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Sample records for monodisperse polystyrene microspheres

  1. Synthesis of monodisperse crosslinked polystyrene microspheres

    Institute of Scientific and Technical Information of China (English)

    Jiang Kai; Chen Sheng-Li; Dong Peng; Liu Renxiao

    2008-01-01

    Monodisperse crosslinked polystyrene (CPS) particles were prepared through the normal emulsion polymerization method by adding crosslinker-divinylbenzene (DVB) into the reaction system after polystyrene (PS) particles grew to ~80% of the final size. When the amount of crosslinker DVB added was less than 6.17 wt% based on styrene, the prepared CPS particles were spherical and uniform and the size of the CPS particles could be predicted through the normal emulsion method. The glass transition temperature (Tg) of the prepared CPS particles was higher than that of un-crosslinked PS particles and, the more crosslinker that was added, the higher the Tg of CPS Particles. The prepared CPS particles had strong resistance to organic solvents.

  2. Growth Kinetics of Monodisperse Polystyrene Microspheres Prepared by Dispersion Polymerization

    Directory of Open Access Journals (Sweden)

    Fan Li

    2013-01-01

    Full Text Available Dispersion polymerization has been widely applied to the synthesis of monodisperse micron-sized polymer colloidal spheres. Many efforts have been devoted to studying the influence of initial conditions on the size and uniformity of the resultant microspheres, aiming to synthesize micron-size monodisperse colloidal spheres. However, the inner contradiction between the size and the size distribution of colloidal spheres hinders the realization of this goal. In this work, we drew our attention from the initial conditions to the growth stage of dispersion polymerization. We tracked the size evolution of colloidal sphere during the dispersion polymerization, through which we established a kinetic model that described the relationship between the monomer concentration and the reaction time. The model may provide a guideline to prepare large polymer colloidal spheres with good monodispersity by continuous monomer feeding during the growth stage to maintain the concentration of monomer at a constant value in a dispersion polymerization process.

  3. Facile Synthesis of Mono-Dispersed Polystyrene (PS/Ag Composite Microspheres via Modified Chemical Reduction

    Directory of Open Access Journals (Sweden)

    Wen Zhu

    2013-12-01

    Full Text Available A modified method based on in situ chemical reduction was developed to prepare mono-dispersed polystyrene/silver (PS/Ag composite microspheres. In this approach; mono-dispersed PS microspheres were synthesized through dispersion polymerization using poly-vinylpyrrolidone (PVP as a dispersant at first. Then, poly-dopamine (PDA was fabricated to functionally modify the surfaces of PS microspheres. With the addition of [Ag(NH32]+ to the PS dispersion, [Ag(NH32]+ complex ions were absorbed and reduced to silver nanoparticles on the surfaces of PS-PDA microspheres to form PS/Ag composite microspheres. PVP acted both as a solvent of the metallic precursor and as a reducing agent. PDA also acted both as a chemical protocol to immobilize the silver nanoparticles at the PS surface and as a reducing agent. Therefore, no additional reducing agents were needed. The resulting composite microspheres were characterized by TEM, field emission scanning electron microscopy (FESEM, energy-dispersive X-ray spectroscopy (EDS, XRD, UV-Vis and surface-enhanced Raman spectroscopy (SERS. The results showed that Ag nanoparticles (NPs were homogeneously immobilized onto the PS microspheres’ surface in the presence of PDA and PVP. PS/Ag composite microspheres were well formed with a uniform and compact shell layer and were adjustable in terms of their optical property.

  4. PREPARATION OF MONODISPERSE POLYSTYRENE MICROSPHERES BY SHELL POROUS GLASS-SUSPENSION POLYMERIZATION%用多孔玻璃膜管-悬浮聚合法制备单分散性聚苯乙烯微球

    Institute of Scientific and Technical Information of China (English)

    范星河; 谢晓峰

    2001-01-01

    Monodisperse polystyrene microspheres are prepared by shell porous glass(SPG)-suspension polymerization. The influences of SPG on size and size dispersity of the microspheres are investigated. The properties of the microspheres are studied by GPC, TEM and SEM. The results indicate that the polystyrene microspheres possess definite monodispersibity and their particle size is in the range of 5~12μm.

  5. Mono-dispersed cross-linked polystyrene micro-spheres prepared by seed swelling polymerization method

    Institute of Scientific and Technical Information of China (English)

    Dongsha WANG; Yanjun LIU

    2008-01-01

    A two-step swelling procedure was adopted to synthesize mono-dispersed and highly cross-linked poly (St-divinylbenzene) particles with PSt micro-spheres (1.80 μmin diameter). The PSt micro-spheres were prepared by a dispersion polymerization method and used as seeds. The effects of monomer concentration, ratio of ethanol to water, swelling reagents, crosslinking reagents, swelling temper-ature and agitation speed on particle size were investigated in detail. The morphologies and size distributions of these micro-spheres were examined by SEM and particle size analysis (PSA). The Tg of the micro-spheres was measured by DSC. The results indicate that the particles (6.20 μm in diameter) exhibit excellent mono dispersed property and high crosslinking degree when the concentration of the swelling reagent was 25%, the concentration of the cross-linking reagents was 23%, the swelling temperature was 30℃ and the stirring speed was 150 r/min.

  6. Upconversion Nanoparticles and Monodispersed Magnetic Polystyrene Microsphere Based Fluorescence Immunoassay for the Detection of Sulfaquinoxaline in Animal-Derived Foods.

    Science.gov (United States)

    Hu, Gaoshuang; Sheng, Wei; Zhang, Yan; Wang, Junping; Wu, Xuening; Wang, Shuo

    2016-05-18

    A novel fluorescence immunoassay for detecting sulfaquinoxaline (SQX) in animal-derived foods was developed using NaYF4:Yb/Tm upconversion nanoparticles (UCNPs) conjugated with antibodies as fluorescence signal probes, and monodisperse magnetic polystyrene microspheres (MMPMs) modified with coating antigen as immune-sensing capture probes for trapping and separating the signal probes. Based on a competitive immunoassay format, the detection limit of the proposed method for detecting SQX was 0.1 μg L(-1) in buffer and 0.5 μg kg(-1) in food samples. The recoveries of SQX in spiked samples ranged from 69.80 to 133.00%, with coefficients of variation of 0.24-25.06%. The extraction procedure was fast, simple, and environmentally friendly, requiring no organic solvents. In particular, milk samples can be analyzed directly after simple dilution. This method has appealing properties, such as sensitive fluorescence response, a simple and fast extraction procedure, and environmental friendliness, and could be applied to detecting SQX in animal-derived foods.

  7. Facile Method for Preparation of Silica Coated Monodisperse Superparamagnetic Microspheres

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    Xuan-Hung Pham

    2016-01-01

    Full Text Available This paper presents a facile method for preparation of silica coated monodisperse superparamagnetic microsphere. Herein, monodisperse porous polystyrene-divinylbenzene microbeads were prepared by seeded emulsion polymerization and subsequently sulfonated with acetic acid/H2SO4. The as-prepared sulfonated macroporous beads were magnetized in presence of Fe2+/Fe3+ under alkaline condition and were subjected to silica coating by sol-gel process, providing water compatibility, easily modifiable surface form, and chemical stability. FE-SEM, TEM, FT-IR, and TGA were employed to characterize the silica coated monodisperse magnetic beads (~7.5 μm. The proposed monodisperse magnetic beads can be used as mobile solid phase particles candidate for protein and DNA separation.

  8. Elongational viscosity of monodisperse and bidisperse polystyrene melts

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.; Hassager, Ole

    2006-01-01

    The start-up and steady uniaxial elongational viscosity have been measured for two monodisperse polystyrene melts with molecular weights of 52 and 103 kg/mole, and for three bidisperse polystyrene melts. The monodisperse melts show a maximum in the steady elongational viscosity vs. the elongation...

  9. Preparation and Characterization of Monodisperse Polystyrene Microspheres%单分散性聚苯乙烯微球的制备与表征

    Institute of Scientific and Technical Information of China (English)

    万纪强; 石志琪

    2012-01-01

    Appropriate amount of sodium styrene sulfonate is introduced into the system of styrene emulsion polymerization in copolymerization by using emulsifier-free emulsion polymerization. The polymerization process is divided into two stages, in the first stage the ratio of sodium styrene sulfonate and styrene is the key factor which determines latex diameter and the monodispersity. When the reaction achieves high conversion rate, the second stage's monomer mixture is added into the reactant. The ratio of the sodium styrene sulfonate and styrene in this stage determines the particle's final surface charge density. Through the above two stages by emulsifier-free emulsion polymerization, latex particle of particle size of 100~400nm, good monodispersity, high surface charge density with the core-shell structure is successfully prepared. On this foundation, the influence of the ratio of styrene and sodium styrene sulfonate in the first stage on latex particle diameter and the influence of latex particle diameter on the microsphere's surface charge density are discussed.%利用无皂乳液聚合[1,2],在苯乙烯的乳液聚合体系中引入适量的苯乙烯磺酸钠参与共聚合.聚合过程中分两阶段料,第一阶段中苯乙烯磺酸钠与苯乙烯的比例是决定乳胶粒粒径及单分散性的关键因素.当反应达到较高的转化率时,加入第二阶段单体混合物,此阶段中的苯乙烯磺酸钠与苯乙烯的比例决定了最终胶粒表面电荷密度.利用上述两阶段无皂乳液聚合法制备了粒径在100~400nm,单分散性较好,表面电荷密度较高并且具有核壳结构的乳胶粒.在此基础上,讨论了的第一阶段中苯乙烯和苯乙烯磺酸钠的比例对乳胶粒粒径的影响以及乳胶粒粒径对微球表面电荷密度的影响.

  10. Preparation of polystyrene microspheres for laser velocimetry in wind tunnels

    Science.gov (United States)

    Nichols, Cecil E., Jr.

    1987-01-01

    Laser Velocimetry (L/V) had made great strides in replacing intrusive devices for wind tunnel flow measurements. The weakness of the L/V has not been the L/V itself, but proper size seeding particles having known drag characteristics. For many Langley Wind Tunnel applications commercial polystyrene latex microspheres suspended in ethanol, injected through a fluid nozzle provides excellent seeding but was not used due to the high cost. This paper provides the instructions, procedures, and formulations for producing polystyrene latex monodisperse microspheres of 0.6, 1.0, 1.7, 2.0, and 2.7 micron diameters. These are presently being used at Langley Research Center as L/V seeding particles.

  11. Effect of Mixed Solvent on Fabrication, Morphology and Monodispersity of Microspheres with Hydrophobic Poly(butyl methacrylate) Shells

    Institute of Scientific and Technical Information of China (English)

    XIAO Xincai; LU Cheng

    2012-01-01

    Monodisperse microspheres (mean diameter 200-300 nm) with polystyrene cores and poly(acrylamide-co-buty1 methacrylate) shells were prepared by using a free radical polymerization method.Moreover,the effect of mixed solvent on the preparation,morphology and monodispersity was investigated.The experimental results showed that solubility parameter of butyl methacrylate and solvent affected mainly the molding of monodisperse core-shell microspheres.When the microspheres were fabricated in a sequential synthesis process,addition of hydrophilic and organic solvent including butyl methacrylate led to spherical degree of the particles becoming worse,and the mean diameter of the microspheres decreased and the monodispersity became better with increasing the crosslinker methylenebisacrylamide dosage.

  12. Preparation of monodisperse magnetic polymer microspheres by swelling and thermolysis technique.

    Science.gov (United States)

    Yang, Chengli; Shao, Qian; He, Jie; Jiang, Biwang

    2010-04-06

    A novel process for the preparation of monodisperse magnetic polymer microspheres by uniquely combining swelling and thermolysis technique was reported. The monodisperse polystyrene microspheres were first prepared by dispersion polymerization and swelled in chloroform. Then, ferric oleate was dispersed in chloroform as a precursor and impregnated into the swollen polymer microspheres. Subsequently, the iron oxide nanoparticles were formed within the polymer matrix by thermal decomposition of ferric oleate. The morphology, inner structure, and magnetic properties of the magnetic polymer microspheres were studied with a field emission scanning electron microscope (SEM), transmission electron microscope (TEM), and superconducting quantum interference device (SQUID) magnetometer. The results showed that the average diameter of the magnetic polymer microspheres was 5.1 microm with a standard deviation of 0.106, and the magnetic polymer microspheres with saturation magnetization of 12.6 emu/g exhibited distinct superparamagnetic characteristics at room temperature. More interestingly, the magnetite nanoparticles with a spinel structure are evenly distributed over the whole area of the polymer microspheres. These magnetic polymer microspheres have potential applications in biotechnology.

  13. Synthesis of raspberry-like magnetic polystyrene microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Xu Zhizhong [Key Laboratory of Molecular Engineering of Polymers (Ministry of Education), Department of Macromolecular Science, Fudan University, Shanghai 200433 (China); Xia Ao [Key Laboratory of Molecular Engineering of Polymers (Ministry of Education), Department of Macromolecular Science, Fudan University, Shanghai 200433 (China); Wang Changchun [Key Laboratory of Molecular Engineering of Polymers (Ministry of Education), Department of Macromolecular Science, Fudan University, Shanghai 200433 (China)]. E-mail: ccwang@fudan.edu.cn; Yang Wuli [Key Laboratory of Molecular Engineering of Polymers (Ministry of Education), Department of Macromolecular Science, Fudan University, Shanghai 200433 (China); Fu Shoukuang [Key Laboratory of Molecular Engineering of Polymers (Ministry of Education), Department of Macromolecular Science, Fudan University, Shanghai 200433 (China)

    2007-06-15

    Raspberry-like magnetic polystyrene microspheres were prepared via soap-free emulsion polymerization using 2,2'-azobis(2-methylpropionamidine) dihydrochloride (V50) as initiator. The effect of polymerization parameters, such as initiator type, initiator content and the feeding sequence on the particle size and morphology of magnetic polystyrene microspheres, were examined. The final magnetic polystyrene microspheres were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA). The experimental results showed that V50 was a suitable initiator for preparation of raspberry-like magnetic polystyrene microspheres.

  14. STUDY ON SYNTHESIS OF SELF CORSS LINKED POLYSTYRENE LATEX MICROSPHERES

    Institute of Scientific and Technical Information of China (English)

    DaiLizong; ZouYousi; 等

    1997-01-01

    Emulsifier-free emulsion polymerization of styrene in the presence of β-hydroxy propyl acrylate was studied.The emulsifier-free self cross linked polystyrene latex microspheres was obtained.Monomer conversion is higher than 90% when [St],[β-HPA],[KPS] is 2.66,0.228,and 5.8×10-3mol/L respectively under 80℃ for 5h.The mono-dispersed latex particle diameter and colloidal particle concentration were given as D=0.23um,N=3.13×1013/cm3 by TEM analyse,The factors of influencing latex stability were discussed.Thecopolymer was characterized by IR and dissolution experiment.The apparent activation energy of polymerization and polymerization rate constant were obtained to be 78.7KJ/mol and 514.4/mol.s respectively.

  15. Preparation and characterization of monodispersed PS/Ag composite microspheres through modified electroless plating

    Energy Technology Data Exchange (ETDEWEB)

    Ma Yuehui [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Zhang Qinghua, E-mail: qhzhang@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China)

    2012-07-15

    A modified electroless silver-plating process has been devised for the preparation of monodispersed, polystyrene/silver (PS/Ag) composite microspheres with tunable shell thickness. Tailoring was achieved by altering the concentration of the silver precursor in the plating bath. PS/Ag composite microspheres were characterized by field-emission scanning electron microscopy, ultraviolet-visible absorption, X-ray diffraction and thermogravimetric analysis. The results showed that a dense, stable and uniform silver nanoshell was formed on the surface of PS microspheres in the presence of poly(vinylpyrrolidone) and glucose. The bulk conductivity of the PS/Ag composites increased from 1.16 S/m to 3.57 Multiplication-Sign 10{sup 4} S/m, corresponding to a shell thickness of 35-198 nm. The PS/Ag composite microspheres with diameters of ca. 3 {mu}m might have great potential to be used as fillers in anisotropic conductive films because of the uniform diameter, low density and good conductivity of the microspheres.

  16. MONODISPERSED AND NANOSIZED DENDRIMER/POLYSTYRENE LATEX PARTICLES

    Institute of Scientific and Technical Information of China (English)

    Changfeng Yi; Zushun Xu; Warren T. Ford

    2004-01-01

    Emulsion polymerization of styrene was carried out using dendrimer DAB-dendr-(NH2)64 as seed. The size and size distribution of the emulsion particles were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS), and the effects of emulsion polymerization conditions on the preparation of emulsion particle were investigated. It has been found that the nanosized dendrimer/polystyrene polymer emulsion particles obtained were in the range of 26~64 nm in diameter, and were monodisperse; the size and size distribution of emulsion particles were influenced by the contents of dendrimer DAB-dendr-(NH2)64, emulsifier and initiator, as well as the pH value.

  17. A novel method for preparing monodispersed polystyrene nanoparticles

    Institute of Scientific and Technical Information of China (English)

    LIU Kaiyi; WANG Zhaoqun

    2007-01-01

    A preparation manner for monodispersed polystyrene(PS)nanoparticles polymerized by using a novel addition procedure of a monomer is suggested.In systems containing a smaller amount of surfactant compared with conventional microemulsion polymerization,the polymerization processes consists of three stages:adding dropwise the first part of the monomer for a few minutes at 80℃ and polymerizing for 1 h;adding collectively the residual part of the monomer and polymerizing at the same temperature for another 1 h;and then polymerizing at 85℃ for another 1 h.Based on discussions on the nucleation mechanism of particles in the polymerization system,the influences of monomer weight added dropwise,and amounts of initiator and emulsifier on the size and distribution of PS particles were investigated.PS nanoparticles with smaller diameter such as a number-average diameter of 18.7 nm and better monodispersity were obtained since the dropped styrene amount was suitable under 20wt-% emulsifier amount and 3wt-% initiator amount based on the monomer.

  18. Biotemplate synthesis of monodispersed iron phosphate hollow microspheres.

    Science.gov (United States)

    Cao, Feng; Li, Dongxu

    2010-03-01

    Monodispersed iron phosphate hollow microspheres with a high degree of crystallization were prepared through a facile in situ deposition method using rape pollen grains as a biotemplate. The functional group on the surface of the pollen grains could adsorb Fe(3+), which provided the nucleation sites for growth of iron phosphate nanoparticles. After being sintered at 600 degrees C for 10 h, the pollen grains were removed and iron phosphate hollow microspheres were obtained. A scanning electron microscope and x-ray diffraction were applied to characterize the morphology and crystalline structure of the pollen grains, iron phosphate-coated pollen grains and iron phosphate hollow microspheres. Differential scanning calorimetry and thermogravity analyses were performed to investigate the thermal behavior of the iron phosphate-coated pollen grains during the calcinations. Energy dispersive spectroscopy and Fourier transform infrared spectroscopy were utilized to investigate the interaction between the pollen grains and iron phosphate. The effect of the pollen wall on the surface morphology of these iron phosphate hollow microspheres was also proven in this work.

  19. Biotemplate synthesis of monodispersed iron phosphate hollow microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Cao Feng; Li Dongxu, E-mail: dongxuli@njut.edu.c [College of Materials Science and Engineering, Nanjing University of Technology, Jiangsu Nanjing 210009 (China)

    2010-03-15

    Monodispersed iron phosphate hollow microspheres with a high degree of crystallization were prepared through a facile in situ deposition method using rape pollen grains as a biotemplate. The functional group on the surface of the pollen grains could adsorb Fe{sup 3+}, which provided the nucleation sites for growth of iron phosphate nanoparticles. After being sintered at 600 deg. C for 10 h, the pollen grains were removed and iron phosphate hollow microspheres were obtained. A scanning electron microscope and x-ray diffraction were applied to characterize the morphology and crystalline structure of the pollen grains, iron phosphate-coated pollen grains and iron phosphate hollow microspheres. Differential scanning calorimetry and thermogravity analyses were performed to investigate the thermal behavior of the iron phosphate-coated pollen grains during the calcinations. Energy dispersive spectroscopy and Fourier transform infrared spectroscopy were utilized to investigate the interaction between the pollen grains and iron phosphate. The effect of the pollen wall on the surface morphology of these iron phosphate hollow microspheres was also proven in this work.

  20. Microwire formation based on dielectrophoresis of electroless gold plated polystyrene microspheres

    Institute of Scientific and Technical Information of China (English)

    Jiang Hong-Yuan; Ren Yu-Kun; Tao Ye

    2011-01-01

    Microspheres coated with a perfectly conductive surface have many advantages in the applications of biosensors and micro-electromechanical systems. Polystyrene microspheres with the diameter of 10 μm were coated with a 50 nmthick gold layer using an electroless gold plating approach. Dielectrophoresis (DEP) for bare microspheres and shelled microspheres was theoretically analysed and the real part of the Clausius-Mossotti factor was calculated for the two kinds of microspheres. The experiments on the dielectrophoretic characterisation of the uncoated polystyrene microspheres and gold coated polystyrene microspheres (GCPMs) were carried out. Experimental results showed that the gold coated polystyrene microspheres were only acted by a positive dielectrophoretic force when the frequency was below 40M Hz,while the uncoated polystyrene microspheres were governed by a negative dielectrophoretic force in this frequency range.The gold coated polystyrene microspheres were exploited to form the microwire automatically according to their stable dielectrophoretic and electric characterisations.

  1. Measurements of extrinsic fluorescence in Intralipid and polystyrene microspheres

    Science.gov (United States)

    Du Le, Vinh Nguyen; Nie, Zhaojun; Hayward, Joseph E.; Farrell, Thomas J.; Fang, Qiyin

    2014-01-01

    The fluorescence of Intralipid and polystyrene microspheres with sphere diameter of 1 µm at a representative lipid and microsphere concentration for simulation of mucosal tissue scattering has not been a subject of extensive experimental study. In order to elucidate the quantitative relationship between lipid and microsphere concentration and the respective fluorescent intensity, the extrinsic fluorescence spectra between 360 nm and 650 nm (step size of 5 nm) were measured at different lipid concentrations (from 0.25% to 5%) and different microsphere concentrations (0.00364, 0.0073, 0.0131 spheres per cubic micrometer) using laser excitation at 355 nm with pulse energy of 2.8 µJ. Current findings indicated that Intralipid has a broadband emission between 360 and 650 nm with a primary peak at 500 nm and a secondary peak at 450 nm while polystyrene microspheres have a single peak at 500 nm. In addition, for similar scattering properties the fluorescence of Intralipid solutions is approximately three-fold stronger than that of the microsphere solutions. Furthermore, Intralipid phantoms with lipid concentrations ~2% (simulating the bottom layer of mucosa) produce up to seven times stronger fluorescent emission than phantoms with lipid concentration ~0.25% (simulating the top layer of mucosa). The fluoresence decays of Intralipid and microsphere solutions were also recorded for estimation of fluorescence lifetime. PMID:25136497

  2. Silica Microspheres Are Superior to Polystyrene for Microvesicle Analysis by Flow Cytometry

    Science.gov (United States)

    2015-02-16

    Regular Article Silica microspheres are superior to polystyrene for microvesicle analysis by flow cytometry☆ Bijaya Kumar Parida ⁎, Hiram Garrastazu...February 2015 Available online 16 February 2015 Keywords: Microvesicles Cell-derived microparticles Silica microspheres Polystyrene microspheres ...is used to characterize MVs. Polystyrene microspheres are often used in flow cytometry to distinguish MV from cells by setting a 1-μm MV gate in a

  3. Inherently fluorescent polystyrene microspheres for coating, sensing and cellular imaging.

    Science.gov (United States)

    Qu, Jian-Bo; Xu, Yu-Liang; Liu, Yu; Wang, Yanan; Sui, Yuanhong; Liu, Jian-Guo; Wang, Xiaojuan

    2017-04-01

    Commercially available polystyrene (PS) fluorescent microspheres are widely used in biological field for tracing, in vivo imaging and calibration of flow cytometry, among other applications. However, these particles do suffer from some drawbacks such as the leakage and photobleaching of organic dyes within them. In the present study, inherently fluorescent properties of PS based microspheres have been explored for the first time. Here we find that a simple chloromethylation reaction endows the polystyrene particles with inherent fluorescence without any subsequent conjugation of an external fluorophore. A possible mechanism for fluorescence is elucidated by synthesizing and investigating p-ethylbenzyl chloride, a compound with similar structure. Significantly, no photobleaching or leaking issues were observed owing to the stable structure of the microspheres. Chloromethylated PS (CMPS) microspheres can keep their perpetual blue fluorescence even in dry powder state making them attractive as a potential coating material. Furthermore, the chloromethyl groups on CMPS microspheres make them very convenient for further functionalization. Poly(ethylene glycol) (PEG) grafted microspheres showed good biocompatibility and negligible cytotoxicity, and could be used to image intracellular Fe(3+) due to the selective fluorescence quenching effect of aqueous Fe(3+) in cytoplasm.

  4. PREPARATION OF MONODISPERSE CROSSLINKED POLYMER MICROSPHERES HAVING CHLOROMETHYL GROUP BY DISTILLATION-PRECIPITATION POLYMERIZATION

    Institute of Scientific and Technical Information of China (English)

    Shu-Feng Li; Xin-Lin Yang; Wen-Qiang Huang

    2005-01-01

    Monodisperse crosslinked poly(chloromethylstyrene-co-divinylbenzene) (poly(CMSt-co-DVB)) microspheres were prepared by distillation-precipitation copolymerization of chloromethylstyrene (CMSt) and divinylbenzene (DVB) in neat acetonitrile. The polymer particles had clean surfaces due to the absence of any added stabilizer. The size of the particles ranges from 2.59 μm to 3.19 μm and with mono-dispersity around 1.002-1.014. The effects of monomer feed in copolymerization on the microsphere formation were described. The polymer microspheres were characterized by SEM and chlorinity elemental analysis.

  5. Study of electrodepositing Au on hollow polystyrene microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Jin Rong [Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box 919-987, Mianyang 621900 (China); School of Material Science and Engineering, Xihua University, Chengdu 610039 (China); Zhang Yunwang [Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box 919-987, Mianyang 621900 (China); Zhang Lin, E-mail: zhlmy@sina.com [Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box 919-987, Mianyang 621900 (China); Wei Chengfu, E-mail: wcf@mail.xhu.edu.cn [School of Material Science and Engineering, Xihua University, Chengdu 610039 (China); Guo Jianjun [School of Material Science and Engineering, Xihua University, Chengdu 610039 (China)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer The gold is electrodeposited on hollow polystyrene microspheres by self-designed setup in this paper. Black-Right-Pointing-Pointer The Au electrodeposit is finer and more uniform on account of the microspheres freely move on the cathode. Black-Right-Pointing-Pointer The morphology, thickness and roughness of Au electrodeposits were analyzed using Scanning Electron Microscopy, X-ray diffraction and Atomic Force Microscope, respectively. - Abstract: The electrodeposited Au film on hollow polystyrene microspheres is successfully prepared by a set of self-designed device. The film is more compact and uniform on account of the microspheres freely moving on the cathode. These experiments mainly focus on the analysis of spherical symmetry, thickness and roughness of electrodeposited Au film. Under conditions of current density 1.5-3 mA cm{sup -2}, the temperature 25 Degree-Sign C, and the stirring rate 150 rpm, the electrodeposited microsphere is coated with a considerably orbicular film. The morphology, thickness and roughness of Au electrodeposits are studied by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Atomic Force Microscope (AFM), respectively.

  6. Preparation of monodisperse, superparamagnetic, luminescent, and multifunctional PGMA microspheres with amino-groups

    Institute of Scientific and Technical Information of China (English)

    WANG WeiCai; ZHANG Qi; ZHANG BingBo; LI DeNa; DONG XiaoQing; ZHANG Lei; CHANG Jin

    2008-01-01

    Micron-sized, monodisperse, superparamagnetic, luminescent composite poly(glycidyl methacrylate) (PGMA) microspheres with functional amino-groups were successfully synthesized in this study. The process of preparation was as follows: preparation of monodisperse poly(glycidyl methacrylate) mi-crospheres by dispersion polymerization method; modification of poly(glycidyl methacrylate) micro-spheres with ethylene diamine to form amino-groups; impregnation of iron ions (Fe2+ and Fe3+) inside the microspheres and subsequently precipitating them with ammonium hydroxide to form magnetite (Fe3O,4>) nanoparticles within the polymer microspheres; infusion of CdSe/CdS core-shell quantum dots (QDs) into magnetic polymer microspheres. Scanning electron microscopy (SEM) was used to char-acterize surface morphology and size distribution of composite microspheres. The average size of mi-crospheres was 1.42μm with a size variation of 3.8%, The composite microspheres were bright enough and easily observed using a conventional fluorescence microscope, The composite microspheres were easily separated from solution by magnetic decantation using a permanent magnet. The new multi-functional composite microspheres are promising to be used in a variety of bioanalytical assays in-volving luminescence detection and magnetic separation.

  7. Post-facelift flap necrosis treatment using charged polystyrene microspheres

    Science.gov (United States)

    Weissman, Oren; Farber, Nimrod; Remer, Eric; Tessone, Ariel; Trivizki, Omer; Bank, Jonathan; Winkler, Eyal; Zilinsky, Isaac; Haik, Josef

    2013-01-01

    BACKGROUND: Flap necrosis following facial rhytidectomy constitutes a vexing and grievous complication to the patient and the surgeon. Treatment modalities that can expedite wound healing and re-epithelialization rates are highly desired. OBJECTIVES: To assess wound healing and re-epithelialization rates of open wounds following postrhytidectomy flap necrosis treated with commercially available charged polystyrene microspheres (Polyheal-1, Polyheal Ltd, Israel). METHODS: Flap necrosis following rhytidectomy with open wounds in three female patients were treated using dressings soaked with Polyheal-1. Wound closure rates were documented. RESULTS: The wounds demonstrated both accelerated granulation tissue formation and rapid re-epithelialization rates. No complications or side effects were encountered. CONCLUSIONS: Charged polystyrene microspheres may offer a new and efficacious way to treat open wounds due to flap necrosis following facial rhytidectomy. Further research with larger patient numbers is still needed to verify these findings. PMID:24431937

  8. Elongational viscosity of monodisperse and bidisperse polystyrene melts

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik Koblitz; Hassager, Ole

    2005-01-01

    polystyrene melt with a molecular weight of 390 kg/mole (PS390K). The measurements have all been preformed on a Filament Streching Rheometer (FSR) equipped with an oven: A cylindrical test sample is placed between two parallel, circular plates and stretched. A load cell measures the transmitted force...

  9. Elongational viscosity of monodisperse and bidisperse polystyrene melts

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik Koblitz; Hassager, Ole

    2005-01-01

    polystyrene melt with a molecular weight of 390 kg/mole (PS390K). The measurements have all been preformed on a Filament Streching Rheometer (FSR) equipped with an oven: A cylindrical test sample is placed between two parallel, circular plates and stretched. A load cell measures the transmitted force...

  10. Preparation and characterization of monodisperse large-porous silica microspheres as the matrix for protein separation.

    Science.gov (United States)

    Xia, Hongjun; Wan, Guangping; Zhao, Junlong; Liu, Jiawei; Bai, Quan

    2016-11-04

    High performance liquid chromatography (HPLC) is a kind of efficient separation technology and has been used widely in many fields. Micro-sized porous silica microspheres as the most popular matrix have been used for fast separation and analysis in HPLC. In this paper, the monodisperse large-porous silica microspheres with controllable size and structure were successfully synthesized with polymer microspheres as the templates and characterized. First, the poly(glycidyl methacrylate-co-ethyleneglycol dimethacrylate) microspheres (PGMA-EDMA) were functionalized with tetraethylenepentamine (TEPA) to generate amino groups which act as a catalyst in hydrolysis of tetraethyl orthosilicate (TEOS) to form Si-containing low molecular weight species. Then the low molecular weight species diffused into the functionalized PGMA-EDMA microspheres by induction force of the amino groups to form polymer/silica hybrid microspheres. Finally, the organic polymer templates were removed by calcination, and the large-porous silica microspheres were obtained. The compositions, morphology, size distribution, specific surface area and pore size distribution of the porous silica microspheres were characterized by infrared analyzer, scanning-electron microscopy, dynamic laser scattering, the mercury intrusion method and thermal gravimetric analysis, respectively. The results show that the agglomeration of the hybrid microspheres can be overcome when the templates were functionalized with TEPA as amination reagent, and the yield of 95.7% of the monodisperse large-porous silica microspheres can be achieved with high concentration of polymer templates. The resulting large-porous silica microspheres were modified with octadecyltrichlorosilane (ODS) and the chromatographic evaluation was performed by separating the proteins and the digest of BSA. The baseline separation of seven kinds of protein standards was achieved, and the column delivered a better performance when separating BSA digests

  11. Studies on Monodispersed Microspheres of Zinc Sulfide Doped with Mn2+

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, zinc acetate, manganese acetate and thiacetamide are used as raw materials to successfully synthesize monodispersed ZnS:Mn2+ microspheres by using hydrothermal method and taking P123 surfactant as a template. The products were characterized by XRD, STEM,FT-IR and N2 adsorption-desorption. And the results show that the diameter of this microsphere is 1.0 μm or so, which is larger than that of ZnS microsphere without Mn2+ doping, and it has monodispersion, smooth surface and uniform size. The doping of Mn2+ does not obviously change the structure of monodispersed ZnS microsphere. The photoluminescence peak lies in a wide band ranging from 450 to 650 nm, and the microspheres emit orange light;with the increase of Mn2+concentration, fluorescence intensity of ZnS:Mn2+ microsphere changes, and when the mole ratio of Mn2+:Zn2+is 0.3:1, the fluorescence intensity is the strongest.

  12. On-demand one-step synthesis of monodisperse functional polymeric microspheres with droplet microfluidics.

    Science.gov (United States)

    Yu, Xu; Cheng, Gong; Zhou, Ming-Da; Zheng, Si-Yang

    2015-04-07

    A simple and robust method for one-step synthesis of monodisperse functional polymeric microspheres was established by generation of reversed microemulsion droplets in aqueous phase inside microfluidic chips and controlled evaporation of the organic solvent. Using this method, water-soluble nanomaterials can be easily encapsulated into biodegradable Poly(D,L-lactic-co-glycolic acid) (PLGA) to form functional microspheres. By controlling the flow rate of microemulsion phase, PLGA polymeric microspheres with narrow size distribution and diameters in the range of ∼50-100 μm were obtained. As a demonstration of the versatility of the approach, high-quality fluorescent CdTe:Zn(2+) quantum dots (QDs) of various emission spectra, superparamagnetic Fe3O4 nanoparticles, and water-soluble carbon nanotubes (CNTs) were used to synthesize fluorescent PLGA@QDs, magnetic PLGA@Fe3O4, and PLGA@CNTs polymeric microspheres, respectively. In order to show specific applications, the PLGA@Fe3O4 were modified with polydopamine (PDA), and then the silver nanoparticles grew on the surfaces of the PLGA@Fe3O4@PDA polymeric microspheres by reducting the Ag(+) to Ag(0). The as-prepared PLGA@Fe3O4@PDA-Ag microspheres showed a highly efficient catalytic reduction of the 4-nitrophenol, a highly toxic substance. The monodisperse uniform functional PLGA polymeric microspheres can potentially be critically important for multiple biomedical applications.

  13. Mechanism of immunoglobulin G adsorption on polystyrene microspheres.

    Science.gov (United States)

    Sofińska, Kamila; Adamczyk, Zbigniew; Barbasz, Jakub

    2016-01-01

    The adsorption of polyclonal immunoglobulin G (IgG) on negatively charged polystyrene microparticle suspension (latex) was studied by using the Laser Doppler Velocimetry (LDV) measurements. Using this technique, the dependence of the electrophoretic mobility of particles on the IgG concentration in the suspension was measured for various ionic strengths and pH 3.5. The increase in the electrophoretic mobility was quantitatively interpreted in terms of the 3D electrokinetic model. On the other hand, the maximum coverage of IgG on latex was determined using the depletion method based on AFM imaging. It was shown that IgG adsorption was irreversible and that its maximum coverage on the microspheres increased from 1.4mgm(-2) for 0.001M NaCl to 2.0mgm(-2) for 0.15M NaCl. This was interpreted in terms of reduced electrostatic repulsion among adsorbed molecules. The stability of IgG monolayers on the particles was confirmed in separate experiments where changes in its electrophoretic mobility were monitored over prolonged time periods. Additionally, the acid-base properties of the IgG monolayers on latex were determined in pH cycling experiments. The isoelectric point of the IgG monolayers on the microspheres was 4.8. The results obtained in this work indicate that basic physicochemical characteristics of IgG can be acquired via electrophoretic mobility measurements using microgram quantities of the protein.

  14. Synthesis of 3-D ordered macroporous silicate using the template formed from monodispersed polystyrene latex

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on the template formed from monodispersed polystyrene (PS) latex, a modified fast sol-gel process was employed to synthesize a three-dimensional ( 3-D ) ordered macroporous silica material after removing the template by calcination at high temperature. It was indicated that there existed highly ordered packed pores within the whole silica material by SEM morphology observation. It was also found that the pores were interconnected. The pore size could be controlled mainly by varying the particle size of the latex ranging from 101 to 102 nm. The formation process of the ordered pores was also preliminarily discussed.

  15. Synthesis and characterization of monodispersed inorganic/organic core/shell microspheres with fluorescence

    Institute of Scientific and Technical Information of China (English)

    ZHANG Kai; HAN Kun; ZHANG Xuehai; YANG Bai

    2005-01-01

    @@ In recent years, the semiconductor nanocrystals (NCs) have attracted great interest due to their potentials in photonics, electronics, magnetics and catalysis, and the monodispersed organic or inorganic microspheres doped NCs display predominant characteristics in the fabrication and study for photonic crystals[1,2], and considerable effort has been devoted to the design and synthesis of CdTe NCs doped colloid with well fluorescence[3-8]. For example, CdTe NCs were fabricated on the surfaces of silica or polymer microspheres by the methods of layer-by-layer assembly, and CdTe NCs were also doped into inorganic or organic microspheres through sol-gel process or swell- ing.

  16. Polystyrene-ZnO core-shell microspheres and hollow ZnO structures synthesized with the sulfonated polystyrene templates

    Science.gov (United States)

    Yang, Yang; Chu, Ying; Zhang, Yanping; Yang, Fuyong; Liu, Jinglin

    2006-02-01

    Mono-sized sulfonated polystyrene (PS) microspheres were used as templates to prepare PS-zinc oxide (ZnO) core-shell microspheres. Two different hollow ZnO structures were obtained after removing the PS cores by solvent extraction or calcinations. However, we obtained rod-like ZnO by either using unsulfonated PS microspheres as templates or without any templates. Transmission electron microscope (TEM) and scanning electron microscope (SEM) images were used to characterize the structures and morphologies of all the samples. X-ray diffraction (XRD), electron diffraction (ED) and infrared (IR) spectra were, respectively, used to study the crystal structure and composition of samples, respectively.

  17. Preparation of monodisperse aqueous microspheres containing high concentration of l-ascorbic acid by microchannel emulsification.

    Science.gov (United States)

    Khalid, Nauman; Kobayashi, Isao; Neves, Marcos A; Uemura, Kunihiko; Nakajima, Mitsutoshi; Nabetani, Hiroshi

    2015-01-01

    Monodisperse aqueous microspheres containing high concentrations of l-ascorbic acid with different concentrations of sodium alginate (Na-ALG) and magnesium sulfate (MgSO4) were prepared by using microchannel emulsification (MCE). The continuous phase was water-saturated decane containing a 5% (w/w) hydrophobic emulsifier. The flow rate of the continuous phase was maintained at 10 mL h(-1), whereas the pressure applied to the disperse phase was varied between 3 and 25 kPa. The disperse phase optimized for successfully generating aqueous microspheres included 2% (w/w) Na-ALG and 1% (w/w) MgSO4. At a higher MgSO4 concentration, the generated microspheres resulted in coalescence and subsequent bursting. At a lower MgSO4 concentration, unstable and polydisperse microspheres were obtained. The aqueous microspheres generated from the MCs under optimized conditions had a mean particle diameter (dav) of 14-16 µm and a coefficient of variation (CV) of less than 8% at the disperse phase pressures of 5-15 kPa.

  18. Characterization of Fluorescent Polystyrene Microspheres for Advanced Flow Diagnostics

    Science.gov (United States)

    Maisto, Pietro M. F.; Lowe, K. Todd; Byun, Guibo; Simpson, Roger; Vercamp, Max; Danley, Jason E.; Koh, Brian; Tiemsin, Pacita; Danehy, Paul M.; Wohl, Christopher J.

    2013-01-01

    Fluorescent dye-doped polystyrene latex microspheres (PSLs) are being developed for velocimetry and scalar measurements in variable property flows. Two organic dyes, Rhodamine B (RhB) and dichlorofluorescence (DCF), are examined to assess laser-induced fluorescence (LIF) properties for flow imaging applications and single-shot temperature measurements. A major interest in the current research is the application of safe dyes, thus DCF is of particular interest, while RhB is used as a benchmark. Success is demonstrated for single-point laser Doppler velocimetry (LDV) and also imaging fluorescence, excited via a continuous wave 2 W laser beam, for exposures down to 10 ms. In contrast, when exciting with a pulsed Nd:YAG laser at 200 mJ/pulse, no fluorescence was detected, even when integrating tens of pulses. We show that this is due to saturation of the LIF signal at relatively low excitation intensities, 4-5 orders of magnitude lower than the pulsed laser intensity. A two-band LIF technique is applied in a heated jet, indicating that the technique effectively removes interfering inputs such as particle diameter variation. Temperature measurement uncertainties are estimated based upon the variance measured for the two-band LIF intensity ratio and the achievable dye temperature sensitivity, indicating that particles developed to date may provide about +/-12.5 C precision, while future improvements in dye temperature sensitivity and signal quality may enable single-shot temperature measurements with sub-degree precision.

  19. Polystyrene microsphere-based lanthanide luminescent chemosensor for detection of organophosphate pesticides

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hongxing; HUA Xiufu; TUO Xinlin; CHEN Chuanzhi; WANG Xiaogong

    2012-01-01

    Fluorescent microspheres of polystyrene-based Eu(Ⅲ) complexes were prepared from TentaGel resin,2,6-bisbenzimidazolylpyridine and europium nitrate.The microspheres were characterized by FTIR spectroscopy,elemental analysis,XPS measurements and fluorescence spectroscopy.Characteristic red emission under irradiation of 365 nm light from a hand-held UV lamp was observed for the microspheres either in a solution or solid-state.Fluorescent quenching was observed when the microspheres were exposed to a trace amount of diethyl chlorophosphate (DCP) in the dispersion.The material and property can be potentially used to fabricate chemosensor in the detection of organophosphates.

  20. Dynamics of polyelectrolyte adsorption and colloidal flocculation upon mixing studied using mono-dispersed polystyrene latex particles

    NARCIS (Netherlands)

    Feng, Lili; Cohen Stuart, Martien; Adachi, Yasuhisa

    2015-01-01

    The dynamic behavior of polyelectrolytes just after their encounter with the surface of bare colloidal particles is analyzed, using the flocculation properties of mono-dispersed polystyrene latex (PSL) particles. Applying a Standardized Colloid Mixing (SCM) approach, effects of ionic strength and

  1. Monodisperse lignin fractions as standards in size-exclusion analysis: comparison with polystyrene standards.

    Science.gov (United States)

    Botaro, Vagner Roberto; Curvelo, Antonio Aprígio da Silva

    2009-05-01

    The difficulty of preparing monodisperse lignin fractions on a large scale is a limiting factor in many applications. The present paper addresses this problem by examining the properties and size-exclusion behavior of lignin isolated by the acetosolv pulping process from post-extraction crushed sugarcane bagasse. The isolated lignin was subjected to a solvent pretreatment, followed by preparative gel permeation chromatography fractionation. The fractions were analyzed by high-performance size-exclusion chromatography (HPSEC) and these samples showed a great decrease in polydispersity, compared to the original acetosolv lignin. Several fractions of very low polydispersity, close to unity, were employed as calibration curve standards in HPSEC analysis. This original analytical approach allowed calibration with these lignin fractions to be compared with the polystyrene standards that are universally employed for lignin molecular mass determination. This led to a noteworthy result, namely that the lignin fractions and polystyrene standards showed very similar behavior over a large range of molecular masses in a typical HPSEC analysis of acetosolv lignin.

  2. Preparation and Characterization of Gd3+-doped Monodisperse TiO2 Hollow Microsphere

    Institute of Scientific and Technical Information of China (English)

    JI; Feng; SHANG; Pengbo; ZHENG; Yuying

    2015-01-01

    Gd3+-doped monodisperse TiO2 hollow microspheres with various molar ratios of Gd3+/TBOT were synthesized via a novel process, which involved the preparation of SiO2 templates, deposition of Gd3+-doped TiO2 by sol-gel, SiO2 coating, heat treatment to induce crystallization of TiO2, and finally etching away the inner SiO2 templates and outer SiO2 layers. The synthesized samples were characterized by transmission electron microscopy(TEM), scanning electron microscopy(SEM), X-ray diffraction(XRD), diffuse reflection spectroscopy(DRS), specific surface area measurement(BET) and X-ray photoelectron spectroscopy(XPS), respectively. The photocatalytic activity of Gd3+-doped samples was evaluated via photocatalytic degradation of Methyl orange under UV irradiation. The results show that the SiO2 layers prevent aggregation of TiO2 hollow microspheresand improve the thermal stability of the synthesized samples. Also, the photocatalytic activity of monodisperse TiO2 hollow microspheres can be enhanced at the optimal molar ration of Gd3+/TBOT of 0.7%.

  3. Uptake, accumulation and elimination of polystyrene microspheres in tadpoles of Xenopus tropicalis.

    Science.gov (United States)

    Hu, Lingling; Su, Lei; Xue, Yingang; Mu, Jingli; Zhu, Jingmin; Xu, Jiang; Shi, Huahong

    2016-12-01

    Microplastic is an emerging contaminant affecting freshwater and marine ecosystem across the globe. In the present study, the filter feeding tadpoles of Xenopus tropicalis were exposed to polystyrene microspheres (1 and 10 μm) for 48 h. Microspheres were observed in gills and digestive tract of tadpoles within 1 h after exposure as well as in feces 6 h after exposure. The accumulation of microspheres in the tadpoles were concentration dependent (Univariate ANOVA, p  0.05). After the exposed tadpoles were transferred to clean water, the number of microspheres in the tadpoles decreased dramatically after 1 d and continued to decrease gradually afterwards. The absorbed polystyrene particles in unfed tadpoles was significantly higher than those in the fed tadpoles at 12 and 24 h after exposure. After transfer to clean water, the fed tadpoles showed a significant decrease in the amount of absorbed polystyrene particles, while the unfed tadpoles showed no significant change in the amount of absorbed polystyrene particles. Our results suggested that microspheres were likely to be ingested and egested relatively fast by tadpoles. Our results indicated that aquatic vertebrate organisms might ingest more microplastics if the abundance of microplastics continues to increase while the available food becomes less.

  4. Templated synthesis of monodisperse mesoporous maghemite/silica microspheres for magnetic separation of genomic DNA

    Science.gov (United States)

    Chen, Feng; Shi, Ruobing; Xue, Yun; Chen, Lei; Wan, Qian-Hong

    2010-08-01

    A novel method is described for the preparation of superparamagnetic mesoporous maghemite (γ-Fe 2O 3)/silica (SiO 2) composite microspheres to allow rapid magnetic separation of DNA from biological samples. With magnetite (Fe 3O 4) and silica nanoparticles as starting materials, such microspheres were synthesized by the following two consecutive steps: (1) formation of monodispersed organic/inorganic hybrid microspheres through urea-formaldedyde (UF) polymerization and (2) removal of the organic template and phase transformation of Fe 3O 4 to γ-Fe 2O 3 by calcination at elevated temperatures. The as-synthesized particles obtained by heating at temperature 300 °C feature spherical shape and uniform particle size ( dparticle=1.72 μm), high saturation magnetization ( Ms=17.22 emu/g), superparamagnetism ( Mr/ Ms=0.023), high surface area ( SBET=240 m 2/g), and mesoporosity ( dpore=6.62 nm). The composite microsphere consists of interlocked amorphous SiO 2 nanoparticles, in which cubic γ-Fe 2O 3 nanocrystals are homogeneously dispersed and thermally stable against γ- to α-phase transformation at temperatures up to 600 °C. With the exposed iron oxide nanoparticles coated with a thin layer of silica shell, the magnetic microspheres were used as a solid-phase adsorbent for rapid extraction of genomic DNA from plant samples. The results show that the DNA templates isolated from pea and green pepper displayed single bands with molecular weights greater than 8 kb and A260/ A280 values of 1.60-1.72. The PCR amplification of a fragment encoding the endogenous chloroplast ndhB gene confirmed that the DNA templates obtained were inhibitor-free and amenable to sensitive amplification-based DNA technologies.

  5. Polystyrene Microspheres Coated with Smooth Polyaniline Shells:Preparation and Characterization

    Institute of Scientific and Technical Information of China (English)

    YUAN Yi; LIAN Yanqing

    2009-01-01

    Polystyrene/polyaniline core-shell structure microspheres were synthesized in the presence of poly(sodium 4-styrenesulfonate) as stabilizer and hydrochloric acid as dopant to improve the processibility of conducting polyaniline. After the one-pot reacting process, the product was easily purified by washing with water. The polyaniline shell covering the polystyrene sphere surface was confirmed with FT-IR and X-ray photoelectron spectroscopy. The conductivity of the polyaniline-coated polystyrene particles was 0.0017 S/cm and increased to 0.1 S/cm after being doped in the HCI vapor. The morphology of the microspheres was characterized by TEM and SEM. The particles show a more uniform and smooth surface than previous particles.

  6. Templated synthesis of monodisperse mesoporous maghemite/silica microspheres for magnetic separation of genomic DNA

    Energy Technology Data Exchange (ETDEWEB)

    Chen Feng; Shi Ruobing; Xue Yun; Chen Lei [School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072 (China); Wan Qianhong, E-mail: qhwan@tju.edu.c [School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072 (China)

    2010-08-15

    A novel method is described for the preparation of superparamagnetic mesoporous maghemite (gamma-Fe{sub 2}O{sub 3})/silica (SiO{sub 2}) composite microspheres to allow rapid magnetic separation of DNA from biological samples. With magnetite (Fe{sub 3}O{sub 4}) and silica nanoparticles as starting materials, such microspheres were synthesized by the following two consecutive steps: (1) formation of monodispersed organic/inorganic hybrid microspheres through urea-formaldedyde (UF) polymerization and (2) removal of the organic template and phase transformation of Fe{sub 3}O{sub 4} to gamma-Fe{sub 2}O{sub 3} by calcination at elevated temperatures. The as-synthesized particles obtained by heating at temperature 300 deg. C feature spherical shape and uniform particle size (d{sub particle}=1.72 mum), high saturation magnetization (M{sub s}=17.22 emu/g), superparamagnetism (M{sub r}/M{sub s}=0.023), high surface area (S{sub BET}=240 m{sup 2}/g), and mesoporosity (d{sub pore}=6.62 nm). The composite microsphere consists of interlocked amorphous SiO{sub 2} nanoparticles, in which cubic gamma-Fe{sub 2}O{sub 3} nanocrystals are homogeneously dispersed and thermally stable against gamma- to alpha-phase transformation at temperatures up to 600 deg. C. With the exposed iron oxide nanoparticles coated with a thin layer of silica shell, the magnetic microspheres were used as a solid-phase adsorbent for rapid extraction of genomic DNA from plant samples. The results show that the DNA templates isolated from pea and green pepper displayed single bands with molecular weights greater than 8 kb and A{sub 260}/A{sub 280} values of 1.60-1.72. The PCR amplification of a fragment encoding the endogenous chloroplast ndhB gene confirmed that the DNA templates obtained were inhibitor-free and amenable to sensitive amplification-based DNA technologies.

  7. Synthesis, characterisation and drug release properties of microspheres of polystyrene with aliphatic polyester side-chains.

    Science.gov (United States)

    Kukut, Manolya; Karal-Yilmaz, Oksan; Yagci, Yusuf

    2014-01-01

    A series of graft copolymers consisting of polystyrene backbone with biocompatible side chains based on (co)polymers of l-lactic acid and glycolic acid were synthesised by combination two controlled polymerisations, namely, nitroxide mediated radical polymerisation (NMRP) and ring opening polymerisation (ROP) with "Click" chemistry. The main goal of this work was to design new biodegradable microspheres using obtained graft copolymers for long-term sustained release of imatinib mesylate (IMM) as a model drug. The IMM loaded microspheres of the graft copolymers, polystyrene-g-poly(lactide-co-glycolide) (PS-g-PLLGA), polystyrene-g-poly(lactic acid) (PS-g-PLLA) and poly(lactic-coglycolic acid) (PLLGA) were then prepared by a modified water-in-oil-in-water (w1/o/w2) double emulsion/solvent evaporation technique. The optimised microspheres were characterised by particle size, encapsulation efficiency, and surface morphology also; their degradation and release properties were studied in vitro. The degradation studies of three different types of microspheres showed that the PS backbone of the graft copolymers slows down the degradation rate compared to PLLGA.

  8. Chemical template-assisted synthesis of monodisperse rattle-type Fe3O4@C hollow microspheres as drug carrier.

    Science.gov (United States)

    Cheng, Lin; Ruan, Weimin; Zou, Bingfang; Liu, Yuanyuan; Wang, Yongqiang

    2017-08-01

    A chemical template strategy was put forward to synthesize monodisperse rattle-type magnetic carbon (Fe3O4@C) hollow microspheres. During the synthesis procedure, monodisperse Fe2O3 microspheres were used as chemical template, which released Fe(3+) ions in acidic solution and initiated the in-situ polymerization of pyrrole into polypyrrole (PPy) shell. With the continual acidic etching of Fe2O3 microspheres, rattle-type Fe2O3@PPy microspheres were generated with the cavity appearing between the PPy shell and left Fe2O3 core, which were then transformed into Fe3O4@C hollow microspheres through calcination in nitrogen atmosphere. Compared with traditional physical template, the shell and cavity of rattle-type hollow microspheres were generated in one step using the chemical template method, which obviously saved the complex procedures including the coating and removal of middle shells. The experimental results exhibited that the rattle-type Fe3O4@C hollow microspheres with different parameters could be regulated through controlled synthesis of the intermediate Fe2O3@PPy product. Moreover, when the rattle-type Fe3O4@C hollow microspheres were investigated as drug carrier, they manifested sustained-release behaviour of doxorubicin, justifying their promising applications as carriers in drug delivery. The aim of the present study was first to synthesize rattle-type Fe3O4@C hollow microspheres through a simple synthesis method as a drug carrier. Here a chemical template synthesis of rattle-type hollow microspheres was developed, which saved the complex procedures including the coating and removal of middle shells in traditional physical template. Second, all the influence factors in the reaction processes were systematically investigated to obtain rattle-type Fe3O4@C hollow microspheres with controlled parameters. Third, the rattle-type Fe3O4@C hollow microspheres were studied as drug carriers and the influences of their structural parameters on drug loading and

  9. Polystyrene Microbeads by Dispersion Polymerization: Effect of Solvent on Particle Morphology

    Directory of Open Access Journals (Sweden)

    Lei Jinhua

    2014-01-01

    Full Text Available Polystyrene microspheres (PS were synthesized by dispersion polymerization in ethanol/2-Methoxyethanol (EtOH/EGME blend solvent using styrene (St as monomer, azobisisobutyronitrile (AIBN as initiator, and PVP (polyvinylpyrrolidone K-30 as stabilizer. The typical recipe of dispersion polymerization is as follows: St/Solvent/AIBN/PVP = 10 g/88 g/0.1 g/2 g. The morphology of polystyrene microspheres was characterized by the scanning electron microscopy (SEM and the molecular weights of PS particles were measured by the Ubbelohde viscometer method. The effect of ethanol content in the blend solvent on the morphology and molecular weight of polystyrene was studied. We found that the size of polystyrene microspheres increased and the molecular weight of polystyrene microspheres decreased with the decreasing of the ethanol content in the blend solvent from 100 wt% to 0 wt%. What is more, the size monodispersity of polystyrene microspheres was quite good when the pure ethanol or pure 2-Methoxyethanol was used; however when the blend ethanol/2-Methoxyethanol solvent was used, the polystyrene microspheres became polydisperse. We further found that the monodispersity of polystyrene microspheres can be significantly improved by adding a small amount of water into the blend solvent; the particles became monodisperse when the content of water in the blend solvent was up to 2 wt%.

  10. Porous titania/carbon hybrid microspheres templated by in situ formed polystyrene colloids.

    Science.gov (United States)

    Cheng, Ting; Zhang, Guoqiang; Xia, Yonggao; Sun, Zaicheng; Yang, Zhaohui; Liu, Rui; Xiao, Ying; Wang, Xiaoyan; Wang, Meimei; Ban, Jianzhen; Yang, Liangtao; Ji, Qing; Qiu, Bao; Chen, Guoxin; Chen, Huifeng; Lin, Yichao; Pei, Xiaoying; Wu, Qiang; Meng, Jian-Qiang; Liu, Zhaoping; Chen, Liang; Xiao, Tonghu; Sun, Ling-Dong; Yan, Chun-Hua; Butt, Hans Jürgen; Cheng, Ya-Jun

    2016-05-01

    A new strategy to synthesize hierarchical, porous titania/carbon (TiO2/C) hybrid microspheres via solvothermal reaction in N,N'-dimethyl formamide (DMF) has been developed. In situ formed polystyrene (PS) colloids have been used as templating agent and carbon source, through which TiO2/PS microspheres with a diameter of ca. 1 μm are built by packed TiO2 nanoparticles of tens of nanometers. The TiO2/PS microspheres are converted to TiO2/C microspheres with different amounts of carbon under controlled calcination condition. The mechanism investigation unveils that the introduction of concentrated HCl creates surface tension between PS and DMF, leading to the formation of PS colloids in solution. The solvothermal treatment further promotes the formation of PS colloids and integration of the titania nanoparticles within the PS colloids. The morphology, crystallinity, nature and content of carbon, UV-Vis absorption, carbon doping, pore size distribution, pore volume, and BET surface area of the TiO2 microspheres with different amounts of carbon have been measured. The applications of the TiO2/C hybrid microspheres as photo catalyst for water splitting and lithium-ion battery anode have been demonstrated. Superior photo catalytic activity for hydrogen conversion under both full spectrum and visible light illumination compared to commercial P25 has been observed for the TiO2/C microspheres with 2 wt% of carbon. Besides, the TiO2/C microspheres with 8 wt% of carbon as lithium-ion battery anode showed a much higher capacity than the bare TiO2 microsphere anode. The origin for the enhanced performance as photo catalyst and lithium-ion battery anode is discussed.

  11. Lignocellulose Nanofiber-Reinforced Polystyrene Produced from Composite Microspheres Obtained in Suspension Polymerization Shows Superior Mechanical Performance.

    Science.gov (United States)

    Ballner, Daniel; Herzele, Sabine; Keckes, Jozef; Edler, Matthias; Griesser, Thomas; Saake, Bodo; Liebner, Falk; Potthast, Antje; Paulik, Christian; Gindl-Altmutter, Wolfgang

    2016-06-01

    A facile approach to obtaining cellulose nanofiber-reinforced polystyrene with greatly improved mechanical performance compared to unreinforced polystyrene is presented. Cellulose nanofibers were obtained by mechanical fibrillation of partially delignified wood (MFLC) and compared to nanofibers obtained from bleached pulp. Residual hemicellulose and lignin imparted amphiphilic surface chemical character to MFLC, which enabled the stabilization of emulsions of styrene in water. Upon suspension polymerization of styrene from the emulsion, polystyrene microspheres coated in MFLC were obtained. When processed into polymer sheets by hot-pressing, improved bending strength and superior impact toughness was observed for the polystyrene-MFLC composite compared to the un-reinforced polystyrene.

  12. CO2 Biofixation of Actinobacillus succinogenes Through Novel Amine-Functionalized Polystyrene Microsphere Materials.

    Science.gov (United States)

    Zhu, Wenhao; Li, Qiang; Dai, Ning

    2017-02-01

    CO2-derived succinate production was enhanced by Actinobacillus succinogenes through polystyrene (PSt) microsphere materials for CO2 adsorption in bioreactor, and the adhesion forces between A. succinogenes bacteria and PSt materials were characterized. Synthesized uniformly sized and highly cross-linked PSt microspheres had high specific surface areas. After modification with amine functional groups, the novel amine-functionalized PSt microspheres exhibited a high adsorption capacity of 25.3 mg CO2/g materials. After addition with the functionalized microspheres into the culture broth, CO2 supply to the cells increased. Succinate production by A. succinogenes can be enhanced from 29.6 to 48.1 g L(-1). Moreover, the characterization of interaction forces between A. succinogenes cells and the microspheres indicated that the maximal adhesive force was about 250 pN. The amine-functionalized PSt microspheres can adsorb a large amount of CO2 and be employed for A. succinogenes anaerobic cultivation in bioreactor for high-efficiency production of CO2-derived succinate.

  13. Interchain tube pressure effect in extensional flows of oligomer diluted nearly monodisperse polystyrene melts

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.; Huang, Qian

    2014-01-01

    We have derived a constitutive equation to explain the extensional dynamics of oligomer-diluted monodisperse polymers, if the length of the diluent has at least two Kuhn steps. These polymer systems have a flow dynamics which distinguish from pure monodisperse melts and solutions thereof, if the ...

  14. Self-assembly of monodisperse polymer microspheres from PPQ-b-PEG rod-coil block copolymers in selective solvents

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xueao; CHEN Ke; XIE Kai; LONG Yongfu

    2005-01-01

    Poly(phenylquinoline)-block-poly(ethylene glycol)(PPQ-b-PEG) rod-coil block copolymers possess the self-assembly behavior in selective solvents. The copolymers in the mixed solvents of V(trifluoroacetic acid, TFA):V(dichloromethane, DCM)=1:1 can self-assemble into polymer hollow microspheres with diameters of a few micrometers. The polymer hollow microspheres are monodisperse, and the diameters of them increase with an increased polymerization degree of the PPQ rigid-rod block. The solution concentration has no effect on the microsphere diameter, but spherical surface shows burrs when the solution concentration is too low. It has been found that the obtained dilute solution has the strongest absorption peak at 376 nm and strongest emission peak at 604 nm by the spectroscopy analysis.

  15. Comparative DNA isolation behaviours of silica and polymer based sorbents in batch fashion: monodisperse silica microspheres with bimodal pore size distribution as a new sorbent for DNA isolation.

    Science.gov (United States)

    Günal, Gülçin; Kip, Çiğdem; Eda Öğüt, S; İlhan, Hasan; Kibar, Güneş; Tuncel, Ali

    2017-03-22

    Monodisperse silica microspheres with bimodal pore-size distribution were proposed as a high performance sorbent for DNA isolation in batch fashion under equilibrium conditions. The proposed sorbent including both macroporous and mesoporous compartments was synthesized 5.1 μm in-size, by a "staged shape templated hydrolysis and condensation method". Hydrophilic polymer based sorbents were also obtained in the form of monodisperse-macroporous microspheres ca 5.5 μm in size, with different functionalities, by a developed "multi-stage microsuspension copolymerization" technique. The batch DNA isolation performance of proposed material was comparatively investigated using polymer based sorbents with similar morphologies. Among all sorbents tried, the best DNA isolation performance was achieved with the monodisperse silica microspheres with bimodal pore size distribution. The collocation of interconnected mesoporous and macroporous compartments within the monodisperse silica microspheres provided a high surface area and reduced the intraparticular mass transfer resistance and made easier both the adsorption and desorption of DNA. Among the polymer based sorbents, higher DNA isolation yields were achieved with the monodisperse-macroporous polymer microspheres carrying trimethoxysilyl and quaternary ammonium functionalities. However, batch DNA isolation performances of polymer based sorbents were significantly lower with respect to the silica microspheres.

  16. 聚苯乙烯/二氧化锰复合微球的合成与表征%Synthesis and characterization of polystyrene/β-manganese dioxide organic/inorganic composite microspheres

    Institute of Scientific and Technical Information of China (English)

    张艳萍; 钱建华; 刘琳; 王莉丽; 王晓旭

    2012-01-01

    Uniform polystyrene/β-manganese dioxide organic/inorganic composite microspheres were prepared by an easy and economical approach.Monodispersed sulfonated polystyrene(PS) microspheres were used as templates as well as the core of the composite microspheres,the shell layers were consist of close accumulated manganese dioxide nanorods and obtained through a hydrothermal reaction of Mn (CH3COO)2 and ammonium persulfate ((NH4)2S2O8) at 140℃.Scanning electron microscopy(SEM) and transmission electron microscopy(TEM)studies show that the as-obtained products consist of large scale composite microspheres.A possible mechanism for the formation of composite microspheres is also proposed in the paper.%本文利用聚苯乙烯微球为模板水热合成了聚苯乙烯/二氧化锰有机无机复合微球.复合微球核层为聚苯乙烯微球,壳层是由大量的二氧化锰纳米棒紧密堆积形成的.利用扫描电子显微镜及透射电子显微镜表征可以看出产物含有大量的复合微球,对于可能的反应机理进行了讨论.

  17. Kinetics of successive seeding of monodisperse polystyrene latexes. I - Initiation via potassium persulfate. II - Azo initiators with and without inhibitors

    Science.gov (United States)

    Sudol, E. D.; El-Aasser, M. S.; Vanderhoff, J. W.

    1986-01-01

    The polymerization kinetics of monodisperse polystyrene latexes with diameters of 1 micron are studied. The monodisperse latexes were prepared by the successive seeding method using 1 mM K2S2O8 with an 8 percent emulsifier surface coverage and 0.5 mM K2S2O8 with a 4 percent emulsifier surface coverage, and the kinetics were measured in a piston/cylinder dialometer. The data reveal that the polymerization rate decreases with increasing particle size; and the surface charge decreases with increasing particle size. The effects of initiators (AIBN and AMBN) and inhibitors (NH24SCN, NaNO2, and hydroquinone) on the product monodispersity and polymerization kinetics of latexes with diameters greater than 1 micron are investigated in a second experiment. It is observed that hydroquinone combined with AMBN are most effective in reducing nucleation without causing flocculation. It is noted that the kinetic transition from emulsion to bulk is complete for a particle size exceeding 1 micron in which the polymerization rate is independent of the particle size.

  18. Interfacial Fast Release Layer in Monodisperse Poly (lactic-co-glycolic acid) Microspheres Accelerates the Drug Release.

    Science.gov (United States)

    Wu, Jun; Zhao, Xiaoli; Yeung, Kelvin W K; To, Michael K T

    2016-01-01

    Understanding microstructural evolutions of drug delivery devices during drug release process is essential for revealing the drug release mechanisms and controlling the drug release profiles. In this study, monodisperse poly (lactic-co-glycolic acid) microspheres in different diameters were fabricated by microfluidics in order to find out the relationships between the microstructural evolutions and the drug release profiles. It was found that poly (lactic-co-glycolic acid) microspheres underwent significant size expansion which took place from the periphery to the center, resulting in the formation of interfacial fast release layers. At the same time, inner pores were created and the diffusion rate was increased so that the early stage drug release was accelerated. Due to the different expansion rates, small poly (lactic-co-glycolic acid) microspheres tendered to follow homogeneous drug release while large poly (lactic-co-glycolic acid) microspheres tendered to follow heterogeneous drug release. This study suggests that the size expansion and the occurrence of interfacial fast release layer were important mechanisms for early stage drug release of poly (lactic-co-glycolic acid) microspheres.

  19. Quantitative prediction of transient and steady-state elongational viscosity of nearly monodisperse polystyrene melts

    DEFF Research Database (Denmark)

    Wagner, Manfred H.; Kheirandish, Saeid; Hassager, Ole

    2005-01-01

    Elongational behavior of four narrow molar mass distribution polystyrene melts of masses 50 000, 100 000, 200 000, and 390 000, g/mol, respectively was investigated up to Hencky strains of 5. All melts show strain hardening behavior. For the two highest molar mass polystyrenes, strain hardening s...

  20. Removal of Cryptosporidium and polystyrene microspheres from swimming pool water with sand, cartridge, and precoat filters.

    Science.gov (United States)

    Amburgey, James E; Walsh, Kimberly J; Fielding, Roy R; Arrowood, Michael J

    2012-03-01

    Cryptosporidium has caused the majority of waterborne disease outbreaks in treated recreational water venues in the USA for many years running. This research project evaluated some common US swimming pool filters for removing Cryptosporidium oocysts, 5-µm diameter polystyrene microspheres, and 1-µm diameter polystyrene microspheres. A 946 L hot tub with interchangeable sand, cartridge, and precoat filters was used at room temperature for this research. Simulated pool water for each experiment was created from Charlotte, NC (USA) tap water supplemented with alkalinity, hardness, chlorine, and a mixture of artificial sweat and urine. Precoat (i.e., diatomaceous earth and perlite) filters demonstrated pathogen removal efficiencies of 2.3 to 4.4 log (or 99.4-99.996%). However, sand and cartridge filters had average Cryptosporidium removals of 0.19 log (36%) or less. The combined low filter removal efficiencies of sand and cartridge filters along with the chlorine-resistant properties of Cryptosporidium oocysts could indicate a regulatory gap warranting further attention and having significant implications on the protection of public health in recreational water facilities. The 5-µm microspheres were a good surrogate for Cryptosporidium oocysts in this study and hold promise for use in future research projects, field trials, and/or product testing on swimming pool filters.

  1. Assessment of active pharmaceutical ingredient particle size in tablets by Raman chemical imaging validated using polystyrene microsphere size standards.

