCC model agreed with the experimental value within 10%, up to a 5 Gy dose, while the NRD model showed a deviation larger than 10%. The SERs were 1.21  ±  0.13, 1.16  ±  0.11, and 1.08  ±  0.11 according to the experiment, BCC, and NRD models, respectively. We most accurately predicted the GNP radiosensitization effect using the BCC approximation and suggest that the BCC model is effective for use in nanoparticle dosimetry.

Polypropylene Nano composites Obtained by In Situ Polymerization Using Metallocenes Catalyst: Influence of the Nanoparticles on the Final Polymer Morphology

International Nuclear Information System (INIS)

Zapata, P.; Quijada, R.

2012-01-01

Polypropylene nano composites containing silica nanospheres based on the sol-gel methods were produced via in situ polymerization using a rac-Et(Ind) 2 ZrCl 2 /methylaluminoxane (MAO) system. Two different routes were used depending on the interaction between the silica nanoparticles with the catalytic system. In route 1 the nanoparticles were added together with the catalytic system (rac-Et(Ind) 2 ZrCl 2 )/(MAO) directly into the reactor, and in route 2 the metallocenes rac-Et(Ind) 2 ZrCl 2 was supported on silica nanospheres pretreated with (MAO). SEM images show that when the nanospheres were added by both routes, they were replicated in the final polymer particle morphology; this phenomenon was more pronounced for PP obtained by route 2. The polypropylene (PP) nano composites obtained by both routes had a slightly higher percent crystallinity and crystallinity temperatures than pure PP. Transmission electron microscopy (TEM) images show that the nanospheres were well dispersed into the polypropylene matrix, particularly in the nano composites obtained by the support system (route 2).

Phytosynthesis and Characterization of Silver Nanoparticles Using Callus of JATROPHA CURCAS: a Biotechnological Approach

Science.gov (United States)

Demissie, A. G.; Lele, S. S.

2013-06-01

The present study reports a rapid plant-based biosynthesis of silver nanoparticles using callus extract of Jatropha curcas L. The particle size and morphological analyses were carried out using Zetasizer, SEM, TEM. The physicochemical properties were monitored using UV-Vis spectroscopic, IR and DSC. The formation of silver nanoparticle was confirmed by using UV-Vis spectrophotometer and absorbance peaks at 421 nm. The silver nanoparticle was found to be a negatively charged with size ranging from 2 nm to 50 nm. The morphology of the nanoparticle is uniformly spherical and has a dispersion ratio of 0.14. The physicochemical study using DSC indicated significant thermal stability and crystalline nature of the nanoparticle. This intracellular biosynthesis of silver nanoparticles is simple, cheap and eco-friendly than other mechanical and chemical approaches.

Graphene Edges Dictate the Morphology of Nanoparticles during Catalytic Channeling

DEFF Research Database (Denmark)

Pizzocchero, Filippo; Vanin, Marco; Kling, Jens

2014-01-01

We perform in-situ transmission electron microscopy (TEM) experiments of silver nanoparticles channeling on mono-, bi-, and few-layer graphene and discover that the interactions in the one-dimensional particle–graphene contact line are sufficiently strong so as to dictate the three-dimensional sh......We perform in-situ transmission electron microscopy (TEM) experiments of silver nanoparticles channeling on mono-, bi-, and few-layer graphene and discover that the interactions in the one-dimensional particle–graphene contact line are sufficiently strong so as to dictate the three......-dimensional shape of the nanoparticles. We find a characteristic faceted shape in particles channeling along graphene ⟨100⟩ directions that is lost during turning and thus represents a dynamic equilibrium state of the graphene–particle system. We propose a model for the mechanism of zigzag edge formation...... and an explanation of the rate-limiting step for this process, supported by density functional theory (DFT) calculations, and obtain a good agreement between the DFT-predicted and experimentally obtained activation energies of 0.39 and 0.56 eV, respectively. Understanding the origin of the channels' orientation...

Hierarchical porous carbon/MnO2 hybrids as supercapacitor electrodes.

Science.gov (United States)

Lee, Min Eui; Yun, Young Soo; Jin, Hyoung-Joon

2014-12-01

Hybrid electrodes of hierarchical porous carbon (HPC) and manganese oxide (MnO2) were synthesized using a fast surface redox reaction of potassium permanganate under facile immersion methods. The HPC/MnO2 hybrids had a number of micropores and macropores and the MnO2 nanoparticles acted as a pseudocapacitive material. The synergistic effects of electric double-layer capacitor (EDLC)-induced capacitance and pseudocapacitance brought about a better electrochemical performance of the HPC/MnO2 hybrid electrodes compared to that obtained with a single component. The hybrids showed a specific capacitance of 228 F g(-1) and good cycle stability over 1000 cycles.

