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Sample records for azlactone-containing polymers combining

  1. Comprehensive theory for star-like polymer micelles: combining classical nucleation and polymer brush theory

    NARCIS (Netherlands)

    Sprakel, J.H.B.; Leermakers, F.A.M.; Cohen Stuart, M.A.; Besseling, N.A.M.

    2008-01-01

    A comprehensive theory is proposed that combines classical nucleation and polymer brush theory to describe star-like polymer micelles. With a minimum of adjustable parameters, the model predicts properties such as critical micelle concentrations and micellar size distributions. The validity of the

  2. Flexible autonomous scavengers: the combination of dielectric polymers and electrets

    Science.gov (United States)

    Jean-Mistral, C.; Vu Cong, T.; Sylvestre, A.

    2012-04-01

    Thanks to their high energy density and their flexibility, scavenging energy with dielectric polymer is a promising alternative to ensure the autonomy of various sensors such as in e-textiles or biomedical applications. Nevertheless, they are passive materials requiring a high bias voltage source to polarize them. Thus, we present here a new design of scavenger using polymer electrets for poling the dielectric polymer. Our scavenger is composed of commercial dielectric polymer (3M VHB 4910) with Teflon electrets developing a potential of -300V, and patterned grease electrodes. The transducer works in a pure shear mode with a maximal strain of 50% at 1Hz. The typical "3D-textured" structure of the scavenger allows the electrets to follow the movement of the dielectric. A complete electromechanical analytical model has been developed thank to the combination of electrets theory and dielectric modelling. Our new autonomous structure, on an optimal resistance, can produce about 0.637mJ.g-1.

  3. Targeting angiogenesis-dependent calcified neoplasms using combined polymer therapeutics.

    Directory of Open Access Journals (Sweden)

    Ehud Segal

    Full Text Available There is an immense clinical need for novel therapeutics for the treatment of angiogenesis-dependent calcified neoplasms such as osteosarcomas and bone metastases. We developed a new therapeutic strategy to target bone metastases and calcified neoplasms using combined polymer-bound angiogenesis inhibitors. Using an advanced "living polymerization" technique, the reversible addition-fragmentation chain transfer (RAFT, we conjugated the aminobisphosphonate alendronate (ALN, and the potent anti-angiogenic agent TNP-470 with N-(2-hydroxypropylmethacrylamide (HPMA copolymer through a Glycine-Glycine-Proline-Norleucine linker, cleaved by cathepsin K, a cysteine protease overexpressed at resorption sites in bone tissues. In this approach, dual targeting is achieved. Passive accumulation is possible due to the increase in molecular weight following polymer conjugation of the drugs, thus extravasating from the tumor leaky vessels and not from normal healthy vessels. Active targeting to the calcified tissues is achieved by ALN's affinity to bone mineral.The anti-angiogenic and antitumor potency of HPMA copolymer-ALN-TNP-470 conjugate was evaluated both in vitro and in vivo. We show that free and conjugated ALN-TNP-470 have synergistic anti-angiogenic and antitumor activity by inhibiting proliferation, migration and capillary-like tube formation of endothelial and human osteosarcoma cells in vitro. Evaluation of anti-angiogenic, antitumor activity and body distribution of HPMA copolymer-ALN-TNP-470 conjugate was performed on severe combined immunodeficiency (SCID male mice inoculated with mCherry-labeled MG-63-Ras human osteosarcoma and by modified Miles permeability assay. Our targeted bi-specific conjugate reduced VEGF-induced vascular hyperpermeability by 92% and remarkably inhibited osteosarcoma growth in mice by 96%.This is the first report to describe a new concept of a narrowly-dispersed combined polymer therapeutic designed to target both tumor and

  4. Conductive Polymer Combined Silk Fiber Bundle for Bioelectrical Signal Recording

    Science.gov (United States)

    Tsukada, Shingo; Nakashima, Hiroshi; Torimitsu, Keiichi

    2012-01-01

    Electrode materials for recording biomedical signals, such as electrocardiography (ECG), electroencephalography (EEG) and evoked potentials data, are expected to be soft, hydrophilic and electroconductive to minimize the stress imposed on living tissue, especially during long-term monitoring. We have developed and characterized string-shaped electrodes made from conductive polymer with silk fiber bundles (thread), which offer a new biocompatible stress free interface with living tissue in both wet and dry conditions. An electroconductive polyelectrolyte, poly(3,4-ethylenedioxythiophene) -poly(styrenesulfonate) (PEDOT-PSS) was electrochemically combined with silk thread made from natural Bombyx mori. The polymer composite 280 µm thread exhibited a conductivity of 0.00117 S/cm (which corresponds to a DC resistance of 2.62 Mohm/cm). The addition of glycerol to the PEDOT-PSS silk thread improved the conductivity to 0.102 S/cm (20.6 kohm/cm). The wettability of PEDOT-PSS was controlled with glycerol, which improved its durability in water and washing cycles. The glycerol treated PEDOT-PSS silk thread showed a tensile strength of 1000 cN in both wet and dry states. Without using any electrolytes, pastes or solutions, the thread directly collects electrical signals from living tissue and transmits them through metal cables. ECG, EEG, and sensory evoked potential (SEP) signals were recorded from experimental animals by using this thread placed on the skin. PEDOT-PSS silk glycerol composite thread offers a new class of biocompatible electrodes in the field of biomedical and health promotion that does not induce stress in the subjects. PMID:22493670

  5. Conductive polymer combined silk fiber bundle for bioelectrical signal recording.

    Directory of Open Access Journals (Sweden)

    Shingo Tsukada

    Full Text Available Electrode materials for recording biomedical signals, such as electrocardiography (ECG, electroencephalography (EEG and evoked potentials data, are expected to be soft, hydrophilic and electroconductive to minimize the stress imposed on living tissue, especially during long-term monitoring. We have developed and characterized string-shaped electrodes made from conductive polymer with silk fiber bundles (thread, which offer a new biocompatible stress free interface with living tissue in both wet and dry conditions.An electroconductive polyelectrolyte, poly(3,4-ethylenedioxythiophene-poly(styrenesulfonate (PEDOT-PSS was electrochemically combined with silk thread made from natural Bombyx mori. The polymer composite 280 µm thread exhibited a conductivity of 0.00117 S/cm (which corresponds to a DC resistance of 2.62 Mohm/cm. The addition of glycerol to the PEDOT-PSS silk thread improved the conductivity to 0.102 S/cm (20.6 kohm/cm. The wettability of PEDOT-PSS was controlled with glycerol, which improved its durability in water and washing cycles. The glycerol treated PEDOT-PSS silk thread showed a tensile strength of 1000 cN in both wet and dry states. Without using any electrolytes, pastes or solutions, the thread directly collects electrical signals from living tissue and transmits them through metal cables. ECG, EEG, and sensory evoked potential (SEP signals were recorded from experimental animals by using this thread placed on the skin. PEDOT-PSS silk glycerol composite thread offers a new class of biocompatible electrodes in the field of biomedical and health promotion that does not induce stress in the subjects.

  6. Study of wood polymer combinations from woods of Kashmir

    International Nuclear Information System (INIS)

    Garg, V.P.; Hari Mohan; Rao, K.N.

    1983-01-01

    This report describes the studies conducted to upgrade inferior woods of Kashmir by the application of radiation polymerization process. The process has brought about improvements in the physical and mechanical properties of wood. Wood polymer composite samples have been studied for their use in flooring, wall panelling, roofing shingles, wood carving and in other decorative items. It has been shown that 10% ethyl silicate, when present along with methyl methacrylate or styrene, considerably improves the impact strength and such wood polymer composite samples do not crack even on nailing. Wood polymer composites have been tested for carving and it has been shown that with 50% polymer content, carving quality is preserved. It has also been shown that surface coated wood is more advantageous for use in roofing shingles. (author)

  7. Dissolution Performance of High Drug Loading Celecoxib Amorphous Solid Dispersions Formulated with Polymer Combinations.

    Science.gov (United States)

    Xie, Tian; Taylor, Lynne S

    2016-03-01

    The aims of this study were twofold. First, to evaluate the effectiveness of selected polymers in inhibiting solution crystallization of celecoxib. Second, to compare the release rate and crystallization tendency of celecoxib amorphous solid dispersions (ASDs) formulated with a single polymer, or binary polymer combinations. The effectiveness of polymers, polyvinylpyrrolidone (PVP), hydroxypropylmethyl cellulose (HPMC) or HPMC acetate succinate (HPMCAS), in maintaining supersaturation of celecoxib solutions was evaluated by performing nucleation induction time measurements. Crystallization kinetics of ASD suspensions were monitored using Raman spectroscopy. Dissolution experiments were carried out under non-sink conditions. Pure amorphous celecoxib crystallized rapidly through both matrix and solution pathways. Matrix and solution crystallization was inhibited when celecoxib was molecularly mixed with a polymer, resulting in release of the drug to form supersaturated solutions. Cellulosic polymers were more effective than PVP in maintaining supersaturation. Combining a cellulosic polymer and PVP enabled improved drug release and stability to crystallization. Inclusion of an effective solution crystallization inhibitor as a minor component in ternary dispersions resulted in prolonged supersaturation following dissolution. This study shows the feasibility of formulation strategies for ASDs where a major polymer component is used to achieve one key property e.g. release, while a minor polymer component is added to prevent crystallization.

  8. Combining living anionic polymerization with branching reactions in an iterative fashion to design branched polymers.

    Science.gov (United States)

    Higashihara, Tomoya; Sugiyama, Kenji; Yoo, Hee-Soo; Hayashi, Mayumi; Hirao, Akira

    2010-06-16

    This paper reviews the precise synthesis of many-armed and multi-compositional star-branched polymers, exact graft (co)polymers, and structurally well-defined dendrimer-like star-branched polymers, which are synthetically difficult, by a commonly-featured iterative methodology combining living anionic polymerization with branched reactions to design branched polymers. The methodology basically involves only two synthetic steps; (a) preparation of a polymeric building block corresponding to each branched polymer and (b) connection of the resulting building unit to another unit. The synthetic steps were repeated in a stepwise fashion several times to successively synthesize a series of well-defined target branched polymers. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Color combination of conductive polymers for black electrochromism.

    Science.gov (United States)

    Shin, Haijin; Kim, Yuna; Bhuvana, Thiruvelu; Lee, Jiyea; Yang, Xu; Park, Cheolmin; Kim, Eunkyoung

    2012-01-01

    Conducting polymers that absorb three primary colors, red, green, and blue (RGB), were introduced with a yellow electrochromic polymer (Y) for the preparation of black electrochromic devices. Red poly(3-hexylthiophene) (P3HT) and blue poly(3,4-ethylenedioxythiophene) (PEDOT) were coated on one side of the electrode as a cathodically coloring electrochromic (EC) layer, while green poly(aniline-N-butylsulfonate) (PANBS) and yellow EC poly{[1,3-bis(9',9'-dihexylfluoren-20-yl)azulenyl]-alt-[2",7"-(9",9"-dihexylfluorenyl]} (PDHFA) were coated on the opposite electrode to complete a complementary EC device. The yellow PDHFA layer effectively compensated for absorption below 450 nm and above the 600 nm region, which was lacking in the RGB electrode. The resultant RGBY ECD provided a black color near the CIE black with L*, a*, and b* values of 32, -1.1, and 3.7, respectively, covering a broad absorption in the visible range in the colored state. The state of the black EC device was maintained, even after the electricity was turned off for 200 h, showing stable memory effect. © 2011 American Chemical Society

  10. Entangled Polymer Melts in Extensional Flow - Characterization by Combined Rheology and Small-Angle Neutron Scattering

    DEFF Research Database (Denmark)

    Mortensen, Kell; Kirkensgaard, Jacob JK; Hassager, Ole

    generic knowledge about the process in which macromolecular fluidfilaments are extended and stretched and show how the extensional properties are related to theproperties on individual molecules. We combine structural and rheological studies of a series ofmodel polymers with different composition...... and architectures. The project entails synthesizingmodel polymer systems of precisely known molecular architecture, subjecting these materials tocontrolled extensional flows and to measure the molecular deformation under controlled flowsituation by SANS. Neutron contrast is obtained using specific deuterium labeled...

  11. Free energy and scalings for polymer translocation through a nanopore: A molecular dynamics simulation study combined with milestoning

    International Nuclear Information System (INIS)

    Xue, Xiang-Gui; Zhao, Li; Lu, Zhong-Yuan; Li, Ze-Sheng

    2012-01-01

    Coarse-grained molecular dynamics simulations combined with milestoning method are used to study the stochastic process of polymer chain translocation though a nanopore. We find that the scalings for polymer translocation process (the chain is initialized with the first monomer in the nanopore) and for polymer escape process (the chain is initialized with the middle monomer in the nanopore) are different. The translocation process is mainly controlled by the entropic barrier, while the polymer escape process is driven by the effective force due to free energy difference. -- Highlights: ► We study polymer translocating through a nanopore by CGMD combined with milestoning. ► We find that the scalings for polymer translocation and for polymer escape are different. ► The translocation process is mainly controlled by the entropic barrier. ► The polymer escape process is driven by the effective force due to free energy difference.

  12. Pulmonary surfactant proteins and polymer combinations reduce surfactant inhibition by serum

    Science.gov (United States)

    Lu, Karen W.; Pérez-Gil, Jesús; Echaide, Mercedes; Taeusch, H. William

    2011-01-01

    Acute respiratory distress syndrome (ARDS) is an inflammatory condition that can be associated with capillary leak of serum into alveoli causing inactivation of surfactant. Resistance to inactivation is affected by types and concentrations of surfactant proteins, lipids, and polymers. Our aim was to investigate the effects of different combinations of these three components. A simple lipid mixture (DPPC/POPG) or a more complex lipid mixture (DPPC/POPC/POPG/cholesterol) was used. Native surfactant proteins SP-B and SP-C obtained from pig lung lavage were added either singly or combined at two concentrations. Also, non-ionic polymers polyethylene glycol and dextran and the anionic polymer hyaluronan were added either singly or in pairs with hyaluronan included. Non-ionic polymers work by different mechanisms than anionic polymers, thus the purpose of placing them together in the same surfactant mixture was to evaluate if the combination would show enhanced beneficial effects. The resulting surfactant mixtures were studied in the presence or absence of serum. A modified bubble surfactometer was used to evaluate surface activities. Mixtures that included both SP-B and SP-C plus hyaluronan and either dextran or polyethylene glycol were found to be the most resistant to inhibition by serum. These mixtures, as well as some with either SP-B or SP-C with combined polymers were as or more resistant to inactivation than native surfactant. These results suggest that improved formulations of lung surfactants are possible and may be useful in reducing some types of surfactant inactivation in treating lung injuries. PMID:21741354

  13. Optimized polymer flooding projects via combination of experimental design and reservoir simulation

    Directory of Open Access Journals (Sweden)

    Ali Bengar

    2017-12-01

    Full Text Available The conventional approach for an EOR process is to compare the reservoir properties with those of successful worldwide projects. However, some proper cases may be neglected due to the lack of reliable data. A combination of experimental design and reservoir simulation is an alternative approach. In this work, the fractional factorial design suggests some numerical experiments which their results are analyzed by statistical inference. After determination of the main effects and interactions, the most important parameters of polymer flooding are studied by ANOVA method and Pareto and Tornado charts. Analysis of main effects shows that the oil viscosity, connate water saturation and the horizontal permeability are the 3 deciding factors in oil production. The proposed methodology can help to select the good candidate reservoirs for polymer flooding. Keywords: Polymer flooding, Fractional factorial design, Reservoir simulation, P-value, ANOVA

  14. Electrochemistry, polymers and opto-electronic devices: a combination with a future

    Directory of Open Access Journals (Sweden)

    De Paoli Marco-A.

    2002-01-01

    Full Text Available Electrochemistry came into life with the invention of the pile, by Volta in 1800. He combined different metal discs with a piece of tissue, swollen with an aqueous salt solution. The so-called Pila di Volta used a polymer for the first time in an electrochemical device and can be seen as a powerful idea to create new devices. Recently, polymers became an alternative to make thin and flexible devices. Thus, we find transparent plastic electrodes based on poly(ethylene terephtalate coated with a transition metal oxide. There are also polymer electrolytes based on complexes of inorganic salts and poly(ethylene oxide derivatives, with reasonable ionic conductivity in the absence of solvents. Finally, the electroactive polymers are efficient substitutes for the inorganic semiconductors because they can be synthetically tailored to produce the desired electronic answer. Combining these materials it is possible to assemble different types of electro-optical devices, like electrochromic, photoelectrochemical and light-emitting electrochemical cells.

  15. COMBINED MICROBIAL SURFACTANT-POLYMER SYSTEM FOR IMPROVED OIL MOBILITY AND CONFORMANCE CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Jorge Gabitto; Maria Barrufet

    2004-08-01

    Many domestic oil fields are facing abandonment even though they still contain two-thirds of their original oil. A significant number of these fields can yield additional oil using advanced oil recovery (AOR) technologies. To maintain domestic oil production at current levels, AOR technologies are needed that are affordable and can be implemented by independent oil producers of the future. Microbial enhanced oil recovery (MEOR) technologies have become established as cost-effective solutions for declining oil production. MEOR technologies are affordable for independent producers operating stripper wells and can be used to extend the life of marginal fields. The demonstrated versatility of microorganisms can be used to design advanced microbial systems to treat multiple production problems in complex, heterogeneous reservoirs. The proposed research presents the concept of a combined microbial surfactant-polymer system for advanced oil recovery. The surfactant-polymer system utilizes bacteria that are capable of both biosurfactant production and metabolically-controlled biopolymer production. This novel technology combines complementary mechanisms to extend the life of marginal fields and is applicable to a large number of domestic reservoirs. The research project described in this report is performed jointly by, Bio-Engineering Inc., a woman owned small business, Texas A&M University and Prairie View A&M University, a Historically Black College and University. This report describes the results of our laboratory work to grow microbial cultures and the work done on recovery experiments on core rocks. We have selected two bacterial strains capable of producing both surfactant and polymers. We have conducted laboratory experiments to determine under what conditions surfactants and polymers can be produced from one single strain. We have conduct recovery experiments to determine the performance of these strains under different conditions. Our results do not show a

  16. Amorphous stabilization and dissolution enhancement of amorphous ternary solid dispersions: combination of polymers showing drug-polymer interaction for synergistic effects.

    Science.gov (United States)

    Prasad, Dev; Chauhan, Harsh; Atef, Eman

    2014-11-01

    The purpose of this study was to understand the combined effect of two polymers showing drug-polymer interactions on amorphous stabilization and dissolution enhancement of indomethacin (IND) in amorphous ternary solid dispersions. The mechanism responsible for the enhanced stability and dissolution of IND in amorphous ternary systems was studied by exploring the miscibility and intermolecular interactions between IND and polymers through thermal and spectroscopic analysis. Eudragit E100 and PVP K90 at low concentrations (2.5%-40%, w/w) were used to prepare amorphous binary and ternary solid dispersions by solvent evaporation. Stability results showed that amorphous ternary solid dispersions have better stability compared with amorphous binary solid dispersions. The dissolution of IND from the ternary dispersion was substantially higher than the binary dispersions as well as amorphous drug. Melting point depression of physical mixtures reveals that the drug was miscible in both the polymers; however, greater miscibility was observed in ternary physical mixtures. The IR analysis confirmed intermolecular interactions between IND and individual polymers. These interactions were found to be intact in ternary systems. These results suggest that the combination of two polymers showing drug-polymer interaction offers synergistic enhancement in amorphous stability and dissolution in ternary solid dispersions. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  17. Component dynamics in polymer blends a combined QENS and dielectric spectroscopy investigation

    CERN Document Server

    Hofmann, S; Arbe, A; Colmenero, J; Faragó, B

    2002-01-01

    The individual dynamics of the two constituents of a binary polymer blend was studied by means of quasielastic neutron scattering and dielectric spectroscopy (DS). The combination of neutron spin-echo and backscattering techniques allowed us to cover the complete crossover from entropy-driven chain dynamics on mesoscopic scales to the alpha relaxation on local length scales. The observed blending effects on the respective relaxation times suggest a purely dynamic origin of the dynamic heterogeneity in polymer blends at temperatures well above the glass-transition temperature without the need to assume local phase separation. In contrast, the results from DS experiments towards much lower temperatures indicate systematic deviations of the segmental dynamics in the blend from its mean-field-like behavior at high temperatures. This additionally increases the dynamic heterogeneity in the segmental dynamics of the two components in the mixture. In the case of the chain dynamics, no similar effect could be observed...

  18. COMBINED MICROBIAL SURFACTANT-POLYMER SYSTEM FOR IMPROVED OIL MOBILITY AND CONFORMANCE CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Jorge Gabitto; Maria Barrufet

    2005-08-01

    Many domestic oil fields are facing abandonment even though they still contain two-thirds of their original oil. A significant number of these fields can yield additional oil using advanced oil recovery (AOR) technologies. To maintain domestic oil production at current levels, AOR technologies are needed that are affordable and can be implemented by the independent oil producers of the future. Microbial enhanced oil recovery (MEOR) technologies have become established as cost-effective solutions for declining oil production. MEOR technologies are affordable for independent producers operating stripper wells and can be used to extend the life of marginal fields. The demonstrated versatility of microorganisms can be used to design advanced microbial systems to treat multiple production problems in complex, heterogeneous reservoirs. The proposed research presents the concept of a combined microbial surfactant-polymer system for advanced oil recovery. The surfactant-polymer system utilizes bacteria that are capable of both biosurfactant production and metabolically-controlled biopolymer production. This novel technology combines complementary mechanisms to extend the life of marginal fields and is applicable to a large number of domestic reservoirs. The research project described in this report was performed by Bio-Engineering Inc., a woman owned small business, Texas A&M University and Prairie View A&M University, a Historically Black College and University. This report describes the results of our laboratory work to grow microbial cultures, the work done on recovery experiments on core rocks, and computer simulations. We have selected two bacterial strains capable of producing both surfactant and polymers. We have conducted laboratory experiments to determine under what conditions surfactants and polymers can be produced from one single strain. We have conduct recovery experiments to determine the performance of these strains under different conditions. Our results

  19. Co-delivery of daunomycin and oxaliplatin by biodegradable polymers for safer and more efficacious combination therapy.

    Science.gov (United States)

    Xiao, Haihua; Li, Wenliang; Qi, Ruogu; Yan, Lesan; Wang, Rui; Liu, Shi; Zheng, Yonghui; Xie, Zhigang; Huang, Yubin; Jing, Xiabin

    2012-11-10

    An oxaliplatin pro-drug (Oxa(IV)-COOH) with an axial carboxyl group was synthesized and conjugated to biodegradable polymers with pendant hydroxyl groups to prepare polymer-Oxa(IV) conjugates. A hydrophobic anthracycline-based drug, daunorubicin (DRB) was conjugated to similar biodegradable polymers with carboxyl groups to synthesize polymer-DRB conjugates. The two drug conjugates have the similar polymer backbone and are amphiphilic; thus, they can co-assemble into composite micelles. In the composite micelles, the polymer-Oxa(IV) conjugates can release clinically widely used water soluble anticancer drug oxaliplatin (Oxa(II)) upon reduction, while polymer-DRB conjugate is thought to release DRB via acid hydrolysis in the cancer cells. In this way, combination of the hydrophilic platinum drug Oxa(II) and hydrophobic drug DRB can be realized by delivering them in one platform. Moreover, the composite micelles showed reduced systematic toxicity and greater synergistic effect than combination of small molecules of the two anticancer drugs both in vitro and in vivo; thus, this polymer based combination therapy can be useful in future clinic application. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Durability of mortars modified by the effect of combining SPA polymers and supplementary cementitious materials

    Directory of Open Access Journals (Sweden)

    Belbachir B.