    Science.gov (United States)

    Kuriyama, Atsushi; Ozaki, Yukihiro

    2014-04-01

    Particle size is a critical parameter for controlling pharmaceutical quality. The aim of this study was to assess the size of the micrometer-scale active pharmaceutical ingredients (API) in tablets using Raman chemical imaging and to understand the effects of formulation on particle size. Model tablets containing National Institute of Standards and Technology traceable polystyrene microsphere size standards were developed to determine the binarization threshold value of Raman chemical images for API particle sizing in specific formulations and processes. Three sets of model tablets containing 5, 10, and 15 μm polystyrene microspheres, used to mimic API, were prepared using a commercial tablet formulation (Ebastel tablets, mean API particle size was about 5 μm). Raman mapping with a 50× objective (NA, 0.75) was applied to tablet cross-sections, and particle size of polystyrene microspheres was estimated from binary images using several binarization thresholds. Mean particle size for three sets of polystyrene microspheres showed good agreement between pre- and postformulation (the slope = 1.024, R = 1.000) at the specific threshold value ((mean + 0.5σ) of the polystyrene-specific peak intensity histogram), regardless of particle agglomeration, tablet surface roughness, and laser penetration depth. The binarization threshold value showed good applicability to Ebastel tablets, where the API-specific peak intensity histogram showed a pattern similar to that of polystyrene microspheres in model tablets. The model tablets enabled determination of an appropriate binarization threshold for assessing the mean particle size of micrometer-scale API in tablets by utilizing the unique physicochemical properties of polystyrene microspheres.

  2. Formation of cagelike sulfonated polystyrene microspheres via swelling-osmosis process and loading of CdS nanoparticles.

    Science.gov (United States)

    Weng, Hanqin; Huang, Xuefeng; Wang, Mozhen; Ji, Xiang; Ge, Xuewu

    2013-12-10

    In this report, we studied the formation mechanism of cagelike polymer microspheres fabricated conveniently and efficiently through a swelling-osmosis process of sulfonated polystyrene (SPS) microspheres in a ternary mixed solvent (water/ethanol/heptane). The scanning electron microscopy and transmission electron microscopy observations indicated that the morphology of the final cagelike SPS microspheres is mainly controlled by the composition of the mixed solvent and the swelling temperature. Considering the solubility parameters of related reagents and the low interface tension of heptane and the aqueous solution of ethanol (only 6.9 mN/m), we confirm that the porogen procedure starts from the swelling of SPS microspheres by heptane, followed by the osmosis process of water molecules into the swollen SPS microspheres forced by the strong hydrophilicity of -SO3H group. The water molecules permeated into SPS microspheres will aggregate into water pools, which form the pores after the microspheres are dried. These prepared cagelike SPS microspheres are further served as the scaffold for the in situ generated CdS nanoparticles under γ-ray radiation. The CdS/SPS composite microspheres show good fluorescence performance. This work shows that the cagelike SPS microspheres have a wide industrial application prospect due to their economical and efficient preparation and loading nanoparticles.

  3. Solvothermal synthesis of monodispersed CoZr{sub 4}(PO{sub 4}){sub 6} microspheres and their application as microwave absorber

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Tingting [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Sun, Genban, E-mail: gbsun@bnu.edu.cn [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Ma, Shulan; Yang, Xiaojing [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Hu, Changwen [Key Laboratory of Cluster Science, Ministry of Education of China and Department of Chemistry, Beijing Institute of Technology, Beijing 100081 (China)

    2012-03-15

    Graphical abstract: Monodispersed CoZr{sub 4}(PO{sub 4}){sub 6} porous microspheres with shell structure were synthesized via a combined solvothermal method and calcination route. The radar-wave absorbability of the purple sample calcined at 900 Degree-Sign C was strongest at the frequency of about 8.5 GHz. Highlights: Black-Right-Pointing-Pointer In this study we synthesized monodispersed CoZr{sub 4}(PO{sub 4}){sub 6} porous microspheres as microwave absorber. Black-Right-Pointing-Pointer The relationship between microstructures and the electromagnetic properties was indicated. Black-Right-Pointing-Pointer The radar-wave absorbability of the sample was included. -- Abstract: Monodispersed CoZr{sub 4}(PO{sub 4}){sub 6} microspheres with a diameter of 40 {mu}m were achieved via a combining solvothermal and calcination route. The crystallinity of the calcined microspheres with shell structure was improved, while the monodisperse property and morphologies remained. The possible formation mechanism of the porous CoZr{sub 4}(PO{sub 4}){sub 6} microspheres with nanoshell was proposed. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR) technologies, thermal analysis (TG and DSC), nitrogen adsorption-desorption isotherms and network analyzer. The sample calcined at 900 Degree-Sign C shows a strongest absorbability in the radar-wave absorbability test.

  4. Autoadhesion of High-Molecular-Weight Monodisperse Glassy Polystyrene at unexpected low temperatures

    DEFF Research Database (Denmark)

    Boiko, Yuri M.; Lyngaae-Jørgensen, Jørgen

    2004-01-01

    Healing of symmetric interfaces of amorphous anionically polymerized high- and ultra-high-molecular weight (HMW and UHMW, respectively) polystyrene (PS) in a range of the weight-average molecular weight M-w from 102.5 (M-w/M-n = 1.05) to 1110 kg/ mol (M-w/M-n = 1.15) was followed at a constant...

  5. One-pot synthesis and visible light photocatalytic activity of monodispersed AgIn{sub 5}S{sub 8} microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiangqing [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China); Wang, Lei; Wei, Dailong [School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Kang, Shizhao [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China); Mu, Jin, E-mail: mujin@sit.edu.cn [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China)

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► Monodispersed AgIn{sub 5}S{sub 8} microspheres were prepared in a one-pot process. ► The process is environmental friendly. ► The AgIn{sub 5}S{sub 8} microspheres display high photocatalytic activity. -- Abstract: Monodispersed AgIn{sub 5}S{sub 8} microspheres were synthesized using a one-pot solution method and characterized with X-ray diffraction, UV–vis diffuse reflectance spectroscopy, scanning electron microscope, energy dispersive X-ray spectroscopy and N{sub 2} adsorption–desorption isotherm. The results indicated that the AgIn{sub 5}S{sub 8} microspheres were of cubic spinel structure and the mean diameter of about 0.5 μm. In addition, the visible light photocatalytic activity of AgIn{sub 5}S{sub 8} microspheres was also investigated at room temperature. The AgIn{sub 5}S{sub 8} microspheres showed very high photocatalytic activity for the degradation of methyl orange with a degradation efficiency of about 98% under visible light irradiation for 20 min.

  6. Polystyrene-based Hollow Microsphere Synthesized by [gamma]-ray Irradiation-assisted Polymerization and Self-Assembly and Its Application in Detection of Ionizing Radiation

    National Research Council Canada - National Science Library

    Wenhui Fan; Qing Li; Liang Hu; Siqi Yan; Wanxin Wen; Zhifang Chai; Hanzhou Liu

    2017-01-01

    .... Here, a simple and novel one-pot synthetic strategy to prepare polystyrene (PS) hollow microspheres via irradiation-assisted free-radical polymerizing and self-assembly (IFPS) approach under γ...

  7. Synthesis and application of monodisperse oligo(oxyethylene)-grafted polystyrene resins for solid-phase organic synthesis.

    Science.gov (United States)

    Lumpi, Daniel; Braunshier, Christian; Horkel, Ernst; Hametner, Christian; Fröhlich, Johannes

    2014-07-14

    In a preliminary investigation by our group, we found that poly(styrene-oxyethylene) graft copolymers (PS-PEG), for example, TentaGel resins, are advantageous for gel-phase (13)C NMR spectroscopy. Because of the solution-like environment provided by the PS-PEG resins, good spectral quality of the attached moiety can be achieved, which is useful for nondestructive on-resin analysis. The general drawbacks of such resins are low loading capacities and the intense signal in the spectra resulting from the PEG linker (>50 units). Here, we describe the characterization of solvent-dependent swelling and reaction kinetics on a new type of resin for solid-phase organic synthesis (SPOS) that allows an accurate monitoring by gel-phase NMR without the above disadvantages. A series of polystyrene-oligo(oxyethylene) graft copolymers containing monodisperse PEG units (n = 2-12) was synthesized. A strong correlation between the linker (PEG) length and the line widths in the (13)C gel-phase spectra was observed, with a grafted PEG chain of 8 units giving similar results in terms of reactivity and gel-phase NMR monitoring to TentaGel resin. Multistep on-resin reaction sequences were performed to prove the applicability of the resins in solid-phase organic synthesis.

  8. Producing monodisperse drug-loaded polymer microspheres via cross-flow membrane emulsification: the effects of polymers and surfactants.

    Science.gov (United States)

    Meyer, Robert F; Rogers, W Benjamin; McClendon, Mark T; Crocker, John C

    2010-09-21

    Cross-flow membrane emulsification (XME) is a method for producing highly uniform droplets by forcing a fluid through a small orifice into a transverse flow of a second, immiscible fluid. We investigate the feasibility of using XME to produce monodisperse solid microspheres made of a hydrolyzable polymer and a hydrophobic drug, a model system for depot drug delivery applications. This entails the emulsification of a drug and polymer-loaded volatile solvent into water followed by evaporation of the solvent. We use a unique side-view visualization technique to observe the details of emulsion droplet production, providing direct information regarding droplet size, dripping frequency, wetting of the membrane surface by the two phases, neck thinning during droplet break off, and droplet deformation before and after break off. To probe the effects that dissolved polymers, surfactants, and dynamic interfacial tension may have on droplet production, we compare our results to a polymer and surfactant-free fluid system with closely matched physical properties. Comparing the two systems, we find little difference in the variation of particle size as a function of continuous phase flow rate. In contrast, at low dripping frequencies, dynamic interfacial tension causes the particle size to vary significantly with drip frequency, which is not seen in simple fluids. No effects due to shear thinning or fluid elasticity are detected. Overall, we find no significant impediments to the application of XME to forming highly uniform drug-loaded microspheres.

  9. Autoadhesion of High-Molecular-Weight Monodisperse Glassy Polystyrene at unexpected low temperatures

    DEFF Research Database (Denmark)

    Boiko, Yuri M.; Lyngaae-Jørgensen, Jørgen

    2004-01-01

    -bulk corresponding to a second-order phase transition temperature). To our knowledge, this is the first observation of such nature, which gives further evidence of the lowering of the T-g at polymeric surfaces and the persistence of this effect at early stages of healing of polymer-polymer interfaces.......Healing of symmetric interfaces of amorphous anionically polymerized high- and ultra-high-molecular weight (HMW and UHMW, respectively) polystyrene (PS) in a range of the weight-average molecular weight M-w from 102.5 (M-w/M-n = 1.05) to 1110 kg/ mol (M-w/M-n = 1.15) was followed at a constant...... healing temperature, T-h, well below the glass transition temperature of the polymer bulk [Tg-bulk = 105 - 106degreesC as measured by differential scanning calorimeter (DSC)]. The bonded interfaces were shear fractured in tension on an Instron tester at ambient temperature. Autoadhesion at symmetric HMW...

  10. Protecting metal-organic framework crystals from hydrolytic degradation by spray-dry encapsulating them into polystyrene microspheres.

    Science.gov (United States)

    Carné-Sánchez, Arnau; Stylianou, Kyriakos C; Carbonell, Carlos; Naderi, Majid; Imaz, Inhar; Maspoch, Daniel

    2015-02-04

    Many metal-organic frameworks are water labile, including the iconic Hong-Kong University of Science and Technology-1 (HKUST-1). Spray-dry encapsulation of HKUST-1 crystals into polystyrene microspheres is reported here to yield composites that are resistant to water but retain most of the excellent gas sorption capacity of HKUST-1. These composites are demonstrated to exhibit superior water adsorption/desorption cycling, maintaining the level of water uptake even after three cycles.

  11. Protecting Metal-Organic Framework Crystals from Hydrolytic Degradation by Spray-Dry Encapsulating Them into Polystyrene Microspheres

    OpenAIRE

    Carné-Sánchez, Arnau; Stylianou, Kyriakos C.; Carbonell, Carlos; Naderi, MajidImaz; Imaz, Inhar; Maspoch, Daniel

    2014-01-01

    Many metal-organic frameworks are water labile, including the iconic Hong-Kong University of Science and Technology-1 (HKUST-1). Spray-dry encapsulation of HKUST-1 crystals into polystyrene microspheres is reported here to yield composites that are resistant to water but retain most of the excellent gas sorption capacity of HKUST-1. These composites are demonstrated to exhibit superior water adsorption/desorption cycling, maintaining the level of water uptake even after three cycles.

  12. Contact electrification in aerosolized monodispersed silica microspheres quantified using laser based velocimetry

    DEFF Research Database (Denmark)

    Alois, Stefano; Merrison, Jonathan P.; Iversen, Jens Jacob

    2017-01-01

    The contact electrification of aerosolized micro particles has been studied using a novel technique involving laser velocimetry. This has allowed the simultaneous determination of size and electrical charge of individual silica microspheres (in the range 1 – 8 µm). Interestingly the particles...

  13. Micro-spherical cochleate composites: method development for monodispersed cochleate system.

    Science.gov (United States)

    Nagarsekar, Kalpa; Ashtikar, Mukul; Steiniger, Frank; Thamm, Jana; Schacher, Felix H; Fahr, Alfred

    2017-03-01

    Cochleates have been of increasing interest in pharmaceutical research due to their extraordinary stability. However the existing techniques used in the production of cochleates still need significant improvements to achieve sufficiently monodispersed formulations. In this study, we report a simple method for the production of spherical composite microparticles (3-5 μm in diameter) made up of nanocochleates from phosphatidylserine and calcium (as binding agent). Formulations obtained from the proposed method were evaluated using electron microscopy and small angle X-ray scattering and were compared with conventional cochleate preparation techniques. In this new method, an ethanolic lipid solution and aqueous solution of a binding agent is subjected to rapid and uniform mixing with a microfluidic device. The presence of high concentration of organic solvent promotes the formation of composite microparticles made of nanocochleates. This simple methodology eliminates elaborate preparation methods, while providing a monodisperse cochleate system with analogous quality.

  14. Synthesis of polystyrene microspheres and functionalization with Pd(0) nanoparticles to perform bioorthogonal organometallic chemistry in living cells.

    Science.gov (United States)

    Unciti-Broceta, Asier; Johansson, Emma M V; Yusop, Rahimi M; Sánchez-Martín, Rosario M; Bradley, Mark

    2012-05-31

    We have developed miniaturized heterogeneous Pd(0)-catalysts (Pd(0)-microspheres) with the ability to enter cells, stay harmlessly within the cytosol and mediate efficient bioorthogonal organometallic chemistries (e.g., allylcarbamate cleavage and Suzuki-Miyaura cross-coupling). This approach is a major addition to the toolbox available for performing chemical reactions within cells. Here we describe a full protocol for the synthesis of the Pd(0)-microspheres from readily available starting materials (by the synthesis of size-controlled amino-functionalized polystyrene microspheres), as well as for their characterization (electron microscopy and palladium quantitation) and functional validation ('in solution' and 'in cytoplasm' conversions). From the beginning of the synthesis to functional evaluation of the catalytic device requires 5 d of work.

  15. 单分散ZnO微球的合成及表征%Synthesis of monodispersed ZnO microspheres and characterizations

    Institute of Scientific and Technical Information of China (English)

    颜蔚; 安明; 王响; 董琪琪; 孙丽宁; 施利毅; 邓维

    2012-01-01

    采用简单的两步法合成了直径范围从50~200 nm的单分散的ZnO微球:在第一步反应中制备了ZnO纳米粒子的乙醇分散液;然后在第二步反应中加入适量的ZnO纳米粒子的乙醇分散液,从而合成出单分散的ZnO微球.通过改变第二步反应中所加入的ZnO纳米粒子的乙醇分散液的量,可以改变制备的单分散ZnO微球的直径.通过透射电子显微镜和X-射线衍射分析可以得知,ZnO微球是由ZnO纳米粒子聚集而成.不论ZnO微球的直径是多少,其多分散指数均小于1,并且当ZnO微球的直径为150 nm时,其多分散指数仅为0.16.%In this paper, monodispersed ZnO microspheres in sizes from 50 to 200 nm were synthesized with a developed two-step method. In the primary reaction, ethanol suspension of ZnO nanoparticles was prepared, and monodispersed ZnO microspheres were synthesized in the secondary reaction by adding the ZnO nanoparticles suspension into the reaction solution. Diameter of the ZnO microspheres could be controlled by varying the volume of QDs suspension added. The transmission microscopy images and X-ray diffraction patterns of the ZnO microspheres showed that no matter their diameters, the ZnO microspheres were formed by aggregation of well crystallized ZnO nanoparticles. The polydispersity indexes (PDI) of ZnO microspheres were detected. It is found that PDI values of the microspheres were all less than 1. 0, suggesting the monodispersi-ty of the ZnO microspheres. The PDI value was only 0. 16 when the diameter of the ZnO microspheres was 150 nm.

  16. Polystyrene microspheres enable 10‐color compensation for immunophenotyping of primary human leukocytes

    Science.gov (United States)

    Carr, Karen D.; Norman, John C.; Huye, Leslie; Hegde, Meenakshi

    2015-01-01

    Abstract Compensation is a critical process for the unbiased analysis of flow cytometry data. Numerous compensation strategies exist, including the use of bead‐based products. The purpose of this study was to determine whether beads, specifically polystyrene microspheres (PSMS) compare to the use of primary leukocytes for single color based compensation when conducting polychromatic flow cytometry. To do so, we stained individual tubes of both PSMS and leukocytes with panel specific antibodies conjugated to fluorochromes corresponding to fluorescent channels FL1‐FL10. We compared the matrix generated by PSMS to that generated using peripheral blood mononuclear cells (PBMC). Ideal for compensation is a sample with both a discrete negative population and a bright positive population. We demonstrate that PSMS display autofluorescence properties similar to PBMC. When comparing PSMS to PBMC for compensation PSMS yielded more evenly distributed and discrete negative and positive populations to use for compensation. We analyzed three donors' PBMC stained with our 10‐color T cell subpopulation panel using compensation generated by PSMS vs.PBMC and detected no significant differences in the population distribution. Panel specific antibodies bound to PSMS represent an invaluable valid tool to generate suitable compensation matrices especially when sample material is limited and/or the sample requires analysis of dynamically modulated or rare events. © 2015 The Authors. Cytometry Part A Published by Wiley Periodicals, Inc. PMID:26202733

  17. Facile synthesis of superhydrophobic TiO2/polystyrene core-shell microspheres

    Directory of Open Access Journals (Sweden)

    2011-01-01

    Full Text Available In this paper, core-shell TiO2/polystyrene (TiO2/PS microspheres with superhydrophobic properties were prepared via a facile method. Our method needs neither special apparatus nor complicated chemical treatment. The whole process includes two steps: firstly, coupling agent was used to modify TiO2 by sol-gel method; secondly, fabrication of TiO2/PS dispersions was carried out via in-situ free-radical polymerization strategy. The component and structure of the TiO2/PS particles were characterized by Fourier transform infrared (FTIR spectroscopy, thermogravimetric analysis (TGA, field emission scanning electron microscope (FE-SEM and transmission electron microscopy (TEM. The TiO2 gel particles with average diameter of 1 μm exhibited irregular spherical shape and obvious aggregation. Compared with the TiO2 particles, the resulting TiO2/PS particulates showed regular spherical shape, better dispersion and bigger size. By directly depositing the resulted TiO2/PS dispersion on a Cu foil, the coating showed superhydrophobic property which was reflected by the contact angle (CA of water on the surface with high water adhesion. The apparent CA of water is 153.5±1.5°, suggesting that this composite possesses well superhydrophobicity.

  18. Synthesis of polystyrene@(silver–polypyrrole) core/shell nanocomposite microspheres and study on their antibacterial activities

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Longhai; Ren, Shanshan; Qiu, Teng, E-mail: qiuteng@mail.buct.edu.cn; Wang, Leilei; Zhang, Jiangru; He, Lifan; Li, Xiaoyu, E-mail: lixy@mail.buct.edu.cn [Ministry of Education, Beijing University of Chemical Technology, Key Laboratory of Carbon Fiber and Functional Polymer (China)

    2015-01-15

    We reported the synthesis of polystyrene@(silver–polypyrrole) (PS@(Ag–PPy)) nanocomposite microspheres with the well-defined core/shell structure, in which the functionalized PS microspheres by the sulfonic acid groups were employed as template. The diameter of the synthesized PS microsphere template and AgNP was 1.26 μm and 50 nm, respectively. In order to well control the redox reaction between Ag{sup +} and Py monomer and to avoid the accumulation of these AgNPs during synthesis process, the complexation of triethanolamine (TEA) and silver ion ([Ag(TEA){sub 2}]{sup +}) was employed as the oxidant, so that the generation rate of AgNPs was in turn decreased. Moreover, compared with the redox reaction between AgNO{sub 3} and Py, the introduction of [Ag(TEA){sub 2}]{sup +} ions resulted in the improved coverage and distribution of AgNPs around the surface of PS microspheres. Meanwhile, the loading amount of Ag–PPy nanocomposites on the final microspheres was adjustable. The increasing concentrations of Py monomer and [Ag(TEA){sub 2}]{sup +} ions resulted in the increase of Ag–PPy nanocomposite loading. The results of antibacterial experiment suggested that the synthesized PS@(Ag–PPy) composite microspheres showed the prominent antibacterial properties against both the Gram-negative bacteria of Escherichia coli and the Gram-positive bacteria of Staphylococcus aureus. For the bacteria with concentration at 1 × 10{sup 5} – 9×10{sup 5} cfu/mL, the microspheres can kill the bacteria above 3-log reduction with the concentration of PS@(Ag–PPy) composite microspheres at 50 μg/mL, in which the weight fraction of Py in the composite microspheres was above 10 wt%. When the weight fraction of Py in the composite microspheres was at 5 wt%, the 2-log reduction of in bacterial viability could also be obtained.Graphical Abstract.

  19. HIGH IMMOBILIZATION OF ANTIBACTERIAL MOIETIES ONTO MONODISPERSE MICROSPHERES BY DISPERSION POLYMERIZATION USING BICATIONIC VIOLOGEN SURFMER

    Institute of Scientific and Technical Information of China (English)

    Sheng-liu Wang; Xiao-fang Yang; Lian-ying Liu; Wan-tai Yang

    2012-01-01

    In order to achieve monodisperse particles with high content of antibacterial groups covalently bonded on surface,a bicationic viologen,N-hexyl-N'-(4-vinylbenzyl)-4,4'-bipyridinium bromide chloride (HVV) was devised as a surfmer in dispersion polymerization of styrene (St) using a mixture of methanol (or ethylene glycol) and water as media.Effects of content of HVV,its addition profile and composition of reaction media on particles size and incorporation of HVV moieties were mainly investigated.The attachment of silver and gold nanoparticles on particle surface under UV irradiation ascertained the surface-bonded HVV segments.SEM,TEM observations and XPS,zata potential measurements indicated that increase of initial HVV contents and addition of HVV (when polymerization had been performed for 3 h) led to grown particles and enhanced immobilization of HVV moieties.Using a mixture of ethylene glycol and water as reaction media,small particles (520-142 nm) with highly attached HVV moieties were prepared.Furthermore,antibacterial efficacy of the resultant particles against S.aureus was assayed,and particles with more HVV moieties anchored on surface demonstrated greater efficiency of antibacterial activity.

  20. Monodisperse REPO4 (RE = Yb, Gd, Y) hollow microspheres covered with nanothorns as affinity probes for selectively capturing and labeling phosphopeptides.

    Science.gov (United States)

    Cheng, Gong; Zhang, Ji-Lin; Liu, Yan-Lin; Sun, De-Hui; Ni, Jia-Zuan

    2012-02-13

    Rare-earth phosphate microspheres with unique structures were developed as affinity probes for the selective capture and tagging of phosphopeptides. Prickly REPO(4) (RE = Yb, Gd, Y) monodisperse microspheres, that have hollow structures, low densities, high specific surface areas, and large adsorptive capacities were prepared by an ion-exchange method. The elemental compositions and crystal structures of these affinity probes were confirmed by energy-dispersive spectroscopy (EDS), powder X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectroscopy. The morphologies of these compounds were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen-adsorption isotherms. The potential ability of these microspheres for selectively capturing and labeling target biological molecules was evaluated by using protein-digestion analysis and a real sample as well as by comparison with the widely used TiO(2) affinity microspheres. These results show that these porous rare-earth phosphate microspheres are highly promising probes for the rapid purification and recognition of phosphopeptides.

  1. Tailoring the morphology of raspberry-like carbon black/polystyrene composite microspheres for fabricating superhydrophobic surface

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Yubin [Polymer Alloy Lab., School of Material Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Li, Qiuying, E-mail: liqy@ecust.edu.cn [Polymer Alloy Lab., School of Material Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Shanghai Key Laboratory Polymeric Materials (China); Key Laboratory of Ultrafine Materials of Ministry of Education (China); Xue, Pengfei; Huang, Jianfeng; Wang, Jibin; Guo, Weihong; Wu, Chifei [Polymer Alloy Lab., School of Material Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China)

    2011-05-15

    In our previous report, raspberry-like carbon black/polystyrene (CB/PS) composite microsphere was prepared through heterocoagulation process. Based on the previous study, in the present work, the morphology of raspberry-like CB/PS particle is tailored through adjusting the polarity and the concentration ratio of CB/PS colloidal suspension with the purpose to prepare particulate film for the fabrication of superhydrophobic surface. Scanning electron microscope (SEM) confirms the morphology of raspberry-like particle and the coverage of CB. Rough surfaces fabricated by raspberry-like particles with proper morphology are observed by SEM and clear evidence of superhydrophobic surface is shown. The structure of raspberry-like particle is analyzed by atom force microscope. The proposed relationship between the hydrophobicity and the structure of CB aggregates on the surface of PS microsphere is discussed in details.

  2. A novel magneto-fluorescent microsphere: Preparation and characterization of polystyrene-supported Fe3O4 and CdS nanoparticles

    Science.gov (United States)

    Kaboudin, Babak; Ghaderian, Abolfazl

    2013-10-01

    Novel sulfonated polystyrene microsphere containing Fe3O4 and CdS nanoparticles have been prepared and characterized. A thorough structural characterization has been carried out by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM) images, VSM data, EDS, and photoluminescence spectroscopy. The presence of the magnetic nanoparticles (Fe3O4) and CdS nanoparticles on the polystyrene microspheres has been demonstrated. Cadmium diethyl dithiophosphate (CDDP) has been used as a 3 in 1 precursor (cadmium, sulfur, and ligand source) for the synthesis of high-quality CdS nanoparticles on polystyrene microsphere containing Fe3O4 nanoparticles. This novel composite exhibits both fluorescence and magnetism properties that may be used in a novel bioprobe.

  3. A novel magneto-fluorescent microsphere: Preparation and characterization of polystyrene-supported Fe{sub 3}O{sub 4} and CdS nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kaboudin, Babak, E-mail: kaboudin@iasbs.ac.ir; Ghaderian, Abolfazl

    2013-10-01

    Novel sulfonated polystyrene microsphere containing Fe{sub 3}O{sub 4} and CdS nanoparticles have been prepared and characterized. A thorough structural characterization has been carried out by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM) images, VSM data, EDS, and photoluminescence spectroscopy. The presence of the magnetic nanoparticles (Fe{sub 3}O{sub 4}) and CdS nanoparticles on the polystyrene microspheres has been demonstrated. Cadmium diethyl dithiophosphate (CDDP) has been used as a 3 in 1 precursor (cadmium, sulfur, and ligand source) for the synthesis of high-quality CdS nanoparticles on polystyrene microsphere containing Fe{sub 3}O{sub 4} nanoparticles. This novel composite exhibits both fluorescence and magnetism properties that may be used in a novel bioprobe.

  4. Polystyrene/nano-SiO2 composite microspheres fabricated by Pickering emulsion polymerization: Preparation, mechanisms and thermal properties

    Directory of Open Access Journals (Sweden)

    W. H. Zhang

    2012-07-01

    Full Text Available We report the preparation, mechanisms and thermal properties of core-shell structured polymer/inorganic nanoparticle composite microspheres prepared by Pickering emulsion polymerization. Stable Pickering emulsion was firstly fabricated by using surface-modified nano-SiO2 particles as stabilizer. And then, two kinds of polystyrene/nano-SiO2 (PS/SiO2 composite microspheres with different sizes and morphologies were synthesized using hydrophobic azobisisobutyronitrile (AIBN and hydrophilic ammonium persulfate (APS as initiator, respectively. The possible mechanisms of Pickering emulsion polymerization initiated by different initiators were proposed according to the results of transmission electron microscope (TEM and scanning electron microscope (SEM. The chemical structure and molecular weight of the composite microspheres were characterized by Fourier transform infrared spectroscopy (FTIR, X-ray diffractometer (XRD and gel permeation chromatography coupled with a multi-angle laser light scattering photometer (GPC-MALLS. Thermogravimetric analysis (TGA and differential scanning calorimeter (DSC were used to comparatively analyze the thermal properties of nanocomposites and corresponding pure polymer. The results indicated that the decomposition temperature and glass transition temperature (Tg of nanocomposites were elevated to a certain degree due to the existence of nano-SiO2.

  5. Monodisperse magnetic hydroxyapatite/Fe{sub 3}O{sub 4} microspheres for removal of lead(II) from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Fuqiang [Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo 315211 (China); Tan, Ruiqin, E-mail: tanruiqin@nbu.edu.cn [Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo 315211 (China); Shen, Wenfeng; Zhang, Xianpeng; Xu, Wei; Song, Weijie [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2015-07-15

    Highlights: • Monodisperse HAp/Fe{sub 3}O{sub 4} microspheres were explored for the removal of lead(II). • The sorption capacity toward Pb{sup 2+} reached 440 mg/g at pH 3.0. • Pb{sup 2+}-loaded HAp/Fe{sub 3}O{sub 4} microspheres can be easily collected by magnetic separation. • The removal mechanism of Pb{sup 2+} was different at pH 2.0–6.0. - Abstract: Monodisperse magnetic hydroxyapatite (HAp)/Fe{sub 3}O{sub 4} microspheres were successfully synthesized and explored for the removal of lead(II) from aqueous solution. The mechanism of Pb{sup 2+} uptake was characterized using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. The sorption capacity toward Pb{sup 2+} reached 440 mg/g at pH 3.0 and equilibrium was achieved within 1 h. The experimental data followed the Langmuir isotherm model (R{sup 2} = 0.9969) and the kinetic results accorded with the pseudo-second-order model (R{sup 2} = 0.9970). The sorption of Pb{sup 2+} on the surfaces of HAp/Fe{sub 3}O{sub 4} and the following ion exchange are the primary mechanism at pH 3.0–6.0. The dissolution–precipitation mechanism response to the removal of Pb{sup 2+} when pH varied from 3.0 to 2.0. The Pb{sup 2+}-loaded magnetic HAp/Fe{sub 3}O{sub 4} could be separated conveniently.

  6. One-step synthesis and properties of urchin-like PS/α-Fe2O3 composite hollow microspheres

    Science.gov (United States)

    Zhang, Yanping; Chu, Ying; Dong, Lihong

    2007-10-01

    A new progressive hard template method has been developed to synthesize uniform polystyrene (PS)/α-Fe2O3 composite hollow microspheres under hydrothermal conditions. Sulfonated polystyrene (PS) microspheres were used as templates as well as the endothecia of the composite microspheres; Fe2O3 shell was obtained through the reaction of FeSO4 and KClO3 under hydrothermal conditions. Field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) studies showed that the as-obtained products consist of large scale monodisperse urchin-like hollow microspheres. In comparison with the Fe2O3 of other structures, the composite hollow microspheres have good photocatalytic activity, large surface area and a high remanent magnetization. A possible mechanism for the formation of composite hollow microspheres is also proposed in the paper.

  7. Preparation of polystyrene/SiO2 microsphere via Pickering emulsion polymerization: Synergistic effect of SiO2 concentrations and initiator sorts

    Science.gov (United States)

    Zhou, Haiou; Shi, Tiejun; Zhou, Xun

    2013-02-01

    In this paper, polystyrene (PS)/SiO2 microspheres were successfully prepared via Pickering emulsion polymerization stabilized solely by ethacryloxypropyltrimethoxysilane (MPTMS) modified SiO2 nanoparticles. The formation mechanisms of PS/SiO2 microspheres with different morphology were investigated under various Pickering emulsion polymerization conditions. The results showed that SiO2 concentrations and initiator sorts would synergistically impact on the morphology of products corresponding to distinct formation mechanisms. When SiO2 concentrations was low and water-solute initiator potassium persulfate (KPS) was used, aqueous nucleation was dominant, which was deduced to the formation of dispersive microspheres sparsely anchored by SiO2 particles. When SiO2 concentrations was increased and oil-solute initiator azobisisobutyronitrile (AIBN) was applied, nucleation in oil phase prevailed which lead to the formation of microspheres densely packed by SiO2 particles.

  8. Polystyrene-based Hollow Microsphere Synthesized by γ-ray Irradiation-assisted Polymerization and Self-Assembly and Its Application in Detection of Ionizing Radiation

    Science.gov (United States)

    Fan, Wenhui; Li, Qing; Hu, Liang; Yan, Siqi; Wen, Wanxin; Chai, Zhifang; Liu, Hanzhou

    2017-01-01

    To simply and multitudinously synthesize hollow microspheres in a pure system is important for relevant research and application. Here, a simple and novel one-pot synthetic strategy to prepare polystyrene (PS) hollow microspheres via irradiation-assisted free-radical polymerizing and self-assembly (IFPS) approach under γ-ray irradiation with no additives introduced into the system is presented. And PS/2,5-Diphenyloxazole (PPO) fluorescent microspheres have been prepared successfully by IFPS reaction, which can be used as scintillators for the detection of ionizing radiation. A linear relationship between emitted luminescence and dose-activity in water is obtained, which suggests that composite microspheres could be used as liquid scintillation in specific environment.

  9. 单分散介孔二氧化硅微球的制备%Synthesis of monodisperse mesoporous silica microsphere

    Institute of Scientific and Technical Information of China (English)

    钟立峰; 宁海金; 徐先进; 廖道发

    2012-01-01

    Modified Stober method was used to prepare monodisperse mesoporous silica microsphere by two-step reaction including hydrolysis and condensation of tetraethyl orthosilicate(TEOS)with ammonia as catalyst.Effects of the reaction parameters on the size and mono-disperse of the microsphere were discussed based on many characterization tests.Results showed: the microsphere size increased with the increment of ammonia and TEOS concentrations while decreased at higher temperature due to the evaporation of ammonia;effects of the reaction time on the particle distribution existed mainly in the initial stage,then got smooth gradually.The comparison of small angle X ray analysis suggested that peak intensity of silica microsphere increased and the overlapping peaks drifted rightward after calcination,indicating that the surfactant molecules were removed from the hole and the aperture shrank at the same time.In addition,the texture of the product was affected by reaction conditions to some extent.The mechanism study revealed the formation of silica microsphere was achieved through TEOS hydrolysis and polycondensation two steps successively.This is a simple,effective and repeatable method,which may be used for mass production,for the preparation of mono-dispersed mesoporous silica microspheres.%在Stober方法基础上制备了单分散二氧化硅微球,系统研究了反应条件对成球粒径以及单分散性的影响。通过多种测试手段,发现随着正硅酸乙酯和氨水浓度的提高,成球的粒径逐渐增大;而温度的提高会促使氨水挥发而使得成球的粒径降低;反应时间在反应初期对成球粒径的影响很大,然后逐渐趋于平缓。经对煅烧前后产物的小角X射线衍射对比分析,发现煅烧后产物的峰强度增加,并且重叠峰向右漂移,指示表面活性剂分子从孔中移除并发生了孔径收缩现象,同时发现不同反应条件对产物的织构性质有一定的影响。研究了相关的反应机

  10. Multiple Resonances Induced by Plasmonic Coupling between Gold Nanoparticle Trimers and Hexagonal Assembly of Gold-Coated Polystyrene Microspheres.

    Science.gov (United States)

    Uchida, Takako; Yoshikawa, Takayasu; Tamura, Mamoru; Iida, Takuya; Imura, Kohei

    2016-09-15

    Optical properties of a gold nanoparticle trimer assembly coupled with gold-coated hexagonally close-packed polystyrene microspheres were investigated by linear and nonlinear spectroscopy. The observed reflection spectrum shows multiple peaks from the visible to near-infrared spectral regions. The spectroscopic properties were also examined by a finite-difference time-domain simulation. We found that the optical response of plasmons excited in the gold nanoparticle trimers was significantly modulated by strong coupling of the plasmons and the photonic mode induced in the gold-coated polystyrene assembly. Two-photon induced photoluminescence and Raman scattering from the sample were investigated, and both signals were significantly enhanced at the gold nanoparticle assembly. The simulations reveal that the electric fields can be enhanced site-selectively, not only at the interstitial sites in the nanoparticle assembly but also at the gaps between the particle and the gold film due to plasmonic interactions, by tuning the wavelength and are responsible for the strong optical responses.

  11. Ti(IV) carrying polydopamine-coated, monodisperse-porous SiO2 microspheres with stable magnetic properties for highly selective enrichment of phosphopeptides.

    Science.gov (United States)

    Salimi, Kouroush; Usta, Duygu Deniz; Çelikbıçak, Ömür; Pinar, Asli; Salih, Bekir; Tuncel, Ali

    2017-05-01

    A marked decrease in the saturation magnetization by the formation of functional shells around the magnetic core is an important disadvantage of magnetic core-shell nanoparticles. Another drawback of Ti(IV)-functionalized immobilized metal affinity chromatography (IMAC) sorbents is the acidic character of the binding medium used for Ti(4+) attachment onto composite magnetic nanoparticles, which causes an additional decrease in the saturation magnetization owing to the chemical interaction between the acidic moiety and the magnetic core. An IMAC sorbent in the form of magnetic microspheres with superior and stable magnetic properties with respect to magnetic core-shell nanoparticles was designed for phosphopeptide enrichment. Magnetic, monodisperse-porous silica microspheres (MagSiO2) 6μm in size were synthesized by a new staged-shape template hydrolysis-condensation protocol. A porous-silica shell layer was generated around the microspheres to protect the magnetic core from the acidic medium during Ti(4+) attachment (MagSiO2@SiO2). The MagSiO2@SiO2 microspheres were coated with a polydopamine shell (MagSiO2@SiO2@PDA) and Ti(4+) was attached onto the composite microspheres (MagSiO2@SiO2@PDA@Ti(IV)). Formation of the PDA layer and Ti(4+) attachment did not cause any significant decrease in the saturation magnetization. The platform exhibited excellent performance for phosphopeptide enrichment from the digests of phosphorylated proteins. Selectivity was investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The detection limit for phosphopeptide enrichment by the MagSiO2@SiO2@PDA@Ti(IV) microspheres from the tryptic digests of β-casein was 50 fmol/mL. Usability of the proposed magnetic sorbent with complex biological samples was demonstrated by successful enrichment of four phosphopeptides from human serum. The proposed sorbent showed stable performance over five repeated uses. Copyright © 2017 Elsevier B.V. All rights

  12. [Preparation and application of solid phase extraction packing of zirconia microsphere coated with sulfonated crosslinked polystyrene].

    Science.gov (United States)

    Shen, Shuchang; Liu, Yuhui; Xiao, Xiaoxing

    2013-08-01

    Zirconia microsphere was prepared by polymerization-induced colloid aggregation (PICA) method and carbon-carbon double bond was grafted onto its surface by titanic acid ester coupling reagent. Poly(styrene-divinylbenzene) was synthesized by free radical polymerization by using styrene, divinylbenzene and carbon-carbon double bond on the microsphere surface in solution system, so the polymer was coated on the microsphere surface. After the benzene ring of the polymer was sulfonated, the cation exchange packing for solid phase extraction (SPE) was obtained. The material was characterized by Fourier transform infrared spectroscopy, scanning electron microscope and X-ray energy dispersive spectroscopy. Three herbicides of mesotrione, atrazine and acetochlor in water were determined by the SPE cartridge coupled with high performance liquid chromatography (HPLC). In the range of 0.5 - 3.0 mg/L, the relationships between the peak areas and mass concentrations of mesotrione, atrazine and acetochlor were linear with the correlation coefficients of 0.9936, 0.9925, 0.9919, respectively. The limits of detection were 5.41, 6.72 and 13.4 microg/L for mesotrione, atrazine and acetochlor, respectively. The results showed that the zirconium dioxide microspheres coated with polymer have diameters in the range of about 6 to 8 microm, the SPE cartridges of which have high adsorption rate for the targets.

  13. Monodisperse raspberry-like multihollow polymer/Ag nanocomposite microspheres for rapid catalytic degradation of methylene blue.

    Science.gov (United States)

    Tian, Qiong; Yu, Xiaojing; Zhang, Lifeng; Yu, Demei

    2017-04-01

    Raspberry-like multihollow polymer microspheres were prepared by seeded swelling polymerization and decorated with silver nanoparticles (AgNPs) in the presence of polyvinylpyrrolidone (PVP) which acted as both reducing and stabilizing agent. Formation mechanism of the raspberry-like multihollow microsphere was discussed on the basis of water absorption of sulfonated groups in the seeded swelling polymerization. Effects of weight ratio of sodium 4-vinylbenzenesulfonate to styrene (NaSS/St) of the seed particles, the concentration of PVP and [Ag(NH3)2](+) ions on the properties of polymer/Ag nanocomposite microspheres were investigated by microscopic observation, nitrogen adsorption/desorption isotherms, UV-vis absorption spectra, X-ray diffraction patterns and thermogravimetric analysis. The results demonstrated that the raspberry-like multihollow microspheres were successfully fabricated by controlling over the NaSS/St of the seed particles in the seeded swelling polymerization by which the fabrication of hollow structure became simple and convenient. The spherical AgNPs were loaded on the polymer microsphere by in-situ chemical reduction due to the stabilization and reduction of PVP and the attraction between sulfonated groups and [Ag(NH3)2](+) ions. The raspberry-like multihollow polymer/Ag microspheres showed good catalytic activity and reusability in the degradation of methylene blue in the presence of NaBH4.

  14. The polystyrene microsphere filling with hydrogen isotopes through the fill tube with consequent freezing

    Science.gov (United States)

    Izgorodin, V. M.; Solomatina, E. Y.; Pepelyaev, A. P.; Rogozhina, M. A.; Osetrov, E. I.

    2016-09-01

    Process of spherical polystyrene capsules filling with hydrogen isotopes through the fill tube for the purpose of a cryogenic target building is described. The scheme of the stand for researches and a technique of carrying out of experiments is represented. Results of capsules filling and subsequent freezing for protium, deuterium and protium- deuterium mixture are shown.

  15. Evaporative purification to produce highly monodisperse polymers: Application to polystyrene for n =3 -13 and quantification of Tg from oligomer to polymer

    Science.gov (United States)

    Zhu, S.; Chai, Y.; Forrest, J. A.

    2017-07-01

    We demonstrate the use of selective thermal evaporation to separate and purify small molecular weight polymers into highly monodisperse polymers over an extended range of polymerization index. By exploiting the calculated dependence of polymer vapor pressure on polymerization index N and temperature T , we can isolate individual components (N -mers) of an initially polydisperse mixture. To demonstrate this ability, we consider polystyrene samples of Mw=600 g/mol and Mw=890 g/mol with narrow molecular weight distributions, as well as a Mw=1200 g/mol sample with a broader distribution. In each case we are able to separate the sample into milligram quantities of many different components. Using this technique, we have been able to isolate N -mers from 3 to 13. We use differential scanning calorimetry to measure the Tg values of these components, and find that the components have the same Tg values independent of the Mw or polydispersity of the sample they originate from. We find that even initially narrow molecular weight distributions have many different components whose Tg values can differ by more than 50 K. Calculations suggest the isolated components have Mw/Mn values less than 1.001 and through a second iteration of the process could become as low as 1.000 003. The measured Tg values for the N -mers as well as large N polymers are well described by a simple relation derived from the Fox equation for the Tg of mixtures.

  16. Novel ferroferric oxide/polystyrene/silver core-shell magnetic nanocomposite microspheres as regenerable substrates for surface-enhanced Raman scattering

    Science.gov (United States)

    Liu, Bo; Bai, Chong; Zhao, Dan; Liu, Wei-Liang; Ren, Man-Man; Liu, Qin-Ze; Yang, Zhi-Zhou; Wang, Xin-Qiang; Duan, Xiu-Lan

    2016-02-01

    A novel Ag-coated Fe3O4@Polystyrene core-shell microsphere has been designed via fabrication of Fe3O4@Polystyrene core-shell magnetic microsphere through a seed emulsion polymerization, followed by deposition of Ag nanoparticles using in-situ reduction method. Such magnetic microspheres can be utilized as sensitive surface-enhanced Raman scattering (SERS) substrates, using Rhodamine 6G (R6G) as a probe molecule, with both stable and reproducible performances. The SERS detection limit of R6G decreased to 1 × 10-10 M and the enhancement factor of this substrate on the order of 106 was obtained. In addition, owing to possessing excellent magnetic properties, the resultant microspheres could be separated rapidly by an external magnetic field and utilized repeatedly for three times at least. Therefore, the unique renewable property suggests a new route to eliminate the single-use problem of traditional SERS substrates and will be promising for the practical application.

  17. Sub-ppt Mass Spectrometric Detection of Therapeutic Drugs in Complex Biological Matrixes Using Polystyrene-Microsphere-Coated Paper Spray.

    Science.gov (United States)

    Wang, Teng; Zheng, Yajun; Wang, Xiaoting; Austin, Daniel E; Zhang, Zhiping

    2017-08-01

    Polystyrene (PS) is a class of polymer materials that offers great potential for various applications. However, the applications of PS microspheres in paper spray mass spectrometry are largely underexplored. Herein we prepared a series of PS microspheres via a simple dispersion polymerization and then used them as coating materials for paper spray mass spectrometry (MS) in high-sensitivity analysis of various therapeutic drugs in complex biological matrixes. In the preparation of PS-coated papers, the coating method was found playing a key role in determining the performance of the resulting paper substrate in addition to other parameters (e.g., starch type and amount, PS coating amount, and spray solvent). We also found that as a solvent was applied on PS-coated paper for paper spray, the analytes of interest would be first extracted out and then moved to the tip of paper triangle for spray along with the applied solvent. In the process, the surface energy of PS particles had a strong impact on the desorption performance of analytes from PS-coated paper substrate, and the PS with a high surface energy favored the elution of analytes to allow a high MS sensitivity. When the prepared PS coated paper was used as a substrate for paper spray, it gave high sensitivity in analysis of therapeutic drugs in various biological matrixes such as whole blood, serum, and urine with excellent repeatability and reproducibility. In contrast to uncoated filter paper, an improvement of 10-546-fold in sensitivity was achieved using PS-coated paper for paper spray, and an estimated lower limit of quantitation (LLOQs) in the range of 0.004-0.084 ng mL(-1) was obtained. The present study is significant in exploring the potential of PS for high-sensitivity MS analysis, and it provides a promising platform in the translation of the MS technique to clinical applications.

  18. UV-Vis and Surface Photovoltage Spectra of Fe2O3/Polystyrene Composite Microspheres

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Fe2O3 sol with the particle diameter of 3-5 nm was flocculated by the addition of SDS, and the flocculate formed was redispersed by the further addition of that surfactant. Thus the surfactant bilayer was formed on the surface of Fe2O3. The emulsion polymerization of styrene(St) adsolubilized on the surfactant adsorbed bilayer was carried out by initiator potassium persulfate(KPS). The UV-Vis and surface photovoltage spectra(SPS) indicate that the Fe2O3 particles were encapsulated in polystyrene(PSt) successfully.

  19. Size-dependent filtration of nanoparticles on porous films composed by polystyrene microsphere monolayers and applications in site-selective deposition of nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ruan, Weidong [Jilin University, State Key Laboratory of Supramolecular Structure and Materials (China); Zhou, Tieli [Changchun University, College of Food Engineering and Landscape Architecture (China); Sun, Chengbin; Tao, Yanchun; Lu, Fei; Wang, Xu; Zhao, Bing, E-mail: zhaob@mail.jlu.edu.cn [Jilin University, State Key Laboratory of Supramolecular Structure and Materials (China); Cui, Yinqiu, E-mail: cuiyq@jlu.edu.cn [Jilin University, School of Life Sciences (China)

    2015-10-15

    Composite films composed of polystyrene (PS) microsphere monolayers and gold (Au) and/or silver (Ag) nanoparticles (NPs) decorations were prepared by a novel size-dependent filtration effect on close-packed PS microsphere arrays. The uniform pores inlaid in the PS monolayer films acted as the transport tunnels for NPs. The steric restriction induced by the size of the pores was used as a main strategy to fabricate hybrid micro/nano films, which were composed of PS microspheres with inhomogeneous anisotropic decorations. The Au and Ag NPs were used as the building blocks to decorate the PS microspheres through a layer-by-layer self-assembly technique with the aid of polyelectrolyte coupling agents. Only the small particles which could pass through the micropores could reach to and deposit on the inner surfaces of the PS microsphere monolayer films. Large particles remained on the outside and could only deposit on the outer surfaces. Thus, the inhomogeneous anisotropic decoration was obtained. This study provides a novel strategy for fabricating anisotropic micro/nanostructures by the size-dependent filtration effect of NPs on porous films and has the potential in applications of anisotropic self-assembly, sensor, and surface modifications at nanoscale.

  20. Preparation of Highly Thermally Conductive Polymer Composite at Low Filler Content via a Self-Assembly Process between Polystyrene Microspheres and Boron Nitride Nanosheets.

    Science.gov (United States)

    Wang, Xiongwei; Wu, Peiyi

    2017-06-14

    Rational distribution and orientation of boron nitride nanosheets (BNNSs) are very significant for a polymer/BNNS composite to obtain a high thermal conductivity at low filler content. In this paper, a high-performance thermal interface material based on exfoliated BNNSs and polystyrene (PS) microspheres was fabricated by latex blending and subsequent compression molding. In this case, BNNSs and PS microspheres first self-assembled to form the complex microspheres via strong electrostatic interactions between them. The as-prepared complex microspheres were further hot-pressed around the glass transition temperature, which brought the selective distribution of BNNSs at the interface of the deformed PS microspheres. As a consequence, a polymer composite with homogeneous dispersion and high in-plane orientation of BNNSs in PS matrix was obtained. Benefitted from this unique structure, the resultant composite exhibits a significant thermal conductivity enhancement of 8.0 W m(-1) K(-1) at a low filler content of 13.4 vol %. This facile method provides a new strategy to design and fabricate highly thermally conductive composites.

  1. Microspheres

    Science.gov (United States)

    1990-01-01

    Vital information on a person's physical condition can be obtained by identifying and counting the population of T-cells and B-cells, lymphocytes of the same shape and size that help the immune system protect the body from the invasion of disease. The late Dr. Alan Rembaum developed a method for identifying the cells. The method involved tagging the T-cells and B-cells with microspheres of different fluorescent color. Microspheres, which have fluorescent dye embedded in them, are chemically treated so that they can link with antibodies. With the help of a complex antibody/antigen reaction, the microspheres bind themselves to specific 'targets,' in this case the T-cells or B-cells. Each group of cells can then be analyzed by a photoelectronic instrument at different wavelengths emitted by the fluorescent dyes. Same concept was applied to the separation of cancer cells from normal cells. Microspheres were also used to conduct many other research projects. Under a patent license Magsphere, Inc. is producing a wide spectrum of microspheres on a large scale and selling them worldwide for various applications.

  2. Rose-like monodisperse bismuth subcarbonate hierarchical hollow microspheres: One-pot template-free fabrication and excellent visible light photocatalytic activity and photochemical stability for NO removal in indoor air

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Fan [College of Environmental and Biological Engineering, Chongqing Technology and Business University, Chongqing, 400067 (China); Department of Civil and Structural Engineering, Research Center for Environmental Technology and Management, The Hong Kong Polytechnic University, Hong Kong (China); Department of Environmental Engineering, Zhejiang University, Hangzhou 310027 (China); Lee, S.C., E-mail: ceslee@polyu.edu.hk [Department of Civil and Structural Engineering, Research Center for Environmental Technology and Management, The Hong Kong Polytechnic University, Hong Kong (China); Wu, Zhongbiao [Department of Environmental Engineering, Zhejiang University, Hangzhou 310027 (China); Huang, Yu [Department of Civil and Structural Engineering, Research Center for Environmental Technology and Management, The Hong Kong Polytechnic University, Hong Kong (China); Fu, Min [College of Environmental and Biological Engineering, Chongqing Technology and Business University, Chongqing, 400067 (China); Ho, Wing-Kei [Nano and Advanced Materials Institute Limited, Hosted by The Hong Kong University of Science and Technology, Hong Kong (China); Zou, Shichun [School of Marine Sciences, Sun Yat-Sen University, Guangzhou, 510275 (China); Wang, Bo [Department of Civil and Structural Engineering, Research Center for Environmental Technology and Management, The Hong Kong Polytechnic University, Hong Kong (China)

    2011-11-15

    Graphical abstract: Rose-like monodisperse hierarchical nitrogen doped (BiO){sub 2}CO{sub 3} hollow microspheres fabricated by a one-pot template-free method exhibit excellent visible light photocatalytic activity and photochemical stability in the removal of NO in indoor air. The special hierarchical microstructure, the high charge separation efficiency and two-band-gap structure in all contribute to the outstanding photocatalytic performance. Highlights: {yields} Rose-like monodisperse hierarchical (BiO){sub 2}CO{sub 3} hollow microspheres are fabricated. {yields} The (BiO){sub 2}CO{sub 3} microspheres are self-assembled of single-crystalline nanosheets. {yields} Nitrogen is in situ doped into the lattice of hierarchical (BiO){sub 2}CO{sub 3} microspheres. {yields} The (BiO){sub 2}CO{sub 3} microspheres exhibit outstanding visible light activity for NO removal. {yields} The (BiO){sub 2}CO{sub 3} microspheres also exhibit high photochemical stability. - Abstract: Rose-like monodisperse hierarchical (BiO){sub 2}CO{sub 3} hollow microspheres are fabricated by a one-pot template-free method for the first time based on hydrothermal treatment of ammonia bismuth citrate and urea in water. The microstructure and band structure of the as-prepared (BiO){sub 2}CO{sub 3} superstructure are characterized in detail by X-ray diffraction, Raman spectroscopy, Fourier transform-infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, N{sub 2} adsorption-desorption isotherms, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy. The monodisperse hierarchical (BiO){sub 2}CO{sub 3} microspheres are constructed by the self-assembly of single-crystalline nanosheets. The aggregation of nanosheets result in the formation of three dimensional hierarchical framework containing mesopores and macropores, which is favorable for efficient transport of reaction molecules and harvesting of photo-energy. The result reveals the existence of

  3. Processing of Syndiotactic Polystyrene to Microspheres for Part Manufacturing through Selective Laser Sintering

    Directory of Open Access Journals (Sweden)

    Nicolas Mys

    2016-10-01

    Full Text Available Syndiotactic polystyrene pellets were processed into powder form using mechanical (ball milling, rotor milling and physicochemical (spray drying techniques with the intention of using it as feed material for selective laser sintering. New materials are an important component in broadening the application window for selective laser sintering but must meet strict requirements to be used. Particles obtained were characterized in size and shape using SEM imaging, analyzed by software, and compared to the product obtained by conventional ball milling. Rotor milling and spray drying proved capable of making spherical powders, yet only rotor milling achieved particles with a mean diameter within the desired range of 45–97 µm. Subsequently, the obtained powders were examined for the effect each processing technique imparts on the intrinsic properties of the material. Differential scanning calorimetry analysis revealed amorphization for all methods and a reduction in crystallinity after processing, however, the reduction in crystallinity was acceptably low for the spray-dried and rotor-milled powders. Ball milling displayed an exceptional reduction in crystallinity, suggesting severe degradation. As a final test, the rotor-milled powder was subjected to single-layer test and displayed good coalescence and smooth morphology, albeit with a large amount of warpage.

  4. Single-Beam Acoustic Trapping of Red Blood Cells and Polystyrene Microspheres in Flowing Red Blood Cell Saline and Plasma Suspensions.

    Science.gov (United States)

    Liu, Hsiao-Chuan; Li, Ying; Chen, Ruimin; Jung, Hayong; Shung, K Kirk

    2017-02-21

    Single-beam acoustic tweezers (SBATs) represent a new technology for particle and cell trapping. The advantages of SBATs are their deep penetration into tissues, reduction of tissue damage and ease of application to in vivo studies. The use of these tools for applications in drug delivery in vivo must meet the following conditions: large penetration depth, strong trapping force and tissue safety. A reasonable penetration depth for SBATs in the development of in vivo applications was established in a previous study conducted in water with zero velocity. However, capturing objects in flowing fluid can provide more meaningful results. In this study, we investigated the capability of SBATs to trap red blood cells (RBCs) and polystyrene microspheres in flowing RBC suspensions. Two different types of RBC suspension were prepared in this work: an RBC phosphate-buffered saline (PBS) suspension and an RBC plasma suspension. The results indicated that SBATs successfully trapped RBCs and polystyrene microspheres in a flowing RBC PBS suspension with an average steady velocity of 1.6 cm/s in a 2-mm-diameter polyimide. Furthermore, SBATs were found able to trap RBCs in a flowing RBC PBS suspension at speeds as high as 7.9 cm/s in a polyimide tube, which is higher than the velocity in capillaries (0.03 cm/s) and approaches the velocity in arterioles and venules. Moreover, the results also indicated that polystyrene microspheres can be trapped in an RBC plasma suspension, where aggregation is observed. This work represents a step forward in using this tool in actual in vivo experimentation.

  5. Preparation of Silver-Coated Polystyrene Composite Particles

    Institute of Scientific and Technical Information of China (English)

    陈卓; 詹鹏; 章建辉; 王振林; 章维益; 闵乃本

    2003-01-01

    We report a feasible approach to the preparation of monodispersed metal-shell composite microspheres based on a combination of surface reaction and surface seeding techniques. The method was implemented for coating polystyrene (PS) spheres with silver shell having a variable thickness by controlling the amount of reagents in the reaction procedure. These composite spherical particles in dimensions of the submicrometer range may become attractive building blocks for the creation of metallo-dielectric photonic band gap materials when they are organized into crystals.

  6. Computer Modeling Assisted Design of Monodisperse PLGA Microspheres with Controlled Porosity Affords Zero Order Release of an Encapsulated Macromolecule for 3 Months

    NARCIS (Netherlands)

    Kazazi-Hyseni, Filis; Landin, Mariana; Lathuile, Audrey; Veldhuis, Gert J.; Rahimian, Sima; Hennink, Wim E.; Kok, Robbert Jan; van Nostrum, Cornelus F.

    2014-01-01

    Purpose The aim of this study was the development of poly(D,L-lactide-co-glycolide) (PLGA) microspheres with controlled porosity, to obtain microspheres that afford continuous release of a macromolecular model compound (blue dextran). Methods PLGA microspheres with a size of around 40 μm and narrow

  7. Quantitative comparison of the autofluorescence of bacteria and polystyrene microspheres under violet wavelength excitation for verification of fluorescence-based bioaerosol detector results.

    Science.gov (United States)

    Hasegawa, Norio

    2013-01-01

    The autofluorescence intensity of bacteria and fungal spores was quantified by fluorescence microscopy in order to obtain the information for evaluating fluorescence-based bioaerosol detectors and was comparable to that of some types of polystyrene microspheres (PSMs). Although the intensity for microbes was distributed across a wide range over an order of magnitude in gray scale, it was in the intensity range of certain PSMs. Furthermore, some of those bacteria and PSMs were aerosolized in a test chamber and the fluorescence intensity was measured with a bioaerosol detector. Although there was a slight difference in the order of intensity from the results obtained by fluorescence microscopy, the fluorescence-based bioaerosol detector showed the intensity was in a comparable range.

  8. INTERACTION OF ANTIGEN AND ANTIBODY ON CORE-SHELL POLYMERIC MICROSPHERES

    Institute of Scientific and Technical Information of China (English)

    Gang Li; Qing-bin Meng; Zhan-yong Li; Ying-li An; Xiao-xia Zhu

    2011-01-01

    Monodispersed microspheres with polystyrene as the core and poly(acrylamide-co-N-acryloxysuccinimide) as the shell were synthesized by a two-step surfactant-free emulsion copolymerization. The core-shell morphology of the microspheres was shown by scanning electron microscopy and transmission electron microscopy. Rabbit immunoglobulin G (as antigen) was covalently coupled onto the microspheres by the reaction between succinimide-activated ester groups on the shell of the microspheres and amino groups of the antigen molecules. The size of particles was characterized by dynamic light scattering technique and was found to vary upon bioconjugation and interaction with proteins. The binding process was shown to be specific to goat anti-rabbit immunoglobulin G (as antibody) and reversible upon the addition of free antigen into the system.

  9. Rose-like monodisperse bismuth subcarbonate hierarchical hollow microspheres: one-pot template-free fabrication and excellent visible light photocatalytic activity and photochemical stability for NO removal in indoor air.

    Science.gov (United States)

    Dong, Fan; Lee, S C; Wu, Zhongbiao; Huang, Yu; Fu, Min; Ho, Wing-Kei; Zou, Shichun; Wang, Bo

    2011-11-15

    Rose-like monodisperse hierarchical (BiO)(2)CO(3) hollow microspheres are fabricated by a one-pot template-free method for the first time based on hydrothermal treatment of ammonia bismuth citrate and urea in water. The microstructure and band structure of the as-prepared (BiO)(2)CO(3) superstructure are characterized in detail by X-ray diffraction, Raman spectroscopy, Fourier transform-infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, N(2) adsorption-desorption isotherms, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy. The monodisperse hierarchical (BiO)(2)CO(3) microspheres are constructed by the self-assembly of single-crystalline nanosheets. The aggregation of nanosheets result in the formation of three dimensional hierarchical framework containing mesopores and macropores, which is favorable for efficient transport of reaction molecules and harvesting of photo-energy. The result reveals the existence of special two-band-gap structure (3.25 and 2.0 eV) for (BiO)(2)CO(3). The band gap of 3.25 eV is intrinsic and the formation of smaller band gap of 2.0 eV can be ascribed to the in situ doped nitrogen in lattice. The performance of hierarchical (BiO)(2)CO(3) microspheres as efficient photocatalyst are further demonstrated in the removal of NO in indoor air under both visible light and UV irradiation. It is found that the hierarchical (BiO)(2)CO(3) microspheres not only exhibit excellent photocatalytic activity but also high photochemical stability during long term photocatalytic reaction. The special microstructure, the high charge separation efficiency due to the inductive effect, and two-band-gap structure in all contribute to the outstanding photocatalytic activities. The discovery of monodisperse hierarchical nitrogen doped (BiO)(2)CO(3) hollow structure is significant because of its potential applications in environmental pollution control, solar energy conversion, catalysis and other related

  10. Immunocapture of CD133-positive cells from human cancer cell lines by using monodisperse magnetic poly(glycidyl methacrylate) microspheres containing amino groups

    Energy Technology Data Exchange (ETDEWEB)

    Kuan, Wei-Chih [Department of Chemical Engineering, Systems Biology and Tissue Engineering Research Center, National Chung Cheng University, Minhisung 621, Taiwan (China); Horák, Daniel, E-mail: horak@imc.cas.cz [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 162 06 Prague 6 (Czech Republic); Plichta, Zdeněk [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 162 06 Prague 6 (Czech Republic); Lee, Wen-Chien [Department of Chemical Engineering, Systems Biology and Tissue Engineering Research Center, National Chung Cheng University, Minhisung 621, Taiwan (China)

    2014-01-01

    Magnetic poly(glycidyl methacrylate)-based macroporous microspheres with an average particle size of 4.2 μm were prepared using a modified multi-step swelling polymerization method and by introducing amino functionality on their surfaces. Antibody molecules were oxidized on their carbohydrate moieties and bound to the amino-containing magnetic microspheres via a site-directed procedure. CD133-positive cells could be effectively captured from human cancer cell lines (HepG2, HCT116, MCF7, and IMR-32) by using magnetic microspheres conjugated to an anti-human CD133 antibody. After further culture, the immunocaptured CD133-expressing cells from IMR-32 proliferated and gradually detached from the magnetic microspheres. Flow-cytometric analysis confirmed the enrichment of CD133-expressing cells by using the antibody-bound magnetic microspheres. Such microspheres suitable for immunocapture are very promising for cancer diagnosis because the CD133-expressing cells in cancer cell lines have been suggested to be cancer stem cells. - Highlights: • Multi-step swelling polymerization produced poly(glycidyl methacrylate) microspheres. • Anti-human CD133 antibodies were bound to the amino-containing magnetic microspheres. • CD133-positive cells were effectively captured from human cancer cell lines. • Immunocaptured CD133-expressing cells proliferated and were detached from microspheres. • Enrichment of CD133-expressing cells was confirmed by flow-cytometric analysis.

  11. 膜乳化法制备尺寸均-P(NIPAM-co-AAc)微球及其羧基分布%Distribution of Carboxyl Groups in Monodispersed Poly(N-Isopropylacylamide-co-Acrylic Acid) Microspheres Prepared by Membrane Emulsification

    Institute of Scientific and Technical Information of China (English)

    司天保; 秦佳; 王玉霞; 马光辉

    2011-01-01

    Temperature-/pH-responsive monodispersed poly(N-isopropyl acrylamide-co-acrylic acid) [P(NIPAM-co-AAc)] microspheres were prepared by Shirasu porous glass membrane emulsification at room temperature with N,N,N',N'-tetramethylethylenediamine as accelerator and cyclohexane/trichluromethane mixture as oil phase. The monodispersed P(NIPAM-co-AAc) microspheres with controllable diameter could be reproducibly obtained with cyclohexane-trichloromethane mixture (volumetric ratio 7:3) as oil phase and two stage stirring speeds (140 and and 170 r/min) under the membrane emulsification pressure of 2 kPa. Conductometric titration was used to determine the distribution of carboxyl groups in the microspheres. Four-step titration curves of all the P(NIPAM-co-AAc)microspheres with different acrylic acid contents were obtained. With the increase of AAc content, the amounts of both exterior carboxyl and embeded carboxyl groups increased gradually, but the percentage of exterior carboxyl groups increased firstly, then remained at a fixed value. The highest percentage of exterior carboxyl groups was obtained with 15%(ω) acrylic acid in the microspheres.%采用膜乳化法,以环己烷和氯仿混合溶液为油相,在室温下通过加入加速剂TEMED引发聚合反应,制备了一系列不同内烯酸含量的P(NIPAM-co-AAc)微球.结果表明,在压力2 kPa、环己烷/氯仿体积比7:3、第一和第二阶段过膜搅拌速度分别为140和170 r/min的条件下,可制备粒径均一、大小可控、重复性较好的P(NlPAM-co-AAc)微球.用电导滴定法测定微球中羧基分布,所有不同丙烯酸含量的P(NIPAM-co-AAc)微球电导滴定曲线均为4阶梯形状,随其含量增加,微球外层羧基含量和内层包埋的羧基含量均逐渐增加,但外层羧基占总羧基含量比例先增大然后趋于不变,丙烯酸含量为15%时达最大值.

  12. Fabrication of polystyrene hollow microspheres as laser fusion targets by optimized density-matched emulsion technique and characterization

    Indian Academy of Sciences (India)

    K K Mishra; R K Khardekar; Rashmi Singh; H C Pant

    2002-07-01

    Inertial confinement fusion, frequently referred to as ICF, inertial fusion, or laser fusion, is a means of producing energy by imploding small hollow microspheres containing thermonuclear fusion fuel. Polymer microspheres, which are used as fuel containers, can be produced by solution-based micro-encapsulation technique better known as density-matched emulsion technique. The specifications of these microspheres are very rigorous, and various aspects of the emulsion hydrodynamics associated with their production are important in controlling the final product. This paper describes about the optimization of various parameters associated with density-matched emulsion method in order to improve the surface smoothness, wall thickness uniformity and sphericity of hollow polymer microspheres. These polymer microshells have been successfully fabricated in our lab, with 3–30 m wall thickness and 50–1600 m diameters. The sphericity and wall thickness uniformity are better than 99%. Elimination of vacuoles and high yield rate has been achieved by adopting the step-wise heating of W1/O/W2 emulsion for solvent removal.

  13. Preparation of Janus Graphene Oxide (GO) Nanosheets Based on Electrostatic Assembly of GO Nanosheets and Polystyrene Microspheres.

    Science.gov (United States)

    Yang, Yongfang; Zhang, Lei; Ji, Xiaotian; Zhang, Lixin; Wang, Hefang; Zhao, Hanying

    2016-09-01

    A facile and versatile method for the synthesis of Janus graphene oxide (GO) nanosheets with different structures is reported. Based on electrostatic assembly, Janus GO nanosheets can be easily functionalized with a template polymer or be defunctionalized by altering the ionic strength. By using this approach, Janus GO nanosheets are prepared successfully with hydrophobic polystyrene chains on one side and hydrophilic poly(2-(dimethylamino)ethyl methacrylate) chains on the other side.