Characterizing Nanoparticles Reactivity: Structure-Photocatalytic Activity Relationship

International Nuclear Information System (INIS)

Piella, J; Bastús, N G; Casals, E; Puntes, V

2013-01-01

Nanoparticles are reactive, and their final interactions with the surrounding media are ultimately determined by their reactivity, which in turns depends on the nanoparticles morphology, surface chemistry and environment in which they are embedded. One simple and informative approach for the study of the reactivity of nanoparticles is the determination of their photocatalytic activity. In the present work, we briefly summarize the importance of different parameters such as the size, shape and agglomeration state on the photocatalytic activity of colloidal inorganic nanoparticles. The study of the use of nanoparticles as photocatalyts is relevant not only for its potential applications in environmental remediation issues but also it can provide relevant information about the role of these parameters at the nanoscale.

Electrostatics-Driven Hierarchical Buckling of Charged Flexible Ribbons.

Science.gov (United States)

Yao, Zhenwei; Olvera de la Cruz, Monica

2016-04-08

We investigate the rich morphologies of an electrically charged flexible ribbon, which is a prototype for many beltlike structures in biology and nanomaterials. Long-range electrostatic repulsion is found to govern the hierarchical buckling of the ribbon from its initially flat shape to its undulated and out-of-plane twisted conformations. In this process, the screening length is the key controlling parameter, suggesting that a convenient way to manipulate the ribbon morphology is simply to change the salt concentration. We find that these shapes originate from the geometric effect of the electrostatic interaction, which fundamentally changes the metric over the ribbon surface. We also identify the basic modes by which the ribbon reshapes itself in order to lower the energy. The geometric effect of the physical interaction revealed in this Letter has implications for the shape design of extensive ribbonlike materials in nano- and biomaterials.

Role of dipolar interactions on morphologies and tunnel magnetoresistance in assemblies of magnetic nanoparticles

Science.gov (United States)

Anand, Manish; Carrey, Julian; Banerjee, Varsha

2018-05-01

We undertake comprehensive simulations of 2d arrays (Lx ×Ly) of magnetic nanoparticles (MNPs) with dipole-dipole interactions by solving LLG equations. Our primary interest is to understand the correspondence between equilibrium spin (ES) morphologies and tunnel magnetoresistance (TMR) as a function of Θ - the ratio of the dipolar to the anisotropy strength, sample size Lx , aspect ratio Ar =Ly /Lx and the direction of the applied field H → = HêH . The parameter Θ is varied by choosing three distinct particles: (i) α -Fe2O3 (Θ ≃ 0) , (ii) Co (Θ ≃ 0.37) and (iii) Fe3O4 (Θ ≃ 1.28) . Our main observations are as follows: (a) For weakly interacting spins (Θ ≃ 0) , the morphology has randomly oriented magnetic moments for all sample sizes and aspect ratios. The TMR exhibits a peak value of 50% at the coercive field Hc . It is robust with respect to Lx and Ar , and isotropic with respect to êH . (b) For strong interactions (Θ > 1) , the moments order in the plane of the sample. The ES morphology comprises of magnetically aligned regions interspersed with flux closure loops. For fields along x or y, the maximum TMR amplitude decrease to ∼30%. For êH = z ̂ , it drops to ∼3%. The TMR is robust with respect to Lx and Ar and isotropic in the x and y directions only. (c) In strongly interacting samples (Θ > 1) with Lx comparable to the size of a flux closure loop, increasing Ar creates ferromagnetic chains in the sample oriented along y or - y . Consequently, for êH = y ̂ , the TMR magnitude for Ar = 1 is ∼33% while that for Ar = 32 drops to ∼16%. For êH = x ̂ on the other hand, it is ∼30% and independent of Ar . The TMR of long ribbons of MNPs has a strong dependence on Ar and is anisotropic in all three directions.

Microemulsion synthesis and magnetic properties of FexNi(1-x) alloy nanoparticles

Science.gov (United States)

Beygi, H.; Babakhani, A.