    2018-01-01

    Full Text Available Nowadays, the major concern of professionals in the field of building materials is to improve the properties induced by the addition of different additives (polymers and mineral additions (Supplementary Cement Materials SCMs and to eventually adapt them to a particular application. This race towards performance has resulted in mortar formulations that are increasingly complex and rich in diversified additions. This is an industry-friendly practice since it generally yields a mortar modified by the combination of a polymer and SCMs, at low cost and low environmental impact, with an improved sustainability in the long term. In order to improve the durability of SCM-modified repair mortars, it seemed interesting to evaluate the influence of adding the styrene polyacrylic (SPA Latex on the properties of these mortars when exposed to aggressive media such as acids. Composite mortars based on pozzolanic mineral additions, containing different levels of 0.5%, 1% and 2%w latex, were stored in acid solutions, for various periods of immersion. The analysis of the microstructure of these mortars, after exposure to acid attack, was carried out by FTIR spectroscopy. The results obtained allowed to demonstrate the beneficial effect of adding the SPA polymer and the pozzolanic additions to the modified materials and to show their improved resistance to acid attacks, such as HNO3 and H3PO4 solutions at 8%. The best durability properties of the mortars modified by the combination of the polymer and the additional cementitious materials observed in this study indicate a longer service life of the repaired structure when using this type of Latex-modified repair materials.

  1. Effect of combination of irradiation and zeolite on pyrolysis of polymer materials

    International Nuclear Information System (INIS)

    Hasegawa, S.; Takesita, H.; Yoshii, F.; Makuuchi, K.; Nishimoto, S.I.

    1998-01-01

    Fo0r recycling of waste polymers, degradation behavior of polypropylene (PP) and polyoxymethylene (POM) was studied by a combination of radiolysis and thermolysis methods. The results revealed that thermal degradation temperature of PP was significantly reduced when PP was irradiated in the presence of zeolite. Irradiation induced temperature reduction depended on zeolite structure and composition as well as on the morphology of the mixture. In the presence of zeolite, a series of oxidized products were formed. Initial temperature for the pyrolysis of POM was depressed by irradiation and the irradiated POM had lower final temperature of pyrolysis in the presence of zeolite

  2. Synthetic approaches towards new polymer systems by the combination of living carbocationic and anionic polymerizations

    DEFF Research Database (Denmark)

    Feldthusen, Jesper; Ivan, Bela; Muller, Axel. H.E.

    1996-01-01

    Recent efforts to obtain block copolymers by combination of living carbocationic and anionic polymerizations are presented.When tolyl-ended polyisobutylene was used as macroinitiator of anionic polymerization of methacrylate derivatives mixtures of homopolymers and block copolymers were formed due...... to incomplete lithiation of this chain end.In another approach a new functionalization method was developed by end-quenching living polyisobutylene with 1,1-diphenylethylene. After transformation of the groups into 2,2-diphenylvinyl end groups and lithiation polymers were synthesized from protected acrylate...

  3. Evaluating the combined efficacy of polymers with fungicides for protection of museum textiles against fungal deterioration in Egypt.

    Science.gov (United States)

    Abdel-Kareem, Omar

    2010-01-01

    Fungal deterioration is one of the highest risk factors for damage of historical textile objects in Egypt. This paper represents both a study case about the fungal microflora deteriorating historical textiles in the Egyptian Museum and the Coptic museum in Cairo, and evaluation of the efficacy of several combinations of polymers with fungicides for the reinforcement of textiles and their prevention against fungal deterioration. Both cotton swab technique and biodeteriorated textile part technique were used for isolation of fungi from historical textile objects. The plate method with the manual key was used for identification of fungi. The results show that the most dominant fungi isolated from the tested textile samples belong to Alternaria, Aspergillus, Chaetomium, Penicillium and Trichoderma species. Microbiological testing was used for evaluating the usefulness of the suggested conservation materials (polymers combined with fungicides) in prevention of the fungal deterioration of ancient Egyptian textiles. Textile samples were treated with 4 selected polymers combined with two selected fungicides. Untreated and treated textile samples were deteriorated by 3 selected active fungal strains isolated from ancient Egyptian textiles. This study reports that most of the tested polymers combined with the tested fungicides prevented the fungal deterioration of textiles. Treatment of ancient textiles by suggested polymers combined with the suggested fungicides not only reinforces these textiles, but also prevents fungal deterioration and increases the durability of these textiles. The tested polymers without fungicides reduce the fungal deterioration of textiles but do not prevent it completely.

  4. Striking multiple synergies created by combining reduced graphene oxides and carbon nanotubes for polymer nanocomposites

    International Nuclear Information System (INIS)

    Song Ping’an; Liu Lina; Fu Shenyuan; Yu Youming; Jin Chunde; Wu Qiang; Zhang Yan; Li Qian

    2013-01-01

    The extraordinary properties of carbon nanotubes (CNTs) and graphene stimulate the development of advanced composites. Recently, several studies have reported significant synergies in the mechanical, electrical and thermal conductivity properties of polymer nanocomposites by incorporating their nanohybrids. In this work, we created polypropylene nanocomposites with homogeneous dispersion of CNTs and reduced graphene oxides via a facile polymer-latex-coating plus melt-mixing strategy, and investigated their synergistic effects in their viscoelastic, gas barrier, and flammability properties. Interestingly, the results show remarkable synergies, enhancing their melt modulus and viscosity, O 2 barrier, and flame retardancy properties and respectively exhibiting a synergy percentage of 15.9%, 45.3%, and 20.3%. As previously reported, we also observed remarkable synergistic effects in their tensile strength (14.3%) and Young’s modulus (27.1%), electrical conductivity (32.3%) and thermal conductivity (34.6%). These impressive results clearly point towards a new strategy to create advanced materials by adding binary combinations of different types of nanofillers. (paper)

  5. Efficient Homodifunctional Bimolecular Ring-Closure Method for Cyclic Polymers by Combining RAFT and Self-Accelerating Click Reaction.

    Science.gov (United States)

    Qu, Lin; Sun, Peng; Wu, Ying; Zhang, Ke; Liu, Zhengping

    2017-08-01

    An efficient metal-free homodifunctional bimolecular ring-closure method is developed for the formation of cyclic polymers by combining reversible addition-fragmentation chain transfer (RAFT) polymerization and self-accelerating click reaction. In this approach, α,ω-homodifunctional linear polymers with azide terminals are prepared by RAFT polymerization and postmodification of polymer chain end groups. By virtue of sym-dibenzo-1,5-cyclooctadiene-3,7-diyne (DBA) as small linkers, well-defined cyclic polymers are then prepared using the self-accelerating double strain-promoted azide-alkyne click (DSPAAC) reaction to ring-close the azide end-functionalized homodifunctional linear polymer precursors. Due to the self-accelerating property of DSPAAC ring-closing reaction, this novel method eliminates the requirement of equimolar amounts of telechelic polymers and small linkers in traditional bimolecular ring-closure methods. It facilitates this method to efficiently and conveniently produce varied pure cyclic polymers by employing an excess molar amount of DBA small linkers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Combination of Natural and Thermosensitive Polymers in Flocculation of Fine Silica Dispersions

    Directory of Open Access Journals (Sweden)

    Angel Licea-Claverie

    2013-01-01

    Full Text Available A novel strategy for faster and better flocculation in solid-liquid separation processes is reported: the use of the natural polyelectrolyte chitosan (CH2500 in combination with the biocompatible thermosensitive polymer poly(N-vinylcaprolactam (PNVCL. Silica dispersions (Aerosil OX50 were used as model and evaluated by means of analytical centrifuge, laser diffraction, and turbidimetry studies. Results show that the sedimentation velocity is doubled by addition of PNVCL and that at 45°C the density of the sediment is 33% higher, as compared to the use of CH2500 only. This results from the temperature sensitive behavior of PNVCL that phase-separate expelling water at temperatures higher than its LCST (32–34°C leading to compaction of the flocs. By using this strategy the sediment is more compact, contains less water, and contains a very small amount of biodegradable CH2500 and biocompatible PNVCL.

  7. Combined nano-imprint and photolithography (CNP) of integrated polymer optics

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Schøler, Mikkel; Kristensen, Anders

    2007-01-01

    devices are defined in SU-8 resist, doped with Rhodamine 6G laser dye, shaped as planar slab waveguides on a Si/SiO2 substrate, and with a Ist-order DFB surface corrugation forming the laser resonator. In the CNP process, a combined UV mask and nanoimprint stamp is embossed into the resist, which...... and substrate are separated, and the un-exposed resist is dissolved. Polymer waveguides are added to the system by an additional UV lithography step in a film of un-doped SU-8, which is spincoated on top of the lasers and substrate. When optically pumped at 532 nm, lasing is obtained in the wavelength range 559...

  8. Two-Channel SPR Sensor Combined Application of Polymer- and Vitreous-Clad Optic Fibers

    Directory of Open Access Journals (Sweden)

    Yong Wei

    2017-12-01

    Full Text Available By combining a polymer-clad optic fiber and a vitreous-clad optic fiber, we proposed and fabricated a novel optic fiber surface plasmon resonance (SPR sensor to conduct two-channel sensing at the same detection area. The traditional optic fiber SPR sensor has many disadvantages; for example, removing the cladding requires corrosion, operating it is dangerous, adjusting the dynamic response range is hard, and producing different resonance wavelengths in the sensing area to realize a multi-channel measurement is difficult. Therefore, in this paper, we skillfully used bare fiber grinding technology and reverse symmetry welding technology to remove the cladding in a multi-mode fiber and expose the evanescent field. On the basis of investigating the effect of the grinding angle on the dynamic range change of the SPR resonance valley wavelength and sensitivity, we combined polymer-clad fiber and vitreous-clad fiber by a smart design structure to realize at a single point a two-channel measurement fiber SPR sensor. In this paper, we obtained a beautiful spectral curve from a multi-mode fiber two-channel SPR sensor. In the detection range of the refractive rate between 1.333 RIU and 1.385 RIU, the resonance valley wavelength of channel Ⅰ shifted from 622 nm to 724 nm with a mean average sensitivity of 1961 nm/RIU and the resonance valley wavelength of channel Ⅱ shifted from 741 nm to 976 nm with a mean average sensitivity of 4519 nm/RIU.

  9. Mesoscale Simulation of Polymer Reaction Equilibrium: Combining Dissipative Particle Dynamics with Reaction Ensemble Monte Carlo. I. Polydispersed Polymer Systems

    Czech Academy of Sciences Publication Activity Database

    Lísal, Martin; Brennan, J.K.; Smith, W.R.

    2006-01-01

    Roč. 125, č. 16 (2006), s. 16490501-16490515 ISSN 0021-9606 R&D Projects: GA ČR(CZ) GA203/05/0725; GA AV ČR 1ET400720409; GA AV ČR 1ET400720507 Institutional research plan: CEZ:AV0Z40720504 Keywords : simulation * polymer Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.166, year: 2006

  10. Combined Effects of UV Exposure Duration and Mechanical Abrasion on Microplastic Fragmentation by Polymer Type.

    Science.gov (United States)

    Song, Young Kyoung; Hong, Sang Hee; Jang, Mi; Han, Gi Myung; Jung, Seung Won; Shim, Won Joon

    2017-04-18

    It is important to understand the fragmentation processes and mechanisms of plastic litter to predict microplastic production in the marine environment. In this study, accelerated weathering experiments were performed in the laboratory, with ultraviolet (UV) exposure for up to 12 months followed by mechanical abrasion (MA) with sand for 2 months. Fragmentation of low-density polyethylene (PE), polypropylene (PP), and expanded polystyrene (EPS) was evaluated under conditions that simulated a beach environment. PE and PP were minimally fragmented by MA without photooxidation by UV (8.7 ± 2.5 and 10.7 ± 0.7 particles/pellet, respectively). The rate of fragmentation by UV exposure duration increased more for PP than PE. A 12-month UV exposure and 2-month MA of PP and PE produced 6084 ± 1061 and 20 ± 8.3 particles/pellet, respectively. EPS pellets were susceptible to MA alone (4220 ± 33 particles/pellet), while the combination of 6 months of UV exposure followed by 2 months of MA produced 12,152 ± 3276 particles/pellet. The number of fragmented polymer particles produced by UV exposure and mechanical abrasion increased with decreasing size in all polymer types. The size-normalized abundance of the fragmented PE, PP, and EPS particles according to particle size after UV exposure and MA was predictable. Up to 76.5% of the initial EPS volume was unaccounted for in the final volume of pellet produced particle fragments, indicating that a large proportion of the particles had fragmented into undetectable submicron particles.

  11. Selenium-Substituted Hydroxyapatite/Biodegradable Polymer/Pamidronate Combined Scaffold for the Therapy of Bone Tumour

    Directory of Open Access Journals (Sweden)

    Ewa Oledzka

    2015-09-01

    Full Text Available The present study evaluated a new concept of combined scaffolds as a promising bone replacement material for patients with a bone tumour or bone metastasis. The scaffolds were composed of hydroxyapatite doped with selenium ions and a biodegradable polymer (linear or branched, and contained an active substance—bisphosphonate. For this purpose, a series of biodegradable polyesters were synthesized through a ring-opening polymerization of ε-caprolactone or d,l-lactide in the presence of 2-hydroxyethyl methacrylate (HEMA or hyperbranched 2,2-bis(hydroxymethylpropionic acid polyester-16-hydroxyl (bis-MPA initiators, substances often used in the synthesis of medical materials. The polymers were obtained with a high yield and a number-average molecular weight up to 45,300 (g/mol. The combined scaffolds were then manufactured by a direct compression of pre-synthesized hydroxyapatite doped with selenite or selenate ions, obtained polymer and pamidronate as a model drug. It was found that the kinetic release of the drug from the scaffolds tested in vitro under physiological conditions is strongly dependent on the physicochemical properties and average molecular weight of the polymers. Furthermore, there was good correlation with the hydrolytic biodegradation results of the scaffolds fabricated without drug. The preliminary findings suggest that the fabricated combined scaffolds could be effectively used for the sustained delivery of bioactive molecules at bone defect sites.

  12. Linear and Nonlinear Rheology Combined with Dielectric Spectroscopy of Hybrid Polymer Nanocomposites for Semiconductive Applications

    Science.gov (United States)

    Kádár, Roland; Abbasi, Mahdi; Figuli, Roxana; Rigdahl, Mikael; Wilhelm, Manfred

    2017-01-01

    The linear and nonlinear oscillatory shear, extensional and combined rheology-dielectric spectroscopy of hybrid polymer nanocomposites for semiconductive applications were investigated in this study. The main focus was the influence of processing conditions on percolated poly(ethylene-butyl acrylate) (EBA) nanocomposite hybrids containing graphite nanoplatelets (GnP) and carbon black (CB). The rheological response of the samples was interpreted in terms of dispersion properties, filler distortion from processing, filler percolation, as well as the filler orientation and distribution dynamics inside the matrix. Evidence of the influence of dispersion properties was found in linear viscoelastic dynamic frequency sweeps, while the percolation of the nanocomposites was detected in nonlinearities developed in dynamic strain sweeps. Using extensional rheology, hybrid samples with better dispersion properties lead to a more pronounced strain hardening behavior, while samples with a higher volume percentage of fillers caused a drastic reduction in strain hardening. The rheo-dielectric time-dependent response showed that in the case of nanocomposites containing only GnP, the orientation dynamics leads to non-conductive samples. However, in the case of hybrids, the orientation of the GnP could be offset by the dispersing of the CB to bridge the nanoplatelets. The results were interpreted in the framework of a dual PE-BA model, where the fillers would be concentrated mainly in the BA regions. Furthermore, better dispersed hybrids obtained using mixing screws at the expense of filler distortion via extrusion processing history were emphasized through the rheo-dielectric tests. PMID:28336857

  13. Biodegradation of naphthalenesulphonate polymers: the potential of a combined application of fungi and bacteria.

    Science.gov (United States)

    Gullotto, Antonella; Lubello, Claudio; Mannucci, Alberto; Gori, Riccardo; Munz, Giulio; Briganti, Fabrizio

    2015-01-01

    The potential of several fungi and their synergy with bacterial biomasses were evaluated as a solution for the removal of 2-naphthalensulphonic acid polymers (2-NSAPs) from petrochemical wastewater, characterized by a chemical oxygen demand (COD) greater than 9000 mg/L. The ability of fungi to grow on 2-NSAP mixtures was preliminarily investigated using a solid medium, and then the action of the selected strains, both in suspended and immobilized form, was evaluated in terms of degradation, depolymerization, sorption and an increase in biodegradability of 2-NSAP. Among the 25 fungi evaluated two, in particular, Bjerkandera adusta and Pleurotus ostreatus, have been found to significantly depolymerize 2-NSAP yielding to the corresponding monomer (2-naphthalenesulphonic acid, 2-NSA), which has been further degraded by a bacterial consortia selected in a wastewater treatment plant (WWTP). The fungal treatment alone was able to reduce the COD value up to 44%, while activated sludge removed only 9% of the initial COD. In addition, the combined treatment (fungi and bacteria) allowed an increase in the COD removal up to 62%.

  14. Surface properties and color stability of an acrylic resin combined with an antimicrobial polymer

    Directory of Open Access Journals (Sweden)

    Ana Carolina Pero

    Full Text Available INTRODUCTION: The occurrence of stomatitis is common since the surface characteristics of the dentures may act as reservoirs for microorganisms and have the potential to support biofilm formation. PURPOSE: To assess the surface properties (wettability/roughness and color stability of an acrylic resin combined with the antimicrobial polymer poly (2-tert-butylaminoethyl methacrylate (PTBAEMA. MATERIAL AND METHOD: Thirty disc-shaped specimens of an acrylic resin (Lucitone 550 were divided into three groups: 0% (control; 5% and 10% PTBAEMA. Surface roughness values (Ra were measured using a profilometer and wettability was determined through contact angle measurements using a goniometer and deionized water as a test liquid. Color data were measured with a spectrophotometer. Kruskal-Wallis and Dunn's test were used to compare roughness values. Wettability data were analyzed using ANOVA and Tukey's test. Color data were compared using the Student's t-test and ∆E values were classified according to the National Bureau of Standards (NBS. All statistical analyses were performed considering α=.05. RESULT: Significant differences (p<.05 were detected among the groups for roughness, wettability and color stability. According to the NBS, the color changes obtained in the 5% and 10% PTBAEMA groups were "appreciable" and "much appreciable", respectively. CONCLUSION: It could be concluded that PTBAEMA incorporation in an acrylic resin increased the roughness and wettability of surfaces and produced color changes with clinical relevance.

  15. SAXS Combined with UV-vis Spectroscopy and QELS: Accurate Characterization of Silver Sols Synthesized in Polymer Matrices.

    Science.gov (United States)

    Bulavin, Leonid; Kutsevol, Nataliya; Chumachenko, Vasyl; Soloviov, Dmytro; Kuklin, Alexander; Marynin, Andrii

    2016-12-01

    The present work demonstrates a validation of small-angle X-ray scattering (SAXS) combining with ultra violet and visible (UV-vis) spectroscopy and quasi-elastic light scattering (QELS) analysis for characterization of silver sols synthesized in polymer matrices. Polymer matrix internal structure and polymer chemical nature actually controlled the sol size characteristics. It was shown that for precise analysis of nanoparticle size distribution these techniques should be used simultaneously. All applied methods were in good agreement for the characterization of size distribution of small particles (less than 60 nm) in the sols. Some deviations of the theoretical curves from the experimental ones were observed. The most probable cause is that nanoparticles were not entirely spherical in form.

  16. Dynamics of combined electron beam and laser dispersion of polymers in vacuum

    OpenAIRE

    Luchnikov, P. A.; Rogachev, A. V.; Yarmolenko, M. A.; Rogachev, A. A.; Bespalko (Bespal'ko), Anatoly Alekseevich

    2016-01-01

    The mechanisms of the impact of the laser assisting effect on the dispersion kinetics and on the structure of the deposited layers in electron beam dispersion of a polymer target were analyzed. The proposed model and analytical expressions adequately describe the kinetic dependence of the polymer materials dispersion rate in a vacuum on the intensity of laser processing of their dispersion zone.

  17. Linear and Nonlinear Rheology Combined with Dielectric Spectroscopy of Hybrid Polymer Nanocomposites for Semiconductive Applications

    Directory of Open Access Journals (Sweden)

    Roland Kádár

    2017-01-01

    Full Text Available The linear and nonlinear oscillatory shear, extensional and combined rheology-dielectric spectroscopy of hybrid polymer nanocomposites for semiconductive applications were investigated in this study. The main focus was the influence of processing conditions on percolated poly(ethylene-butyl acrylate (EBA nanocomposite hybrids containing graphite nanoplatelets (GnP and carbon black (CB. The rheological response of the samples was interpreted in terms of dispersion properties, filler distortion from processing, filler percolation, as well as the filler orientation and distribution dynamics inside the matrix. Evidence of the influence of dispersion properties was found in linear viscoelastic dynamic frequency sweeps, while the percolation of the nanocomposites was detected in nonlinearities developed in dynamic strain sweeps. Using extensional rheology, hybrid samples with better dispersion properties lead to a more pronounced strain hardening behavior, while samples with a higher volume percentage of fillers caused a drastic reduction in strain hardening. The rheo-dielectric time-dependent response showed that in the case of nanocomposites containing only GnP, the orientation dynamics leads to non-conductive samples. However, in the case of hybrids, the orientation of the GnP could be offset by the dispersing of the CB to bridge the nanoplatelets. The results were interpreted in the framework of a dual PE-BA model, where the fillers would be concentrated mainly in the BA regions. Furthermore, better dispersed hybrids obtained using mixing screws at the expense of filler distortion via extrusion processing history were emphasized through the rheo-dielectric tests.

  18. Use of polymer combinations in the preparation of solid dispersions of a thermally unstable drug by hot-melt extrusion

    Directory of Open Access Journals (Sweden)

    Jia Liu

    2013-07-01

    Full Text Available The objective of the study was to prepare solid dispersions containing a thermally unstable drug by hot-melt extrusion (HME. Carbamazepine (CBZ was selected as model drug and combinations of Kollidon VA64 (VA64, Soluplus (SOL and Eudragit EPO (EPO were utilized as carriers. Preformulation was conducted to identify the suitability of polymer combinations based on solubility parameters, differential scanning calorimetry (DSC, hot stage microscopy and thermogravimetric analysis. Physicochemical properties of solid dispersions were determined by DSC, X-ray diffraction, fourier transform infrared spectroscopy, dissolution and accelerated stability testing. The results show that drug-polymer miscibility at temperatures below the melting point (Tm of CBZ was improved by combining EPO with VA64 or SOL. With 30% drug loading in a solid dispersion in SOL:EPO (1:1, w/w, CBZ was mainly present in an amorphous form accompanied by a small amount of a microcrystalline form. The dissolution rate of the solid dispersion was significantly increased (approximately 90% within 5 min compared to either the pure drug (approximately 85% within 60 min or the corresponding physical mixture (approximately 80% within 60 min before and after storage. The solid dispersion in SOL:EPO (1:1, w/w was relatively stable at 40 °C/75% RH under CBZ tablet packaging conditions for at least 3 months. In conclusion, polymer combinations that improve drug-polymer miscibility at an HME processing temperature below the Tm of a drug appear to be beneficial in the preparation of solid dispersions containing thermally unstable drugs.