  14. A reinforced composite structure composed of polydiacetylene assemblies deposited on polystyrene microspheres and its application to H5N1 virus detection

    Science.gov (United States)

    Dong, Wenjie; Luo, Jing; He, Hongxuan; Jiang, Long

    2013-01-01

    In this study, we immobilized polydiacetylene vesicles (PDAVs) onto the surface of polystyrene (PS) microspheres (1 μm in diameter) by using both electrical charge and conjugated forces to form a reinforced composite structure. These reinforced complexes could be easily washed, separated by centrifugation, and resuspended by gentle agitation. After passing through a narrow 200 μm-diameter channel, the composite structures maintained their original shape, demonstrating their resilience and potential for use in microfluidic technologies. The number of PDAVs in the composite structure could be mediated by changing the extent of layer deposition, which affected the sensitivity of detection. It showed that PDAVs did not change their blue color after addition of detecting probes such as anti-H5N1, which was of great importance in the fabrication and modification of stable color-changeable biosensors based on PDAVs. By conjugating anti-H5N1 antibodies to the PS@PDAV via N -hydroxysuccinimide and 1-ethyl3-(3-dimethylaminopropyl) carbodiimide chemistry, a stable blue complex, anti-H5N1 microsphere (PS@PDAV-anti-H5N1) was formed. A target antigen of H5N1 (HAQ [H5N1 strain A/ environment/Qinghai/1/2008{H5N1} in clade 0]) was detected by PS@PDAV-anti-H5N1. At an optimal PDAV deposition level of three layers, the limit of detection was determined to be approximately 3 0 ng/mL of HAQ by using optical spectrum measurement and visual inspection, meeting the needs of fast and simple color-changeable detection. However, a much lower limitation of detection (1 ng/mL) was able to be obtained using laser-scanning confocal microscopy, which could be compared with the results obtained with other sophisticated equipment. PMID:23403826

  15. A reinforced composite structure composed of polydiacetylene assemblies deposited on polystyrene microspheres and its application to H5N1 virus detection

    Directory of Open Access Journals (Sweden)

    Dong WJ

    2013-01-01

    Full Text Available Wenjie Dong,1 Jing Luo,2 Hongxuan He,2 Long Jiang11Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, People's Republic of China; 2National Research Center for Wildlife Born Diseases, Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of ChinaAbstract: In this study, we immobilized polydiacetylene vesicles (PDAVs onto the surface of polystyrene microspheres (1 µm in diameter by using both electrical charge and conjugated forces to form a reinforced composite structure. These reinforced complexes could be easily washed, separated by centrifugation, and resuspended by gentle agitation. After passing through a narrow 200 µm-diameter channel, the composite structures maintained their original shape, demonstrating their resilience and potential for use in microfluidic technologies. The number of PDAVs in the composite structure could be mediated by changing the extent of layer deposition, which affected the sensitivity of detection. It showed that PDAVs did not change their blue color after addition of detecting probes such as anti-H5N1, which was of great importance in the fabrication and modification of stable color-changeable biosensors based on PDAVs. By conjugating anti-H5N1 antibodies to the PS@PDAV via N-hydroxysuccinimide and 1-ethyl-3-(3-dimethylaminopropyl carbodiimide chemistry, a stable blue complex, anti-H5N1 microsphere (PS@PDAV-anti-H5N1 was formed. A target antigen of H5N1 (HAQ [H5N1 strain A/environment/Qinghai/1/2008{H5N1} in clade 0] was detected by PS@PDAV-anti-H5N1. At an optimal PDAV deposition level of three layers, the limit of detection was determined to be approximately 30 ng/mL of HAQ by using optical spectrum measurement and visual inspection, meeting the needs of fast and simple color-changeable detection. However, a much lower limitation of detection (1 ng/mL was able to be

  16. 聚苯乙烯微球的功能化修饰及其吸附拟除虫菊酯农药的性能评价%Functionalization of polystyrene microspheres and its adsorption properties to pyrethroid pesticides

    Institute of Scientific and Technical Information of China (English)

    贾珍珍; 李壹; 陆利霞; 熊晓辉

    2013-01-01

    Three kinds of polymer microspheres with different surface group,structure,length of the arm and polarity were modified with polystyrene microspheres and chloroacetyl polystyrene as the raw materials,and then charactered by infrared spectrometer and scanning electron microscopy.The results showed that the sphe-ricity,structure and form of polymer microspheres were well remained after modification.Finally,the adsorp-tion abilities of three kinds of polymer microspheres on pyrethroid pesticides were studied.The results showed that the adsorption abilities of the polymer microspheres after modified were better than the raw microspheres. The experimental results lay a theoretical foundation for the development of solid phase polymer extraction ma-terial of pesticide residues.%分别以聚苯乙烯微球和氯乙酰化聚苯乙烯为原料改性修饰了表面基团、臂长、结构功能各异的3种聚合物微球,并对修饰结果进行红外和扫描电镜分析。结果表明,修饰之后的微球依然保持较好的球形度、结构和形态均匀。研究了3种聚合物微球对拟除虫菊酯类农药的吸附能力。结果表明,改性之后的聚合物微球吸附能力优于原料微球。为农药残留聚合物固相萃取材料的开发奠定了理论基础。

  17. 光致变色多孔聚苯乙烯功能微球的制备和性能%Preparation of functionalized porous photochromic polystyrene microspheres and their performance

    Institute of Scientific and Technical Information of China (English)

    孙静; 裴广玲

    2011-01-01

    Porous cross-linked polystyrene microspheres were prepared by disperse polymerization in the presence of toluene/heptane as pore-forming agents.The effects of monomer, initiating agent, stabilizer, and cross-linker on the average size of the microspheres were investigated, and the photochromic performance of the porous polystyrene microspheres after adsorbing photochromic materials at ambient temperature and pressure was primarily evaluated.Results indicate that the porous polystyrene microspheres obtained under the optimized conditions have an average grain size of 1 μm.After adsorbing photochromic materials, the porous microspheres were able to rapidly reverse color under ultraviolet or sun light irradiation.Besides, the porous photochromic polystyrene microspheres could be fabricated into photochromic materials by using blending or coating technology; and it was feasible to improve their long lasting discoloring performance by surface-capping.%以甲苯/庚烷为致孔剂,利用分散聚合技术制备了多孔交联聚苯乙烯微球.研究了聚合单体、引发剂、稳定剂、交联剂等对微球平均粒径的影响,并初步评价了其在常温常压下吸附光致变色材料后的光致变色性能.结果表明,在最佳条件下制得的多孔聚合物微球平均粒径为1 μm;吸附光致变色材料后,其在紫外或日光照射下具有快速可逆的光致变色功能.利用共混或涂层技术可以将光致变色微球制备成光致变色材料;通过对变色微球进行表面包覆,可进一步提高其变色持久性.

  18. Thermo- and pH-responsive polymer brushes-grafted gigaporous polystyrene microspheres as a high-speed protein chromatography matrix.

    Science.gov (United States)

    Qu, Jian-Bo; Xu, Yu-Liang; Liu, Jun-Yi; Zeng, Jing-Bin; Chen, Yan-Li; Zhou, Wei-Qing; Liu, Jian-Guo

    2016-04-08

    Dual thermo- and pH-responsive chromatography has been proposed using poly(N-isopropylacrylamide-co-butyl methacrylate-co-N,N-dimethylaminopropyl acrylamide) (P(NIPAM-co-BMA-co-DMAPAAM)) brushes grafted gigaporous polystyrene microspheres (GPM) as matrix. Atom transfer radical polymerization (ATRP) initiator was first coupled onto GPM through Friedel-Crafts acylation with 2-bromoisobutyryl bromide. The dual-responsive polymer brushes were then grafted onto GPM via surface-initiated ATRP. The surface composition, gigaporous structure, protein adsorption and dual-responsive chromatographic properties of the matrix (GPM-P(NIPAM-co-BMA-co-DMAPAAM) were characterized in detail. Results showed that GPM were successfully grafted with thermoresponsive cationic polymer brushes and that the gigaporous structure was well maintained. A column packed with GPM-P(NIPAM-co-BMA-co-DMAPAAM presented low backpressure, good permeability and appreciable thermo-responsibility. By changing pH of the mobile phase and temperature of the column in turn, the column can separate three model proteins at the mobile phase velocity up to 2528cmh(-1). A separation mechanism of this matrix was also proposed. All results indicate that the dual thermo- and pH-responsive chromatography matrix has great potentials in 'green' high-speed protein chromatography.

  19. 单分散聚苯乙烯胶体颗粒的界面电性质研究%The Study of Monodisperse Polystyrene Microsphere’s interface electrical properties

    Institute of Scientific and Technical Information of China (English)

    刘丽; 严亚; 陈启明

    2007-01-01

      以过硫酸钾(KPS)为引发剂,以水为反应介质,采用无皂乳液聚合工艺,制备出粒径在500nm左右单分散(分散系数<5%)聚苯乙烯微球.所制备的聚苯乙烯微球为光滑的球形颗粒.研究发现;由无皂乳液聚合法制备的胶体颗粒其ζ电势在不同的离子强度下随pH的变化曲线均出现平台pH6~10.5,说明在一定的离子强度和pH条件下,聚苯乙烯胶乳的ζ电势具有良好的稳定性.聚苯乙烯胶乳有望作为具有一定电势值的标准颗粒.%  The water systems have been exploited as dispersion medium in soap-free polymerizing of polystyrene (PS) using potassium persulfate as an initiator.The size of particles is round 500nm(coefficient of variation<5%). The study on the curves of Zeta-potential (ζ) versus pH in different ionic strength showed that the polystyrene colloidal particles prepared by soap-free emulsion polymerization are rather stable theirζ-potential were invariable with the pH varied from 6 to 10.5, so the PS microspheres could be as a model particlesfor itsζ-potential value.

  20. Release and pharmacokinetics of near-infrared labeled albumin from monodisperse poly(D,L-lactic-co-hydroxymethyl glycolic acid) microspheres after subcapsular renal injection

    NARCIS (Netherlands)

    Kazazi-Hyseni, F.; Van Vuuren, S. H.; Van Der Giezen, D. M.; Pieters, E. H.; Ramazani, F.; Rodriguez, S.; Veldhuis, G. J.; Goldschmeding, R.; Van Nostrum, C. F.; Hennink, W. E.; Kok, R. J.

    2015-01-01

    Subcapsular renal injection is a novel administration method for local delivery of therapeutics for the treatment of kidney related diseases. The aim of this study was to investigate the feasibility of polymeric microspheres for sustained release of protein therapeutics in the kidney and study the s

  1. 单分散间苯二酚-甲醛气凝胶微球的制备工艺%Preparation of Monodisperse Resorcinol-formaldehyde Aerogel Microspheres

    Institute of Scientific and Technical Information of China (English)

    侯海乾; 王朝阳; 唐永建; 付志兵; 周莹

    2009-01-01

    采用T型微流体注射成型技术,以邻苯二甲酸二丁酯、液体石蜡和司班80为油相,间苯二酚/甲醛(RF)溶液为水相,经过溶胶-凝胶、溶剂交换、超临界干燥等过程制备了单分散RF气凝胶微球,并就制备过程中RF溶液与分散剂油相的选择、预聚时间、流速比、搅拌速率、固化温度等影响因素进行了初步讨论.当RF溶液质量分数为10%,60℃预聚1.5 h,间苯二酚与碳酸钠的物质的量之比为100,邻苯二甲酸二丁酯与液体石蜡的质量比为8:1,流速比控制在8~16,搅拌速率为65~90r/min,固化温度为35℃时,制备得到了RF乳液,其粒径分布系数小于2%.%Based on a novel T-shaped microfluidic device, monodisperse RF aerogel microspheres are prepared by using dibutyl phthalate,atoleine and span 80 as oil phase, RF solution as water phase, and by sol-gel, solvent exchanging and supercritical drying. The factors such as the choice of RF solution and oil, prepolymerization time, the flow rate ratio of oil to water phase, stirring rate and solidification temperature, which affect the process have been preliminarily discussed. When the polymerization reaction occur in the following conditions: RF solution is 10% ,prepolymerization time is 1. 5 hours at 60℃, the molar ratio of resorcinol to sodium carbonate is 100, the mass ratio of dibutyl phthalate to atoleine is 8,the flow rate ratio of oil to water phase is 8-16, stirring rate is 65~90r/min and solidification temperature is 35℃, the experiment has fabricated monodisperse RF aerogel microspheres, whose coefficient of variation (CV value) of all the RF droplets is below 2% .

  2. STRUCTURING OF DIAMOND FILMS USING MICROSPHERE LITHOGRAPHY

    Directory of Open Access Journals (Sweden)

    Mária Domonkos

    2014-10-01

    Full Text Available In this study, the structuring of micro- and nanocrystalline diamond thin films is demonstrated. The structuring of the diamond films is performed using the technique of microsphere lithography followed by reactive ion etching. Specifically, this paper presents a four-step fabrication process: diamond deposition (microwave plasma assisted chemical vapor deposition, mask preparation (by the standard Langmuir-Blodgett method, mask modification and diamond etching. A self-assembled monolayer of monodisperse polystyrene (PS microspheres with close-packed ordering is used as the primary template. Then the PS microspheres and the diamond films are processed in capacitively coupled radiofrequency plasma  using different plasma chemistries. This fabrication method illustrates the preparation of large arrays of periodic and homogeneous hillock-like structures. The surface morphology of processed diamond films is characterized by scanning electron microscopy and atomic force microscope. The potential applications of such diamond structures in various fields of nanotechnology are also briefly discussed.

  3. Preparation, Characterization of Monodisperse Polysiloxane Microspheres and Its Application as Light Scattering Agents%单分散聚硅氧烷微球的制备表征及作为光散射剂的应用

    Institute of Scientific and Technical Information of China (English)

    马文石; 张冬桥; 段宇; 万兆荣; 王洪; 徐迎宾

    2012-01-01

    以乳液聚合法制备粒径分布均匀、球形度良好的聚硅氧烷微球。采用扫描电镜(SEM)、动态光散射(DLS)、红外光谱(FT-IR)、X射线衍射(XRD)、热重分析(TGA)和接触角等测试技术对微球的微观形貌、粒径大小及分布、聚集态结构、耐热性、疏水性等进行了表征。将平均粒径为1.5μm的聚硅氧烷微球作为光散射剂添加到光学级聚甲基丙烯酸甲酯(PMMA)树脂中,可制备出性能优良的光散射材料。当聚硅氧烷微球添加质量分数约0.6%时,光散射材料的透光率是86.1%,雾度是91.25%,拉伸强度达到最大值77.2 MPa,弯曲强度是87.2 MPa,简支梁缺口冲击强度是2.16 kJ/m2,悬臂梁缺口冲击强度是2.71 kJ/m2,综合性能良好。%Highly uniform and monodisperse polysiloxane microspheres were prepared by emulsion polymeration.The morphology,size distribution,and state of aggregation were characterized by SEM,dynamic light scattering(DLS),FT-IR and XRD.The thermodecomposition and hydrophobicity of these microspheres were investigated with TGA and water contact angle measurement.Light scattering material with excellent performance could be prepared by blending polysiloxane microspheres(the average size of 1.5 μm) with optical-grade polymethylmethacylate(PMMA).When the mass fraction of microspheres is about 0.6%,the transmittance of composite material is 86.1% and the haze is 91.25%,the tensile strength reaches its maximum,namely 77.2 MPa,the bending strength is 87.2 MPa,the charpy notched impact strength is 2.16 kJ/m^2,the Izod notched impact strength is 2.71 kJ/m^2.The comprehensive properties of the composite material are excellent.

  4. Controllable assembly of well-defined monodisperse Au nanoparticles on hierarchical ZnO microspheres for enhanced visible-light-driven photocatalytic and antibacterial activity

    Science.gov (United States)

    Wang, Yuan; Fang, Hua-Bin; Zheng, Yan-Zhen; Ye, Rongqin; Tao, Xia; Chen, Jian-Feng

    2015-11-01

    A high-efficiency visible-light-driven photocatalyst composed of homogeneously distributed Au nanoparticles (AuNPs) well-defined on hierarchical ZnO microspheres (ZMS) via a controllable layer-by-layer self-assembly technique is demonstrated. The gradual growth of the characteristic absorption bands of Au loaded on ZnO in the visible light region with an increasing number of assemblies indicates the enhancement of the light harvesting ability of the ZMS/Au composites as well as the reproducibility and controllability of the entire assembly process. Results on the photoelectrochemical performance characterized by EIS and transient photocurrent response spectra indicate that the ZMS/Au composites possess increased photoinduced charge separation and transfer efficiency compared to the pure ZMS film. As a result, the hybrid composites exhibited enhanced decomposition activity for methylene blue and salicylic acid as well as antibacterial activity in killing S. aureus and E. coli under visible light irradiation. It can be noted that well-distributed Au components even at a rather low Au/ZnO weight ratio of ~1.2% also exhibited extraordinary photocatalysis. Such a facile and controllable self-assembly approach may be viable for preparing high-performance visible-light-driven ZMS/Au photocatalysts in a simple and controllable way, and consequently, the technology may extend to other plasmon-enhanced heterostructures made of nanostructured semiconductors and noble metals for great potential application in environmental protection.A high-efficiency visible-light-driven photocatalyst composed of homogeneously distributed Au nanoparticles (AuNPs) well-defined on hierarchical ZnO microspheres (ZMS) via a controllable layer-by-layer self-assembly technique is demonstrated. The gradual growth of the characteristic absorption bands of Au loaded on ZnO in the visible light region with an increasing number of assemblies indicates the enhancement of the light harvesting ability of

  5. Hybrid microspheres

    Science.gov (United States)

    Rembaum, Alan (Inventor); Yen, Richard C. K. (Inventor)

    1985-01-01

    Substrates, particularly inert synthetic organic resin beads (10) or sheet (12) such as polystyrene are coated with a covalently bound layer (24) of polyacrolein by irradiation a solution (14) of acrolein or other aldehyde with high intensity radiation. Individual microspheres (22) are formed which attach to the surface to form the aldehyde containing layer (24). The aldehyde groups can be converted to other functional groups by reaction with materials such as hydroxylamine. Adducts of proteins such as antibodies or enzymes can be formed by direct reaction with the surface aldehyde groups.

  6. Removals of cryptosporidium parvum oocysts and cryptosporidium-sized polystyrene microspheres from swimming pool water by diatomaceous earth filtration and perlite-sand filtration.

    Science.gov (United States)

    Lu, Ping; Amburgey, James E; Hill, Vincent R; Murphy, Jennifer L; Schneeberger, Chandra L; Arrowood, Michael J; Yuan, Tao

    2017-06-01

    Removal of Cryptosporidium-sized microspheres and Cryptosporidium parvum oocysts from swimming pools was investigated using diatomaceous earth (DE) precoat filtration and perlite-sand filtration. In pilot-scale experiments, microsphere removals of up to 2 log were obtained with 0.7 kg·DE/m(2) at a filtration rate of 5 m/h. A slightly higher microsphere removal (2.3 log) was obtained for these DE-precoated filters when the filtration rate was 3.6 m/h. Additionally, pilot-scale perlite-sand filters achieved greater than 2 log removal when at least 0.37 kg/m(2) of perlite was used compared to 0.1-0.4 log removal without perlite both at a surface loading rate of 37 m/h. Full-scale testing achieved 2.7 log of microspheres and oocysts removal when 0.7 kg·DE/m(2) was used at 3.6 m/h. Removals were significantly decreased by a 15-minute interruption of the flow (without any mechanical agitation) to the DE filter in pilot-scale studies, which was not observed in full-scale filters. Microsphere removals were 2.7 log by perlite-sand filtration in a full-scale swimming pool filter operated at 34 m/h with 0.5 kg/m(2) of perlite. The results demonstrate that either a DE precoat filter or a perlite-sand filter can improve the efficiency of removal of microspheres and oocysts from swimming pools over a standard sand filter under the conditions studied.

  7. Synthesis of novel porous magnetic silica microspheres as adsorbents for isolation of genomic DNA.

    Science.gov (United States)

    Zhang, Zhichao; Zhang, Liming; Chen, Lei; Chen, Ligong; Wan, Qian-Hong

    2006-01-01

    An improved procedure is described for preparation of novel mesoporous microspheres consisting of magnetic nanoparticles homogeneously dispersed in a silica matrix. The method is based on a three-step process, involving (i) formation of hematite/silica composite microspheres by urea-formaldehyde polymerization, (ii) calcination of the composite particles to remove the organic constituents, and (iii) in situ transformation of the iron oxide in the composites by hydrogen reductive reaction. The as-synthesized magnetite/silica composite microspheres were nearly monodisperse, mesoporous, and magnetizable, with as typical values an average diameter of 3.5 microm, a surface area of 250 m(2)/g, a pore size of 6.03 nm, and a saturation magnetization of 9.82 emu/g. These magnetic particles were tested as adsorbents for isolation of genomic DNA from Saccharomyces cerevisiae cells and maize kernels. The results are quite encouraging as the magnetic particle based protocols lead to the extraction of genomic DNA with satisfactory integrity, yield, and purity. Being hydrophilic in nature, the porous magnetic silica microspheres are considered a good alternative to polystyrene-based magnetic particles for use in biomedical applications where nonspecific adsorption of biomolecules is to be minimized.

  8. Spherical and polygonal shape of Au nanoparticles coated functionalized polymer microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ting; Li, Yingzhi; Zhang, Junxian; Qi, Yalong; Zhao, Xin; Zhang, Qinghua, E-mail: qhzhang@dhu.edu.cn

    2015-08-01

    Highlights: • PS/PPy with well-defined core/shell structures was prepared in aqueous solution. • Au NPs were coated on PS/PPy by the fixation and continuous growth process. • Mercapto-groups played a role in the number and morphology of Au shell. • PS/PPy/Au had homogeneous and dense Au coatings with different shape. - Abstract: Uniform polystyrene (PS)/polypyrrole (PPy) composite microspheres with well-defined core/shell structures are synthesized by chemical oxidative polymerization. Gold nanoparticles (Au NPs) are successfully coated on the surface of PS/PPy microspheres by means of electrostatic interactions due to the functionalized PPy coatings supplying sufficient amino groups and the additive of mercapto acetic acid. Furthermore, the as-prepared PS/PPy/Au microspheres serving as seeds facilitate Au NPs further growth by in situ reduction in HAuCl{sub 4} solution to obtain PS/PPy/Au spheres with the core/shell/shell structure. Morphology observation demonstrates that the monodisperse PS/PPy/Au microspheres compose of uniform cores and the compact coatings containing distinct two layers. X-ray diffraction and X-ray photoelectron spectroscope confirm the existence of PPy and Au on the surface of the composite spheres. This facile approach to preparing metal-coated polymer spheres supplies the potential applications in biosensors, electronics and medical diagnosis.

  9. Polymeric microspheres

    Science.gov (United States)

    Walt, David R.; Mandal, Tarun K.; Fleming, Michael S.

    2004-04-13

    The invention features core-shell microsphere compositions, hollow polymeric microspheres, and methods for making the microspheres. The microspheres are characterized as having a polymeric shell with consistent shell thickness.

  10. Researching on microwave synthesize of SiO2 aerogels core/polystyrene shell microsphere%微波合成 Si O2气凝胶核/聚苯乙烯壳微球研究

    Institute of Scientific and Technical Information of China (English)

    刘新军; 朱原; 刘斌; 耿刚强

    2014-01-01

    将水玻璃为硅源所制备的纳米孔硅气凝胶与苯乙烯单体用微波加热合成法制备出SiO2气凝胶核/聚苯乙烯壳复合微球.用顺序间隔取样测试方法试验复合微球的密度、转化率和包覆率与微波合成温度、时间和聚合体系各组分变化情况,分析讨论了影响变化因素和原因.通过T EM 和FE-SEM 对复合微球进行结构与形貌表征.结果表明,优选体系组分配比为SiO2气凝胶3 g、苯乙烯21 g、乙醇水溶剂配比为380 g∶20 g、引发剂4.2 g及稳定剂2 g ,微波合成工艺参数为加热功率500 W ,加热时间40 m in、加热温度60℃.在此工艺条件下合成,复合微球合成转化率是67.1%、包覆率为32.7%,制备出的核壳结构复合微球的粒径约为100~200 nm、震实密度为0.353 g/cm3,且表面凹凸不平状似“草莓”的微粒.%The water glass as silicon source of the nanoporous silica aerogel with styrene mon-omer by microwave heating were prepared from SiO2 aerogel nuclear/polystyrene shell com-posite microspheres .Using sequential interval method to test the density of the composite microsphere ,conversion rate and encapsulation with the change of microwave synthesis tem-perature ,time and the component of polymer system .Analyzes and discusses the factors and reasons of the change .Characterize the structure and morphology of the composite micro-sphere through TEM and FE-SEM .The results show that the system is preferred ratio of SiO2 airgel group assignment 3 g ,styrene 21 g ,ethanol aqueous solvent ratio of 380 g∶20 g , initiator 4 .2 g and stabilizer 2 g ,microwave synthesis process parameters heating power 500 W ,heating time 40 min ,the heating temperature 60 ℃ .Synthesis under these conditions , the composite microspheres synthesis conversion rate is 67 .1% ,covering rate is 32 .7% ,core-shell composite microspheres prepared by the particle size of about 100~200 nm ,jolt density is 0

  11. Photoassisted Fenton degradation of polystyrene.

    Science.gov (United States)

    Feng, Hui-Min; Zheng, Jia-Chuan; Lei, Ngai-Yu; Yu, Lei; Kong, Karen Hoi-Kuan; Yu, Han-Qing; Lau, Tai-Chu; Lam, Michael H W

    2011-01-15

    Fenton and photoassisted Fenton degradation of ordinary hydrophobic cross-linked polystyrene microspheres and sulfonated polystyrene beads (DOWEX 50WX8) have been attempted. While the Fenton process was not able to degrade these polystyrene materials, photoassisted Fenton reaction (mediated by broad-band UV irradiation from a 250 W Hg(Xe) light source) was found to be efficient in mineralizing cross-linked sulfonated polystyrene materials. The optimal loadings of the Fe(III) catalyst and the H(2)O(2) oxidant for such a photoassisted Fenton degradation were found to be 42 μmol-Fe(III) and 14.1 mmol-H(2)O(2) per gram of the sulfonated polystyrene material. The initial pH for the degradation was set at pH 2.0. This photoassisted Fenton degradation process was also able to mineralize commonly encountered polystyrene wastes. After a simple sulfonation pretreatment, a mineralization efficiency of >99% (by net polymer weight) was achieved within 250 min. The mechanism of this advanced oxidative degradation process was investigated. Sulfonate groups introduced to the surface of the treated polystyrene polymer chains were capable of rapidly binding the cationic Fe(III) catalyst, probably via a cation-exchange mechanism. Such a sorption of the photoassisted Fenton catalyst was crucial to the heterogeneous degradation process.

  12. Uniaxial Elongational viscosity of bidisperse polystyrene melts

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.; Hassager, Ole

    2006-01-01

    The startup and steady uniaxial elongational viscosity have been measured for three bidisperse polystyrene (PS) melts, consisting of blends of monodisperse PS with molecular weights of 52 kg/mole or 103 kg/mole and 390 kg/mole. The bidisperse melts have a maximum in the steady elongational...

  13. Uniaxial Elongational viscosity of bidisperse polystyrene melts

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.; Hassager, Ole

    2006-01-01

    The startup and steady uniaxial elongational viscosity have been measured for three bidisperse polystyrene (PS) melts, consisting of blends of monodisperse PS with molecular weights of 52 kg/mole or 103 kg/mole and 390 kg/mole. The bidisperse melts have a maximum in the steady elongational viscos...

  14. Preparation of molecularly imprinted microspheres by photo-grafting on supports modified with iniferter

    Institute of Scientific and Technical Information of China (English)

    RONG Fei; FENG Xiaogang; LI Ping; YUAN Chunwei; FU Degang

    2006-01-01

    Molecularly imprinted microspheres (MIMs) of D-mandelic acid were synthesized in this study. Chloromethylated polystyrene beads modified with iniferter were used as supports for photo-grafting of a molecularly imprinted polymer (MIP) layer. The polymers were characterized by FT-IR, elemental analysis and thermo-gravimetric analysis to testify the polymer formation and its thermal stability. Scanning electron micrographs (SEM) show that the MIP particles are mono-dispersed and well-spherical, with the average diameter of 4.38 μm and size distribution coefficient of 1.02. Furthermore, the MIMs were packed in a stainless steel column and evaluated as stationary phases in high performance liquid chromatography (HPLC). The prepared MIP exhibited a considerable capability of chiral separation between template and its enantiomer. Accordingly, this kind of MIP is likely to have wide applications in chemical sensing, chromatographic analysis and solid phase extraction.

  15. Photonic crystal heterostructures fabricated by TiO2 and ZnO inverse opals using colloidal crystal template with single kind of microspheres

    Science.gov (United States)

    Zhang, Yongna; Fu, Ming; Wang, Jigang; He, Dawei; Wang, Yongsheng

    2012-09-01

    The fabrication of photonic crystal heterostructures is important for the applications in the fields of integrated photonic crystal chips, multi-frequency optical Bragg filters or mirrors. However, multiple steps of self-assembly process of microspheres are always employed in the fabrication of photonic crystal heterostructures, which may produce lattice mismatches of colloidal crystals. Therefore, photonic crystal heterostructures fabricated by using colloidal crystal template with single kind of microspheres were investigated in this paper. A colloidal crystal template with uniform periodicity was firstly formed by monodispersed polystyrene microsphere. Then ZnO was electrodeposited into the interstices of the template. The thickness of ZnO was controlled to be less than the thickness of the template by varying the deposition time. After the TiO2 precursor was filled into the top voids in the template, the polystyrene colloidal crystal template was removed and photonic crystal heterostructures fabricated by ZnO and TiO2 were formed. Both the dielectric constant and the periodicity of the two parts of the heterostructures are different due to the shrinkage of the sol-gel process. The ZnO/TiO2 heterostructures have a broad photonic stop band which is the superposition of photonic stop bands of ZnO inverse opals and TiO2 inverse opals.

  16. Pickering乳液聚合制备聚苯乙烯/纳米SiO2复合微球与其性质%Properties of Polystyrene/Nano-SiO2 Composite Microspheres Prepared by Picketing Emulsion Polymerization

    Institute of Scientific and Technical Information of China (English)

    张卫红; 范晓东; 田威; 黄怡

    2012-01-01

    Stable Pickering emulsion was fabricated using amphiphilic nano-SiO2 particles as stabilizer.Then,two kinds of polystyrene/nano-SiO2(PS/SiO2) composite microspheres,which had different size and different morphology,were synthesized with oil-soluble azobisisobutyronitrile(AIBN) and water-soluble ammonium persulfate(APS) as initiator respectively.The possible mechanisms of Pickering emulsion polymerization initiated by different initiator were discussed.The product was characterized by means of FT-IR,multi angle laser light scattering photometer(GPC-MALLS),TGA and DSC.When AIBN was used as the initiator,the diameters of the microspheres were micron-sized(0.5 μm~2.0 μm).While the sub-micron-sized(0.1 μm~0.5 μm) microspheres were obtained by using APS as the initiator.And the weight-average molecular weight(w) of two kinds of polymer is 4.780×104 g/mol and 3.411×105 g/mol,respectively.The results of TGA and DSC indicated that the thermal properties of composite were elevated duo to the existence of nano-SiO2.%以两亲性纳米SiO2为稳定剂构筑Pickering乳液,分别采用偶氮二异丁腈(AIBN)及过硫酸铵(APS)作为引发剂引发苯乙烯单体聚合,制得了不同尺寸及形貌的聚苯乙烯/纳米SiO2(PS/SiO2)复合微球,并分析了Pickering乳液聚合的机理。通过傅里叶变换红外光谱仪(FT-IR)、凝胶渗透色谱-多角度激光光散射联用仪(GPC-MALLS)、热失重分析(TGA)及差示扫描量热仪(DSC)对产物进行了表征,结果表明,AIBN引发所得复合微球为微米级(0.5μm~2.0μm),而APS引发产物为亚微米级(0.1μm~0.5μm),两者引发所得聚合物重均分子量(-Mw)分别为4.780×10^4g/mol及3.411×10^5g/mol;复合微球的热性能因纳米SiO2的存在而得到增强。

  17. A constitutive analysis of transient and steady-state elongational viscosities of bidisperse polystyrene blends

    DEFF Research Database (Denmark)

    Wagner, Manfred H.; Rolon-Garrido, Victor H.; Nielsen, Jens Kromann

    2008-01-01

    The transient and steady-state elongational viscosity data of three bidisperse polystyrene blends were investigated recently by Nielsen et al. [J. Rheol. 50, 453-476 (2006)]. The blends contain a monodisperse high molar mass component (M-L= 390 kg/ mol) in a matrix of a monodisperse small molar m...

  18. Acrolein Microspheres Are Bonded To Large-Area Substrates

    Science.gov (United States)

    Rembaum, Alan; Yen, Richard C. K.

    1988-01-01

    Reactive cross-linked microspheres produced under influence of ionizing radiation in aqueous solutions of unsaturated aldehydes, such as acrolein, with sodium dodecyl sulfate. Diameters of spheres depend on concentrations of ingredients. If polystyrene, polymethylmethacrylate, or polypropylene object immersed in solution during irradiation, microspheres become attached to surface. Resulting modified surface has grainy coating with reactivity similar to free microspheres. Aldehyde-substituted-functional microspheres react under mild conditions with number of organic reagents and with most proteins. Microsphere-coated macrospheres or films used to immobilize high concentrations of proteins, enzymes, hormones, viruses, cells, and large number of organic compounds. Applications include separation techniques, clinical diagnostic tests, catalytic processes, and battery separators.

  19. Optical trapping of coated microspheres.

    Science.gov (United States)

    Bormuth, Volker; Jannasch, Anita; Ander, Marcel; van Kats, Carlos M; van Blaaderen, Alfons; Howard, Jonathon; Schäffer, Erik

    2008-09-01

    In an optical trap, micron-sized dielectric particles are held by a tightly focused laser beam. The optical force on the particle is composed of an attractive gradient force and a destabilizing scattering force. We hypothesized that using anti-reflection-coated microspheres would reduce scattering and lead to stronger trapping. We found that homogeneous silica and polystyrene microspheres had a sharp maximum trap stiffness at a diameter of around 800 nm--the trapping laser wavelength in water--and that a silica coating on a polystyrene microsphere was a substantial improvement for larger diameters. In addition, we noticed that homogeneous spheres of a correct size demonstrated anti-reflective properties. Our results quantitatively agreed with Mie scattering calculations and serve as a proof of principle. We used a DNA stretching experiment to confirm the large linear range in detection and force of the coated microspheres and performed a high-force motor protein assay. These measurements show that the surfaces of the coated microspheres are compatible with biophysical assays.

  20. Synthesis of Micron-size Functional Polystyrene Fluorescent Micro- spheres and their Adsorbability to Human Serum Albumin

    Institute of Scientific and Technical Information of China (English)

    Di Qiang WANG; He LI; Jie HU; Xian Feng LIAO; Bai Ling LIU

    2004-01-01

    Polystyrene microspheres with sulfo- or aldehyde- surface were synthesized through dispersion polymerization. Functional polystyrene fluorescent microspheres were prepared by the way of adding 2, 5-diphenyloxazole (PPO) into the reaction system directly and dying the blank microspheres in the ethanol solution of PPO. The influence of preparing matters on the encapsulating rate of PPO, and the influence of functional groups on the adsorbability to human serum albumin (HSA) were investigated.

  1. Sub-micron-sized polyethylenimine-modified polystyrene/Fe3O4/chitosan magnetic composites for the efficient and recyclable adsorption of Cu(II) ions

    Science.gov (United States)

    Xiao, Changwei; Liu, Xijian; Mao, Shimin; Zhang, Lijuan; Lu, Jie

    2017-02-01

    A sub-micron-sized polyethylenimine(PEI)-modified polystyrene/Fe3O4/chitosan magnetic composite (PS/Fe3O4/CS-PEI) was developed as a novel adsorbent for the removal of Cu(II) ions from aqueous solutions. The PS/Fe3O4/CS-PEI microspheres with a diameter of ∼300 nm can be highly monodisperse and conveniently separated from suspensions by a magnet due to their excellent magnetism. When the PS/Fe3O4/CS-PEI microspheres were used as an absorbent for the absorption of Cu(II) ions, the adsorption isotherms and adsorption kinetics well fitted the Langmuir model and the pseudo-second-order model, respectively. The maximum adsorption capacity was about 204.6 mg g-1, which was higher than those of other chitosan adsorbents reported recently. The adsorption was considerably fast, reaching the equilibrium within 15 min. In addition, the adsorbed Cu(II) ions could be effectively desorbed using 0.1 mol L-1 NaOH solution, and the regeneration study proved that the composite microspheres could be repeatedly utilized without significant capacity loss after six cycles. All the results demonstrated that the synthesized sub-micron-sized magnetic PS/Fe3O4/CS-PEI composites can be used as an ideal adsorbent of Cu(II) ions for environmental cleanup applications.

  2. Facile and Scalable Synthesis of Monodispersed Spherical Capsules with a Mesoporous Shell

    KAUST Repository

    Qi, Genggeng

    2010-05-11

    Monodispersed HMSs with tunable particle size and shell thickness were successfully synthesized using relatively concentrated polystyrene latex templates and a silica precursor in a weakly basic ethanol/water mixture. The particle size of the capsules can vary from 100 nm to micrometers. These highly engineered monodispersed capsules synthesized by a facile and scalable process may find applications in drug delivery, catalysis, separationm or as biological and chemical microreactors. © 2010 American Chemical Society.

  3. Polystyrene Prints

    Science.gov (United States)

    O'Malley, William

    1969-01-01

    Discussed are the exciting advantages and possibilities of using polystyrene trays found in meat packaging for printmaking. Among them are ease of use, low cost and quick availability of materials, beautiful textural effects. Procedures are explained for various age levels. (BF)

  4. Engineered monodisperse mesoporous materials

    Energy Technology Data Exchange (ETDEWEB)

    Saunders, R.S.; Small, J.H.; Lagasse, R.R.; Schroeder, J.L.; Jamison, G.M.

    1997-08-01

    Porous materials technology has developed products with a wide variety of pore sizes ranging from 1 angstrom to 100`s of microns and beyond. Beyond 15{angstrom} it becomes difficult to obtain well ordered, monodisperse pores. In this report the authors describe efforts in making novel porous material having monodisperse, controllable pore sizes spanning the mesoporous range (20--500 {angstrom}). They set forth to achieve this by using unique properties associated with block copolymers--two linear homopolymers attached at their ends. Block copolymers phase separate into monodisperse mesophases. They desired to selectively remove one of the phases and leave the other behind, giving the uniform monodisperse pores. To try to achieve this the authors used ring-opening metathesis polymerization to make the block copolymers. They synthesized a wide variety of monomers and surveyed their polymers by TGA, with the idea that one phase could be made thermally labile while the other phase would be thermally stable. In the precipitated and sol-gel processed materials, they determined by porosimetry measurements that micropores, mesopores, and macropores were created. In the film processed sample there was not much porosity present. They moved to a new system that required much lower thermal treatments to thermally remove over 90% of the labile phase. Film casting followed by thermal treatment and solvent extraction produced the desired monodisperse materials (based solely on SEM results). Modeling using Density Functional Theory was also incorporated into this project. The modeling was able to predict accurately the domain size and spacing vs. molecular weight for a model system, as well as accurate interfacial thicknesses.

  5. Spectrally resolved resonant propulsion of dielectric microspheres

    CERN Document Server

    Li, Yangcheng; Limberopoulos, Nicholaos I; Urbas, Augustine M; Astratov, Vasily N

    2015-01-01

    Use of resonant light forces opens up a unique approach to high-volume sorting of microspherical resonators with much higher uniformity of resonances compared to that in coupled-cavity structures obtained by the best semiconductor technologies. In this work, the spectral response of the propulsion forces exerted on polystyrene microspheres near tapered microfibers is directly observed. The measurements are based on the control of the detuning between the tunable laser and internal resonances in each sphere with accuracy higher than the width of the resonances. The measured spectral shape of the propulsion forces correlates well with the whispering-gallery mode resonances in the microspheres. The existence of a stable radial trap for the microspheres propelled along the taper is demonstrated. The giant force peaks observed for 20-{\\mu}m spheres are found to be in a good agreement with a model calculation demonstrating an efficient use of the light momentum for propelling the microspheres.

  6. Raspberry-like PS/CdTe/Silica Microspheres for Fluorescent Superhydrophobic Materials

    Science.gov (United States)

    Chang, Jinghui; Zang, Linlin; Wang, Cheng; Sun, Liguo; Chang, Qing

    2016-02-01

    Superhydrophobic particulate films were fabricated via deposition of raspberry-like fluorescent PS/CdTe/silica microspheres on clean glass substrates and surface modification. Particularly, the fluorescent microspheres were prepared by a kind of modified strategy, namely introducing poly (acrylic acid)-functionalized polystyrene microspheres and thiol-stabilized CdTe quantum dots into a hydrolysis reaction of tetraethoxysilane simultaneously. And through adjusting the reaction parameters, the polystyrene spheres with two particle sizes and three colors of CdTe quantum dots aqueous solution were obtained. Consequently, raspberry-like microspheres consist of polystyrene cores and the composite shells of CdTe quantum dots and silica. These microspheres possess a fluorescent characteristic and form a hierarchical dual roughness which was conductive to superhydrophobicity, and the hydrophobic tests also showed the contact angles of water droplets on the surface of the raspberry-like microspheres which were over 160° at room temperature.

  7. Raspberry-like PS/CdTe/Silica Microspheres for Fluorescent Superhydrophobic Materials.

    Science.gov (United States)

    Chang, Jinghui; Zang, Linlin; Wang, Cheng; Sun, Liguo; Chang, Qing

    2016-12-01

    Superhydrophobic particulate films were fabricated via deposition of raspberry-like fluorescent PS/CdTe/silica microspheres on clean glass substrates and surface modification. Particularly, the fluorescent microspheres were prepared by a kind of modified strategy, namely introducing poly (acrylic acid)-functionalized polystyrene microspheres and thiol-stabilized CdTe quantum dots into a hydrolysis reaction of tetraethoxysilane simultaneously. And through adjusting the reaction parameters, the polystyrene spheres with two particle sizes and three colors of CdTe quantum dots aqueous solution were obtained. Consequently, raspberry-like microspheres consist of polystyrene cores and the composite shells of CdTe quantum dots and silica. These microspheres possess a fluorescent characteristic and form a hierarchical dual roughness which was conductive to superhydrophobicity, and the hydrophobic tests also showed the contact angles of water droplets on the surface of the raspberry-like microspheres which were over 160° at room temperature.

  8. Preparation of Micron-size Functional Fluorescent Microspheres

    Institute of Scientific and Technical Information of China (English)

    WANG Di-qiang; LIU Bai-ling; LI He; HU Jie

    2004-01-01

    As a kind of special functional microspheres, fluorescent polymer microspheres could be used in cell label and separation, blood flow assay, flow cytometer marking, chemical reaction assay,and in analyst of the transform and diffusion of particles in soil 1. However, one of the most important applications of fluorescent microspheres is in the high-throughput screening of drugs (HTS) 2. Through affinity interaction, radioactive ligands (latent drugs) are bound to fluorescent microspheres covered by receptor, and luminescence is produced by radioactivity, so ligands can be assayed and screened.In this study, we developed a technique for preparing micron-size fluorescent microspheres with different functional groups. The methods included the synthesis of micron-size polystyrene microspheres through the dispersion polymerization of styrene in different media such as ethanol,ethanol-water, and isopropanol; the functional polystyrene microspheres were prepared by introduction of functional monomers into the reaction system of styrene; the functional fluorescent microspheres were obtained by the way of dying functional microspheres in the fluorescent material's ethanol solvent.The average diameter of microspheres was in the range of 1~10 μm, and the distribution was normal distribution. The functional groups included -OH, -CHO, -COOH, -CONH2, and SO3H. The absorbing spectrum and exciting spectrum were tested, the results showed that the maximal absorbance of fluorescent microsphere was near 306.5 nm, and its maximal excitation was near 362 nm. The excitation spectrum of fluorescent material (DPO) and fluorescent microspheres were shown in figure 1, and it indicated that the developed fluorescent microspheres showed the same excitation behavior like DPO, which related to the fluorescent microspheres had stable luminescence property.

  9. A review of recent progress in preparation of hollow polymer microspheres

    Institute of Scientific and Technical Information of China (English)

    Wei Bin; Wang Shujun; Song Hongguang; Liu Hongyan; Li Jie; Liu Ning

    2009-01-01

    The preparation methods of hollow polymer microspheres both at home and abroad are summarized, and their preparation mechanisms and developmental states are presented. These methods include the liquid droplet method, dried-gel droplet method, self-assembly method, microencapsulation method, emulsion polymerization method and the template method. Hollow polystyrene microspheres are the most extensively studied in the research of hollow polymer microspheres. Through comparison of the advantages and disadvantages of different preparation methods, it is concluded that microencapsulation method is most suitable for preparing polystyrene hollow microspheres.

  10. Molecularly imprinted shells from polymer and xerogel matrices on polystyrene colloidal spheres.

    Science.gov (United States)

    Guan, Guijian; Liu, Renyong; Mei, Qingsong; Zhang, Zhongping

    2012-04-10

    We have devised a facile and general methodology for the synthesis of various molecularly imprinted shells at the surface of polystyrene (PS) colloidal spheres to recognize the explosive compound 2,4,6-trinitrotoluene (TNT). PS spheres with surface-functionalized carboxyl-group layers could direct a selective imprinting polymerization on their surface through the hydrogen-bonding interactions between surface carboxyl groups and amino monomers. Meanwhile, homogeneous polymerization in the solution phase was completely prevented by stepwise polymerization. The overall process led to the formation of monodisperse molecularly imprinted core-shell microspheres, and was very successful in the preparation of organic polymer and inorganic xerogel shells. Furthermore, greater capacity and faster binding kinetics towards target species were achieved, because surface-imprinted sites ensured the complete removal of templates, good accessibility to target molecules, and low mass-transfer resistance. The results reported herein, concerning the production of high-quality molecularly imprinted products, could also form the basis for the formulation of a new strategy for the fabrication of various functional coating layers on colloidal spheres with potential applications in the fields of separations and chemical sensing.

  11. Optical properties of metallo-dielectric microspheres in opal structures

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Y; Whitehouse, C; Li, Jensen; Tam, Wing Yim; Chan, C T; Sheng Ping [Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)

    2003-09-03

    We report the fabrication of opal structure using metallo-dielectric silica microspheres. Mono-dispersed silica microspheres were coated with silver using an electrode-less wet-plating technique. Thin slabs of opal were obtained by assembling the silver-coated microspheres between two glass plates using a forced-packing method. The optical properties of the resulting opal structure were studied in the infrared range. Good agreement is obtained with the predictions of a multiple scattering approach, provided that the silver layer is modelled as a silver composite.

  12. Oyster reproduction is affected by exposure to polystyrene microplastics

    National Research Council Canada - National Science Library

    Rossana Sussarellu; Marc Suquet; Yoann Thomas; Christophe Lambert; Caroline Fabioux; Marie Eve Julie Pernet; Nelly Le Goïc; Virgile Quillien; Christian Mingant; Yanouk Epelboin; Charlotte Corporeau; Julien Guyomarch; Johan Robbens; Ika Paul-Pont; Philippe Soudant; Arnaud Huvet

    2016-01-01

    .... To assess the impact of polystyrene microspheres (micro-PS) on the physiology of the Pacific oyster, adult oysters were experimentally exposed to virgin micro-PS (2 and 6 µm in diameter; 0.023 mg·L(-1...

  13. Polyacrolein microspheres

    Science.gov (United States)

    Rembaum, Alan (Inventor)

    1987-01-01

    Microspheres of acrolein homopolymers and copolymer with hydrophillic comonomers such as methacrylic acid and/or hydroxyethylmethacrylate are prepared by cobalt gamma irradiation of dilute aqueous solutions of the monomers in presence of suspending agents, especially alkyl sulfates such as sodium dodecyl sulfate. Amine or hydroxyl modification is achieved by forming adducts with diamines or alkanol amines. Carboxyl modification is effected by oxidation with peroxides. Pharmaceuticals or other aldehyde reactive materials can be coupled to the microspheres. The microspheres directly form antibody adducts without agglomeration.

  14. Preparation and characterization of PS/pAPBA core-shell microspheres

    Institute of Scientific and Technical Information of China (English)

    Changling YAN; Yan LU; Shuyan GAO

    2009-01-01

    Polystyrene microspheres with an average diameter of 55 μm were prepared by suspension polymerization via oxidation of the monomer by ammonium persulfate. Poly-3-aminophenylboronic acid was grafted onto the surfaces of the polystyrene microspheres to form polystyrene/poly-3-aminophenylboronic acid core- shell micospheres. The samples were characterized by scanning electron microscopy, Raman spectroscopy, X-ray photo-electron spectroscopy and nitrogen adsorption/desorption method. The results show that poly-3-aminophenylboronic acid was successfully grafted to the surfaces of the polystyrene microspheres by aromatic ring electron-pairing interaction. The surfaces of the core-shell micro-spheres possessed a porous structure, with the average pore diameter of 30.2 nm and the BET surface area of 193.26 m2/g.

  15. Preparation method of polystyrene core-poly (acrylamide-acrylic acid )shell fluorescent microspheres%聚苯乙烯核-聚(丙烯酰胺-丙烯酸)壳荧光素微球制备方法的研究

    Institute of Scientific and Technical Information of China (English)

    姚晚侠; 杨彪; 李群; 孙耀杰

    2011-01-01

    目的:为制备性能良好的核壳结构荧光微球,探讨了加料方式、引发剂选择、交联剂使用、pH调节、浓度配比和溶胀处理等反应条件对形成壳结构的效果以及形态学上的影响.方法:通过以乳液聚合得到的荧光素微球为核,以丙烯酰胺、丙烯酸为壳结构的聚合单体,制得了聚苯乙烯核-聚(丙烯酰胺-丙烯酸)壳荧光素微球.结果:荧光显微镜显示:粒径均一,分布范围7~8 μm.红外吸收光谱证实了聚(丙烯酰胺-丙烯酸)壳结构以及表面酰胺基的存在.该种子聚合反应的最佳条件为:在不使用交联剂的前提下以偶氮二异丁腈为引发剂,经过40 h的乙醇溶胀处理,70℃反应3 h,反应过程pH值在6~7之间.该荧光微球的平均载药量和包封率分别为25.14%和90.21%,其荧光释放率40 h后稳定在30%左右.结论:用此法制备的微球具有良好的荧光性能和明显的核壳结构,分散性和稳定性良好,其载药量和包封率也相对稳定,并具有良好的缓释性能.%Objective: To investigate the preparation method of polystyrene core-poly (acrylamideacrylic acid) shell fluorescent microspheres. Methods: The polystyrene core-poly (acrylamide-acrylic acid) shell (P-(St-co-AAM) ) fluorescent microspheres were prepared using fluorescent microspheres as the core and acrylamide/acrylic as polymerization monomer. Reaction conditions affecting the morphology of core-shell structure including feeding mode, initiator, cross linker, pH, concentration and swelling were studied. Results: Fluorescent microscopy showed that the relatively uniform particle sizes were distributed in a range of 7 -8 μm. Fourier transform infra-red spectroscopy(FT-IR) proved the existence of poly (acrylamide-acrylic acid ) shell and amide group on the surface. The optimal conditions for seeding polymerization: azobisisobutyronitrile was used as the initiator in the absence of cross linker, after a 40 h swelling treatment by using

  16. A facile method to produce highly monodispersed nanospheres of cystine aggregates

    Science.gov (United States)

    Han, Hongliang; Wang, Chungang; Ma, Zhanfang; Su, Zhongmin

    2006-10-01

    Multiple shapes of nano- and micro-structured cystine aggregates, including spheres, rods, spindles, dendrites, and multipods, were easily synthesized just by adjusting the concentrations and pH values of L-Cysteine solutions under ultrasonic irritation. Importantly, highly monodispersed nanospheres of cystine aggregates 225 nm in diameter without any other shapes were easily obtained for the system of 0.1 M L-Cysteine with pH 8. This will provide a very simple and effective approach to produce monodispersed cystine microspheres, which could promote new possibilities for future applications in biosensor, drug delivery, medicine, and the production of nanomaterials.

  17. A facile method to produce highly monodispersed nanospheres of cystine aggregates

    Energy Technology Data Exchange (ETDEWEB)

    Han Hongliang; Wang Chungang; Ma Zhanfang; Su Zhongmin [Chemistry Department, Northeast Normal University, Changchun 130024 (China)

    2006-10-28

    Multiple shapes of nano- and micro-structured cystine aggregates, including spheres, rods, spindles, dendrites, and multipods, were easily synthesized just by adjusting the concentrations and pH values of L-Cysteine solutions under ultrasonic irritation. Importantly, highly monodispersed nanospheres of cystine aggregates 225 nm in diameter without any other shapes were easily obtained for the system of 0.1 M L-Cysteine with pH 8. This will provide a very simple and effective approach to produce monodispersed cystine microspheres, which could promote new possibilities for future applications in biosensor, drug delivery, medicine, and the production of nanomaterials.

  18. Synthesis of 3D ordered porous polystyrene using silica template

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A rigid colloidal silica template was formed by self-assembly ofthe monodispersed silica spheres prepared according to St-ber method. The silica template is highly ordered, which was verified by bright color effect due to Bragg diffraction and the results of SEM. The free radical polymerization of styrene was allowed within the interstices of the rigid template to result in the formation of the three- dimensional periodic silica/polystyrene nano-composites. The titled porous polystyrene was prepared by chemical decom- position of the template with concentrated aqueous hydro- fluoric acid. Scanning electron microscopy characterization showed that the macroporous polystyrene has ordered arrays of the uniform pores replicated from the template. Moreover, it was found that the morphology of the as-synthesized macroporous polystyrene was greatly affected by the connectivity of the silica spheres treated under different conditions.

  19. Multiplexed magnetic microsphere immunoassays for detection of pathogens in foods

    OpenAIRE

    Kim, Jason S.; Chris R Taitt; Ligler, Frances S.; Anderson, George P.

    2010-01-01

    Foodstuffs have traditionally been challenging matrices for conducting immunoassays. Proteins, carbohydrates, and other macromolecules present in food matrices may interfere with both immunoassays and PCR-based tests, and removal of particulate matter may also prove challenging prior to analyses. This has been found true when testing for bacterial contamination of foods using the standard polystyrene microspheres utilized with Luminex flow cytometers. Luminex MagPlex microspheres are encoded ...

  20. In Vitro Cytotoxicity and Protein Drug Release Properties of Chitosan/Heparin Microspheres

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Chitosan/heparin microspheres were prepared using the water-in-oil emulsification solvent evaporation technique. The microsphere diameters were controlled by selecting the fabrication process parameters. Scanning electron micrographs showed that the chitosan/heparin microspheres were regular and the surface morphology was smooth. Fourier transform infrared showed that the chitosan amino groups reacted with heparin carboxylic groups to form acylamides in the microspheres. Analysis of the microsphere cytotoxicity showed that they had no cytotoxic effect and behaved very similar to the negative control (polystyrene).To analyze the protein drug release profiles of the microspheres, bovine serum albumin was loaded as a model drug into the microspheres and released in vitro. Marked retardation was observed in the BSA release profiles. The results show that chitosan/heparin microspheres may provide a useful controlled release protein drug system for used in pharmaceutics.

  1. Spatial refractive index sensor using whispering gallery modes in an optically trapped microsphere

    NARCIS (Netherlands)

    Zijlstra, P.; Zijlstra, Peter; van der Molen, K.L.; Mosk, Allard

    2007-01-01

    The authors propose the use of an optically trapped, dye doped polystyrene microsphere for spatial probing of the refractive index at any position in a fluid. Using the dye embedded in the microsphere as an internal broadband excitation source the authors eliminated the need for a tunable excitation

  2. Spatial refractive index sensor using whispering gallery modes in an optically trapped microsphere

    NARCIS (Netherlands)

    Zijlstra, Peter; Molen, van der Karen L.; Mosk, Allard P.

    2007-01-01

    The authors propose the use of an optically trapped, dye doped polystyrene microsphere for spatial probing of the refractive index at any position in a fluid. Using the dye embedded in the microsphere as an internal broadband excitation source the authors eliminated the need for a tunable excitation

  3. Preparation of large monodisperse vesicles.

    Directory of Open Access Journals (Sweden)

    Ting F Zhu

    Full Text Available Preparation of monodisperse vesicles is important both for research purposes and for practical applications. While the extrusion of vesicles through small pores (approximately 100 nm in diameter results in relatively uniform populations of vesicles, extrusion to larger sizes results in very heterogeneous populations of vesicles. Here we report a simple method for preparing large monodisperse multilamellar vesicles through a combination of extrusion and large-pore dialysis. For example, extrusion of polydisperse vesicles through 5-microm-diameter pores eliminates vesicles larger than 5 microm in diameter. Dialysis of extruded vesicles against 3-microm-pore-size polycarbonate membranes eliminates vesicles smaller than 3 microm in diameter, leaving behind a population of monodisperse vesicles with a mean diameter of approximately 4 microm. The simplicity of this method makes it an effective tool for laboratory vesicle preparation with potential applications in preparing large monodisperse liposomes for drug delivery.

  4. Raspberry-like PS/CdTe/Silica Microspheres for Fluorescent Superhydrophobic Materials

    OpenAIRE

    Chang, Jinghui; Zang, Linlin; Wang, Cheng; Sun, Liguo; Chang, Qing

    2016-01-01

    Superhydrophobic particulate films were fabricated via deposition of raspberry-like fluorescent PS/CdTe/silica microspheres on clean glass substrates and surface modification. Particularly, the fluorescent microspheres were prepared by a kind of modified strategy, namely introducing poly (acrylic acid)-functionalized polystyrene microspheres and thiol-stabilized CdTe quantum dots into a hydrolysis reaction of tetraethoxysilane simultaneously. And through adjusting the reaction parameters, the...

  5. 界面溶蚀法制备多孔磺化聚苯乙烯/壳聚糖微球及其Cr3+吸附研究%Preparation of porous sulphonated polystyrene/chitosan microspheres via solvent/nonsolvent induced phase separation and its application on adsorption Cr3+

    Institute of Scientific and Technical Information of China (English)

    李鑫; 宋林勇; 周艺峰; 聂王焰; 陈鹏鹏

    2014-01-01

    Sulfonated Polystyrene( SPS)microsPheres were used as temPlates and core-shell SPS/CS mi-crosPheres were PrePared by adsorbing chitosan onto the SPS surface via electrostatic interaction between amino and sulfoacid grouPs. Porous structured SPS and SPS/CS microsPheres were PrePared by solvent/nonsolvent induced Phase seParation method. Transmission electron microscoPy( TEM)was used to ob-serve the microstructure and the Cr3+ adsorPtion behavior was characterized by UV-Vis at room temPera-ture. The results indicated that the uniform morPhology of the Porous Polymer microsPheres was PrePared by interface dissolution method. And the Porous SPS/CS showed an obviously enhanced maximum adsorP-tive caPacity to Cr3+.%采用固/液界面溶剂溶胀诱导相分离法,对磺化聚苯乙烯( SPS)和表面负载有生物相容性的壳聚糖( CS)的核壳型SPS/CS两种微球进行溶蚀,制备出具有多孔结构的SPS和SPS/CS微球。研究发现,溶剂类型和醇水比是影响多孔聚合物微球形态的主要因素。利用透射电镜( TEM)对多孔微球的结构进行表征,通过紫外可见分光光度计( UV-Vis)测定SPS/CS多孔微球在室温环境下对Cr3+的吸附行为。结果表明,界面溶蚀法可制备出形貌均一的多孔聚合物微球,其对Cr3+吸附量明显优于实心结构的微球。

  6. Preparation and surface modification of magnetic poly(methyl methacrylate) microspheres

    Institute of Scientific and Technical Information of China (English)

    YANG; Chengli; GUAN; Yueping; XING; Jianmin; LIU; Junguo

    2004-01-01

    [1]Kronick, P., Gilpin, R. W., Use of superparamagnetic particles for isolation of cells, J. Biochem. Biophy. Methods, 1986, 12: 73-80.[2]Li, X. H., Sun, Z. H., Synthesis of magnetic polymer microspheres and application for immobilization of proteinase of balillus sublitis, J. Appl. Polym. Sci., 1995, 58: 1991-1997.[3]Abudiab, T., Beitle, R. R., Preparation of magnetic immobilized metal affinity separation media and its use in the isolation of proteins, J. Chromatogr. A, 1998, 795:211-217.[4]Josephson, L., Magnetic particles for use in separations, US Patent, 4 672 040, 1987-06-09.[5]Cupta, P. K., Hung, C. T., Magnetically controlled targeted mi cro-carrier systems, Life Sci., 1989, 44: 175-186.[6]Kondo, A., Kamura, H., Higashitahi, K., Development and application of thermosenstive magnetic immunomicrospheres for antibody purification, Appl. Microbiol. Biotechnol., 1994, 41: 99-105.[7]Horák, D., Magnetic polyglycidylmethacrylate microspheres by dispersion polymerization, J. Polym. Sci., Part A: Polym. Chem.,2001, 39: 3707-3715.[8]Lee, J., Senna, M., Preparation of monodispersed polystyrene microspheres uniformly coated by magnetite via heterogeneous polymerization, Colloid Polym. Sci., 1995, 273: 76-82.[9]Liu, X. Q., Guan, Y. P., Xing, J. M. et al., Synthesis and properties of micron-size magnetic polymeric spheres with epoxy group,Chinese J. Chem. Eng., 2003, 11: 731-735.[10]Daniel, Magnetic polymer latex and preparation process, US Patent, 4 358 388, 1982-11-09.[11]Ugelstad, J., Ellingsen, T., Berge, A. et al., Magnetic Polymer Particles, PCT Int. Appl., WO Patent, 8 303 920, 1983-11-10.[12]Liu, X. Q., Liu, H. Z., Xing, J. M. et al., Preparation and characterization of superparamagnetic functional polymeric microspheres, China Particuology, 2003, 1: 76-79.[13]Wu, J. G., Modern Fourier Transform Infrared Spectroscopy Technology and Its Application (in Chinese), Beijing: Literature Press of Science and Technology

  7. 共轴微反应器制备单分散聚N-异丙基丙烯酰胺/蒙脱石纳米复合微凝胶%Preparation of monodisperse poly(N-isopropylacrylamide)/clay nanocomposite hydrogel microspheres using coaxial microfluidic device

    Institute of Scientific and Technical Information of China (English)

    纪磊鹏; 张青红; 李耀刚; 王宏志

    2011-01-01

    A monodisperse nanocomposite poly ( N-isopropylacrylamide)/clay ( PNIPAm/Clay) microspheres is synthesized with coaxial microfluidic device using clay as cross-linker. The disperse phase contains the monomer ( N-isopropylacrylamide) ( NIPAm) , the initiator ( potassium peroxydisulfate) ( KPS ) , the cross-linker ( clay) and deionized water. The immiscible continuous phase is composed of soya-bean oil and the catalyst ( tetramethyl ethylene diamine) ( TEMED) . The monomer, NIPAm , has three distinctive absorbance peaks at 917 ,965 , 992 cm -1 ,indicating the vibration of the monomer's C -C double bond. However, these characteristic peaks disappear in the FF-IR spectra of PNIPAm/Clay and the Si-O characteristic peaks of clay,l 000 cm -1 ,appears in the FT-IR spectra of PNIPAm/Clay.The effects of changing tips, the flow rate of continuous phase and the content of the surfactant on the size of the microgels are studied. The results show that the microgels from 300 μn to 450 μm can be synthesized by changing the Lips of the dispersed phase injection tube;The size of the microgels between 315 and 435 μm with dispersion coefflcient below 5% can be adjusted by changing the flow rate of continuous phase;The diameter of the microgels decreases when the content of the surfactant( polyglycerol polyricinoleate) ( PGPR) in the continuous phase increases.%以蒙脱石(Clay)为交联剂,采用含有N,N,N'N'-四甲基乙二胺(TEMED)的豆油溶液为连续相,含有单体N-异丙基丙烯酞胺(NIPAm)、引发剂过硫酸钾(KPS)和分散有蒙脱石的水溶液为分散相,在共轴毛细管微反应器中制备了单分散聚N-异丙基丙烯酞胺/蒙脱石(PNIPAm/Clay)复合微凝胶.红外光谱分析表明:单体的C=C双键的红外特征峰917、965cm-1和992 cm-1在聚合后的微凝胶红外谱图中消失,而Clay的Si-O键特征峰1000 cm-1则出现在微凝胶的红外谱图中.研究了不同内径的管头、分散相的流速和表面活性剂的浓度对微

  8. Fluorescent microspheres

    Science.gov (United States)

    Rembaum, A.

    1978-01-01

    Latex particles with attached antibodies have potential biochemical and environmental applications. Human red blood cells and lymphocytes have been labeled with fluorescent microspheres by either direct or indirect immunological technique. Immunolatex spheres can also be used for detecting and localizing specific cell surface receptors. Hormones and toxins may also be bondable.

  9. Fabrication of Macro-porous β-zeolite by Using Colloidal Polystyrene Spheres as a Template

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A β-zeolite/polystyrene composite material was synthesized by co-deposition of mono-disperse polystyrene spheres and nano β-zeolite particles in aqueous suspension on a vertical substrate. Macro-porous β-zeolite was obtained after the polystyrene template was removed by calcination. The micro/macro-pore structure of the prepared β-zeolite was highly ordered. In comparison with other assembly methods, the co-deposition method could obtain a highly ordered macro-porous material with relatively large zeolite filling particles, and therefore the co-deposition of particles with different size is a promising method for the fabrication of macro-porous materials.

  10. Mesoporous phenylalanine ammonia lyase microspheres with improved stability through calcium carbonate templating.

    Science.gov (United States)

    Cui, Jiandong; Zhao, Yamin; Tan, Zhilei; Zhong, Cheng; Han, Peipei; Jia, Shiru

    2017-05-01

    Cross-linked enzyme aggregates (CLEAs) have recently emerged as a promising method for enzyme immobilization due to its simplicity and low cost. However, a lack of good size and morphological control over the as-prepared CLEAs has limited their practical applications in some cases. Here, monodisperse spherical CLEAs of phenylalanine ammonia lyase (PAL microspheres) were prepared based on CaCO3 microtemplates. The preparation procedure involves filling porous CaCO3 microtemplates with the protein by salt precipitation, glutaraldehyde crosslinking, and dissolution of the microtemplates. The formulation of CaCO3 templates with controlled size was studied in detail. Characterization of the prepared PAL microspheres was investigated. The results showed that the PAL microspheres with high immobilization efficiency (79%) exhibited excellent stability, including increased tolerance to proteolysis, low pH, and denaturants, and excellent mechanical properties. For example, free PAL almost lost all activity after they were incubated in the presence of trypsin for 2min, whereas PAL microspheres still retained 95% of their initial activity. Moreover, scanning electron microscope, transmission electron microscope, and N2 adsorption-desorption isotherms revealed that the resultant PAL microspheres possessed good monodispersity and mesoporous structure instead of the amorphous clusters of conventional CLEAs with few pores. Compared with conventional CLEAs, the monodisperse PAL microspheres with mesoporous make them more potentially useful for biomedical and biotechnological applications.

  11. A Polystyrene Primer.

    Science.gov (United States)

    Daniel, Robert A.

    1985-01-01

    One of the most common disposable materials in our society is polystyrene, of which grocery store meat trays, egg cartons, and several kinds of protective packing materials are made. Describes the characteristics of five different polystyrenes and some suggested uses for art classes. (RM)

  12. Aerosol fabrication methods for monodisperse nanoparticles

    Science.gov (United States)

    Jiang, Xingmao; Brinker, C Jeffrey

    2014-10-21

    Exemplary embodiments provide materials and methods for forming monodisperse particles. In one embodiment, the monodisperse particles can be formed by first spraying a nanoparticle-containing dispersion into aerosol droplets and then heating the aerosol droplets in the presence of a shell precursor to form core-shell particles. By removing either the shell layer or the nanoparticle core of the core-shell particles, monodisperse nanoparticles can be formed.

  13. Dispersion Polymerization of Polystyrene Particles Using Alcohol as Reaction Medium

    Science.gov (United States)

    Cho, Young-Sang; Shin, Cheol Hwan; Han, Sujin

    2016-02-01

    In this study, monodisperse polystyrene nanospheres were prepared by dispersion polymerization using alcohol as reaction medium to prepare colloidal clusters of the latex beads. Polyvinylpyrrolidone (PVP) and 2-(methacryloyloxy)ethyltrimethylammonium chloride (MTC) were used as dispersion stabilizer and comonomer, respectively. The particle size could be controlled by adjusting the reactant compositions such as the amount of stabilizer, comonomer, and water in the reactant mixture. The size and monodispersity of the polymeric particles could be also controlled by changing the reaction medium with different alcohols other than ethanol or adjusting the polymerization temperature. The synthesized particles could be self-organized inside water-in-oil emulsion droplets by evaporation-driven self-assembly to produce colloidal clusters of the polymeric nanospheres.

  14. OBSERVATION OF ENERGY DISSIPATION PEAK IN POLYSTYRENE MELT ABOVE Tg

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper two different kinds of dynamic mechanical techniques (inversed torsion pendulum and energy dissipation apparatus) were used to study the dynamic behavior of atactic monodisperse polystyrene above glass transition.The plots of energy dissipation versus temperature were presented for two atactic polystyrene samples. An apparent energy dissipation peak occurred above Tg in each plot measured by the inversed torsion pendulum, and simultaneously the sample was found to flow assuredly at the moment. To exclude the influence of the flow and demonstrate there was a peak indeed above Tg, the energy dissipation apparatus was used, in which the samples were put into a cup. An obvious peak appeared,and it was in agreement with the peak observed by the inversed torsion pendulum. On basis of the results measured by the two kinds of apparatus, a conclusion is drawn that a peak occurrs above Tg, which gives a manifestation for the existence of the liquid-liquid transition.

  15. Fabrication and optical trapping of handling structures for reconfigurable microsphere magnifiers

    DEFF Research Database (Denmark)

    Bañas, Andrew Rafael; Vizsnyiczai, Gaszton; Búzás, András

    2013-01-01

    We demonstrate the use of microfabricated supporting structures for maneuvering and supporting polystyrene microspheres for use as magnifying lenses in imaging applications. The supporting structure isolates the trapping light from the magnifier, hence avoiding direct radiation to the sample being...... observed which could be damaging, especially for biological specimens. Using an optical trapping setup, we demonstrate the actuation of a microsphere not held by optical traps, and show the possibility of imaging through such microspheres. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation...