2017-01-01

This paper investigates synthesis of FexNi(1-x) bimetallic nanoparticles by microemulsion method. Through studying the mechanism of nanoparticles formation, it is indicated that synthesis of nanoparticles took placed by simultaneous reduction of metal ions and so nanoparticles structure is homogeneous alloy. FexNi(1-x) nanoparticles with different sizes, morphologies and compositions were synthesized by changing the microemulsion parameters such as water/surfactant/oil ratio, presence of co-surfactant and NiCl2·6H2O to FeCl2·4H2O molar ratio. Synthesized nanoparticles were characterized by transmission electron microscopy, particle size analysis, X-ray diffraction, atomic absorption and thermogravimetric analyses. The results indicated that, presence of butanol as co-surfactant led to chain-like arrangement of nanoparticles. Also, finer nanoparticles were synthesized by decreasing the amount of oil and water and increasing the amount of CTAB. The results of vibrating sample magnetometer suggested that magnetic properties of FexNi(1-x) alloy nanoparticles were affected by composition, size and morphology of the particles. Spherical and chain-like FexNi(1-x) alloy nanoparticles were superparamagnetic and ferromagnetic, respectively. Furthermore, higher iron in the composition of nanoparticles increases the magnetic properties.

Electrospun alginate nanofibres impregnated with silver nanoparticles: Preparation, morphology and antibacterial properties

CSIR Research Space (South Africa)

Mokhena, Teboho M

2017-06-01

Full Text Available . In this study, silver nanoparticles (AgNPs) have been synthesized using chitosan as reducing and stabilizing agent. The formation of silver nanoparticles was confirmed by UV-vis, and the TEM showed that different shapes were obtained depending on the heating...

SIMS depth profiling of working environment nanoparticles

Science.gov (United States)

Konarski, P.; Iwanejko, I.; Mierzejewska, A.

2003-01-01

Morphology of working environment nanoparticles was analyzed using sample rotation technique in secondary ion mass spectrometry (SIMS). The particles were collected with nine-stage vacuum impactor during gas tungsten arc welding (GTAW) process of stainless steel and shielded metal arc welding (SMAW) of mild steel. Ion erosion of 300-400 nm diameter nanoparticles attached to indium substrate was performed with 2 keV, 100 μm diameter, Ar + ion beam at 45° ion incidence and 1 rpm sample rotation. The results show that both types of particles have core-shell morphology. A layer of fluorine, chlorine and carbon containing compounds covers stainless steel welding fume particles. The cores of these particles are enriched in iron, manganese and chromium. Outer shell of mild steel welding fume particles is enriched in carbon, potassium, chlorine and fluorine, while the deeper layers of these nanoparticles are richer in main steel components.

SIMS depth profiling of working environment nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Konarski, P.; Iwanejko, I.; Mierzejewska, A

2003-01-15

Morphology of working environment nanoparticles was analyzed using sample rotation technique in secondary ion mass spectrometry (SIMS). The particles were collected with nine-stage vacuum impactor during gas tungsten arc welding (GTAW) process of stainless steel and shielded metal arc welding (SMAW) of mild steel. Ion erosion of 300-400 nm diameter nanoparticles attached to indium substrate was performed with 2 keV, 100 {mu}m diameter, Ar{sup +} ion beam at 45 deg. ion incidence and 1 rpm sample rotation. The results show that both types of particles have core-shell morphology. A layer of fluorine, chlorine and carbon containing compounds covers stainless steel welding fume particles. The cores of these particles are enriched in iron, manganese and chromium. Outer shell of mild steel welding fume particles is enriched in carbon, potassium, chlorine and fluorine, while the deeper layers of these nanoparticles are richer in main steel components.

Polyaniline nanowires on TiO2 nano/microfiber hierarchical nano/microstructures: Preparation and their photocatalytic properties

International Nuclear Information System (INIS)

Yu Qiaozhen; Wang Mang; Chen Hongzheng; Dai Zhengwei

2011-01-01

Highlights: → We fabricate PANI nanowire-on-TiO 2 nano/microfiber hierarchical nano/microstructure composite fiber films by electrospinning, calcinations and in situ polymerization. → PANI/TiO 2 composite fiber film exhibits high photocatalytic activity for the degradation of dye MB. → The photocatalytic activity and reusability of PANI/TiO 2 composite fiber film were lower than those of pure TiO 2 fiber film. - Abstract: TiO 2 /PANI composite fiber films were fabricated by electrospinning, calcinations and in situ polymerization. The morphology and structure of the resulting composites were analyzed by scanning electron micrograph, transmission electron micrograph, Fourier transform infrared spectroscopy and X-ray diffraction. It was found that this composite fiber film has a PANI nanowire-on-TiO 2 nano/microfiber hierarchical nano/microstructure. The surface morphology of this hierarchical nano/microstructure was related to the structure of TiO 2 nano/microfiber film, the time and temperature of in situ polymerization. Its photocatalytic property on methylene blue (MB) was studied, and the results showed that TiO 2 /PANI composite fiber film with this hierarchical nano/microstructure exhibited high photocatalytic activity for the degradation of MB under natural light. But both its photocatalytic activity and reusability were lower than those of pure TiO 2 fiber film. To improve the stability and reusability of TiO 2 /PANI composite fiber film, a direct chemical bonding of PANI chains onto TiO 2 surface, such as, the surface-initiated graft polymerization, is a useful method.