  19. Log-pile photonic crystal of CdS-polymer nanocomposites fabricated by combination of two-photon polymerization and in situ synthesis

    International Nuclear Information System (INIS)

    Sun, Z.-B.; Dong, X.-Z.; Chen, W.-Q.; Duan, X.-M.; Nakanishi, S.; Kawata, S.

    2007-01-01

    A log-pile photonic crystal of CdS nanoparticles-polymer nanocomposites was successfully fabricated by a novel method combining the two-photon polymerization technique and in situ synthesis of CdS nanoparticles in a polymer matrix. The photonic band gap of the three-dimensional (3D) log-pile photonic crystal is confirmed and becomes more effective for CdS nanoparticles-polymer nanocomposites than polymer doped with Cd 2+ ions, because the nanocomposites possess a higher refractive index than the polymer. The proposed concept in the new fabrication method for a 3D microstructure of polymer nanocomposites should be of critical importance in providing a general methodology for functionalization of materials via functional nanocomposites used in the field of laser microstructure fabrication. (orig.)

  20. Optimal design of high temperature metalized thin-film polymer capacitors: A combined numerical and experimental method

    Science.gov (United States)

    Wang, Zhuo; Li, Qi; Trinh, Wei; Lu, Qianli; Cho, Heejin; Wang, Qing; Chen, Lei

    2017-07-01

    The objective of this paper is to design and optimize the high temperature metalized thin-film polymer capacitor by a combined computational and experimental method. A finite-element based thermal model is developed to incorporate Joule heating and anisotropic heat conduction arising from anisotropic geometric structures of the capacitor. The anisotropic thermal conductivity and temperature dependent electrical conductivity required by the thermal model are measured from the experiments. The polymer represented by thermally crosslinking benzocyclobutene (BCB) in the presence of boron nitride nanosheets (BNNSs) is selected for high temperature capacitor design based on the results of highest internal temperature (HIT) and the time to achieve thermal equilibrium. The c-BCB/BNNS-based capacitor aiming at the operating temperature of 250 °C is geometrically optimized with respect to its shape and volume. "Safe line" plot is also presented to reveal the influence of the cooling strength on capacitor geometry design.

  1. The material combining conducting polymer and ionic liquid: hydrogen bonding interactions between polyaniline and imidazolium salt

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Dybal, Jiří; Trchová, Miroslava

    2014-01-01

    Roč. 197, November (2014), s. 168-174 ISSN 0379-6779 R&D Projects: GA ČR(CZ) GA13-08944S Institutional support: RVO:61389013 Keywords : conducting polymer * conductivity * imidazolium salt Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.252, year: 2014

  2. Superhydrophobic Thin Films Fabricated by Reactive Layer-by-Layer Assembly of Azlactone-Functionalized Polymers.

    Science.gov (United States)

    Buck, Maren E; Schwartz, Sarina C; Lynn, David M

    2010-09-11

    We report an approach to the fabrication of superhydrophobic thin films that is based on the 'reactive' layer-by-layer assembly of azlactone-containing polymer multilayers. We demonstrate that films fabricated from alternating layers of the azlactone functionalized polymer poly(2-vinyl-4,4-dimethylazlactone) (PVDMA) and poly(ethyleneimine) (PEI) exhibit micro- and nanoscale surface features that result in water contact angles in excess of 150º. Our results reveal that the formation of these surface features is (i) dependent upon film thickness (i.e., the number of layers of PEI and PVDMA deposited) and (ii) that it is influenced strongly by the presence (or absence) of cyclic azlactone-functionalized oligomers that can form upon storage of the 2-vinyl-4,4-dimethylazlactone (VDMA) used to synthesize PVDMA. For example, films fabricated using polymers synthesized in the presence of these oligomers exhibited rough, textured surfaces and superhydrophobic behavior (i.e., advancing contact angles in excess of 150º). In contrast, films fabricated from PVDMA polymerized in the absence of this oligomer (e.g., using freshly distilled monomer) were smooth and only moderately hydrophobic (i.e., advancing contact angles of ~75º). The addition of authentic, independently synthesized oligomer to samples of distilled VDMA at specified and controlled concentrations permitted reproducible fabrication of superhydrophobic thin films on the surfaces of a variety of different substrates. The surfaces of these films were demonstrated to be superhydrophobic immediately after fabrication, but they became hydrophilic after exposure to water for six days. Additional experiments demonstrated that it was possible to stabilize and prolong the superhydrophobic properties of these films (e.g., advancing contact angles in excess of 150° even after complete submersion in water for at least six weeks) by exploiting the reactivity of residual azlactones to functionalize the surfaces of the films

  3. Combining Pickering Emulsion Polymerization with Molecular Imprinting to Prepare Polymer Microspheres for Selective Solid-Phase Extraction of Malachite Green

    Directory of Open Access Journals (Sweden)

    Weixin Liang

    2017-08-01

    Full Text Available Malachite green (MG is currently posing a carcinogenic threat to the safety of human lives; therefore, it is highly desirable to develop an effective method for fast trace detection of MG. Herein, for the first time, this paper presents a systematic study on polymer microspheres, being prepared by combined Pickering emulsion polymerization and molecular imprinting, to detect and purify MG. The microspheres, molecularly imprinted with MG, show enhanced adsorption selectivity to MG, despite a somewhat lowered adsorption capacity, as compared to the counterpart without molecular imprinting. Structural features and adsorption performance of these microspheres are elucidated by different characterizations and kinetic and thermodynamic analyses. The surface of the molecularly imprinted polymer microspheres (M-PMs exhibits regular pores of uniform pore size distribution, endowing M-PMs with impressive adsorption selectivity to MG. In contrast, the microspheres without molecular imprinting show a larger average particle diameter and an uneven porous surface (with roughness and a large pore size, causing a lower adsorption selectivity to MG despite a higher adsorption capacity. Various adsorption conditions are investigated, such as pH and initial concentration of the solution with MG, for optimizing the adsorption performance of M-PMs in selectively tackling MG. The adsorption kinetics and thermodynamics are deeply discussed and analyzed, so as to provide a full picture of the adsorption behaviors of the polymer microspheres with and without the molecular imprinting. Significantly, M-PMs show promising solid-phase extraction column applications for recovering MG in a continuous extraction manner.

  4. Study of wood polymer combinations for various woods of Kashmir - Part I

    International Nuclear Information System (INIS)

    Mohan, H.; Rao, K.N.

    1977-01-01

    The report describes the studies conducted to upgrade inferior woods in Kashmir by the method of radiation polymerisation. The normal qualities of wood are retained and modifications brought about in unfavourable properties such as softness, dimensional instability, hygroscopicity and compressibility. Various changes in properties of wood after the modifications are discussed. It is shown that 50% of polymer content in wood considerably improves the physical and mechanical properties. (author)

  5. Compaction properties, drug release kinetics and fronts movement studies of matrices combining mixtures of swellable and inert polymers. III: effect of polymer substitution type.

    Science.gov (United States)

    Escudero, J J; Ferrero, C; Casas, M; Jiménez-Castellanos, M R

    2012-09-15

    Theophylline radial release from cellulose derivatives with different substitution type (HPMC K4M, HPC H, MC A4M) matrix tablets has been modulated by the introduction of a new inert polymeric excipient, at different proportions (75, 50, 25%). The new polymer was hydroxypropylcellulose-methyl methacrylate (HCMMA), which was dried either in a vacuum oven (OD-HCMMA) or freeze-dried (FD-HCMMA). MC A4M and its mixtures presented the best compaction properties results, especially mixed with FD-HCMMA, according to 100% mixtures. Only high levels of HCMMA (75%) in the matrices showed interesting differences to drug release modulation. Also, at this proportion (75:25), the HPC H mixtures presented the highest differences in relation with OD or FD HCMMA respect to the other cellulose polymers. HPMC K4M and HPC H mixtures showed a combination of diffusion and erosion release mechanisms. The last one was nearly negligible in MC A4M mixtures, according with its highest diffusion rate constant values, and the absence of hydroxypropyl substituents. Only HPMC K4M mixtures presented a diffusion front that moves outwards, while HPC H and MC A4M moves inwards. The modulation of theophylline radial release was obtained using a high percentage of HCMMA, and the use of two cellulosic ethers, one of them with just one type of substituent (MC A4M or HPC H) and the other with two types of substituent (HPMC K4M). Another possibility is changing the HCMMA copolymer (OD or FD) in the 75/25 mixture with HPC. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Measurements of turbulent velocity profiles in combined system of polymer additives and riblets; Kobunshi tenkazai to riblet tono fukugokei ni okeru ranryu sokudo bunpu no sokutei

    Energy Technology Data Exchange (ETDEWEB)

    Mizunuma, H. [Tokyo Metropolitan Univ., Tokyo (Japan); Ban, T. [Hino Motors, Ltd., Tokyo (Japan)

    2000-03-25

    In the combined system of polymer additives and riblets, the polymer additives expand the range of non-dimensionalized riblet width s{sup +} where the riblets reduce the frictional drag. Although in the higher region of s{sup +} the riblets increase the frictional drag as the rough surface, the polymer additives thicken the wall layer, which dumps the drag increase due to riblets and then gives the benefical combined effect in this higher region of s{sup +}. Based on this scinario, the velocity profile and the pipe frictional coefficient for the combined system were derived from the velocity profile of each system. The turbulent velocity profiles were measured for the combined system using a laser Doppler velocimetry. The measured results agreed well with the derived prediction for the combined system. (author)

  7. Combination of Polymer Technology and Carbon Nanotube Array for the Development of an Effective Drug Delivery System at Cellular Level

    Directory of Open Access Journals (Sweden)

    Riggio Cristina

    2009-01-01

    Full Text Available Abstract In this article, a carbon nanotube (CNT array-based system combined with a polymer thin film is proposed as an effective drug release device directly at cellular level. The polymeric film embedded in the CNT array is described and characterized in terms of release kinetics, while in vitro assays on PC12 cell line have been performed in order to assess the efficiency and functionality of the entrapped agent (neural growth factor, NGF. PC12 cell differentiation, following incubation on the CNT array embedding the alginate delivery film, demonstrated the effectiveness of the proposed solution. The achieved results indicate that polymeric technology could be efficiently embedded in CNT array acting as drug delivery system at cellular level. The implication of this study opens several perspectives in particular in the field of neurointerfaces, combining several functions into a single platform.

  8. Combined, Independent Small Molecule Release and Shape Memory via Nanogel-Coated Thiourethane Polymer Networks.

    Science.gov (United States)

    Dailing, Eric A; Nair, Devatha P; Setterberg, Whitney K; Kyburz, Kyle A; Yang, Chun; D'Ovidio, Tyler; Anseth, Kristi S; Stansbury, Jeffrey W

    2016-01-28

    Drug releasing shape memory polymers (SMPs) were prepared from poly(thiourethane) networks that were coated with drug loaded nanogels through a UV initiated, surface mediated crosslinking reaction. Multifunctional thiol and isocyanate monomers were crosslinked through a step-growth mechanism to produce polymers with a homogeneous network structure that exhibited a sharp glass transition with 97% strain recovery and 96% shape fixity. Incorporating a small stoichiometric excess of thiol groups left pendant functionality for a surface coating reaction. Nanogels with diameter of approximately 10 nm bearing allyl and methacrylate groups were prepared separately via solution free radical polymerization. Coatings with thickness of 10-30 μm were formed via dip-coating and subsequent UV-initiated thiol-ene crosslinking between the SMP surface and the nanogel, and through inter-nanogel methacrylate homopolymerization. No significant change in mechanical properties or shape memory behavior was observed after the coating process, indicating that functional coatings can be integrated into an SMP without altering its original performance. Drug bioactivity was confirmed via in vitro culturing of human mesenchymal stem cells with SMPs coated with dexamethasone-loaded nanogels. This article offers a new strategy to independently tune multiple functions on a single polymeric device, and has broad application toward implantable, minimally invasive medical devices such as vascular stents and ocular shunts, where local drug release can greatly prolong device function.

  9. Study of the quality of radiation cured wood-polymer-combination

    International Nuclear Information System (INIS)

    Leclerq, A.; Lacroix, J.P.

    1980-01-01

    The physical properties like density and the total volumetric shrinkage and the mechanical properties like the static and dynamic bending strength, the axial compressive and the transversal cohesive strength were investigated on three type of wood: the beech (fagus silvatica) the poplar (populus sp.) and the Norwege pine (pinus silvestris) with and without impregnation with methylmethacrylate. The effect polymer treatment on the physical properties and the mechanical properties of the wood. The effect of sampling zone of wood on the improvement on its quality is also discussed. Every kind of wood is modified in its qualities especially the density, the shrinkage, the hardness, the static flexion strength and the compressive strength by the arrylic treatment. (Data)

  10. A new system for posterior restorations: a combination of ceramic optimized polymer and fiber-reinforced composite.

    Science.gov (United States)

    Rosenthal, L; Trinkner, T; Pescatore, C

    1997-01-01

    Due to the need for increased strength characteristics and enhanced aesthetic expectations of the patients, metal-free, aesthetic restorative systems for the anterior and posterior dentition are currently available. A new "space-age" restorative material has been developed that is a combination of a ceramic optimized polymer (Ceromer) (Targis/Vectris, Ivoclar Williams, Amherst, NY) and a fiber-reinforced composite framework material. The purpose of this article is to discuss the qualities that render this material particularly suitable for a variety of indications, including laboratory-fabricated restorations for the stress-bearing posterior regions. The material lends itself to diversification. Its indication for inlays, onlays, full-coverage crown restorations, and conservative single pontic inlay bridges is presented.

  11. Research on the Mechanical Properties of a Glass Fiber Reinforced Polymer-Steel Combined Truss Structure

    Directory of Open Access Journals (Sweden)

    Pengfei Liu

    2014-01-01

    Full Text Available An assembled plane truss structure used for vehicle loading is designed and manufactured. In the truss, the glass fiber reinforced polymer (GFRP tube and the steel joint are connected by a new technology featuring a pretightened tooth connection. The detailed description for the rod and node design is introduced in this paper, and a typical truss panel is fabricated. Under natural conditions, the short-term load test and long-term mechanical performance test for one year are performed to analyze its performance and conduct a comparative analysis for a reasonable FEM model. The study shows that the design and fabrication for the node of an assembled truss panel are convenient, safe, and reliable; because of the creep control design of the rods, not only does the short-term structural stiffness meet the design requirement but also the long-term creep deformation tends towards stability. In addition, no significant change is found in the elastic modules, so this structure can be applied in actual engineering. Although the safety factor for the strength of the composite rods is very large, it has a lightweight advantage over the steel truss for the low density of GFRP. In the FEM model, simplifying the node as a hinge connection relatively conforms to the actual status.

  12. VUV treatment combined with mechanical strain of stretchable polymer foils resulting in cell alignment

    Energy Technology Data Exchange (ETDEWEB)

    Barb, R.-A. [Institute of Applied Physics, Johannes Kepler University Linz (Austria); Magnus, B. [Innovacell Biotechnologie AG, Innsbruck (Austria); Innerbichler, S. [Innerbichler GmbH, Breitenbach am Inn (Austria); Greunz, T. [CDL-MS-MACH, Johannes Kepler University Linz (Austria); Wiesbauer, M. [Institute of Applied Physics, Johannes Kepler University Linz (Austria); Marksteiner, R. [Innovacell Biotechnologie AG, Innsbruck (Austria); Stifter, D. [CDL-MS-MACH, Johannes Kepler University Linz (Austria); Heitz, J., E-mail: johannes.heitz@jku.at [Institute of Applied Physics, Johannes Kepler University Linz (Austria)

    2015-01-15

    Highlights: • Elastic polyurethane (PU) foils were exposed to the vacuum-UV in reactive atmosphere. • The photomodification resulted in improved cytocompatibilty. • Parallel microgrooves formed on the irradiated PU surfaces after strong elongation. • Cells seeded onto microgrooves aligned their shapes in the direction of the grooves. • Elongation occurred also for cells on PU subjected to cyclic mechanical stretching. - Abstract: Cell-alignment along a defined direction can have a direct effect on the cell functionality and differentiation. Oriented micro- or nanotopographic structures on cell culture substrates can induce cell-alignment. Surface chemistry, wettability, and stiffness of the substrate are also important material features as they strongly influence the cell–substrate interactions. For improved bio-compatibility, highly elastic polyurethane (PU) foils were exposed to the vacuum-UV (VUV) light of a Xe{sub 2}{sup *} excimer lamp at 172 nm in a nitrogen containing atmosphere (N{sub 2} or NH{sub 3}). The irradiation resulted in a change in the chemical surface composition. Additionally, the formation of regular parallel microgrooves was observed on the irradiated surfaces after strong uni-axial deformation (i.e., more than about 50% strain) of the photo-modified PU foils. Cell seeding experiments demonstrated that the VUV modified polymer foils strongly enhance cell adhesion and proliferation. Cells seeded onto microgrooves aligned their shapes and elongated in the direction of the grooves. A similar effect was observed for cells seeded on photo-modified PU foils subjected to cyclic mechanical stretching at lower strain levels (i.e., typically 10% strain) without groove-formation. The cells had also here an elongated shape, however they not always align in a defined direction relative to the stretching.

  13. Bioactive cell-derived matrices combined with polymer mesh scaffold for osteogenesis and bone healing.

    Science.gov (United States)

    Kim, In Gul; Hwang, Mintai P; Du, Ping; Ko, Jaehoon; Ha, Chul-won; Do, Sun Hee; Park, Kwideok

    2015-05-01

    Successful bone tissue engineering generally requires an osteoconductive scaffold that consists of extracellular matrix (ECM) to mimic the natural environment. In this study, we developed a PLGA/PLA-based mesh scaffold coated with cell-derived extracellular matrix (CDM) for the delivery of bone morphogenic protein (BMP-2), and assessed the capacity of this system to provide an osteogenic microenvironment. Decellularized ECM from human lung fibroblasts (hFDM) was coated onto the surface of the polymer mesh scaffolds, upon which heparin was then conjugated onto hFDM via EDC chemistry. BMP-2 was subsequently immobilized onto the mesh scaffolds via heparin, and released at a controlled rate. Human placenta-derived mesenchymal stem cells (hPMSCs) were cultured in such scaffolds and subjected to osteogenic differentiation for 28 days in vitro. The results showed that alkaline phosphatase (ALP) activity, mineralization, and osteogenic marker expression were significantly improved with hPMSCs cultured in the hFDM-coated mesh scaffolds compared to the control and fibronectin-coated ones. In addition, a mouse ectopic and rat calvarial bone defect model was used to examine the feasibility of current platform to induce osteogenesis as well as bone regeneration. All hFDM-coated mesh groups exhibited a significant increase of newly formed bone and in particular, hFDM-coated mesh scaffold loaded with a high dose of BMP-2 exhibited a nearly complete bone defect healing as confirmed via micro-CT and histological observation. This work proposes a great potency of using hFDM (biophysical) coupled with BMP-2 (biochemical) as a promising osteogenic microenvironment for bone tissue engineering applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Super-resolution fluorescence imaging of nanoimprinted polymer patterns by selective fluorophore adsorption combined with redox switching

    KAUST Repository

    Yabiku, Y.

    2013-10-22

    We applied a super-resolution fluorescence imaging based on selective adsorption and redox switching of the fluorescent dye molecules for studying polymer nanostructures. We demonstrate that nano-scale structures of polymer thin films can be visualized with the image resolution better than 80 nm. The method was applied to image 100 nm-wide polymer nanopatterns fabricated by thermal nanoimprinting. The results point to the applicability of the method for evaluating residual polymer thin films and dewetting defect of the polymer resist patterns which are important for the quality control of the fine nanoimprinted patterns. 2013 Author(s).

  15. Lidocaine carboxymethylcellulose with gelatine co-polymer hydrogel delivery by combined microneedle and ultrasound.

    Science.gov (United States)

    Nayak, Atul; Babla, Hiten; Han, Tao; Das, Diganta Bhusan

    2016-01-01

    A study that combines microneedles (MNs) and sonophoresis pre-treatment was explored to determine their combined effects on percutaneous delivery of lidocaine from a polymeric hydrogel formulation. Varying ratios of carboxymethylcellulose and gelatine (NaCMC/gel ranges 1:1.60-1:2.66) loaded with lidocaine were prepared and characterized for zeta potential and particle size. Additionally, variations in the formulation drying techniques were explored during the formulation stage. Ex vivo permeation studies using Franz diffusion cells measured lidocaine permeation through porcine skin after pre-treatment with stainless steel MNs and 20 kHz sonophoresis for 5-and 10-min durations. A stable formulation was related to a lower gelatine mass ratio because of smaller mean particle sizes and high zeta potential. Lidocaine permeability in skin revealed some increases in permeability from combined MN and ultrasound pre-treatment studies. Furthermore, up to 4.8-fold increase in the combined application was observed compared with separate pre-treatments after 30 min. Sonophoresis pre-treatment alone showed insignificant enhancement in lidocaine permeation during the initial 2 h period. MN application increased permeability at a time of 0.5 h for up to ∼17 fold with an average up to 4 fold. The time required to reach therapeutic levels of lidocaine was decreased to less than 7 min. Overall, the attempted approach promises to be a viable alternative to conventional lidocaine delivery methods involving painful injections by hypodermic needles. The mass transfer effects were fairly enhanced and the lowest amount of lidocaine in skin was 99.7% of the delivered amount at a time of 3 h for lidocaine NaCMC/GEL 1:2.66 after low-frequency sonophoresis and MN treatment.

  16. Combining Diffusion NMR and Small-Angle Neutron Scattering Enables Precise Measurements of Polymer Chain Compression in a Crowded Environment

    Science.gov (United States)

    Palit, Swomitra; He, Lilin; Hamilton, William A.; Yethiraj, Arun; Yethiraj, Anand

    2017-03-01

    The effect of particles on the behavior of polymers in solution is important in a number of important phenomena such as the effect of "crowding" proteins in cells, colloid-polymer mixtures, and nanoparticle "fillers" in polymer solutions and melts. In this Letter, we study the effect of spherical inert nanoparticles (which we refer to as "crowders") on the diffusion coefficient and radius of gyration of polymers in solution using pulsed-field-gradient NMR and small-angle neutron scattering (SANS), respectively. The diffusion coefficients exhibit a plateau below a characteristic polymer concentration, which we identify as the overlap threshold concentration c⋆. Above c⋆, in a crossover region between the dilute and semidilute regimes, the (long-time) self-diffusion coefficients are found, universally, to decrease exponentially with polymer concentration at all crowder packing fractions, consistent with a structural basis for the long-time dynamics. The radius of gyration obtained from SANS in the crossover regime changes linearly with an increase in polymer concentration, and must be extrapolated to c⋆ in order to obtain the radius of gyration of an individual polymer chain. When the polymer radius of gyration and crowder size are comparable, the polymer size is very weakly affected by the presence of crowders, consistent with recent computer simulations. There is significant chain compression, however, when the crowder size is much smaller than the polymer radius gyration.