  16. Invertase immobilization by adsorption on polymer microspheres studied by radioiodination technique

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Alvaro A.A. de [Universidade Federal de Itajuba, MG (Brazil). Inst. de Ciencias Exatas. Dept. de Fisica e Quimica]. E-mail: alencar@unifei.edu.br; Pontin, Luiz F. [Universidade Federal de Itajuba, MG (Brazil). Inst. de Ciencias Exatas. Dept. de Matematica e Computacao]. E-mail: pontin@unifei.edu.br; Higa, Olga Z.; Ribela, Maria Tereza C.P. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Lab. de Biologia Molecular]. E-mail: ozahiga@ipen.br; Tomotani, Ester J.; Vitolo, Michele [Sao Paulo Univ., SP (Brazil). Faculdade de Ciencias Farmaceuticas. Dept. de Tecnologia Bioquimico-Farmaceutica]. E-mail: michenzi@usp.br

    2005-07-01

    In this paper, we report the study of the diffusion behavior of invertase onto polystyrene-divinylbenzene (PS-DVB) microspheres. To detect the surface concentration of protein adsorbed on the microspheres, the chloramine-T method was used to label invertase and has been applied to the study of protein sorption properties on the microspheres. The sorption isotherms and the diffusion coefficient (D{sub f}) were computed from experimental results and the concentration of bound invertase was determined in terms of the Fick's law. The Hill equation was applied to the data and the binding capacity of the microspheres were estimated. The results of adsorption show that the radiolabelling invertase method are efficacious at the protein surface concentration detection and can be used to investigate the enzyme immobilization by sorption properties of polymer microspheres. (author)

  17. Microsphere-Based Rapamycin Delivery, Systemic Versus Local Administration in a Rat Model of Renal Ischemia/Reperfusion Injury

    NARCIS (Netherlands)

    Zandstra, Jurjen; van Beuge, Marike M.; Zuidema, Johan; Petersen, Arjen H.; Staal, Mark; Duque, Luisa F.; Rodriguez, Sergio; Lathuile, Audrey A. R.; Veldhuis, Gert J.; Steendam, Rob; Bank, Ruud A.; Popa, Eliane R.

    2015-01-01

    The increasing prevalence and treatment costs of kidney diseases call for innovative therapeutic strategies that prevent disease progression at an early stage. We studied a novel method of subcapsular injection of monodisperse microspheres, to use as a local delivery system of drugs to the kidney. W

  18. Formation of Tough Films by Evaporation of Water from Dispersions of Elastomer Microspheres Crosslinked with Rotaxane Supramolecules.

    Science.gov (United States)

    Hiroshige, Seina; Kureha, Takuma; Aoki, Daichi; Sawada, Jun; Aoki, Daisuke; Takata, Toshikazu; Suzuki, Daisuke

    2017-06-22

    Compared to rigid microspheres that consist, for example, of polystyrene or silica, soft and deformable elastomer microspheres can be used to generate colorless transparent films upon evaporating the solvent from microsphere-containing dispersions. To obtain tough films, a post-polymerization reaction to crosslink the microspheres is usually necessary, which requires extra additives during the drying process. This restriction renders this film-formation technology complex and rather unsuitable for applications in which impurities are undesirable. In the present study, it is demonstrated that tough elastomer microspheres that are crosslinked with rotaxanes can form tough bulk films upon evaporation of water from microsphere dispersions, so that post-polymerization reactions are not required. The results of this study should thus lead to new applications including coatings for biomaterials that need complete removal of all impurities from the materials prior to use. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Supply Deficit of Polystyrene

    Institute of Scientific and Technical Information of China (English)

    Gao Chunyu

    2007-01-01

    @@ 1 Stable demand growth worldwide The operating rate of polystyrene units has stayed around 80% globally since 2000. Production capacity reached 19.36 million t/a, output was 15.7 million tons, consumption was 15.53 million tons and the operating rate was 81.1% in 2005.

  20. NARROW-DISPERSED CROSSLINKED CORE-SHELL POLYMER MICROSPHERES PREPARED BY SURFACE-INITIATED ATOM TRANSFER RADICAL POLYMERIZATION

    Institute of Scientific and Technical Information of China (English)

    Yu-zeng Zhao; Xin-lin Yang; Feng Bai; Wen-qiang Huang

    2005-01-01

    Grafting of polystyrene with narrowly dispersed polymer microspheres through surface-initiated atom transfer radical polymerization (ATRP) was investigated. Polydivinylbenzene (PDVB) microspheres were prepared by dispersion polymerization with poly(N-vinyl pyrrolidone) (PVP) as stabilizer. The surfaces of PDVB microspheres were chloromethylated by chloromethyl methyl ether in the presence of zinc chloride as catalyst to form chloromethylbenzene initiating core sites for subsequent ATRP grafting of styrene using CuC1/bpy as catalytic system. Polystyrene was found to be grafted not only from the particle surfaces but also from within a thin shell layer, resulting in the formation of particles size increased from 2.38-2.58 μm, which can further grow to 2.93 μm during secondary grafting polymerization of styrene. This demonstrates that grafting polymerization proceeds through a typical ATRP procedure with living nature. All of the prepared microspheres have narrow particle size distribution with coefficient of variation around 10%.

  1. Fabrication and optical properties of Alq 3 doped PMMA microsphere arrays templated by ZnO inverse opal structure

    Science.gov (United States)

    Fu, Ming; Deng, Lier; Zhao, Ailun; Wang, Yongsheng; He, Dawei

    2010-07-01

    PMMA microsphere arrays are fabricated by a double replicating method with common used polystyrene colloidal crystal template. High quality ZnO inverse opals formed by electrodeposition play the key role between the PMMA microsphere arrays and polystyrene colloidal crystals. The electrodeposition method has advantage on fabricating IO structures with high solid fraction. After the subsequently in-situ polymerization of MMA in the voids of ZnO inverse opals, the ZnO is removed by hydrochloric acid solution. Microsphere arrays fabricated by PMMA or PMMA doped with Alq 3 are prepared. Reflection stop bands are detected from the formed PMMA microsphere arrays. Solid fraction from 37% to 50% of the PMMA arrays can be formed by different in-situ polymerization modes of MMA. The photoluminescence of Alq 3 in the PMMA spheres is partly suppressed at the wavelength of the photonic stop band induced by PMMA arrays.

  2. Custom-Made Microspheres for Optical Tweezers.

    Science.gov (United States)

    Jannasch, Anita; Abdosamadi, Mohammad K; Ramaiya, Avin; De, Suman; Ferro, Valentina; Sonnberger, Aaron; Schäffer, Erik

    2017-01-01

    Due to their high position and force sensitivity and the ability to remotely apply forces and torques, optical tweezers are widely used in diverse fields, such as biology, material science, and physics. Often, small dielectric particles are trapped and used as probes, which for experimental convenience are mostly spherical and composed of silica or polystyrene. The optical properties of these materials together with the microsphere size determine the trapping efficiency, and the position and force resolution. However, using only a single, homogeneous, isotropic, and unstructured material limits the range of trapping properties and thereby the applications of optical tweezers. Here, we show how custom-made microspheres composed of coated high-refractive-index materials-titania and nanodiamonds-and birefringent, liquid crystals extend the range and combination of desired trapping properties. These custom-made microspheres either enable the generation of high forces, a high force or time resolution, or the applications of torques. Custom-made probes expand the range of possible experiments and approaches broadening the scope and applicability of optical tweezers.

  3. Amorphous Ni-P Hollow Spheres Prepared by Self-assembly of Ni-P Nanoparticles on Polystyrene Beads

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The first preparation of amorphous Ni-P/PS (polystyrene) core-shell and Ni-P hollow microspheres was per-formed using a surface seeding-electroless plating method. The preliminary magnetic properties of the amorphous Ni-P hollow sphere were investigated and compared with those of the Ni hollow sphere.

  4. 氘代聚苯乙烯胶体晶体的制备及光学性质研究%Fabrication and optical properties of deuterated polystyrene colloidal crystals

    Institute of Scientific and Technical Information of China (English)

    严鸿维; 张林; 吕海兵; 袁晓东; 任洪波

    2012-01-01

    以水作为介质合成了高度单分散的氘代聚苯乙烯微球,并利用垂直沉积法制备了高质量的氘代聚苯乙烯胶体晶体.傅立叶变换红外光谱清楚地表明氘代苯乙烯单体发生了聚合反应;扫描电镜表面分析展示出胶体微球的高度有序排列,断面分析表明氘代聚苯乙烯胶体晶体为面心立方结构;光学透射谱显示出氘代聚苯乙烯胶体晶体的高次布拉格衍射特征,通过和理论计算的能带结构对比,进一步证实了氘代聚苯乙烯胶体晶体为面心立方结构;变角度光学透射谱测量显示,随着入射角的增大,(111)面的衍射峰蓝移,而(200)和(220)面的衍射峰发生红移.%Highly monodisperse deuterated polystyrene colloidal spheres were synthesized in water medium. High-quality deuterated polystyrene colloidal crystals were fabricated by vertical deposition method. It was clearly shown that deuterated styrene monomers had generated a polymerization reaction through Fourier transform infrared spectroscopy. Highly ordered arrangement of colloidal microspheres was confirmed by scanning e-lectron microscopy, and it was considered to be face-centered cubic structure by cross-sectional image analysis. The transmission spectra of deuterated polystyrene colloidal crystals exhibited some characterization of high-order Bragg diffraction, which further confirmed the face-centered cubic close-packed structure of deuterated polystyrene colloidal crystals as compared to the calculated band structure. Angle resolved transmission spectra showed the diffraction peak of (111) plane was blueshifted, while the diffraction peaks of (200) and (220) planes were both redshifted as increasing the incident angles.

  5. Making Polymeric Microspheres

    Science.gov (United States)

    Rhim, Won-Kyu; Hyson, Michael T.; Chung, Sang-Kun; Colvin, Michael S.; Chang, Manchium

    1989-01-01

    Combination of advanced techniques yields uniform particles for biomedical applications. Process combines ink-jet and irradiation/freeze-polymerization techniques to make polymeric microspheres of uniform size in diameters from 100 to 400 micrometer. Microspheres used in chromatography, cell sorting, cell labeling, and manufacture of pharmaceutical materials.

  6. Flow cytometer system for single-shot biosensing based on whispering gallery modes of fluorescent microspheres

    Science.gov (United States)

    Lessard, Reno; Rousseau-Cyr, Olivier; Charlebois, Maxime; Riviere, Christophe; Mermut, Ozzy; Allen, Claudine Nı.

    2013-02-01

    We report an innovative label-free biosensor based on statistical analysis of several whispering gallery modes spectral shifts in polystyrene fluorescent microspheres using a custom microflow cytometer. Whispering gallery modes analysis enables detection of nanometer-sized analytes showing promising possibilities for virus, bacteria and molecular detection. To demonstrate this, fluorophore-doped microspheres of the appropriate size parameter are mixed in an aqueous solution. Then, a syringe pump pushes the solution through a fiber optic flow cell where a laser beam illuminates the analysis area to excite the microspheres and their fluorescence is collected. This device provides a low-cost and user friendly solution that could enhance spectrum acquisition rates up to 5 spectra per second thanks to the considerable amount of microspheres flowing through the excitation area per unit time. Finally, the fluorescence spectra are statistically investigated using an instantaneous measurement of apparent refractive index algorithm to determine a reliable value for the refractive index of the environment since the exact radius of the microsphere scanned is unknown. This refractive index becomes an effective value for the local perturbation caused by inhomogeneities on the microsphere surface and hence, determines whether or not inhomogeneities, such as bacteria, are adsorbed by comparing to a control sample. Combining a flow cell with our detection algorithm, we reduce the period of a 50 microspheres experiment from 161 minutes to 14 minutes when the flow rate is 2000 µl/h and the microsphere concentration is 5 µsphere/µl.

  7. Preparation of magnetic hierarchically porous microspheres with temperature-controlled wettability for removal of oils.

    Science.gov (United States)

    Tao, Shengyang; Ding, Yunzhe; Jiang, Lei; Li, Guangtao

    2017-04-15

    A series of monodispersed microspheres with hierarchically porous structures were prepared by microfluidic devices. Phase separation of the silica sol in microdroplets was adopted to construct these structures. The effects of velocity ratios (for both the continuous and the dispersed phases), collection solvents and calcination temperatures were investigated. The diameters of the microspheres were tuned from 148μm to 940μm by adjusting the velocity ratio. Tests revealed that the surface areas and pore volumes of the microspheres can reach 495m(2)g(-1) and 0.6068mlg(-1), respectively. The macroporous structure can be controlled by the collection solvents, and the wettability of the microspheres is determined by the calcination temperature. A calcination temperature of 450°C leads to a hydrophilic surface property. Fe3O4 nanoparticles were added to the silica sol to form magnetic microspheres, and the porous structure was not affected. This kind of hybrid microsphere adsorbs 3.29 times its own weight in toluene. These spheres can adsorb oil on water surfaces, and then be removed from the water with an external magnetic field. The microspheres can be recovered and reused more than 10 times. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Fabrication of Magnetic-Antimicrobial-Fluorescent Multifunctional Hybrid Microspheres and Their Properties

    Directory of Open Access Journals (Sweden)

    Ling-Han Xiao

    2013-04-01

    Full Text Available Novel magnetic-antimicrobial-fluorescent multifunctional hybrid microspheres with well-defined nanostructure were synthesized by the aid of a poly(glycidyl methacrylate (PGMA template. The hybrid microspheres were fully characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, Fourier transform infrared (FTIR, X-ray diffraction (XRD and digital fluorescence microscope. The as-synthesized microspheres PGMA, amino-modified PGMA (NH2-PGMA and magnetic PGMA (M-PGMA have a spherical shape with a smooth surface and fine monodispersity. M-PGMA microspheres are super-paramagnetic, and their saturated magnetic field is 4.608 emu·g−1, which made M-PGMA efficiently separable from aqueous solution by an external magnetic field. After poly(haxemethylene guanidine hydrochloride (PHGH functionalization, the resultant microspheres exhibit excellent antibacterial performance against both Gram-positive and Gram-negative bacteria. The fluorescence feature originating from the quantum dot CdTe endowed the hybrid microspheres with biological functions, such as targeted localization and biological monitoring functions. Combination of magnetism, antibiosis and fluorescence into one single hybrid microsphere opens up the possibility of the extensive study of multifunctional materials and widens the potential applications.

  9. Polymeric Microspheres for Medical Applications

    Directory of Open Access Journals (Sweden)

    Ketie Saralidze

    2010-06-01

    Full Text Available Synthetic polymeric microspheres find application in a wide range of medical applications. Among other applications, microspheres are being used as bulking agents, embolic- or drug-delivery particles. The exact composition of the spheres varies with the application and therefore a large array of materials has been used to produce microspheres. In this review, the relation between microsphere synthesis and application is discussed for a number of microspheres that are used for different treatment strategies.

  10. Mobilization of microspheres from a fractured soil during intermittent infiltration events

    Science.gov (United States)

    Mohanty, Sanjay; Bulicek, Mark; Metge, David W.; Harvey, Ronald W.; Ryan, Joseph N.; Boehm, Alexandria B.

    2015-01-01

    Pathogens or biocolloids mobilized in the vadose zone may consequently contaminate groundwater. We found that microspheres were mobilized from a fractured soil during intermittent rainfall and the mobilization was greater when the microsphere size was larger and when the soil had greater water permeability.The vadose zone filters pathogenic microbes from infiltrating water and consequently protects the groundwater from possible contamination. In some cases, however, the deposited microbes may be mobilized during rainfall and migrate into the groundwater. We examined the mobilization of microspheres, surrogates for microbes, in an intact core of a fractured soil by intermittent simulated rainfall. Fluorescent polystyrene microspheres of two sizes (0.5 and 1.8 mm) and Br− were first applied to the core to deposit the microspheres, and then the core was subjected to three intermittent infiltration events to mobilize the deposited microspheres. Collecting effluent samples through a 19-port sampler at the base of the core, we found that water flowed through only five ports, and the flow rates varied among the ports by a factor of 12. These results suggest that flow paths leading to the ports had different permeabilities, partly due to macropores. Although 40 to 69% of injected microspheres were retained in the core during their application, 12 to 30% of the retained microspheres were mobilized during three intermittent infiltration events. The extent of microsphere mobilization was greater in flow paths with greater permeability, which indicates that macropores could enhance colloid mobilization during intermittent infiltration events. In all ports, the 1.8-mm microspheres were mobilized to a greater extent than the 0.5-mm microspheres, suggesting that larger colloids are more likely to mobilize. These results are useful in assessing the potential of pathogen mobilization and colloid-facilitated transport of contaminants in the subsurface under natural infiltration

  11. Processing and Characterization of Sol-Gel Cerium Oxide Microspheres

    Energy Technology Data Exchange (ETDEWEB)

    McClure, Zachary D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Padilla Cintron, Cristina [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-09-27

    Of interest to space exploration and power generation, Radioisotope Thermoelectric Generators (RTGs) can provide long-term power to remote electronic systems without the need for refueling or replacement. Plutonium-238 (Pu-238) remains one of the more promising materials for thermoelectric power generation due to its high power density, long half-life, and low gamma emissions. Traditional methods for processing Pu-238 include ball milling irregular precipitated powders before pressing and sintering into a dense pellet. The resulting submicron particulates of Pu-238 quickly accumulate and contaminate glove boxes. An alternative and dust-free method for Pu-238 processing is internal gelation via sol-gel techniques. Sol-gel methodology creates monodisperse and uniform microspheres that can be packed and pressed into a pellet. For this study cerium oxide microspheres were produced as a surrogate to Pu-238. The similar electronic orbitals between cerium and plutonium make cerium an ideal choice for non-radioactive work. Before the microspheres can be sintered and pressed they must be washed to remove the processing oil and any unreacted substituents. An investigation was performed on the washing step to find an appropriate wash solution that reduced waste and flammable risk. Cerium oxide microspheres were processed, washed, and characterized to determine the effectiveness of the new wash solution.

  12. Fluorescent Polystyrene Sulfonate for Polyelectrolyte Studies

    Science.gov (United States)

    Huberty, Wayne; Tong, Xiaowei; Balamurugan, Sreelatha; Zhang, Donghui; Russo, Paul

    2012-02-01

    The slow-mode decay found by dynamic light scattering for polyelectrolytes in low-salt conditions has perplexed investigators since its first observation. Many characterization methods have suggested temporary or transient aggregation, although there is still no consensus on the cause. Many different polyelectrolytes demonstrate the slow-mode decay, but the sodium salt of polystyrene sulfonate (NaPSS) is the most popular choice for study. Commercially available NaPSS may have hydrophobic patches due to incomplete sulfonation leading to associations apart from any putative ionic mechanisms. Therefore, essentially full sulfonation, or ``patchless'', NaPSS should be synthesized. To facilitate fluorescence measurements, which can provide new insights to the slow-mode phenomenon, the material must be rendered fluorescent (F-NaPSS). Several approaches to F-NaPSS have appeared; some labeled a previously synthesized NaPSS without concern for its hydrophobic patches. Other strategies include a free radical copolymerization of styrene sulfonate and a vinyl amine to provide side chains viable for labeling. This method is successful, but yields only small amounts of nearly monodisperse polymer after fractionation. In this presentation, a high-yield synthesis of fully sulfonated, low-polydispersity, fluorescently tagged polymer will be discussed.

  13. Tuning the optical forces on- and off-resonance in microspherical photonics

    CERN Document Server

    Li, Yangcheng; Jofre, Ana; Astratov, Vasily N

    2015-01-01

    Light pressure effect has been discovered long ago and has been used as an optical method to manipulate microand nanoparticles. It is usually considered as a nonresonant effect determined by the transfer of the momentum of light. However, recently we have observed that large polystyrene microspheres of 15-20 {\\mu}m diameters supporting high quality whispering gallery resonances can be optically propelled in water at an extraordinary high velocity along tapered fibers under resonant conditions. In this work we compare on- and off-resonant optical forces in microspherical photonics by controlling the detuning between the laser emission line and whispering gallery resonances. Our approach involves manipulation with microspheres using conventional optical tweezers and their advanced spectroscopic characterization in fiber-integrated setups. We demonstrate dramatic difference in the optical forces exerted on microspheres in the on-resonant and off-resonant cases. This method can be used to study spectral propertie...

  14. Synthesis of Hollow CdS-TiO2 Microspheres with Enhanced Visible-Light Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Yuning Huo

    2012-01-01

    Full Text Available CdS-TiO2 composite photocatalyst in the shape of hollow microsphere was successfully synthesized via the hard-template preparation with polystyrene microspheres followed by ion-exchange approach. The hollow CdS-TiO2 microspheres significantly extended the light adsorption into visible light region, comparing to TiO2 microspheres. It led to much higher photocatalytic activities of hollow CdS-TiO2 microspheres than that of TiO2 during the photodegradation of rhodamine B under visible light irradiations. Furthermore, the well-remained hollow structure could achieve light multireflection within the interior cavities and the separation of photo-induced electrons and holes is efficient in CdS-TiO2, which were facilitated to improving the photoactivity.

  15. Microsphere Insulation Panels

    Science.gov (United States)

    Mohling, R.; Allen, M.; Baumgartner, R.

    2006-01-01

    Microsphere insulation panels (MIPs) have been developed as lightweight, longlasting replacements for the foam and vacuum-jacketed systems heretofore used for thermally insulating cryogenic vessels and transfer ducts. The microsphere core material of a typical MIP consists of hollow glass bubbles, which have a combination of advantageous mechanical, chemical, and thermal-insulation properties heretofore available only separately in different materials. In particular, a core filling of glass microspheres has high crush strength and low density, is noncombustible, and performs well in soft vacuum.

  16. Novel Au/La-SrTiO3 microspheres: superimposed effect of gold nanoparticles and lanthanum doping in photocatalysis.

    Science.gov (United States)

    Wang, Guannan; Wang, Pei; Luo, He-Kuan; Hor, T S Andy

    2014-07-01

    Novel multielement Au/La-SrTiO(3) microspheres were synthesized by a solvothermal method using monodisperse gold and La-SrTiO(3) nanocrystals as building blocks. The porous Au/La-SrTiO(3) microspheres had a large surface area of 94.6 m(2)  g(-1). The stable confined Au nanoparticles demonstrated strong surface plasmon resonance effect, leading to enhanced absorption in a broad UV/Vis/NIR range. Doping of rare-earth metal La also broadened the absorption band to the visible region. Both the conduction and valence bands of Au/La-SrTiO(3) microspheres thus show favorable potential for proton reduction under visible light. The superimposed effect of Au nanoparticles and La doping in Au/La-SrTiO(3) microspheres led to high photocurrent density in photoelectrochemical water splitting and good photocatalytic activity in photodegradation of rhodamine B. The photocatalytic activities are in the order of the following: Au/La-SrTiO(3) microspheres>Au/SrTiO(3) microspheres>La-SrTiO(3) microspheres>SrTiO(3) microspheres.

  17. Elongational dynamics of multiarm polystyrene

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.; Skov, Anne Ladegaard; Nielsen, Jens Kromann

    2009-01-01

    The startup of uni-axial elongational flow followed by stress relaxation and reversed bi-axial flow has been measured for a branched polystyrene melt with narrow molar mass distribution using the filament stretching rheometer. The branched polystyrene melt was a multiarm A(q)-C-C-A(q) pom-pom pol...

  18. Packing Products: Polystyrene vs. Cornstarch

    Science.gov (United States)

    Starr, Suzanne

    2009-01-01

    Packing materials such as polystyrene take thousands of years to decompose, whereas packing peanuts made from cornstarch, which some companies are now using, can serve the same purpose, but dissolve in water. The author illustrates this point to her class one rainy day using the sculptures students made from polystyrene and with the cornstarch…

  19. Organic aerogel microspheres

    Science.gov (United States)

    Mayer, Steven T.; Kong, Fung-Ming; Pekala, Richard W.; Kaschmitter, James L.

    1999-01-01

    Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  20. Organic aerogel microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, S.T.; Kong, F.M.; Pekala, R.W.; Kaschmitter, J.L.

    1999-06-01

    Organic aerogel microspheres are disclosed which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonstick gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  1. Spontaneous Breakup of Extended Monodisperse Polymer Melts

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.; Yu, Kaijia

    2011-01-01

    We apply continuum mechanical based, numerical modeling to study the dynamics of extended monodisperse polymer melts during the relaxation. The computations are within the ideas of the microstructural ‘‘interchain pressure’’ theory. The computations show a delayed necking resulting in a rupture...

  2. Nanomechanical properties of multi-block copolymer microspheres for drug delivery applications.

    Science.gov (United States)

    Moshtagh, P R; Rauker, J; Sandker, M J; Zuiddam, M R; Dirne, F W A; Klijnstra, E; Duque, L; Steendam, R; Weinans, H; Zadpoor, A A

    2014-06-01

    Biodegradable polymeric microspheres are interesting drug delivery vehicles for site-specific sustained release of drugs used in treatment of osteoarthritis. We study the nano-mechanical properties of microspheres composed of hydrophilic multi-block copolymers, because the release profile of the microspheres may be dependent on the mechanical interactions between the host tissues and the microspheres that aim to incorporate between the cartilage surfaces. Three different sizes of monodisperse microspheres, namely 5, 15, and 30μm, were tested in both dry and hydrated (swollen) states. Atomic force microscopy was used for measuring nanoindentation-based force-displacement curves that were later used for calculating the Young׳s moduli using the Hertz׳s contact theory. For every microsphere size and condition, the measurements were repeated 400-500 times at different surface locations and the histograms of the Young׳s modulus were plotted. The mean Young׳s modulus of 5, 15, and 30μm microspheres were respectively 56.1±71.1 (mean±SD), 94.6±103.4, and 57.6±58.6MPa under dry conditions and 226.4±54.2, 334.5±128.7, and 342.5±136.8kPa in the swollen state. The histograms were not represented well by the average Young׳s modulus and showed three distinct peaks in the dry state and one distinct peak in the swollen state. The peaks under dry conditions are associated with the different parts of the co-polymeric material at the nano-scale. The measured mechanical properties of swollen microspheres are within the range of the nano-scale properties of cartilage, which could favor integration of the microspheres with the host tissue.

  3. Fabrication of CeO2 by sol-gel process based on microfluidic technology as an analog preparation of ceramic nuclear fuel microspheres

    CERN Document Server

    Ye, Bin; Li, Jiaolong; Zhao, Zichen; Chang, Zhenqi; Serra, Christophe A

    2012-01-01

    Microfluidics integrated with sol-gel processes is introduced in preparing monodispersed MOX nuclear fuel microspheres using nonactive cerium as a surrogate for uranium or plutonium. The detailed information about microfluidic devices and sol-gel processes are provided. The effects of viscosity and flow rate of continuous and dispersed phase on size and size distribution of CeO2 microspheres have been investigated. A comprehensive characterization of the CeO2 microspheres has been conducted, including XRD pattern, SEM, density, size and size distribution. The size of prepared monodisperse particles can be controlled precisely in range of 10{\\mu}m to 1000{\\mu}m and the particle CV is below 3%.

  4. SYNTHESIS AND PROPERTIES OF POLYSTYRENE/LAPONITE NANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Wan-guo Hou; Wei-an Zhao; Dong-xiang Li

    2004-01-01

    Exfoliated polystyrene (PS)/laponite nanocomposites were prepared successfully. The characteristic d001diffraction peak of organo-laponite disappeared in the XRD patterns of nanocomposites, indicating that the laponite layers were exfoliated and the ordered crystal structure of laponite was destroyed because of the styrene polymerization. TEM observations showed that the exfoliated laponite primary particles were dispersed randomly in the PS matrix with lateral dimensions from 1 nm to 10 nm. SEM results showed that the PS/laponite nanocomposite particles were almost monodispersed spheres with the size of about 120 nm. Because of the interaction between PS and laponite nanolayers, the nanocomposites exhibited higher thermal stability and glass transition temperature when compared to pure PS.

  5. Dynamics and Morphology of Sulfonated Polystyrene Ionomers by Dielectric Spectroscopy

    Science.gov (United States)

    Castagna, Alicia; Wang, Wenqin; Winey, Karen I.; Runt, James

    2009-03-01

    The dynamics of sulfonated polystyrene (SPS) ionomers, in both the acid and neutralized forms, were investigated using broadband dielectric spectroscopy. The influences of acid content, counterion type (Zn, Na and Cs), degree of neutralization, and microphase separated morphology on segmental and local dynamics, as well as on Maxwell -- Wagner -- Sillars interfacial polarization, were examined. Ionomers prepared from SPS containing 1.9 mol% sulfonic acid species exhibit a broader segmental process indicative of a considerably broader distribution of local environments, as compared to those in unneutralized SPS. Moreover, multiple segmental relaxations were identified in the dielectric spectra of Zn and Na neutralized SPS (1.9 mol%) ionomers, likely indicating two distinct environments arising from ion clustering. A combination of STEM imaging and X-ray scattering confirmed the presence of monodisperse spherical ionic aggregates that were homogeneously distributed in the polymer matrix.

  6. Dynamics of Sulfonated Polystyrene Ionomers by Dielectric Relaxation Spectroscopy

    Science.gov (United States)

    Castagna, Alicia; Wang, Wenqin; Winey, Karen; Runt, James

    2010-03-01

    Broadband dielectric spectroscopy was used to investigate the dynamics of sulfonated polystyrene (SPS) ionomers, in both the acid and neutralized form. This study seeks to elucidate the role of counter ion type (Zn, Na, and Cs), degree of sulfonation (9 and 6%), and ion cluster morphology on the relaxation phenomena of SPS. Degree of neutralization and ion type have been found to significantly impact the breadth and time scale of the segmental relaxation process. High temperature relaxation processes, tentatively proposed to arise from Maxwell-Wagner-Sillars interfacial polarization and a hydrogen bonding relaxation, have also been identified. Bands in the sulfonate stretching region of FTIR spectra reveal information about ion coordination in the local aggregate environment. A combination of scanning transmission electron microscopy imaging and X-ray scattering confirmed the presence of homogeneously distributed, nearly monodisperse spherical ionic aggregates in the polymer matrix.

  7. A microfluidic approach to assembling ordered microsphere arrays

    Science.gov (United States)

    Xu, W.; Sur, K.; Zeng, H.; Feinerman, A.; Kelso, D.; Ketterson, J. B.

    2008-07-01

    Hydrodynamic flow through an array of channels has been utilized to assemble microspheres on a flat surface. The channels, about 6 µm in lateral size, were etched through a 60 µm thick silicon wafer using deep reactive ion etching (DRIE). Droplets containing 6-8 µm fluorescent polystyrene microspheres were placed on the top side of the horizontally-oriented silicon wafer, while the bottom side was connected to a syringe that draws the fluid through the channels. In this way the microspheres are guided and secured at the inlets of the channels, and remain in place when the suction ceases. This technique, which combines favorable features such as high throughput, high resolution rate and reusability, can be a powerful platform for a new generation of protein microarrays. Antigens can be bound to the microspheres as 'targets', which can then be exposed to different fluorescence-tagged antibodies so that their binding can be confirmed. This system can also be used to study the functional roles of gene fragments and their relations to human diseases. The high throughput feature will make it possible to screen a large number of DNA fragments and identify the genetic basis of various diseases effectively.

  8. Hollow mesoporous titania microspheres: New technology and enhanced photocatalytic activity

    Science.gov (United States)

    Feng, Zhenliang; Wei, Wenrui; Wang, Litong; Hong, Ruoyu

    2015-12-01

    Hollow titania microspheres (HTS) were fabricated via a sol-gel process by coating the hydrolysis product of titanium tetrabutoxide (TBOT) onto the amino (-NH2) modified porous polystyrene cross-linked divinyl benzene (PS-DVB) microspheres under changing atmospheric pressure, followed by calcination in nitrogen and air atmosphere. Particularly, the atmospheric pressure was continuously and regularly changed during the formation process of PS-DVB@TiO2 microspheres. Then the TiO2 particles were absorbed into the pores and onto the surface of PS-DVB as well. The resultant HTS (around 2 μm in diameter) featured a high specific surface area (84.37 m2/g), anatase crystal and stable hollow microsphere structure, which led to high photocatalysis activity. The photocatalytic degradation of malachite green (MG) organic dye solution was conducted under ultraviolet (UV) light irradiation, which showed a high photocatalytic ability (81% of MG was degraded after UV irradiation for 88 min). Therefore, it could be potentially applied for the treatment of wastewater contaminated by organic pollutants.

  9. Superhydrophobic bionic surfaces with hierarchical microsphere/SWCNT composite arrays.

    Science.gov (United States)

    Li, Yue; Huang, Xing Jiu; Heo, Sung Hwan; Li, Cun Cheng; Choi, Yang Kyu; Cai, Wei Ping; Cho, Sung Oh

    2007-02-13

    Superhydrophobic bionic surfaces with hierarchical micro/nano structures were synthesized by decorating single-walled or multiwalled carbon nanotubes (CNTs) on monolayer polystyrene colloidal crystals using a wet chemical self-assembly technique and subsequent surface treatment with a low surface-energy material of fluoroalkylsilane. The bionic surfaces are based on the regularly ordered colloidal crystals, and thus the surfaces have a uniform superhydrophobic property on the whole surface. Moreover, the wettability of the bionic surface can be well controlled by changing the distribution density of CNTs or the size of polystyrene microspheres. The morphologies of the synthesized bionic surfaces bear much resemblance to natural lotus leaves, and the wettability exhibited remarkable superhydrophobicity with a water contact angle of about 165 degrees and a sliding angle of 5 degrees.

  10. Microsphere-chain waveguides: Focusing and transport properties

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Kenneth W., E-mail: kallen62@uncc.edu; Astratov, Vasily N., E-mail: astratov@uncc.edu [Department of Physics and Optical Science, Center for Optoelectronics and Optical Communications, University of North Carolina at Charlotte, Charlotte, North Carolina 28223-0001 (United States); Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, Ohio 45433 (United States); Darafsheh, Arash; Abolmaali, Farzaneh [Department of Physics and Optical Science, Center for Optoelectronics and Optical Communications, University of North Carolina at Charlotte, Charlotte, North Carolina 28223-0001 (United States); Mojaverian, Neda; Limberopoulos, Nicholaos I. [Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, Ohio 45433 (United States); Lupu, Anatole [Institut d' Electronique Fondamentale, UMR 8622 CNRS, Universite Paris-Sud XI, 91405 Orsay (France)

    2014-07-14

    It is shown that the focusing properties of polystyrene microsphere-chain waveguides (MCWs) formed by sufficiently large spheres (D ≥ 20λ, where D is the sphere diameter and λ is the wavelength of light) scale with the sphere diameter as predicted by geometrical optics. However, this scaling behavior does not hold for mesoscale MCWs with D ≤ 10λ resulting in a periodical focusing with gradually reducing beam waists and in extremely small propagation losses. The observed effects are related to properties of nanojet-induced and periodically focused modes in such structures. The results can be used for developing focusing microprobes, laser scalpels, and polarization filters.

  11. Crystallization phenomena of isotactic polystyrene

    NARCIS (Netherlands)

    Lemstra, Peter Jan

    1975-01-01

    In this thesis the crystallization behavior of isotactic polystyrene has been described. The kinetics of the crystallization process and the crystalline structure were studied both for crystallization in the bulk and from dilute solutions. ... Zie Summary

  12. Casting Using A Polystyrene Pattern

    Science.gov (United States)

    Vasquez, Peter; Guenther, Bengamin; Vranas, Thomas; Veneris, Peter; Joyner, Michael

    1993-01-01

    New technique for making metal aircraft models saves significant amount of time and effort in comparison with conventional lost-wax method. Produces inexpensive, effective wind-tunnel models. Metal wind-tunnel model cast by use of polystyrene pattern.

  13. Template synthesis of monodisperse carbon nanodots

    Science.gov (United States)

    Kurdyukov, D. A.; Eurov, D. A.; Stovpiaga, E. Yu.; Kirilenko, D. A.; Konyakhin, S. V.; Shvidchenko, A. V.; Golubev, V. G.

    2016-12-01

    Monodisperse carbon nanodots in pores of mesoporous silica particles are obtained by template synthesis. This method is based on introducing a precursor (organosilane) into pores, its thermal decomposition with formation of carbon nanodots, and the template removal. Structural analysis of the nanomaterial has been performed, which showed that carbon nanodots have an approximately spherical form and a graphite-like structure. According to dynamic light scattering data, the size of carbon nanodots is 3.3 ± 0.9 nm.

  14. Ultrafast hydrothermal synthesis of high quality magnetic core phenol-formaldehyde shell composite microspheres using the microwave method.

    Science.gov (United States)

    You, Li-Jun; Xu, Shuai; Ma, Wan-Fu; Li, Dian; Zhang, Yu-Ting; Guo, Jia; Hu, Jack J; Wang, Chang-Chun

    2012-07-17

    An ultrafast, facile, and efficient microwave hydrothermal approach was designed to fabricate magnetic Fe(3)O(4)/phenol-formaldehyde (PF) core-shell microspheres for the first time. The structure of the Fe(3)O(4)/PF core-shell microspheres could be well controlled by the in situ polycondensation of phenol and formaldehyde with magnetic Fe(3)O(4) clusters as the seeds in an aqueous solution without any surfactants. The effect of synthetic parameters, such as the feeding amounts of phenol, the dosages of formaldehyde, the reaction temperatures, and the microwave heating time, on the morphologies and sizes of the Fe(3)O(4)/PF microspheres were investigated in details. The phenol-formaldehyde shell is found to be evenly coated on Fe(3)O(4) clusters within 10 min of the irradiation. The as-prepared microspheres were highly uniform in morphology, and the method was found to allow the shell thickness to be finely controlled in the range of 10-200 nm. The properties of the composite microspheres were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetic analysis (TGA), Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The as-prepared Fe(3)O(4)/PF microspheres were monodisperse and highly dispersible in water, ethanol, N,N-dimethyformamide, and acetone, a beneficial quality for the further functionalization and applications of the Fe(3)O(4)/PF microspheres.

  15. Newly designed silver coated-magnetic, monodisperse polymeric microbeads as SERS substrate for low-level detection of amoxicillin

    Science.gov (United States)

    Kibar, Güneş; Topal, Ahmet Emin; Dana, Aykutlu; Tuncel, Ali

    2016-09-01

    We report the preparation of silver-coated magnetic polymethacrylate core-shell nanoparticles for use in surface-enhanced Raman scattering based drug detection. Monodisperse porous poly (mono-2-(methacryloyloxy)ethyl succinate-co-glycerol dimethacrylate), poly (MMES-co-GDMA) microbeads of ca. 5 μm diameter were first synthesized through a multistage microsuspension polymerization technique to serve as a carboxyl-bearing core region. Microspheres were subsequently magnetized by the co-precipitation of ferric ions, aminated through the surface hydroxyl groups and decorated with Au nanoparticles via electrostatic attraction. An Ag shell was then formed on top of the Au layer through a seed-mediated growth process, resulting in micron-sized monodisperse microbeads that exhibit Raman enhancement effects due to the roughness of the Ag surface layer. The core-shell microspheres were used as a new substrate for the detection of amoxicillin at trace concentrations up to 10-8 M by SERS. The proposed SERS platform can be evaluated as a useful tool for the follow-up amoxicillin pollution and low-level detection of amoxicillin in aqueous media.

  16. Doppler cooling a microsphere

    CERN Document Server

    Barker, P F

    2010-01-01

    Doppler cooling the center-of-mass motion of an optically levitated microsphere via the velocity dependent scattering force from narrow whispering gallery mode (WGM) resonances is described. Light that is red detuned from the WGM resonance can be used to damp the center-of-mass motion in a process analogous to the Doppler cooling of atoms. Leakage of photons out of the microsphere when the incident field is near resonant with the narrow WGM resonance acts to damp the motion of the sphere. The scattering force is not limited by saturation, but can be controlled by the incident power. Cooling times on the order of seconds are calculated for a 20 micron diameter silica microsphere trapped within optical tweezers, with a Doppler temperature limit in the microKelvin regime.

  17. Morphology and photoluminescence of self-assembled CaWO4:Sm3+ microspheres: effect of pH and surfactant concentration

    Science.gov (United States)

    Ningombam, Goutam Singh; Nongmaithem, Rajmuhon Singh

    2017-03-01

    Self-assembled CaWO4:Sm3+ microspheres were prepared via surfactant (sodium dodecyl sulfate) mediated hydrothermal method. The effect of pH and the concentration of surfactant on the morphology and photoluminescence of the synthesized phosphors have been studied. Samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence spectroscopy. The microspheres were found to have an average size of 1-2 µm. They were mesoporous in nature and constituted of nanocrystals of about 10-30 nm dimension. The TEM images revealed the interlinking framework of the nano-sized constituents which consequently lead to the formation of mesoporous microspheres. The lowering of pH causes a slight reduction in the size of microspheres which could have been attributed to loss of OH from the nanoparticle surface and subsequent retardation in the adsorption of growing molecular CaWO4:Sm3+ units. Also, as pH increases, crystallinity decreases. The increase in amount of SDS reduced the crystallinity of the materials, destroyed the monodispersity of microspheres and lowered the luminescence output. It was found that lower pH and higher monodispersity of microspheres are quite favourable for high luminescence output.

  18. Tissue scattering parameter estimation through scattering phase function measurements by goniometer

    Institute of Scientific and Technical Information of China (English)

    Ying Zhu; Zhihua Ding; Martial Geiser

    2007-01-01

    @@ An automated optical system is built up to perform goniometric measurement of scattering phase function.Measurements of typical samples including monodisperse polystyrene micro-spheres solution, and mutlidisperse polystyrene micro-spheres solution are carried out in a dark room. The possibility of estimating the average particle size of phantom through analyzing its scattering phase function is demonstrated.

  19. Slip and flow dynamics of polydisperse thin polystyrene films.

    Science.gov (United States)

    Sabzevari, Seyed Mostafa; McGraw, Joshua D.; Jacobs, Karin; Wood-Adams, Paula M.

    2015-03-01

    We investigate the slip of binary and ternary mixtures of nearly monodisperse polystyrene samples on Teflon-coated (AF2400) silicon wafers using dewetting experiments. Binary mixtures of long and short chains along with ternary mixtures with a fixed weight-average molecular weight Mw but different number-average molecular weight Mn were prepared. Thin films of ca. 200 nm were spin coated on mica from polymer solutions and transferred to Teflon substrates. Above the glass transition temperature Tg the films break up via nucleation and growth of holes. The hole growth rate and rim morphology are monitored as a function of Mn and annealing protocol of the films before transfer to Teflon substrates. Slip properties, accessed using hydrodynamic models, and flow dynamics are then examined and compared. We found that the rim morphology and slip of polystyrene blends on Teflon depends on the molecular weight distribution. Similarly, flow dynamics is affected by the presence of short chains in mixture. Moreover, we can provoke differences in slip by choosing appropriate annealing and film transfer protocols for PS films that have first been spin cast on mica surfaces.

  20. Microfabrication of polystyrene microbead arrays by laser induced forward transfer

    Science.gov (United States)

    Palla-Papavlu, Alexandra; Dinca, Valentina; Paraico, Iurie; Moldovan, Antoniu; Shaw-Stewart, James; Schneider, Christof W.; Kovacs, Eugenia; Lippert, Thomas; Dinescu, Maria

    2010-08-01

    In this study we describe a simple method to fabricate microarrays of polystyrene microbeads (PS-μbeads) on Thermanox coverslip surfaces using laser induced forward transfer (LIFT). A triazene polymer layer which acts as a dynamic release layer and propels the closely packed microspheres on the receiving substrate was used for this approach. The deposited features were characterized by optical microscopy, scanning electron microscopy, atomic force microscopy, and Raman spectroscopy. Ultrasonication was used to test the adherence of the transferred beads. In addition, the laser ejection of the PS-μbead pixels was investigated by time resolved shadowgraphy. It was found that stable PS-μbeads micropatterns without any specific immobilization process could be realized by LIFT. These results highlight the increasing role of LIFT in the development of biomaterials, drug delivery, and tissue engineering.

  1. Preparation of polystyrene spheres in different particle sizes and assembly of the PS colloidal crystals

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Monodisperse polystyrene (PS) colloidal spheres were successfully prepared through emulsifier-free emulsion polymerization by controlling the polymerization reaction time, ionic strength of the system, concentration of the ionic copolymer (sodium p-styrenesulfonate) and other factors. The PS colloidal spheres were assembled into colloidal crystals whose structures were mainly face-centered cubic (fcc) close-packed. Then FDTD method was used to calculate the color-rendering characteristics of the colloidal crystals surface. The calculated results were consistent with the experimental results.

  2. Microspheres: Microfluidic Generation of Monodisperse and Photoreconfigurable Microspheres for Floral Iridescence-Inspired Structural Colorization (Adv. Mater. 26/2016).

    Science.gov (United States)

    Yeo, Seon Ju; Park, Kyung Jin; Guo, Kai; Yoo, Pil J; Lee, Seungwoo

    2016-07-01

    Flowering plants have advanced their colorization strategies to divide incoming white light into spatially sequenced vivid colors, especially by using 2D grating diffractive motifs. On page 5268, P. J. Yoo, S. Lee, and co-workers conceive a new idea for a microfluidic approach to mimic this wonderful biological strategy and its practical application to the color encoding of colloidal particles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Comparison of covalent and physical immobilization of lipase in gigaporous polymeric microspheres.

    Science.gov (United States)

    Wang, Weichen; Zhou, Weiqing; Li, Juan; Hao, Dongxia; Su, Zhiguo; Ma, Guanghui

    2015-11-01

    Lipase (EC 3.1.1.3) is a versatile enzyme which has been widely used in ester-reaction industries. We have previously discovered that gigaporous polystyrene (PST) microspheres can be used as a novel immobilization carrier for lipase. In this work, a series of gigaporous microspheres with different densities of epoxy group including poly(glycidyl methacrylate) (PGMA) and poly(styrene-co-glycidyl methacrylate) [P(ST-GMA)] were evaluated as lipase immobilization carriers, which were also compared with gigaporous PST microspheres and the commercial immobilized lipase Novozym 435. Lipase immobilized in gigaporous PGMA microspheres showed the highest activity yield, reusability, and stability as well as the best affinity for the substrate. The characterizations of adsorption curves, the change of epoxy group amounts, and hydrophobic-hydrophilic properties of the microspheres were carried out to investigate the interaction between lipase molecules and carriers. It was found that covalent binding played a key role in improving the properties of lipase immobilized in gigaporous PGMA microspheres.

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

    Science.gov (United States)

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

    2015-08-01

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

  5. Depletion induced encapsulation by dumbbell-shaped patchy colloids stabilize microspheres against aggregation.

    Science.gov (United States)

    Wolters, Joost Robert; Verweij, Joanne E; Avvisati, Guido; Dijkstra, Marjolein; Kegel, Willem K

    2017-03-08

    In this paper, we demonstrate the stabilization of polystyrene microspheres by encapsulating them with dumbbell-shaped colloids with a sticky and a non-sticky lobe. Upon adding a depletant, an effective short ranged attraction is induced between the microspheres and the smaller, smooth lobes of the dumbbells, making those specifically sticky, whereas the interaction with the larger lobes of the dumbbells is considerably less attractive due to their rough surface, which reduces the overlap volume and leaves them non-sticky. The encapsulation of the microspheres by these rough-smooth patchy dumbbells is investigated using a combination of experiments and computer simulations, both resulting in partial coverage of the template particles. For larger microspheres, the depletion attraction is stronger, resulting in a larger fraction of dumbbells that are attached with both lobes to the surface of microspheres. We thus find a template curvature dependent orientation of the dumbbells. In the Monte Carlo simulations, the introduction of such a small, curvature dependent attraction between the rough lobes of the dumbbells resulted in an increased coverage. However, kinetic constraints imposed by the dumbbell geometry seem to prevent optimal packing of the dumbbells on the template particles under all investigated conditions in experiments and simulations. Despite the incomplete coverage, the encapsulation by dumbbell particles does prevent aggregation of the microspheres, thus acting as a colloid-sized steric stabilizer.

  6. Thermal tuning the reversible optical band gap of self-assembled polystyrene photonic crystals

    Science.gov (United States)

    Vakili Tahami, S. H.; Pourmahdian, S.; Shirkavand Hadavand, B.; Azizi, Z. S.; Tehranchi, M. M.

    2016-11-01

    Nano-sized polymeric colloidal particles could undergo self-organization into three-dimensional structures to produce desired optical properties. In this research, a facile emulsifier-free emulsion polymerization method was employed to synthesize highly mono-disperse sub-micron polystyrene colloids. A high quality photonic crystal (PhC) structure was prepared by colloidal polystyrene. The reversible thermal tuning effect on photonic band gap position as well as the attenuation of the band gap was investigated in detail. The position of PBG can be tuned from 420 nm to 400 nm by varying the temperature of the PhC structure, reversibly. This reversible effect provides a reconfigurable PhC structure which could be used as thermo-responsive shape memory polymers.

  7. Doped zinc oxide microspheres

    Science.gov (United States)

    Arnold, Jr., Wesley D.; Bond, Walter D.; Lauf, Robert J.

    1993-01-01

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

  8. Polyvinyl pyridine microspheres

    Science.gov (United States)

    Rembaum, Alan (Inventor); Gupta, Amitava (Inventor); Volksen, Willi (Inventor)

    1980-01-01

    Microspheres are produced by cobalt gamma radiation initiated polymerization of a dilute aqueous vinyl pyridine solution. Addition of cross-linking agent provides higher surface area beads. Addition of monomers such as hydroxyethylmethacrylate acrylamide or methacrylamide increases hydrophilic properties and surface area of the beads. High surface area catalytic supports are formed in the presence of controlled pore glass substrate.

  9. A bioinspired color-changing polystyrene microarray as a rapid qualitative sensor for methanol and ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Wen-Kai, E-mail: wkkuo@nfu.edu.tw [Graduate Institute of Electro-Optical and Materials Science, National Formosa University, 64 Wenhua Road, Huwei, Yunlin 63208, Taiwan (China); Weng, Hsueh-Ping, E-mail: sherry.weng7949@gmail.com [Graduate Institute of Electro-Optical and Materials Science, National Formosa University, 64 Wenhua Road, Huwei, Yunlin 63208, Taiwan (China); Hsu, Jyun-Jheng, E-mail: k88520x@gmail.com [Graduate Institute of Electro-Optical and Materials Science, National Formosa University, 64 Wenhua Road, Huwei, Yunlin 63208, Taiwan (China); Yu, Hsin Her, E-mail: hhyu@nfu.edu.tw [Department of Biotechnology, National Formosa University, 64 Wenhua Road, Huwei, Yunlin 63208, Taiwan (China)

    2016-04-15

    Polystyrene (PS) microspheres were synthesized by emulsifier-free emulsion polymerization and arranged in an array of closely packed, opal-like photonic crystals by slow self-assembly through dip-coating. This periodic array of PS microspheres was then employed as a rapid qualitative sensor for methanol and ethanol. Both solvents could be detected rapidly based on the routes of their reflection coordinates in the chromaticity diagram or directly by the naked eye on the basis of the change in color within 1 min once a solvent sample had been placed on the PS photochromic sensor. This opal-like PS sensor can thus not only be employed as a rapid sensor for methanol and ethanol but can also be used as a powerful tool for the fast screening of illicit drugs and toxic chemicals during forensic investigations. - Highlights: • Opal-like array of polystyrene (PS) microspheres is synthesized by self-assembly. • This periodic PS array is used as a rapid sensor for methanol and ethanol. • Solvents are detected by routes of reflection coordinates in chromaticity diagram. • They are also detected directly by naked eye based on change in color of sensor. • The color change is irreversible for methanol but reversible for ethanol.

  10. Analysis of DNA-guided self-assembly of microspheres using imaging flow cytometry.

    Science.gov (United States)

    Tang, Hao; Deschner, Ryan; Allen, Peter; Cho, Younjin; Sermas, Patrick; Maurer, Alejandro; Ellington, Andrew D; Willson, C Grant

    2012-09-19

    Imaging flow cytometry was used to analyze the self-assembly of DNA-conjugated polystyrene microspheres. This technique enables quantitative analysis of the assembly process and thereby enables detailed analysis of the effect of structural and process variables on the assembly yield. In a demonstration of the potential of this technique, the influence of DNA strand base pair (bp) length was examined, and it was found that 50 bp was sufficient to drive the assembly of microspheres efficiently, forming not only dimers but also chainlike structures. The effect of stoichiometry on the yield was also examined. The analysis demonstrated that self-assembly of 50 bp microspheres can be driven nearly to completion by stoichiometric excess in a manner similar to Le Chatelier's principle in common chemical equilibrium.

  11. PLGA Microspheres Incorporated Gelatin Scaffold: Microspheres Modulate Scaffold Properties

    OpenAIRE

    Indranil Banerjee; Debasish Mishra; Maiti, Tapas K.

    2009-01-01

    Freeze drying is one of the popular methods of fabrication for poly(lactide-co-glycolide) (PLGA) microspheres incorporated polymer scaffolds. However, the consequence of microspheres incorporation on physical and biological properties of scaffold has not been studied yet. In this study, attempt has been made to characterize the effect of PLGA microsphere incorporation on the physical properties of freeze-dried gelatin scaffold and its influence on cytocompatibility. Scaffolds loaded with va...

  12. Steric stabilization of microspheres with grafted polyethylene oxide reduces phagocytosis by rat Kupffer cells in vitro.

    Science.gov (United States)

    Harper, G R; Davies, M C; Davis, S S; Tadros, T F; Taylor, D C; Irving, M P; Waters, J A

    1991-09-01

    Sterically stabilized polyethylene oxide-polystyrene copolymer microspheres, (PS-PEO) and charge stabilized polystyrene (PS) microspheres of similar size (1 micron) were prepared in order to compare their uptake by cultured rat Kupffer cells isolated by centrifugal elutriation. The uptake of the sterically stabilized particles was found to be much less than that for the charge stabilized control. The uptake of microspheres stabilized with covalently grafted PEO was lower or equivalent to that of control microspheres stabilized by the adsorption of the non-ionic PEO-polypropylene oxide (PPO-PEO) surfactant Poloxamer 238 or Methoxy-PEO. Phagocytic uptake by Kupffer cells at low and body temperature (8 degrees C and 37 degrees C) demonstrated that PS-PEO particles showed both low adherence and low metabolic uptake. The adsorption of PEO, as Poloxamer 238, to particles with covalently attached or grafted PEO resulted in a synergistic reduction in uptake that was greater than the individual effects of grafting and adsorption alone (P less than or equal to 0.001). It is suggested that this combination produces a more effective steric barrier on the particle surface with the Poloxamer adsorbing to the surface between the grafted PEO chains. The relevance to drug targeting/carrier systems is discussed.

  13. Preparation of Bauxite Ceramic Microsphere

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiaosu; LIU Pingan; LI Xiuyan; SHUI Anze; ZENG Lingke

    2007-01-01

    Ceramic microspheres were prepared by using Chinese bauxite as raw materials through the centrifugal spray drying method. The control technology of microsphere size, degree of sphericity was researched. The ceramic microspheres were sintered by a double sintering process. The microstructure and composition of ceramic microsphere were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray energy spectroscopy. The results show that the degree of sphericity of the ceramic microsphere was good and the particle size was 10-100 μm. The XRD analysis reveals that the main crystalline phase of the ceramic microsphere was α- Al2O3 and mullite (3Al2O3·2SiO2). The product can be used as reinforced material for composite material, especially for antiskid and hard wearing aluminum alloy coating.

  14. Preparation and application of solid phase extraction packing of zirconia microsphere coated with sulfonated crosslinked polystyrene%二氧化锆微球表面键合磺化交联聚苯乙烯固相萃取填料的制备及应用

    Institute of Scientific and Technical Information of China (English)

    申书昌; 柳玉辉; 肖晓杏

    2013-01-01

    以聚合诱导胶体凝聚法(PICA)制备二氧化锆微球,用钛酸酯偶联剂对其进行表面改性,使其接枝上碳碳双键基团.在溶液体系中,该双键与单体苯乙烯和二乙烯苯在自由基引发下交联聚合,形成的聚合物包覆在二氧化锆微球表面.再通过磺化方法将磺酸基离子连接到苯环上,得到阳离子交换固相萃取填料.通过红外光谱、扫描电镜/X射线能谱等手段对其进行了表征.将装填得到的固相萃取柱与高效液相色谱联用,测定了水中的甲基磺草酮、阿特拉津和乙草胺.3种化合物的色谱峰面积与质量浓度呈良好的线性关系,相关系数(r2)均大于0.99;甲基磺草酮、阿特拉津和乙草胺的检出限分别为5.41、6.72和13.4μg/L.结果表明,制得的聚合物包覆二氧化锆微球的粒径为6~8μm,用该填料制成的固相萃取小柱对3种目标物的吸附率高.%Zirconia microsphere was prepared by polymerization-induced colloid aggregation (PICA) method and carbon-carbon double bond was grafted onto its surface by titanic acid ester coupling reagent.Poly(styrene-divinylbenzene) was synthesized by free radical polymerization by using styrene,divinylbenzene and carbon-carbon double bond on the microsphere surface in solution system,so the polymer was coated on the microsphere surface.After the benzene ring of the polymer was sulfonated,the cation exchange packing for solid phase extraction (SPE) was obtained.The material was characterized by Fourier transform infrared spectroscopy,scanning electron microscope and X-ray energy dispersive spectroscopy.Three herbicides of mesotrione,atrazine and acetochlor in water were determined by the SPE cartridge coupled with high performance liquid chromatography (HPLC).In the range of 0.5-3.0 mg/L,the relationships between the peak areas and mass concentrations of mesotrione,atrazine and acetochlor were linear with the correlation coefficients of 0.993 6,0.992 5,0.991 9,respectively

  15. 21 CFR 177.1640 - Polystyrene and rubber-modified polystyrene.

    Science.gov (United States)

    2010-04-01

    ... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances... polystyrene and rubber-modified polystyrene used in food-packaging adhesives complying with § 175.105 of this... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polystyrene and rubber-modified polystyrene....

  16. Porogen effects in synthesis of uniform micrometer-sized poly(divinylbenzene) microspheres with high surface areas.

    Science.gov (United States)

    Hao, Dong-xia; Gong, Fang-ling; Wei, Wei; Hu, Guo-hua; Ma, Guang-hui; Su, Zhi-guo

    2008-07-01

    A new method of synthesizing uniform poly(divinylbenzene) (polyDVB) microspheres with high specific surface areas was designed by combining Shirasu porous glass (SPG) membrane emulsification, suspension polymerization, and post-crosslinking techniques. It was shown that the physicochemical properties of porogens have a great influence on the size distribution and porous features of microspheres. The low aqueous solubility of porogen facilitated preparation of uniform emulsions and microspheres, and high aqueous solubility led to polydispersed emulsions and poor microsphere yields. Such aqueous solubility effects can be tailored by adding a low molecular weight polystyrene (LPST) as costabilizer in porogen, thus improving the uniformity of microspheres. Moreover, different affinities of porogens for copolymers demonstrate various contributions to specific surface areas of microspheres in suspension polymerization especially post-crosslinking. Solvating porogen requires a much higher addition than nonsolvating porogen to obtain equal specific surface areas in polymerization, but has more potential to enhance the specific surface area in post-crosslinking. Two kinds of uniform microspheres were obtained with high specific surface areas, up to 706.6 m2/g by heptane and 937.5 m2/g by toluene.

  17. Biotin- and glycoprotein-coated microspheres: potential surrogates for studying filtration of cryptosporidium parvum in porous media.

    Science.gov (United States)

    Pang, Liping; Nowostawska, Urszula; Weaver, Louise; Hoffman, Gabrielle; Karmacharya, Anjuman; Skinner, Alexandra; Karki, Naveena

    2012-11-06

    Cryptosporidium parvum is a waterborne pathogen, yet no suitable surrogate has been established for quantifying its filtration removal in porous media. Carboxyl polystyrene microspheres with size, density, and shape similar to C. parvum were coated with biotin (free and containing amine, NH(2)) and glycoprotein. These biomolecules have isoelectric points similar to C. parvum (pH ≈ 2), and glycoprotein is a major type of surface protein that oocysts possess. Zeta potential (ζ) and filtration removal of particles in sand of two different grain sizes were examined. Compared to unmodified microspheres, modified microspheres achieved a superior match to the oocysts in ζ, concentration, mass recovery, and collision coefficient. They showed the same log reduction in concentration as oocysts, whereas results from unmodified microspheres deviated by 1 order of magnitude. Of the three types of modified microspheres, glycoprotein-coated microspheres best resembled oocyst concentration, despite having ζ similar to NH(2)-biotin-coated microspheres, suggesting that surface protein also played an important role in particle attachment on solid surfaces. With further validation in environmental conditions, the surrogates developed here could be a cost-effective new tool for assessing oocyst filtration in porous media, for example, to evaluate the performance of sand filters in water and wastewater treatment, water recycling through riverbank filtration, and aquifer recharge.

  18. Microfluidic Production of Monodisperse Perfluorocarbon Microdroplets

    Science.gov (United States)

    Li, David; Schalte, Kevin; Fowlkes, J. Brian; Bull, Joseph

    2010-11-01

    Acoustic droplet vaporization (ADV) is process in which liquid perfluorocarbon (PFC) microdroplets are vaporized using focused ultrasound to form gas bubbles that are approximately 125 times larger in volume. Gas embolotherapy is a novel cancer treatment that uses ADV in vivo to strategically form gas emoboli, which can lodge in the microcirculation and starve tumors. Current methods to produce PFC microdroplets, such has high speed shaking or sonication, result in polydisperse droplet distributions where a fraction of droplets fall within the 2-10 microns range. In the clinical application with such a droplet distribution, large droplets are filtered by the lungs and small droplets result in bubbles that are too small to lodge in the tumor vasculature. Consequently, there is a need for a monodisperse droplet distribution. A microfluidic based device has been developed in order to produce such monodisperse PFC microdroplets. The device used hydrodynamic flow focusing to create droplets with a mean diameter less than 10 microns in diameter. This work is supported by NIH grant R01EB006476.

  19. Preparation and Properties of Monodisperse SnO2 Hollow Micro/Nano Spheres%单分散SnO2中空微纳米球的制备和性质

    Institute of Scientific and Technical Information of China (English)

    蔡宏敏; 任素贞; 王萌; 贾翠英

    2013-01-01

      模板法是制备无机中空微纳米球的重要方法之一。本文以苯乙烯为单体,通过乳液聚合得到粒径约为620 nm的单分散聚苯乙烯(PS)微球。以磺化后的聚苯乙烯(PSS)微球为模板,利用阴阳离子静电吸附作用,将PSS与前驱体SnSO4中的Sn2+结合。通过Sn2+在乙醇-水介质中的水解作用得到核-壳复合结构,再经高温煅烧,得到SnO2中空微纳米球。实验对前驱体的浓度、表面活性剂的用量、反应时间及模板选择等方面做了研究,通过扫描电镜(SEM)、X射线衍射(XRD)、红外(IR)光谱、热重分析(TGA)、H2程序升温还原(H2-TPR)、Brunauer-Emmett-Tel er (BET)比表面积等技术深入探究SnO2中空微纳米球的结构,并对比中空SnO2与实心粒子的氧化还原特性。 BET和H2-TPR显示将SnO2制备成微纳米空心球后其比表面积增大,表面氧空位明显增多,氧化活性明显提高。从IR及XRD推断核-壳结构形成机理,进而优化出简单合理的实验方案,获得表面光滑、结构致密,包覆厚度可控的SnO2中空微纳米球。%Templating is one of the most important methods for preparation of inorganic hol ow micro/nano spheres. We prepared monodisperse polystyrene (PS) microspheres having a diameter of 620 nm by the emulsion polymerization of styrene. Sulfonated polystyrene (PSS) microspheres were used as a template, through electrostatic adsorption of anions and cations, for modification with Sn2 + from SnSO4 precursor. The core-shel composite structures thereby produced through Sn2+ hydrolysis in an ethanol-water medium were calcined at high temperature to remove PSS and to obtain SnO2 hol ow micro/nano spheres. We investigated the effects of precursor concentration, amount of surfactant, reaction time, and templates choice. Scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared (IR) spectroscopy, thermogravimetric analysis (TGA), H2 temperature programmed

  20. Application of monodispersive anion exchangers in sorption and separation of y3+ from Nd3+ and Sm3+ complexes with dcta

    Institute of Scientific and Technical Information of China (English)

    Halina Hubicka; Dorota Kolody(n)ska

    2008-01-01

    Rare earth complexes with trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (DCTA) of the Ln(dcta)- ype exhibited an unusual sequence of affinity on the polystyrene anion exchangers: pm3+>Nd3+>Sm3+>pr3+>Ce3+>Eu3+>Gd3+>La3+>Sc3+>Tb3+>Dy3+>Ho3+>y3+>Er3+>Tm3+>yb3+>Lu3+[1]. Taking into account the position of Y3+, Sm3+, and Nd3+ in this affinity series, for the monodispersive polystyrene anion exchangers, Lewafit MonoPlus M 500, Lewatit MonoPlus M 600, Lewatit MonoPlus MP 500, Lewatit MonoPlus MP 64,and for the heterodispersive anion exchanger, Lewatit MP 62, the weight (Dg,) and bed (Dv) distribution coefficients of these complexes and working ion exchange capacities (Cw) were determined. Based on these values, purifications of Y3+ from Nd3+ and y3+ from Sm3+ in the macro-micro component system on these anion exchangers were studied. The application potential of this method was highlighted for the separation of yz3+ in the presence of Nd3+ and Sm3+. With 1 L of monodispersive and strongly basic polystyrene gel anion exchanger Lewatit MonoPlus M 500 in the acetate form, it is possible to obtain approximately 79 g Y2O3 purified from Nd2O3 and 70 g Y2O3 purified from Sm2O3 in the same process condition.

  1. Hydrothermal synthesis of 3D hollow porous Fe3O4 microspheres towards catalytic removal of organic pollutants.

    Science.gov (United States)

    Wang, Xiansong; Huang, He; Li, Guoqing; Liu, Yi; Huang, Jiale; Yang, Da-Peng

    2014-01-01

    Three-dimensional hollow porous superparamagnetic Fe3O4 microspheres were synthesized via a facile hydrothermal process. A series of characterizations done with X-ray diffraction, Brunauer-Emmett-Teller method, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy indicated that the production of Fe3O4 microspheres possessed good monodispersity, uniform size distribution, hollow and porous structural characters, and strong superparamagnetic behavior. The obtained Fe3O4 microspheres have a diameter of ca. 300 nm, which is composed of many interconnected nanoparticles with a size of ca. 20 nm. The saturation magnetization is 80.6 emu·g(-1). The as-prepared products had promising applications as novel catalysts to remove organic pollutants (methylene blue) from wastewater in the presence of H2O2 and ultrasound irradiation.

  2. STUDIES ON POLYSILOXANE-POLYSTYRENE COMPOSITE LATEXES

    Institute of Scientific and Technical Information of China (English)

    HUANG Ying; LIU Xianglian; YU Yunzhao

    1994-01-01

    Polysiloxane-polystyrene composite latexes were prepared by two-stage emulsion polymerization. Polymerization of styrene in swollen polysiloxane latex particles were studied.Formation of simple polystyrene particle in the 2nd-stage polymerization depends on the particle size of the 1st-stage latex and the polymerization temperature. Polystyrene domains in the vulcanizates reinforce the silicone rubbers effectively.

  3. Functional magnetic microspheres

    Science.gov (United States)

    Yen, Shiao-Ping S. (Inventor); Rembaum, Alan (Inventor); Landel, Robert F. (Inventor)

    1981-01-01

    Functional magnetic particles are formed by dissolving a mucopolysaccharide such as chitosan in acidified aqueous solution containing a mixture of ferrous chloride and ferric chloride. As the pH of the solution is raised magnetite is formed in situ in the solution by raising the pH. The dissolved chitosan is a polyelectrolyte and forms micelles surrounding the granules at pH of 8-9. The chitosan precipitates on the granules to form microspheres containing the magnetic granules. On addition of the microspheres to waste aqueous streams containing dissolved ions, the hydroxyl and amine functionality of the chitosan forms chelates binding heavy metal cations such as lead, copper, and mercury and the chelates in turn bind anions such as nitrate, fluoride, phosphate and borate.

  4. Covalent immobilization of lipases on monodisperse magnetic microspheres modified with PAMAM-dendrimer

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Weiwei [Lanzhou University, State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology (China); Zhang, Yimei [Suzhou Research Academy of North China Electric Power University (China); Hou, Chen; Pan, Duo; He, Jianjun; Zhu, Hao, E-mail: zhuhao07@lzu.edu.cn [Lanzhou University, State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology (China)

    2016-02-15

    This paper reported an immobilization of Candida rugosa lipase (CRL) onto PAMAM-dendrimer-grafted magnetic nanoparticles synthesized by a modified solvothermal reduction method. The dendritic magnetic nanoparticles were amply characterized by several instrumental measurements, and the CRL was covalently anchored on the three generation supports with glutaraldehyde as coupling reagent. The amount of immobilized enzyme was up to 150 mg/g support and the factors related with the enzyme activity were investigated. The immobilization of lipase improved their performance in wider ranges of pH and temperature. The immobilized lipase exhibited excellent thermal stability and reusability in comparison with free enzyme and can be reused 10 cycles with the enzymatic activity remained above 90 %. The properties of lipase improved obviously after being immobilized on the dendritic supports. The inactive immobilized lipase could be regenerated with glutaraldehyde and Cu{sup 2+}, respectively. This synthetic strategy was facile and eco-friendly for applications in lipase immobilization.

  5. Cell wall protein and glycoprotein constituents of Aspergillus fumigatus that bind to polystyrene may be responsible for the cell surface hydrophobicity of the mycelium.