Morphological study of fluorescent carbon Nanoparticles (F-CNPs) from ground coffee waste soot oxidation by diluted acid

Science.gov (United States)

Gea, S.; Tjandra, S.; Joshua, J.; Wirjosentono, B.

2018-02-01

Coffee ground waste utilization for fluorescent carbon nanoparticles (F-CNPs) through soot oxidation with diluted HNO3 has been conducted. Soot was obtained through three different treatments to coffee ground waste; which was burned in furnaceat 550°C and 650°C and directly burned in a heat-proofcontainer. Then they were analyzed morphologically with Scanning Electron Microscope (SEM) instrument. Soot from direct burning indicated the optimum result where it has denser pores compared to other two soots. Soot obtained from direct burning was refluxed in diluted HNO3 for 12 hours to perform the oxidation. Yellowish brown supernatant was later observed which lead to green fluorescent under the UV light. F-CNPs characterization was done in Transmission Electron Microscopy, which showed that 7.4-23.4 nm of particle size were distributed.

Magnetoelectric Coupling in CuO Nanoparticles for Spintronics Applications

Science.gov (United States)

Kaur, Mandeep; Tovstolytkin, Alexandr; Lotey, Gurmeet Singh

2018-05-01

Multiferroic copper oxide (CuO) nanoparticles have been synthesized by colloidal synthesis method. The morphological, structural, magnetic, dielectric and magnetodielectric property has been investigated. The structural study reveals the monoclinic structure of CuO nanoparticles. Transmission electron microscopy images disclose that the size of the CuO nanoparticles is 18 nm and the synthesized nanoparticles are uniform in size and dispersion. Magnetic study tells the weak ferromagnetic character of CuO nanoparticles with coercivity and retentivity value 206 Oe and 0.060 emu/g respectively. Dielectric study confirms that the dielectric constant of CuO nanoparticles is around 1091 at low frequency. The magnetoelectric coupling in the synthesized CuO nanoparticles has been calculated by measuring magnetodielectric coupling coefficient.

Preparation of curcumin nanoparticle by using reinforcement ionic gelation technique

Science.gov (United States)

Suryani, Halid, Nur Hatidjah Awaliyah; Akib, Nur Illiyyin; Rahmanpiu, Mutmainnah, Nina

2017-05-01

Curcumin, a polyphenolic compound present in curcuma longa has a wide range of activities including anti-inflammatory properties. The potency of curcumin is limited by its poor oral bioavailability because of its poor solubility in aqueous. Various methods have been tried to solve the problem including its encapsulation into nanoparticle. The aim of this study is to develop curcumin nanoparticle by using reinforcement ionic gelation technique and to evaluate the stability of curcumin nanoparticles in gastrointestinal fluid. Curcumin nanoparticles were prepared by using reinforcement ionic gelation technique with different concentrations of chitosan, trypolyphosphate, natrium alginate and calcium chloride. Curcumin nanoparticles were then characterized including particle size and zeta potential by using particle size analyzer and morphology using a transmission electron microscope, entrapment efficiency using UV-Vis Spectrophotometer and chemical structure analysis by Infra Red Spectrophotometer (FTIR). Furthermore, the stability of curcumin nanoparticles were evaluated on artificial gastric fluid and artificial intestinal fluids by measuring the amount of curcumin released in the medium at a time interval. The result revealed that curcumin nanoparticles can be prepared by reinforcement ionic gelation technique, the entrapment efficiency of curcumin nanoparticles were from 86.08 to 91.41%. The average of particle size was 272.9 nm and zeta potential was 12.05 mV. The morphology examination showed that the curcumin nanoparticles have spherical shape. The stability evaluation of curcumin nanoparticles showed that the nanoparticles were stable on artificial gastric fluid and artificial intestinal fluid. This result indicates that curcumin nanoparticles have the potential to be developed for oral delivery.