  17. Combinational Effect of Cell Adhesion Biomolecules and Their Immobilized Polymer Property to Enhance Cell-Selective Adhesion

    Directory of Open Access Journals (Sweden)

    Rio Kurimoto

    2016-01-01

    Full Text Available Although surface immobilization of medical devices with bioactive molecules is one of the most widely used strategies to improve biocompatibility, the physicochemical properties of the biomaterials significantly impact the activity of the immobilized molecules. Herein we investigate the combinational effects of cell-selective biomolecules and the hydrophobicity/hydrophilicity of the polymeric substrate on selective adhesion of endothelial cells (ECs, fibroblasts (FBs, and smooth muscle cells (SMCs. To control the polymeric substrate, biomolecules are immobilized on thermoresponsive poly(N-isopropylacrylamide-co-2-carboxyisopropylacrylamide (poly(NIPAAm-co-CIPAAm-grafted glass surfaces. By switching the molecular conformation of the biomolecule-immobilized polymers, the cell-selective adhesion performances are evaluated. In case of RGDS (Arg-Gly-Asp-Ser peptide-immobilized surfaces, all cell types adhere well regardless of the surface hydrophobicity. On the other hand, a tri-Arg-immobilized surface exhibits FB-selectivity when the surface is hydrophilic. Additionally, a tri-Ile-immobilized surface exhibits EC-selective cell adhesion when the surface is hydrophobic. We believe that the proposed concept, which is used to investigate the biomolecule-immobilized surface combination, is important to produce new biomaterials, which are highly demanded for medical implants and tissue engineering.

  18. Enhanced neuronal cell differentiation combining biomimetic peptides and a carbon nanotube-polymer scaffold.

    Science.gov (United States)

    Scapin, Giorgia; Salice, Patrizio; Tescari, Simone; Menna, Enzo; De Filippis, Vincenzo; Filippini, Francesco

    2015-04-01

    Carbon nanotubes are attractive candidates for the development of scaffolds able to support neuronal growth and differentiation thanks to their ability to conduct electrical stimuli, to interface with cells and to mimic the neural environment. We developed a biocompatible composite scaffold, consisting of multi-walled carbon nanotubes dispersed in a poly-L-lactic acid matrix able to support growth and differentiation of human neuronal cells. Moreover, to mimic guidance cues from the neural environment, we also designed synthetic peptides, derived from L1 and LINGO1 proteins. Such peptides could positively modulate neuronal differentiation, which is synergistically improved by the combination of the nanocomposite scaffold and the peptides, thus suggesting a prototype for the development of implants for long-term neuronal growth and differentiation. From the clinical editor: The study describes the design and preparation of nanocomposite scaffolds with multi-walled carbon nanotubes in a poly-L-lactic acid matrix. This compound used in combination with peptides leads to synergistic effects in supporting neuronal cell growth and differentiation. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. The Olefin Metathesis Reactions Combined with Organo-Iron Arene Activation Towards Dendrimers, and Polymers

    Science.gov (United States)

    Astruc, Didier; Martinez, Victor

    The subjects treated in the two lectures of the North Atlantic Treaty Organization (NATO) summer course are (1) the combination of arene activation and perfunctionalization using organo-iron chemistry with olefin metathesis incuding metathesis of dendritic polyolefin molecules; (2) the synthesis of metallodendritic benzylidene complexes that catalyse ring-opening metathesis polymerization (ROMP) under ambient conditions and the formation of dendritic stars; (3) the use of stoichiometric and catalytic electron-transfer processes with standard reservoirs of electrons (reductants) or electron holes (oxidants) iron complexes to achieve noteworthy metathesis reactions or synthesize compounds that are useful in metathesis. Only the two first topics are treated in this chapter, and interested readers can find references concerning the third aspect called in the introduction and subsequently cited in the reference list.

  20. Hybrid approach combining dissipative particle dynamics and finite-difference diffusion model: simulation of reactive polymer coupling and interfacial polymerization.

    Science.gov (United States)

    Berezkin, Anatoly V; Kudryavtsev, Yaroslav V

    2013-10-21

    A novel hybrid approach combining dissipative particle dynamics (DPD) and finite difference (FD) solution of partial differential equations is proposed to simulate complex reaction-diffusion phenomena in heterogeneous systems. DPD is used for the detailed molecular modeling of mass transfer, chemical reactions, and phase separation near the liquid∕liquid interface, while FD approach is applied to describe the large-scale diffusion of reactants outside the reaction zone. A smooth, self-consistent procedure of matching the solute concentration is performed in the buffer region between the DPD and FD domains. The new model is tested on a simple model system admitting an analytical solution for the diffusion controlled regime and then applied to simulate practically important heterogeneous processes of (i) reactive coupling between immiscible end-functionalized polymers and (ii) interfacial polymerization of two monomers dissolved in immiscible solvents. The results obtained due to extending the space and time scales accessible to modeling provide new insights into the kinetics and mechanism of those processes and demonstrate high robustness and accuracy of the novel technique.

  1. Revealing the structural detail of individual polymers using a combination of electrospray deposition and UHV-STM

    DEFF Research Database (Denmark)

    Jethwa, Siddharth; Madsen, Mikael; Knudsen, Jakob Back

    2017-01-01

    A phenylene vinylene polymer derivative is deposited onto a Au(111) surface under Ultra-High Vacuum (UHV) conditions using electrospray ionisation deposition and characterised using Scanning Tunnelling Microscopy (STM). High resolution STM images reveal the polymer structure on the monomeric scale...

  2. In-situ observation of dynamic water behavior in polymer electrolyte fuel cell by combined method of Small-Angle Neutron Scattering and Neutron Radiography

    International Nuclear Information System (INIS)

    Putra, A; Yamaguchi, D; Koizumi, S; Hashimoto, T; Iwase, H; Maekawa, Y; Matsubayashi, M

    2010-01-01

    In-situ observation was conducted on an operating polymer electrolyte fuel cell with a combined method of small-angle neutron scattering (SANS) and neutron radiography (NR). The combined measurement system has been recently developed to visualize water in a wide length scale from nano- to millimeter and successfully detected a spatial distribution of the water generated in individual cell elements; NR macroscopically detected the water in a gas diffusion layer and a flow-field, whereas SANS microscopically did in a membrane electrode assembly. In particular SANS was found to be a strong tool to make a rather precise analysis on the water content inside of ion conducting channels of polymer electrolyte membrane.

  3. Is the combination of cellulosic polymers and anionic surfactants a good strategy for ensuring physical stability of BCS Class II drug nanosuspensions?

    Science.gov (United States)

    Bilgili, Ecevit; Li, Meng; Afolabi, Afolawemi

    2016-01-01

    Ensuring the physical stability of drug nanosuspensions prepared via wet media milling has been a challenge for pharmaceutical scientists. The aim of this study is to assess the combined use of non-ionic cellulosic polymers and anionic surfactants in stabilizing multiple drug nanosuspensions. Particle size of five drugs, i.e. azodicarbonamide (AZD), fenofibrate (FNB), griseofulvin (GF), ibuprofen (IBU) and phenylbutazone (PB) was reduced separately in an aqueous solution of hydroxypropyl cellulose (HPC) with/without sodium dodecyl sulfate (SDS) via a stirred media mill. Laser diffraction, scanning electron microscopy, thermal analysis, rheometry and electrophoresis were used to evaluate the breakage kinetics, storage stability, electrostatic repulsion and stabilizer adsorption. Without SDS, drug particles exhibited aggregation to different extents; FNB and GF particles aggregated the most due to low zeta potential and insufficient steric stabilization. Although aggregation in all milled suspensions was reduced due to HPC-SDS combination, FNB and IBU showed notable growth during 7-day storage. It is concluded that the combination of non-ionic cellulosic polymers and anionic surfactants is generally viable for ensuring the physical stability of wet-milled drug nanosuspensions, provided that the surfactant concentration is optimized to mitigate the Ostwald ripening, whereas cellulosic polymers alone may provide stability for some drug suspensions.

  4. Gamma scintigraphic evaluation of floating gastroretentive tablets of metformin HCl using a combination of three natural polymers in rabbits

    Directory of Open Access Journals (Sweden)

    Razavi M

    2015-08-01

    Full Text Available Mahboubeh Razavi,1 Hamed Karimian,1 Chai Hong Yeong,2 Lip Yong Chung,1 Shaik Nyamathulla,1 Mohamed Ibrahim Noordin1,3 1Department of Pharmacy, Faculty of Medicine, University of Malaya, 2Department of Biomedical Imaging and University Malaya Research Imaging Centre, Faculty of Medicine, University of Malaya, 3Center for Natural Products and Drug Discovery (CENAR, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia Abstract: The present research was aimed at formulating a metformin HCl sustained-release formulation from a combination of polymers, using the wet granulation technique. A total of 16 formulations (F1–F16 were produced using different combinations of the gel-forming polymers: tamarind kernel powder, salep (palmate tubers of Orchis morio, and xanthan. Post-compression studies showed that there were no interactions between the active drug and the polymers. Results of in vitro drug-release studies indicated that the F10 formulation which contained 5 mg of tamarind kernel powder, 33.33 mg of xanthan, and 61.67 mg of salep could sustain a 95% release in 12 hours. The results also showed that F2 had a 55% similarity factor with the commercial formulation (C-ER, and the release kinetics were explained with zero order and Higuchi models. The in vivo study was performed in New Zealand White rabbits by gamma scintigraphy; the F10 formulation was radiolabeled using samarium (III oxide (153Sm2O3 to trace transit of the tablets in the gastrointestinal tract. The in vivo data supported the retention of F10 formulation in the gastric region for 12 hours. In conclusion, the use of a combination of polymers in this study helped to develop an optimal gastroretentive drug-delivery system with improved bioavailability, swelling, and floating characteristics. Keywords: gastroretentive drug delivery, gamma scintigraphy, sustain-release study, salep, tamarind seed, xanthan

  5. Construction of double-stranded metallosupramolecular polymers with a controlled helicity by combination of salt bridges and metal coordination.

    Science.gov (United States)

    Ikeda, Masato; Tanaka, Yoshie; Hasegawa, Takashi; Furusho, Yoshio; Yashima, Eiji

    2006-05-31

    We describe the construction of the first double-stranded metallosupramolecular helical polymers. We designed and synthesized a supramolecular duplex comprised of complementary m-terphenyl-based strands bearing a chiral amidine or achiral carboxylic acid together with two pyridine groups at the four ends. Supramolecular polymerization of the duplex with cis-PtPh2(DMSO)2 in 1,1,2,2-tetrachloroethane produced the double-stranded metallosupramolecular polymer with a controlled helicity of which the two complementary metallostrands are intertwined through the amidinium-carboxylate salt bridges. The structures and hydrodynamic dimensions of the metallosupramolecular polymers were characterized by 1H NMR, diffusion-ordered NMR, dynamic light scattering, absorption, and CD measurements. The polymeric structure was also visualized by atomic force microscopy.

  6. Fabrication of porous polymer microparticles with tunable pore size and density through the combination of phase separation and emulsion-solvent evaporation approach

    Science.gov (United States)

    Liu, Shanqin; Cai, Mingle; Deng, Renhua; Wang, Jianying; Liang, Ruijing; Zhu, Jintao

    2014-02-01

    A facile and versatile route to prepare porous polymer microparticles with tunable pore size and density through the combination of phase separation and emulsion-solvent evaporation method is demonstrated. When volatile organic solvent ( e.g., chloroform) diffuses through the aqueous phase containing poly(vinyl alcohol) (PVA) and evaporates, n-hexadecane (HD) and polystyrene (PS) in oil-in-water emulsion droplets occur to phase separate due to the incompatibility between PS and HD, ultimately yielding microparticles with porous structures. Interestingly, density of the pores (pore number) on the shell of microparticles can be tailored from one to hundreds by simply varying the HD concentration and/ or the rate of solvent evaporation. Moreover, this versatile approach for preparing porous microparticles with tunable pore size and density can be applied to other types of hydrophobic polymers, organic solvents, and alkanes, which will find potential applications in the fields of pharmaceutical, catalyst carrier, separation, and diagnostics.

  7. Microgel polymer composite fibres

    OpenAIRE

    Kehren, Dominic

    2014-01-01

    In this thesis some novel ideas and advancements in the field of polymer composite fibres, specifically microgel-based polymer composite fibres have been achieved. The main task was to investigate and understand the electrospinning process of microgels and polymers and the interplay of parameter influences, in order to fabricate reproducible and continuously homogenous composite fibres. The main aim was to fabricate a composite material which combines the special properties of polymer fibres ...

  8. Selective extraction and determination of chlorogenic acids as combined quality markers in herbal medicines using molecularly imprinted polymers based on a mimic template.

    Science.gov (United States)

    Ji, Wenhua; Zhang, Mingming; Yan, Huijiao; Zhao, Hengqiang; Mu, Yan; Guo, Lanping; Wang, Xiao

    2017-12-01

    We describe a solid-phase extraction adsorbent based on molecularly imprinted polymers (MIPs), prepared with use of a mimic template. The MIPs were used for the selective extraction and determination of three chlorogenic acids as combined quality markers for Lonicera japonica and Lianhua qingwen granules. The morphologies and surface groups of the MIPs were assessed by scanning electron microscopy, Brunauer-Emmett-Teller surface area analysis, and Fourier transform infrared spectroscopy. The adsorption isotherms, kinetics, and selectivity of the MIPs were systematically compared with those of non-molecularly imprinted polymers. The MIPs showed high selectivity toward three structurally similar chlorogenic acids (chlorogenic acid, cryptochlorogenic acid, and neochlorogenic acid). A procedure using molecularly imprinted solid-phase extraction coupled with high-performance liquid chromatography was established for the determination of three chlorogenic acids from Lonicera japonica and Lianhua qingwen granules. The recoveries of the chlorogenic acids ranged from 93.1% to 101.4%. The limits of detection and limits of quantification for the three chlorogenic acids were 0.003 mg g -1 and 0.01 mg g -1 , respectively. The newly developed method is thus a promising technique for the enrichment and determination of chlorogenic acids from herbal medicines. Graphical Abstract Mimic molecularly imprinted polymers for the selective extraction of chlorogenic acids.

  9. Bio-Inspired Fluoro-polydopamine Meets Barium Titanate Nanowires: A Perfect Combination to Enhance Energy Storage Capability of Polymer Nanocomposites.

    Science.gov (United States)

    Wang, Guanyao; Huang, Xingyi; Jiang, Pingkai

    2017-03-01

    Rapid evolution of energy storage devices expedites the development of high-energy-density materials with excellent flexibility and easy processing. The search for such materials has triggered the development of high-dielectric-constant (high-k) polymer nanocomposites. However, the enhancement of k usually suffers from sharp reduction of breakdown strength, which is detrimental to substantial increase of energy storage capability. Herein, the combination of bio-inspired fluoro-polydopamine functionalized BaTiO 3 nanowires (NWs) and a fluoropolymer matrix offers a new thought to prepare polymer nanocomposites. The elaborate functionalization of BaTiO 3 NWs with fluoro-polydopamine has guaranteed both the increase of k and the maintenance of breakdown strength, resulting in significantly enhanced energy storage capability. The nanocomposite with 5 vol % functionalized BaTiO 3 NWs discharges an ultrahigh energy density of 12.87 J cm -3 at a relatively low electric field of 480 MV m -1 , more than three and a half times that of biaxial-oriented polypropylene (BOPP, 3.56 J cm -3 at 600 MV m -1 ). This superior energy storage capability seems to rival or exceed some reported advanced nanoceramics-based materials at 500 MV m -1 . This new strategy permits insights into the construction of polymer nanocomposites with high energy storage capability.

  10. Fabrication of combined-scale nano- and microfluidic polymer systems using a multilevel dry etching, electroplating and molding process

    DEFF Research Database (Denmark)

    Tanzi, Simone; Østergaard, Peter Friis; Matteucci, Marco

    2012-01-01

    Microfabricated single-cell capture and DNA stretching devices have been produced by injection molding. The fabrication scheme employed deep reactive ion etching in a silicon substrate, electroplating in nickel and molding in cyclic olefin polymer. This work proposes technical solutions to fabric......Microfabricated single-cell capture and DNA stretching devices have been produced by injection molding. The fabrication scheme employed deep reactive ion etching in a silicon substrate, electroplating in nickel and molding in cyclic olefin polymer. This work proposes technical solutions...... to fabrication challenges associated with chip sealing and demolding of polymer high-volume replication methods. UV-assisted thermal bonding was found to ensure a strong seal of the microstructures in the molded part without altering the geometry of the channels. In the DNA stretching device, a low aspect ratio...... nanoslit (1/200) connecting two larger micro-channels was used to stretch a 168.5 kbp DNA molecule, while in the other device single-HeLa cells were captured against a micro-aperture connecting two larger microfluidic channels. Different dry etching processes have been investigated for the master...

  11. Photocatalytic oxygen evolution from low-bandgap conjugated microporous polymer nanosheets: a combined first-principles calculation and experimental study.

    Science.gov (United States)

    Wang, Lei; Wan, Yangyang; Ding, Yanjun; Niu, Yuchen; Xiong, Yujie; Wu, Xiaojun; Xu, Hangxun

    2017-03-23

    Nanostructured semiconducting polymers have emerged as a very promising class of metal-free photocatalytic materials for solar water splitting. However, they generally exhibit low efficiency and lack the ability to utilize long-wavelength photons in a photocatalytic oxygen evolution reaction (OER). Here, based on first-principles calculations, we reveal that the two-dimensional (2D) aza-fused conjugated microporous polymer (aza-CMP) with a honeycomb network is a semiconductor with novel layer-dependent electronic properties. The bandgap of the as-synthesized aza-CMP nanosheets is measured to be 1.22 eV, suggesting that they can effectively boost light absorption in the visible and near infrared (NIR) region. More importantly, aza-CMP also possesses a valence band margin suitable for a photocatalytic OER. Taking advantage of the 2D layered nanostructure, we further show that the exfoliated ultrathin aza-CMP nanosheets can exhibit a three-fold enhancement in the photocatalytic OER. After deposition of a Co(OH) 2 cocatalyst, the hybrid Co(OH) 2 /aza-CMP photocatalyst exhibits a markedly improved performance for photocatalytic O 2 evolution. Furthermore, first-principles calculations reveal that the photocatalytic O 2 evolution reaction is energetically feasible for aza-CMP nanosheets under visible light irradiation. Our findings reveal that nanostructured polymers hold great potential for photocatalytic applications with efficient solar energy utilization.

  12. Electrochromic properties of multicolored novel polymer synthesized via combination of benzotriazole and N-functionalized 2,5-di(2-thienyl)-1H-pyrrole units

    International Nuclear Information System (INIS)

    Rende, Eda; Kilic, Cihan E.; Udum, Yasemin Arslan; Toffoli, Daniele; Toppare, Levent

    2014-01-01

    Synthesis of new conducting polymers is desired since their electrochemical and optical properties enable them to be used as active layers in many device applications. Benzotriazole and N-functionalized 2,5-di(2-thienyl)-1H-pyrrole (SNS Series) containing polymers showed very promising results as electrochromic materials. In order to observe the effect of the combination of these two units, three new monomers; 2-(6-(2,5-bis(5-methylthiophen-2-yl)-1H-pyrrol-1-yl)hexyl)-4,7-di (thiophen-2-yl)-2H benzo[d][1,2,3]triazole (M1), 2-(6-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)hexyl)-4,7-di(thiophen-2-yl) -2H-benzo[d][1,2,3]triazole (M2) and 2-(6-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)hexyl)-4,7-bis (5-methylthiophen-2-yl)-2H-benzo[d][1,2,3]triazole (M3) were synthesized. To better characterize the electronic and spectroscopic properties of the monomers, density functional theory (DFT) and its time-dependent generalization (TD-DFT) were used to calculate their vertical ionization potentials, vertical electron affinity and to simulate and interpret their infrared and UV-vis spectra. The monomers were electrochemically polymerized and the resultant polymers were characterized with cyclic voltammetry and UV-vis-NIR spectroscopy techniques. An electrochromic device was constructed with electrochemical polymer of M2. The device switched between red and blue colors and showed exceptional optical memory

  13. Antimocrobial Polymer

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, William F. (Utica, OH); Huang, Zhi-Heng (Walnut Creek, CA); Wright, Stacy C. (Columbus, GA)

    2005-09-06

    A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from quaternary ammonium compounds, gentian violet compounds, substituted or unsubstituted phenols, biguanide compounds, iodine compounds, and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A)3P wherein A is hydroxyalkyl; and the antimicrobial agent is chlorhexidine, dimethylchlorophenol, cetyl pyridinium chloride, gentian violet, triclosan, thymol, iodine, and mixtures thereof.

  14. Combined novel methods for the determination of the humidification conditions of polymer electrolyte fuel cells; Kombination neuer Methoden zur Bestimmung des Wasserhaushaltes von Polymer-Elektrolyt-Brennstoffzellen

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, Robert Martin

    2011-05-02

    The water management is one of the key factors for the performance of a low temperature PEM fuel cell. With respect to the optimization of the fuel cell operation it is important to detect and differentiate water in the membrane, in the gas diffusion layer (GDL) and excess water in the flow field channel. The water content of each component influences the performance in different ways and adapted operation modes have to be kept. This work entitled 'Combined novel methods for the determination of the humidification conditions of PEM fuel cells' provides techniques and guidelines for fuel cell operation and will conclude in a straightforward control and operation strategy. Based on a combination of electrochemical impedance spectroscopy (EIS), locally resolved current distribution measurements and neutron radiography an informative basis for the determination of the water content of an operating PEM fuel cell is created. Special attention has been paid to the reproducibility and comparability in order to set up a consistent investigation and control strategy. (orig.)

  15. Combined TGA-MS kinetic analysis of multistep processes. Thermal decomposition and ceramification of polysilazane and polysiloxane preceramic polymers.

    Science.gov (United States)

    García-Garrido, C; Sánchez-Jiménez, P E; Pérez-Maqueda, L A; Perejón, A; Criado, José M

    2016-10-26

    The polymer-to-ceramic transformation kinetics of two widely employed ceramic precursors, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane (TTCS) and polyureamethylvinylsilazane (CERASET), have been investigated using coupled thermogravimetry and mass spectrometry (TG-MS), Raman, XRD and FTIR. The thermally induced decomposition of the pre-ceramic polymer is the critical step in the synthesis of polymer derived ceramics (PDCs) and accurate kinetic modeling is key to attaining a complete understanding of the underlying process and to attempt any behavior predictions. However, obtaining a precise kinetic description of processes of such complexity, consisting of several largely overlapping physico-chemical processes comprising the cleavage of the starting polymeric network and the release of organic moieties, is extremely difficult. Here, by using the evolved gases detected by MS as a guide it has been possible to determine the number of steps that compose the overall process, which was subsequently resolved using a semiempirical deconvolution method based on the Frasier-Suzuki function. Such a function is more appropriate that the more usual Gaussian or Lorentzian functions since it takes into account the intrinsic asymmetry of kinetic curves. Then, the kinetic parameters of each constituent step were independently determined using both model-free and model-fitting procedures, and it was found that the processes obey mostly diffusion models which can be attributed to the diffusion of the released gases through the solid matrix. The validity of the obtained kinetic parameters was tested not only by the successful reconstruction of the original experimental curves, but also by predicting the kinetic curves of the overall processes yielded by different thermal schedules and by a mixed TTCS-CERASET precursor.