    Science.gov (United States)

    Peñalver, M C; Casanova, M; Martínez, J P; Gil, M L

    1996-07-01

    Cell surface hydrophobicity (CSH) of Aspergillus fumigatus grown both in complex medium (yeast extract/peptone/dextrose; YPD) and minimal (Vogel's N) medium was monitored by assessing attachment of polystyrene microspheres to the cell surface. It was found that mature mycelium was hydrophobic. Treatment of intact mycelium with beta-mercaptoethanol (beta ME) abolished binding of the microspheres to hyphal elements, and coating of the microspheres with beta ME extracts from mycelium inhibited their attachment to intact mycelial cells. A. fumigatus mycelium was tagged in vivo with biotin and treated with beta ME. The beta ME extracts were analysed by SDS-PAGE and Western blotting with both peroxidase-conjugated-ExtrAvidin and concanavalin A (ConA). This procedure allowed identification of cell wall surface proteins and glycoproteins. Rabbit polyclonal antisera were raised against beta ME extracts obtained from cells grown in YPD and Vogel's N media. These antisera defined some major cell-wall-bound antigens. SDS-PAGE and Western blotting analysis of the cell wall material released by beta ME and adsorbed on polystyrene microspheres revealed about 19 protein species with apparent molecular masses ranging from 20 to 70 kDa, and two high-molecular-mass glycoproteins of 115 and 210 kDa. Treatment of cells grown in YPD, but not those grown in Vogel's N medium, with beta ME released a 55 kDa polypeptide able to adsorb to polystyrene microspheres that was detectable with the antisera. The ability to bind to polystyrene particles exhibited by several protein and glycoprotein species released by beta ME treatment suggested that these cell wall moieties possess exposed hydrophobic domains that could be responsible for the CSH of mycelium.

  6. Low molecular weight block copolymers as plasticizers for polystyrene

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Karsten; Nielsen, Charlotte Juel; Hvilsted, Søren

    2005-01-01

    Polystyrene-b-alkyl, polystyrene-b-polybutadiene-b-polystyrene, and polystyrene-b-poly(propylene glycol)monotridecyl ether were synthesized using macro initiators and atom transfer radical polymerization or by esterifications of homopolymers. The aim was a maximum molecular weight of 4 kg...... for polystyrene-b-polyisoprene-b-polystyrene (SIS) block copolymers. The end use properties of SIS plasticized with polystyrene-b-alkyl, measured as tensile strength, is higher than for SIS plasticized with dioctyl adipate. The polystyrene-b-polybutadiene-b-polystyrene and polystyrene-bpoly(propylene glycol...

  7. Monodisperse microdroplet generation and stopping without coalescence

    Energy Technology Data Exchange (ETDEWEB)

    Beer, Neil Reginald

    2016-02-23

    A system for monodispersed microdroplet generation and trapping including providing a flow channel in a microchip; producing microdroplets in the flow channel, the microdroplets movable in the flow channel; providing carrier fluid in the flow channel using a pump or pressure source; controlling movement of the microdroplets in the flow channel and trapping the microdroplets in a desired location in the flow channel. The system includes a microchip; a flow channel in the microchip; a droplet maker that generates microdroplets, the droplet maker connected to the flow channel; a carrier fluid in the flow channel, the carrier fluid introduced to the flow channel by a source of carrier fluid, the source of carrier fluid including a pump or pressure source; a valve connected to the carrier fluid that controls flow of the carrier fluid and enables trapping of the microdroplets.

  8. Ringing phenomenon in silica microspheres

    Institute of Scientific and Technical Information of China (English)

    Chunhua Dong; Changling Zou; Jinming Cui; Yong Yang; Zhengfu Han; Guangcan Guo

    2009-01-01

    Whispering gallery modes in silica microspheres are excited by a tunable continuous-wave laser through the fiber taper. Ringing phenomenon can be observed with high frequency sweeping speed. The thermal nonlinearity in the microsphere can enhance this phenomenon. Our measurement results agree very well with the theoretical predictions by the dynamic equation.

  9. Tracer Diffusion of Polystyrene in Lightly Sulfonated Polystyrene

    Science.gov (United States)

    Xu, Chen; Zhou, Nancy; Burghardt, Wesley; Winey, Karen; Composto, Russell

    2005-03-01

    The tracer diffusion coefficient D^* of deuterated polystyrene (d-PS) (Mw = 65,900 g/mol) in lightly sulfonated polystyrene (P(S-SSx)) (Mw = 65,000 g/mol) as a function of sulfonation mole fraction (x) was measured by forward recoil spectrometry (FRES). For x sulfonation, according to D^* = Do exp(-0.14 Ns), where Ns is the number of sulfuric acid groups per chain. This slowing-down is attributed to an increase in the monomeric friction coefficient which increases with sulfonation. The diffusion mechanism includes both reptation and constraint release. The monomeric friction coefficient for d-PS in P(S-SSx) is compared with the coefficient for P(S-SSx) measured by rheology.

  10. Lanthanide-containing polymer microspheres by multiple-stage dispersion polymerization for highly multiplexed bioassays.

    Science.gov (United States)

    Abdelrahman, Ahmed I; Dai, Sheng; Thickett, Stuart C; Ornatsky, Olga; Bandura, Dmitry; Baranov, Vladimir; Winnik, Mitchell A

    2009-10-28

    We describe the synthesis and characterization of metal-encoded polystyrene microspheres by multiple-stage dispersion polymerization with diameters on the order of 2 mum and a very narrow size distribution. Different lanthanides were loaded into these microspheres through the addition of a mixture of lanthanide salts (LnCl(3)) and excess acrylic acid (AA) or acetoacetylethyl methacrylate (AAEM) dissolved in ethanol to the reaction after about 10% conversion of styrene, that is, well after the particle nucleation stage was complete. Individual microspheres contain ca. 10(6)-10(8) chelated lanthanide ions, of either a single element or a mixture of elements. These microspheres were characterized one-by-one utilizing a novel mass cytometer with an inductively coupled plasma (ICP) ionization source and time-of-flight (TOF) mass spectrometry detection. Microspheres containing a range of different metals at different levels of concentration were synthesized to meet the requirements of binary encoding and enumeration encoding protocols. With four different metals at five levels of concentration, we could achieve a variability of 624, and the strategy we report should allow one to obtain much larger variability. To demonstrate the usefulness of element-encoded beads for highly multiplexed immunoassays, we carried out a proof-of-principle model bioassay involving conjugation of mouse IgG to the surface of La and Tm containing particles and its detection by an antimouse IgG bearing a metal-chelating polymer with Pr.

  11. Functional hydrophilic polystyrene beads with uniformly size and high cross-linking degree facilitated rapid separation of exenatide.

    Science.gov (United States)

    Li, Qiang; Zhao, Lan; Zhang, Rongyue; Huang, Yongdong; Zhang, Yan; Zhang, Kun; Wu, Xuexing; Zhang, Zhigang; Gong, Fangling; Su, Zhiguo; Ma, Guanghui

    2016-04-01

    A high cross-linking polystyrene(PSt)-based anion-exchange material with uniformly size, high ion exchange capacity, and high hydrophilicity was synthesized by a novel surface functionalization approach in this study. Uniformly sized PSt microspheres were prepared by the membrane emulsion polymerization strategy, and then modified by (1) conversing resid ual surface vinyl groups to epoxy groups followed by quaternization, and (2) decorating aromatic ring matrix including nitration, reduction and attachment of glycidyltrimethylammonium chloride. The 3-D morphology and porous features of microspheres were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The surface of the modified PSt became roughness but the particle size remained same. Meanwhile, FT-IR spectra and laser scanning confocal microscope (LCSM) indicated that the modification groups had been successfully covalently coated onto the PSt microspheres. Modified PSt microspheres showed greatly improved hydrophilicity and biocompatibility with 0.387mmol/mL ion exchange capacity (IEC). In the application evaluation procedure, exenatide can be purified from 42.9% (peptide crudes) to 88.6% by modified PSt column with 97.1% recovery yield. This modified PSt microspheres had a large potential in application for efficient separation of peptides.

  12. Study on Synthesis of Polyacrylamide Microspheres and its Sealing Characteristics of Drilling Fluid

    Directory of Open Access Journals (Sweden)

    Mingming Cheng

    2014-02-01

    Full Text Available For the purpose of reducing the invasion depth of solid phase and liquid phase of drilling fluid and improving the quality of drilling mud cake, polyacrylamide microspheres were successfully composed via reversed phrase emulsion method. The physical and chemical structures of the samples as well as the grain-size variation were investigated by Transmission Electron Microscopy (TEM and Laser Particle Size Analysis method (LPSA.The plugging performance of the samples were investigated by core plugging experiment and sand bed filtration experiment. TEM images show that acrylamide has been polymerized, the products consist of a lot of monodisperse microspheres with a size of about 1-6 μm. LPSA images indicate that the particle size of polyacrylamide microspheres vary with time and temperature regularly. The experiment that simulates rock strata with different permeability shows those polyacrylamide microspheres can produce effectively blocked to the core and sand bed and then it establishes the foundation for the next field test.

  13. Multimodal Imaging of Nanocomposite Microspheres for Transcatheter Intra-Arterial Drug Delivery to Liver Tumors

    Science.gov (United States)

    Kim, Dong-Hyun; Li, Weiguo; Chen, Jeane; Zhang, Zhuoli; Green, Richard M.; Huang, Sui; Larson, Andrew C.

    2016-01-01

    A modern multi-functional drug carrier is critically needed to improve the efficacy of image-guided catheter-directed approaches for the treatment of hepatic malignancies. For this purpose, a nanocomposite microsphere platform was developed for selective intra-arterial transcatheter drug delivery to liver tumors. In our study, continuous microfluidic methods were used to fabricate drug-loaded multimodal MRI/CT visible microspheres that included both gold nanorods and magnetic clusters. The resulting hydrophilic, deformable, and non-aggregated microspheres were mono-disperse and roughly 25 um in size. Sustained drug release and strong MRI T2 and CT contrast effects were achieved with the embedded magnetic nano-clusters and radiopaque gold nanorods. The microspheres were successfully infused through catheters selectively placed within the hepatic artery in rodent models and subsequent distribution in the targeted liver tissues and hepatic tumors confirmed with MRI and CT imaging. These multimodal nanocomposite drug carriers should be ideal for selective intra-arterial catheter-directed administration to liver tumors while permitting MRI/CT visualization for patient-specific confirmation of tumor-targeted delivery. PMID:27405824

  14. Preparation of Functional Polymeric Microspheres

    Institute of Scientific and Technical Information of China (English)

    Changchun Wang; Yonghui Deng; Wuli Yang; Shoukuang Fu

    2005-01-01

    @@ 1Introduction Because of the wide applications in the area of biomedical and biotechnological fields, a great efforts have been done to fabricate different kinds of microspheres with tailored structural and surface properties over the last decade[1]. Among them, stimuli responsive microspheres are microspheres that show ability to change their physical-chemical properties and colloidal properties in response to environmental stimuli such as changes of temperature, pH, chemicals, light, electrical field, magnetic field or mechanic stress, etc. These microspheres have been under intensive study for their high potential applications in biomedical and biotechnological fields such as controlled drug delivery[2], biosensor[3], chemical isolation[4], cell culture substrates[5], enzyme immobilization[6], bioelectrocatalysis[7], and magnetically controlled electrochemical reaction[8]. However,most of the reported stimuli responsive microspheres only show response to one specific stimulus. Up to now,to the best of our knowledge, only a few works have been directed to the fabrication of microspheres which show response to more than one stimulus[9]. In this paper, a system synthesis method for stimuli responsive microspheres with more useful properties was reported, and the simple application in biomedical area have been mentioned.

  15. Toward Automatic Label-Free Whispering Gallery Modes Biodetection with a Quantum Dot-Coated Microsphere Population

    Science.gov (United States)

    Charlebois, M.; Paquet, A.; Verret, L. S.; Boissinot, K.; Boissinot, M.; Bergeron, M. G.; Allen, C. Nì.

    2010-03-01

    We explore a new calibration-free approach to biodetection based on whispering gallery modes (WGMs) without a reference measure and relative shifts. Thus, the requirement to keep track of the sensor position is removed, and a freely moving population of fluorophore-doped polystyrene microspheres can now fulfill this role of sensing resonator. Breaking free from fixed surface-based biosensing promotes adhesion between the microsphere sensors and the analytes since both can now be thoroughly mixed. The 70-nm-wide spectrum of green fluorescent microbeads allows us to monitor over 20 WGMs simultaneously without needing evanescent light coupling into the microspheres, hence enabling remote sensing. Since the exact radius of each microsphere is unknown a priori, it requires algorithmic analyses to obtain a reliable result for the refractive index of a solution. We first test our approach with different solutions of alcohol in water obtaining 3 × 10-4 precision on the refractive index at lower concentrations. Then, the solutions of bacterial spores in water yield clear evidence of biodetection in the statistical analysis of WGMs from 50 microspheres. To extend the fluorescence spectral range of our WGM sensors, we present preliminary results on coating microspheres with CdSe/ZnS quantum dots.

  16. Synthesis of the Supported Au Polystyrene/poly(acrylic acid) Composite Microspheres and Their pH Regulated Performance†%负载金纳米粒子的聚苯乙烯/聚丙烯酸微球的合成及pH响应性能

    Institute of Scientific and Technical Information of China (English)

    滕小波; 张春霞; 张颖

    2016-01-01

    The core-shell polystyrene( PS)/poly( acrylic acid) ( PAA) composite microgels with pH sensitivity were synthesized via two-step polymerization method. Au nanoparticles were supported onto pH sensitivity composite microgels via in situ reduction of chloroauric acid ( HAuCl4 ) using NaBH4 as reduction agent and sodium citrate as stabilizer. The results demonstrated that the plasmonic coupling of gold nanoparticles could be regulated, and the diffusion of reactive substrates availably controlled, due to the shrinkage and swelling performance of the shell chains under the different acid and alkali conditions. The optical property and catalytic activity of Au NPs could be regulated by changing the micro-environment of composite microgels. Therefore, the performance of composite materials could be realized the pH-controllable.%以两步聚合法合成的聚苯乙烯( PS)/聚丙烯酸( PAA)核-壳结构复合微凝胶为载体,硼氢化钠为还原剂,柠檬酸钠为稳定剂,通过原位控制性还原获得pH敏感性微凝胶负载纳米金粒子的PS/PAA-Au复合材料。研究发现,不同酸碱条件时,复合微凝胶壳层高分子链的溶胀/收缩变化,不仅可以调节纳米金粒子的表面等离子吸收,还可以调节反应底物的扩散传质,即借助载体微环境的变化来调控纳米金光学性能和催化性能,从而实现复合纳米金材料的pH调控性。

  17. Preparation of highly monodisperse fluorescent polymer particles by miniemulsion polymerization of styrene with a polymerizable surfactant.

    Science.gov (United States)

    Taniguchi, Tatsuo; Takeuchi, Naoki; Kobaru, Shotaro; Nakahira, Takayuki

    2008-11-01

    Miniemulsion polymerization of styrene (St) in the presence of a hydrophobe (hexadecane:HD) using a cationic polymerizable surfactant (N,N-dimethyl-N-n-dodecyl-N-2-methacryloyloxyethylammonium bromide:C(12)Br) and a cationic initiator (2,2'-azobis(2-amidinopropane) dihydrochloride:V50), called St/C(12)Br/V50 hereafter, proceeded efficiently compared with that using sodium dodecyl sulfate (SDS) and potassium persulfate (KPS), i.e., St/SDS/KPS, providing monodisperse polystyrene latex particles with a narrower particle size distribution. In St/C(12)Br/AIBN, where an oil-soluble initiator, i.e., 2,2'-azobisisobutyronitrile (AIBN), was used in place of V50, little changes in polymerization kinetics or in particle size distribution were observed, while a significant drop in polymerization rate and a broad particle size distribution were observed with St/SDS/AIBN. A polymerizable pyrene derivative (1-pyrenylmethyl methacrylate: PyMMA) was quantitatively incorporated into monodisperse latex particles in St/PyMMA/C(12)Br/V50 compared to pyrene (Py) in St/Py/C(12)Br/V50. Contrary to our expectation, however, increased excimer emission was observed with St/PyMMA/C(12)Br/V50 particles, indicating less evenly distributed pyrene chromophores in the particles. The fluorescence lifetime of pyrene chromophores in St/Py/C(12)Br/V50 particles was determined to be 286 ns, which was 17 times longer than that of pyrene in THF solution.

  18. Mucoadhesive Microsphere - Review

    Directory of Open Access Journals (Sweden)

    Ratnaparkhi M P

    2014-06-01

    Full Text Available Several approaches have been immerged to prolong the residence time of the dosage forms at the absorption site and one of them is the development of oral controlled release mucoadhesive system. Mucoadhesive drug delivery systems are used to enhance drug absorption in a site-specific manner. Bioadhesion has been defined as the attachment of synthetic or biological macromolecules to a biological tissue. The biological surface can be epithelial tissue or the mucous coat on the surface of a tissue. If adhesive attachment is to a mucous coat, the phenomenon is referred to as mucoadhesion. Mucus is a thin blanket covering all epithelia that are in contact with the external environment in the gastrointestinal, respiratory, and urogenital tracts. This approach involves the use of mucoadhesive polymers, which can adhere to the epithelial surface in the stomach. Carrier technology offers an intelligent approach for drug delivery by coupling the drug to a carrier particle such as microspheres, nanospheres, liposomes, nanoparticles, etc., which modulates the release and absorption of the drug. Microspheres constitute an important part of these particulate drug delivery systems by virtue of their small size and efficient carrier capacity.

  19. Refractometry of organosilica microspheres

    CERN Document Server

    Seet, K Y T; Nieminen, T A; Knoener, G; Rubinsztein-Dunlop, H; Trau, M; Zvyagin, A V; Seet, Katrina Y. T.; Vogel, Robert; Nieminen, Timo A.; Knoener, Gregor; Rubinsztein-Dunlop, Halina; Trau, Matt; Zvyagin, Andrei V.

    2007-01-01

    The refractive index of novel organosilica (nano/micro)material is determined using two methods. The first method is based on analysis of optical extinction efficiency of organosilica beads versus wavelength, which is obtained by a standard laboratory spectrometer. The second method relies on the measurable trapping potential of these beads in the focused light beam (laser tweezers). Polystyrene beads were used to test these methods, and the determined dispersion curves of refractive index values have been found accurate. The refractive index of organosilica beads has been determined to range from 1.60-1.51 over the wavelength range of 300-1100 nm.

  20. Copolymers of fluorinated polydienes and sulfonated polystyrene

    Science.gov (United States)

    Mays, Jimmy W.; Gido, Samuel P.; Huang, Tianzi; Hong, Kunlun

    2009-11-17

    Copolymers of fluorinated polydienes and sulfonated polystyrene and their use in fuel cell membranes, batteries, breathable chemical-biological protective materials, and templates for sol-gel polymerization.

  1. Increasing sensitivity and angle-of-view of mid-wave infrared detectors by integration with dielectric microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Kenneth W., E-mail: kenneth.allen@gtri.gatech.edu; Astratov, Vasily N., E-mail: astratov@uncc.edu [Department of Physics and Optical Science, Center for Optoelectronics and Optical Communications, University of North Carolina at Charlotte, Charlotte, North Carolina 28223-0001 (United States); Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, Ohio 45433 (United States); UES, Dayton, Ohio 45433 (United States); Abolmaali, Farzaneh [Department of Physics and Optical Science, Center for Optoelectronics and Optical Communications, University of North Carolina at Charlotte, Charlotte, North Carolina 28223-0001 (United States); Duran, Joshua M.; Ariyawansa, Gamini; Limberopoulos, Nicholaos I. [Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, Ohio 45433 (United States); Urbas, Augustine M. [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson AFB, Ohio 45433 (United States)

    2016-06-13

    We observed up to 100 times enhancement of sensitivity of mid-wave infrared photodetectors in the 2–5 μm range by using photonic jets produced by sapphire, polystyrene, and soda-lime glass microspheres with diameters in the 90–300 μm range. By finite-difference time-domain (FDTD) method for modeling, we gain insight into the role of the microspheres refractive index, size, and alignment with respect to the detector mesa. A combination of enhanced sensitivity with angle-of-view (AOV) up to 20° is demonstrated for individual photodetectors. It is proposed that integration with microspheres can be scaled up for large focal plane arrays, which should provide maximal light collection efficiencies with wide AOVs, a combination of properties highly attractive for imaging applications.

  2. PREPARATION OF POLY(ETHYLENEGLYCOL-co-ACRYLIC ACID) MICROSPHERES WITH DIVINYLBENZNE AS CROSSLINKER BY DISTILLATION-PRECIPITATION POLYMERIZATION

    Institute of Scientific and Technical Information of China (English)

    Zhao Dai; Xin-lin Yang; Wen-qiang Huang

    2007-01-01

    Monodisperse poly(poly(ethyleneglycol) methyl ether acrylate-co-acrylic acid) (poly(PEGMA-co-AA))microspheres were prepared by distillation-precipitation polymerization with divinylbenzene (DVB) as crosslinker with 2,2'-azobisisobutyronitrile (AIBN) as initiator in neat acetonitrile without stirring. Under various reaction conditions, four distinct morphologies including the sol, microemulsion, microgels and microspheres were formed during the distillation of the solvent from the reaction system. A 2D morphological map was established as a function of crosslinker concentration and the polar monomer AA concentration, in comonomer feed in the transition between the morphology domains. The effect of the covalent crosslinker DVB on the morphology of the polymer network was investigated in detail at AA fraction of 40 vol%.The ratios of acid to ethylene oxide units presenting in the comonomers dramatically affected the polymer-polymer interaction and hence the morphology of the resultant polymer network. The covalent crosslinking by DVB and the hydrogen bonding crosslinking between two acid units as well as between the acid and ethylene oxide unit played key roles in the formation of monodisperse polymer microspheres.

  3. Miscibility of Polystyrene and Lighted Sulfonated Polystyrene Blends

    Science.gov (United States)

    Zhou, N. C.; Burghardt, W. R.; Composto, R. J.

    2005-03-01

    The blend miscibility of deuterated polystyrene (dPS) and lighted sulfonated poly(styrene-ran-sulfonated polystyrene) (P (S-SS)) has been examined by forward recoil spectrometry (FRES). Equilibrium coexistence compositions were determined for dPS:P(S-SSx) blends where x is the mole percent of sulfonation.At x = 0.2%, the blends are fully miscible at 150°C to 190°C, while at x = 2.6% the system fully immiscible at the same temperatures. Intermediate levels of sulfonation (0.7, 1.0 and 1.2%) are partially miscible and exhibit an upper critical solution temperature (UCST). This behavior is attributed to the dilution of repulsive intra-molecular interaction between the ionic and non-ionic groups in the copolymer due to favorable interactions with the non-ionic group of the homopolymer PS. Estimates using the Flory-Huggins and the copolymer effect theories found a large ( 20) positive monomer-monomer interaction parameter between styrene and styrene sulfonate. This large interaction parameter might drive phase separation within a compositionally disperse random copolymers sample.

  4. Glass microsphere lubrication

    Science.gov (United States)

    Geiger, Michelle; Goode, Henry; Ohanlon, Sean; Pieloch, Stuart; Sorrells, Cindy; Willette, Chris

    1991-01-01

    The harsh lunar environment eliminated the consideration of most lubricants used on earth. Considering that the majority of the surface of the moon consists of sand, the elements that make up this mixture were analyzed. According to previous space missions, a large portion of the moon's surface is made up of fine grained crystalline rock, about 0.02 to 0.05 mm in size. These fine grained particles can be divided into four groups: lunar rock fragments, glasses, agglutinates (rock particles, crystals, or glasses), and fragments of meteorite material (rare). Analysis of the soil obtained from the missions has given chemical compositions of its materials. It is about 53 to 63 percent oxygen, 16 to 22 percent silicon, 10 to 16 percent sulfur, 5 to 9 percent aluminum, and has lesser amounts of magnesium, carbon, and sodium. To be self-supporting, the lubricant must utilize one or more of the above elements. Considering that the element must be easy to extract and readily manipulated, silicon or glass was the most logical choice. Being a ceramic, glass has a high strength and excellent resistance to temperature. The glass would also not contaminate the environment as it comes directly from it. If sand entered a bearing lubricated with grease, the lubricant would eventually fail and the shaft would bind, causing damage to the system. In a bearing lubricated with a solid glass lubricant, sand would be ground up and have little effect on the system. The next issue was what shape to form the glass in. Solid glass spheres was the only logical choice. The strength of the glass and its endurance would be optimal in this form. To behave as an effective lubricant, the diameter of the spheres would have to be very small, on the order of hundreds of microns or less. This would allow smaller clearances between the bearing and the shaft, and less material would be needed. The production of glass microspheres was divided into two parts, production and sorting. Production includes the

  5. PHOTOPHYSICAL STUDY OF SULFONATED POLYSTYRENE

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jixiang; LI Hexian; WANG Guochang; WANG Yuexi; HE Binglin

    2004-01-01

    The photophysical properties of a series of sulfonated micromolecule (paratoluenesulfonic acid, HPTS) and macromolecules (linear and crosslinked polystyrene) have been studied by steady-state fluorescence spectra. The results indicate that the ground sulfonated ring associations can form in both the micromolecules and the macromolecules. The fluorescence spectra of the sulfonated crosslinked copolymers appear a red-shift when the copolymers change from hydrogen-type to sodium-type, and some new emission bands appear in the long-wavelength region. These results are explained in terms of synergetic effect of hydrogen bond, π-π interaction and crosslinking effect.

  6. Effect of colloidal particle size on adsorbed monodisperse and bidisperse monolayers.

    Science.gov (United States)

    Rosenberg, Rachel T; Dan, Nily

    2011-07-19

    Coating hydrogel films or microspheres by an adsorbed colloidal shell is one synthesis method for forming colloidosomes. The colloidal shell allows control of the release rate of encapsulated materials, as well as selective transport. Previous studies found that the packing density of self-assembled, adsorbed colloidal monolayers is independent of the colloidal particle size. In this paper we develop an equilibrium model that correlates the packing density of charged colloidal particles in an adsorbed shell to the particle dimensions in monodisperse and bidisperse systems. In systems where the molar concentration in solution is fixed, the increase in adsorption energy with increasing particle size leads to a monotonic increase in the monolayer packing density with particle radius. However, in systems where the mass fraction of the particles in the adsorbing solutions is fixed, increasing particle size also reduces the molar concentration of particles in solution, thereby reducing the probability of adsorption. The result is a nonmonotonic dependence of the packing density in the adsorbed layer on the particle radius. In bidisperse monolayers composed of two particle sizes, the packing density in the layer increases significantly with size asymmetry. These results may be utilized to design the properties of colloidal shells and coatings to achieve specific properties such as transport rate and selectivity.

  7. Rapid enumeration of phage in monodisperse emulsions.

    Science.gov (United States)

    Tjhung, Katrina F; Burnham, Sean; Anany, Hany; Griffiths, Mansel W; Derda, Ratmir

    2014-06-17

    Phage-based detection assays have been developed for the detection of viable bacteria for applications in clinical diagnosis, monitoring of water quality, and food safety. The majority of these assays deliver a positive readout in the form of newly generated progeny phages by the bacterial host of interest. Progeny phages are often visualized as plaques, or holes, in a lawn of bacteria on an agar-filled Petri dish; however, this rate-limiting step requires up to 12 h of incubation time. We have previously described an amplification of bacteriophages M13 inside droplets of media suspended in perfluorinated oil; a single phage M13 in a droplet yields 10(7) copies in 3-4 h. Here, we describe that encapsulation of reporter phages, both lytic T4-LacZ and nonlytic M13, in monodisperse droplets can also be used for rapid enumeration of phage. Compartmentalization in droplets accelerated the development of the signal from the reporter enzyme; counting of "positive" droplets yields accurate enumeration of phage particles ranging from 10(2) to 10(6) pfu/mL. For enumeration of T4-LacZ phage, the fluorescent signal appeared in as little as 90 min. Unlike bulk assays, quantification in emulsion is robust and insensitive to fluctuations in environmental conditions (e.g., temperature). Power-free emulsification using gravity-driven flow in the absence of syringe pumps and portable fluorescence imaging solutions makes this technology promising for use at the point of care in low-resource environments. This droplet-based phage enumeration method could accelerate and simplify point-of-care detection of the pathogens for which reporter bacteriophages have been developed.

  8. Effects of surface wettability and roughness of microchannel on flow behaviors of thermo-responsive microspheres therein during the phase transition.

    Science.gov (United States)

    Zhou, Ming-Yu; Xie, Rui; Yu, Ya-Lan; Chen, Gang; Ju, Xiao-Jie; Yang, Lihua; Liang, Bin; Chu, Liang-Yin

    2009-08-01

    The flow characteristics of monodisperse thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) microspheres during the phase transition in microchannels with different surface wettabilities and roughnesses are investigated systematically. Glass microchannels are modified by hydroxylation treatment to achieve hydrophilic surface, by self-assembly of chlorotrimethylsilane to realize hydrophobic surface, and by coating with silica nanoparticles to generate rough surface. The phase transition of PNIPAM microspheres in microchannels is induced by local heating. The results show that the surface wettability and roughness of microchannel significantly affect the flow behaviors of PNIPAM microspheres during the phase transition. It is much easier for the PNIPAM microspheres in microchannel with hydrophobic surface to stop right after the phase transition than those in microchannel with hydrophilic surface, and it is also much easier for the PNIPAM microspheres in microchannel with rough surface to stop right after the phase transition than those in microchannel with smooth surface. These results indicate that hydrophobic and rough surface properties of the microchannel can enhance the site-specific targeting of PNIPAM microspheres caused by the phase transition. The results in this study provide valuable information for the application of thermo-responsive drug carriers in site-specific targeting therapy.

  9. Polystyrene Based Silver Selective Electrodes

    Directory of Open Access Journals (Sweden)

    Shiva Agarwal

    2002-06-01

    Full Text Available Silver(I selective sensors have been fabricated from polystyrene matrix membranes containing macrocycle, Me6(14 diene.2HClO4 as ionophore. Best performance was exhibited by the membrane having a composition macrocycle : Polystyrene in the ratio 15:1. This membrane worked well over a wide concentration range 5.0×10-6–1.0×10-1M of Ag+ with a near-Nernstian slope of 53.0 ± 1.0 mV per decade of Ag+ activity. The response time of the sensor is <15 s and the membrane can be used over a period of four months with good reproducibility. The proposed electrode works well in a wide pH range 2.5-9.0 and demonstrates good discriminating power over a number of mono-, di-, and trivalent cations. The sensor has also been used as an indicator electrode in the potentiometric titration of silver(II ions against NaCl solution. The sensor can also be used in non-aqueous medium with no significant change in the value of slope or working concentration range for the estimation of Ag+ in solution having up to 25% (v/v nonaqueous fraction.

  10. Coarse graining of polystyrene sulfonate

    Science.gov (United States)

    Perahia, Dvora; Agrawal, Anupriya; Grest, Gary S.

    2015-03-01

    Capturing large length scales in soft matter while retaining atomistic properties is imperative to computational studies. Here we develop a new coarse-grained model for polystyrene sulfonate (PSS) that often serves as a model system because of its narrow molecular weight distribution and defined degree of sulfonation. Four beads are used to represent polymer where the backbone, the phenyl group, and the sulfonated group are each represented by a different bead and the fourth one represents counterion, which is sodium in our case. Initial atomistic simulations of PSS melt with sulfonation levels of 2-10%, with a dielectric constant ɛ = 1 revealed a ``locked'' phase where motion of the polymer is limited. Dielectric constant of ɛ = 5 was used to accelerate the dynamics. Bonded interactions were obtained using Boltzmann inversion on the bonded distributions extracted from atomistic simulation. Non-bonded interaction of polystyrene monomer was taken from our previous work and potential of mean force was used as the initial guess for interaction of the ionic beads. This set of potential was subsequently iterated to get a good match with radial distribution functions. This potential and its transferability across dielectric constants and temperatures will be presented. Grant DE-SC007908.

  11. Radiation modified high impact polystyrene

    Science.gov (United States)

    Jelčić, Želimir; Ranogajec, Franjo

    2012-09-01

    The purpose of applying high energy (ionising) radiation with absorbed doses up to 1 MGy was to achieve controllable changes in mechanical properties of high impact polystyrene (PS-HI) and, at the same time, to investigate the possibility of using reprocessed irradiated polymeric material. Dielectric relaxation of a radiation modified high impact polystyrene (PS-HI) has been investigated by the time dependence of charging and discharging current. The transient currents for the irradiated PS-HI were well approximated by the power function of the logarithm of time and related to the fractal dimension. It was also shown that yield strength and tensile strength increase while elongation at break decreases with increasing absorbed dose. The specimen prepared by a post-irradiation moulding gave higher melt flow rate than those of specimen formed before irradiation. These results indicate that after radiation the system of PS-HI is reprocessable. It is concluded that an oxygen environment at the beginning of irradiation leads to enhanced chain scission at the expense of crosslinks via peroxide formation and causes oxidative degradation of the main polymer chain of irradiated PS-HI at a low absorbed dose. However, at higher absorbed doses the quasi-inert environment has been established and crosslinking, due to recombination of macroradicals, is dominant.

  12. Polystyrene calorimeter for electron beam dose measurements

    DEFF Research Database (Denmark)

    Miller, A.

    1995-01-01

    Calorimeters from polystrene have been constructed for dose measurement at 4-10 MeV electron accelerators. These calorimeters have been used successfully for a few years, and polystyrene calorimeters for use at energies down to 1 MeV and being tested. Advantage of polystyrene as the absorbing...

  13. Monitoring photonic nanojets from microsphere arrays by femtosecond laser ablation of thin films.

    Science.gov (United States)

    Grojo, D; Charmasson, L; Pereira, A; Sentis, M; Delaporte, P

    2011-10-01

    By comparing finite-difference time-domain near field simulations and femtosecond laser ablation of thin films, we characterize in three dimensional-space photonic nanojets from microsphere arrays. We demonstrate periodic drilling of transparent films with thickness up to 100 nm (onto absorbing substrates) is feasible with 1-microm diameter silica spheres. Working with larger polystyrene spheres, the apparent increase of the propagation length of the photonic nanojets makes possible to drill films as thick as 500 nm. Interestingly, the lateral width of the produced craters can be maintained below 400 nm evidencing the low divergence of the nanojets. For backside illumination of the arrays, the ablation features are located at the top of the microspheres. We reveal field enhancements in and out the spheres as well as laser energy confinement at the particle substrate interface. The wide variety of features observed in the experiments open routes to fabricating nanomaterials.

  14. Thermal evolution of structure and photocatalytic activity in polymer microsphere templated TiO2 microbowls

    Science.gov (United States)

    Erdogan, Deniz Altunoz; Polat, Meryem; Garifullin, Ruslan; Guler, Mustafa O.; Ozensoy, Emrah

    2014-07-01

    Polystyrene cross-linked divinyl benzene (PS-co-DVB) microspheres were used as an organic template in order to synthesize photocatalytic TiO2 microspheres and microbowls. Photocatalytic activity of the microbowl surfaces were demonstrated both in the gas phase via photocatalytic NO(g) oxidation by O2(g) as well as in the liquid phase via Rhodamine B degradation. Thermal degradation mechanism of the polymer template and its direct influence on the TiO2 crystal structure, surface morphology, composition, specific surface area and the gas/liquid phase photocatalytic activity data were discussed in detail. With increasing calcination temperatures, spherical polymer template first undergoes a glass transition, covering the TiO2 film, followed by the complete decomposition of the organic template to yield TiO2 exposed microbowl structures. TiO2 microbowl systems calcined at 600 °C yielded the highest per-site basis photocatalytic activity. Crystallographic and electronic properties of the TiO2 microsphere surfaces as well as their surface area play a crucial role in their ultimate photocatalytic activity. It was demonstrated that the polymer microsphere templated TiO2 photocatalysts presented in the current work offer a promising and a versatile synthetic platform for photocatalytic DeNOx applications for air purification technologies.

  15. Microspheres and their methods of preparation

    Science.gov (United States)

    Bose, Anima B; Yang, Junbing

    2015-03-24

    Carbon microspheres are doped with boron to enhance the electrical and physical properties of the microspheres. The boron-doped carbon microspheres are formed by a CVD process in which a catalyst, carbon source and boron source are evaporated, heated and deposited onto an inert substrate.

  16. Fabrication of Si/SiO2 Superlattice Microwire Array Solar Cells Using Microsphere Lithography

    Directory of Open Access Journals (Sweden)

    Shigeru Yamada

    2016-01-01

    Full Text Available A fabrication process for silicon/silicon dioxide (Si/SiO2 superlattice microwire array solar cells was developed. The Si/SiO2 superlattice microwire array was fabricated using a microsphere lithography process with polystyrene particles. The solar cell shows a photovoltaic effect and an open-circuit voltage of 128 mV was obtained. The limiting factors of the solar cell performance were investigated from the careful observations of the solar cell structures. We also investigated the influence of the microwire array structure on light trapping in the solar cells.

  17. Floating microspheres: a review

    Directory of Open Access Journals (Sweden)

    Jagtap Yogesh Mukund

    2012-03-01

    Full Text Available Gastric emptying is a complex process, one that is highly variable and that makes in vivo performance of drug delivery systems uncertain. A controlled drug delivery system with prolonged residence time in the stomach can be of great practical importance for drugs with an absorption window in the upper small intestine. The main limitations are attributed to the inter- and intra-subject variability of gastro-intestinal (GI transit time and to the non-uniformity of drug absorption throughout the alimentary canal. Floating or hydrodynamically controlled drug delivery systems are useful in such applications. Various gastroretentive dosage forms are available, including tablets, capsules, pills, laminated films, floating microspheres, granules and powders. Floating microspheres have been gaining attention due to the uniform distribution of these multiple-unit dosage forms in the stomach, which results in more reproducible drug absorption and reduced risk of local irritation. Such systems have more advantages over the single-unit dosage forms. The present review briefly addresses the physiology of the gastric emptying process with respect to floating drug delivery systems. The purpose of this review is to bring together the recent literature with respect to the method of preparation, and various parameters affecting the performance and characterization of floating microspheres.O esvaziamento gástrico é um processo complexo, com elevada variabilidade e responsável pela incerteza do desempenho dos medicamentos in vivo. Dessa forma, os sistemas de liberação modificada de fármacos, com tempo de residência prolongado no estômago, em especial, considerando aqueles fármacos com janela de absorção na porção superior do intestino delgado, apresentam fundamental importância. As principais limitações relativas à absorção do fármaco são, no geral, atribuídas à variabilidade inter e intra-paciente do tempo de trânsito gastro-intestinal (GI e

  18. Advances in Microsphere Insulation Systems

    Science.gov (United States)

    Allen, M. S.; Baumgartner, R. G.; Fesmire, J. E.; Augustynowicz, S. D.

    2004-06-01

    Microsphere insulation, typically consisting of hollow glass bubbles, combines in a single material the desirable properties that other insulations only have individually. The material has high crush strength, low density, is noncombustible, and performs well in soft vacuum. Microspheres provide robust, low-maintenance insulation systems for cryogenic transfer lines and dewars. They also do not suffer from compaction problems typical of perlite that result in the necessity to reinsulate dewars because of degraded thermal performance and potential damage to its support system. Since microspheres are load bearing, autonomous insulation panels enveloped with lightweight vacuum-barrier materials can be created. Comprehensive testing performed at the Cryogenics Test Laboratory located at the NASA Kennedy Space Center demonstrated competitive thermal performance with other bulk materials. Test conditions were representative of actual-use conditions and included cold vacuum pressure ranging from high vacuum to no vacuum and compression loads from 0 to 20 psi. While microspheres have been recognized as a legitimate insulation material for decades, actual implementation has not been pursued. Innovative microsphere insulation system configurations and applications are evaluated.

  19. Synthesis of Hollow Silica Nanospheres by Sacrificial Polystyrene Templates for Thermal Insulation Applications

    Directory of Open Access Journals (Sweden)

    Linn Ingunn C. Sandberg

    2013-01-01

    Full Text Available Monodisperse polystyrene (PS spheres with controllable size have been synthesized by a straight forward and simple procedure. The as-synthesized PS spheres have a typical diameter ranging from ~180 nm to ~900 nm, where a reduced sphere size is obtained by increasing the polyvinylpyrrolidone (PVP/styrene weight ratio. The PS spheres function as sacrificial templates for the fabrication of hollow silica nanospheres (HSNSs for thermal insulation applications. By modifying the silica coating process, HSNSs with different surface roughness are obtained. All resulting HSNSs show typically a thermal conductivity of about 20 mW/(mK, indicating that the surface phonon scattering is probably not significant in these HSNS samples.

  20. Fabrication of flower-like tin/carbon composite microspheres as long-lasting anode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Tae-Woo [Department of Chemical Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Lim, Hyung-Seok [Department of WCU Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Park, Seong-Jin [Department of Chemical Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Sun, Yang-Kook [Department of WCU Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Suh, Kyung-Do, E-mail: kdsuh@hanyang.ac.kr [Department of Chemical Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of)

    2017-01-01

    In this work, we report the fabrication of the flower-like tin/carbon (Sn/C) composite microspheres using sulfonated semi-interpenetrating polystyrene (SPS) microspheres as a carbon precursor. The sulfonation degree of SPS has great effects on the resulting particle size, morphology, amount of introduced Sn, and the carbonization yield of the microspheres after heat treatment. The obtained Sn/C composite microspheres were characterized by scanning electron microscopy (SEM), focused-ion beam SEM, and X-ray diffraction. The flower-like Sn/C composite electrodes exhibited higher charge-discharge capacities than those of graphite as an anode material for a lithium ion battery. In addition, they show a long lasting cyclability, even through 400 cycles. - Highlights: • Tin nanocrystals are introduced in flower-like carbon spheres with many ripples. • Long lasting cyclability is exhibited at 1 C rate up to 400 cycles. • Tin content of composite spheres depends on chemical treatment of polymer microspheres.

  1. Polarization Dependent Whispering Gallery Modes in Microspheres

    Science.gov (United States)

    Adamovsky, Grigory (Inventor); Wrbanek, Susan Y. (Inventor)

    2016-01-01

    A tunable resonant system is provided and includes a microsphere that receives an incident portion of a light beam generated via a light source, the light beam having a fundamental mode, a waveguide medium that transmits the light beam from the light source to the microsphere, and a polarizer disposed in a path of the waveguide between the light source and the microsphere. The incident portion of the light beam creates a fundamental resonance inside the microsphere. A change in a normalized frequency of the wavelength creates a secondary mode in the waveguide and the secondary mode creates a secondary resonance inside the microsphere.

  2. Porous microsphere and its applications

    Directory of Open Access Journals (Sweden)

    Cai Y

    2013-03-01

    Full Text Available Yunpeng Cai,1,2* Yinghui Chen,3* Xiaoyun Hong,2 Zhenguo Liu,1 Weien Yuan2 1Department of Neurology, Xinhua Hospital affiliated to Shanghai Jiaotong University School of Medicine, 2School of Pharmacy, Shanghai JiaoTong University, 3Department of Neurology Jinshan Hospital, Fudan University, Shanghai, People's Republic of China *These authors contributed equally to this workAbstract: Porous microspheres have drawn great attention in the last two decades for their potential applications in many fields, such as carriers for drugs, absorption and desorption of substances, pulmonary drug delivery, and tissue regeneration. The application of porous microspheres has become a feasible way to address existing problems. In this essay, we give a brief introduction of the porous microsphere, its characteristics, preparation methods, applications, and a brief summary of existing problems and research tendencies.Keywords: pore, porosity, porogen, suspension polymerization, seed swelling, pulmonary drug delivery, tissue regeneration

  3. Spontaneous droplet formation techniques for monodisperse emulsions preparation – Perspectives for food applications

    NARCIS (Netherlands)

    Maan, A.A.; Schroën, C.G.P.H.; Boom, R.M.

    2011-01-01

    Spontaneous droplet formation through Laplace pressure differences is a simple method for making monodisperse emulsions and is claimed to be suited for shear and temperature sensitive products, and those requiring high monodispersity. Techniques belonging to this category include (grooved) microchan

  4. Low molecular weight block copolymers as plasticizers for polystyrene

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Karsten; Nielsen, Charlotte Juel; Hvilsted, Søren

    2005-01-01

    Polystyrene-b-alkyl, polystyrene-b-polybutadiene-b-polystyrene, and polystyrene-b-poly(propylene glycol)monotridecyl ether were synthesized using macro initiators and atom transfer radical polymerization or by esterifications of homopolymers. The aim was a maximum molecular weight of 4 kg...

  5. Microsphere Super-resolution Imaging

    CERN Document Server

    Wang, Zengbo

    2015-01-01

    Recently, it was discovered that microsphere can generate super-resolution focusing beyond diffraction limit. This has led to the development of an exciting super-resolution imaging technique -microsphere nanoscopy- that features a record resolution of 50 nm under white lights. Different samples have been directly imaged in high resolution and real time without labelling, including both non-biological (nano devices, structures and materials) and biological (subcellular details, viruses) samples. This chapter reviews the technique, which covers its background, fundamentals, experiments, mechanisms as well as the future outlook.

  6. Facile Preparation of Phosphotungstic Acid-Impregnated Yeast Hybrid Microspheres and Their Photocatalytic Performance for Decolorization of Azo Dye

    Directory of Open Access Journals (Sweden)

    Lan Chen

    2013-01-01

    Full Text Available Phosphotungstic acid (HPW-impregnated yeast hybrid microspheres were prepared by impregnation-adsorption technique through tuning pH of the aqueous yeast suspensions. The obtained products were characterized by field emission scanning electron microscopy (FE-SEM, energy dispersive spectrometry (EDS, X-ray diffraction (XRD, thermogravimetry-differential scanning calorimetry (TG-DSC, and ultraviolet-visible spectrophotometry (UV-Vis, respectively. FE-SEM and EDS ascertain that the HPW has been effectively introduced onto the surface of yeast, and the resulting samples retain ellipsoid shape, with the uniform size (length 4.5 ± 0.2 μm, width 3.0 ± 0.3 μm and good monodispersion. XRD pattern indicates that the main crystal structure of as-synthesized HPW@yeast microsphere is Keggin structure. TG-DTA states that the HPW in composites has better thermal stability than pure HPW. Fourier transform infrared spectroscopy (FT-IR elucidates that the functional groups or chemical bonds inherited from the pristine yeast cell were critical to the assembling of the composites. UV-Vis shows that the obtained samples have a good responding to UV light. The settling ability indicates that the hybrid microspheres possess an excellent suspension performance. In the test of catalytic activity, the HPW@yeast microsphere exhibits a high photocatalytic activity for the decoloration of Methylene blue and Congo red dye aqueous solutions, and there are a few activity losses after four cycles of uses.

  7. Hierarchical flower-like nickel(II) oxide microspheres with high adsorption capacity of Congo red in water.

    Science.gov (United States)

    Zheng, Yingqiu; Zhu, Bicheng; Chen, Hua; You, Wei; Jiang, Chuanjia; Yu, Jiaguo

    2017-10-15

    Monodispersed hierarchical flower-like nickel(II) oxide (NiO) microspheres were fabricated by a facile solvothermal reaction with the assistance of ethanolamine and a subsequent calcination process. The as-synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption isotherms, zeta potential measurement and Fourier transform infrared spectroscopy. Flower-like nickel(II) hydroxide microspheres with uniform diameters of approximate 6.3μm were obtained after the solvothermal reaction. After heat treatment at 350°C, the crystal phase transformed to NiO, but the hierarchical porous structure was maintained. The as-prepared microspheres exhibited outstanding performance for the adsorption of Congo red (CR), an anionic organic dye, from aqueous solution at circumneutral pH. The pseudo-second-order model can make a good description of the adsorption kinetics, while Langmuir model could well express the adsorption isotherms, with calculated maximum CR adsorption capacity of 534.8 and 384.6mgg(-1), respectively, for NiO and Ni(OH)2. The adsorption mechanism of CR onto the as-synthesized samples can be mainly attributed to electrostatic interaction between the positively charged sample surface and the anionic CR molecules. The as-prepared NiO microspheres are a promising adsorbent for CR removal in water treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Biofilm formation and partial biodegradation of polystyrene by the actinomycete Rhodococcus ruber: biodegradation of polystyrene.

    Science.gov (United States)

    Mor, Roi; Sivan, Alex

    2008-11-01

    Polystyrene, which is one of the most utilized thermoplastics, is highly durable and is considered to be non-biodegradable. Hence, polystyrene waste accumulates in the environment posing an increasing ecological threat. In a previous study we have isolated a biofilm-producing strain (C208) of the actinomycete Rhodococcus ruber that degraded polyethylene films. Formation of biofilm, by C208, improved the biodegradation of polyethylene. Consequently, the present study aimed at monitoring the kinetics of biofilm formation by C208 on polystyrene, determining the physiological activity of the biofilm and analyzing its capacity to degrade polystyrene. Quantification of the biofilm biomass was performed using a modified crystal violet (CV) staining or by monitoring the protein content in the biofilm. When cultured on polystyrene flakes, most of the bacterial cells adhered to the polystyrene surface within few hours, forming a biofilm. The growth of the on polystyrene showed a pattern similar to that of a planktonic culture. Furthermore, the respiration rate, of the biofilm, exhibited a pattern similar to that of the biofilm growth. In contrast, the respiration activity of the planktonic population showed a constant decline with time. Addition of mineral oil (0.005% w/v), but not non-ionic surfactants, increased the biofilm biomass. Extended incubation of the biofilm for up to 8 weeks resulted in a small reduction in the polystyrene weight (0.8% of gravimetric weight loss). This study demonstrates the high affinity of C208 to polystyrene which lead to biofilm formation and, presumably, induced partial biodegradation.

  9. Activity of Antimicrobial Silver Polystyrene Nanocomposites

    National Research Council Canada - National Science Library

    Palomba, M; Carotenuto, G; Cristino, L; Di Grazia, M. A; Nicolais, F; De Nicola, S

    2012-01-01

    .... In particular, an antiseptic material has been prepared by dissolving silver 1,5-cyclooctadiene-hexafluoroacetylacetonate in amorphous polystyrene, and the obtained solid solution has been heated for ca...

  10. A flame-resistant modified polystyrene

    Science.gov (United States)

    Karle, D. W.; Kratze, R. H.; Pacioren, K. L.

    1975-01-01

    Several modified polystyrenes have been developed that are self-extinguishing in air. Information is included in report that also describes molding and fabrication properties, toxicology, and thermal behavior of the polymers.

  11. Thermoplastic polyurethanes with TDI-based monodisperse hard segments

    NARCIS (Netherlands)

    De, D.; Araichimani, A.; ten Hoopen, Hermina W.M.; Gaymans, R.J.

    2009-01-01

    Polyurethanes with PTMO soft segments and toluene diisocyanate diamide as urethane segment were studied. The toluene diisocyanate diamide urethane segment was monodisperse in length. The soft segment length was changed by extending PTMO with TDI units to a soft segment length varying from 2 250 to

  12. Highly monodisperse bismuth nanoparticles and their three-dimensional superlattices.

    Science.gov (United States)

    Yarema, Maksym; Kovalenko, Maksym V; Hesser, Günter; Talapin, Dmitri V; Heiss, Wolfgang

    2010-11-01

    A simple and reproducible synthesis of highly monodisperse and ligand-protected bismuth nanoparticles (Bi NPs) is reported. The size of the single-crystalline and spherically shaped NPs is controlled between 11 and 22 nm mainly by the reaction temperature. The high uniformity of the NPs allows their self-assembly into long-range-ordered two- and three-dimensional superstructures.

  13. A general approach for monodisperse colloidal perovskites, Chemistry of Materials

    NARCIS (Netherlands)

    Demirors, A.F.; Imhof, A.

    2009-01-01

    We describe a novel general method for synthesizing monodisperse colloidal perovskite particles at room temperature by postsynthesis addition of metal hydroxides to amorphous titania colloids. In previous work, we used titania particles to synthesize homogenously mixed silica-titania composite parti

  14. Polymer microspheres with structured surfaces

    NARCIS (Netherlands)

    Wagdare, N.A.; Baggerman, J.; Marcelis, A.T.M.; Boom, R.M.; Rijn, van C.J.M.

    2011-01-01

    Microspheres from polymethyl methacrylate (PMMA) and Eudragit FS 30D (a commercial copolymer of poly(methyl acrylate-co-methyl methacrylate-co-methacrylic acid) 7:3:1) were prepared using microsieve emulsification. A mixture of these polymers in dichloromethane (DCM) was dispersed into water, leadin

  15. Development of Risperidone PLGA Microspheres

    Directory of Open Access Journals (Sweden)

    Susan D’Souza

    2014-01-01

    Full Text Available The aim of this study was to design and evaluate biodegradable PLGA microspheres for sustained delivery of Risperidone, with an eventual goal of avoiding combination therapy for the treatment of schizophrenia. Two PLGA copolymers (50 : 50 and 75 : 25 were used to prepare four microsphere formulations of Risperidone. The microspheres were characterized by several in vitro techniques. In vivo studies in male Sprague-Dawley rats at 20 and 40 mg/kg doses revealed that all formulations exhibited an initial burst followed by sustained release of the active moiety. Additionally, formulations prepared with 50 : 50 PLGA had a shorter duration of action and lower cumulative AUC levels than the 75 : 25 PLGA microspheres. A simulation of multiple dosing at weekly or 15-day regimen revealed pulsatile behavior for all formulations with steady state being achieved by the second dose. Overall, the clinical use of Formulations A, B, C, or D will eliminate the need for combination oral therapy and reduce time to achieve steady state, with a smaller washout period upon cessation of therapy. Results of this study prove the suitability of using PLGA copolymers of varying composition and molecular weight to develop sustained release formulations that can tailor in vivo behavior and enhance pharmacological effectiveness of the drug.

  16. Optical trapping of coated microspheres

    NARCIS (Netherlands)

    Bormuth, V.; Jannasch, A.; Ander, M.; van Kats, C.M.; van Blaaderen, A.; Howard, J.; Schäffer, E.

    2008-01-01

    In an optical trap, micron-sized dielectric particles are held by a tightly focused laser beam. The optical force on the particle is composed of an attractive gradient force and a destabilizing scattering force. We hypothesized that using anti-reflection-coated microspheres would reduce scattering a

  17. Template-free synthesis of hierarchical TiO2 hollow microspheres as scattering layer for dye-sensitized solar cells

    Science.gov (United States)

    Rui, Yichuan; Wang, Linlin; Zhao, Jiachang; Wang, Hongzhi; Li, Yaogang; Zhang, Qinghong; Xu, Jingli

    2016-04-01

    Hierarchical TiO2 hollow microspheres were synthesized by a 2-step process consisting of thermal hydrolysis and subsequent solvothermal reaction. Quasi-monodispersed solid TiO2 microspheres aggregated by amorphous particles were firstly obtained by the controlled thermal hydrolysis of titanium sulfate, and then the solid structures transformed to hollow ones and crystallized during the subsequent solvothermal treatment. SEM and TEM images of the samples revealed that the morphological evolution was in perfect accordance with the inside-out Ostwald ripening mechanism. The rich porosity and unique hierarchical hollow structure endow the TiO2 microspheres with a large specific surface area of 108.0 m2 g-1. As an effective anode material for dye-sensitized solar cells, TiO2 hollow microspheres showed good capability of dye adsorption and strong light scattering, leading to a comparable energy conversion efficiency to the commercial 18NR-T transparent titania. Finally, a high efficiency of 7.84% was achieved for the bi-layer DSSC by coating the hollow microspheres on top of the 18NR-T titania as the light scattering layer.

  18. Characterization of silver/polystyrene nanocomposites prepared by in situ bulk radical polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Vukoje, Ivana D., E-mail: ivanav@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Vodnik, Vesna V., E-mail: vodves@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Džunuzović, Jasna V., E-mail: jasnav2002@googlemail.com [Institute of Chemistry, Technology and Metallurgy (ICTM)-Center of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia); Džunuzović, Enis S., E-mail: edzunuzovic@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade (Serbia); Marinović-Cincović, Milena T., E-mail: milena@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Jeremić, Katarina, E-mail: kjeremic@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade (Serbia); Nedeljković, Jovan M., E-mail: jovned@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia)

    2014-01-01

    Graphical abstract: - Highlights: • Synthesis and characterization of polystyrene nanocomposites based on Ag nanoparticles. • The glass transition temperature decreased in nanocomposites with respect to the pure polymer. • Resistance of the polymer to thermal degradation enhanced with Ag nanoparticles content. - Abstract: Nanocomposites (NCs) with different content of silver nanoparticles (Ag NPs) embeded in polystyrene (PS) matrix were prepared by in situ bulk radical polymerization. The nearly monodisperse Ag NPs protected with oleylamine were synthesized via organic solvo-thermal method and further used as a filler. The as-prepared spherical Ag NPs with diameter of 7.0 ± 1.5 nm were well dispersed in the PS matrix. The structural properties of the resulting Ag/PS NCs were characterized by transmission electron microscope (TEM) and Fourier transform infrared (FTIR) spectroscopy, while optical properties were characterized using optical absorption measurements. The gel permeation chromatography (GPC) measurements showed that the presence of Ag NPs stabilized with oleylamine has no influence on the molecular weight and polydispersity of the PS matrix. The influence of silver content on the thermal properties of Ag/PS NCs was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results indicated that resistance of PS to thermal degradation was improved upon incorporation of Ag NPs. The Ag/PS NCs have lower glass transition temperatures than neat PS because loosely packed oleylamine molecules at the interface caused the increase of free volume and chain segments mobility near the surface of Ag NPs.

  19. Dynamics of Sulfonated Polystyrene Copolymers and Ionomers using Broadband Dielectric Spectroscopy

    Science.gov (United States)

    Atorngitjawat, Pornpen; Runt, James

    2006-03-01

    The dynamics of sulfonated polystyrene (SPS) copolymers in acid and neutralized forms were investigated using broadband dielectric relaxation spectroscopy. SPS copolymers were synthesized by sulfonation of a monodisperse polystyrene to 1 and 7 mol %. Neutralization was achieved by exchanging the protons of the acid functionality with Na, Cs and Zn cations. Multiple relaxation processes were observed above the glass transition temperature of the neutralized and unneutralized materials. For the unneutralized copolymers, a `chemical relaxation' was observed at temperatures above the segmental process, arising from the presence of hydrogen bonding. For the ionomers, a Maxwell-Wagner-Sillars process was observed due to the presence of ionic clusters. The `chemical relaxation' followed Arrhenius behavior and its relaxation strength decreased significantly with increasing temperature. The relaxation times of the MWS process of all ionomers followed a VFT form. A local relaxation in the glassy state was observed for unneutalized copolymers and ionomers neutralized with monovalent cations, while it was suppressed for ionomers neutralized with divalent cations.

  20. Scalable synthesis of mesoporous titania microspheres via spray-drying method.

    Science.gov (United States)

    Pal, Manas; Wan, Li; Zhu, Yongheng; Liu, Yupu; Liu, Yang; Gao, Wenjun; Li, Yuhui; Zheng, Gengfeng; Elzatahry, Ahmed A; Alghamdi, Abdulaziz; Deng, Yonghui; Zhao, Dongyuan

    2016-10-01

    Mesoporous TiO2 has several potential applications due to its unique electronic and optical properties, although its structures and morphologies are typically difficult to tune because of its uncontrollable and fast sol-gel reaction. In this study we have coupled the template-directed-sol-gel-chemistry with the low-cost, scalable, and environmentally benign aerosol (spray-drying) one-pot preparation technique for the fabrication of hierarchically mesoporous TiO2 microspheres and Fe3O4@mesoporous TiO2-x microspheres in a large scale. Parameters during the pre-hydrolysis and spray-drying treatment were varied to successfully control the bead diameter, morphology, monodispersity, surface area and pore size for improving their effectiveness for better application. Unlike to the previous aerosol synthetic approaches, where mainly quite a high temperature gradient with the strict control of spray-drying precursor concentration is implied, our strategy is lying on comparatively low drying temperature with an additional post-ultrasonication (further hydrolysis and condensation) route of the pre-calcined TiO2 samples. As-synthesized mesoporous microspheres have a size distribution from 500nm to 5μm, specific surface areas ranging from 150 to 162m(2)g(-1) and mean pore sizes of several nanometers (4-6nm). Further Fe3O4@mesoporous TiO2-x microspheres were observed to show remarkable selective phosphopeptide-enrichment activity which might have significant importance in disease diagnosis and other biomedical applications.

  1. Synthesis and Band Gap Control in Three-Dimensional Polystyrene Opal Photonic Crystals

    Institute of Scientific and Technical Information of China (English)

    LIU Ye; ZHENG Zhong-Yu; QIN Fei; ZHOU Fei; ZHOU Chang-Zhu; ZHANG Dao-Zhong; MENG Qing-Bo; LI Zhi-Yuan

    2008-01-01

    High-quality three-dimensional polystyrene opal photonic crystals are fabricated by vertical deposition method.The transmission properties with different incident angles and different composite refractive index contrasts are experimentally and theoretically studied. Good agreement between the experiment and theory is achieved. We find that with the increasing incident angle, the gap position shifts to the short wavelength (blue shift) and the gap becomes shallower; and with the increase of refractive index of the opal void materials and decrease the contrast of refractive index, the gap position shifts to the long wavelength (red shift). At the same time, we observe the swelling effects when the sample is immerged in the solutions with different refractive indices, which make the microsphere diameter in solution become larger than that in air. The understanding of band gap shift behaviour may be helpful in designing optical sensors and tunable photonic crystal ultrafast optical switches.

  2. Polystyrene latex separations by continuous flow electrophoresis on the Space Shuttle

    Science.gov (United States)

    Snyder, R. S.; Rhodes, P. H.; Miller, T. Y.; Micale, F. J.; Mann, R. V.

    1986-01-01

    The seventh mission of the Space Shuttle carried two NASA experiments in the McDonnell Douglas Astronautics Corporation continuous flow electrophoresis system. The objectives were to test the operation of continuous flow electrophoresis in a reduced gravity environment using stable particles with established electrokinetic properties and specifically to evaluate the influence of the electrical properties of the sample constituents on the resolution of the continuous flow electrophoretic device. Polystrene latex microspheres dispersed in a solution with three times the electrical conductivity of the curtain buffer separated with a significantly larger band spread compared to the second experiment under matched conductivity conditions. It is proposed that the sample of higher electrical conductivity distorted the electric field near the sample stream so that the polystyrene latex particles migrated toward the chamber walls where electroosmosis retarded and spread the sample.

  3. Noble Metal Nanoparticle-loaded Mesoporous Oxide Microspheres for Catalysis

    Science.gov (United States)

    Jin, Zhao

    reaction, I found that Pd nanoparticles supported on mesoporous TiO2 exhibit the best catalytic performance. The demonstrated low-cost and high-productivity preparation method can be extended to other catalysts, which can contain various metals and oxide substrates and will have high potential for industrial applications. Our preparation method also provides a platform for the studies of the synergetic catalytic effects between different oxide substrates and metals. I further fabricated hollow mesoporous microspheres containing differently shaped noble metal nanocrystals. Hollow structures are strongly desired in many applications because of their high pore volumes, surface areas, and possible light-trapping effect. In my study, the hollow structures were obtained by simply dispersing polystyrene (PS) nanospheres into the precursor solution for aerosol spray. The PS spheres were removed by thermal calcination to produce hollow mesoporous microspheres. In my first study, the noble metal salts were dissolved in the precursor solutions, and the noble metal nanoparticles were obtained through thermal calcination. In this way, the size and shape of the metal nanoparticles cannot be well controlled. In my second study, I first grew noble metal nanocrystals and then incorporated them into the oxide supports. This preparation route allowed me to incorporate metal nanocrystals with controlled sizes, shapes, and compositions into the oxide matrices. The metal nanocrystals I used in this experiment included Pd nanocubes, Au nanorods, and Au core--Pd shell nanorods. These nanocrystals were functionalized with thiol-terminated methoxypoly(ethylene glycol) . The surface functionalization allowed them to adsorb on the PS spheres. After thermal calcination, the noble metal nanocrystals were left inside and adsorbed on the inner surface of the hollow mesoporous metal oxide microspheres. I investigated the catalytic activities of the Pd nanocube-embedded hollow mesoporous TiO2 and ZrO2

  4. ERYTHROMYCIN POLYLACTIC ACID MICROSPHERES FOR LUNG TARGETING

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    AIM: To prepare polylactic acid microspheres of Erythromycin for Lung targeting.METHEDS: The orthogonal test design was used to optimize the technology,of preparation. Thecharacter of the microspheres, drug release in vitro, stability and tissue distribution were examinedRESULTS: The Erythromycin polylactic acid microspheres was regular in its morphology. Drugwas enveloped in microspheres but not physically mixed with PDLLA. The average particle size was11.65μn with over 94% of the microspheres being in the range of 5~20trn; The drug loading andthe incorporation efciency were 18% and 60% respectively. The microspheres were stable for threemonth at 4 ℃ and room temperature. The in vitro release properties could be expressed by theHiguchi's equation: y = 28.067 + 3.8515t11/2 (r = 0.9834). Comparing with injection, the drug inmicrospheres was more concentrated in lung tissue. CONCLUSION: Erythromycin polylactic acidmicrospheres showed significant sustained release and lung targeting.

  5. Magnetoresponsive Photonic Microspheres with Structural Color Gradient.

    Science.gov (United States)

    Lee, Seung Yeol; Choi, Jongkook; Jeong, Jong-Ryul; Shin, Jung H; Kim, Shin-Hyun

    2017-02-06

    Photonic Janus particles are created by alternately sputtering silica and titania on microspheres in order to obtain a structural color gradient. In addition, the microspheres are rendered magnetoresponsive. The Janus microspheres with optical and magnetic anisotropy enable on-demand control over orientation and structural color through manipulation of an external magnetic field, thereby being useful as active color pigments for reflection-mode displays.

  6. Microsphere assembly of TiO2 mesoporous nanosheets with highly exposed (101) facets and application in a light-trapping quasi-solid-state dye-sensitized solar cell

    Science.gov (United States)

    Tao, Xiyun; Ruan, Peng; Zhang, Xiang; Sun, Hongxia; Zhou, Xingfu

    2015-02-01

    The morphology of nano-titania has a significant effect on the photoelectric properties of dye-sensitized solar cells. In this study, microsphere assembly of a TiO2 mesoporous nanosheet constructed by nanocuboids was conducted via a simple hydrothermal process. The XRD pattern indicated that the hierarchical mesoporous microspheres are anatase phase with decreased (004) peaks. Raman spectrum shows enhanced Eg peaks at 143 and 638 cm-1 caused by the symmetric stretching vibration of O-Ti-O of the (101) crystalline facet in anatase TiO2. FESEM and TEM images show that well monodispersed TiO2 microspheres with a diameter of 2 μm are assembled by TiO2 mesoporous nanosheets with exposed (101) facets. The oriented attachment of TiO2 nanocuboids along the (101) direction leads to the formation of mesoporous titania nanosheets. The UV-Vis spectrum shows that the mesoporous TiO2 nanosheets have high scattering ability and light absorption by dye. Quasi-solid-state dye-sensitized solar cells that incorporate these microspheres into the top scattering layers exhibit a prominent improvement in the power conversion efficiency of 7.51%, which shows a 45.8% increase in the overall conversion efficiency when compared with the spine hierarchical TiO2 microspheres (5.15%). There is the potential application for microsphere assembly of mesoporous TiO2 nanosheets in quasi-solid-state dye-sensitized solar cells with excellent stability.

  7. A co-flow-focusing monodisperse microbubble generator

    KAUST Repository

    Zhang, Jiaming

    2014-02-14

    We use a simple and inexpensive microfluidic device, which is based on microscope glass slides and two tapered glass capillaries, to produce monodisperse microbubbles. The innermost capillary used for transporting the gas is inserted into the second capillary, with its 2 μm sharp tip aligned with the center of the converging-diverging throat of the second capillary. This configuration provides a small and smooth gas flow rate, and a high velocity gradient at the tube outlet. Highly monodisperse microbubbles with diameters ranging from 3.5 to 60 microns have been successfully produced at a rate of up to 40 kHz. A simple scaling law, which is based on the capillary number and liquid-to-gas flow rate ratio, successfully predicts the bubble size. © 2014 IOP Publishing Ltd.

  8. Synthesis and antimicrobial activity of monodisperse copper nanoparticles.

    Science.gov (United States)

    Kruk, Tomasz; Szczepanowicz, Krzysztof; Stefańska, Joanna; Socha, Robert P; Warszyński, Piotr

    2015-04-01

    Metallic monodisperse copper nanoparticles at a relatively high concentration (300 ppm CuNPs) have been synthesized by the reduction of copper salt with hydrazine in the aqueous SDS solution. The average particles size and the distribution size were characterized by Dynamic Light Scattering (DLS), Nanosight-Nanoparticle Tracking Analysis (NTA). The morphology and structure of nanoparticles were investigated using Scanning Electron Microscopy (SEM). The chemical composition of the copper nanoparticles was determined by X-ray Photoelectron Spectroscopy (XPS). Monodisperse copper nanoparticles with average diameter 50 nm were received. UV/vis absorption spectra confirmed the formation of the nanoparticles with the characteristic peak 550 nm. The antimicrobial studies showed that the copper nanoparticles had high activity against Gram-positive bacteria, standard and clinical strains, including methicillin-resistant Staphylococcus aureus, comparable to silver nanoparticles and some antibiotics. They also exhibited antifungal activity against Candida species. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Synthesis of Monodisperse Iron Oxide Nanoparticles without Surfactants

    Directory of Open Access Journals (Sweden)

    Xiao-Chen Yang

    2014-01-01

    Full Text Available Monodisperse iron oxide nanoparticles could be successfully synthesized with two kinds of precipitants through a precipitation method. As-prepared nanoparticles in the size around 10 nm with regular spherical-like shape were achieved by adjusting pH values. NaOH and NH3·H2O were used as two precipitants for comparison. The average size of nanoparticles with NH3·H2O precipitant got smaller and represented better dispersibility, while nanoparticles with NaOH precipitant represented better magnetic property. This work provided a simple method without using any organic solvents, organic metal salts, or surfactants which could easily obtain monodisperse nanoparticles with tunable morphology.

  10. Preparation and Characterization of Monodisperse Nickel Nanoparticles by Polyol Process

    Institute of Scientific and Technical Information of China (English)

    LI Peng; GUAN Jianguo; ZHANG Qingjie; ZHAO Wenyu

    2005-01-01

    Polymer-protected monodisperse nickel nanoparticles were synthesized by a modified polyol reduction method in the presence of poly ( N-vinyl- 2-pyrrolidone ). These nanoparticles were characterized by transmission electron microscopy (TEM), X- ray diffraction ( XRD ), selected area electron diffraction ( SAED ), as well as vibrating sample magnetometer (VSM). The experimental results show that the addition of PVP and the concentration of NaOH have strong influences on the size, agglomeration and uniformity of nanoparticles. In the presence of PVP and NaOH with low concentrations, monodisperse nickel nanoparticles with average diameters about 42 nm were obtained and characterized to be pure nickel crystalline with fcc structure. Secondary structures such as clusters, loops, and strings resulted from magnetic interactions between particles were observed. The chemical interaction between the PVP and nickel nanoparticles was found by FTIR. The saturation magnetization ( Ms ), remanent magnetization (Mr) and coercivity ( Hc ) of these nickel nanoparticles are lower than those of bulk nickel.

  11. Novel chitosan microsphere-templated microcapsules suitable for spontaneous loading of heparin

    Energy Technology Data Exchange (ETDEWEB)

    Shao Yingya; Zhu Baoqing; Li Juan; Liu Xinrong; Tan Xin [School of Life Science and Technology, Beijing Institute of Technology, Beijing 100081 (China); Yang Xinlin, E-mail: xlyang@bit.edu.cn [School of Life Science and Technology, Beijing Institute of Technology, Beijing 100081 (China)

    2009-04-30

    This report aimed to describe a novel type of core-shell-structured microcapsules suitable for spontaneous loading of anticoagulant heparin. Chitosan (CS) microspheres were fabricated by a sodium sulfate-based precipitation process. The microspheres were approximately 1 {mu}m in size and applied as templates for microcapsules prepared by the layer-by-layer (LbL) self-assembly technique. Polyelectrolytes including polyanion poly(styrene sulfonate) and polycation CS were alternately deposited on CS microsphere templates, monitored by flow cytometry and zeta potential analysis. Scanning electron microscopy, confocal laser scanning microscopy, fluorescence microscopy, flow cytometry and laser particle size analysis were used to characterize the microcapsules. The resulted microcapsules were about 1 {mu}m in average diameter, and allowed spontaneous loading of heparin through electrostatic interaction, with the encapsulation efficiency and loading capacity of 74.4% and 10.0%, respectively. Moreover, heparin could be released from the microcapsules in phosphate buffered saline at pH 7.4. It is suggested that the type of microcapsules may provide a new and effective system of heparin delivery for pharmaceutical use.

  12. Chitosan and metal salt coagulant impacts on Cryptosporidium and microsphere removal by filtration.

    Science.gov (United States)

    Brown, Trevor J; Emelko, Monica B

    2009-02-01

    Maintenance of appropriate chemical pretreatment is a critical component of ensuring proper filtration performance. Pilot-scale in-line filtration studies were performed to investigate the relative impacts of chitosan, alum, and FeCl(3) coagulation on the removal of Cryptosporidium parvum oocysts and oocyst-sized polystyrene microspheres by granular media filtration. Similar removals of oocysts and microspheres were achieved when optimal coagulant doses were utilized. Sub-optimal alum and FeCl(3) coagulation resulted in a deterioration filter effluent turbidity (0.2-0.3NTU) and total particle counts (30-100 total particles > or =2microm/mL) that were accompanied by reduced (by approximately 2-3-log) median oocyst and microsphere removals by filtration. At all doses investigated, chitosan coagulation resulted in excellent turbidity and particle reductions by filtration. Nonetheless, chitosan coagulation at doses of 0.1, 0.5, and 1.0mg/L did not result in appreciable improvements in C. parvum oocyst removal relative to complete coagulation failure (median oocyst removals were alum and FeCl(3) coagulation, but not chitosan coagulation.

  13. The encapsulation of an amphiphile into polystyrene microspheres of narrow size distribution

    Directory of Open Access Journals (Sweden)

    Pellach Michal

    2011-12-01

    Full Text Available Abstract Encapsulation of compounds into nano- or microsized organic particles of narrow size distribution is of increasing importance in fields of advanced imaging and diagnostic techniques and drug delivery systems. The main technology currently used for encapsulation of molecules within uniform template particles while retaining their size distribution is based on particle swelling methodology, involving penetration of emulsion droplets into the particles. The swelling method, however, is efficient for encapsulation only of hydrophobic compounds within hydrophobic template particles. In order to be encapsulated, the molecules must favor the hydrophobic phase of an organic/aqueous biphasic system, which is not easily achieved for molecules of amphiphilic character. The following work overcomes this difficulty by presenting a new method for encapsulation of amphiphilic molecules within uniform hydrophobic particles. We use hydrogen bonding of acid and base, combined with a pseudo salting out effect, for the entrapment of the amphiphile in the organic phase of a biphasic system. Following the entrapment in the organic phase, we demonstrated, using fluorescein and (antibiotic tetracycline as model molecules, that the swelling method usually used only for hydrophobes can be expanded and applied to amphiphilic molecules.

  14. Microstructuring of polymer films by femtosecond pulses through optically trapped polystyrene microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Astaf' ev, A A; Shakhov, A M; Sarkisov, Oleg M; Nadtochenko, V A

    2013-04-30

    We report the laser ablation of polymers by femtosecond (18 and 54 fs) pulses focused by 1 and 3.8 {mu}m diameter spherical microlenses, which are held by optical traps. It is shown that this technique allows one to produce surface structures with lateral dimensions up to {lambda}/6 (125 nm). It is found that the size of the structures depends on the diameter of the microlens; the highest spatial resolution is achieved by using 1 {mu}m diameter microlenses. (extreme light fields and their applications)

  15. The encapsulation of an amphiphile into polystyrene microspheres of narrow size distribution.

    Science.gov (United States)

    Pellach, Michal; Margel, Shlomo

    2011-12-06

    Encapsulation of compounds into nano- or microsized organic particles of narrow size distribution is of increasing importance in fields of advanced imaging and diagnostic techniques and drug delivery systems. The main technology currently used for encapsulation of molecules within uniform template particles while retaining their size distribution is based on particle swelling methodology, involving penetration of emulsion droplets into the particles. The swelling method, however, is efficient for encapsulation only of hydrophobic compounds within hydrophobic template particles. In order to be encapsulated, the molecules must favor the hydrophobic phase of an organic/aqueous biphasic system, which is not easily achieved for molecules of amphiphilic character.The following work overcomes this difficulty by presenting a new method for encapsulation of amphiphilic molecules within uniform hydrophobic particles. We use hydrogen bonding of acid and base, combined with a pseudo salting out effect, for the entrapment of the amphiphile in the organic phase of a biphasic system. Following the entrapment in the organic phase, we demonstrated, using fluorescein and (antibiotic) tetracycline as model molecules, that the swelling method usually used only for hydrophobes can be expanded and applied to amphiphilic molecules.

  16. Polystyrene Chain Growth from Di-End-Functional Polyolefins for Polystyrene-Polyolefin-Polystyrene Block Copolymers

    Directory of Open Access Journals (Sweden)

    Chung Sol Kim

    2017-10-01

    Full Text Available Triblock copolymers of polystyrene (PS and a polyolefin (PO, e.g., PS-block-poly(ethylene-co-1-butene-block-PS (SEBS, are attractive materials for use as thermoplastic elastomers and are produced commercially by a two-step process that involves the costly hydrogenation of PS-block-polybutadiene-block-PS. We herein report a one-pot strategy for attaching PS chains to both ends of PO chains to construct PS-block-PO-block-PS directly from olefin and styrene monomers. Dialkylzinc compound containing styrene moieties ((CH2=CHC6H4CH2CH22Zn was prepared, from which poly(ethylene-co-propylene chains were grown via “coordinative chain transfer polymerization” using the pyridylaminohafnium catalyst to afford di-end functional PO chains functionalized with styrene and Zn moieties. Subsequently, PS chains were attached at both ends of the PO chains by introduction of styrene monomers in addition to the anionic initiator Me3SiCH2Li·(pmdeta (pmdeta = pentamethyldiethylenetriamine. We found that the fraction of the extracted PS homopolymer was low (~20% and that molecular weights were evidently increased after the styrene polymerization (ΔMn = 27–54 kDa. Transmission electron microscopy showed spherical and wormlike PS domains measuring several tens of nm segregated within the PO matrix. Optimal tensile properties were observed for the sample containing a propylene mole fraction of 0.25 and a styrene content of 33%. Finally, in the cyclic tensile test, the prepared copolymers exhibited thermoplastic elastomeric properties with no breakage up over 10 cycles, which is comparable to the behavior of commercial-grade SEBS.

  17. Oyster reproduction is affected by exposure to polystyrene microplastics.

    Science.gov (United States)

    Sussarellu, Rossana; Suquet, Marc; Thomas, Yoann; Lambert, Christophe; Fabioux, Caroline; Pernet, Marie Eve Julie; Le Goïc, Nelly; Quillien, Virgile; Mingant, Christian; Epelboin, Yanouk; Corporeau, Charlotte; Guyomarch, Julien; Robbens, Johan; Paul-Pont, Ika; Soudant, Philippe; Huvet, Arnaud

    2016-03-01

    Plastics are persistent synthetic polymers that accumulate as waste in the marine environment. Microplastic (MP) particles are derived from the breakdown of larger debris or can enter the environment as microscopic fragments. Because filter-feeder organisms ingest MP while feeding, they are likely to be impacted by MP pollution. To assess the impact of polystyrene microspheres (micro-PS) on the physiology of the Pacific oyster, adult oysters were experimentally exposed to virgin micro-PS (2 and 6 µm in diameter; 0.023 mg·L(-1)) for 2 mo during a reproductive cycle. Effects were investigated on ecophysiological parameters; cellular, transcriptomic, and proteomic responses; fecundity; and offspring development. Oysters preferentially ingested the 6-µm micro-PS over the 2-µm-diameter particles. Consumption of microalgae and absorption efficiency were significantly higher in exposed oysters, suggesting compensatory and physical effects on both digestive parameters. After 2 mo, exposed oysters had significant decreases in oocyte number (-38%), diameter (-5%), and sperm velocity (-23%). The D-larval yield and larval development of offspring derived from exposed parents decreased by 41% and 18%, respectively, compared with control offspring. Dynamic energy budget modeling, supported by transcriptomic profiles, suggested a significant shift of energy allocation from reproduction to structural growth, and elevated maintenance costs in exposed oysters, which is thought to be caused by interference with energy uptake. Molecular signatures of endocrine disruption were also revealed, but no endocrine disruptors were found in the biological samples. This study provides evidence that micro-PS cause feeding modifications and reproductive disruption in oysters, with significant impacts on offspring.

  18. Oyster reproduction is affected by exposure to polystyrene microplastics

    Science.gov (United States)

    Sussarellu, Rossana; Suquet, Marc; Thomas, Yoann; Lambert, Christophe; Fabioux, Caroline; Pernet, Marie Eve Julie; Le Goïc, Nelly; Quillien, Virgile; Mingant, Christian; Epelboin, Yanouk; Corporeau, Charlotte; Guyomarch, Julien; Robbens, Johan; Paul-Pont, Ika; Soudant, Philippe; Huvet, Arnaud

    2016-01-01

    Plastics are persistent synthetic polymers that accumulate as waste in the marine environment. Microplastic (MP) particles are derived from the breakdown of larger debris or can enter the environment as microscopic fragments. Because filter-feeder organisms ingest MP while feeding, they are likely to be impacted by MP pollution. To assess the impact of polystyrene microspheres (micro-PS) on the physiology of the Pacific oyster, adult oysters were experimentally exposed to virgin micro-PS (2 and 6 µm in diameter; 0.023 mg·L−1) for 2 mo during a reproductive cycle. Effects were investigated on ecophysiological parameters; cellular, transcriptomic, and proteomic responses; fecundity; and offspring development. Oysters preferentially ingested the 6-µm micro-PS over the 2-µm-diameter particles. Consumption of microalgae and absorption efficiency were significantly higher in exposed oysters, suggesting compensatory and physical effects on both digestive parameters. After 2 mo, exposed oysters had significant decreases in oocyte number (−38%), diameter (−5%), and sperm velocity (−23%). The D-larval yield and larval development of offspring derived from exposed parents decreased by 41% and 18%, respectively, compared with control offspring. Dynamic energy budget modeling, supported by transcriptomic profiles, suggested a significant shift of energy allocation from reproduction to structural growth, and elevated maintenance costs in exposed oysters, which is thought to be caused by interference with energy uptake. Molecular signatures of endocrine disruption were also revealed, but no endocrine disruptors were found in the biological samples. This study provides evidence that micro-PS cause feeding modifications and reproductive disruption in oysters, with significant impacts on offspring. PMID:26831072

  19. Monodispersive CoPt Nanoparticles Synthesized Using Chemical Reduction Method

    Institute of Scientific and Technical Information of China (English)

    SHEN Cheng-Min; HUI Chao; YANG Tian-Zhong; XIAO Cong-Wen; CHEN Shu-Tang; DING Hao; GAO Hong-Jun

    2008-01-01

    @@ Monodispersive CoPt nanoparticles in sizes of about 2.2 nm are synthesized by superhydride reduction of CoCl2 and PtCl2 in diphenyl ether. The as-prepared nanoparticles show a chemically disordered A1 structure and are superparamagnetic. Thermal annealing transforms the A1 structure into chemically ordered L1o structure and the particles are ferromagnetic at room temperature.

  20. Monodisperse magnesium hydride nanoparticles uniformly self-assembled on graphene.

    Science.gov (United States)

    Xia, Guanglin; Tan, Yingbin; Chen, Xiaowei; Sun, Dalin; Guo, Zaiping; Liu, Huakun; Ouyang, Liuzhang; Zhu, Min; Yu, Xuebin

    2015-10-21

    Monodisperse MgH2 nanoparticles with homogeneous distribution and a high loading percent are developed through hydrogenation-induced self-assembly under the structure-directing role of graphene. Graphene acts not only as a structural support, but also as a space barrier to prevent the growth of MgH2 nanoparticles and as a thermally conductive pathway, leading to outstanding performance.

  1. Compression molding of aerogel microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Pekala, Richard W. (Pleasant Hill, CA); Hrubesh, Lawrence W. (Pleasanton, CA)

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50-800 kg/m.sup.3 (0.05-0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization.

  2. Compression molding of aerogel microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Pekala, R.W.; Hrubesh, L.W.

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner is disclosed. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50--800 kg/m{sup 3} (0.05--0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization. 4 figs.

  3. The Study of the Microbes Degraded Polystyrene

    Directory of Open Access Journals (Sweden)

    Zhi-Long Tang

    2017-01-01

    Full Text Available Under the observation that Tenebrio molitor and Zophobas morio could eat polystyrene (PS, we setup the platform to screen the gut microbes of these two worms. To take advantage of that Tenebrio molitor and Zophobas morio can eat and digest polystyrene as its diet, we analyzed these special microbes with PS plate and PS turbidity system with time courses. There were two strains TM1 and ZM1 which isolated from Tenebrio molitor and Zophobas morio, and were identified by 16S rDNA sequencing. The results showed that TM1 and ZM1 were cocci-like and short rod shape Gram-negative bacteria under microscope. The PS plate and turbidity assay showed that TM1 and ZM1 could utilize polystyrene as their carbon sources. The further study of PS degraded enzyme and cloning warrants our attention that this platform will be an excellent tools to explore and solve this problem.

  4. Facile Synthesis of Monodisperse CdS Nanocrystals via Microreaction

    Directory of Open Access Journals (Sweden)

    Zhou Xinggui

    2009-01-01

    Full Text Available Abstract CdS-based nanocrystals (NCs have attracted extensive interest due to their potential application as key luminescent materials for blue and white LEDs. In this research, the continuous synthesis of monodisperse CdS NCs was demonstrated utilizing a capillary microreactor. The enhanced heat and mass transfer in the microreactor was useful to reduce the reaction temperature and residence time to synthesize monodisperse CdS NCs. The superior stability of the microreactor and its continuous operation allowed the investigation of synthesis parameters with high efficiency. Reaction temperature was found to be a key parameter for balancing the reactivity of CdS precursors, while residence time was shown to be an important factor that governs the size and size distribution of the CdS NCs. Furthermore, variation of OA concentration was demonstrated to be a facile tuning mechanism for controlling the size of the CdS NCs. The variation of the volume percentage of OA from 10.5 to 51.2% and the variation of the residence time from 17 to 136 s facilitated the synthesis of monodisperse CdS NCs in the size range of 3.0–5.4 nm, and the NCs produced photoluminescent emissions in the range of 391–463 nm.

  5. Microspheres in Plasma Display Panels

    Science.gov (United States)

    2006-01-01

    Filling small bubbles of molten glass with gases is just as difficult as it sounds, but the technical staff at NASA is not known to shy away from a difficult task. When Microsphere Systems, Inc. (MSI), of Ypsilanti, Michigan, and Imaging Systems Technology, Inc. (IST), of Toledo, Ohio, were trying to push the limits of plasma displays but were having difficulty with the designs, NASA s Glenn Garrett Morgan Commercialization Initiative (GMCI) assembled key personnel at Glenn Research Center and Ohio State University for a brainstorming session to come up with a solution for the companies. They needed a system that could produce hollow, glass micro-sized spheres (microspheres) that could be filled with a variety of gasses. But the extremely high temperature required to force the micro-sized glass bubbles to form at the tip of a metal nozzle resulted in severe discoloration of the microspheres. After countless experiments on various glass-metal combinations, they had turned to the GMCI for help. NASA experts in advanced metals, ceramics, and glass concluded that a new design approach was necessary. The team determined that what was needed was a phosphate glass composition that would remain transparent, and they went to work on a solution. Six weeks later, using the design tips from the NASA team, Tim Henderson, president of MSI, had designed a new system in which all surfaces in contact with the molten glass would be ceramic instead of metal. Meanwhile, IST was able to complete a Phase I Small Business Innovation Research (SBIR) grant supported by the National Science Foundation (NSF) and supply a potential customer with samples of the microspheres for evaluation as filler materials for high-performance insulations.

  6. Design of nanoengineered hybrid PVA/PNIPAm/CaCl2/SiO2-Polystyrene (PSt) colloidal crystal hydrogel coatings that sweat/rehydrate H2O from the atmosphere to give sustainable cooling and self-indicate their state

    Science.gov (United States)

    Eloi, Jean-Charles; Worsley, Myles P.; Sermon, Paul A.; Healy, William; Dimech, Christine

    2016-09-01

    The potential for nanoengineering hybrid PVA hydrogel and hydrogel microsphere optical coatings is demonstrated with fine-tuning by the addition of (i) PNIPAm domains, (ii) water-hunting humectant CaCl2, and (ii) polystyrene or SiO2 colloidal crystals. The design and application onto substrates of the hydrogel scaffold is described. The addition of a temperature-triggered component as well as humectant and NIR reflectors are reported. The hybrid hydrogels appeared effective in sustainable adsorption cooling technology (ACT) over sustained periods. It is shown that the thermoresponsive (PNIPAm) domains act as an extra reserve, sweating water above 305K, prolonging the controlled release of water. It is also reported that the addition of humectant is crucial for the natural re-hydration of the hydrogels. For the moment PNIPAm microspheres have only short- lived ACT properties. Finally, coating with microspheres (MSs) in hydrogels produces a visible-NIR reflector effect that may allow optical feedback on ACT.

  7. Simulative calculation of bromo-polystyrene mechanical properties

    CERN Document Server

    Wang Chao; Tang Yong Jian

    2002-01-01

    The non-crystal model of polystyrene and bromo-polystyrene was established with the help of simulative software in the computer. DREIDING was chosen as force field and its parameters is modified according to the published data. Based on the calculation results and other published data the mechanism properties of polystyrene and bromo-polystyrene, such as bulk module, Yong's module and Poisson's ratios, were discussed

  8. Glass microspheres for medical applications

    Science.gov (United States)

    Conzone, Samuel David

    Radioactive dysprosium lithium borate glass microspheres have been developed as biodegradable radiation delivery vehicles for the radiation synovectomy treatment of rheumatoid arthritis. Once injected into a diseased joint, the microspheres deliver a potent dose of radiation to the diseased tissue, while a non-uniform chemical reaction converts the glass into an amorphous, porous, hydrated dysprosium phosphate reaction product. The non-radioactive, lithium-borate component is dissolved from the glass (up to 94% weight loss), while the radioactive 165Dy reacts with phosphate anions in the body fluids, and becomes "chemically" trapped in a solid, dysprosium phosphate reaction product that has the same size as the un-reacted glass microsphere. Ethylene diamine tetraacetate (EDTA) chelation therapy can be used to dissolve the dysprosium phosphate reaction product after the radiation delivery has subsided. The dysprosium phosphate reaction product, which formed in vivo in the joint of a Sprague-Dawley rat, was dissolved by EDTA chelation therapy in 100 Gy) of localized beta radiation to a treatment site within the body, followed by complete biodegradability. The non-uniform reaction process is a desirable characteristic for a biodegradable radiation delivery vehicle, but it is also a novel material synthesis technique that can convert a glass to a highly porous materials with widely varying chemical composition by simple, low-temperature, glass/solution reaction. The reaction product formed by nonuniform reaction occupies the same volume as the un-reacted glass, and after drying for 1 h at 300°C, has a specific surface area of ≈200 m2/g, a pore size of ≈30 nm, and a nominal crushing strength of ≈10 MPa. Finally, rhenium glass microspheres, composed of micron-sized, metallic rhenium particles dispersed within a magnesium alumino borate glass matrix were produced by sintering ReO2 powder and glass frit at 1050°C. A 50 mg injection of radioactive rhenium glass

  9. POROUS WALL, HOLLOW GLASS MICROSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Sexton, W.

    2012-06-30

    Hollow Glass Microspheres (HGM) is not a new technology. All one has to do is go to the internet and Google{trademark} HGM. Anyone can buy HGM and they have a wide variety of uses. HGM are usually between 1 to 100 microns in diameter, although their size can range from 100 nanometers to 5 millimeters in diameter. HGM are used as lightweight filler in composite materials such as syntactic foam and lightweight concrete. In 1968 a patent was issued to W. Beck of the 3M{trademark} Company for 'Glass Bubbles Prepared by Reheating Solid Glass Particles'. In 1983 P. Howell was issued a patent for 'Glass Bubbles of Increased Collapse Strength' and in 1988 H. Marshall was issued a patent for 'Glass Microbubbles'. Now Google{trademark}, Porous Wall, Hollow Glass Microspheres (PW-HGMs), the key words here are Porous Wall. Almost every article has its beginning with the research done at the Savannah River National Laboratory (SRNL). The Savannah River Site (SRS) where SRNL is located has a long and successful history of working with hydrogen and its isotopes for national security, energy, waste management and environmental remediation applications. This includes more than 30 years of experience developing, processing, and implementing special ceramics, including glasses for a variety of Department of Energy (DOE) missions. In the case of glasses, SRS and SRNL have been involved in both the science and engineering of vitreous or glass based systems. As a part of this glass experience and expertise, SRNL has developed a number of niches in the glass arena, one of which is the development of porous glass systems for a variety of applications. These porous glass systems include sol gel glasses, which include both xerogels and aerogels, as well as phase separated glass compositions, that can be subsequently treated to produce another unique type of porosity within the glass forms. The porous glasses can increase the surface area compared to &apos

  10. Elongational viscosity of multiarm (Pom-Pom) polystyrene

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.; Almdal, Kristoffer

    2006-01-01

    Two branched narrow molar mass distribution polystyrene melts have been synthesized: A multiarm A_nAA_n Pom-Pom polystyrene and AA_n asymmetric star polystyrene where n indicates the number of arms. The Pom-Pom and asymmetric star have molar masses 260 kg/mol and 255 kg/mol, respectively. The Pom...

  11. Influence of polystyrene and polyethylene packaging materials on food quality.

    NARCIS (Netherlands)

    Linssen, J.P.H.

    1992-01-01

    Polystyrene (PS) and polyethylene (PE) used for packaging of food were studied on their effect on product quality. Different types of PS were tested: General purpose polystyrene (GPPS), high impact polystyrene (HIPS, which contains a dispersed rubber phase) and several blends of these types. PS

  12. Elongational viscosity of multiarm (Pom-Pom) polystyrene

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.; Almdal, Kristoffer;

    2006-01-01

    Two branched narrow molar mass distribution polystyrene melts have been synthesized: A multiarm A_nAA_n Pom-Pom polystyrene and AA_n asymmetric star polystyrene where n indicates the number of arms. The Pom-Pom and asymmetric star have molar masses 260 kg/mol and 255 kg/mol, respectively. The Pom...

  13. Expanded Polystyrene Re-Expansion Analysis Following Impact Compression

    Science.gov (United States)

    2015-03-04

    USAARL Report No. 2015-08 Expanded Polystyrene Re-Expansion Analysis Following Impact Compression By Mark S. Adams Frederick Brozoski Katie...13 iv This page is intentionally left blank. 1 Introduction Expanded bead polystyrene (EPS) is widely...EPS energy attenuating liners typically have complex geometric shapes. However, the use of flat sheets of polystyrene facilitated the sample

  14. ERYTHROMYCIN POLYLACTIC ACID MICROSPHERES FOR LUNG TARGETING

    Institute of Scientific and Technical Information of China (English)

    YANGFan; YANBing; 等

    2002-01-01

    AIM:To prepare polylactiv acid microspheres of Erythromycin for Lung targeting.METHEDS:The orthogonal test design was used to optimize the technology of preparation.The character of the microspheres,drug release in vitro,stabiligy and tissue distribution were examined. RESULTS:The Erythromycin polylatic acid microspheres was regular in its morphology.Drug was enveloped in microspheres but not physically mixed with PDLLA.The average particle size was 11.65μm with over 94% of the microspheres being in the range of 5-20μm;The drug loading and the incorporation efficiency were 18% and 60% respectively.The microspheres were stable for three month at 4℃ and room temperature.The in vitro release properties could be expressed by the Higuchi′s equation:y=28.067+3.8515t1/2(r=0.9834).Comparing with injection,the drug in microspheres was more concentrated in lung tissue.CONLUSION:Erythromycin polylactic acid microspheres showed significant sustained release and lung targeting.

  15. Assembly of ordered magnetic microsphere arrays

    Science.gov (United States)

    Xu, Wanling; Ketterson, John

    2008-08-01

    We have developed a straightforward technique to assemble ordered arrays of magnetic microspheres on patterned thin Permalloy (Py) films deposited on the surface of a silicon wafer. Droplets containing micrometer-sized carboxyl paramagnetic microspheres are placed on a horizontally oriented wafer. The field produced by a permanent magnet placed under the wafer is rendered inhomogeneous by the patterned Py features and the resulting field gradients attract and hold the paramagnetic microspheres to these features. While the magnetic microspheres are being attracted to and secured on the pattered Permalloy features, a horizontal flow is created by a pipette, which also removes loose (unsecured) microspheres. By applying this technique to a cocktail of individually functionalized microspheres, a sensor could be realized, which will screen, in parallel, for a large number of targets per unit area. The ability to resolve individual microspheres is close to 100%. A desirable feature is that the substrate is reusable; removing the magnet allows an existing batch of microspheres, which may have lost sensitivity due to environmental exposure, to be flushed from the substrate and replaced with a new batch. The technique complements existing approaches in the field of microarrays widely used in immunoassay, DNA fragment detection, pathogen detection, and other applications in functional genomics and diagnostics.

  16. Microencapsulation and microspheres for food applications

    NARCIS (Netherlands)

    Sagis, L.M.C.

    2015-01-01

    This book provides an update on the latest developments, challenges, and opportunities in the highly expanding field of microencapsulation and microspheres for food applications, examining the various types of microspheres and microcapsules essential to those who need to develop stable and impermeab

  17. Dextran-based microspheres as controlled delivery systems for proteins

    NARCIS (Netherlands)

    Vlugt-Wensink, K.D.F.

    2007-01-01

    Dextran-based microspheres as controlled delivery systems for proteins Dextran based microspheres are investigated as controlled delivery system for proteins. Microspheres were prepared by polymerization of dex-HEMA in an aqueous two-phase system of dex-HEMA and PEG. Protein loaded microspheres are

  18. Inter-laboratory comparison on the size and stability of monodisperse and bimodal synthetic reference particles for standardization of extracellular vesicle measurements

    Science.gov (United States)

    Nicolet, Anaïs; Meli, Felix; van der Pol, Edwin; Yuana, Yuana; Gollwitzer, Christian; Krumrey, Michael; Cizmar, Petr; Buhr, Egbert; Pétry, Jasmine; Sebaihi, Noham; de Boeck, Bert; Fokkema, Vincent; Bergmans, Rob; Nieuwland, Rienk

    2016-03-01

    In future, measurements of extracellular vesicles in body fluids could become a standard diagnostic tool in medicine. For this purpose, reliable and traceable methods, which can be easily applied in hospitals, have to be established. Within the European Metrological Research Project (EMRP) ‘Metrological characterization of micro-vesicles from body fluids as non-invasive diagnostic biomarkers’ (www.metves.eu), various nanoparticle reference materials were developed and characterized. We present results of an international comparison among four national metrology institutes and a university hospital. The size distributions of five monodisperse and two bimodal spherical particle samples with diameters ranging from 50 nm to 315 nm made out of silica and polystyrene were compared. Furthermore, the stability of the samples was verified over a period of 18 months. While monodisperse reference particle samples above a certain size level lead to good agreements of the size measurements among the different methods, small and bimodal samples show the limitations of current ‘clinical’ methods. All samples proved to be stable within the uncertainty of the applied methods.

  19. Hydroxyapatite nanocrystal coating on biodegradable microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Masahiro [Department of Bioengineering, Advanced Medical Engineering Center, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565 (Japan); Furuzono, Tsutomu, E-mail: furuzono@ri.ncvc.go.jp [Department of Bioengineering, Advanced Medical Engineering Center, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565 (Japan)

    2010-10-15

    Nano-sized single crystals of calcined hydroxyapatite (HAp) were uniformly coated on poly(L-lactic acid) (PLLA) microspheres through the ionic interaction between calcium ions on the HAp nanocrystal and carboxyl groups on the PLLA microsphere. In order to coat the substrate with HAp nanocrystals through ionic interaction, the surfaces of the PLLA microspheres were hydrolyzed in an alkaline aqueous solution at pH 11.0 for 1 h at room temperature. The interaction between the HAp nanocrystals and the carboxyl groups originating from PLLA end groups was estimated by Fourier transform infrared spectroscopy. The alkali-treated PLLA microspheres were coated with HAp nanocrystals by immersing the microspheres in an ethanol dispersion of HAp nanocrystals followed by washing in an ultrasonic bath.

  20. Activity of Antimicrobial Silver Polystyrene Nanocomposites

    Directory of Open Access Journals (Sweden)

    M. Palomba

    2012-01-01

    Full Text Available A simple technique based on doping polymers with in situ generated silver nanoparticles (Ag/PS films has been developed. In particular, an antiseptic material has been prepared by dissolving silver 1,5-cyclooctadiene-hexafluoroacetylacetonate in amorphous polystyrene, and the obtained solid solution has been heated for ca. 10 s at a convenient temperature (180°C. Under such conditions the metal precursor decomposes producing silver atoms that diffuse into the polymer and clusterize. The antimicrobial characteristics of the resulting polystyrene-based material have been accurately evaluated toward Escherichia coli (E. coli comparing the cytotoxicity effect of 10 wt.% and 30 wt.% (drastic and mild annealing silver-doped polystyrene to the corresponding pure micrometric silver powder. Two different bacterial viability assays were performed in order to demonstrate the cytotoxic effect of Ag/PS films on cultured E. coli: (1 turbidimetric determination of optical density; (2 BacLight fluorescence-based test. Both methods have shown that silver-doped polystyrene (30 wt.% provides higher antibacterial activity than pure Ag powder, under similar concentration and incubation conditions.

  1. Polyethylene glycol-grafted polystyrene particles

    NARCIS (Netherlands)

    Meng, Fenghua; Engbers, Gerard H.M.; Feijen, Jan

    2004-01-01

    Densely pegylated particles that can serve as a model system for artificial cells were prepared by covalently grafting amino polyethylene glycol (PEG, molecular weight 3400 or 5000) onto carboxyl polystyrene particles (PS-COOH) using carbodiimide chemistry. PEG-modified particles (PS-PEG) were chara

  2. Highly regenerable mussel-inspired Fe₃O₄@polydopamine-Ag core-shell microspheres as catalyst and adsorbent for methylene blue removal.

    Science.gov (United States)

    Xie, Yijun; Yan, Bin; Xu, Haolan; Chen, Jian; Liu, Qingxia; Deng, Yonghong; Zeng, Hongbo

    2014-06-11

    We report a facile method to synthesize Fe3O4@polydopamine (PDA)-Ag core-shell microspheres. Ag nanoparticles (NPs) are deposited on PDA surfaces via in situ reduction by mussel-inspired PDA layers. High catalytic activity and fast adsorption of a model dye methylene blue (MB) at different pH values are achieved mainly due to the presence of monodisperse Ag NPs and electrostatic interactions between PDA and MB. The as-prepared Fe3O4@PDA-Ag microspheres also show high cyclic stability (>27 cycles), good acid stability, and fast regeneration ability, which can be achieved efficiently within several minutes by using NaBH4 as the desorption agent, showing great potentials in a wide range of applications.

  3. Preparation of core-shell Fe{sub 3}O{sub 4}/SiO{sub 2} microspheres as adsorbents for purification of DNA

    Energy Technology Data Exchange (ETDEWEB)

    Gai Ligang; Li Zhili; Jiang Haihui; Han Xiaoyun; Ma Wanyong [Shandong Provincial Key Laboratory of Fine Chemicals, School of Chemical Engineering, Shandong Institute of Light Industry, Jinan 250353 (China); Hou Yunhua, E-mail: liganggai@yahoo.co [Shandong Provincial Key Laboratory of Microbial Engineering, School of Food Science and Bioengineering, Shandong Institute of Light Industry, Jinan 250353 (China)

    2010-11-10

    Nearly monodisperse core-shell Fe{sub 3}O{sub 4}/SiO{sub 2} microspheres have been prepared via a glycol reduction method followed by a modified Stoeber process. The thickness of the silica shells can be tuned in the range 33-53 nm by varying the amount of tetraethyl silicate (TEOS) during syntheses. The magnetic composite microspheres were characterized with XRD, XPS, FTIR, TEM, ICP-OES and VSM, and further tested as adsorbents for purification of plasmid DNA from Escherichia coli DH5{alpha} cells. The magnetic purification of plasmid DNA leads to satisfying integrity, yield and purity in comparison with those isolated by the traditional phenol-chloroform extraction.

  4. Biofunctionalization of silica microspheres for protein separation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Binjie [Institute of Immunology, Henan University, Kaifeng 475004 (China); Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Zou, Xueyan [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Zhao, Yanbao, E-mail: yanbaozhao@126.com [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Sun, Lei [Institute of Immunology, Henan University, Kaifeng 475004 (China); Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Li, Shulian [Institute of Immunology, Henan University, Kaifeng 475004 (China)

    2013-07-01

    Mercapto-silica (SiO{sub 2}–SH) microspheres were prepared via direct hydrolysis of 3-mercaptopropyltrimethoxysilane (MPS) in a basic aqueous solution. The content of surface thiol group (-SH) of SiO{sub 2}–SH microspheres was measured by Ellman's reagent method and X-ray photoelectron spectroscopy (XPS) and the content of surface thiol group of SiO{sub 2}–SH microspheres is strongly dependent on the reaction conditions. The thermal stability of SiO{sub 2}–SH microspheres was evaluated by thermogravimetric (TG) analysis, which tended to reduce with the increase of content of surface thiol groups. SiO{sub 2}–SH microspheres can be easily modified with reduced glutathione (GSH) to generate SiO{sub 2}–GSH microspheres for the affinity separation of Glutathione S-transferase (GST). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to examine the validity of the separation procedure. The results showed that SiO{sub 2}–GSH microspheres were efficient in GST affinity separation from mixed proteins. - Graphical abstract: The prepared SiO{sub 2}–SH microsphere binding reduced glutathione (SiO{sub 2}–GSH) as affinity precipitation support can capture selectively Glutathione S-transferase (GST) from mixed protein solution. Highlights: ► SiO{sub 2}–SH microspheres were prepared in water using one-pot synthesis. ► The content of surface -SH was investigated by Ellman method and XPS spectra. ► The ratio of -SH to mass strongly depends on the reaction conditions. ► SiO{sub 2}–SH microspheres were biofunctionalized by glutathione. ► SiO{sub 2}–GSH can be used to capture selectively Glutathione S-transferase.

  5. Morphologically and size uniform monodisperse particles and their shape-directed self-assembly

    Science.gov (United States)

    Collins, Joshua E.; Bell, Howard Y.; Ye, Xingchen; Murray, Christopher Bruce

    2015-11-17

    Monodisperse particles having: a single pure crystalline phase of a rare earth-containing lattice, a uniform three-dimensional size, and a uniform polyhedral morphology are disclosed. Due to their uniform size and shape, the monodisperse particles self assemble into superlattices. The particles may be luminescent particles such as down-converting phosphor particles and up-converting phosphors. The monodisperse particles of the invention have a rare earth-containing lattice which in one embodiment may be an yttrium-containing lattice or in another may be a lanthanide-containing lattice. The monodisperse particles may have different optical properties based on their composition, their size, and/or their morphology (or shape). Also disclosed is a combination of at least two types of monodisperse particles, where each type is a plurality of monodisperse particles having a single pure crystalline phase of a rare earth-containing lattice, a uniform three-dimensional size, and a uniform polyhedral morphology; and where the types of monodisperse particles differ from one another by composition, by size, or by morphology. In a preferred embodiment, the types of monodisperse particles have the same composition but different morphologies. Methods of making and methods of using the monodisperse particles are disclosed.

  6. Morphologically and size uniform monodisperse particles and their shape-directed self-assembly

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Joshua E.; Bell, Howard Y.; Ye, Xingchen; Murray, Christopher Bruce

    2017-09-12

    Monodisperse particles having: a single pure crystalline phase of a rare earth-containing lattice, a uniform three-dimensional size, and a uniform polyhedral morphology are disclosed. Due to their uniform size and shape, the monodisperse particles self assemble into superlattices. The particles may be luminescent particles such as down-converting phosphor particles and up-converting phosphors. The monodisperse particles of the invention have a rare earth-containing lattice which in one embodiment may be an yttrium-containing lattice or in another may be a lanthanide-containing lattice. The monodisperse particles may have different optical properties based on their composition, their size, and/or their morphology (or shape). Also disclosed is a combination of at least two types of monodisperse particles, where each type is a plurality of monodisperse particles having a single pure crystalline phase of a rare earth-containing lattice, a uniform three-dimensional size, and a uniform polyhedral morphology; and where the types of monodisperse particles differ from one another by composition, by size, or by morphology. In a preferred embodiment, the types of monodisperse particles have the same composition but different morphologies. Methods of making and methods of using the monodisperse particles are disclosed.

  7. Nonlinear branch-point dynamics of multiarm polystyrene

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.; Denberg, Martin

    2006-01-01

    Two branched polystyrene melts with narrow molar mass distribution have been synthesized: a multiarm An-C-C-An pom-pom polystyrene and an An-C asymmetric star polystyrene where n is the number of arms. The pom-pom and the asymmetric star have molar masses of Mw ) 300 kg/mol and Mw ) 275 kg...... polystyrene, the measured transient elongational viscosity is not consistent with a rheological constitutive equation that is separable in time and strain. Contrary to this situation, however, for pom-pom polystyrene, the transient elongational viscosity may be described by a time-strain separable...

  8. Synthesis of high saturation magnetization superparamagnetic Fe3O4 hollow microspheres for swift chromium removal.

    Science.gov (United States)

    Liu, Yubiao; Wang, Yongqiang; Zhou, Shaomin; Lou, Shiyun; Yuan, Lin; Gao, Tao; Wu, Xiaoping; Shi, Xiaojing; Wang, Ke

    2012-09-26

    High saturation magnetization monodisperse Fe(3)O(4) hollow microspheres (109.48 emu/g) with superparamagnetic property at room temperature are promptly synthesized by a one-step solvothermal process with the presence of sodium dodecylbenzenesulfonate as an additive. The as-synthesized products possess superparamagnetism, large cavity, high water solubility, and saturation magnetization at room temperature. In particular, these hollow microspheres exhibit both of a rather short separation time from industry wastewater and a high adsorption capacity about 180 mg/g at high Cr(VI) concentrations, which is much better than those of reported magnetite solid nanoparticles. In addition, the X-ray photoelectron spectra (XPS) show that the uptake of Cr(VI) into the spheres was mainly governed by a physicochemical process. The micelle-assisted Ostwald ripening process was proposed to explain the rapid formation of hollow structures by a series of control experiments. The as-manufactured products with the two advantages mentioned above serve as ideal candidates for environmental remediation materials.

  9. Template-etching route to construct uniform rattle-type Fe3O4@SiO2 hollow microspheres as drug carrier.

    Science.gov (United States)

    Cheng, Lin; Liu, Yuanyuan; Zou, Bingfang; Yu, Yong; Ruan, Weimin; Wang, Yongqiang

    2017-06-01

    Template-etching strategy was put forward to synthesize rattle-type magnetic silica (Fe3O4@SiO2) hollow microspheres in a controlled way. During the experiment, monodisperse Fe2O3 microspheres were fabricated as physical template to generate uniform Fe2O3@SiO2 with controlled shell thicknesses through sol-gel method, and the subsequent Fe2O3 template etching process created variable space between Fe2O3 core and SiO2 shell, and the final calcination process transformed rattle-type Fe2O3@SiO2 hollow microspheres into corresponding Fe3O4@SiO2 product in hydrogen/nitrogen atmosphere. Compared with traditional physical template, here template-etching synthesis of rattle-type hollow microspheres saved the insertion of middle shells and their removal, which simplified the synthesis process with controllable core size and shell thickness. The rattle-type Fe3O4@SiO2 hollow microspheres as drug carrier show efficient doxorubicin (DOX) loading, and the release rate of DOX loaded the rattle-type Fe3O4@SiO2 hollow microspheres exhibit a surprising shell-thickness-dependent and a pH responsive drug release features. Additionally, MTT assays in HeLa cells demonstrated that the Fe3O4@SiO2 nanocarriers were non-toxic even at the concentration of 250µgmL(-1) for 48h. Thus, our results revealed that the Fe3O4@SiO2-DOX could play an important role in the development of intracellular delivery nanodevices for cancer therapy. Copyright © 2017. Published by Elsevier B.V.

  10. In vivo imaging of the morphology and changes in pH along the gastrointestinal tract of Japanese medaka by photonic band-gap hydrogel microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Du, Xuemin [Advanced Laboratory for Environmental Research and Technology, USTC-CityU, Suzhou 215123 (China); Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Centre for Functional Photonics, Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Lei, Ngai-Yu; Hu, Peng [Centre for Functional Photonics, Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Lei, Zhang; Ong, Daniel Hock-Chun [Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong (China); Ge, Xuewu [Advanced Laboratory for Environmental Research and Technology, USTC-CityU, Suzhou 215123 (China); Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Zhicheng, E-mail: zczhang@ustc.edu.cn [Advanced Laboratory for Environmental Research and Technology, USTC-CityU, Suzhou 215123 (China); Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Lam, Michael Hon-Wah, E-mail: bhmhwlam@cityu.edu.hk [Advanced Laboratory for Environmental Research and Technology, USTC-CityU, Suzhou 215123 (China); Centre for Functional Photonics, Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2013-07-17

    Graphical abstract: -- Highlights: •Fabrication of pH-responsive photonic colloidal crystalline microspheres. •Specific photonic band-gap responses occurred in the pH range of 4–5. •Remarkably low in vivo toxicity to Japanese medaka (Oryzia latipes). •In vivo imaging of the morphology and pH along GI tract of Japanese medaka. •Demonstrates bio-imaging potentials of stimuli-responsive photonic materials. -- Abstract: Colloidal crystalline microspheres with photonic band-gap properties responsive to media pH have been developed for in vivo imaging purposes. These colloidal crystalline microspheres were constructed from monodispersed core–shell nano-size particles with poly(styrene-co-acrylic acid) (PS-co-PAA) cores and poly(acrylic acid-co-N-isopropylacrylamide) (PAA-co-PNIPAM) hydrogel shells cross-linked by N,N′-methylenebisacrylamide. A significant shift in the photonic band-gap properties of these colloidal crystalline microspheres was observed in the pH range of 4–5. This was caused by the discontinuous volume phase transition of the hydrogel coating, due to the protonation/deprotonation of its acrylic acid moieties, on the core–shell nano-sized particles within the microspheres. The in vivo imaging capability of these pH-responsive photonic microspheres was demonstrated on a test organism – Japanese medaka, Oryzia latipes – in which the morphology and change in pH along their gastrointestinal (GI) tracts were revealed under an ordinary optical microscope. This work illustrates the potential of stimuli-responsive photonic band-gap materials in tissue-/organ-level in vivo bio-imaging.

  11. Frequency domain photon migration measurements of dense monodisperse charged lattices and analysis using solutions of Ornstein Zernike equations.

    Science.gov (United States)

    Dali, Sarabjyot S; Sevick-Muraca, Eva M

    2012-11-15

    Isotropic scattering coefficient measurements were made of monodisperse polystyrene lattices of two different diameters of 144 nm and 223 nm and at volume fractions ranging from 0.15 to 0.22, using frequency domain photon migration measurements at wavelengths of 660, 685, 785 and 828 nm. The isotropic scattering coefficient measurements were shown to be sensitive to the changing ionic strength (0.5-4 mM, NaCl equiv.) of the dispersions exhibiting hindered scattering owing to structure at the lowest ionic strength values. Monte Carlo simulations and numerical solution of the Ornstein Zernike equations were used to compute isotropic scattering coefficients for comparison to measured values. The interaction potential was modeled as a hard sphere Yukawa potential and the Hypernetted Chain closure was used to solve the OZ equation. Effective particle charges were found after renormalization of the bare particle charge and used to predict the isotropic scattering coefficient. The model data were found to follow similar trends as experimental measurements. The refractive index of the particles has found to be an important factor for predicting experimental isotropic scattering coefficient values. Published by Elsevier Inc.

  12. A Facile Solvothermal Synthesis of Monodisperse Ni Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    YU Peng-fei; CUI Bin; ZHANG Yan; SHI Qi-zhen

    2008-01-01

    A simple solvothermal approach was developed to synthesize uniform spherical monodisperse Ni nanoparticles, which can easily disperse in nonpolar solvents to form homogenous colloidal solution. The as-prepared sample was characterized by XRD, TEM, and FTIR. The results indicate that Ni nanoparticles have the structure of face-centered cube and a narrow distribution with a diameter of (3.5±0.5) nm. The FTIR spectrum reveals that the as a surfactant. The probable formation mechanism of the spherical nanoparticles was also discussed.

  13. Structural disorder versus spin canting in monodisperse maghemite nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Kubickova, S.; Vejpravova, J., E-mail: vejpravo@fzu.cz [Department of Magnetic Nanosystems, Institute of Physics of the ASCR, v.v.i., Na Slovance 2, 182 21 Prague (Czech Republic); Niznansky, D. [Faculty of Science, Department of Inorganic Chemistry, Charles University in Prague, Albertov 2030, 128 40 Prague (Czech Republic); Morales Herrero, M. P. [Instituto de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Ins de la Cruz 3, Campus de Cantoblanco, 28049 Madrid (Spain); Salas, G. [Instituto de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Ins de la Cruz 3, Campus de Cantoblanco, 28049 Madrid (Spain); Instituto Madrileno de Estudios Avanzados en Nanociencia, Campus Universitario de Cantoblanco, 28049 Madrid (Spain)

    2014-06-02

    Monodisperse maghemite nanoparticles with diameter ranging from 7 to 20 nm were examined by the In-field Mössbauer Spectroscopy (IFMS) in varying external magnetic field up to 6 T. Surprisingly, the small-sized particles (7 nm) exhibit nearly no spin canting in contrast to the larger particles with lower surface-to-volume ratio. We demonstrate that the observed phenomenon is originated by lower relative crystallinity of the larger particles with different internal structure. Hence, the persistence of the 2nd and 5th absorption lines in the IFMS cannot be unambiguously assigned to the surface spins.

  14. Monodisperse Silver Nanoparticles Synthesized by a Microwave-Assisted Method

    Institute of Scientific and Technical Information of China (English)

    ZHU Shao-Peng; TANG Shao-Chun; MENG Xiang-Kang

    2009-01-01

    Silver nanoparticles with an average size of about 2Onto are synthesized in a colloidal solution with the aid of microwave irradiation. Neither additional reductant nor stabilizer is required in this microwave-assisted method.The color of the colloidal solution is found to be dark green, different from the characteristic yellow of silver colloidal solutions. The silver nanoparticles in the colloidal solution have a narrow size distribution and large yield quantity. UV-visible absorption spectroscopy analysis reveals that the as-synthesized monodisperse silver nanoparticles have exceptional optical properties. Raman spectroscopy measurements demonstrate that these silver nanoparticles exhibit a notable surface-enhanced Raman scattering ability.

  15. MONODISPERSE MICRON-SIZED POLYACRYLAMIDE PARTICLES SYNTHESIZED BY DISPERSION POLYMERIZATION

    Institute of Scientific and Technical Information of China (English)

    Xin Hou; Bo Gao; Zhe-guo Zhang; Kang-de Yao

    2007-01-01

    Monodisperse micron-sized polyacrylamide (PAM) particles with a regular shape have been successfully prepared through dispersion polymerization of the monomer using a rotary reactor. FTIR and NMR spectroscopic results demonstrated the formation of PAM. POM and TEM observations revealed that PAM particles had a regular shape and good dispersity. A thick layer of surfactant (PVP) still existed on PAM particles after multiple centrifugation and ultrasonic re-dispersion in ethanol, which indicates a strong interaction between PVP and PAM. The effects of various polymerization factors on the average size of PAM particles have also been studied.

  16. Preparation of polyvinylpyrrodione microspheres by dispersion polymerization

    Institute of Scientific and Technical Information of China (English)

    Linfeng ZHAI; Tiejun SHI; Hualin WANG

    2009-01-01

    The preparation of polyvinylpyrrolidone (PVP) microspheres in ethyl acetate by dispersion polymerization with N-vinylpyrrolidone (NVP) as initial monomer, poly(N-vinylpyrrolidone-co-vinyl acetate) (P (NVP-co-VAc)) as dispersant, and 2, 2'-azobisisobutyr-onitrile(AIBN) as initiator is reported. The influences of monomer concentration, dispersant concentration and initiator concentration on the size of PVP microspheres as well as the monomer conversion were studied. The structure and properties of PVP microspheres were analyzed. The results show that the prepared PVP micro-spheres have a mean diameter of 3-4 μm. With an increase in NVP concentration, the size and the molecular weight of the PVP microspheres as well as the monomer conversion all increase. With increasing P(NVP-co-VAc) concentra-tions, the PVP molecular weight and monomer conversion both increase while the size of the microspheres becomes smaller. As the concentration of AIBN increases, the microsphere size and monomer conversion increase whereas the PVP molecular weight decreases. The PVP prepared by dispersion polymerization has a crystal structure, and its molecular weight is lower compared to that prepared by solution polymerization.

  17. The preparation of composite microsphere with hollow core/porous shell structure by self-assembling of latex particles at emulsion droplet interface.

    Science.gov (United States)

    He, Xiao Dong; Ge, Xue Wu; Wang, Mo Zhen; Zhang, Zhi Cheng

    2006-07-15

    A submicrometer-scaled polystyrene/melamine-formaldehyde hollow microsphere composite was prepared by self-assembling of sulfonated polystyrene (SPS) latex particles at the interface of emulsion droplets and then being fixed in place using a hard melamine-formaldehyde (MF) composite layer. For control-released purposes, the influential factors that control the size and uniformity of the packed-droplets and the permeability of the composite shell, including the initial particle location, the hydrophilicity and the size of colloidal templates, the oil phase solvent and reserving time of emulsions after the addition of MF prepolymer, were further studied. Relatively uniform sized particle packed-droplets with an average diameter of 10 microm were obtained. The assembled SPS particles kept ordering and minimal conglutination after the preparation of composite microspheres, which allows of controlling the permeability from the interstices between the particles. Porous-mesh-structured MF composite layer was formed to further control the permeability. The morphology of emulsions and composite microspheres were characterized by optical microscopy, scanning and transmission electron microscopy.

  18. Characterization of a Polyamine Microsphere and Its Adsorption for Protein

    Directory of Open Access Journals (Sweden)

    Huixian Wei

    2012-12-01

    Full Text Available A novel polyamine microsphere, prepared from the water-in-oil emulsion of polyethylenimine, was characterized. The investigation of scanning electron microscopy showed that the polyamine microsphere is a regular ball with a smooth surface. The diameter distribution of the microsphere is 0.37–4.29 μm. The isoelectric point of the microsphere is 10.6. The microsphere can adsorb proteins through the co-effect of electrostatic and hydrophobic interactions. Among the proteins tested, the highest value of adsorption of microsphere, 127.8 mg·g−1 microsphere, was obtained with lipase. In comparison with other proteins, the hydrophobic force is more important in promoting the adsorption of lipase. The microsphere can preferentially adsorb lipase from an even mixture of proteins. The optimum temperature and pH for the selective adsorption of lipase by the microsphere was 35 °C and pH 7.0.

  19. Spectrometric characteristics of polystyrene scintillation films

    CERN Document Server

    Astvatsaturov, A R; Gavalyan, V B; Gavalyan, V G

    1999-01-01

    The spectrometric characteristics of five types of polystyrene scintillation films with thicknesses of 10, 30, 50 and 80 mu m and of analogous 250 mu m thick plates irradiated with sup 2 sup 3 sup 9 Pu, sup 2 sup 3 sup 8 Pu and sup 2 sup 2 sup 6 Ra sources of alpha-particles have been studied. The prospects of utilization of scintillation films as radiators for detection of heavy charged particles and measurement of their energy was experimentally shown.

  20. EXTRUDED POLYSTYRENE FOAM IN FLAT ROOFS

    Directory of Open Access Journals (Sweden)

    Zhukov Aleksey Dmitrievich

    2014-09-01

    Full Text Available In our article we prove the necessity of applying thermal insulation with low water absorption and resistance and preserving mechanical and thermophysical properties in corrosive environment in flat roofs, where there is always a danger of penetrating condensed moisture into the structure. As such material we offered extruded polystyrene foam - heat-insulating polymer material with uniformly distributed closed cells. The products are used in the form of slab insulation and special items - for forming slopes and venting.

  1. Interaction of apo cytochrome c with sulfonated polystyrene nanoparticles.

    Science.gov (United States)

    Liang, Li; Yao, Ping; Gong, Jie; Jiang, Ming

    2004-04-13

    Stable nanoparticle dispersion in aqueous solutions was obtained with partially sulfonated polystyrene. The hydrophobic association of the backbone chains and phenyl groups is balanced by the electrostatic repulsion of the sulfonate groups on the particle surface. The size distribution of the sulfonated polystyrene particles in relation to concentration, degree of sulfonation and chain length, and pH was characterized by dynamic laser light-scattering. The structure and morphology of the particles were characterized with fluorescence and atom force microscopy. Highly sulfonated polystyrene particles can form large complex particles with positively charged protein, apo cytochrome c. Dynamic laser light-scattering and atom force microscopy studies show that the size and distribution of the complex particles depend on the relative amount of apo cytochrome c and sulfonated polystyrene. When sulfonated polystyrene is in excess, apo cytochrome c interacts with sulfonated polystyrene particles forming stable complexes and excessive sulfonated polystyrene particles bind to the periphery of the complexes preventing them from further aggregation. When apo cytochrome c is in excess, apo cytochrome c links the complexes forming much larger particles. Fluorescence study demonstrates that the hydrophobicity/hydrophility of the complex particles is relative to the ratio of apo cytochrome c and sulfonated polystyrene, degree of sulfonation, and pH. Apo cytochrome c not only can neutralize the negative charges on the surface of sulfonated polystyrene particles, but may also insert into the cores disrupting the original structure of sulfonated polystyrene particles.

  2. Monodisperse Femto- to Atto-liter Droplet Formation Using a Nano-Microchannel Interface

    NARCIS (Netherlands)

    Shui, Lingling; Berg, van den Albert; Eijkel, Jan C.T.; Kim, Tae Song; Lee, Yoon-Sik; Chung, Taek-Dong; Jeon, Noo Li; Suh, Kahp-Yang; Choo, Jaebum; Kim, Yong-Kweon

    2009-01-01

    We demonstrate the production of sub-micrometer diameter monodisperse droplets by using a nano-micro channel interface. A perfectly steady nanoscopic liquid filament can be formed by a geometric confinement which eventually gives rise to a stable production of nearly perfectly monodisperse droplets.

  3. Surface properties of poly(ethylene oxide)-based segmented block copolymers with monodisperse hard segments

    NARCIS (Netherlands)

    Husken, D.; Feijen, Jan; Gaymans, R.J.

    2009-01-01

    The surface properties of segmented block copolymers based on poly(ethylene oxide) (PEO) segments and monodisperse crystallizable tetra-amide segments were studied. The monodisperse crystallizable segments (T6T6T) were based on terephthalate (T) and hexamethylenediamine (6). Due to the crystallinity

  4. 无皂乳液聚合法制备PS/TiO2核-壳复合微球%Preparation of PS/TiO2 core-shell composite microspheres by soap-free emulsion polymerization

    Institute of Scientific and Technical Information of China (English)

    李海东; 高文杰; 程凤梅; 白福臣

    2012-01-01

    A series of polystyrene microspheres was prepared via soap-free emulsion polymerization. Polystyrene microspheres was sulphonated, absorbed water and then the reaction was happened between sulfonated polysty- rene and TiO2 in ethanol with TBOT as a reaction precursor, the surface of sulphonated polystyrene micro- spheres was covered by TiO2 and organic-inorganic compound microspheres was acquired. Tangible functional group was grafted on compound microspheres surface, and core-shell -shell heterozygosity microspheres was ob- tained by grafting methyl methacrylate (MMA) on heterozygosity microspheres surface with soap-free emulsion polymerization. The organic-inorganic compound microspheres were characterized by means of Fourier trans- form infrared spectrometer, scanning electron microscope and thermal gravimetric analysis etc. The results show that PS,PS/TiO2 and PS/TiO2/PMMA microspheres surface smooth, spherical degree good and single good dispersancy;controllable shell thickness by change of the quantity of TBOT to PS/TiO2 composite micro- spheres.%采用无皂乳液聚合法制备聚苯乙烯(PS)微球,将所制备的PS微球经磺化吸水后,利用钛酸丁酯作前驱体在乙醇中反应,使TiO2包覆在磺化苯乙烯微球表面,得到有机-无机Ps/TiO2复合微球。在所得的杂化微球表面接枝上可聚官能团,利用无皂乳液聚合将聚甲基丙烯酸甲酯聚合到微球表面,得到核-壳-壳杂化微球。用FT—IR、SEM和TGA等方法对所制得的复合微球进行表征。结果表明PS、PS/TiO2及PS/TiO2/PMMA微球表面光滑,球形度好,单分散性良好;通过改变TBOT的加入量可以控制TiO。对PS微球的包覆厚度。

  5. Designing Zirconium Coated Polystyrene Colloids and Application

    Directory of Open Access Journals (Sweden)

    Diana Chira

    2009-01-01

    Full Text Available A simple technique has been developed to prepare core colloids that are modified using zirconium oxychloride, based on heating a solution of core colloid composites, consisting of poly (ethylenimine (PEI and zirconium oxychloride. The interaction of zirconium oxychloride with the polystyrene (PS core colloids has been investigated using Fourier transform-infrared spectroscopy (FT-IR, energy dispersive X-ray spectroscopy (EDX, and scanning electron microscopy (SEM data. FT-IR studies confirm the occurrence of amine groups present in PEI which are oxidized to carboxyl groups after the reaction. The EDX data and the SEM images confirm the presence of zirconium particles immobilized on the polystyrene surfaces. Demeton, a highly toxic nerve agent, was used due to its ability to easily bind through its organophosphate group illustrating a practical application of the PS-PEI-Zr particles. Attenuated Total Reflection (ATR Spectroscopy was used to assess the interactions between the toxic nerve agent demeton-S and the PS-PEI-Zr particles. The results show that the presented technique for coating polystyrene core colloids with zirconium was successfully accomplished, and the newly formed particles easily bond with demeton agents through the P=O functional group.

  6. Highly reusability surface loaded metal particles magnetic catalyst microspheres (MCM-MPs) for treatment of dye-contaminated water

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ying; Zhang, Kun, E-mail: kun4219@njtech.edu.cn; Yin, Xiaoshuang; Yang, Wenzhong; Zhu, Hongjun

    2016-04-01

    The metal-deposited magnetic catalyst microspheres (MCM-MPs) were successfully synthesized by one facile, high yield and controllable approach. Here, the bare magnetic microspheres were firstly synthesized according to the solvothermal method. Then silica shell were coated on the surface of the magnetic microspheres via sol–gel method, and subsequently with surface modifying with amino in the purpose to form SiO{sub 2}–NH{sub 2} shell. Thus, metal particles were easily adsorbed into the SiO{sub 2}–NH{sub 2} shell and in-situ reduced by NaBH{sub 4} solution. All the obtained products (MCM-Cu, MCM-Ag, MCM-Pd) which were monodisperse and constitutionally stable were exhibited high magnetization and excellent catalytic activity towards dyes solution reduction. The catalytic rate ratio of MCM-Pd: MCM-Cu: MCM-Ag could be 10:3:1. Besides, some special coordination compound Cu{sub 2}(OH){sub 3}Br had been generated in the in-situ reduced process of MCM-Cu, which produced superior cyclical stability (>20 times) than that of MCM-Ag and MCM-Pd. In all, those highly reusability and great catalytic efficiency of MCM-MPs show promising and great potential for treatment of dye-contaminated water. - Graphical abstract: Surface loaded metal particles magnetic catalyst microspheres MCM-MPs for rapid decolorizing dye-contaminated water: Synthesis, characterization and possible mechanisms. - Highlights: • A simple and high yield synthetic method for fabricate multi MCM-MPs is proposed with adequately optimize. • The highest reusability of MCM-Cu is attribute to the coordination compounds Cu{sub 2}(OH){sub 3}Br. • MCM-MPs show excellent catalytic properties under different situations for various dyes • The catalytic mechanism of MCM-MPs is presented.

  7. Organic aerogel microspheres and fabrication method therefor

    Science.gov (United States)

    Mayer, Steven T.; Kong, Fung-Ming; Pekala, Richard W.; Kaschmitter, James L.

    1996-01-01

    Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  8. Self-assembled periodic patterns on the optical fiber tip by microsphere arrays

    Science.gov (United States)

    Pisco, Marco; Galeotti, Francesco; Grisci, Giorgio; Quero, Giuseppe; Cusano, Andrea

    2015-09-01

    In this work, we report a fabrication route for self-assembling periodic patterns on optical fiber tips. The technique is based on self-assembling polystyrene microspheres at the air/water interface and on successive transferring of the monolayer colloidal crystal on the fiber tip. By applying to the fiber further treatments like particle size reduction, metal coating and sphere removal, different periodic structures are conveniently realized. The results obtained indicate that self-assembly technique affords opportunity to create on the optical fiber tip dielectric and metallic-dielectric spheres' arrays with a feature size down to a submicron scale or metallic patterns with a few hundred nanometers at low fabrication costs.

  9. Hydrogen transport and storage in engineered microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Rambach, G. [Lawrence Livermore National Lab., CA (United States); Hendricks, C. [W.J. Schafer Associates, Livermore, CA (United States)

    1996-10-01

    This project is a collaboration between Lawrence Livermore National Laboratory (LLNL) and W.J. Schafer Associates (WJSA). The authors plan to experimentally verify the performance characteristics of engineered glass microspheres that are relevant to the storage and transport of hydrogen for energy applications. They will identify the specific advantages of hydrogen transport by microspheres, analyze the infrastructure implications and requirements, and experimentally measure their performance characteristics in realistic, bulk storage situations.

  10. A one-step method to coat polystyrene particles with an organo-silica shell and their functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Tian-Song, E-mail: dengts@pku.edu.cn [Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany); Bongard, Hans-Josef [Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany); Marlow, Frank, E-mail: marlow@mpi-muelheim.mpg.de [Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany); Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47057 Duisburg (Germany)

    2015-07-15

    A facile method of coating polystyrene (PS) particles with organo-silica and their functionalization was presented. By adding the organo-silane precursor into PS aqueous solution in presence of ammonia, an organo-silica shell could be coated on PS particles directly. This method has several characteristics. First, only one process, one precursor and one solvent were used. Second, the organic groups could be varied from methyl, propyl, vinyl, to mercaptopropyl. The third is the tunable shell thickness with a high monodispersity. The organo-silica shells are further functionalized. The PS@vinyl-SiO{sub 2} particles were used to assemble colloidal crystals, and further modified with bromine, resulting in tunable photonic band gaps. PS@mercaptopropyl-SiO{sub 2} particles allow the encapsulation of Au nanoparticles. The resulting 2.2 nm Au particles were stable at 550 °C and well-distributed in the whole SiO{sub 2} shell with a loading up to 20 wt%. - Graphical abstract: Display Omitted - Highlights: • Demonstrated a one-step controllable coating method of organo-SiO{sub 2} on polystyrene. • The Br-modified PS@vinyl-SiO{sub 2} colloidal crystal has tunable photonic band gaps. • PS@mercaptopropyl-SiO{sub 2} particles allow the encapsulation of small Au nanoparticles.

  11. Extensional Flow of a Polystyrene Boger Fluid Through a 4:1:4 Axisymmetric Contraction/Expansion

    Science.gov (United States)

    Rothstein, Jonathan P.; McKinley, Gareth H.

    1999-01-01

    The creeping flow of a dilute (0.025 wt%) monodisperse polystyrene/polystyrene Boger fluid through a 4:1:4 axisymmetric contraction/expansion is experimentally observed for a wide range of Deborah numbers. Pressure drop measurements across the orifice plate show a large extra pressure drop that increases monotonically with Deborah number above the value observed for a similar Newtonian fluid at the same flow rate. This enhancement in the dimensionless pressure drop is not associated with the onset of a flow instability, yet it is not predicted by existing steady-state or transient numerical computations with simple dumbbell models. It is conjectured that this extra pressure drop is the result of an additional dissipative contribution to the polymeric stress arising from a stress-conformation hysteresis in the strong non-homogeneous extensional flow near the contraction plane. Such a hysteresis has been independently measured and computed in recent studies of homogeneous transient uniaxial stretching of PS/PS Boger fluids. Flow visualization and velocity field measurements using digital particle image velocimetry (DPIV) show large upstream growth of the corner vortex with increasing Deborah number. At large Deborah numbers, the onset of an elastic instability is observed, first locally as small amplitude fluctuations in the pressure measurements, and then globally as an azimuthal precessing of the upstream corner vortex accompanied by periodic oscillations in the pressure drop across the orifice.

  12. Incorporation of pyrene in polypyrrole/polystyrene magnetic beads.

    Science.gov (United States)

    Głowala, Paulina; Budniak, Adam; Krug, Pamela; Wysocka, Barbara; Berbeć, Sylwia; Dec, Robert; Dołęga, Izabela; Kacprzak, Kamil; Wojciechowski, Jarosław; Kawałko, Jakub; Kępka, Paweł; Kępińska, Daria; Kijewska, Krystyna; Mazur, Maciej

    2014-10-15

    Pyrene, a fluorescent dye, was incorporated into polystyrene particles coated with polypyrrole. The incorporation was achieved by treating the polypyrrole/polystyrene (PPy/PS) beads in a tetrahydrofuran (THF) solution of the pyrene fluorophore followed by rinsing with methanol. The polystyrene cores of the beads swell in THF, allowing penetration of pyrene molecules into the polystyrene structure. The addition of methanol causes contraction of the swollen polystyrene, which encapsulates the dye molecules inside the beads. It is shown that the polypyrrole coating is permeable with respect to both the dye and the solvent, allowing the transport of molecules between the polystyrene cores and the contacting solution. The polypyrrole adlayer can be used as a matrix for the incorporation of magnetic nanoparticles. Embedded particles provide magnetic functionality to the PPy/PS beads. It is demonstrated that the pyrene-loaded beads can be manipulated with an external magnetic field. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Coacervate microspheres as carriers of recombinant adenoviruses.

    Science.gov (United States)

    Kalyanasundaram, S; Feinstein, S; Nicholson, J P; Leong, K W; Garver, R I

    1999-01-01

    The therapeutic utility of recombinant adenoviruses (rAds) is limited in part by difficulties in directing the viruses to specific sites and by the requirement for bolus administration, both of which limit the efficiency of target tissue infection. As a first step toward overcoming these limitations, rAds were encapsulated in coacervate microspheres comprised of gelatin and alginate followed by stabilization with calcium ions. Ultrastructural evaluation showed that the microspheres formed in this manner were 0.8-10 microM in diameter, with viruses evenly distributed. The microspheres achieved a sustained release of adenovirus with a nominal loss of bioactivity. The pattern of release and the total amount of virus released was modified by changes in microsphere formulation. Administration of the adenovirus-containing microspheres to human tumor nodules engrafted in mice showed that the viral transgene was transferred to the tumor cells. It is concluded that coacervate microspheres can be used to encapsulate bioactive rAd and release it in a time-dependent manner.

  14. Demonstration of Microsphere Insulation in Cryogenic Vessels

    Science.gov (United States)

    Baumgartner, R. G.; Myers, E. A.; Fesmire, J. E.; Morris, D. L.; Sokalski, E. R.