  16. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  17. The effect of polymer matrices on the thermal hazard properties of RDX-based PBXs by using model-free and combined kinetic analysis.

    Science.gov (United States)

    Yan, Qi-Long; Zeman, Svatopluk; Sánchez Jiménez, P E; Zhao, Feng-Qi; Pérez-Maqueda, L A; Málek, Jiří

    2014-04-30

    In this paper, the decomposition reaction models and thermal hazard properties of 1,3,5-trinitro-1,3,5-triazinane (RDX) and its PBXs bonded by Formex P1, Semtex 1A, C4, Viton A and Fluorel polymer matrices have been investigated based on isoconversional and combined kinetic analysis methods. The established kinetic triplets are used to predict the constant decomposition rate temperature profiles, the critical radius for thermal explosion and isothermal behavior at a temperature of 82°C. It has been found that the effect of the polymer matrices on the decomposition mechanism of RDX is significant resulting in very different reaction models. The Formex P1, Semtex and C4 could make decomposition process of RDX follow a phase boundary controlled reaction mechanism, whereas the Viton A and Fluorel make its reaction model shifts to a two dimensional Avrami-Erofeev nucleation and growth model. According to isothermal simulations, the threshold cook-off time until loss of functionality at 82°C for RDX-C4 and RDX-FM is less than 500 days, while it is more than 700 days for the others. Unlike simulated isothermal curves, when considering the charge properties and heat of decomposition, RDX-FM and RDX-C4 are better than RDX-SE in storage safety at arbitrary surrounding temperature. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Assessment of a new method for the analysis of decomposition gases of polymers by a combining thermogravimetric solid-phase extraction and thermal desorption gas chromatography mass spectrometry.

    Science.gov (United States)

    Duemichen, E; Braun, U; Senz, R; Fabian, G; Sturm, H

    2014-08-08

    For analysis of the gaseous thermal decomposition products of polymers, the common techniques are thermogravimetry, combined with Fourier transformed infrared spectroscopy (TGA-FTIR) and mass spectrometry (TGA-MS). These methods offer a simple approach to the decomposition mechanism, especially for small decomposition molecules. Complex spectra of gaseous mixtures are very often hard to identify because of overlapping signals. In this paper a new method is described to adsorb the decomposition products during controlled conditions in TGA on solid-phase extraction (SPE) material: twisters. Subsequently the twisters were analysed with thermal desorption gas chromatography mass spectrometry (TDS-GC-MS), which allows the decomposition products to be separated and identified using an MS library. The thermoplastics polyamide 66 (PA 66) and polybutylene terephthalate (PBT) were used as example polymers. The influence of the sample mass and of the purge gas flow during the decomposition process was investigated in TGA. The advantages and limitations of the method were presented in comparison to the common analysis techniques, TGA-FTIR and TGA-MS. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Conducting polymer 3D microelectrodes

    DEFF Research Database (Denmark)

    Sasso, Luigi; Vazquez, Patricia; Vedarethinam, Indumathi

    2010-01-01

    Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained...... showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared...

  20. A short review of radiation-induced raft-mediated graft copolymerization: A powerful combination for modifying the surface properties of polymers in a controlled manner

    Science.gov (United States)

    Barsbay, Murat; Güven, Olgun

    2009-12-01

    Surface grafting of polymeric materials is attracting increasing attention as it enables the preparation of new materials from known and commercially available polymers having desirable bulk properties such as thermal stability, elasticity, permeability, etc., in conjunction with advantageous newly tailored surface properties such as biocompatibility, biomimicry, adhesion, etc. Ionizing radiation, particularly γ radiation is one of the most powerful tools for preparing graft copolymers as it generates radicals on most substrates. With the advent of living free-radical polymerization techniques, application of γ radiation has been extended to a new era of grafting; grafting in a controlled manner to achieve surfaces with tailored and well-defined properties. This report presents the current use of γ radiation in living free-radical polymerization and highlights the use of both techniques together as a combination to present an advance in the ability to prepare surfaces with desired, tunable and well-defined properties.

  1. A short review of radiation-induced raft-mediated graft copolymerization: A powerful combination for modifying the surface properties of polymers in a controlled manner

    Energy Technology Data Exchange (ETDEWEB)

    Barsbay, Murat [Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara (Turkey)], E-mail: mbarsbay@hacettepe.edu.tr; Gueven, Olgun [Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara (Turkey)], E-mail: guven@hacettepe.edu.tr

    2009-12-15

    Surface grafting of polymeric materials is attracting increasing attention as it enables the preparation of new materials from known and commercially available polymers having desirable bulk properties such as thermal stability, elasticity, permeability, etc., in conjunction with advantageous newly tailored surface properties such as biocompatibility, biomimicry, adhesion, etc. Ionizing radiation, particularly {gamma} radiation is one of the most powerful tools for preparing graft copolymers as it generates radicals on most substrates. With the advent of living free-radical polymerization techniques, application of {gamma} radiation has been extended to a new era of grafting; grafting in a controlled manner to achieve surfaces with tailored and well-defined properties. This report presents the current use of {gamma} radiation in living free-radical polymerization and highlights the use of both techniques together as a combination to present an advance in the ability to prepare surfaces with desired, tunable and well-defined properties.

  2. A short review of radiation-induced raft-mediated graft copolymerization: A powerful combination for modifying the surface properties of polymers in a controlled manner

    International Nuclear Information System (INIS)

    Barsbay, Murat; Gueven, Olgun

    2009-01-01

    Surface grafting of polymeric materials is attracting increasing attention as it enables the preparation of new materials from known and commercially available polymers having desirable bulk properties such as thermal stability, elasticity, permeability, etc., in conjunction with advantageous newly tailored surface properties such as biocompatibility, biomimicry, adhesion, etc. Ionizing radiation, particularly γ radiation is one of the most powerful tools for preparing graft copolymers as it generates radicals on most substrates. With the advent of living free-radical polymerization techniques, application of γ radiation has been extended to a new era of grafting; grafting in a controlled manner to achieve surfaces with tailored and well-defined properties. This report presents the current use of γ radiation in living free-radical polymerization and highlights the use of both techniques together as a combination to present an advance in the ability to prepare surfaces with desired, tunable and well-defined properties.

  3. A novel restricted access material combined to molecularly imprinted polymers for selective solid-phase extraction and high performance liquid chromatography determination of 2-methoxyestradiol in plasma samples.

    Science.gov (United States)

    Du, Bin; Qu, Tiantian; Chen, Zheng; Cao, Xiaohui; Han, Shuping; Shen, Guopeng; Wang, Lei

    2014-11-01

    A feasibility study was performed in order to ensure the possibilities in using a restricted access material combined to molecularly imprinted polymers (RAM-MIP) as sorbent material in solid phase extraction (SPE) for clean-up of 2-methoxyestradiol (2-ME) from plasma samples. The MIP with hydrophilic external layer was designed by precipitation polymerization. The polymer was characterized by thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The use of analogs of 2-ME as templates, in combination with a chromatographic separation of the analytes in the sample, overcame the problem of the template bleeding. To demonstrate the property of the RAM-MIP obtained, a comparison of commercially available C18 SPE was performed. The results showed that the RAM-MISPE recoveries were significantly higher than that of C18 SPE for 2-ME in trace concentration. During the extraction process, 2-ME was sufficiently cleaned for further chromatographic analysis with no interferences from template leakage and matrix. Good linearity was obtained from 0.06 to 20 μg mL(-1) with the correlation coefficient r>0.9991. The coefficient of variation of the inter-assay precision was less than 11.9%. The recoveries of 2-ME in rat plasma at three spiked levels were in the range of 99.10-101.00%. Based on the analytical validation results, the proposed method (RAM-MIP off-line SPE/HPLC) can be a useful tool to determine 2-ME in rat plasma samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Precursor polymer compositions comprising polybenzimidazole

    Energy Technology Data Exchange (ETDEWEB)

    Klaehn, John R.; Peterson, Eric S.; Orme, Christopher J.

    2015-07-14

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  5. Biodegradable Polymers

    OpenAIRE

    Vroman, Isabelle; Tighzert, Lan

    2009-01-01

    Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources) or from biological resources (renewable resources). In general natural polymers offer fewer advantages than synthetic polymers. ...

  6. Light-controlled drug releasing polymer films combining LbL self-assembly and host-guest interactions

    Directory of Open Access Journals (Sweden)

    J. Li

    2014-03-01

    Full Text Available By combining LbL (layer-by-layer self-assembly approach and host-guest interactions, a unique multilayer film was constructed and employed for a light-controlled drug release system. The drug molecules can be loaded and released into the resulting polyelectrolyte multilayers containing azobenzene (Azo function groups by using the irradiation of visible light and UV light alternately. The photo-sensitivity of the multilayer films was studied through UV-vis spectrum, fluorescence spectrum and confocal microscopy. The target molecules could be rapidly released from the multilayers after 300 W UV light irradiation for 20 minutes. Moreover, they could be readsorbed into the multilayers uniformly when illuminated under the 300 W visible light for 10 minutes confirmed by the observation of confocal microscopy, and the readsorption ratio exceeds 100% evidenced from UV–vis spectroscopy. After several cycles of the above-mentioned process, the multilayer films show good fatigue resistance. All these results indicate the photo-sensitivity and high-efficiency of the multilayer films, which have great potential in controlled drug delivery platform and biomedical applications.

  7. Solid phase microextraction of diclofenac using molecularly imprinted polymer sorbent in hollow fiber combined with fiber optic-linear array spectrophotometry

    Science.gov (United States)

    Pebdani, Arezou Amiri; Shabani, Ali Mohammad Haji; Dadfarnia, Shayessteh; Khodadoust, Saeid

    2015-08-01

    A simple solid phase microextraction method based on molecularly imprinted polymer sorbent in the hollow fiber (MIP-HF-SPME) combined with fiber optic-linear array spectrophotometer has been applied for the extraction and determination of diclofenac in environmental and biological samples. The effects of different parameters such as pH, times of extraction, type and volume of the organic solvent, stirring rate and donor phase volume on the extraction efficiency of the diclofenac were investigated and optimized. Under the optimal conditions, the calibration graph was linear (r2 = 0.998) in the range of 3.0-85.0 μg L-1 with a detection limit of 0.7 μg L-1 for preconcentration of 25.0 mL of the sample and the relative standard deviation (n = 6) less than 5%. This method was applied successfully for the extraction and determination of diclofenac in different matrices (water, urine and plasma) and accuracy was examined through the recovery experiments.

  8. Polymer monolithic capillary microextraction combined on-line with inductively coupled plasma MS for the determination of trace rare earth elements in biological samples.

    Science.gov (United States)

    Zhang, Lin; Chen, Beibei; He, Man; Hu, Bin

    2013-07-01

    A rapid and sensitive method based on polymer monolithic capillary microextraction combined on-line with microconcentric nebulization inductively coupled plasma MS has been developed for the determination of trace/ultratrace rare earth elements in biological samples. For this purpose, the iminodiacetic acid modified poly(glycidyl methacrylate-trimethylolpropane trimethacrylate) monolithic capillary was prepared and characterized by SEM and FTIR spectroscopy. Factors affecting the extraction efficiency, such as sample pH, sample flow rate, sample/eluent volume, and coexisting ions were investigated in detail. Under the optimal conditions, the LODs for rare earth elements were in the range of 0.08 (Er) to 0.97 ng/L (Nd) with a sampling frequency of 8.5 h(-1), and the RSDs were between 1.5% (Sm) and 7.4% (Nd) (c = 20 ng/L, n = 7). The proposed method was successfully applied to the analysis of trace/ultratrace rare earth elements in human urine and serum samples, and the recoveries for the spiked samples were in the range of 82-105%. The developed method was simple, rapid, sensitive, and favorable for the analysis of trace/ultratrace rare earth elements in biological samples with limited sample volume. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Polymer Nanocomposite Film with Metal Rich Surface Prepared by In Situ Single-Step Formation of Palladium Nanoparticles: An Interesting Way to Combine Specific Functional Properties

    Directory of Open Access Journals (Sweden)

    David Thompson

    2016-10-01

    Full Text Available This paper presents a continuous single-step route that permits preparation of a thermostable polymer/metal nanocomposite film and to combine different functional properties in a unique material. More precisely, palladium nanoparticles are in situ generated in a polyimide matrix thanks to a designed curing cycle which is applied to a polyamic acid/metal precursor solution cast on a glass plate. A metal-rich surface layer which is strongly bonded to the bulk film is formed in addition to homogeneously dispersed metal nanoparticles. This specific morphology leads to obtaining an optically reflective film. The metal nanoparticles act as gas diffusion barriers for helium, oxygen, and carbon dioxide; they induce a tortuosity effect which allows dividing the gas permeation coefficients by a factor near to 2 with respect to the neat polyimide matrix. Moreover, the ability of the in situ synthesized palladium nanoparticles to entrap hydrogen is evidenced. The nanocomposite film properties can be modulated as a function of the location of the film metal-rich surface with respect to the hydrogen feed. The synthesized nanocomposite could represent a major interest for a wide variety of applications, from specific coatings for aerospace or automotive industry, to catalysis applications or sensors.

  10. Solid phase microextraction of diclofenac using molecularly imprinted polymer sorbent in hollow fiber combined with fiber optic-linear array spectrophotometry.

    Science.gov (United States)

    Pebdani, Arezou Amiri; Shabani, Ali Mohammad Haji; Dadfarnia, Shayessteh; Khodadoust, Saeid

    2015-08-05

    A simple solid phase microextraction method based on molecularly imprinted polymer sorbent in the hollow fiber (MIP-HF-SPME) combined with fiber optic-linear array spectrophotometer has been applied for the extraction and determination of diclofenac in environmental and biological samples. The effects of different parameters such as pH, times of extraction, type and volume of the organic solvent, stirring rate and donor phase volume on the extraction efficiency of the diclofenac were investigated and optimized. Under the optimal conditions, the calibration graph was linear (r(2)=0.998) in the range of 3.0-85.0 μg L(-1) with a detection limit of 0.7 μg L(-1) for preconcentration of 25.0 mL of the sample and the relative standard deviation (n=6) less than 5%. This method was applied successfully for the extraction and determination of diclofenac in different matrices (water, urine and plasma) and accuracy was examined through the recovery experiments. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Multiple-level porous polymer monoliths with interconnected cellular topology prepared by combining hard sphere and emulsion templating for use in bone tissue engineering

    Czech Academy of Sciences Publication Activity Database

    Paljevac, M.; Gradišnik, L.; Lipovšek, S.; Maver, U.; Kotek, Jiří; Krajnc, P.

    2018-01-01

    Roč. 18, č. 2 (2018), s. 1-8, č. článku 1700306. ISSN 1616-5187 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : bone tissue engineering * hierarchical materials * polymer scaffolds Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.238, year: 2016

  12. Safety and Efficacy of Nucleic Acid Polymers in Monotherapy and Combined with Immunotherapy in Treatment-Naive Bangladeshi Patients with HBeAg+ Chronic Hepatitis B Infection.

    Directory of Open Access Journals (Sweden)

    Mamun Al-Mahtab

    Full Text Available Previous in vivo studies have suggested that nucleic acid polymers (NAPs may reduce circulating levels of HBsAg in the blood by blocking its release from infected hepatocytes and that this effect may have clinical benefit. NAP treatment, was evaluated in two clinical studies in patients with HBeAg positive chronic HBV infection. The REP 101 study examined REP 2055 monotherapy in 8 patients and the REP 102 study examined REP 2139-Ca, in monotherapy in 12 patients, 9 of which transitioned to short term combined treatment with pegylated interferon alpha 2a or thymosin alpha 1. In both studies NAP monotherapy was accompanied by 2-7 log reductions of serum HBsAg, 3-9 log reductions in serum HBV DNA and the appearance of serum anti-HBsAg antibodies (10-1712 mIU / ml. Eight of the 9 patients transitioning to combined treatment with immunotherapy (pegylated interferon or thymosin alpha 1 in the REP 102 study experienced HBsAg loss and all 9 patients experienced substantial increases in serum anti-HBsAg antibody titers before withdrawal of therapy. For 52 weeks after removal of REP 2055 therapy, rebound of serum viremia (HBV DNA > 1000 copies / ml, HBsAg > 1IU / ml was not observed in 3 / 8 patients. Suppression of serum virema was further maintained for 290 and 231 weeks in 2 of these patients. After withdrawal of all therapy in the 9 patients that transitioned to combination therapy in the REP 102 study, 8 patients achieved HBV DNA < 116 copies / ml after treatment withdrawal. Viral rebound occurred over a period of 12 to 123 weeks in 7 patients but was still absent in two patients at 135 and 137 weeks of follow-up. Administration tolerability issues observed with REP 2055 were rare with REP 2139-Ca but REP 2139-Ca therapy was accompanied by hair loss, dysphagia and dysgeusia which were considered related to heavy metal exposure endemic at the trial site. These preliminary studies suggest that NAP can elicit important antiviral responses during

  13. Safety and Efficacy of Nucleic Acid Polymers in Monotherapy and Combined with Immunotherapy in Treatment-Naive Bangladeshi Patients with HBeAg+ Chronic Hepatitis B Infection.

    Science.gov (United States)

    Al-Mahtab, Mamun; Bazinet, Michel; Vaillant, Andrew

    2016-01-01

    Previous in vivo studies have suggested that nucleic acid polymers (NAPs) may reduce circulating levels of HBsAg in the blood by blocking its release from infected hepatocytes and that this effect may have clinical benefit. NAP treatment, was evaluated in two clinical studies in patients with HBeAg positive chronic HBV infection. The REP 101 study examined REP 2055 monotherapy in 8 patients and the REP 102 study examined REP 2139-Ca, in monotherapy in 12 patients, 9 of which transitioned to short term combined treatment with pegylated interferon alpha 2a or thymosin alpha 1. In both studies NAP monotherapy was accompanied by 2-7 log reductions of serum HBsAg, 3-9 log reductions in serum HBV DNA and the appearance of serum anti-HBsAg antibodies (10-1712 mIU / ml). Eight of the 9 patients transitioning to combined treatment with immunotherapy (pegylated interferon or thymosin alpha 1) in the REP 102 study experienced HBsAg loss and all 9 patients experienced substantial increases in serum anti-HBsAg antibody titers before withdrawal of therapy. For 52 weeks after removal of REP 2055 therapy, rebound of serum viremia (HBV DNA > 1000 copies / ml, HBsAg > 1IU / ml) was not observed in 3 / 8 patients. Suppression of serum virema was further maintained for 290 and 231 weeks in 2 of these patients. After withdrawal of all therapy in the 9 patients that transitioned to combination therapy in the REP 102 study, 8 patients achieved HBV DNA < 116 copies / ml after treatment withdrawal. Viral rebound occurred over a period of 12 to 123 weeks in 7 patients but was still absent in two patients at 135 and 137 weeks of follow-up. Administration tolerability issues observed with REP 2055 were rare with REP 2139-Ca but REP 2139-Ca therapy was accompanied by hair loss, dysphagia and dysgeusia which were considered related to heavy metal exposure endemic at the trial site. These preliminary studies suggest that NAP can elicit important antiviral responses during treatment which may

  14. Polymer electronics

    CERN Document Server

    Hsin-Fei, Meng

    2013-01-01

    Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

  15. IR absorption and reflectometric interference spectroscopy (RIfS) combined to a new sensing approach for gas analytes absorbed into thin polymer films

    Science.gov (United States)

    Leopold, Nicolae; Busche, Stefan; Gauglitz, Günter; Lendl, Bernhard

    2009-06-01

    Hydrophobic polymer layers (3 μm) were spin-coated on Si or Ge plates and placed in a flow through gas chamber. FTIR reflection spectra of the layers were recorded showing the characteristic IR absorption bands of the polymer and the interference pattern generated by layered structure of the polymer film. Upon exposure of the polymer layer to gaseous analytes enrichment in the polymer film occurred. This was evidenced by the appearance of analyte specific absorption particular in the mid-IR part of the spectrum, as well as by a shift in the interference pattern across the whole spectrum. Qualitative information concerning the analyte was accessible in the mid-IR part of the spectrum, whereas quantitative assessment was obtained from the interference pattern. Polyetherurethane, polydimethylsiloxane, Makrolon ® and polyisobutylene polymer layers were tested for such IR-RIfS measurements, whereas toluene, o-dichlorobenzene, m-xylene, ethyl acetate and cyclohexane were employed as analytes. There was no influence of water vapour neither on the IR absorptions nor the interference pattern as hydrophobic polymers were used.

  16. All Polymer Micropump

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen

    2008-01-01

    In this thesis an all polymer micropump, and the fabrication method required to fabricate this, are examined. Polymer microfluidic. devices are of major scientific interest because they can combine complicated chemical and biological analys~s in cheap and disposable devices. The electrode system...... in the micropump is based on the conducting polymer poly(3,4 ethylenedioxythiophene) (PEDOT). The majority of the work conducted was therefore aimed at developing methods for patterning and processing PEDOT. First a method was developed, where the conducting polymer PEDOT can be integrated into non...... of the substrate, the PEDOT is integrated into the non-conductive polymer. The result is a material that retains the good conductivity of PEDOT, but gains the mechanical stability of the substrate. The best results were obtained for PEDOTjPMMA. The new mechanically stable PEDOTjPMMA was micro-patterned using clean...

  17. New developments in thermally stable polymers

    Science.gov (United States)

    Hergenrother, Paul M.

    1991-01-01

    Advances in high-temperature polymers since 1985 are discussed with the emphasis on the chemistry. High-temperature polymers refer to materials that exhibit glass-transition temperatures greater than 200 C and have the chemical structure expected to provide high thermooxidative stability. Specific polymers or series of polymers were selected to show how the chemical structure influences certain properties. Poly(arylene ethers) and polyimides are the two principal families of polymers discussed. Recent work on poly(arylene ethers) has concentrated on incorporating heterocyclic units within the polymer backbone. Recent polyimide work has centered on the synthesis of new polymers from novel monomers, several containing the trifluoromethyl group strategically located on the molecule. Various members in each of these polymer families display a unique combination of properties, heretofore unattainable. Other families of polymers are also briefly discussed with a polymer from an AB maleimidobenzocyclobutene exhibiting an especially attractive combination of properties.

  18. Evaluating the potential of thermal read-out techniques combined with molecularly imprinted polymers for the sensing of low-weight organic molecules.