    2006-04-01

    While microspheres have been recognized as a legitimate insulation material for decades, actual use in full-scale cryogenic storage tanks has not been demonstrated until now. The performance and life-cycle-cost advantages previously predicted have now been proven. Most bulk cryogenic storage tanks are insulated with either multilayer insulation (MLI) or perlite. Microsphere insulation, consisting of hollow glass bubbles, combines in a single material the desirable properties that other insulations only have individually. The material has high crush strength, low density, is noncombustible, and performs well in soft vacuum. These properties were proven during recent field testing of two 22,700-L (6,000-gallon) liquid nitrogen tanks, one insulated with microsphere insulation and the other with perlite. Normal evaporation rates (NER) for both tanks were monitored with precision test equipment and insulation levels within the tanks were observed through view ports as an indication of insulation compaction. Specific industrial applications were evaluated based on the test results and beneficial properties of microsphere insulation. Over-the-road trailers previously insulated with perlite will benefit not only from the reduced heat leak, but also the reduced mass of microsphere insulation. Economic assessments for microsphere-insulated cryogenic vessels including life-cycle cost are also presented.

  15. Evaluation of glibenclamide microspheres for sustained release

    Directory of Open Access Journals (Sweden)

    Kambham Venkateswarlu

    2017-04-01

    Full Text Available Context: Sustained release drug delivery systems are more preferred than the conventional drug delivery systems due to its enhanced bioavailability and patient compliance. Earlier studies reported on glibenclamide (GBCM were not clear and hence, the step has been taken to explore the sustained release drug delivery system of GBCM. Aims: To evaluate the sustained release microspheres obtained of GBCM. Methods: Microspheres were prepared by ionic gelation method using the polymers like Eudragit RS 100 and xanthan gum. Polymers can sustain the drug release from microspheres. The prepared microspheres were subjected to micromeritic studies like Carr’s index, Hausner’s ratio and angle of repose. Results: Micromeritic studies confirmed that the microspheres possessing acceptable flow properties. It was observed from the in vitro release studies, formulations F8 and F9 showed sustained drug release for desired time of 12 h and when compared to F9, formulation F8 showed maximum drug release for 12 h. Conclusions: Results confirmed the formulation F8 consist of the polymers such as Eudragit RS 100 about 150 mg and xanthan gum about 100 mg showed desired sustained release of 12 h with 96.07% and kinetic studies confirmed that the release from microspheres followed non-Fickian diffusion mechanism. Due to its sustained release property, it could enhance the bioavailability of drug thereby improves the patient compliance and expect better treatment than conventional dosage forms.

  16. Optomechanical characterization of freestanding stretchable nanosheet based on polystyrene-polybutadiene-polystyrene copolymer

    Science.gov (United States)

    Kumagai, Hayato; Sato, Nobutaka; Takeoka, Shinji; Sawada, Kazuaki; Fujie, Toshinori; Takahashi, Kazuhiro

    2017-01-01

    In this study, we fabricated a stretchable freestanding ultrathin sheet based on a polystyrene-polybutadiene-polystyrene (SBS) copolymer with entropy-driven elasticity and evaluated its optomechanical properties. The freestanding SBS sheet had a thickness of 675 nm and a size of 10.4 × 10.4 mm2 on a through hole of a poly(dimethylsiloxane) (PDMS) sheet. The measurement of the reflection spectra of the optical interference peaks of the stretched sheets revealed that the SBS nanosheet had a Poisson’s ratio of 0.5-0.68 for a 38% elastic strain, which is one order of magnitude greater than that of parylene.

  17. Abnormal Modulation of Dielectric Band Transmittance of Polystyrene Opal

    Institute of Scientific and Technical Information of China (English)

    HU Xiao-Yong; GONG Qi-Huang; CHENG Bing-Ying; ZHANG Dao-Zhong

    2005-01-01

    @@ The abnormal transmittance in the dielectric band edge of a polystyrene opal is observed and analysed. The transmittance is periodically modulated and the period of modulation varies with the wavelength, which destroys the perfect structure of the photonic band gap. The transmittance modulation originates from the propagation of the low order whispering-gallery mode excited in polystyrene spheres. These results indicate that the whisperinggallery mode has a great influence on practical applications of polystyrene opal.

  18. POE/PLGA composite microspheres: formation and in vitro behavior of double walled microspheres.

    Science.gov (United States)

    Yang, Yi-Yan; Shi, Meng; Goh, Suat-Hong; Moochhala, Shabbir M; Ng, Steve; Heller, Jorge

    2003-03-07

    The poly(ortho ester) (POE) and poly(D,L-lactide-co-glycolide) 50:50 (PLGA) composite microspheres were fabricated by a water-in-oil-in-water (w/o/w) double emulsion process. The morphology of the composite microspheres varied depending on POE content. When the POE content was 50, 60 or 70% in weight, the double walled microspheres with a dense core of POE and a porous shell of PLGA were formed. The formation of the double walled POE/PLGA microspheres was analysed. Their in vitro degradation behavior was characterized by scanning electron microscopy, gel permeation chromatography, Fourier-transform infrared microscopy and nuclear magnetic resonance spectroscopy (NMR). It was found that compared to the neat POE or PLGA microspheres, distinct degradation mechanism was achieved in the double walled POE/PLGA microspheres system. The degradation of the POE core was accelerated due to the acidic microenvironment produced by the hydrolysis of the outer PLGA layer. The formation of hollow microspheres became pronounced after the first week in vitro. 1H NMR spectra showed that the POE core was completely degraded after 4 weeks. On the other hand, the outer PLGA layer experienced slightly retarded degradation after the POE core disappeared. PLGA in the double walled microspheres kept more than 32% of its initial molecular weight over a period of 7 weeks.

  19. Spray Drying as a Processing Technique for Syndiotactic Polystyrene to Powder Form for Part Manufacturing Through Selective Laser Sintering

    Science.gov (United States)

    Mys, N.; Verberckmoes, A.; Cardon, L.

    2016-11-01

    Selective laser sintering (SLS) is a rapidly expanding field of the three-dimensional printing concept. One stumbling block in the evolution of the technique is the limited range of materials available for processing with SLS making the application window small. This article aims at identifying syndiotactic polystyrene (sPS) as a promising material. sPS pellets were processed into powder form with a lab-scale spray dryer with vibrating nozzle. This technique is the focus of this scope as it almost eliminates the agglomeration phenomenon often encountered with the use of solution-based processing techniques. Microspheres obtained were characterized in shape and size by scanning electron microscopy and evaluation of the particle size distribution. The effect the processing technique imparts on the intrinsic properties of the material was examined by differential scanning calorimetry analysis.

  20. Spray Drying as a Processing Technique for Syndiotactic Polystyrene to Powder Form for Part Manufacturing Through Selective Laser Sintering

    Science.gov (United States)

    Mys, N.; Verberckmoes, A.; Cardon, L.

    2017-03-01

    Selective laser sintering (SLS) is a rapidly expanding field of the three-dimensional printing concept. One stumbling block in the evolution of the technique is the limited range of materials available for processing with SLS making the application window small. This article aims at identifying syndiotactic polystyrene (sPS) as a promising material. sPS pellets were processed into powder form with a lab-scale spray dryer with vibrating nozzle. This technique is the focus of this scope as it almost eliminates the agglomeration phenomenon often encountered with the use of solution-based processing techniques. Microspheres obtained were characterized in shape and size by scanning electron microscopy and evaluation of the particle size distribution. The effect the processing technique imparts on the intrinsic properties of the material was examined by differential scanning calorimetry analysis.

  1. PLGA/alginate composite microspheres for hydrophilic protein delivery

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Peng [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Chen, X.B. [Department of Mechanical Engineering, University of Saskatchewan, S7N5A9 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Schreyer, David J., E-mail: david.schreyer@usask.ca [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada)

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. - Highlights: • A double emulsion technique is used to prepare protein-loaded PLGA or PLGA/alginate microspheres. • PLGA, alginate and protein are distributed evenly within microsphere structure. • Addition of alginate improves loading efficiency and slows degradation and protein release. • PLGA/alginate microspheres have favorable biocompatibility.

  2. Selection of quasi-monodisperse super-micron aerosol particles

    Science.gov (United States)

    Rösch, Michael; Pfeifer, Sascha; Wiedensohler, Alfred; Stratmann, Frank

    2014-05-01

    Size-segregated quasi monodisperse particles are essential for e.g. fundamental research concerning cloud microphysical processes. Commonly a DMA (Differential Mobility Analyzer) is used to produce quasi-monodisperse submicron particles. Thereto first, polydisperse aerosol particles are bipolarly charged by a neutralizer, and then selected according to their electrical mobility with the DMA [Knutson et al. 1975]. Selecting a certain electrical mobility with a DMA results in a particle size distribution, which contains singly charged particles as well as undesired multiply charged larger particles. Often these larger particles need to either be removed from the generated aerosol or their signals have to be corrected for in the data inversion and interpretation process. This problem becomes even more serious when considering super-micron particles. Here we will present two different techniques for generating quasi-monodisperse super-micron aerosol particles with no or only an insignificant number of larger sized particles being present. First, we use a combination of a cyclone with adjustable aerodynamic cut-off diameter and our custom-built Maxi-DMA [Raddatz et al. 2013]. The cyclone removes particles larger than the desired ones prior to mobility selection with the DMA. This results in a reduction of the number of multiply charged particles of up to 99.8%. Second, we utilize a new combination of cyclone and PCVI (Pumped Counterflow Virtual Impactor), which is based on purely inertial separation and avoids particle charging. The PCVI instrument was previously described by Boulter et al. (2006) and Kulkarni et al. (2011). With our two setups we are able to produce quasi-monodisperse aerosol particles in the diameter range from 0.5 to 4.4 µm without a significant number of larger undesired particles being present. Acknowledgements: This work was done within the framework of the DFG funded Ice Nucleation research UnIT (INUIT, FOR 1525) under WE 4722/1-1. References

  3. Monodisperse Clusters in Charged Attractive Colloids: Linear Renormalization of Repulsion.

    Science.gov (United States)

    Růžička, Štěpán; Allen, Michael P

    2015-08-11

    Experiments done on polydisperse particles of cadmium selenide have recently shown that the particles form spherical isolated clusters with low polydispersity of cluster size. The computer simulation model of Xia et al. ( Nat. Nanotechnol. 2011 , 6 , 580 ) explaining this behavior used a short-range van der Waals attraction combined with a variable long-range screened electrostatic repulsion, depending linearly on the volume of the clusters. In this work, we term this dependence "linear renormalization" of the repulsive term, and we use advanced Monte Carlo simulations to investigate the kinetically slowed down phase separation in a similar but simpler model. We show that amorphous drops do not dissolve and crystallinity evolves very slowly under linear renormalization, and we confirm that low polydispersity of cluster size can also be achieved using this model. The results indicate that the linear renormalization generally leads to monodisperse clusters.

  4. Solvent: A Key in Digestive Ripening for Monodisperse Au Nanoparticles

    Science.gov (United States)

    Wang, Peng; Qi, Xuan; Zhang, Xuemin; Wang, Tieqiang; Li, Yunong; Zhang, Kai; Zhao, Shuang; Zhou, Jun; Fu, Yu

    2017-01-01

    This work has mainly investigated the influence of the solvent on the nanoparticles distribution in digestive ripening. The experiments suggested that the solvents played a key role in digestive ripening of Au nanoparticles (Au NPs). For the benzol solvents, the resulting size distribution of Au NPs was inversely related to the solvent polarity. It may be interpreted by the low Gibbs free energy of nanoparticles in the high polarity medium, which was supposedly in favor of reducing the nanoparticles distribution. Through digestive ripening in the highly polar benzol solvent of p-chlorotoluene, monodisperse Au NPs with relative standard deviation (RSD) of 4.8% were achieved. This indicated that digestive ripening was an effective and practical way to prepare high-quality nanoparticles, which holds great promise for the nanoscience and nanotechnology.

  5. Structure and Hydration of Highly Branched, Monodisperse Phytoglycogen Nanoparticles

    Science.gov (United States)

    Atkinson, John; Nickels, Jonathan; Stanley, Christopher; Diallo, Souleymane; Katsaras, John; Dutcher, John

    Monodisperse phytoglycogen nanoparticles are a promising, new soft colloidal nanomaterial with many applications in the personal care, food, nutraceutical and pharmaceutical industries. These applications rely on exceptional properties that emerge from the highly branched structure of phytoglycogen and its interaction with water, such as extraordinarily high water retention, and low viscosity and exceptional stability in water. The structure and hydration of the nanoparticles was characterized using small angle neutron scattering (SANS) and quasielastic neutron scattering (QENS). SANS allowed us to determine the size of the nanoparticles, evaluate their radial density profile, quantify the particle-to-particle spacing, and determine their water content. The results show clearly that the nanoparticles are highly hydrated, with each nanoparticle containing 250% of its mass in water, and that aqueous dispersions approach a jamming transition at ~ 25% (w/w). QENS experiments provided an independent and consistent measure of the high level of hydration of the particles.

  6. Synthesis and Characterization of Polystyrene/Nanosilica Organic-Inorganic Hybrid

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A polystyrene(PS)/nanosilica organic-inorganic hybrid material was prepared from styrene monomer and commercial aqueous silica sol containing large amounts of Si-OH by means of emulsion polymerization. The nanosilica sol was modified by the addition of the reactive coupling agent methacryloxy propyltrimethoxysilane(MPS), and the resulting latex particles were protected by surfactants such as sodium dodecyl sulphonate(SDS), hydroxypropyl methyl cellulose(HMPC), and poly(vinylpyrrolidone)(PVP). The effects of the type of surfactant, the amount of surfactant, and the coupling agent on the shape and stability of the resulting latex particles were investigated. The TEM observation indicates that among SDS, HMPC, and PVP, SDS is the best surfactant. When the content of SDS is 0.5% and the amount of MPS is 7% in the system, the latex with obvious core-shell structure could be obtained. The average diameters of the monodispersed particles range from 182 to278 nm, and the average number of silica beads for each composite are 1325 and 4409, respectively. The FTIR analysis shows that PS was chemically linked to silica through MPS. The thermal gravimetric analysis shows that when there is a higher silica content, the hybrid composites have a better heat resistance.

  7. Hierarchical bismuth phosphate microspheres with high photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Lizhai; Wei, Tian; Lin, Nan; Yu, Haiyun [Anhui University of Technology, Ma' anshan (China). Key Laboratory of Materials Science and Processing of Anhui Province

    2016-05-15

    Hierarchical bismuth phosphate microspheres have been prepared by a simple hydrothermal process with polyvinyl pyrrolidone. Scanning electron microscopy observations show that the hierarchical bismuth phosphate microspheres consist of nanosheets with a thickness of about 30 nm. The diameter of the microspheres is about 1 - 3 μm. X-ray diffraction analysis shows that the microspheres are comprised of triclinic Bi{sub 23}P{sub 4}O{sub 44.5} phase. The formation of the hierarchical microspheres depends on polyvinyl pyrrolidone concentration, hydrothermal temperature and reaction time. Gentian violet acts as the pollutant model for investigating the photocatalytic activity of the hierarchical bismuth phosphate microspheres under ultraviolet-visible light irradiation. Irradiation time, dosage of the hierarchical microspheres and initial gentian violet concentration on the photocatalytic efficiency are also discussed. The hierarchical bismuth phosphate microspheres show good photocatalytic performance for gentian violet removal in aqueous solution.

  8. Preparation and photoluminescence enhancement of Li+ and Eu3+ co-doped YPO4 hollow microspheres

    Institute of Scientific and Technical Information of China (English)

    ZHAG Lixin; JIU Hongfang; FU Yuehua; SUN Yixin; WANG Yuanzhong

    2013-01-01

    Li+ and Eu3+ co-doped YPO4 hollow microspheres were successfully synthesized by a sacrificial template method using polystyrene (PS) as template.Techniques of X-ray diffraction (XRD),scanning electron microscopy (SEM),as well as transmission electron microscopy (TEM) were employed to characterize the as-synthesized sample.Furthermore,the photoluminescence (PL)characterization of the Li+ and Eu3+ co-doped YPO4 microsphere was carried out and the effects of the doping concentration of Li+ and Eu3+ active center concentration as well as calcination temperature on the PL properties were studied in detail.The results showed that the incorporation of Li+ ions into the YPO4∶Eu3+ lattice could induce a remarkable improvement of the PL intensity.The highest emission intensity was observed with the compound of 5%Li+ and 5%Eu3+ co-doped YPO4,whose brightness was increased by a factor of more than 2.2 in comparison with that of the YPOa:5%Eu3+.

  9. Epitaxial growth of ZnO nanorod arrays via a self-assembled microspheres lithography

    Science.gov (United States)

    Lin, Bo-Cheng; Ku, Ching-Shun; Lee, Hsin-Yi; Wu, Albert T.

    2017-08-01

    Through a simple hydrothermal method, well-aligned and periodic honeycomb-like ZnO nanorod arrays were fabricated on a c-plane sapphire with an aluminum-doped ZnO (AZO) seed layer. Vertical and highly ordered ZnO nanostructures with the orientation were synthesized by employing a self-assembled monolayer of polystyrene (PS) microspheres as a mask. The optimal growth conditions allowed the growth of only one rod in the confined space between the microspheres. A ϕ-scan exhibited six-fold symmetry, which indicates a favorable epitaxial relationship between the ZnO nanorods, seed layer, and c-plane sapphire substrate. The epitaxial relation is as follows: [0001]ZnO∥[0001]AZO∥[0001]c-planesapphire. These results indicate that the AZO seed layer acts as a buffer layer that can relax the strain between ZnO and c-plane sapphire generated by the large lattice mismatch of 18%. The size of the resulting ZnO nanorods of diameter 20-90 nm could be tuned by varying the concentration of the solution, pH, and duration of reaction. The large aspect ratio of the ZnO nanorod arrays can serve as a template for high-surface-area applications.

  10. Fabrication of nanochannels on polystyrene surface

    Science.gov (United States)

    Li, Dongqing

    2015-01-01

    Solvent-induced nanocrack formation on polystyrene surface is investigated experimentally. Solubility parameter and diffusion coefficient of alcohols are employed to elucidate the swelling and cracking processes as well as the crack size. Experimental results show that the crack size increases with the heating temperature, heating time, and the concentration and volume of the alcohols. A guideline on fabricating single smaller nanocracks on polymers by solvent-induced method is provided. Nanocracks of approximately 64 nm in width and 17.4 nm in depth were created and replicated onto PDMS (polydimethylsiloxane) slabs to form nanochannels. PMID:25945143

  11. Integrated lenses in polystyrene microfluidic devices

    KAUST Repository

    Fan, Yiqiang

    2013-04-01

    This paper reports a new method for integrating microlenses into microfluidic devices for improved observation. Two demonstration microfluidic devices were provided which were fabricated using this new technique. The integrated microlenses were fabricated using a free-surface thermo-compression molding method on a polystyrene (PS) sheet which was then bonded on top of microfluidic channels as a cover plate, with the convex microlenses providing a magnified image of the channel for the easier observation of the flow in the microchannels. This approach for fabricating the integrated microlens in microfluidic devices is rapid, low cost and without the requirement of cleanroom facilities. © 2013 IEEE.

  12. Solid polystyrene and deuterated polystyrene light output response to fast neutrons

    Science.gov (United States)

    Simpson, R.; Danly, C.; Glebov, V. Yu.; Hurlbut, C.; Merrill, F. E.; Volegov, P. L.; Wilde, C.

    2016-04-01

    The Neutron Imaging System has proven to be an important diagnostic in studying DT implosion characteristics at the National Ignition Facility. The current system depends on a polystyrene scintillating fiber array, which detects fusion neutrons born in the DT hotspot as well as neutrons that have scattered to lower energies in the surrounding cold fuel. Increasing neutron yields at NIF, as well as a desire to resolve three-dimensional information about the fuel assembly, have provided the impetus to build and install two additional next-generation neutron imaging systems. We are currently investigating a novel neutron imaging system that will utilize a deuterated polystyrene (CD) fiber array instead of standard hydrogen-based polystyrene (CH). Studies of deuterated xylene or deuterated benzene liquid scintillator show an improvement in imaging resolution by a factor of two [L. Disdier et al., Rev. Sci. Instrum. 75, 2134 (2004)], but also a reduction in light output [V. Bildstein et al., Nucl. Instrum. Methods Phys. Res., Sect. A 729, 188 (2013); M. I. Ojaruega, Ph.D. thesis, University of Michigan, 2009; M. T. Febbraro, Ph.D. thesis, University of Michigan, 2014] as compared to standard plastic. Tests of the relative light output of deuterated polystyrene and standard polystyrene were completed using 14 MeV fusion neutrons generated through implosions of deuterium-tritium filled capsules at the OMEGA laser facility. In addition, we collected data of the relative response of these two scintillators to a wide energy range of neutrons (1-800 MeV) at the Weapons Neutrons Research Facility. Results of these measurements are presented.

  13. Release of macromolecules from albumin-heparin microspheres

    NARCIS (Netherlands)

    Kwon, Glen S.; Bae, You Han; Cremers, Harry; Feijen, Jan; Kim, Sung Wan

    1992-01-01

    Hydrophilic microspheres based on albumin-heparin conjugates have been prepared as a macromolecular delivery system. The soluble albumin-heparin conjugate was synthesized and crosslinked in a water-in-oil emulsion with glutaraldehyde to form microspheres in the same manner as for albumin microsphere

  14. Rheological Behavior of an Epoxy Resin with Hollow Glass Microspheres

    Science.gov (United States)

    Costa, Cleber C.; Calado, Verônica; Tavares, Frederico W.

    2008-07-01

    An investigation was carried out on the rheological behavior of a TET/DGEBA epoxy formulations with hollow glass microspheres using different types and different volume fractions of microspheres to manufacture composites. It was proposed an equation to describe viscosity as a function of microsphere volume fracion. The fit to the experimental data was excellent.

  15. Preparation of microstructured hydroxyapatite microspheres using oil in water emulsions

    Indian Academy of Sciences (India)

    T S Pradeesh; M C Sunny; H K Varma; P Ramesh

    2005-08-01

    Hydroxyapatite (HAP) microspheres with peculiar spheres-in-sphere morphology were prepared by using oil-in-water emulsions and solvent evaporation technique. Ethylene vinyl acetate co-polymer (EVA) was used as the binder material. Preparation of HAP/EVA microspheres was followed by the thermal debinding and sintering at 1150°C for 3 h to obtain HAP microspheres. Each microsphere of 100–1000 m was in turn composed of spherical hydroxyapatite granules of 2–15 m size which were obtained by spray drying the precipitated HAP. The parameters such as percentage of initial HAP loading, type of stabilizer, concentration of stabilizer, stirring speed and temperature of microsphere preparation were varied to study their effect on the particle size and geometry of the microspheres obtained. It was observed that these parameters do have an effect on the size and shape of the microspheres obtained, which in turn will affect the sintered HAP microstructure. Of the three stabilizers used viz. polyoxyethylene(20) sorbitan monopalmitate (Tween-40), sodium laurate and polyvinyl alcohol (PVA), only PVA with a concentration not less than 0.1 wt% showed controlled stabilization of HAP granules resulting in spherical microspheres of required size. Morphologically better spherical microspheres were obtained at 20°C. Increasing the stirring speed produced smaller microspheres. Smaller microspheres having size < 50 m were obtained at a stirring speed of 1500 ± 50 rpm. A gradual decrease in pore size was observed in the sintered microspheres with increase in HAP loading.

  16. Colloidal crystals by electrospraying polystyrene nanofluids

    Science.gov (United States)

    2013-01-01

    This work introduces the electrospray technique as a suitable option to fabricate large-scale colloidal nanostructures, including colloidal crystals, in just a few minutes. It is shown that by changing the deposition conditions, different metamaterials can be fabricated: from scattered monolayers of polystyrene nanospheres to self-assembled three-dimensional ordered nanolayers having colloidal crystal properties. The electrospray technique overcomes the main problems encountered by top-down fabrication approaches, largely simplifying the experimental setup. Polystyrene nanospheres, with 360-nm diameter, were typically electrosprayed using off-the-shelf nanofluids. Several parameters of the setup and deposition conditions were explored, namely the distance between electrodes, nanofluid conductivity, applied voltage, and deposition rate. Layers thicker than 20 μm and area of 1 cm2 were typically produced, showing several domains of tens of microns wide with dislocations in between, but no cracks. The applied voltage was in the range of 10 kV, and the conductivity of the colloidal solution was in the range of 3 to 4 mS. Besides the morphology of the layers, the quality was also assessed by means of optical reflectance measurements showing an 80% reflectivity peak in the vicinity of 950-nm wavelength. PMID:23311494

  17. Filtration application from recycled expanded polystyrene.

    Science.gov (United States)

    Shin, C

    2006-10-01

    Water-in-oil emulsion with drop size less than 100 mum is difficult to separate. Coalescence filtration is economical and effective for separation of secondary dispersions. Coalescence performance depends on flow rate, bed depth, fiber surface properties, and drop size. The amount of surface area of the fibers directly affects the efficiency. A new recycling method was investigated in the previous work in which polystyrene (PS) sub-mum fibers were electro-spun from recycled expanded polystyrene (EPS). These fibers are mixed with micro glass fibers to modify the glass fiber filter media. The filter media are tested in the separation of water droplets from an emulsion of water droplets in oil. The experimental results in this work show that adding nanofibers to conventional micron sized fibrous filter media improves the separation efficiency of the filter media but also increases the pressure drop. An optimum in the performance occurs (significant increase in efficiency with minimal increase in pressure drop) with the addition of about 4% by mass of 500 nm diameter PS nanofibers to glass fibers for the filters.

  18. Computational dynamics of acoustically driven microsphere systems.

    Science.gov (United States)

    Glosser, Connor; Piermarocchi, Carlo; Li, Jie; Dault, Dan; Shanker, B

    2016-01-01

    We propose a computational framework for the self-consistent dynamics of a microsphere system driven by a pulsed acoustic field in an ideal fluid. Our framework combines a molecular dynamics integrator describing the dynamics of the microsphere system with a time-dependent integral equation solver for the acoustic field that makes use of fields represented as surface expansions in spherical harmonic basis functions. The presented approach allows us to describe the interparticle interaction induced by the field as well as the dynamics of trapping in counter-propagating acoustic pulses. The integral equation formulation leads to equations of motion for the microspheres describing the effect of nondissipative drag forces. We show (1) that the field-induced interactions between the microspheres give rise to effective dipolar interactions, with effective dipoles defined by their velocities and (2) that the dominant effect of an ultrasound pulse through a cloud of microspheres gives rise mainly to a translation of the system, though we also observe both expansion and contraction of the cloud determined by the initial system geometry.

  19. RESEARCHES OF WORKING LIFE OF FOAM POLYSTYRENE OF BUILDING APPOINTMENT

    Directory of Open Access Journals (Sweden)

    Guyumdzhjan Perch Pogosovich

    2012-09-01

    Full Text Available Results of experimental researches of physicomechanical properties of foam polystyrene thermal insulation materials are presented in article. The operational resource was defined on materials subject to ageing, action of liquid excited environments and atmospheric impacts. The destructive processes leading to destruction of foam polystyrene are revealed.

  20. Stress relaxation of bi-disperse polystyrene melts

    DEFF Research Database (Denmark)

    Hengeller, Ludovica; Huang, Qian; Dorokhin, Andriy

    2016-01-01

    We present start-up of uniaxial extension followed by stress relaxation experiments of a bi-disperse 50 % by weight blend of 95k and 545k molecular weight polystyrene. We also show, for comparison, stress relaxation measurements of the polystyrene melts with molecular weight 95k and 545k, which a...

  1. Pegylated polystyrene particles as a model system for artificial cells

    NARCIS (Netherlands)

    Meng, Fenghua; Engbers, Gerard H.M.; Gessner, Andrea; Müller, Reiner H.; Feijen, Jan

    2004-01-01

    Pegylated polystyrene particles (PS-PEG) were prepared as a model system for artificial cells, by modification of carboxyl polystyrene particles (PS-COOH) with homo- and hetero-bifunctional polyethylene glycols (PEG, MW 1500, 3400, and 5000) containing an amino end group for immobilization and an am

  2. Dual-Purpose Millikan Experiment with Polystyrene Spheres

    Science.gov (United States)

    Wall, C. N.; Christensen, F. E.

    1975-01-01

    This procedure, using polystyrene spheres of specified diameter, renders the Millikan oil drop experiment more accurate than the conventional procedure of the polystyrene spheres, eliminates size estimation error, and removes the guesswork involved in assigning proper index integers to the observed charges. (MLH)

  3. Nanofiltration membranes of poly(styrene-co-chloro-methylstyrene)-grafted-DGEBA reinforced with gold and polystyrene nanoparticles for water purification

    Science.gov (United States)

    Kausar, Ayesha; Siddiq, Muhammad

    2015-10-01

    The matrix material for nanofiltration membranes was prepared through chemical grafting of poly(styrene-co-chloromethylstyrene) (PSCMS) to DGEBA using hexamethylenediamine as linker. The phase inversion technique was used to form PSCMS-g-DGEBA membranes. This effort also involves the designing of gold nanoparticles and its composite nanoparticles with polystyrene microspheres as matrix reinforcement. The nanoporous morphology was observed at lower filler content and there was formation of nanopattern at increased nanofiller content. The tensile strength was improved from 32.5 to 35.2 MPa with the increase in AuNPs-PSNPs loading from 0.1 to 1 wt%. The glass transition temperature was also enhanced from 132 to 159 °C. The membrane properties were measured via nanofiltration set-up. Higher pure water permeation flux, recovery, and salt rejection were measured for novel membranes. PSCMS-g-DGEBA/AuNPs-PSNPs membrane with 1 wt% loading showed flux of 2.01 mL cm-2 min-1 and salt rejection ratio of 70.4 %. Efficiency of the gold/polystyrene nanoparticles reinforced membranes for the removal of Hg2+ and Pb2 was found to be 99 %. Novel hybrid membranes possess fine characteristics to be utilized in industrial water treatment units.

  4. Spore surface glycoproteins of Colletotrichum lindemuthianum are recognized by a monoclonal antibody which inhibits adhesion to polystyrene.

    Science.gov (United States)

    Hughes, H B; Carzaniga, R; Rawlings, S L; Green, J R; O'Connell, R J

    1999-08-01

    Conidia (spores) of Colletotrichum lindemuthianum, a fungal plant pathogen causing bean anthracnose, adhere to the aerial parts of host plants to initiate the infection process. These spores possess a fibrillar 'spore coat' as well as a cell wall. In a previous study a mAb, UB20, was raised that recognized glycoproteins on the spore surface. In this study UB20 was used to localize and characterize these glycoproteins and to investigate their possible role in adhesion. Glycoproteins recognized by UB20 were concentrated on the outer surface of the spore coat and, to a lesser extent, at the plasma membrane/cell wall interface. Extraction of spores with hot water or 0.2% SDS resulted in removal of the spore coat. Western blotting with UB20 showed that a relatively small number of glycoproteins were extracted by these procedures, including a major component at 110 kDa. Biotinylation of carbohydrate moieties, together with cell fractionation, confirmed that these glycoproteins were exposed at the surface of the spores. In adhesion assays, > 90% of ungerminated conidia attached to polystyrene Petri dishes within 30 min. UB20 IgG at low concentrations inhibited attachment in an antigen-specific manner. This suggests that the glycoproteins recognized by this mAb may function in the initial rapid attachment of conidia to hydrophobic substrata. Polystyrene microspheres bound selectively to the 110 kDa glycoprotein in Western blots, providing further evidence that this component could mediate interactions with hydrophobic substrata.

  5. Interaction between polystyrene spheres by atomic force microscopy

    CERN Document Server

    Looi, L

    2002-01-01

    The interaction between a single polystyrene particle and a polystyrene substrate has been previously reported by a number of investigators. However, the effects of relative humidity, applied load and contact time on the adhesion of polystyrene surfaces have not been investigated and these effects are poorly understood. It is the primary aim of the current work to characterise the effect of the aforementioned parameters on the adhesion of polystyrene surfaces using atomic force microscopy. The polystyrene used in this study contained 1% of di-vinyl benzene as a cross-linking agent. From the work conducted using the custom-built instrument, the dependency of adhesion forces on the relative humidity is greatest at relative humidities above 60% where capillary forces cause a sharp increase in adhesion with increasing relative humidity. Hysteresis was observed in the solid-solid contact gradient of the accompanying force curves, suggesting non-elastic behaviour at the contact area of the surfaces

  6. Numerical test on polystyrene tunnel seismic-isolation material

    Directory of Open Access Journals (Sweden)

    He Jianping

    2016-09-01

    Full Text Available Stress-strain mechanical properties of polystyrene foam plastic material were tested under different loading conditions. An empirical constitutive model for describing metal materials was proposed for the polystyrene plastic foam. The static and dynamic tests results show that the ductility and watertightness of the polystyrene plastic foam are significantly improved. At the same time, in order to check its seismic-isolation property, the high-performance foam concrete as filling materials of Galongla tunnel in Tibet was simulated by FEM. The simulated results show that the polystyrene plastic foam can remarkably decrease the stress and the plastic zone in final lining, so it can effectively reduce the seismic damage of the tunnel. Considering the seismic-isolation property and low price of polystyrene plastic foam, it is a good reference for the anti-seismic design of tunnels in high intensity zones.

  7. Preparation and characterization of magnetic porous carbon microspheres for removal of methylene blue by a heterogeneous Fenton reaction.

    Science.gov (United States)

    Zhou, Lincheng; Shao, Yanming; Liu, Junrui; Ye, Zhengfang; Zhang, He; Ma, Junjun; Jia, Yan; Gao, Weijie; Li, Yanfeng

    2014-05-28

    High-specific-surface-area magnetic porous carbon microspheres (MPCMSs) were fabricated by annealing Fe(2+)-treated porous polystyrene (PS) microspheres, which were prepared using a two-step seed emulsion polymerization process. The resulting porous microspheres were then sulfonated, and Fe(2+) was loaded by ion exchange, followed by annealing at 250 °C for 1 h under an ambient atmosphere to obtain the PS-250 composite. The MPCMS-500 and MPCMS-800 composites were obtained by annealing PS-250 at 500 and 800 °C for 1 h, respectively. The iron oxide in MPCMS-500 mainly existed in the form of Fe3O4, which was concluded by characterization. The MPCMS-500 carbon microspheres were used as catalysts in heterogeneous Fenton reactions to remove methylene blue (MB) from wastewater with the help of H2O2 and NH2OH. The results indicated that this catalytic system has a good performance in terms of removal of MB; it could remove 40 mg L(-1) of MB within 40 min. After the reaction, the catalyst was conveniently separated from the media within several seconds using an external magnetic field, and the catalytic activity was still viable even after 10 removal cycles. The good catalytic performance of the composites could be attributed to synergy between the functions of the porous carbon support and the Fe3O4 nanoparticles embedded in the carrier. This work indicates that porous carbon spheres provide good support for the development of a highly efficient heterogeneous Fenton catalyst useful for environmental pollution cleanup.

  8. Monodispersed Zinc Oxide Nanoparticle-Dye Dyads and Triads

    Energy Technology Data Exchange (ETDEWEB)

    Gladfelter, Wayne L. [Univ. of Minnesota, Minneapolis, MN (United States); Blank, David A. [Univ. of Minnesota, Minneapolis, MN (United States); Mann, Kent R. [Univ. of Minnesota, Minneapolis, MN (United States)

    2017-06-22

    events at a fundamental level. This was combined with the synthesis of a broad range of sensitizers that provide systematic variation of the energetics, excited state dynamics, structure and interfacial bonding. The key is that the monodisperse nature and high dispersibility of the ZnO NCs made these experiments reproducible; in essence, the measurements were on discrete molecular species rather than on the complicated mixtures that resulted from the typical fabrication of functional photovoltaic cells. The monodispersed nature of the NCs also allowed the use of quantum confinement to investigate the role of donor/acceptor energetic alignment in chemically identical systems. The results added significantly to our basic understanding of energy and charge transfer events at molecule-semiconductor interfaces and will help the R&D community realize zinc oxide's full potential in solar cell applications.

  9. Biosensing by WGM Microspherical Resonators

    Directory of Open Access Journals (Sweden)

    Giancarlo C. Righini

    2016-06-01

    Full Text Available Whispering gallery mode (WGM microresonators, thanks to their unique properties, have allowed researchers to achieve important results in both fundamental research and engineering applications. Among the various geometries, microspheres are the simplest 3D WGM resonators; the total optical loss in such resonators can be extremely low, and the resulting extraordinarily high Q values of 108–109 lead to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. They can also be coated in order to better control their properties or to increase their functionality. Their very high sensitivity to changes in the surrounding medium has been exploited for several sensing applications: protein adsorption, trace gas detection, impurity detection in liquids, structural health monitoring of composite materials, detection of electric fields, pressure sensing, and so on. In the present paper, after a general introduction to WGM resonators, attention is focused on spherical microresonators, either in bulk or in bubble format, to their fabrication, characterization and functionalization. The state of the art in the area of biosensing is presented, and the perspectives of further developments are discussed.

  10. Biosensing by WGM Microspherical Resonators

    Science.gov (United States)

    Righini, Giancarlo C.; Soria, Silvia

    2016-01-01

    Whispering gallery mode (WGM) microresonators, thanks to their unique properties, have allowed researchers to achieve important results in both fundamental research and engineering applications. Among the various geometries, microspheres are the simplest 3D WGM resonators; the total optical loss in such resonators can be extremely low, and the resulting extraordinarily high Q values of 108–109 lead to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. They can also be coated in order to better control their properties or to increase their functionality. Their very high sensitivity to changes in the surrounding medium has been exploited for several sensing applications: protein adsorption, trace gas detection, impurity detection in liquids, structural health monitoring of composite materials, detection of electric fields, pressure sensing, and so on. In the present paper, after a general introduction to WGM resonators, attention is focused on spherical microresonators, either in bulk or in bubble format, to their fabrication, characterization and functionalization. The state of the art in the area of biosensing is presented, and the perspectives of further developments are discussed. PMID:27322282

  11. Efficient thermolysis route to monodisperse Cu₂ZnSnS₄ nanocrystals with controlled shape and structure

    National Research Council Canada - National Science Library

    Zhang, Xiaoyan; Guo, Guobiao; Ji, Cheng; Huang, Kai; Zha, Chenyang; Wang, Yifeng; Shen, Liming; Gupta, Arunava; Bao, Ningzhong

    2014-01-01

    Monodisperse Cu2ZnSnS4 (CZTS) nanocrystals with tunable shape, crystalline phase, and composition are synthesized by efficient thermolysis of a single source precursor of mixed metal-oleate complexes in hot organic solvents...

  12. Cr/alpha-Cr2O3 monodispersed spherical core-shell particles based solar absorbers

    CSIR Research Space (South Africa)

    Khamlich, S

    2011-07-01

    Full Text Available Monodispersed spherical core-shell particles of Cr/alpha-Cr2O3 cermet ACG coatings investigated within this contribution could be successfully employed in thermal converters. Their selectivity depends on their chemical, physical and structural...

  13. Improving photoprotection: 4-methylbenzylidene camphor microspheres.

    Science.gov (United States)

    Centini, Marisanna; Miraglia, Giovanna; Quaranta, Valeria; Buonocore, Anna; Anselmi, Cecilia

    2014-05-22

    Abstract We propose a new approach for photoprotection. 4-Methylbenzylidene camphor (4-MBC), one of the most widely used UV filters, was encapsulated in microspheres, with a view to overcoming problems (percutaneous absorption, photodegradation and lack of lasting effect) arising with organic sunscreens, and to achieve safe photoprotection. We focused on this filter in the light of the Cosmetics Europe opinion concerning its possible effects on the thyroid gland. Microspheres were prepared by emulsification-solvent evaporation, using different amounts of 4-MBC and characterized for morphology, encapsulation efficiency and particle size. The particles were then mixed in O/W emulsions. The in vitro sun protection factors, in vitro release and photostability were investigated and compared with emulsions containing the free sunscreen. The new microspheres offer good morphology and loading (up to 40%), and the same photoprotection as the free filter while at the same time protecting it from photodegradation. The systems also give a slower release from the emulsions.

  14. Removal of radioactive contaminants by polymeric microspheres.

    Science.gov (United States)

    Osmanlioglu, Ahmet Erdal

    2016-11-01

    Radionuclide removal from radioactive liquid waste by adsorption on polymeric microspheres is the latest application of polymers in waste management. Polymeric microspheres have significant immobilization capacity for ionic substances. A laboratory study was carried out by using poly(N-isopropylacrylamide) for encapsulation of radionuclide in the liquid radioactive waste. There are numbers of advantages to use an encapsulation technology in radioactive waste management. Results show that polymerization step of radionuclide increases integrity of solidified waste form. Test results showed that adding the appropriate polymer into the liquid waste at an appropriate pH and temperature level, radionuclide was encapsulated into polymer. This technology may provide barriers between hazardous radioactive ions and the environment. By this method, solidification techniques became easier and safer in nuclear waste management. By using polymer microspheres as dust form, contamination risks were decreased in the nuclear industry and radioactive waste operations.

  15. The high surface energy of NiO {110} facets incorporated into TiO2 hollow microspheres by etching Ti plate for enhanced photocatalytic and photoelectrochemical activity

    Science.gov (United States)

    Li, Jian; Cui, Hongzhi; Song, Xiaojie; Wei, Na; Tian, Jian

    2017-02-01

    We present a rational design for the controllable synthesis of NiO/TiO2 hollow microspheres (NTHMs) with Ti plate via a one-pot template-free synthesis strategy. Specifically, to enhance the formation of hollow microspheres, part of the titanium source is provided by the Ti plate. The hollow spherical NiO/TiO2 particles possess unique microstructural characteristics, namely, a higher specific surface area (∼65.82 m2 g-1), a larger mesoporous structure (∼7.79 nm), and hierarchical nanoarchitectures connected with mesopores within the shell (monodispersed size of ∼1 μm and shell thickness of ∼80 nm). In addition, as a cocatalyst for improved catalytic activity, the incorporated NiO nanoparticles with exposed high surface energy {110} facets displayed an outstanding performance. It has been proven that this facile nanostructure possesses remarkably high photoelectrochemical and photocatalytic activities. The main mechanism for enhancement of photocatalytic activity is attributed to the construction of p-n junctions with an inner electric field between TiO2 and NiO, which can dramatically enhance the separation efficiency of the photogenerated electron-hole pairs. This strategy could be applied to fabricate mixed metal oxide hollow microspheres toward the photoelectrochemical catalysis.

  16. Preparation of Monodisperse Nanoparticle of Layered Double Hydroxides and Polyoxyethylene Sulfate

    Institute of Scientific and Technical Information of China (English)

    XU Huizhong; QIN Lianjie; ZHANG Hong; YANG Qinzheng; YANG Jing

    2005-01-01

    In order to obtain the bio-molecule/ LDHs nanocomposites having regular crystal structure,three nanocomposites of layered double hydroxides and polyoxyethylene sulfates were prepared by ion-exchange method. TEM analysis reveals that the monodisperse rigid .sphere of approximately 200 nm in diameter could be gotten when the intergallery anion was PEGS-400. Such monodisperse nanoparticle could be used as a promising precursor for preparing bio-molecule/LDHs nanocomposites.

  17. Multipod-like silica/polystyrene clusters

    Science.gov (United States)

    Désert, Anthony; Morele, Jérémy; Taveau, Jean-Christophe; Lambert, Olivier; Lansalot, Muriel; Bourgeat-Lami, Elodie; Thill, Antoine; Spalla, Olivier; Belloni, Luc; Ravaine, Serge; Duguet, Etienne

    2016-03-01

    Multipod-like clusters composed of a silica core and PS satellites are prepared according to a seeded-growth emulsion polymerization of styrene in the presence of size-monodisperse silica particles previously surface-modified with methacryloxymethyltriethoxysilane. Tuning the diameter and concentration of the silica seeds affords homogeneous batches of tetrapods, hexapods, octopods, nonapods and dodecapods with morphology yields as high as 80%. Three-dimensional reconstructions by cryo-electron tomography are presented on large fields for the first time to show the high symmetry and regularity of the clusters demonstrating the good control of the synthesis process. These synthesis experiments are visited again digitally, in order to successfully refine an original simulation model and better understand the correlation between the history of the cluster growth and the final composition of the cluster mixture. Finally, using the model as a predictive tool and varying the extra experimental conditions, e.g. the composition of the surfactant mixture and the styrene concentration, result in trapping other cluster morphologies, such as tripods.Multipod-like clusters composed of a silica core and PS satellites are prepared according to a seeded-growth emulsion polymerization of styrene in the presence of size-monodisperse silica particles previously surface-modified with methacryloxymethyltriethoxysilane. Tuning the diameter and concentration of the silica seeds affords homogeneous batches of tetrapods, hexapods, octopods, nonapods and dodecapods with morphology yields as high as 80%. Three-dimensional reconstructions by cryo-electron tomography are presented on large fields for the first time to show the high symmetry and regularity of the clusters demonstrating the good control of the synthesis process. These synthesis experiments are visited again digitally, in order to successfully refine an original simulation model and better understand the correlation between the

  18. Quantum Magnetomechanics with Levitating Superconducting Microspheres

    CERN Document Server

    Romero-Isart, O; Navau, C; Sanchez, A; Cirac, J I

    2011-01-01

    We show that by magnetically trapping a superconducting microsphere close to a quantum circuit, it is experimentally feasible to perform ground state cooling and to prepare quantum superpositions of the center-of-mass motion of the microsphere. Due to the absence of clamping losses and time dependent electromagnetic fields, the mechanical motion of micrometer-sized metallic spheres in the Meissner state is predicted to be extremely well isolated from the environment. Hence, we propose to combine the technology of magnetic mictrotraps and superconducting qubits to bring relatively large objects to the quantum regime.

  19. A microsphere suspension model of metamaterial fluids

    Directory of Open Access Journals (Sweden)

    Qian Duan

    2017-05-01

    Full Text Available Drawing an analogy to the liquid phase of natural materials, we theoretically propose a microsphere suspension model to realize a metamaterial fluid with artificial electromagnetic indexes. By immersing high-ε, micrometer-sized dielectric spheres in a low-ε insulating oil, the structured fluid exhibits liquid-like properties from dispersing phase as well as the isotropic negative electromagnetic parameters caused by Mie resonances from dispersed microspheres. The work presented here will benefit the development of structured fluids toward metamaterials.

  20. Periodic jetting and monodisperse jet drops from oblique gas injection

    Science.gov (United States)

    McRae, Oliver; Gaillard, Antoine; Bird, James C.

    2017-07-01

    When air is blown in a straw or tube near an air-liquid interface, typically one of two behaviors is observed: a dimple in the liquid's surface, or a frenzy of sputtering bubbles, waves, and spray. Here we report and characterize an intermediate regime that can develop when a confined air jet enters the interface at an angle. This regime is oscillatory with a distinct characteristic frequency and can develop periodic angled jets that can break up into monodisperse aerosols. The underlying mechanisms responsible for this highly periodic regime are not well understood. Here we flow a continuous stream of gas through a tube near a liquid surface, observing both optically and acoustically the deformation of the liquid-air interface as various parameters are systematically adjusted. We show that the Kelvin-Helmholtz instability is responsible for the inception of waves within a cavity formed by the gas. Inertia, gravity, and capillary forces both shape the cavity and govern the frequency and amplitude of these gas-induced cavity waves. The flapping cavity focuses the waves into a series of periodic jets that can break up into droplets following the Rayleigh-Plateau instability. We present scaling arguments to rationalize the fundamental frequencies driving this system, as well as the conditions that bound the periodic regime. These frequencies and conditions compare well with our experimental results.

  1. Jamming of Monodisperse Cylindrical Grains in Featureless Vertical Channels

    Science.gov (United States)

    Friedl, Nicholas; Baxter, G. William

    2014-03-01

    We study jamming of low aspect-ratio cylindrical Delrin grains falling through a featureless vertical channel under the influence of gravity. These grains have an aspect-ratio less than two (H/D aspirin tablets, 35mm film canisters, poker chips, or coins. Monodisperse grains are allowed to fall under the influence of gravity through a uniform channel of square cross-section where the channel width is greater than the grain size and constant along the length of the channel. No combination of grain heights and diameters is equal to the channel width. Collections of grains sometimes form jams, stable structures in which the grains are supported by the channel walls and not by grains or walls beneath them. The probability of a jam occurring and the jam's strength are influenced by the grain dimensions and channel width. We will present experimental measurements of the jamming probability and jam strength and discuss the relationship of these results to other experiments and theories. Supported by an Undergraduate Research Grant from Penn State Erie, The Behrend College.

  2. Monodisperse Platinum and Rhodium Nanoparticles as Model Heterogeneous Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Grass, Michael Edward [Univ. of California, Berkeley, CA (United States)

    2008-09-01

    Model heterogeneous catalysts have been synthesized and studied to better understand how the surface structure of noble metal nanoparticles affects catalytic performance. In this project, monodisperse rhodium and platinum nanoparticles of controlled size and shape have been synthesized by solution phase polyol reduction, stabilized by polyvinylpyrrolidone (PVP). Model catalysts have been developed using these nanoparticles by two methods: synthesis of mesoporous silica (SBA-15) in the presence of nanoparticles (nanoparticle encapsulation, NE) to form a composite of metal nanoparticles supported on SBA-15 and by deposition of the particles onto a silicon wafer using Langmuir-Blodgett (LB) monolayer deposition. The particle shapes were analyzed by transmission electron microscopy (TEM) and high resolution TEM (HRTEM) and the sizes were determined by TEM, X-ray diffraction (XRD), and in the case of NE samples, room temperature H2 and CO adsorption isotherms. Catalytic studies were carried out in homebuilt gas-phase reactors. For the nanoparticles supported on SBA-15, the catalysts are in powder form and were studied using the homebuilt systems as plug-flow reactors. In the case of nanoparticles deposited on silicon wafers, the same systems were operated as batch reactors. This dissertation has focused on the synthesis, characterization, and reaction studies of model noble metal heterogeneous catalysts. Careful control of particle size and shape has been accomplished though solution phase synthesis of Pt and Rh nanoparticles in order to elucidate further structure-reactivity relationships in noble metal catalysis.

  3. Facile Synthesis of Monodisperse Gold Nanocrystals Using Virola oleifera

    Science.gov (United States)

    Milaneze, Bárbara A.; Oliveira, Jairo P.; Augusto, Ingrid; Keijok, Wanderson J.; Côrrea, Andressa S.; Ferreira, Débora M.; Nunes, Otalíbio C.; Gonçalves, Rita de Cássia R.; Kitagawa, Rodrigo R.; Celante, Vinícius G.; da Silva, André Romero; Pereira, Ana Claudia H.; Endringer, Denise C.; Schuenck, Ricardo P.; Guimarães, Marco C. C.

    2016-10-01

    The development of new routes and strategies for nanotechnology applications that only employ green synthesis has inspired investigators to devise natural systems. Among these systems, the synthesis of gold nanoparticles using plant extracts has been actively developed as an alternative, efficient, cost-effective, and environmentally safe method for producing nanoparticles, and this approach is also suitable for large-scale synthesis. This study reports reproducible and completely natural gold nanocrystals that were synthesized using Virola oleifera extract. V. oleifera resin is rich in epicatechin, ferulic acid, gallic acid, and flavonoids (i.e., quercetin and eriodictyol). These gold nanoparticles play three roles. First, these nanoparticles exhibit remarkable stability based on their zeta potential. Second, these nanoparticles are functionalized with flavonoids, and third, an efficient, economical, and environmentally friendly mechanism can be employed to produce green nanoparticles with organic compounds on the surface. Our model is capable of reducing the resin of V. oleifera, which creates stability and opens a new avenue for biological applications. This method does not require painstaking conditions or hazardous agents and is a rapid, efficient, and green approach for the fabrication of monodisperse gold nanoparticles.

  4. Ultrasonically Aided Electrospray source for monodisperse, charged nanoparticles

    Science.gov (United States)

    Song, Weidong

    This dissertation presents a new method of producing nearly monodisperse electrospray using charged capillary standing waves. This method, based on the Ultrasonically Aided Electrospraying (UAE) technology concept invented by the author, includes the steps of dispensing a liquid on the top surface of a diaphragm so as to form a liquid film on the surface of the diaphragm, setting the diaphragm into vibration using piezoelectric transducers so as to induce capillary standing waves in the liquid film, applying electric charge to the capillary standing waves so that electrospray is extracted from the crests of the capillary standing waves. Theoretical analysis on the formation of charged particles from charged capillary standing waves at critically stable condition is performed. An experimental UAE system is designed, built, and tested and the performance of this new technology concept is assessed. Experimental results validate the capabilities of the UAE concept. The method has several applications including electric space propulsion, nano particulate technologies, nanoparticle spray coating and painting techniques, semiconductor fabrication and biomedical processes. Two example applications in electric space propulsion and nanoparticle spray coating are introduced.

  5. Spark Ignition of Monodisperse Fuel Sprays. Ph.D. Thesis

    Science.gov (United States)

    Danis, Allen M.; Cernansky, Nicholas P.; Namer, Izak

    1987-01-01

    A study of spark ignition energy requirements was conducted with a monodisperse spray system allowing independent control of droplet size, equivalent ratio, and fuel type. Minimum ignition energies were measured for n-heptane and methanol sprays characterized at the spark gap in terms of droplet diameter, equivalence ratio (number density) and extent of prevaporization. In addition to sprays, minimum ignition energies were measured for completely prevaporized mixtures of the same fuels over a range of equivalence ratios to provide data at the lower limit of droplet size. Results showed that spray ignition was enhanced with decreasing droplet size and increasing equivalence ratio over the ranges of the parameters studied. By comparing spray and prevaporized ignition results, the existence of an optimum droplet size for ignition was indicated for both fuels. Fuel volatility was seen to be a critical factor in spray ignition. The spray ignition results were analyzed using two different empirical ignition models for quiescent mixtures. Both models accurately predicted the experimental ignition energies for the majority of the spray conditions. Spray ignition was observed to be probabilistic in nature, and ignition was quantified in terms of an ignition frequency for a given spark energy. A model was developed to predict ignition frequencies based on the variation in spark energy and equivalence ratio in the spark gap. The resulting ignition frequency simulations were nearly identical to the experimentally observed values.

  6. Formation of monodisperse mesoporous silica microparticles via spray-drying.

    Science.gov (United States)

    Waldron, Kathryn; Wu, Winston Duo; Wu, Zhangxiong; Liu, Wenjie; Selomulya, Cordelia; Zhao, Dongyuan; Chen, Xiao Dong

    2014-03-15

    In this work, a protocol to synthesize monodisperse mesoporous silica microparticles via a unique microfluidic jet spray-drying route is reported for the first time. The microparticles demonstrated highly ordered hexagonal mesostructures with surface areas ranging from ~900 up to 1500 m(2)/g and pore volumes from ~0.6 to 0.8 cm(3)/g. The particle size could be easily controlled from ~50 to 100 μm from the same diameter nozzle via changing the initial solute content, or changing the drying temperature. The ratio of the surfactant (CTAB) and silica (TEOS), and the amount of water in the precursor were found to affect the degree of ordering of mesopores by promoting either the self-assembly of the surfactant-silica micelles or the condensation of the silica as two competing processes in evaporation induced self-assembly. The drying rate and the curvature of particles also affected the self-assembly of the mesostructure. The particle mesostructure is not influenced by the inlet drying temperature in the range of 92-160 °C, with even a relatively low temperature of 92 °C producing highly ordered mesoporous microparticles. The spray-drying derived mesoporous silica microparticles, while of larger sizes and more rapidly synthesized, showed a comparable performance with the conventional mesoporous silica MCM-41 in controlled release of a dye, Rhodamine B, indicating that these spray dried microparticles could be used for the immobilisation and controlled release of small molecules.

  7. Monodisperse droplet generation for microscale mass transfer studies

    Science.gov (United States)

    Roberts, Christine; Rao, Rekha; Grillet, Anne; Jove-Colon, Carlos; Brooks, Carlton; Nemer, Martin

    2011-11-01

    Understanding interfacial mass transport on a droplet scale is essential for modeling liquid-liquid extraction processes. A thin flow-focusing microfluidic channel is evaluated for generating monodisperse liquid droplets for microscale mass transport studies. Surface treatment of the microfluidic device allows creation of both oil in water and water in oil emulsions, facilitating a large parameter study of viscosity and flow rate ratios. The unusually thin channel height promotes a flow regime where no droplets form. Through confocal microscopy, this regime is shown to be highly influenced by the contact angle of the liquids with the channel. Drop sizes are found to scale with a modified capillary number. Liquid streamlines within the droplets are inferred by high speed imagery of microparticles dispersed in the droplet phase. Finally, species mass transfer to the droplet fluid is quantitatively measured using high speed imaging. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85.

  8. Thermal recycling of polystyrene and polystyrene-butadiene dissolved in a light cycle oil

    Energy Technology Data Exchange (ETDEWEB)

    Arandes, Jose M.; Erena, Javier; Olazar, Martin; Bilbao, Javier [Departamento de Ingenieria Quimica, Universidad del Pais Vasco, Apartado 644, 48080 Bilbao (Spain); Azkoiti, Miren J. [Departamento de Ingenieria Quimica y del Medio Ambiente, Universidad del Pais Vasco, Plaza de la Casilla 3, 48012 Bilbao (Spain)

    2003-12-01

    A study has been made of the cracking on a mesoporous silica of polystyrene (PS) and polystyrene-butadiene (PS-BD) dissolved in a light cycle oil (LCO) from a product stream of a commercial fluid catalytic cracking (FCC) unit. This study has been carried out in a reactor of short contact time (3 s) in the 723-823 K range. This strategy for simultaneous valorization of plastics and solvent avoids the technological problems inherent to the treatment of solid postconsumer-plastics and the limitation to heat transfer in the process of pyrolysis. The cracking of plastics has a synergistic effect on the conversion of LCO, as it contributes to increasing the yield of gasoline (C{sub 5}-C{sub 12}). The cracking of the PS/LCO blend produces high yields of styrene, whereas the cracking of the PS-BD/LCO blend produces a stream of products with petrochemical interest.

  9. Synthesis of Y2O2S:Eu3+, Mg2+, Ti4+ hollow microspheres via homogeneous precipitation route

    Directory of Open Access Journals (Sweden)

    Peng-Fei Ai, Ying-Liang Liu, Li-Yuan Xiao, Hou-Jin Wang and Jian-Xin Meng

    2010-01-01

    Full Text Available A phosphorescent material in the form of Y2O2S:Eu3+, Mg2+, Ti4+ hollow microspheres was prepared by homogeneous precipitation using monodispersed carbon spheres as hard templates. Y2O3:Eu3+ hollow microspheres were first synthesized to serve as the precursor. Y2O2S:Eu3+, Mg2+, Ti4+ powders were obtained by calcinating the precursor in a CS2 atmosphere. The crystal structure, morphology and optical properties of the composites were characterized. X-ray diffraction measurements confirmed the purity of the Y2O2S phase. Electron microscopy observations revealed that the Y2O2S:Eu3+, Mg2+, Ti4+ particles inherited the hollow spherical shape from the precursor after being calcined in a CS2 atmosphere and that they had a diameter of 350–450 nm and a wall thickness of about 50–80 nm. After ultraviolet radiation at 265 or 325 nm for 5 min, the particles emitted strong red long-lifetime phosphorescence originating from Eu3+ ions. This phosphorescence is associated with the trapping of charge carriers by Ti4+ and Mg2+ ions.

  10. Synthesis and characterization of hollow MoS{sub 2} microspheres grown from MoO{sub 3} precursors

    Energy Technology Data Exchange (ETDEWEB)

    Li Guowei, E-mail: leegowek@163.co [College of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Li Changsheng, E-mail: lichangsheng@ujs.edu.c [College of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Tang Hua; Cao Kesheng; Chen Juan; Wang Fangfei; Jin Yue [College of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2010-07-09

    Mono-dispersed molybdenum disulfide (MoS{sub 2}) microspheres with the diameter of 2-4 {mu}m have been successfully synthesized with MoO{sub 3} as precursors by a hydrothermal method. The precursors, long and smooth MoO{sub 3} macrobelts, were synthesized through a facile route. The combined techniques of X-ray diffraction (XRD), energy dispersive (EDS), scanning electron microscope (SEM), transmission electron microscope (TEM), Raman spectra, and UV-visible spectrophotometer (UV-vis) were used for characterization of the as-prepared MoS{sub 2}. It was found that the MoS{sub 2} microspheres were assembled by MoO{sub 3} macrobelts and the belts-like structure of the precursor played a crucial role on the formation of the MoS{sub 2} microstructures in our experiment. A possible formation mechanism of the hollow sphere-like MoS{sub 2} structure was preliminarily presented on the basis of the experimental facts.

  11. Uniform Yolk-Shell MoS2 @Carbon Microsphere Anodes for High-Performance Lithium-Ion Batteries.

    Science.gov (United States)

    Pan, Yunmei; Zhang, Jiajia; Lu, Hongbin

    2017-07-21

    As an electrode material for lithium-ion batteries (LIBs), MoS2 has attracted much attention because of its high capacity and low cost. However, the rational design of a novel electrode structure with a high capacity, fast charge/discharge rate, and long cycling lifetime remains a great challenge. Herein, a environmentally friendly etching strategy is reported for the construction of monodisperse, inner void-controlled yolk-shell MoS2 @carbon microspheres. The resulting anode reveals an initial discharge capacity up to 1813 mAh g(-1) , a high reversible capacity (1016 mAh g(-1) ), excellent cycling stability (200 cycles), and superior rate performance. Such microspheres consist of nanosized MoS2 yolks (≈280 nm), porous carbon shells (≈25 nm) and well-controlled internal voids in between, opening a new pathway for the optimization of the electrochemical properties of MoS2 -based anodes without sacrificing their capacity. In addition, this etching strategy offers a new method for the development of functional, hollow MoS2 -based composites. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. High Resolutions Obtained by Microspheres, and Phase Contrast Microscope with a Microsphere

    CERN Document Server

    Ben-Aryeh, Y

    2015-01-01

    High resolutions obtained in optical systems with microspheres are studied by Helmholtz equation and boundary conditions for the EM fields. The large lateral spatial wave vectors of the evanescent waves, which include information on the fine structures of the object, are converted at the microsphere surface to smaller spatial wave vectors. Due to reduction in the magnitudes of these spatial wave vectors a part of the EM waves propagate in the microsphere without decay, but preserve the fine structures which can be recovered in the image plane. A new method for measuring phase objects, like those of semi-transparent biological tissues, with high resolutions is described by an optical system composed of a combination of the microsphere with an interferometer.

  13. Preparation of biodegradable porous poly(butylene succinate microspheres

    Directory of Open Access Journals (Sweden)

    Pepić Dragana

    2008-01-01

    Full Text Available The aim of this study was to determine the optimal conditions for the fabrication of porous microspheres based on poly(butylene succinate, PBS. The biodegradable non-porous PBS microspheres were prepared by the oil-in-water (o/w emulsion solvent evaporation method using poly(vinyl alcohol, PVA, as the surfactant. Fabrication conditions, such as stirring rate, organic/aqueous ratio, PBS concentration and surfactant (PVA concentration, which have an important influence on both the particle size and the morphology of the microspheres, were varied. Scanning electron microscopy, SEM, observations confirmed the size, size distribution and surface morphology of the microspheres. The optimal conditions for the preparation of the non-porous microspheres were found to be: concentration the PBS solution, 10 mass%; PVA concentration, 1 mass%; the organic/ aqueous ratio CHCl3/H2O = 1/20 and stirring rate 800 rpm. Porous PBS microspheres were fabricated under the optimal conditions using various amounts of hexane and poly(ethylene oxide, PEO, as porogens. The influence of the amount of porogen on the pore size and the particle size was investigated using SEM and the apparent density. The microspheres exhibited various porosities and the pore sizes. The average particle size of the microspheres with PEO as the porogen was from 100 to 122μm and that of the microspheres with hexane as the porogen was from 87 to 97μm. The apparent density of the porous microspheres with PEO as the porogen, from 0.16 to 0.23 g/cm3, was much smaller than the non-porous microspheres, 0.40 g/cm3. In the in vitro degradation experiments, the porous microspheres were incubated in phosphate buffer solution (pH 7 at 37°C. After incubating for one month, the microspheres showed significant extent of the hydrolytic degradation of the porous PBS microspheres.

  14. DYNAMIC MECHANICAL RESPONSE OF CRAZES IN POLYSTYRENE

    Institute of Scientific and Technical Information of China (English)

    DING Jianfu; XUE Gi; CHENG Rongshi

    1994-01-01

    Dynamic mechanical analysis was used to study the mechanical properties and microstructure of crazes in polystyrene produced in air or in methanol at different temperatures. A new loss peak was found at about 82℃ ,which is assigned to glass transition peak of craze fibrils. The decrease of glass transition temperature of polymer in craze fibrils is due to the high values of surface to volume ratio. The glass transition temperature ratio of craze fibrils to bulk material(Tg'/Tg) has been expressed as a function of the fibrils diameter(d). From Tg'of craze fibrils ,the value of fibril diameter can be calculated. Annealing the crazed specimen at room temperature makes the fibrils plastically deform and cause the fibrils to thin slightly, whereas annealing the crazed specimen at the temperature near Tg of the craze fibrils makes the fibrils bundle together.

  15. Tribology of Graphite-Filled Polystyrene

    Directory of Open Access Journals (Sweden)

    Raffaele Gilardi

    2016-06-01

    Full Text Available Self-lubricating polymer compounds are currently used for a wide range of applications such as bearings, gears, and water meters. Under severe conditions such as high pressure, high velocity, and/or high temperatures, the material fails (PV limit. In this study, we investigated the effect of graphite on the tribological properties of polystyrene (PS with “ball-on-three-plates” tests. Graphite-filled PS plates were produced via an internal mixer and compression molding. Unhardened steel (1.4401 and nylon (PA66 balls were used for the tribological tests. Our results indicate that graphite loading, graphite type, and particle size have a big influence on the friction coefficient, the wear resistance, and the PV limit of PS both against steel and PA66. In particular, primary synthetic graphite performs better than secondary synthetic graphite due to the higher degree of crystallinity.

  16. Polyethylene glycol-grafted polystyrene particles.

    Science.gov (United States)

    Meng, Fenghua; Engbers, Gerard H M; Feijen, Jan

    2004-07-01

    Densely pegylated particles that can serve as a model system for artificial cells were prepared by covalently grafting amino polyethylene glycol (PEG, molecular weight 3400 or 5000) onto carboxyl polystyrene particles (PS-COOH) using carbodiimide chemistry. PEG-modified particles (PS-PEG) were characterized by determination of the PEG surface concentration, zeta-potential, size, and morphology. Under optimized grafting conditions, a dense "brush-like" PEG layer was formed. A PEG surface concentration of approximately 60 pmol/cm2, corresponding with an average distance between grafted PEG chains of approximately 17 A can be realized. It was shown that grafting of PEG onto PS-COOH reduced the adsorption of proteins from human plasma (85 vol %) in phosphate-buffered saline up to 90%.

  17. Correlated dewetting patterns in thin polystyrene films

    Energy Technology Data Exchange (ETDEWEB)

    Neto, Chiara [Department of Applied Physics, University of Ulm, Albert Einstein Allee 11, D-89069 Ulm (Germany); Jacobs, Karin [Department of Applied Physics, University of Ulm, Albert Einstein Allee 11, D-89069 Ulm (Germany); Seemann, Ralf [Department of Applied Physics, University of Ulm, Albert Einstein Allee 11, D-89069 Ulm (Germany); Blossey, Ralf [Centre for Bioinformatics, Saarland University, PO Box 151150, D-66041 Saarbruecken (Germany); Becker, Juergen [Institute of Applied Mathematics, University of Bonn, Beringstr. 6, D-53115 Bonn (Germany); Gruen, Guenther [Institute of Applied Mathematics, University of Bonn, Beringstr. 6, D-53115 Bonn (Germany)

    2003-01-15

    We describe preliminary results of experiments and simulations concerned with the dewetting of thin polystyrene films (thickness < 7 nm) on top of silicon oxide wafers. In the experiments we scratched an initially flat film with an atomic force microscopy (AFM) tip, producing dry channels in the film. Dewetting of the films was imaged in situ using AFM and a correlated pattern of holes ('satellite holes') was observed along the rims bordering the channels. The development of this complex film rupture process was simulated and the results of experiments and simulations are in good agreement. On the basis of these results, we attempt to explain the appearance of satellite holes and their positions relative to pre-existing holes.

  18. Correlated dewetting patterns in thin polystyrene films

    CERN Document Server

    Neto, C; Seemann, R; Blossey, R; Becker, J; Grün, G

    2003-01-01

    We describe preliminary results of experiments and simulations concerned with the dewetting of thin polystyrene films (thickness < 7 nm) on top of silicon oxide wafers. In the experiments we scratched an initially flat film with an atomic force microscopy (AFM) tip, producing dry channels in the film. Dewetting of the films was imaged in situ using AFM and a correlated pattern of holes ('satellite holes') was observed along the rims bordering the channels. The development of this complex film rupture process was simulated and the results of experiments and simulations are in good agreement. On the basis of these results, we attempt to explain the appearance of satellite holes and their positions relative to pre-existing holes.

  19. Nanoporous polystyrene fibers for oil spill cleanup.

    Science.gov (United States)

    Lin, Jinyou; Shang, Yanwei; Ding, Bin; Yang, Jianmao; Yu, Jianyong; Al-Deyab, Salem S

    2012-02-01

    The development of oil sorbents with high sorption capacity, low cost, scalable fabrication, and high selectivity is of great significance for water environmental protection, especially for oil spillage on seawater. In this work, we report nanoporous polystyrene (PS) fibers prepared via a one-step electrospinning process used as oil sorbents for oil spill cleanup. The oleophilic-hydrophobic PS oil sorbent with highly porous structures shows a motor oil sorption capacity of 113.87 g/g, approximately 3-4 times that of natural sorbents and nonwoven polypropylene fibrous mats. Additionally, the sorbents also exhibit a relatively high sorption capacity for edible oils, such as bean oil (111.80 g/g) and sunflower seed oil (96.89 g/g). The oil sorption mechanism of the PS sorbent and the sorption kinetics were investigated. Our nanoporous material has great potential for use in wastewater treatment, oil accident remediation and environmental protection.

  20. Microbial assisted High Impact Polystyrene (HIPS) degradation.

    Science.gov (United States)

    Mohan, Arya J; Sekhar, Vini C; Bhaskar, Thallada; Nampoothiri, K Madhavan

    2016-08-01

    The efficacy of newly isolated Pseudomonas and Bacillus strains to degrade brominated High Impact Polystyrene (HIPS) was investigated. Viability of these cultures while using e-plastic as sole carbon source was validated through Triphenyl Tetrazolium Chloride (TTC). Four days incubation of HIPS emulsion with Bacillus spp. showed 94% reduction in turbidity and was 97% with Pseudomonas spp. Confirmation of degradation was concluded by HPLC, NMR, FTIR, TGA and weight loss analysis. NMR spectra of the degraded film revealed the formation of aliphatic carbon chain with bromine and its release. FTIR analysis of the samples showed a reduction in CH, CO and CN groups. Surface changes in the brominated HIPS film was visualized through SEM analysis. Degradation with Bacillus spp showed a weight loss of 23% (w/w) of HIPS film in 30days.

  1. ANALYSIS DEGRADATION OF POLYSTYRENE WITH MONTMORILLONITE NANOFILLERS

    Directory of Open Access Journals (Sweden)

    Maria Mihalikova

    2014-01-01

    Full Text Available The paper is focused on the experimental investigation of the montmorillonite nanofillers effect on deformation properties of polystyrene KRASTEN 171. In some cases, combination of a low amount of clay with dispersed polymeric phase may cause synergistic effects leading to very fair balance of mechanical behaviour. This seems to be a consequence of complex influencing the multiphase system by clay such as modification of components (reinforcement and parameters of the interface accompanied by influencing the dynamic phase behaviour, i.e., the compactibilizing effect. The paper analyses the effect of nanocomposites and type of the material on the individual measured parameters, relations between them, strength and deformation behaviour. Deformation was evaluated by non-contact videoextensometry method

  2. Phase Segregation in Polystyrene?Polylactide Blends

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Bonnie; Hitchcock, Adam; Brash, John; Scholl, Andreas; Doran, Andrew

    2010-06-09

    Spun-cast films of polystyrene (PS) blended with polylactide (PLA) were visualized and characterized using atomic force microscopy (AFM) and synchrotron-based X-ray photoemission electron microscopy (X-PEEM). The composition of the two polymers in these systems was determined by quantitative chemical analysis of near-edge X-ray absorption signals recorded with X-PEEM. The surface morphology depends on the ratio of the two components, the total polymer concentration, and the temperature of vacuum annealing. For most of the blends examined, PS is the continuous phase with PLA existing in discrete domains or segregated to the air?polymer interface. Phase segregation was improved with further annealing. A phase inversion occurred when films of a 40:60 PS:PLA blend (0.7 wt percent loading) were annealed above the glass transition temperature (Tg) of PLA.

  3. Nanoscale Morphology of Sulfonated Polystyrene Ionomers

    Science.gov (United States)

    Zhou, Nancy C.; Winey, Karen I.

    2007-03-01

    We have applied our scanning transmission electron microscopy (STEM) methods to investigate the size, shape and spatial distribution of the ionic, nanoscale aggregates in poly(styrene-ran-styrene sulfonate) (P(S-SSx)) ionomers. This analytical electron microscopy method minimizes phase contrast that can obscure nano-scale features and accentuates differences in atomic number. We recently reported quantitative agreement between STEM and X-ray scattering results in a Cu-neutralized poly(styrene-ran-methacrylic acid) (SMAA) ionomer with respect to the size of the ionic aggregates and their number density. For this study, P(S-SSx) ionomers were prepared by solution neutralizing with metal acetates, solution casting, and annealing. Initial STEM results from P(S-SS0.019) fully neutralized with Zn indicate a uniform distribution of monodisperse spherical aggregates. Combining direct imaging and X-ray scattering of P(S-SSx) ionomers, we will investigate the effect of cation type and level of neutralization.

  4. HALOMETHYLATION OF POLYSTYRENE AND SUBSEQUENT PYRIDINATION VIA A HOMOLYTIC PATHWAY

    Institute of Scientific and Technical Information of China (English)

    Sa(a)d Moulay; Nadia Mehdi

    2006-01-01

    Chloromethylation of polystyrene (PS) with two different chloromethylating systems methylal/thionyl chloride and paraformaldehyde/trimethylchlorosilane was studied. Soluble chloromethylated polystyrene with a degree of substitution of 89% was obtained. The Conant-Finkelstein reaction on the chloromethylated PS afforded soluble iodomethylated polystyrene with a degree of substitution as high as 96%. The reaction conditions of Minisci were employed to radically pyridinate PS via its iodomethylated derivative. Polyelectrolytes were formed which could be converted to normal polymers by treatment with a 20% aqueous solution of NaOH.

  5. Characterization of Pectin Nanocoatings at Polystyrene and Titanium Surfaces

    DEFF Research Database (Denmark)

    Gurzawska, Katarzyna; Dirscherl, Kai; Yihua, Yu;

    2013-01-01

    study was to physically characterize and compare polystyrene and titanium surfaces nanocoated with different Rhamnogalacturonan-Is (RG-I) and to visualize RG-I nanocoatings. RG-Is from potato and apple were coated on aminated surfaces of polystyrene, titianium discs and titanium implants...... wettability, without any major effect on surface roughness (Sa, Sdr). Furthermore, we demonstrated that it is possible to visualize the pectin RG-Is molecules and even the nanocoatings on titanium surfaces, which have not been presented before. The comparison between polystyrene and titanium surface showed...

  6. Beat-Frequency/Microsphere Medical Ultrasonic Imaging

    Science.gov (United States)

    Yost, William T.; Cantrell, John H.; Pretlow, Robert A., III

    1995-01-01

    Medical ultrasonic imaging system designed to provide quantitative data on various flows of blood in chambers, blood vessels, muscles, and tissues of heart. Sensitive enough to yield readings on flows of blood in heart even when microspheres used as ultrasonic contrast agents injected far from heart and diluted by circulation of blood elsewhere in body.

  7. Bilayer Tablet via Microsphere: A Review

    Directory of Open Access Journals (Sweden)

    Piyushkumar Vinubhai Gundaraniya

    2013-01-01

    Full Text Available The aim of the present work is to develop bilayer tablets containing sustained release microspheres as one layer and immediate release as another layer. The proposed dosage form is intended to decrease the dosing frequency and the combined administration of an anti-diabetic agent. Several pharmaceutical companies are currently developing bi-layer tablets, for a variety of reasons: patent extension, therapeutic, marketing to name a few. To reduce capital investment, quite often existing but modified tablet presses are used to develop and produce such tablets. One such approach is using microspheres as carriers for drugs also known as micro particles. It is the reliable means to deliver the drug to the target site with specificity, if modified, and to maintain the desired concentration at the site of interest. Microspheres received much attention not only for prolonged release, but also for targeting of anti-diabetic drugs. Bilayer tablet via microsphere is new era for the successful development of controlled release formulation along with various features to provide a way of successful drug delivery system. Especially when in addition high production output is required. An attempt has been made in this review article to introduce the society to the current technological developments in bilayer and floating drug delivery system.

  8. Tumor Vaccination With Cytokine-Loaded Microspheres

    Science.gov (United States)

    2005-12-01

    buffer (1% hydroxypropylmethylcellulose [DOW Co., Midlands, MI, USA] and 1% Pluronic F127 [Sigma] in phosphate-buffered saline [PBS], pH 7.2). Control mice...hydration buffer (1% hydroxypropylmethylcellulose (Dow) and 1% Pluronic F-127 (Sigma- Aldrich) in PBS, pH 7.2). Control mice received blank microspheres

  9. Arabinoxylan Microspheres: Structural and Textural Characteristics

    Directory of Open Access Journals (Sweden)

    Yolanda López-Franco

    2013-04-01

    Full Text Available The aim of this research was to study the structural and textural characteristics of maize bran arabinoxylan (MBAX microspheres. The laccase-induced cross-linking process was monitored by storage (G' and loss (G'' moduli changes in a 4% (w/v MBAX solution. The G' and G'' values at the plateau region were 215 and 4 Pa, respectively. After gelation, the content of ferulic acid dimers decreased from 0.135 to 0.03 µg/mg MBAX, suggesting the formation of ferulated structures unreleased by mild alkaline hydrolysis. MBAX microspheres presented an average diameter of 531 µm and a swelling ratio value (q of 18 g water/g MBAX. The structural parameters of MBAX microspheres were calculated from equilibrium swelling experiments, presenting an average mesh size of 52 nm. Microstructure and textural properties of dried MBAX microspheres were studied by scanning electron microscopy and nitrogen adsorption/desorption isotherms, respectively, showing a heterogeneous mesoporous and macroporous structure throughout the network.

  10. Encapsulated PDMS microspheres with reactive handles

    DEFF Research Database (Denmark)

    Gonzalez, Lidia; Ma, Baoguang; Li, Li

    2014-01-01

    Cured poly(dimethyl siloxane) microspheres are prepared by an emulsion polymerization reaction of silicone droplets in a continuous aqueous phase. The commonly used PDMS elastomer, Sylgard 184 from Dow Corning, is used as the dispersed phase. PDMS is polymerized and cross-linked by reacting vinyl...

  11. Sulfonated polystyrene as a new gradient-index medium for light-focusing elements.

    Science.gov (United States)

    Jung, S D; Hwang, W Y; Song, S H; Lee, el-H; Lee, J I; Shim, H K

    1995-06-01

    We have discovered that the sulfonation of polystyrene can form a gradient-index medium useful for lightfocusing purposes. We found that the refractive index of sulfonated polystyrene varies with the degree of sulfonation and that the refractive index of the fully sulfonated polystyrene decreased by approximately 0.06 at 0.633 microm from that of pure polystyrene.

  12. Composition and structure of calcium aluminosilicate microspheres

    Science.gov (United States)

    Sharonova, O. M.; Oreshkina, N. A.; Zhizhaev, A. M.

    2017-06-01

    The composition was studied of calcium aluminosilicate microspheres of three morphological types in high-calcium fly ash from combustion of brown coal from the Kansk-Achinsk basin in slag-tap boilers at temperatures from 1400 to 1500°C and sampled in the first field of electrostatic precipitators at the Krasnoyarsk Cogeneration Power Station no. 2 (TETs-2). Gross compositions and the composition of local areas were determined using a scanning electron microscopy technique and an energy-dispersive analysis with full mapping of globules. With a high content of basic oxides O ox (68 to 79 wt %) and a low content of acid oxides K ox (21 to 31 wt %), type 1 microspheres are formed. They consist of heterogeneous areas having a porous structure and crystalline components in which the content of CaO, SiO2, or Al2O3 differs by two to three times and the content of MgO differs by seven times. With a lower content of O ox (55 to 63 wt %) and an elevated content of K ox (37 to 45 wt %), type 2 microspheres are formed. They are more homogeneous in the composition and structure and consist of similar crystalline components. Having a close content of O ox (46 to 53 wt %) and K ox (47 to 54 wt %), type 3 microspheres, which are a dense matter consisting of amorphous substance with submicron- and nanostructure of crystalline components, are formed. The basic precursor in formation of high-calcium aluminosilicate microspheres is calcium from the organomineral matter of coals with various contribution of Mg, Fe, S, or Na from the coal organic matter and Al, Fe, S, or Si in the form of single mineral inclusions in a coal particle. On the basis of the available data, the effect was analyzed of the composition of a CaO-MgO-Al2O3-SiO2-FeO system on the melting and viscous properties of the matter in microspheres and formation of globules of different morphology. The results of this analysis will help to find a correlation with properties of microspheres in their use as functional

  13. Preparation of Hollow Porous HAP Microspheres as Drug Delivery Vehicles

    Institute of Scientific and Technical Information of China (English)

    WANG Qing; HUANG Wenhai; WANG Deping

    2007-01-01

    Hollow HAP microspheres in sub-millimeter size were prepared and investigated as a drug delivery vehicle. The LCB (lithium-calcium borate) glass microspheres, which were made through flame spray process, were chosen as precursor for hollow HAP microspheres. The LCB glass microspheres reacted with phosphate buffer (K2HPO4) solution for 5 days at 37 ℃. During the reaction the Ca-P-OH compound precipitated on the surface of LCB glass microspheres and formed porous shells. Then the microspheres turned to be hollow ones with the same diameter as the glass microspheres after LCB glass run out in the chemical reaction. After heat-treated at 600 ℃ for 4 h, the Ca-P-OH compound became HAP, thus the hollow HAP microspheres were produced. The mechanism of forming hollow HAP microspheres through the chemical reaction between phosphate buffer and LCB glass was confirmed by the XRD analysis. The microstructure characteristics of the hollow, porous microspheres were observed by SEM.

  14. PLGA/alginate composite microspheres for hydrophilic protein delivery.

    Science.gov (United States)

    Zhai, Peng; Chen, X B; Schreyer, David J

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate.

  15. Controlled synthesis and magnetic properties of monodispersed ceria nanoparticles

    Directory of Open Access Journals (Sweden)

    Sumeet Kumar

    2015-02-01

    Full Text Available In the present study, monodispersed CeO2 nanoparticles (NPs of size 8.5 ± 1.0, 11.4 ± 1.0 and 15.4 ± 1.0 nm were synthesized using the sol-gel method. Size-dependent structural, optical and magnetic properties of as-prepared samples were investigated by X-ray diffraction (XRD, field emission scanning electron microscope (FE-SEM, high resolution transmission electron microscopy (HR-TEM, ultra-violet visible (UV-VIS spectroscopy, Raman spectroscopy and vibrating sample magnetometer (VSM measurements. The value of optical band gap is calculated for each particle size. The decrease in the value of optical band gap with increase of particle size may be attributed to the quantum confinement, which causes to produce localized states created by the oxygen vacancies due to the conversion of Ce4+ into Ce3+ at higher calcination temperature. The Raman spectra showed a peak at ∼461 cm-1 for the particle size 8.5 nm, which is attributed to the 1LO phonon mode. The shift in the Raman peak could be due to lattice strain developed due to variation in particle size. Weak ferromagnetism at room temperature is observed for each particle size. The values of saturation magnetization (Ms, coercivity (Hc and retentivity (Mr are increased with increase of particle size. The increase of Ms and Mr for larger particle size may be explained by increase of density of oxygen vacancies at higher calcination temperature. The latter causes high concentrations of Ce3+ ions activate more coupling between the individual magnetic moments of the Ce ions, leading to an increase of Ms value with the particle size. Moreover, the oxygen vacancies may also produce magnetic moment by polarizing spins of f electrons of cerium (Ce ions located around oxygen vacancies, which causes ferromagnetism in pure CeO2 samples.

  16. Controlled synthesis and magnetic properties of monodispersed ceria nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sumeet; Ojha, Animesh K. [Department of Physics, Motilal Nehru National Institute of Technology, Allahabad-211004 (India); Srivastava, Manish, E-mail: 84.srivastava@gmail.com, E-mail: manish-mani84@rediffmail.com [Department of Physics and Astrophysics, University of Delhi, Delhi-110007 (India); Singh, Jay [Department of Applied Chemistry and Polymer Technology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042 (India); Layek, Samar [Department of Physics, Indian Institute of Technology, Kanpur 208016 (India); Yashpal, Madhu [Electron Microscope Facility, Department of Anatomy Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005 (India); Materny, Arnulf [Center for Functional Materials and Nanomolecular Science, Jacobs University Bremen, Campus Ring, 28759 Bremen (Germany)

    2015-02-15

    In the present study, monodispersed CeO{sub 2} nanoparticles (NPs) of size 8.5 ± 1.0, 11.4 ± 1.0 and 15.4 ± 1.0 nm were synthesized using the sol-gel method. Size-dependent structural, optical and magnetic properties of as-prepared samples were investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), high resolution transmission electron microscopy (HR-TEM), ultra-violet visible (UV-VIS) spectroscopy, Raman spectroscopy and vibrating sample magnetometer (VSM) measurements. The value of optical band gap is calculated for each particle size. The decrease in the value of optical band gap with increase of particle size may be attributed to the quantum confinement, which causes to produce localized states created by the oxygen vacancies due to the conversion of Ce{sup 4+} into Ce{sup 3+} at higher calcination temperature. The Raman spectra showed a peak at ∼461 cm{sup -1} for the particle size 8.5 nm, which is attributed to the 1LO phonon mode. The shift in the Raman peak could be due to lattice strain developed due to variation in particle size. Weak ferromagnetism at room temperature is observed for each particle size. The values of saturation magnetization (Ms), coercivity (Hc) and retentivity (Mr) are increased with increase of particle size. The increase of Ms and Mr for larger particle size may be explained by increase of density of oxygen vacancies at higher calcination temperature. The latter causes high concentrations of Ce{sup 3+} ions activate more coupling between the individual magnetic moments of the Ce ions, leading to an increase of Ms value with the particle size. Moreover, the oxygen vacancies may also produce magnetic moment by polarizing spins of f electrons of cerium (Ce) ions located around oxygen vacancies, which causes ferromagnetism in pure CeO{sub 2} samples.

  17. PLGA microspheres encapsulating siRNA.

    Science.gov (United States)

    De Rosa, Giuseppe; Salzano, Giuseppina

    2015-01-01

    The therapeutic use of small interfering RNA (siRNA) represents a new and powerful approach to suppress the expression of pathologically genes. However, biopharmaceutical drawbacks, such as short half-life, poor cellular uptake, and unspecific distribution into the body, hamper the development of siRNA-based therapeutics. Poly(lactide-co-glycolide), (PLGA) microspheres can be a useful tool to overcome these issues. siRNA can be encapsulated into the PLGA microspheres, which protects the loaded nucleic acid against the enzymatic degradation. Moreover, PLGA microspheres can be injected directly into the action site, where the siRNA can be released in controlled manner, thus avoiding the need of frequent invasive administrations. The complete biodegradability of PLGA to monomers easily metabolized by the body, and its approval by FDA and EMA for parenteral administration, assure the safety of this copolymer and do not require the removal of the device after the complete drug release. In chapter, a basic protocol for the preparation of PLGA microspheres encapsulating siRNA is described. This protocol is based on a double emulsion/solvent evaporation technique, a well known and easy to reproduce method. This specific protocol has been developed to encapsulate a siRNA anti-TNFα in PLGA microspheres, and it has been designed and optimized to achieve high siRNA encapsulation efficiency and slow siRNA release in vitro. However, it can be extended also to other siRNA as well as other RNA or DNA-based oligonucleotides (miRNA, antisense, decoy, etc.). Depending on the applications, chemical modifications of the backbone and site-specific modification within the siRNA sequences could be required.

  18. Chemical Recycling of Expanded Polystyrene Waste: Synthesis of Novel Functional Polystyrene-Hydrazone Surface for Phenol Removal

    Directory of Open Access Journals (Sweden)

    Ali N. Siyal

    2013-01-01

    Full Text Available Expanded polystyrene (EPS waste was chemically recycled to a novel functional polystyrene-hydrazone (PSH surface by acetylation of polystyrene (PS and then condensation with phenyl hydrazine. The synthesized surface was characterized by the FT-IR and elemental analysis. Synthesized novel functional PSH surface was successfully applied for the treatment of phenol-contaminated industrial wastewater by solid-phase extraction. Multivariant sorption optimization was achieved by factorial design approach. 99.93% of phenol was removed from aqueous solution. FT-IR study showed the involvement of nitrogen of hydrazone moiety of synthesized surface for the uptake of phenol through the hydrogen bonding.

  19. Mortar modified with sulfonated polystyrene produced from waste plastic cups

    Directory of Open Access Journals (Sweden)

    L. A. C. MOTTA

    Full Text Available Abstract In this work, we studied the addition of sulfonated polystyrene produced from waste plastic cups as an admixture for mortars. Mortars were analyzed with polystyrene content of 0.0; 0.2; 0.6; 1.0 and 1.4% in relation to the cement mass. The influence of polystyrene on the mortars' properties was evaluated by the consistency index, water retention, water absorption, porosity, elasticity modulus, compressive strength, flexural strength, bond tensile strength and microscopy. The increase in the sulfonated polystyrene content decreased the elasticity modulus of the mortar and, despite higher porosity, there was a reduction of water absorption by capillarity. In relation to mortar without admixture, the modified mortar showed an increase in water retention and consistency index, and a large increase in flexural strength and bond tensile strength. The significant increase of bond tensile strength (214% with admixture 1% highlights the potential of the produced material as an adhesive mortar.

  20. Preparation and Structural Characterization of Polystyrene-Rectorite Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    Fang Peng-fei; Liu Li-ming; Zhang Ming; Zhang Shao-ping; Wang Bo; Wang Shao-jie

    2003-01-01

    The polystyrene/rectorite nanocomposites were prepared by free radical polymerization of styrene containing dispersed organophilic rectorite. The structures and thermal properties of these hybrids have been investigated by X-ray diffraction (XRD), fourier transform infrared (FT-IR), positron annihilation spectroscopy (PAS) and thermal gravimetric analysis (TGA) techniques. It was found that exfoliation of rectorite in polystyrene (PS) matrix was achieved. The average free-volume radius in the PS/clay nanocomposites is generally same as that in PS. Along with increment of rectorite contents, the interface between rectorite and polystyrene matrix increases, and the free-volume concentration decreases obviously. And the polystyrene nanocomposites have higher thermal decomposition temperature than pure PS.

  1. Preparation and Structural Characterization of Polystyrene-Rectorite Nanocornposites

    Institute of Scientific and Technical Information of China (English)

    FangPeng-fei; LiuLi-ming; ZhangMlng; ZhangShao-ping; WangBo; WangShao-jie

    2003-01-01

    The polystyrene/reetorite nanocomposites were prepared by free radical polymerization of styrene containing dispersed organophilic rectorite. The structures and thermal properties of these hybrids have been investigated by X-ray diffraction (XRD), fourier transform infrared (FT-IR), positron annihilation spectroscopy (PAS) and thermal gmvimetric analysis (TGA) techniques. It was found that exfoliation of reetorite in polystyrene (PS) matrix was achieved. The average free-volume radius in the PS/clay nanocomposites is generally same as that in PS. Along with increment of reetorite contents, the interface between reetorite and polystyrene matrix increases, and the free-volume concentration decreases obviously. And the polystyrene nanocomposites have higher thermal deeomrosition temoemture than oure PS.

  2. Highly selective removal of Hg2+ and Pb2+ by thiol-functionalized Fe3O4@metal-organic framework core-shell magnetic microspheres

    Science.gov (United States)

    Ke, Fei; Jiang, Jing; Li, Yizhi; Liang, Jing; Wan, Xiaochun; Ko, Sanghoon

    2017-08-01

    In this work, we report a novel type of thiol-functionalized magnetic core-shell metal-organic framework (MOF) microspheres that can be potentially used for selective removal of Hg2+ and Pb2+ in the presence of other background ions from wastewater. The monodisperse Fe3O4@Cu3(btc)2 core-shell magnetic microspheres have been fabricated by a versatile step-by-step assembly strategy. Further, the thiol-functionalized Fe3O4@Cu3(btc)2 magnetic microspheres were successfully synthesized by utilizing a facile postsynthetic strategy. Significantly, the thiol-functionalized Fe3O4@Cu3(btc)2 magnetic microspheres exhibit remarkably selective adsorption affinity for Hg2+ (Kd = 5.98 × 104 mL g-1) and Pb2+ (Kd = 1.23 × 104 mL g-1), while a weaker binding affinity occurred for the other background ions such as Ni2+, Na+, Mg2+, Ca2+, Zn2+ and Cd2+. The adsorption kinetics follow the pseudo-second-order rate equation and with an almost complete removal of Hg2+ and Pb2+ from the mixed heavy metal ions wastewater (0.5 mM) within 120 min. Moreover, this adsorbent can be easily recycled because of the presence of the magnetic Fe3O4 core. This work provides a promising functionalized porous magnetic Fe3O4@MOF-based adsorbent with easy recycling property for the selective removal of heavy metal ions from wastewater.

  3. Synthesis of the silica@graphene oxide microspheres with core-shell structure as drug carriers%用作药物载体的氧化石墨烯包裹SiO2微球的制备

    Institute of Scientific and Technical Information of China (English)

    相昊天; 李延报; 姚兴星; 江芸; 陆春华; 许仲梓

    2013-01-01

    The silica@graphene oxide (SiO2-NH2@GO)microspheres with core-shell structure were synthesized through the electrostatic interactions by encapsulation of graphene oxide on the surface of amino modified silica microspheres.The as-prepared microspheres were characterized by FT-IR,SEM,TEM and UV,etc.The re-sults show that the SiO2-NH2@GO microspheres are monodispersed with the diameter of 550 nm.GO wrapped on SiO2 surface evenly which were examined by SEM and TEM.Compared with pure SiO2 ,the drug loading of SiO2-NH2@GO microspheres was increased highly from 42.9% to 68.8% after immersed in ibuprofen solu-tion,the 92% drug was released after soaked for 24 h and the administration time was prolonged about 20 h. This implies that the monodispersed SiO2-NH2@GO microspheres synthesized in this work have potential usage as drug carriers in the biomedical fields.%在经氨基修饰的Si O 2微球表面包裹氧化石墨烯,制备核壳结构的 SiO2-NH2@GO 复合微球。采用傅立叶转换-红外光谱仪(FT-IR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和紫外分光光度计(UV)等对样品进行表征与分析。结果表明,SiO2-NH2@GO 复合微球具有良好的单分散性(粒径约为550 nm),并且 GO 均匀地包裹在 SiO2表面。与纯SiO2相比,SiO2-NH2@GO 通过布洛芬溶液浸泡载药的载药率有了较大提高,从42.9%提高到了68.8%,并且表现出更好的缓释性,24 h 累积释药量达到92%,给药时间延长20 h左右。表明 SiO2-NH2@GO复合微球有望成为一种新的药物载体。

  4. The charge memory effect in polystyrene-based composite structures

    Science.gov (United States)

    Belogorokhov, I. A.; Belogorokhova, L. I.; Kotova, M. S.; Dronov, M. A.

    2016-09-01

    It is shown that the addition of light-sensitive particles to a polystyrene matrix enables control over processes of resistive voltage switching in the composite material, which involve photoinduced transitions between states with different conductivities. This specific feature of polymeric composite materials based on polystyrene and heterocyclic rings can be accounted for in terms of the model of charge accumulation and that of conducting channels.

  5. Searching for new green wavelength shifters in polystyrene

    Energy Technology Data Exchange (ETDEWEB)

    Pla-Dalmau, A.; Foster, G.W.; Zhang, G.

    1993-12-01

    A series of commercially available fluorescent compounds was tested as wavelength shifters in polystyrene for the tile/fiber SDC calorimeter. The objective was to find a green-fluorescing compound with short decay time (3--7 ns). Transmittance, fluorescence, and decay time measurements were performed in order to characterize each compound in polystyrene. These samples were also studies for radiation-induced damage.

  6. Studies on irradiation stability of polystyrene by NMR

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xin; SUN Wan-Fu; XIE Cheng-Xi

    2004-01-01

    The irradiation stability of polystyrene (PS) was studied by 13C and 1H NMR spectra, Nuclear Overhauser Relaxation (NOE) and 13C NMR spin-lattice relaxation time (T1). The results indicate that 13C and 1H NMR chemical shifts, NOE and T1 were almost invariant with the increase of irradiation dose. This shows that polystyrene is particularly stable within 2.5 kGy doses and the mechanism of its stability is discussed.

  7. Pluronic F127/chitosan blend microspheres for mucoadhesive drug delivery

    Science.gov (United States)

    Gu, W. Z.; Hu, X. F.

    2017-01-01

    Pluronic F127/chitosan blend microspheres were prepared via emulsification and cross-linking process using glutaraldehyde as a cross-linker. Compared with chitosan microspheres fabricated under the same experimental conditions, blend microspheres exhibited better physical stability and higher swelling capacity. Puerarin, a traditional Chinese medicine, was incorporated into microparticlesas the model drug. The in vitro release of puerarin from blend microspheres was reduced because of the improved compatibility of the drug with the matrices. According to the results from in vitro adhesion experiments, mucoadhesive behavior of blend microspheres on a mucosa-like surface was similar to that of chitosan microspheres, despite their good ability of anti-protein absorption in solution.

  8. PLGA and PHBV Microsphere Formulations and Solid-State Characterization

    DEFF Research Database (Denmark)

    Yang, Chiming; Plackett, David; Needham, David

    2009-01-01

    To develop and characterize the solid-state properties of poly(DL-lactic-co-glycolic acid) (PLGA) and poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) microspheres for the localized and controlled release of fusidic acid (FA). The effects of FA loading and polymer composition on the mean...... diameter, encapsulation efficiency and FA released from the microspheres were determined. The solid-state and phase separation properties of the microspheres were characterized using DSC, XRPD, Raman spectroscopy, SEM, laser confocal and real time recording of single microspheres formation. Above a loading...... of 1% (w/w) FA phase separated from PLGA polymer and formed distinct spherical FA-rich amorphous microdomains throughout the PLGA microsphere. For FA-loaded PLGA microspheres, encapsulation efficiency and cumulative release increased with initial drug loading. Similarly, cumulative release from FA...

  9. Method of detecting luminescent target ions with modified magnetic microspheres

    Science.gov (United States)

    Shkrob, Ilya A; Kaminski, Michael D

    2014-05-13

    This invention provides methods of using modified magnetic microspheres to extract target ions from a sample in order to detect their presence in a microfluidic environment. In one or more embodiments, the microspheres are modified with molecules on the surface that allow the target ions in the sample to form complexes with specific ligand molecules on the microsphere surface. In one or more embodiments, the microspheres are modified with molecules that sequester the target ions from the sample, but specific ligand molecules in solution subsequently re-extract the target ions from the microspheres into the solution, where the complexes form independent of the microsphere surface. Once the complexes form, they are exposed to an excitation wavelength light source suitable for exciting the target ion to emit a luminescent signal pattern. Detection of the luminescent signal pattern allows for determination of the presence of the target ions in the sample.

  10. Albumin microspheres labeled with Ga-67 by chelation: concise communication.

    Science.gov (United States)

    Hnatowich, D J; Schlegel, P

    1981-07-01

    Albumin microspheres have been synthesized eith EDTA and DTPA chelating groups covalently bound to their surface. The microspheres may be labeled with Ga-67 at high yield (97 +/- 2%) by transcomplexation from a 0.1 M Ga-67 acetate solution. With EDTA microspheres the resulting label dissociates only slightly after no detectable dissociation over this period. By contrast, microspheres without chelating groups lose their label virtually completely under these conditions. Following intravenous administration of sized Ga-67 DTPA microspheres in mice, about (84 +/- 16)% of the activity localizes in the lungs at 5 min, with (60 +/- 7)% remaining after 2 hr. Since labeling is by chelation, the microspheres may also be tagged with other metallic radionuclides

  11. Laser-assisted fabrication of highly viscous alginate microsphere

    Science.gov (United States)

    Lin, Yafu; Huang, Yong

    2011-04-01

    Encapsulated microspheres have been widely used in various biomedical applications. However, fabrication of encapsulated microspheres from highly viscous materials has always been a manufacturing challenge. The objective of this study is to explore a novel metallic foil-assisted laser-induced forward transfer (LIFT), a laser-assisted fabrication technique, to make encapsulated microspheres using high sodium alginate concentration solutions. The proposed four-layer approach includes a quartz disk, a sacrificial and adhesive layer, a metallic foil, and a transferred suspension layer. It is found that the proposed four-layer modified LIFT approach provides a promising fabrication technology for making of bead-encapsulated microspheres from highly viscous solutions. During the process, the microsphere only can be formed if the direct-writing height is larger than the critical direct-writing height; otherwise, tail structured droplets are formed; and the encapsulated microsphere diameter linearly increases with the laser fluence and decreases with the sodium alginate concentration.

  12. Formation of core (polystyrene)-shell (polybenzimidazole) nanoparticles using sulfonated polystyrene as template.

    Science.gov (United States)

    Hazarika, Mousumi; Arunbabu, Dhamodaran; Jana, Tushar

    2010-11-15

    We report formation of core (polystyrene)-shell (polybenzimidazole) nanoparticles from a new blend system consisting of an amorphous polymer polybenzimidazole (PBI) and an ionomer sodium salt of sulfonated polystyrene (SPS-Na). The ionomer used for the blending is spherical in shape with sulfonate groups on the surface of the particles. An in depth investigation of the blends at various sulfonation degrees and compositions using Fourier transform infrared (FT-IR) spectroscopy provides direct evidence of specific hydrogen bonding interactions between the N-H groups of PBI and the sulfonate groups of SPS-Na. The disruption of PBI chains self association owing to the interaction between the functional groups of these polymer pairs is the driving force for the blending. Thermodynamical studies carried out by using differential scanning calorimeter (DSC) establish partially miscible phase separated blending of these polymers in a wider composition range. The two distinguishable glass transition temperatures (T(g)) which are different from the neat components and unaltered with the blends composition attribute that the domain size of heterogeneity (d(d)) of the blends is >20 nm since one of the blend component (SPS-Na particle) diameter is ∼70 nm. The diminish of PBI chains self association upon blending with SPS-Na particles and the presence of invariant T(g)'s of the blends suggest the wrapping of PBI chains over the SPS-Na spherical particle surface and hence resulting a core-shell morphology. Transmission electron microscopy (TEM) study provides direct evidence of core-shell nanoparticle formation; where core is the polystyrene and shell is the PBI. The sulfonation degree affects the blends phase separations. The higher degree of sulfonation favors the disruption of PBI self association and thus forms partially miscible two phases blends with core-shell morphology.

  13. Molecularly imprinted microspheres prepared by precipitation polymerization at high monomer concentrations

    Directory of Open Access Journals (Sweden)

    Renkecz Tibor

    2014-01-01

    Full Text Available Highly crosslinked polymer microparticles have been prepared by precipitation polymerization using high monomer loadings (≥25 v/v % which generally would lead to bulk monoliths. The microparticle format was achieved by the use of non-solvating diluents either alone or in combination with co-solvents. Two distinct morphologies were observed. Monodisperse smooth microspheres were obtained using a thermodynamically good co-solvent whereas segmented irregular particles were formed with poorer co-solvents. It has been found that during polymerization the forming polymer particles were enriched in the co-solvent and this effect was more pronounced when good co-solvents were used. The type of functional monomer, crosslinker and co-solvent, and the non-solvent/co-solvent ratio were identified as influential parameters on the microparticle morphology. With the proposed methodology molecularly imprinted microparticles have been prepared successfully for three different templates, naproxen, diclofenac and toltrazuril using various functional monomers, crosslinkers and polymerization solvent mixtures.

  14. Enabling high-rate electrochemical flow capacitors based on mesoporous carbon microspheres suspension electrodes

    Science.gov (United States)

    Tian, Meng; Sun, Yueqing; Zhang, Chuanfang (John); Wang, Jitong; Qiao, Wenming; Ling, Licheng; Long, Donghui

    2017-10-01

    Electrochemical flow capacitor (EFC) is a promising technology for grid energy storage, which combines the fast charging/discharging capability of supercapacitors with the scalable energy capacity of flow batteries. In this study, we report a high-power-density EFC using mesoporous carbon microspheres (MCMs) as suspension electrodes. By using a simple yet effective spray-drying technique, monodispersed MCMs with average particle size of 5 μm, high BET surface area of 1150-1267 m2 g-1, large pore volume of 2-4 cm3 g-1 and controllable mesopore size of 7-30 nm have been successfully prepared. The resultant MCMs suspension electrode shows excellent stability and considerable high capacitance of 100 F g-1 and good cycling ability (86% of initial capacitance after 10000 cycles). Specially, the suspension electrode exhibits excellent rate performance with 75% capacitance retention from 2 to 100 mV s-1, significantly higher than that of microporous carbon electrodes (20∼30%), due to the developed mesoporous channels facilitating for rapid ion diffusion. In addition, the electrochemical responses on both negative and positive suspension electrodes are studied, based on which an optimal capacitance matching between them is suggested for large-scale EFC unit.

  15. A generalized quantitative interpretation of dark-field contrast for highly concentrated microsphere suspensions

    Science.gov (United States)

    Gkoumas, Spyridon; Villanueva-Perez, Pablo; Wang, Zhentian; Romano, Lucia; Abis, Matteo; Stampanoni, Marco

    2016-10-01

    In X-ray grating interferometry, dark-field contrast arises due to partial extinction of the detected interference fringes. This is also called visibility reduction and is attributed to small-angle scattering from unresolved structures in the imaged object. In recent years, analytical quantitative frameworks of dark-field contrast have been developed for highly diluted monodisperse microsphere suspensions with maximum 6% volume fraction. These frameworks assume that scattering particles are separated by large enough distances, which make any interparticle scattering interference negligible. In this paper, we start from the small-angle scattering intensity equation and, by linking Fourier and real-space, we introduce the structure factor and thus extend the analytical and experimental quantitative interpretation of dark-field contrast, for a range of suspensions with volume fractions reaching 40%. The structure factor accounts for interparticle scattering interference. Without introducing any additional fitting parameters, we successfully predict the experimental values measured at the TOMCAT beamline, Swiss Light Source. Finally, we apply this theoretical framework to an experiment probing a range of system correlation lengths by acquiring dark-field images at different energies. This proposed method has the potential to be applied in single-shot-mode using a polychromatic X-ray tube setup and a single-photon-counting energy-resolving detector.

  16. Simplified prototyping of perfusable polystyrene microfluidics

    Science.gov (United States)

    Tran, Reginald; Ahn, Byungwook; R. Myers, David; Qiu, Yongzhi; Sakurai, Yumiko; Moot, Robert; Mihevc, Emma; Trent Spencer, H.; Doering, Christopher; A. Lam, Wilbur

    2014-01-01

    Cell culture in microfluidic systems has primarily been conducted in devices comprised of polydimethylsiloxane (PDMS) or other elastomers. As polystyrene (PS) is the most characterized and commonly used substrate material for cell culture, microfluidic cell culture would ideally be conducted in PS-based microsystems that also enable tight control of perfusion and hydrodynamic conditions, which are especially important for culture of vascular cell types. Here, we report a simple method to prototype perfusable PS microfluidics for endothelial cell culture under flow that can be fabricated using standard lithography and wet laboratory equipment to enable stable perfusion at shear stresses up to 300 dyn/cm2 and pumping pressures up to 26 kPa for at least 100 h. This technique can also be extended to fabricate perfusable hybrid PS-PDMS microfluidics of which one application is for increased efficiency of viral transduction in non-adherent suspension cells by leveraging the high surface area to volume ratio of microfluidics and adhesion molecules that are optimized for PS substrates. These biologically compatible microfluidic devices can be made more accessible to biological-based laboratories through the outsourcing of lithography to various available microfluidic foundries. PMID:25379106

  17. MULTIMODE THEORY OF WHISPERING GALLERY-MODE MICROSPHERE LASER

    Institute of Scientific and Technical Information of China (English)

    CHAI JIN-HUA; LU YI-QUN; LEUNG PUI-TANG

    2000-01-01

    A multimode theory of whispering-gallery-mode microsphere laser is developed based on the linear and nonlinear semiclassical theory of the microsphere laser. The average photon-number of each lasing mode and the pumping level requirement for multimode coexistence are derived. The comparison between the theory and experimental results shows that the theory can be used to treat the practical problems on microsphere laser.

  18. Solvothermal synthesis and characterization of monodisperse superparamagnetic iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shichuan; Zhang, Tonglai; Tang, Runze; Qiu, Hao [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China); Wang, Caiqin [Shandong Special Industry Group Co., Ltd, Shandong 255201 (China); Zhou, Zunning [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China)

    2015-04-01

    A series of magnetic iron oxide nanoparticle clusters with different structure guide agents were synthesized by a modified solvothermal method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analyses (TG), a vibrating sample magnetometer (VSM) and Fourier transform infrared spectroscopy (FTIR). It is found that the superparamagnetic nanoparticles guided by NaCit (sodium citrate) have high saturation magnetization (M{sub s}) of 69.641 emu/g and low retentivity (M{sub r}) of 0.8 emu/g. Guiding to form superparamagnetic clusters with size range of 80–110 nm, the adherent small-molecule citrate groups on the surface prevent the prefabricated ferrite crystals growing further. In contrast, the primary small crystal guided and stabilized by the PVP long-chain molecules assemble freely to larger ones and stop growing in size range of 100–150 nm, which has saturation magnetization (M{sub s}) of 97.979 emu/g and retentivity (M{sub r}) of 46.323 emu/g. The relevant formation mechanisms of the two types of samples are proposed at the end. The superparamagnetic ferrite clusters guided by sodium citrate are expected to be used for movement controlling of passive interference particles to avoid aggregation and the sample guided by PVP will be a candidate of nanometer wave absorbing material. - Highlights: • A facile synthesis of two kinds of monodisperse iron oxide nano-particle clusters was performed via a modified one-step solvothermal method in this work. • The NaCit and PVP as different guiding agents are used to control the formation and aggregation of nano-crystals during reacting and the ripening processes. • The superparamagnetic NaCit–Fe{sub 3}O{sub 4} samples have high saturation magnetization (M{sub s}) of 69.641 emu/g and low retentivity (M{sub r}) of 0.8 emu/g. • The relevant formation mechanisms of the two types of samples are proposed.

  19. Preparation and characterization of immobilized lipase on magnetic hydrophobic microspheres

    DEFF Research Database (Denmark)

    Guo, Zheng; Bai, Shu; Sun, Yan

    2003-01-01

    A novel magnetic poly(vinyl acetate (VAc)–divinyl benzene (DVB)) material (8–34 μm) was synthesized by copolymerization of vinyl acetate and divinyl benzene using oleic acid-stabilized magnetic colloids as magnetic cores. The magnetic colloids and the copolymer microspheres were characterized...... with transmission and scanning electron microscopes, respectively. Magnetization of the microspheres could be described by the Langevin function. All the observations indicated that the microspheres were superparamagnetic. Magnetic sedimentation of the microspheres was achieved within 3 min, over 300 times faster...

  20. Controlled Delivery of Gentamicin Using Poly(3-hydroxybutyrate Microspheres

    Directory of Open Access Journals (Sweden)

    Ipsita Roy

    2011-07-01

    Full Text Available Poly(3-hydroxybutyrate, P(3HB, produced from Bacillus cereus SPV using a simple glucose feeding strategy was used to fabricate P(3HB microspheres using a solid-in-oil-water (s/o/w technique. For this study, several parameters such as polymer concentration, surfactant and stirring rates were varied in order to determine their effect on microsphere characteristics. The average size of the microspheres was in the range of 2 µm to 1.54 µm with specific surface areas varying between 9.60 m2/g and 6.05 m2/g. Low stirring speed of 300 rpm produced slightly larger microspheres when compared to the smaller microspheres produced when the stirring velocity was increased to 800 rpm. The surface morphology of the microspheres after solvent evaporation appeared smooth when observed under SEM. Gentamicin was encapsulated within these P(3HB microspheres and the release kinetics from the microspheres exhibiting the highest encapsulation efficiency, which was 48%, was investigated. The in vitro release of gentamicin was bimodal, an initial burst release was observed followed by a diffusion mediated sustained release. Biodegradable P(3HB microspheres developed in this research has shown high potential to be used in various biomedical applications.

  1. Poly(styrene-acrylic acid) magnetic polymer microspheres

    Institute of Scientific and Technical Information of China (English)

    Yanling CHENG; Liuqiang MA; Ruohui LI

    2008-01-01

    Magnetic polymer microspheres have been considered as a kind of new biopolymer materials with great advantages in bioseparation engineering and biome-dicine engineering because they have not only polymer functional groups but also magnetic characteristics. Styrene-acrylic acid copolymer (p(S-AA)) magnetic microspheres were synthesized by dispersion polymeriza-tion with Fe3O4 as core and p(S-AA) as shell. The micro-spheres were characterized by SEM, size analysis, molecular weight and solid content measurement. All of them indicate that the microspheres are small in size, nar-row in distribution, stable in chemistry and rich in func-tional groups on their surface.

  2. Preparation and Characterization of Albumin Microspheres Encapsulated with Propranolol HCl

    Directory of Open Access Journals (Sweden)

    Sayyed Abolghassem Sajadi Tabassi

    2003-10-01

    Full Text Available Albumin microspheres (AMS have found many applications in the diagnosis and treatment in recent years and more than 100 diagnostic agents and drugs have been incorporated into AMS. In the present study Bovine Serum Albumin (BSA based microspheres bearing propranolol hydrochloride were prepared by an emulsion-internal phase stabilization technique. The prepared microspheres were studied for particle size distribution, drug loading, release characteristics, bioadhesion and in-vitro controlled diffusion across the rat intestine. The microspheres had mean diameters between 1-25 mm of which more than 50 percent were below 5 mm. The encapsulated drug was found to be about 9% w/w of that initially added to microspheres and the superficial drug was 25% of the total amount of the encapsulated drug. Also AMS were noted to possess good bioadhesion in such a way that about 70% of microspheres remained adherent on the surface mucosa of rat jejunum.The drug release from albumin microspheres was mainly controlled by diffusion and showed a biphasic pattern with a high initial release (burst effect, followed by a more gradual terminal release. The total amount of drug released from microspheres after 12h was 70%. In vitro experiments on the rat intestinal segments revealed that the microspheres could effectively pass their content through intestinal membrane.

  3. Chitosan microspheres in PLG films as devices for cytarabine release.

    Science.gov (United States)

    Blanco, M D; Gómez, C; Olmo, R; Muñiz, E; Teijón, J M

    2000-07-20

    Cytarabine was included in chitosan microspheres and several of these microspheres were embedded in a poly(lactide-co-glycolide) (PLG) film to constitute a comatrix system, to develop a prolonged release form. Chitosan microspheres, in the range of 92+/-65 microm, having good spherical geometry and a smooth surface incorporating cytarabine, were prepared. The cytarabine amount included in chitosan microspheres was 43.7 microg of ara-C per milligram microsphere. The incorporation efficiency of the cytarabine in microspheres was 70.6%. Total cytarabine release from microspheres in vitro was detected at 48 h. Inclusion of cytarabine-loaded microspheres in poly(lactide-co-glycolide) film initiated a slower release of the drug and, in this way, the maximum of cytarabine released (80%) took place in vitro at 94.5 h. Comatrices, with 8.7 mg of cytarabine, signifying a dose of 34.5 microg/kg, were subcutaneously implanted in the back of rats. Maximum plasma cytarabine concentration was 18.5+/-1.5 microg/ml, 48 h after the device implantation and the drug was detected in plasma for 13 days. The histological studies show a slow degradative process. After 6 months of implantation, most of the microspheres of the matrix seemed to be intact, the comatrix appeared surrounded by conjunctive tissue and small blood vessels and nerve packets were detected in the periphery of the implant.

  4. 3D investigation on polystyrene colloidal crystals by floatage self-assembly with mixed solvent via synchrotron radiation x-ray phase-contrast computed tomography

    Science.gov (United States)

    Fu, Yanan; Xie, Honglan; Deng, Biao; Du, Guohao; Xiao, Tiqiao

    2017-06-01

    The floatage self-assembly method was introduced with mixed solvent as the medium of polystyrene sphere suspension to fabricate the colloidal crystal. The three dimensional (3D) void system of the colloidal crystal was noninvasively characterized by synchrotron radiation phase-contrast computed tomography, and the quantitative image analysis was implemented aiming to the polystyrene sphere colloidal crystal. Comparing with gravity sedimentation method, the three samples fabricated from floatage self-assembly with mixed solvents have the lowest porosity, and when ethylene glycol and water were mixed with ratio of 1:1, the lowest porosity of 27.49% could be achieved, that has been very close to the minimum porosity of ordered 3D monodisperse sphere array (26%). In single slices, the porosities and fractal dimension for the voids were calculated. The results showed that two factors would significantly influence the porosity of the whole colloidal crystal: the first deposited sphere layer's orderliness and the sedimentation speed of the spheres. The floatage self-assembly could induce a stable close-packing process, resulted from the powerful nucleation force-lateral capillary force coupled with the mixed solvent to regulate the floating upward speed for purpose of matching the assembly rate.

  5. Study on Immunoassay by Fluorescent Microsphere-Based Technology%应用荧光微球技术进行免疫检测研究

    Institute of Scientific and Technical Information of China (English)

    张燕玲; 陈超; 杨慧; 薛小平

    2011-01-01

    Human immunoglobin G(IgG) and swine hemoglobin(Hb) were coupled to the carboxylated polystyrene fluorescent microsphere used as solid carrier,and Luminex-100? System was used to detect the coupling efficiency between fluorescent microsphere and IgG or Hb. Results showed that,the maximal coupling efficiency could be achieved by using 100 jug ? mL-1 antibody or antigen,and the detection was fast and sensitive. It is feasible to apply fluorescent microsphere technology to immunodetection.%以聚苯乙烯羧基荧光微球为固相载体,将人免疫球蛋白G(IgG)和猪血红蛋白(Hb)分别与微球偶联,应用Luminex-100TM荧光微球检测系统检测抗体IgG和抗原Hb与荧光微球的偶联效率.结果表明,采用100μg·mL-1抗体或抗原浓度可以获得较高的偶联效率,且检测快速灵敏.应用荧光微球进行抗原抗体免疫检测可行.

  6. The Effect of Counterions on the Blend Miscibility of Polystyrene with Sulfonated Polystyrene Ionomers

    Science.gov (United States)

    Zhou, Nancy C.; Burghardt, Wesley R.; Composto, Russell J.; Winey, Karen I.

    2006-03-01

    Our previous study probed the miscibility of polystyrene (PS) and sulfonated polystyrene (P(S-SSx)) of differing sulfonation levels (x) and found a narrow window of miscibility. Specifically, the PS:P(S-SSx) blend system becomes completely immiscible at unexpectedly low sulfonation level, x = 2.7 mol% . Here we extend the study of blend miscibility of PS with P(S-SS0.007) to include materials neutralized with sodium, barium and zinc cations. These ionomer blends exhibit an upper critical solution temperature (UCST) behavior with an increase in critical temperature as compared to the blend with unneutralized P(S-SS0.007). Forward recoil spectrometry (FRES) results indicate that Zn^++ and Ba^++ neutralized ionomers are less miscible than Na^+ when fully neutralized, while the blend miscibility for Na^+ and Zn^++ neutralized ionomers behave similarly when partially neutralized. Rheological studies are underway to compliment the blend miscibility studies. These miscibility information gained from PS/P(S-SSx) ionomers blends will serve as a foundation for future ionomer morphology studies.

  7. Non-isothermal crystallization kinetics of syndiotactic polystyrene polystyrene functionalized SWNTs nanocomposites

    Directory of Open Access Journals (Sweden)

    2007-07-01

    Full Text Available Non-isothermal crystallization kinetics were characterized by using differential scanning calorimetry (DSC analysis on neat semicrystalline syndiotactic polystyrene (sPS and its nanocomposites with polystyrene (PS functionalized full-length single walled carbon nanotubes (SWNT-PS, which was prepared by copper (I catalyzed click coupling of alkyne-decorated SWNTs with well-defined, azide-terminated PS. The crystallization behavior of neat sPS polymer was compared to its SWNT based nanocomposites. The results suggested that the non-isothermal crystallization behavior of sPS/SWNT-PS nanocomposites depended significantly on the SWNT-PS content and cooling rate. The incorporation of SWNT-PS caused a change in the mechanism of nucleation and the crystal growth of sPS crystallites, this effect being more significant at lower SWNT-PS content. Combined Avrami and Ozawa analysis was found to be effective in describing the non-isothermal crystallization of the neat sPS and its nanocomposites. The activation energy of sPS determined from non-isothermal data decreased with the presence of small quantity of SWNT-PS in the nanocomposites and then increased with increasing SWNT-PS content.

  8. Monodisperse, submicrometer droplets via condensation of microfluidic-generated gas bubbles.

    Science.gov (United States)

    Seo, Minseok; Matsuura, Naomi

    2012-09-10

    Microfluidics (MFs) can produce monodisperse droplets with precise size control. However, the synthesis of monodisperse droplets much smaller than the minimum feature size of the microfluidic device (MFD) remains challenging, thus limiting the production of submicrometer droplets. To overcome the minimum micrometer-scale droplet sizes that can be generated using typical MFDs, the droplet material is heated above its boiling point (bp), and then MFs is used to produce monodisperse micrometer-scale bubbles (MBs) that are easily formed in the size regime where standard MFDs have excellent size control. After MBs are formed, they are cooled, condensing into dramatically smaller droplets that are beyond the size limit achievable using the original MFD, with a size decrease corresponding to the density difference between the gas and liquid phases of the droplet material. Herein, it is shown experimentally that monodisperse, submicrometer droplets of predictable sizes can be condensed from a monodisperse population of MBs as generated by MFs. Using perfluoropentane (PFP) as a representative solvent due to its low bp (29.2 °C), it is demonstrated that monodisperse PFP MBs can be produced at MFD temperatures >3.6 °C above the bp of PFP over a wide range of sizes (i.e., diameters from 2 to 200 μm). Independent of initial size, the generated MBs shrink rapidly in size from about 3 to 0 °C above the bp of PFP, corresponding to a phase change from gas to liquid, after which they shrink more slowly to form fully condensed droplets with diameters 5.0 ± 0.1 times smaller than the initial size of the MBs, even in the submicrometer size regime. This new method is versatile and flexible, and may be applied to any type of low-bp solvent for the manufacture of different submicrometer droplets for which precisely controlled dimensions are required.

  9. Neutron transmission measurements on hydrogen filled microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Dyrnjaja, Eva, E-mail: dyrnjaja@ati.ac.at [Vienna University of Technology, Institute of Atomic and Subatomic Physics, Stadionallee 2, Vienna (Austria); Hummel, Stefan, E-mail: hummel@fotec.at [FOTEC GmbH, Viktor Kaplan-Straße 2, 2700 Wiener Neustadt (Austria); Keding, Marcus, E-mail: keding@fotec.at [FOTEC GmbH, Viktor Kaplan-Straße 2, 2700 Wiener Neustadt (Austria); Smolle, Marie-Theres, E-mail: marie-theres.smolle@tuwien.ac.at [Vienna University of Technology, Institute of Atomic and Subatomic Physics, Stadionallee 2, Vienna (Austria); Gerger, Joachim, E-mail: gerger@fotec.at [FOTEC GmbH, Viktor Kaplan-Straße 2, 2700 Wiener Neustadt (Austria); Zawisky, Michael, E-mail: zawisky@ati.ac.at [Vienna University of Technology, Institute of Atomic and Subatomic Physics, Stadionallee 2, Vienna (Austria)

    2014-01-01

    Hollow microspheres are promising candidates for future hydrogen storage technologies. Although the physical process for hydrogen diffusion through glass is well understood, measurements of static quantities (e.q. hydrogen pressure inside the spheres) as well as dynamic properties (e.g. diffusion rate of hydrogen through glass) are still difficult to handle due to the small size of the spheres (d≈15μm). For diffusion rate measurements, the long-term stability of the experiment is also mandatory due to the relatively slow diffusion rate. In this work, we present an accurate and long-term stable measurement technique for static and dynamic properties, using neutron radiography. Furthermore, possible applications for hydrogen filled microspheres within the scope of radiation issues are discussed.

  10. Optical Microspherical Resonators for Biomedical Sensing

    Directory of Open Access Journals (Sweden)

    Giancarlo C. Righini

    2011-01-01

    Full Text Available Optical resonators play an ubiquitous role in modern optics. A particular class of optical resonators is constituted by spherical dielectric structures, where optical rays are total internal reflected. Due to minimal reflection losses and to potentially very low material absorption, these guided modes, known as whispering gallery modes, can confer the resonator an exceptionally high quality factor Q, leading to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. These attractive characteristics make these miniaturized optical resonators especially suited as laser cavities and resonant filters, but also as very sensitive sensors. First, a brief analysis is presented of the characteristics of microspherical resonators, of their fabrication methods, and of the light coupling techniques. Then, we attempt to overview some of the recent advances in the development of microspherical biosensors, underlining a number of important applications in the biomedical field.

  11. Aptamer Based Microsphere Biosensor for Thrombin Detection

    Directory of Open Access Journals (Sweden)

    Xudong Fan

    2006-08-01

    Full Text Available We have developed an optical microsphere resonator biosensor using aptamer asreceptor for the measurement of the important biomolecule thrombin. The sphere surface ismodified with anti-thrombin aptamer, which has excellent binding affinity and selectivityfor thrombin. Binding of the thrombin at the sphere surface is monitored by the spectralposition of the microsphere’s whispering gallery mode resonances. A detection limit on theorder of 1 NIH Unit/mL is demonstrated. Control experiments with non-aptameroligonucleotide and BSA are also carried out to confirm the specific binding betweenaptamer and thrombin. We expect that this demonstration will lead to the development ofhighly sensitive biomarker sensors based on aptamer with lower cost and higher throughputthan current technology.

  12. Sputter coating of microspherical substrates by levitation

    Science.gov (United States)

    Lowe, A.T.; Hosford, C.D.

    Microspheres are substantially uniformly coated with metals or nonmetals by simltaneously levitating them and sputter coating them at total chamber pressures less than 1 torr. A collimated hole structure comprising a parallel array of upwardly projecting individual gas outlets is machined out to form a dimple. Glass microballoons,, which are particularly useful in laser fusion applications, can be substantially uniformly coated using the coating method and apparatus.

  13. Quantifying the rate of biofilm growth of S. meliloti strains in microfluidics via the diffusion coefficient of microspheres

    Science.gov (United States)

    Dorian, Matthew; Seitaridou, Effrosyni

    2014-03-01

    Understanding the rate of biofilm growth is essential for studying genes and preventing unwanted biofilms. In this study, the diffusion coefficient (D) of polystyrene microspheres was used to quantify biofilm growth rates of Sinorhizobia meliloti, a nitrogen fixing bacteria that forms a symbiotic relationship with alfalfa plants. Five strains were studied, two wild types (8530 expR+ and 1021) and three mutants in the exopolysaccharide (EPS I, EPS II) synthesis (8530 exoY , 9034 expG , and 9030-2 expA 1); 1021 and 9030-2 expA 1 are known to be unable to form biofilms. Each strain was inserted into a microfluidic channel with the microspheres. As the cultures grew, the spheres' D values were obtained every 24 hours for 4 days using fluorescence microscopy. Although the D values for 9030-2 expA 1 were inconclusive, 8530 expR+ , 8530 exoY , and 9034 expG showed significant decreases in D between 3 days of growth (| z | > 2 . 25 , p 0 . 05), which shows the lack of a structured biofilm community. Thus, D can be used as an indicator of the presence of a biofilm and its development.

  14. STUDY ON LIGHTLY SULFONATED SYNDIOTACTIC POLYSTYRENE IONOMERS

    Institute of Scientific and Technical Information of China (English)

    Jin Wang; Fang-ming Zhu; Jin-cheng Lui; Hua-ming Li; Shang-an Lin

    2001-01-01

    ulfonated syndiotactic polystyrene ionomers (SsPS) with 1.8 mol% degree of sulfonation have been studied.SWAXD shows that the crystallinity of SsPS ionomers was decreased with increasing diameter size of the counter ions and sPS > SsPS-H > SsPS-K > SsPS-Zn. Moreover, SsPS ionomers only have α crystal form, while original sPS has two crystal forms: α and β crystal form. TGA shows that the thermal stability of SsPS ionomers is higher than that of the original sPS and SsPS-Zn > SsPS-K > SsPS-H. DSC shows that all the glass transition temperatures (Tg) of SsPS ionomers are higher than that of the neat sPS and SsPS-Zn > SsPS-Na > SsPS-K > SsPS-H. However, the melting temperature (Tm) and crystallization peak temperature (Tp) of SsPS ionomers are lower and SsPS-H > SsPS-Zn > SsPS-K > SsPS-Na, while the crystallinity (Xc) of SsPS-Zn is the lowest. Nonisothermal crystallization kinetics shows that the Avrami index of sPS and SsPS-H are both about 4, suggesting the nucleation growth of SsPS-H with lower degree of sulfonation still keeps its threedimension form. FTIR spectra of SsPS ionomers show a splitting absorption band for asymmetric stretching vibration of sulfonation group. The CH in-plane bending vibration of benzene ring shifted to higher wavenumber and the symmetric stretching vibration of sulfonation group changed slightly with different counter ion neutralized SsPS ionomers.

  15. Benchtop micromolding of polystyrene by soft lithography.

    Science.gov (United States)

    Wang, Yuli; Balowski, Joseph; Phillips, Colleen; Phillips, Ryan; Sims, Christopher E; Allbritton, Nancy L

    2011-09-21

    Polystyrene (PS), a standard material for cell culture consumable labware, was molded into microstructures with high fidelity of replication by an elastomeric polydimethylsiloxane (PDMS) mold. The process was a simple, benchtop method based on soft lithography using readily available materials. The key to successful replica molding by this simple procedure relies on the use of a solvent, for example, gamma-butyrolactone, which dissolves PS without swelling the PDMS mold. PS solution was added to the PDMS mold, and evaporation of the solvent was accomplished by baking the mold on a hotplate. Microstructures with feature sizes as small as 3 μm and aspect ratios as large as 7 were readily molded. Prototypes of microfluidic chips made from PS were prepared by thermal bonding of a microchannel molded in PS with a flat PS substrate. The PS microfluidic chip displayed much lower adsorption and absorption of hydrophobic molecules (e.g. rhodamine B) compared to a comparable chip created from PDMS. The molded PS surface exhibited stable surface properties after plasma oxidation as assessed by contact angle measurement. The molded, oxidized PS surface remained an excellent surface for cell culture based on cell adhesion and proliferation. To demonstrate the application of this process for cell biology research, PS was micromolded into two different microarray formats, microwells and microposts, for segregation and tracking of non-adherent and adherent cells, respectively. The micromolded PS possessed properties that were ideal for biological and bioanalytical needs, thus making it an alternative material to PDMS and suitable for building lab-on-a-chip devices by soft lithography methods. This journal is © The Royal Society of Chemistry 2011

  16. Polystyrene nanoparticles affect Xenopus laevis development

    Energy Technology Data Exchange (ETDEWEB)

    Tussellino, Margherita; Ronca, Raffaele [University of Naples Federico II, Department of Biology (Italy); Formiggini, Fabio [Italian Institute of Technology, Center for Advanced Biomaterials for Health Care IIT@CRIB (Italy); Marco, Nadia De [University of Naples Federico II, Department of Biology (Italy); Fusco, Sabato; Netti, Paolo Antonio [Italian Institute of Technology, Center for Advanced Biomaterials for Health Care IIT@CRIB (Italy); Carotenuto, Rosa, E-mail: rosa.carotenuto@unina.it [University of Naples Federico II, Department of Biology (Italy)

    2015-02-15

    Exposing living organisms to nanoparticulates is potentially hazardous, in particular when it takes place during embryogenesis. In this investigation, we have studied the effects of 50-nm-uncoated polystyrene nanoparticles (PSNPs) as a model to investigate the suitability of their possible future employments. We have used the standardized Frog Embryo Teratogenesis Assay-Xenopus test during the early stages of larval development of Xenopus laevis, and we have employed either contact exposure or microinjections. We found that the embryos mortality rate is dose dependent and that the survived embryos showed high percentage of malformations. They display disorders in pigmentation distribution, malformations of the head, gut and tail, edema in the anterior ventral region, and a shorter body length compared with sibling untreated embryos. Moreover, these embryos grow more slowly than the untreated embryos. Expressions of the mesoderm markers, bra (T-box Brachyury gene), myod1 (myogenic differentiation1), and of neural crest marker sox9 (sex SRY (determining region Y-box 9) transcription factor sox9), are modified. Confocal microscopy showed that the nanoparticles are localized in the cytoplasm, in the nucleus, and in the periphery of the digestive gut cells. Our data suggest that PSNPs are toxic and show a potential teratogenic effect for Xenopus larvae. We hypothesize that these effects may be due either to the amount of NPs that penetrate into the cells and/or to the “corona” effect caused by the interaction of PSNPs with cytoplasm components. The three endpoints of our study, i.e., mortality, malformations, and growth inhibition, suggest that the tests we used may be a powerful and flexible bioassay in evaluating pollutants in aquatic embryos.

  17. Polystyrene nanoparticles affect Xenopus laevis development

    Science.gov (United States)

    Tussellino, Margherita; Ronca, Raffaele; Formiggini, Fabio; Marco, Nadia De; Fusco, Sabato; Netti, Paolo Antonio; Carotenuto, Rosa

    2015-02-01

    Exposing living organisms to nanoparticulates is potentially hazardous, in particular when it takes place during embryogenesis. In this investigation, we have studied the effects of 50-nm-uncoated polystyrene nanoparticles (PSNPs) as a model to investigate the suitability of their possible future employments. We have used the standardized Frog Embryo Teratogenesis Assay- Xenopus test during the early stages of larval development of Xenopus laevis, and we have employed either contact exposure or microinjections. We found that the embryos mortality rate is dose dependent and that the survived embryos showed high percentage of malformations. They display disorders in pigmentation distribution, malformations of the head, gut and tail, edema in the anterior ventral region, and a shorter body length compared with sibling untreated embryos. Moreover, these embryos grow more slowly than the untreated embryos. Expressions of the mesoderm markers, bra (T-box Brachyury gene), myod1 (myogenic differentiation1), and of neural crest marker sox9 (sex SRY (determining region Y-box 9) transcription factor sox9), are modified. Confocal microscopy showed that the nanoparticles are localized in the cytoplasm, in the nucleus, and in the periphery of the digestive gut cells. Our data suggest that PSNPs are toxic and show a potential teratogenic effect for Xenopus larvae. We hypothesize that these effects may be due either to the amount of NPs that penetrate into the cells and/or to the "corona" effect caused by the interaction of PSNPs with cytoplasm components. The three endpoints of our study, i.e., mortality, malformations, and growth inhibition, suggest that the tests we used may be a powerful and flexible bioassay in evaluating pollutants in aquatic embryos.

  18. Yttrium-90 microsphere induced gastrointestinal tract ulceration

    Directory of Open Access Journals (Sweden)

    Rikabi Ali A

    2008-09-01

    Full Text Available Abstract Background Radiomicrosphere therapy (RT utilizing yttrium-90 (90Y microspheres has been shown to be an effective regional treatment for primary and secondary hepatic malignancies. We sought to determine a large academic institution's experience regarding the extent and frequency of gastrointestinal complications. Methods Between 2004 and 2007, 27 patients underwent RT for primary or secondary hepatic malignancies. Charts were subsequently reviewed to determine the incidence and severity of GI ulceration. Results Three patients presented with gastrointestinal bleeding and underwent upper endoscopy. Review of the pretreatment angiograms showed normal vascular anatomy in one patient, sclerosed hepatic vasculature in a patient who had undergone prior chemoembolization in a second, and an aberrant left hepatic artery in a third. None had undergone prophylactic gastroduodenal artery embolization. Endoscopic findings included erythema, mucosal erosions, and large gastric ulcers. Microspheres were visible on endoscopic biopsy. In two patients, gastric ulcers were persistent at the time of repeat endoscopy 1–4 months later despite proton pump inhibitor therapy. One elderly patient who refused surgical intervention died from recurrent hemorrhage. Conclusion Gastrointestinal ulceration is a known yet rarely reported complication of 90Y microsphere embolization with potentially life-threatening consequences. Once diagnosed, refractory ulcers should be considered for aggressive surgical management.

  19. Unstirred Water Layer Effects on Biodegradable Microspheres

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    Susan D’Souza

    2015-01-01

    Full Text Available This study explores the mechanistic aspects of in vitro release from biodegradable microspheres with the objective of understanding the effect of the unstirred water layer on polymer degradation and drug release. In vitro drug release experiments on Leuprolide PLGA microspheres were performed under “static” and “continuous” agitation conditions using the “sample and separate” method. At specified time intervals, polymer degradation, mass loss, and drug release were assessed. While molecular weight and molecular number profiles for “static” and “continuous” samples were indistinct, mass loss occurred at a faster rate in “continuous” samples than under “static” conditions. In vitro results describe a fourfold difference in drug release rates between the “continuous” and “static” samples, ascribed to the acceleration of various processes governing release, including elimination of the boundary layer. The findings were confirmed by the fourfold increase in drug release rate when “static” samples were subjected to “continuous” agitation after 11 days. A schema was proposed to describe the complex in vitro release process from biodegradable polymer-drug dosage forms. These experiments highlight the manner in which the unstirred water layer influences drug release from biodegradable microspheres and stress the importance of selecting appropriate conditions for agitation during an in vitro release study.

  20. STUDIES AND EVALUATION OF COMPRESSED MICROSPHERES

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    Idris Mohamed El-Mahdi

    2016-05-01

    Full Text Available This work was aimed at the use of dissolution testing and similarity factor to assess the level of damage taken by active drug microspheres during compression in tablet dosage form. To achieve that, combinations of suitable excipients were used to protect drug microspheres during compression. The excipients were used in the form of powders, granules or placebo pellets prepared by extrusion-spheronization technology. The excipients were evaluated alone, in combinations and post-compression into compacts.  Preliminary experiments included density, hardness, friability and disintegration on all of the selected excipients. Based on such experiments it was found that the flowability of combination powders was more acceptable than individual excipients. Two combinations of microcrystalline -starch and microcrystalline cellulose -calcium carbonate granules were selected to be compressed with active ketoprofen pellets. In all the combinations used there was a significant amount of damage to drug pellets.  The kinetics of drug release appears to follow the zero-order rate and the rate remained unchanged even when a significant degree of damage to pellets occur. It was found that a high level of excipients is required in order to prepare microspheres as a rapid disintegrating tablet. Citation DOI: 10.21502/limuj.002.01.2016  LIMUJ is licensed under a Creative Commons Attribution 4.0 International License