    Science.gov (United States)

    van Grinsven, B; Betlem, K; Cleij, T J; Banks, C E; Peeters, M

    2017-01-01

    In recent years, there has been a tremendous increase in the papers published on synthetic recognition elements. Molecularly imprinted polymers (MIPs), also referred to as "man-made mimics" of antibodies, are able to rebind their template molecules with high affinity. Advantages compared with those of natural receptors include their excellent thermal and chemical stability, low cost, and ease of the production process. However, their use in commercial biosensors is limited owing to the difficulty to incorporate MIPs into suitable sensing platforms and traditional detection techniques, such as chromatography, that require bulky and sophisticated equipment. In this review, we evaluate the potential to use MIPs combined with thermal read-out for the detection of low-weight organic molecules. We discuss thermal methods to study MIP-template complexation and to determine neurotransmitters concentrations. In particular, we highlight the heat-transfer method, a recent technique that is straightforward and low cost and requires minimal instrumentation. Until now, sample preparation involves a 2-step process, making it time-consuming, and measuring biological samples is difficult owing to the noise in the signal. Different sample preparation methods are discussed, and it will be demonstrated how this affects the thermal response. An outlook is given in novel methods that can simplify and speed up sample preparation. Finally, we show a novel thermal technique, which is based on the analysis of transport of thermal waves rather than evaluating the fixed heat-transfer resistance. Through applying the concept of thermal waves, signal-noise ratio is significantly increased, which results in lower detection limits and has potential for the study of biological samples. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Self-Healing in Nanoparticle-Reinforced Polymers and other Polymer Systems

    NARCIS (Netherlands)

    Picken, S.J.; Mookhoek, S.D.; Fischer, H.R.; Zwaag, S. van der

    2010-01-01

    This chapter aims at combining new insights in the field of (liquid encapsulated) self healing polymer systems as well as nanoparticle reinforced polymers to set the direction for the development of nanoparticle reinforced self healing polymers. In the case of self healing polymers the strategy is

  20. PHOTOREFRACTIVE POLYMERS

    NARCIS (Netherlands)

    Morichere, D; Malliaras, G.G; Krasnikov, V.V.; Bolink, H.J; Hadziioannou, G

    The use of polymers as photorefractive materials offers many advantages : flexibility in synthesis, doping, processing and low cost. The required functionalities responsible for photorefractivity, namely charge generation, transport, trapping and linear electrooptic effect are given in the polymer

  1. Polymer Nanocomposites

    Indian Academy of Sciences (India)

    polymer nanocompo- sites are used as advanced toner materials for high quality colour copiers and printers and as contrast agents in NMR analysis, memory devices. .... tions on polymer nanocomposite can thus pay rich dividends. Suggested Reading. [1] Metal-Polymer Nanocomposites Nicolais, Luigi(ed.) ; Carotenuto,.

  2. Photoluminescence in conjugated polymers

    International Nuclear Information System (INIS)

    Furst, J.E.; Laugesen, R.; Dastoor, P.; McNeill, C.

    2002-01-01

    Full text: Conjugated polymers combine the electronic and optical properties of semiconductors with the processability of polymers. They contain a sequence of alternate single and double carbon bonds so that the overlap of unhybridised p z orbitals creates a delocalised ρ system which gives semiconducting properties with p-bonding (valence) and p* -antibonding (conduction) bands. Photoluminesence (PL) in conjugated polymers results from the radiative decay of singlet excitons confined to a single chain. The present work is the first in a series of studies in our laboratory that will characterize the optical properties of conjugated polymers. The experiment involves the illumination of thin films of conjugated polymer with UV light (I=360 nm) and observing the subsequent fluorescence using a custom-built, fluorescence spectrometer. Photoluminesence spectra provide basic information about the structure of the polymer film. A typical spectrum is shown in the accompanying figure. The position of the first peak is related to the polymer chain length and resolved multiple vibronic peaks are an indication of film structure and morphology. We will also present results related to the optical degradation of these materials when exposed to air and UV light

  3. Two-Photon Photosensitizer-Polymer Conjugates for Combined Cancer Cell Death Induction and Two-Photon Fluorescence Imaging: Structure/Photodynamic Therapy Efficiency Relationship.

    Science.gov (United States)

    Cepraga, Cristina; Marotte, Sophie; Ben Daoud, Edna; Favier, Arnaud; Lanoë, Pierre-Henri; Monnereau, Cyrille; Baldeck, Patrice; Andraud, Chantal; Marvel, Jacqueline; Charreyre, Marie-Thérèse; Leverrier, Yann

    2017-12-11

    One of the challenges of photodynamic therapy is to increase the penetration depth of light irradiation in the tumor tissues. Although two-photon excitation strategies have been developed, the two-photon absorption cross sections of clinically used photosensitizers are generally low (below 300 GM). Besides, photosensitizers with high cross section values are often non-water-soluble. In this research work, a whole family of photosensitizer-polymer conjugates was synthesized via the covalent binding of a photosensitizer with a relatively high cross section along a biocompatible copolymer chain. The resulting photosensitizer-polymer conjugates were water-soluble and could be imaged in cellulo by two-photon microscopy thanks to their high two-photon absorption cross sections (up to 2600 GM in water, in the NIR range). In order to explore the structure/photodynamic activity relationship of such macromolecular photosensitizers, the influence of the polymer size, photosensitizer density, and presence of charges along the polymer backbone was investigated (neutral, anionic, cationic, and zwitterionic conjugates were compared). The macromolecular photosensitizers were not cytotoxic in the absence of light irradiation. Their kinetics of cellular uptake in the B16-F10 melanoma cell line were followed by flow cytometry over 24 h. The efficiency of cell death upon photoactivation was found to be highly correlated to the cellular uptake in turn correlated to the global charge of the macromolecular photosensitizer which appeared as the determining structural parameter.

  4. Binary Polymer Brushes of Strongly Immiscible Polymers.

    Science.gov (United States)

    Chu, Elza; Babar, Tashnia; Bruist, Michael F; Sidorenko, Alexander

    2015-06-17

    The phenomenon of microphase separation is an example of self-assembly in soft matter and has been observed in block copolymers (BCPs) and similar materials (i.e., supramolecular assemblies (SMAs) and homo/block copolymer blends (HBCs)). In this study, we use microphase separation to construct responsive polymer brushes that collapse to generate periodic surfaces. This is achieved by a chemical reaction between the minor block (10%, poly(4-vinylpyridine)) of the block copolymer and a substrate. The major block of polystyrene (PS) forms mosaic-like arrays of grafted patches that are 10-20 nm in size. Depending on the nature of the assembly (SMA, HBC, or neat BCP) and annealing method (exposure to vapors of different solvents or heating above the glass transition temperature), a range of "mosaic" brushes with different parameters can be obtained. Successive grafting of a secondary polymer (polyacrylamide, PAAm) results in the fabrication of binary polymer brushes (BPBs). Upon being exposed to specific selective solvents, BPBs may adopt different conformations. The surface tension and adhesion of the binary brush are governed by the polymer occupying the top stratum. The "mosaic" brush approach allows for a combination of strongly immiscible polymers in one brush. This facilitates substantial contrast in the surface properties upon switching, previously only possible for substrates composed of predetermined nanostructures. We also demonstrate a possible application of such PS/PAAm brushes in a tunable bioadhesion-bioadhesive (PS on top) or nonbioadhesive (PAAm on top) surface as revealed by Escherichia coli bacterial seeding.

  5. Preparation and evaluation of open-tubular capillary column combining a metal-organic framework and a brush-shaped polymer for liquid chromatography.

    Science.gov (United States)

    Chen, Kai; Zhang, Lingyi; Zhang, Weibing

    2018-03-30

    In this work, an open-tubular capillary liquid-phase column was prepared by modifying chain polymer on the inner surface of capillary and chemical bonding of metal organic frameworks, NH 2 -UiO-66, to the brushes of chain polymer (poly(glycidyl methacrylate)). Besides advantages of facial preparation and good permeability, the chain polymer effectively increases the modification amount of NH 2 -UiO-66 nanoparticles to increase the phase ratio of open-tubular capillary column and enhance the interactions with analytes. The results of scanning electron microscope energy-dispersive X-ray spectra indicated that NH 2 -UiO-66 nanoparticles were successfully bonded to the chain polymer. Because of the hydrophobic interaction and hydrogen bonding interaction between the analytes and the ligand of NH 2 -UiO-66, different analytes were well separated on the NH 2 -UiO-66-modified poly(glycidyl methacrylate) capillary (1.12 m × 25 μm id × 365 μm od) with the high absolute column efficiency reaching 121 477 plates, benefiting from an open-tubular column and low mass transfer resistance provided by polymer brush and metal-organic framework crystal. The relative standard deviations of the retention time for run-to-run, day-to-day, and column-to-column (n = 3) runs are below 4.28%, exhibiting good repeatability. Finally, the column was successfully applied to separation of flavonoids in licorice. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Polymer Chemistry

    Science.gov (United States)

    Williams, Martha; Roberson, Luke; Caraccio, Anne

    2010-01-01

    This viewgraph presentation describes new technologies in polymer and material chemistry that benefits NASA programs and missions. The topics include: 1) What are Polymers?; 2) History of Polymer Chemistry; 3) Composites/Materials Development at KSC; 4) Why Wiring; 5) Next Generation Wiring Materials; 6) Wire System Materials and Integration; 7) Self-Healing Wire Repair; 8) Smart Wiring Summary; 9) Fire and Polymers; 10) Aerogel Technology; 11) Aerogel Composites; 12) Aerogels for Oil Remediation; 13) KSC's Solution; 14) Chemochromic Hydrogen Sensors; 15) STS-130 and 131 Operations; 16) HyperPigment; 17) Antimicrobial Materials; 18) Conductive Inks Formulations for Multiple Applications; and 19) Testing and Processing Equipment.

  7. Star Polymers.

    Science.gov (United States)

    Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

    2016-06-22

    Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

  8. Polymer Electrolytes

    Science.gov (United States)

    Hallinan, Daniel T.; Balsara, Nitash P.

    2013-07-01

    This review article covers applications in which polymer electrolytes are used: lithium batteries, fuel cells, and water desalination. The ideas of electrochemical potential, salt activity, and ion transport are presented in the context of these applications. Potential is defined, and we show how a cell potential measurement can be used to ascertain salt activity. The transport parameters needed to fully specify a binary electrolyte (salt + solvent) are presented. We define five fundamentally different types of homogeneous electrolytes: type I (classical liquid electrolytes), type II (gel electrolytes), type III (dry polymer electrolytes), type IV (dry single-ion-conducting polymer electrolytes), and type V (solvated single-ion-conducting polymer electrolytes). Typical values of transport parameters are provided for all types of electrolytes. Comparison among the values provides insight into the transport mechanisms occurring in polymer electrolytes. It is desirable to decouple the mechanical properties of polymer electrolyte membranes from the ionic conductivity. One way to accomplish this is through the development of microphase-separated polymers, wherein one of the microphases conducts ions while the other enhances the mechanical rigidity of the heterogeneous polymer electrolyte. We cover all three types of conducting polymer electrolyte phases (types III, IV, and V). We present a simple framework that relates the transport parameters of heterogeneous electrolytes to homogeneous analogs. We conclude by discussing electrochemical stability of electrolytes and the effects of water contamination because of their relevance to applications such as lithium ion batteries.

  9. Integration of active and passive polymer optics

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Schøler, Mikkel; Kristensen, Anders

    2007-01-01

    We demonstrate a wafer scale fabrication process for integration of active and passive polymer optics: Polymer DFB lasers and waveguides. Polymer dye DFB lasers are fabricated by combined nanoimprint and photolithography (CNP). The CNP fabrication relies on an UV transparent stamp with nm sized...

  10. Electronic and Ionic Transport in Polymers.

    Science.gov (United States)

    1988-04-06

    as well as the parent polymers, have been elucidated via the combined use of FTIR and voltammetry. A manuscript detailing these results is in...Polymerization of ct,c’-Dibromo- xylene Isomer," J. Polym. Sci., Polym. Lett. Ed., in press. Papers Submitted for Publication Reynolds, J.R., Sundaresan, N.S

  11. Polymer chemistry (revised edition)

    International Nuclear Information System (INIS)

    Kim, Jae Mum

    1987-02-01

    This book deals with polymer chemistry, which is divided into fourteen chapters. The contents of this book are development of polymer chemistry, conception of polymer, measurement of polymer chemistry, conception of polymer, measurement of polymer, molecule structure of polymer, thermal prosperities of solid polymer, basic theory of polymerization, radical polymerization, ion polymerization, radical polymerization, copolymerization, polymerization by step-reaction, polymer reaction, crown polymer and inorganic polymer on classification and process of creation such as polymeric sulfur and carbon fiber.

  12. Polymer Directed Protein Assemblies

    Directory of Open Access Journals (Sweden)

    Patrick van Rijn

    2013-05-01

    Full Text Available Protein aggregation and protein self-assembly is an important occurrence in natural systems, and is in some form or other dictated by biopolymers. Very obvious influences of biopolymers on protein assemblies are, e.g., virus particles. Viruses are a multi-protein assembly of which the morphology is dictated by poly-nucleotides namely RNA or DNA. This “biopolymer” directs the proteins and imposes limitations on the structure like the length or diameter of the particle. Not only do these bionanoparticles use polymer-directed self-assembly, also processes like amyloid formation are in a way a result of directed protein assembly by partial unfolded/misfolded biopolymers namely, polypeptides. The combination of proteins and synthetic polymers, inspired by the natural processes, are therefore regarded as a highly promising area of research. Directed protein assembly is versatile with respect to the possible interactions which brings together the protein and polymer, e.g., electrostatic, v.d. Waals forces or covalent conjugation, and possible combinations are numerous due to the large amounts of different polymers and proteins available. The protein-polymer interacting behavior and overall morphology is envisioned to aid in clarifying protein-protein interactions and are thought to entail some interesting new functions and properties which will ultimately lead to novel bio-hybrid materials.

  13. Multifunctional Polymer Nanocomposites

    Science.gov (United States)

    Galaska, Alexandra Maria; Song, Haixiang; Guo, Zhanhu

    With more awareness of energy conversion/storage and saving, different strategies have been developed to utilize the sustainable and renewable energy. Introducing nanoscale fillers can make inert polymer matrix possess unique properties to satisfy certain functions. For example, alumina nanoparticles have strengthened the weak thermosetting polymers. A combined mixture of carbon nanofibers and magnetite nanoparticles have made the inert epoxy sensitive for magnetic field for sensing applications. Introducing silica nanoparticles into conductive polymers such as polyaniline has enhanced the giant magnetoresistance behaviors. The introduced nanoparticles have made the transparent polymer have the electromagnetic interference (EMI) shielding function while reduce the density significantly. With the desired miniaturization, the materials combining different functionalities have become importantly interesting. In this talk, methodologies to prepare nanocomposites and their effects on the produced nanocomposites will be discussed. A variety of advanced polymer nanocomposites will be introduced. Unique properties including mechanical, electrical, magnetoresistance etc. and the applications for environmental remediation, energy storage/saving, fire retardancy, electromagnetic interference shielding, and electronic devices will be presented.

  14. Polymer Nanocomposites

    Indian Academy of Sciences (India)

    thane, PVC, polyesters, polystyrene and polypropylene. Also, some biocompatible polymers like PLA, poly (E-caprolactone) to mention a few, have been synthesized by varying methods and with different clay loadings (%by weight). The hydrophobicity /hydrophilicity ofthe polymer affects its dispersion in the clay.

  15. The structure of polymer carriers controls the efficacy of the experimental combination treatment of tumors with HPMA copolymer conjugates carrying doxorubicin and docetaxel

    Czech Academy of Sciences Publication Activity Database

    Šírová, Milada; Strohalm, Jiří; Chytil, Petr; Lidický, Ondřej; Tomala, Jakub; Říhová, Blanka; Etrych, Tomáš

    2017-01-01

    Roč. 246, JAN 28 (2017), s. 1-11 ISSN 0168-3659 R&D Projects: GA ČR(CZ) GA14-12742S; GA ČR(CZ) GA15-02986S; GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109; GA MZd(CZ) NV16-28600A; GA ČR(CZ) GAP301/12/1254 Institutional support: RVO:61388971 ; RVO:61389013 Keywords : Drug delivery * HPMA * Doxorubicin Subject RIV: EC - Immunology; CD - Macromolecular Chemistry (UMCH-V) OBOR OECD: Immunology; Polymer science (UMCH-V) Impact factor: 7.786, year: 2016

  16. Safety and Efficacy of Nucleic Acid Polymers in Monotherapy and Combined with Immunotherapy in Treatment-Naive Bangladeshi Patients with HBeAg+ Chronic Hepatitis B Infection

    OpenAIRE

    Al-Mahtab, Mamun; Bazinet, Michel; Vaillant, Andrew

    2016-01-01

    Previous in vivo studies have suggested that nucleic acid polymers (NAPs) may reduce circulating levels of HBsAg in the blood by blocking its release from infected hepatocytes and that this effect may have clinical benefit. NAP treatment, was evaluated in two clinical studies in patients with HBeAg positive chronic HBV infection. The REP 101 study examined REP 2055 monotherapy in 8 patients and the REP 102 study examined REP 2139-Ca, in monotherapy in 12 patients, 9 of which transitioned to s...

  17. Polymers and colloids

    Energy Technology Data Exchange (ETDEWEB)

    Schurtenberger, P. [ETH Zurich, Inst. fuer Polymere, Zurich (Switzerland)

    1996-11-01

    A wealth of structural information from colloid and polymer solutions on a large range of length scales can be obtained using small angle neutron scattering (SANS) experiments. After a general introduction to the field of soft condensed matter, I shall give a few selected examples on how SANS combined with suitable contrast variation schemes can be used to extract information on the size and conformation of polymer coils in solution and in the melt, and on the local structure and flexibility of polymerlike micelles and microemulsions. (author) 8 figs., tabs., 44 refs.

  18. Combination of computational methods, adsorption isotherms and selectivity tests for the conception of a mixed non-covalent-semi-covalent molecularly imprinted polymer of vanillin.

    Science.gov (United States)

    Puzio, Kinga; Delépée, Raphaël; Vidal, Richard; Agrofoglio, Luigi A

    2013-08-06

    A novel molecularly imprinted polymer (MIP) for vanillin was prepared by photo initiated polymerization in dichloromethane using a mixed semi-covalent and non-covalent imprinting strategy. Taking polymerisable syringaldehyde as "dummy" template, acrylamide was chosen as functional monomer on B3LYP/6-31+G(d,p) density functional theory computational method basis with counterpoise. The binding parameters for the recognition of vanillin on imprinted polymers were studied with three different isotherm models (Langmuir, bi-Langmuir and Langmuir-Freundlich) and compared. The results indicate an heterogeneity of binding sites. It was found and proved by DFT calculations that the specific binding of vanillin in the cavities is due to non-covalent interactions of the template with the hydroxyphenyl- and the amide-moieties. The binding geometry of vanillin in the MIP cavity was also modelled. The obtained MIP is highly specific for vanillin (with an imprinting factor of 7.4) and was successfully applied to the extraction of vanillin from vanilla pods, red wine spike with vanillin, natural and artificial vanilla sugar with a recovery of 80%. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Organometallic Polymers.

    Science.gov (United States)

    Carraher, Charles E., Jr.

    1981-01-01

    Reactions utilized to incorporate a metal-containing moiety into a polymer chain (addition, condensation, and coordination) are considered, emphasizing that these reactions also apply to smaller molecules. (JN)

  20. MICROBIOLIZATION WITH TRICHODERMA SPP., COMBINED OR NOT WITH POLYMER, ON THE HEALTH, GERMINATION AND VIGOR OF BLACK OATS AND BARLEY SEEDS

    Directory of Open Access Journals (Sweden)

    E. R. Baseggio

    2017-12-01

    Full Text Available The use of bioprotectors in the coating of seeds is increasing, and these become an alternative for the use of chemical fungicides. The aim of this work was to evaluate the use of Trichoderma spp., with or without polymerization, in the control of pathogens associated with black oats (Avena strigosa and barley (Hordeum vulgare seeds of the cultivars 'Comum' (black oats and BRS Cauê (barley, 2014 crop. After asepsis and dried of the seeds, the treatments were applied, using a dose of 5 mL of Trichoderma spp. kg-1 and 10 mL of seed polymer kg-1 of seeds. Sanity tests; germination; germination and emergency rate index; length of seedling (shoot and root; and fresh and dry weight were performed. The coating of oat and barley seeds with Trichoderma spp. was efficient in the control of pathogens, as well as increased the germination and development of the seedlings for both cultures evaluated.

  1. Functional mimicry of carboxypeptidase A by a combination of transition state stabilization and a defined orientation of catalytic moieties in molecularly imprinted polymers.

    Science.gov (United States)

    Liu, Jun-qiu; Wulff, Günter

    2008-06-25

    An artificial model for the natural enzyme carboxypeptidase A has been constructed by molecular imprinting in synthetic polymers. The tetrahedral transition state analogues (TSAs 4 and 5) for the carbonate hydrolysis have been designed as templates to allow incorporation of the main catalytic elements, an amidinium group and a Zn(2+) or Cu(2+) center, in a defined orientation in the transition state imprinted active site. The complexation of the functional monomer and the template in presence of Cu(2+) through stoichiometric noncovalent interaction was established on the basis of (1)H NMR studies and potentiometric titration. The Cu(2+) center was introduced into the imprinted cavity during polymerization or by substitution of Zn(2+) in Zn(2+) imprinted polymers. The direct introduction displayed obvious advantages in promoting catalytic efficiency. With substrates exhibiting a very similar structure to the template, an extraordinarily high enhancement of the rate of catalyzed to uncatalyzed reaction (k(cat)/k(uncat)) of 10(5)-fold was observed. If two amidinium moieties are introduced in proximity to one Cu(2+) center in the imprinted cavity by complexation of the functional monomer 3 with the template 5, the imprinted catalysts exhibited even higher activities and efficiencies for the carbonate hydrolysis with k(cat)/k(uncat) as high as 410,000. These are by far the highest values obtained for molecularly imprinted catalysts, and they are also considerably higher compared to catalytic antibodies. Our kinetic studies and competitive inhibition experiments with the TSA template showed a clear indication of a very efficient imprinting procedure. In addition, this demonstrates the important role of the transition state stabilization during the catalysis of this reaction.

  2. Polymers All Around You!

    Science.gov (United States)

    Gertz, Susan

    Background information on natural polymers, synthetic polymers, and the properties of polymers is presented as an introduction to this curriculum guide. Details are provided on the use of polymer products in consumer goods, polymer recycling, polymer densities, the making of a polymer such as GLUEP, polyvinyl alcohol, dissolving plastics, polymers…

  3. Polymer compositions, polymer films and methods and precursors for forming same

    Science.gov (United States)

    Klaehn, John R; Peterson, Eric S; Orme, Christopher J

    2013-09-24

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  4. Development and optimisation of a novel three-way extraction technique based on a combination of Soxhlet extraction, membrane assisted solvent extraction and a molecularly imprinted polymer using sludge polycyclic aromatic hydrocarbons as model compounds.

    Science.gov (United States)

    Ncube, Somandla; Lekoto, Goitsemang; Cukrowska, Ewa; Chimuka, Luke

    2018-02-01

    A novel technique that integrates extraction and clean-up into a single step format is reported as part of the search for new sample preparation techniques in the analysis of persistent organic pollutants from complex samples. This was achieved by combining the extraction efficiency of the Soxhlet extractor, the selectivity of a size exclusion membrane and the specificity of a molecularly imprinted polymer for the extraction of polycyclic aromatic hydrocarbons from wastewater sludge followed by quantitation using gas chromatography with time-of-flight mass spectrometry. The approach is described as the Soxhlet extraction membrane-assisted solvent extraction molecularly imprinted polymer technique. This technique was optimised for various parameters such as extraction solvent, reflux time and membrane acceptor phase. The applicability of the developed technique was optimised using a wastewater sludge certified reference material and then tested on real wastewater sludge samples. The method detection limits ranged from 0.14 to 12.86 ng/g with relative standard deviation values for the extraction of the 16 US-EPA priority polycyclic aromatic hydrocarbons from wastewater sludge samples ranging from 0.78 to 18%. The extraction process was therefore reproducible and showed remarkable selectivity. The developed technique is a promising prospect that can be applied in the analysis of organic pollutants from complex solid samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Dummy-surface molecularly imprinted polymers as a sorbent of micro-solid-phase extraction combined with dispersive liquid-liquid microextraction for determination of five 2-phenylpropionic acid NSAIDs in aquatic environmental samples.

    Science.gov (United States)

    Guo, Ping; Yuan, Xucan; Zhang, Jingjing; Wang, Binjie; Sun, Xiaoyang; Chen, Xiaohui; Zhao, Longshan

    2018-01-01

    their environmental fate and risk to ecological health. Graphical abstract Dummy-surface molecularly imprinted polymers as a sorbent of micro-solid-phase extraction combined with dispersive liquid-liquid microextraction for determination of five 2-phenylpropionic acid NSAIDs in aquatic environmental samples.

  6. Selective molecularly imprinted polymer combined with restricted access material for in-tube SPME/UHPLC-MS/MS of parabens in breast milk samples

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Israel D.; Melo, Lidervan P. [Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Jardim, Isabel C.S.F. [Instituto de Química, Universidade Estadual de Campinas, Campinas, SP (Brazil); Monteiro, Juliana C.S.; Nakano, Ana Marcia S. [Escola de Enfermagem de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Queiroz, Maria Eugênia C., E-mail: mariaeqn@ffclrp.usp.br [Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

    2016-08-17

    A new molecularly imprinted polymer modified with restricted access material (a hydrophilic external layer), (MIP-RAM) was synthesized via polymerization in situ in an open fused silica capillary. This stationary phase was used as sorbent for in-tube solid phase microextraction (in-tube SPME) to determine parabens in breast milk samples by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Scanning electron micrographs (SEM) illustrate MIP surface modification after glycerol dimethacrylate (hydrophilic monomer) incorporation. The interaction between parabens and MIP-RAM was investigated by Fourier-transform infrared (FTIR) spectroscopy. The Scatchard plot for MIP-RAM presented two linear parts with different slopes, illustrating binding sites with high- and low-affinity. Endogenous compounds exclusion from the MIP-RAM capillary was demonstrated by in-tube SPME/LC-UV assays carried out with blank milk samples. The in-tube SPME/UHPLC-MS/MS method presented linear range from 10 ng mL{sup −1} (LLOQ) to 400 ng mL{sup −1} with coefficients of determination higher than 0.99, inter-assay precision with coefficient of variation (CV) values ranging from 2 to 15%, and inter-assay accuracy with relative standard deviation (RSD) values ranging from −1% to 19%. Analytical validation parameters attested that in-tube SPME/UHPLC-MS/MS is an appropriate method to determine parabens in human milk samples to assess human exposure to these compounds. Analysis of breast milk samples from lactating women demonstrated that the proposed method is effective. - Highlights: • Molecularly imprinted polymer modified with a hydrophilic external layer (RAM-MIP) was synthesized in a silica capillary. • RAM-MIP capillary, used as sorbent for in-tube SPME, established specific interaction with parabens present in milk samples. • The matrix components that interacted only with the hydrophilic external layer (non-adsorptive network) were excluded.

  7. Conducting Polymer 3D Microelectrodes

    Directory of Open Access Journals (Sweden)

    Jenny Emnéus

    2010-12-01

    Full Text Available Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described electrodes are possibly suitable for future in-vitro neurological measurements.

  8. Diffraction behavior of a birefringence grating and a surface relief grating recorded on an azo polymer film by using writing beams with a (+45 .deg. , -45 .deg. ) polarization combination

    International Nuclear Information System (INIS)

    Hwang, Ui-Jung; Kim, Jung-Sung; Oh, Cha-Hwan; Lee, Geon-Joon; Lee, Young-Pak; Song, Seok-Ho; Kim, Pill-Soo; Han, Yang-Kyoo

    2004-01-01

    By employing an orthogonal linear-polarization combination, (+45 .deg. ,-45 .deg. ), we prepared a surface relief grating (SRG) and a birefringence grating (BG) on an azo polymer film. Atomic force microscopy (AFM) showed that the SRG height gradually increased, and the height was 56.5 nm at an input fluence of 63 J/cm 2 . All the diffraction orders from the gratings were measured simultaneously, and the BG characteristics were analyzed from the s and the p components of the first-order diffraction beam and the measured SRG height. The BG showed an abrupt increase in the beginning of writing, but decreased shortly later, and became smaller than the SRG at a few minutes after writing. The phase shift between the two gratings was determined to be π, which is crucial for determining the SRG formation mechanism.

  9. Polymer liquids fracture like solids

    DEFF Research Database (Denmark)

    Huang, Qian; Hassager, Ole

    2017-01-01

    While fracture in brittle solids has been studied for centuries until today, there are few studies on fracture in polymer liquids. Recent developments in experimental techniques, especially the combination of controlled filament stretching rheometry and high speed imaging, have opened new windows...... into the detailed study of fracture processes for polymer liquids. High speed imaging shows that polymer liquids fracture like solids with initiation and propagation of an edge fracture. However, remarkable features such as highly reproducible critical stress, independent appearance of multiple fractures...

  10. A novel approach for the fabrication of a flexible glucose biosensor: The combination of vertically aligned CNTs and a conjugated polymer.

    Science.gov (United States)

    Gokoglan, Tugba Ceren; Soylemez, Saniye; Kesik, Melis; Dogru, Itir Bakis; Turel, Onur; Yuksel, Recep; Unalan, Husnu Emrah; Toppare, Levent

    2017-04-01

    A novel flexible glucose biosensor using vertically aligned carbon nanotubes (VACNT) and a conjugated polymer (CP) was fabricated. A scaffold based on VACNT grown on aluminum foil (VACNT-Al foil) with poly (9,9-di-(2-ethylhexyl)-fluorenyl-2,7-diyl)-end capped with 2,5-diphenyl-1,2,4-oxadiazole (PFLO) was used as the immobilization matrix for the glucose biosensor. Glucose oxidase (GOx) was immobilized on a modified indium tin oxide (ITO) coated polyethylene terephthalate (PET) electrode surface. The biosensor response at a potential of -0.7V versus Ag wire was followed by the decrease in oxygen level as a result of enzymatic reaction. The biosensor exhibited a linear range between 0.02mM and 0.5mM glucose and kinetic parameters (K M app , I max , limit of detection (LOD) and sensitivity) were estimated as 0.193mM, 8.170μA, 7.035×10 -3 mM and 65.816μA/mMcm 2 , respectively. Scanning electron microscopy (SEM) was used for surface characterization. The constructed biosensor was applied to determine the glucose content in several beverages. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Topographical and Chemical Imaging of a Phase Separated Polymer Using a Combined Atomic Force Microscopy/Infrared Spectroscopy/Mass Spectrometry Platform.

    Science.gov (United States)

    Tai, Tamin; Karácsony, Orsolya; Bocharova, Vera; Van Berkel, Gary J; Kertesz, Vilmos

    2016-03-01

    In this paper, the use of a hybrid atomic force microscopy/infrared spectroscopy/mass spectrometry imaging platform was demonstrated for the acquisition and correlation of nanoscale sample surface topography and chemical images based on infrared spectroscopy and mass spectrometry. The infrared chemical imaging component of the system utilized photothermal expansion of the sample at the tip of the atomic force microscopy probe recorded at infrared wave numbers specific to the different surface constituents. The mass spectrometry-based chemical imaging component of the system utilized nanothermal analysis probes for thermolytic surface sampling followed by atmospheric pressure chemical ionization of the gas phase species produced with subsequent mass analysis. The basic instrumental setup, operation, and image correlation procedures are discussed, and the multimodal imaging capability and utility are demonstrated using a phase separated poly(2-vinylpyridine)/poly(methyl methacrylate) polymer thin film. The topography and both the infrared and mass spectral chemical images showed that the valley regions of the thin film surface were comprised primarily of poly(2-vinylpyridine) and hill or plateau regions were primarily poly(methyl methacrylate). The spatial resolution of the mass spectral chemical images was estimated to be 1.6 μm based on the ability to distinguish surface features in those images that were also observed in the topography and infrared images of the same surface.

  12. Polymer electronics

    CERN Document Server

    Geoghegan, Mark

    2013-01-01

    Polymer electronics is the science behind many important new developments in technology, such as the flexible electronic display (e-ink) and many new developments in transistor technology. Solar cells, light-emitting diodes, and transistors are all areas where plastic electronics is likely to, or is already having, a serious impact on our daily lives. With polymer transistors and light-emitting diodes now being commercialised, there is a clear need for a pedagogic text thatdiscusses the subject in a clear and concise fashion suitable for senior undergraduate and graduate students. The content

  13. Degradation of Fluorotelomer-Based Polymers Contributes to the Global Occurrence of Fluorotelomer Alcohol and Perfluoroalkyl Carboxylates: A Combined Dynamic Substance Flow and Environmental Fate Modeling Analysis.

    Science.gov (United States)

    Li, Li; Liu, Jianguo; Hu, Jianxin; Wania, Frank

    2017-04-18

    Using coupled dynamic substance flow and environmental fate models, CiP-CAFE and BETR-Global, we investigated whether the degradation of side-chain fluorotelomer-based polymers (FTPs), mostly in waste stocks (i.e., landfills and dumps), serves as a long-term source of fluorotelomer alcohols (FTOHs) and perfluoroalkyl carboxylates (PFCAs) to the global environment. The modeling results indicate that, in the wake of the worldwide transition from long-chain to short-chain products, in-use stocks of C8 FTPs will peak and decline afterward, while the in-use stocks of C6 FTPs, and the waste stocks of both FTPs will generally grow. FTP degradation in waste stocks is making an increasing contribution to FTOH generation, the bulk of which readily migrates from waste stocks and degrades into PFCAs in the environment; the remaining part of the generated FTOHs degrade in waste stocks, which makes those stocks reservoirs that slowly release PFCAs into the environment over the long run because of the low leaching rate and extreme persistence of PFCAs. Short-chain FTPs have higher relative release rates of PFCAs from waste stocks than long-chain ones. Estimates of in-use and waste stocks of FTPs were more sensitive to the selected lifespan of finished products, while those of the emissions of FTOHs and PFCAs were more sensitive to the degradation half-life of FTPs in waste stocks. Our preliminary calculations highlight the need for environmentally sound management of obsolete FTP-containing products into the foreseeable future.

  14. Ultrasound assisted combined molecularly imprinted polymer for selective extraction of nicotinamide in human urine and milk samples: Spectrophotometric determination and optimization study.

    Science.gov (United States)

    Asfaram, Arash; Ghaedi, Mehrorang; Dashtian, Kheibar

    2017-01-01

    Ultrasound-assisted dispersive solid phase microextraction followed by UV-vis spectrophotometer (UA-DSPME-UV-vis) was designed for extraction and preconcentration of nicotinamide (vitamin B 3 ) by HKUST-1 metal organic framework (MOF) based molecularly imprinted polymer (MIP). This new material was characterized by FTIR and FE-SEM techniques. The preliminary Plackett-Burman design was used for screening and subsequently the central composite design justifies significant terms and possible construction of mathematical equation which give the individual and cooperative contribution of variables like HKUST-1-MOF-NA-MIP mass, sonication time, temperature, eluent volume, pH and vortex time. Accordingly the optimum condition was set as: 2.0mg HKUST-1-MOF-NA-MIP, 200μL eluent and 5.0min sonication time in center points other variables were determined as the best conditions to reach the maximum recovery of the analyte. The UA-DSPME-UV-vis method performances like excellent linearity (LR), limits of detection (LOD), limits of quantification of 10-5000μgL -1 with R 2 of 0.99, LOD (1.96ngmL -1 ), LOQ (6.53μgL -1 ), respectively show successful and accurate applicability of the present method for monitoring analytes with within- and between-day precision of 0.96-3.38%. The average absolute recoveries of the nicotinamide extracted from the urine, milk and water samples were 95.85-101.27%. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Selective molecularly imprinted polymer combined with restricted access material for in-tube SPME/UHPLC-MS/MS of parabens in breast milk samples.

    Science.gov (United States)

    Souza, Israel D; Melo, Lidervan P; Jardim, Isabel C S F; Monteiro, Juliana C S; Nakano, Ana Marcia S; Queiroz, Maria Eugênia C

    2016-08-17

    A new molecularly imprinted polymer modified with restricted access material (a hydrophilic external layer), (MIP-RAM) was synthesized via polymerization in situ in an open fused silica capillary. This stationary phase was used as sorbent for in-tube solid phase microextraction (in-tube SPME) to determine parabens in breast milk samples by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Scanning electron micrographs (SEM) illustrate MIP surface modification after glycerol dimethacrylate (hydrophilic monomer) incorporation. The interaction between parabens and MIP-RAM was investigated by Fourier-transform infrared (FTIR) spectroscopy. The Scatchard plot for MIP-RAM presented two linear parts with different slopes, illustrating binding sites with high- and low-affinity. Endogenous compounds exclusion from the MIP-RAM capillary was demonstrated by in-tube SPME/LC-UV assays carried out with blank milk samples. The in-tube SPME/UHPLC-MS/MS method presented linear range from 10 ng mL(-1) (LLOQ) to 400 ng mL(-1) with coefficients of determination higher than 0.99, inter-assay precision with coefficient of variation (CV) values ranging from 2 to 15%, and inter-assay accuracy with relative standard deviation (RSD) values ranging from -1% to 19%. Analytical validation parameters attested that in-tube SPME/UHPLC-MS/MS is an appropriate method to determine parabens in human milk samples to assess human exposure to these compounds. Analysis of breast milk samples from lactating women demonstrated that the proposed method is effective. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Comparison of the operation of polymer/fullerene, polymer/polymer, and polymer/nanocrystal solar cells: a transient photocurrent and photovoltage study

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhe; Gao, Feng; Greenham, Neil C.; McNeill, Christopher R. [Cavendish Laboratory, University of Cambridge, J J Thomson Ave, Cambridge, CB3 0HE (United Kingdom)

    2011-04-22

    We utilize transient techniques to directly compare the operation of polymer/fullerene, polymer/nanocrystal, and polymer/polymer bulk heterojunction solar cells. For all devices, poly(3-hexylthiophene) (P3HT) is used as the electron donating polymer, in combination with either the fullerene derivative phenyl-C{sub 61}-butyric acid methyl ester (PCBM) in polymer/fullerene cells, CdSe nanoparticles in polymer/nanocrystal cells, or the polyfluorene copolymer poly((9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(3-hexylthien-5-yl)-2,1,3-benzothiadiazole]-2,2-diyl) (F8TBT) in polymer/polymer cells. Transient photocurrent and photovoltage measurements are used to probe the dynamics of charge-separated carriers, with vastly different dynamic behavior observed for polymer/fullerene, polymer/polymer, and polymer/nanocrystal devices on the microsecond to millisecond timescale. Furthermore, by employing transient photocurrent analysis with different applied voltages we are also able to probe the dynamics behavior of these cells from short circuit to open circuit. P3HT/F8TBT and P3HT/CdSe devices are characterized by poor charge extraction of the long-lived carriers attributed to charge trapping. P3HT/PCBM devices, in contrast, show relatively trap-free operation with the variation in the photocurrent decay kinetics with applied bias at low intensity, consistent with the drift of free charges under a uniform electric field. Under solar conditions at the maximum power point, we see direct evidence of bimolecular recombination in the P3HT/PCBM device competing with charge extraction. Transient photovoltage measurements reveal that, at open circuit, photogenerated charges have similar lifetimes in all device types, and hence, the extraction of these long-lived charges is a limiting process in polymer/nanocrystal and polymer/polymer devices. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Optical sensors from electrohydrodynamic jetted polymer fiber resonators

    DEFF Research Database (Denmark)

    Laye, Fabrice; Kraemmer, Sarah; Castillo, Alejandro

    2016-01-01

    Electrohydrodynamic jetting is used to manufacture dye-doped polymer fiber resonators. We present comb-like laser emission from different polymer/dye combinations and report the use of these structures as sensitive detection of ethanol and methanol.......Electrohydrodynamic jetting is used to manufacture dye-doped polymer fiber resonators. We present comb-like laser emission from different polymer/dye combinations and report the use of these structures as sensitive detection of ethanol and methanol....

  18. Conducting Polymers

    Indian Academy of Sciences (India)

    backbone (by the process of doping) and make them electrically. Conducting Polymers. From a Laboratory Curiosity to the Market Place. S Ramakrishnan ..... switching occurs between transparent yellow and green in less than. 100ms. Thus, while these materials are yet to achieve the set target. (in terms of their life cycle) ...

  19. Conducting Polymers

    Indian Academy of Sciences (India)

    ized the plastics industry by providing a route to polypropylene. (Zeigler and Natta jointly won the. Nobel Prize in Chemistry in 1963 for their discovery.) ... transport of charge in these systems can be understood in a simple fashion, by causing the imine and amine nitrogens to exchange places along the polymer backbone (in ...

  20. Conducting Polymers

    Indian Academy of Sciences (India)

    the plastics industry by providing a route to polypropylene. (Zeigler and Natta jointly won the Nobel Prize in chemistry in 1963 for their discovery.) ... these systems can be understood in a simple fashion, by causing the imine and amine nitrogens to exchange places along the polymer backbone (in protonated emeraldinel.

  1. Conducting Polymers

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 12. Conducting Polymers - From a Laboratory Curiosity to the Market Place. S Ramakrishnan. Volume 16 Issue 12 December 2011 pp 1254-1265. Fulltext. Click here to view fulltext PDF. Permanent link:

  2. Polymer solutions

    Science.gov (United States)

    Krawczyk, Gerhard Erich [Bremen, DE; Miller, Kevin Michael [West Dundee, IL

    2011-07-26

    There is provided a method of making a polymer solution comprising polymerizing one or more monomer in a solvent, wherein said monomer comprises one or more ethylenically unsaturated monomer that is a multi-functional Michael donor, and wherein said solvent comprises 40% or more by weight, based on the weight of said solvent, one or more multi-functional Michael donor.

  3. Polymer physics

    CERN Document Server

    Gedde, Ulf W

    1999-01-01

    This book is the result of my teaching efforts during the last ten years at the Royal Institute of Technology. The purpose is to present the subject of polymer physics for undergraduate and graduate students, to focus the fundamental aspects of the subject and to show the link between experiments and theory. The intention is not to present a compilation of the currently available literature on the subject. Very few reference citations have thus been made. Each chapter has essentially the same structure: starling with an introduction, continuing with the actual subject, summarizing the chapter in 30D-500 words, and finally presenting problems and a list of relevant references for the reader. The solutions to the problems presented in Chapters 1-12 are given in Chapter 13. The theme of the book is essentially polymer science, with the exclusion of that part dealing directly with chemical reactions. The fundamentals in polymer science, including some basic polymer chemistry, are presented as an introduction in t...

  4. Supramolecular polymers

    National Research Council Canada - National Science Library

    Ciferri, A

    2000-01-01

    ... to the new class of self-assembled polymers that undergo reversible growth by the formation of noncovalent bonds. This class (Part II) is wider than expected: not only mainchain assemblies of hydrogen-bonded repeating units, but also planar organization of S-layer proteins, micellar and related three-dimensional structures of blo...

  5. Solution Behavior of Responsive Cationic Polymers

    OpenAIRE

    Karjalainen, Erno

    2015-01-01

    This thesis combines anion responsive polymeric ionic liquids (PILs) with thermoresponsive polymers. The polymers have been synthesized with controlled radical polymerization methods. A water-insoluble PIL was used as a macro-chain transfer agent in synthesis of block copolymers with poly(N-isopropyl acrylamide) (PNIPAm). PNIPAm chains of various lengths were grown to the same PIL-block. These polymers show a lower cirical solution temperature (LCST) type behavior, typical to PNIPAm. The...

  6. Performance limitations of polymer electrolytes based on ethylene oxide polymers

    International Nuclear Information System (INIS)

    Buriez, Olivier; Han, Yong Bong; Hou, Jun; Kerr, John B.; Qiao, Jun; Sloop, Steven E.; Tian, Minmin; Wang, Shanger

    1999-01-01

    Studies of polymer electrolyte solutions for lithium-polymer batteries are described. Two different salts, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium trifluoromethanesulfonate (LiTf), were dissolved in a variety of polymers. The structures were all based upon the ethylene oxide unit for lithium ion solvation and both linear and comb-branch polymer architectures have been examined. Conductivity, salt diffusion coefficient and transference number measurements demonstrate the superior transport properties of the LiTFSI salt over LiTf. Data obtained on all of these polymers combined with LiTFSI salts suggest that there is a limit to the conductivity achievable at room temperature, at least for hosts containing ethylene oxide units. The apparent conductivity limit is 5 x 10-5 S/cm at 25 C. Providing that the polymer chain segment containing the ethylene oxide units is at least 5-6 units long there appears to be little influence of the polymer framework to which the solvating groups are attached. To provide adequate separator function, the mechanical properties may be disconnected from the transport properties by selection of an appropriate architecture combined with an adequately long ethylene oxide chain. For both bulk and interfacial transport of the lithium ions, conductivity data alone is insufficient to understand the processes that occur. Lithium ion transference numbers and salt diffusion coefficients also play a major role in the observed behavior and the transport properties of these polymer electrolyte solutions appear to be quite inadequate for ambient temperature performance. At present, this restricts the use of such systems to high temperature applications. Several suggestions are given to overcome these obstacles

  7. Interpenetrating networks of two conducting polymers

    DEFF Research Database (Denmark)

    Winther-Jensen, Bjørn; West, Keld

    2005-01-01

    Interpenetrating networks (IPNs) of two conjugated polymers are prepared by a combination of a chemical oxidation step and a vapour phase polymerisation step on non-conducting surfaces. In this work ferric tosylate was used as the oxidant as it gives very smooth and homogeneous coatings, and beca......Interpenetrating networks (IPNs) of two conjugated polymers are prepared by a combination of a chemical oxidation step and a vapour phase polymerisation step on non-conducting surfaces. In this work ferric tosylate was used as the oxidant as it gives very smooth and homogeneous coatings......, and because its reaction products can be removed efficiently after the formation of the composite. Several combinations of polymers are demonstrated, and the versatility of the proposed method allows extensions to a wide range of conjugated polymers. The IPNs show optical and electrochemical characteristics......, which are sums of the characteristics from the participating conducting polymers....

  8. Antiviral Polymer Therapeutics

    DEFF Research Database (Denmark)

    Smith, Anton Allen Abbotsford

    2014-01-01

    The field of drug delivery is in essence an exercise in engineered pharmacokinetics. Methods of doing so have been developed through the introduction of a vehicle carrying the drug, either by encapsulation or covalent attachment. The emergence of polymer therapeutics in anticancer therapy has...... garnered a great deal of interest due to the substantial room for improvement inherent to conventional chemotherapeutic agents. Chemotherapeutic agents and antiviral agents have a lot of features in common due to both of them typically targeting endogenous targets, unlike antibacterial compounds, though...... the examples of polymer therapeutics being applied as an antiviral treatment are few and far in-between. This work aims to explore antiviral therapeutics, specifically in context of hepatitis virus C (HCV) and HIV. The current treatment of hepatitis C consists of a combination of drugs, of which ribavirin...

  9. How do polymers degrade?

    Science.gov (United States)

    Lyu, Suping

    2011-03-01

    Materials derived from agricultural products such as cellulose, starch, polylactide, etc. are more sustainable and environmentally benign than those derived from petroleum. However, applications of these polymers are limited by their processing properties, chemical and thermal stabilities. For example, polyethylene terephthalate fabrics last for many years under normal use conditions, but polylactide fabrics cannot due to chemical degradation. There are two primary mechanisms through which these polymers degrade: via hydrolysis and via oxidation. Both of these two mechanisms are related to combined factors such as monomer chemistry, chain configuration, chain mobility, crystallinity, and permeation to water and oxygen, and product geometry. In this talk, we will discuss how these materials degrade and how the degradation depends on these factors under application conditions. Both experimental studies and mathematical modeling will be presented.

  10. Polymer blends

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Scott D.; Naik, Sanjeev

    2017-08-22

    The present invention provides, among other things, extruded blends of aliphatic polycarbonates and polyolefins. In one aspect, provided blends comprise aliphatic polycarbonates such as poly(propylene carbonate) and a lesser amount of a crystalline or semicrystalline polymer. In certain embodiments, provided blends are characterized in that they exhibit unexpected improvements in their elongation properties. In another aspect, the invention provides methods of making such materials and applications of the materials in applications such as the manufacture of consumer packaging materials.

  11. Systems for production of polymer encapsuated solids

    Energy Technology Data Exchange (ETDEWEB)

    Bourcier, William L.; Aines, Roger D.; Baker, Sarah E.; Duoss, Eric B.; Maiti, Amitesh; Roberts, Jeffery J.; Spadaccini, Christopher M.; Stolaroff, Joshuah K.; Vericella, John J.; Lewis, Jennifer A.; Hardin, IV, James O.; Floyd, III, William C.

    2017-11-21

    Encapsulated solids are made by first encapsulating precursor materials in a polymer shell. The precursors are some combination of solids, liquids, gases, and/or gels. The precursors are then transformed into solids by emplacement of the capsule in an environment where gas or fluid transport into or out of the polymer shell causes transformation into solids.

  12. Fabrication of silicon molds for polymer optics

    DEFF Research Database (Denmark)

    Nilsson, Daniel; Jensen, Søren; Menon, Aric Kumaran

    2003-01-01

    A silicon mold used for structuring polymer microcavities for optical applications is fabricated, using a combination of DRIE (deep reactive ion etching) and anisotropic chemical wet etching with KOH + IPA. For polymer optical microcavities, low surface roughness and vertical sidewalls are often ...... and KOH + IPA etch have been optimized. To reduce stiction between the silicon mold and the polymers used for molding, the mold is coated with a teflon-like material using the DRIE system. Released polymer microstructures characterized with AFM and SEM are also presented....

  13. Compatibilized Immiscible Polymer Blends for Gas Separations

    Science.gov (United States)

    Panapitiya, Nimanka; Wijenayake, Sumudu; Nguyen, Do; Karunaweera, Chamaal; Huang, Yu; Balkus, Kenneth; Musselman, Inga; Ferraris, John

    2016-01-01

    Membrane-based gas separation has attracted a great deal of attention recently due to the requirement for high purity gasses in industrial applications like fuel cells, and because of environment concerns, such as global warming. The current methods of cryogenic distillation and pressure swing adsorption are energy intensive and costly. Therefore, polymer membranes have emerged as a less energy intensive and cost effective candidate to separate gas mixtures. However, the use of polymeric membranes has a drawback known as the permeability-selectivity tradeoff. Many approaches have been used to overcome this limitation including the use of polymer blends. Polymer blending technology synergistically combines the favorable properties of different polymers like high gas permeability and high selectivity, which are difficult to attain with a single polymer. During polymer mixing, polymers tend to uncontrollably phase separate due to unfavorable thermodynamics, which limits the number of completely miscible polymer combinations for gas separations. Therefore, compatibilizers are used to control the phase separation and to obtain stable membrane morphologies, while improving the mechanical properties. In this review, we focus on immiscible polymer blends and the use of compatibilizers for gas separation applications. PMID:28773766

  14. Fe2O3-loaded activated carbon fiber/polymer materials and their photocatalytic activity for methylene blue mineralization by combined heterogeneous-homogeneous photocatalytic processes

    Science.gov (United States)

    Kadirova, Zukhra C.; Hojamberdiev, Mirabbos; Katsumata, Ken-Ichi; Isobe, Toshihiro; Matsushita, Nobuhiro; Nakajima, Akira; Okada, Kiyoshi

    2017-04-01

    Fe2O3-supported activated carbon felts (Fe-ACFTs) were prepared by impregnating the felts consisted of activated carbon fibers (ACFs) with either polyester fibers (PS-A20) or polyethylene pulp (PE-W15) in Fe(III) nitrate solution and calcination at 250 °C for 1 h. The prepared Fe-ACFTs with 31-35 wt% Fe were characterized by N2-adsorption, scanning electron microscopy, and X-ray diffraction. The Fe-ACFT(PS-A20) samples with 5-31 wt% Fe were microporous with specific surface areas (SBET) ranging from 750 to 150 m2/g, whereas the Fe-ACFT(PE-W15) samples with 2-35 wt% Fe were mesoporous with SBET ranging from 830 to 320 m2/g. The deposition of iron oxide resulted in a decrease in the SBET and methylene blue (MB) adsorption capacity while increasing the photodegradation of MB. The optimum MB degradation conditions included 0.98 mM oxalic acid, pH = 3, 0.02-0.05 mM MB, and 100 mg/L photocatalyst. The negative impact of MB desorption during the photodegradation reaction was more pronounced for mesoporous PE-W15 samples and can be neglected by adding oxalic acid in cyclic experiments. Almost complete and simultaneous mineralization of oxalate and MB was achieved by the combined heterogeneous-homogeneous photocatalytic processes. The leached Fe ions in aqueous solution [Fe3+]f were measured after 60 min for every cycle and found to be about 2 ppm in all four successive cycles. The developed photocatalytic materials have shown good performance even at low content of iron oxide (2-5 wt% Fe-ACFT). Moreover, it is easy to re-impregnate the ACF when the content of iron oxide is reduced during the cyclic process. Thus, low leaching of Fe ions and possibility of cyclic usage are the advantages of the photocatalytic materials developed in this study.

  15. Characterizing the Polymer:Fullerene Intermolecular Interactions

    KAUST Repository

    Sweetnam, Sean

    2016-02-02

    Polymer:fullerene solar cells depend heavily on the electronic coupling of the polymer and fullerene molecular species from which they are composed. The intermolecular interaction between the polymer and fullerene tends to be strong in efficient photovoltaic systems, as evidenced by efficient charge transfer processes and by large changes in the energetics of the polymer and fullerene when they are molecularly mixed. Despite the clear presence of these strong intermolecular interactions between the polymer and fullerene, there is not a consensus on the nature of these interactions. In this work, we use a combination of Raman spectroscopy, charge transfer state absorption, and density functional theory calculations to show that the intermolecular interactions do not appear to be caused by ground state charge transfer between the polymer and fullerene. We conclude that these intermolecular interactions are primarily van der Waals in nature. © 2016 American Chemical Society.

  16. Functional Films from Silica/Polymer Nanoparticles

    Directory of Open Access Journals (Sweden)

    Tânia Ribeiro

    2014-05-01

    Full Text Available High performance functional coatings, based on hybrid organic/inorganic materials, are being developed to combine the polymer flexibility and ease of processing with the mechanical properties and versatility of inorganic materials. By incorporating silica nanoparticles (SiNPs in the polymeric matrices, it is possible to obtain hybrid polymer films with increased tensile strength and impact resistance, without decreasing the flexural properties of the polymer matrix. The SiNPs can further be used as carriers to impart other functionalities (optical, etc. to the hybrid films. By using polymer-coated SiNPs, it is possible to reduce particle aggregation in the films and, thus, achieve more homogeneous distributions of the inorganic components and, therefore, better properties. On the other hand, by coating polymer particles with silica, one can create hierarchically structured materials, for example to obtain superhydrophobic coatings. In this review, we will cover the latest developments in films prepared from hybrid polymer/silica functional systems.

  17. All-Polymer Lasers

    Science.gov (United States)

    Wu, Yeheng; Lott, Joseph; Kazmierczak, Tomasz; Song, Hyunmin; Baer, Eric; Singer, Kenneth; Weder, Christoph

    2008-03-01

    We have fabricated all-polymer lasers both as distributed feedback lasers (DFB) and distributed Bragg reflector (DBR) lasers. For the DBR lasers, a layer of polymer doped with the laser dye is laminated between two multilayer polymer mirrors. The mirrors were made using the co-extrusion process combining PMMA alternated with polystyrene with 128 layers for each mirror. Two dyes were employed, Rhodamine 6G (R6G), and 1,4-bis-(α-cyano-4-methoxystyryl)-2,5-dimethoxybenzene (C1RG). They were pumped with a nanosecond laser and emitted at about 570 and 510 nm respectively. For DFB lasers, the low refractive index layers were doped with C1RG or R6G. PMMA and PMMA-PVDF were the hosts for the C1RG and R6G respectively. A total of eight co-extruded 32-layer films were stacked together to make a DFB laser. For the DBR lasers, we were able to observe thresholds as low as 100nJ. The highest conversion efficiency obtained about 14% in the forward direction. We also observed trends of lasing threshold, even spaced lasing modes and penetration of the film. Matrix method simulations taking into account layer thickness variations were consistent with experimental results. For the DFB lasers, the lowest lasing threshold observed was 52 μW.

  18. BioArtificial polymers

    Science.gov (United States)

    Szałata, Kamila; Gumi, Tania

    2017-07-01

    Nowadays, the polymer science has impact in practically all life areas. Countless benefits coming from the usage of materials with high mechanical and chemical resistance, variety of functionalities and potentiality of modification drive to the development of new application fields. Novel approaches of combining these synthetic substances with biomolecules lead to obtain multifunctional hybrid conjugates which merge the bioactivity of natural component with outstanding properties of artificial polymer. Over the decades, an immense progress in bioartificial composites domain allowed to reach a high level of knowledge in terms of natural-like systems engineering, leading to diverse strategies of biomolecule immobilization. Together with different available options, including covalent and noncovalent attachment, come various challenges, related mainly with maintaining the biological activity of fixed molecules. Even though the amount of applications that achieve commercial status is still not substantial, and is expanding continuously in the disciplines like "smart materials," biosensors, delivery systems, nanoreactors and many others. A huge number of remarkable developments reported in the literature present a potential of bioartificial conjugates as a fabrics with highly controllable structure and multiple functionalities, serving as a powerful nanotechnological tool. This novel approach brings closer biologists, chemists and engineers, who sharing their effort and complementing the knowledge can revolutionize the field of bioartificial polymer science.

  19. Classical ultraviolet photoelectron spectroscopy of polymers

    International Nuclear Information System (INIS)

    Salaneck, W.R.

    2009-01-01

    Although X-ray photoelectron spectroscopy of polymers was well established by Clark and coworkers in the 1970s, ultraviolet photoelectron spectroscopy of polymer films, was developed later. Previous to the 1970s, the first attempts to use ultraviolet light on polymer films took the form of appearance potential (valence band edge) measurements. Only some years later could the full valence band region of thin polymer films, including insulating polymers, semiconducting polymers and electrically conducting polymers. The development of what might be termed 'classical ultraviolet photoelectron spectroscopy' of polymer films may be loosely based upon a variety of issues, including adapting thin polymer film technology to ultra high vacuum studies, the widespread use of helium resonance lamps for studies of solid surfaces, the combined advent of practical and sufficient theoretical-computational methods. The advent of, and the use of, easily available synchrotron radiation for multi-photon spectroscopies, nominally in the area of the near UV, is not included in the term 'classical'. At the same time, electrically conducting polymers were discovered, leading to applications of the corresponding semiconducting polymers, which added technologically driven emphasis to this development of ultraviolet photoelectron spectroscopy for polymer materials. This paper traces a limited number of highlights in the evolution of ultraviolet photoelectron spectroscopy of polymers, from the 1970s through to 2008. Also, since this issue is dedicated to Prof. Kazuhiko Seki, who has been a friend and competitor for over two decades, the author relies on some of Prof. Seki's earlier research, unpublished, on who-did-what-first. Prof. Seki's own contributions to the field, however, are discussed in other articles in this issue.

  20. FTIR Drug-Polymer Interactions Studies of Perindopril Erbumine

    International Nuclear Information System (INIS)

    Modni, A.; Ahmad, S.; Din, I.; Hussain, Z.

    2014-01-01

    The present study was carried out to prepare different combinations of Perindopril Erbumine with different polymers like Hydroxy propyl methyl cellulose, Hydroxy propyl methyl cellulose K4M, Hydroxy propyl methyl cellulose K15M, Xanthan gum and Ethyl cellulose, thereby to determine any possible interactions between Perindopril erbumine and polymers. The analytical technique Fourier Transform Infrared (FTIR) spectroscopy was used to take spectra of individual drug, polymers and combination of drug with polymers. The results were analyzed to find out any interactions of Perindopril erbumine and polymers. From this study it was concluded that there were no any significant changes in characteristic peaks of drug after combinations with polymers which indicated no interaction between Perindopril erbumine and polymers. (author)

  1. A simple constitutive model for a polymer flow near a polymer-grafted wall

    NARCIS (Netherlands)

    Stepanyan, R.; Slot, J.J.M.; Molenaar, J.; Tchesnokov, M.A.

    2005-01-01

    A simple constitutive model is proposed to describe a polymer flow near a polymer-grafted wall. The model is based on a generalization of the Rolie-Poly equation [A. E. Likhtman and R. S. Graham, J. Non-Newton. Fluid Mech. 114, 1¿12 (2003)] to a "bulk+wall" system combined with a microscopic picture

  2. From commodity polymers to functional polymers.

    Science.gov (United States)

    Xiang, Tao; Wang, Ling-Ren; Ma, Lang; Han, Zhi-Yuan; Wang, Rui; Cheng, Chong; Xia, Yi; Qin, Hui; Zhao, Chang-Sheng

    2014-04-08

    Functional polymers bear specified chemical groups, and have specified physical, chemical, biological, pharmacological, or other uses. To adjust the properties while keeping material usage low, a method for direct synthesis of functional polymers is indispensable. Here we show that various functional polymers can be synthesized by in situ cross-linked polymerization/copolymerization. We demonstrate that the polymers synthesized by the facile method using different functional monomers own outstanding pH-sensitivity and pH-reversibility, antifouling property, antibacterial, and anticoagulant property. Our study opens a route for the functionalization of commodity polymers, which lead to important advances in polymeric materials applications.

  3. Photochemical stability of π-conjugated polymers for polymer solar cells: a rule of thumb

    DEFF Research Database (Denmark)

    Manceau, Matthieu; Bundgaard, Eva; Carlé, Jon Eggert

    2011-01-01

    A comparative photochemical stability study of a wide range of π-conjugated polymers relevant to polymer solar cells is presented. The behavior of each material has been investigated under simulated sunlight (1 sun, 1000 W m−2, AM 1.5G) and ambient atmosphere. Degradation was monitored during...... ageing combining UV-visible and infrared spectroscopies. From the comparison of the collected data, the influence of the polymer chemical structure on its stability has been discussed. General rules relative to the polymer structure–stability relationship are proposed....

  4. [New polymer-drug systems based on natural and synthetic polymers].

    Science.gov (United States)

    Racoviţă, Stefania; Vasiliu, Silvia; Foia, Liliana

    2010-01-01

    The great versatility of polymers makes them very useful in the biomedical and pharmaceutical fields. The combination of natural and synthetic polymers leads to new materials with tailored functional properties. The aim of this work consists in the preparation of new drug delivery system based on chitosan (natural polymer) and polybetaines (synthetic polymers), by a simple process, well known in the literature as complex coacervation methods. Also, the adsorption and release studies of two antibiotics as well as the preservation of their bactericidal capacities were performed.

  5. Shape memory polymers

    Science.gov (United States)

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  6. Polymers at Surfaces and Interfaces

    Science.gov (United States)

    Tsige, Mesfin

    2015-03-01

    Interfaces between solids, liquids, and gases play an important role in a wide range of practical applications and have been a subject of scientific interest since Poisson showed in 1831 that the order parameter of liquids near interfaces must deviate considerably from its bulk value. In particular, polymers at surfaces and interfaces have been a subject of extensive theoretical, experimental and computational studies for a long time due to their use in many diverse applications ranging from antifouling coatings to flexible electronic devices. Understanding the structure and thermodynamic properties of polymers at surfaces and interfaces is thus an area of fundamental and current technological interest. Although encouraging experimental progress has been made over the years in understanding the molecular structure of polymers in contact with various environments, selectively probing their structure and dynamics at surfaces and interfaces has been extremely difficult. Computer simulations, especially molecular dynamics (MD) simulations, have proven over the years to be an invaluable tool in providing molecular details at interfaces that are usually lacking in the experimental data. In this talk, I'll give an overview of some previous simulation efforts to understand the structure and dynamics of polymers at surfaces and buried interfaces. I will conclude by presenting our current and ongoing work on combining ab initio calculations and MD simulations with Sum Frequency Generation (SFG) Spectroscopy to study polymer surfaces. This approach demonstrates the future role of MD in surface science. Work supported by NSF (DMR0847580 and DMR1410290) and Petroleum Research Fund of the American Chemical Society.

  7. Polymer nanocomposites: polymer and particle dynamics

    KAUST Repository

    Kim, Daniel

    2012-01-01

    Polymer nanocomposites containing nanoparticles smaller than the random coil size of their host polymer chains are known to exhibit unique properties, such as lower viscosity and glass transition temperature relative to the neat polymer melt. It has been hypothesized that these unusual properties result from fast diffusion of the nanostructures in the host polymer, which facilitates polymer chain relaxation by constraint release and other processes. In this study, the effects of addition of sterically stabilized inorganic nanoparticles to entangled cis-1,4-polyisoprene and polydimethylsiloxane on the overall rheology of nanocomposites are discussed. In addition, insights about the relaxation of the host polymer chains and transport properties of nanoparticles in entangled polymer nanocomposites are presented. The nanoparticles are found to act as effective plasticizers for their entangled linear hosts, and below a critical, chemistry and molecular-weight dependent particle volume fraction, lead to reduced viscosity, glass transition temperature, number of entanglements, and polymer relaxation time. We also find that the particle motions in the polymer host are hyperdiffusive and at the nanoparticle length scale, the polymer host acts like a simple, ideal fluid and the composites\\' viscosity rises with increasing particle concentration. © 2012 The Royal Society of Chemistry.

  8. Ionic Liquids in Polymer Design: From Energy to Health

    Science.gov (United States)

    2016-10-19

    is to identify and highlight emerging materials that combine ionic liquids and polymer chemistry and the unique properties that arise from this...combination. This symposium covers all aspects of ionic liquids in polymers from synthesis, properties , and applications. The research should be...ionic liquids 2. Synthesis and Processing 3. Structure- Property Relationships 4. New materials and emerging Applications 5. Energy and Environmental

  9. Biochemical synthesis of water soluble conducting polymers

    International Nuclear Information System (INIS)

    Bruno, Ferdinando F.; Bernabei, Manuele

    2016-01-01

    An efficient biomimetic route for the synthesis of conducting polymers/copolymers complexed with lignin sulfonate and sodium (polystyrenesulfonate) (SPS) will be presented. This polyelectrolyte assisted PEG-hematin or horseradish peroxidase catalyzed polymerization of pyrrole (PYR), 3,4 ethyldioxithiophene (EDOT) and aniline has provided a route to synthesize water-soluble conducting polymers/copolymers under acidic conditions. The UV-vis, FTIR, conductivity and cyclic voltammetry studies for the polymers/copolymer complex indicated the presence of a thermally stable and electroactive polymers. Moreover, the use of water-soluble templates, used as well as dopants, provided a unique combination of properties such as high electronic conductivity, and processability. These polymers/copolymers are nowadays tested/evaluated for antirust features on airplanes and helicopters. However, other electronic applications, such as photovoltaics, for transparent conductive polyaniline, actuators, for polypyrrole, and antistatic films, for polyEDOT, will be proposed.

  10. Biochemical synthesis of water soluble conducting polymers

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, Ferdinando F., E-mail: Ferdinando-Bruno@uml.edu [US Army Natick Soldier Research, Development and Engineering Center, Natick, MA 01760 (United States); Bernabei, Manuele [ITAF, Test Flight Centre, Chemistry Dept. Pratica di Mare AFB, 00071 Pomezia (Rome), Italy (UE) (Italy)

    2016-05-18

    An efficient biomimetic route for the synthesis of conducting polymers/copolymers complexed with lignin sulfonate and sodium (polystyrenesulfonate) (SPS) will be presented. This polyelectrolyte assisted PEG-hematin or horseradish peroxidase catalyzed polymerization of pyrrole (PYR), 3,4 ethyldioxithiophene (EDOT) and aniline has provided a route to synthesize water-soluble conducting polymers/copolymers under acidic conditions. The UV-vis, FTIR, conductivity and cyclic voltammetry studies for the polymers/copolymer complex indicated the presence of a thermally stable and electroactive polymers. Moreover, the use of water-soluble templates, used as well as dopants, provided a unique combination of properties such as high electronic conductivity, and processability. These polymers/copolymers are nowadays tested/evaluated for antirust features on airplanes and helicopters. However, other electronic applications, such as photovoltaics, for transparent conductive polyaniline, actuators, for polypyrrole, and antistatic films, for polyEDOT, will be proposed.

  11. Polymers and radiation

    International Nuclear Information System (INIS)

    Zagorski, Z.

    2000-01-01

    The article is the broad review of history and state of art in radiation chemistry of polymers. The scientific background of radiation interaction with polymers and mechanisms of radiolytic degradation for aqueous solutions and 'dry' state of polymers have been shown. Also the applications of radiation for polymer properties modifications has been discussed in terms of polymers grafting and cross-linking for achieve shape memory feature, preparation of radioresistant polymers used for medical supplies being devoted to radiation sterilization etc. The polish contribution in related studies has been presented as well

  12. Conducting polymer materials

    Directory of Open Access Journals (Sweden)

    Jovanović Slobodan M.

    2003-01-01

    Full Text Available Conducting polymers represent a very interesting group of polymer materials Investigation of the synthesis, structure and properties of these materials has been the subject of considerable research efforts in the last twenty years. A short presentating of newer results obtained by investigating of the synthesis, structure and properties of two basic groups of conducting polymers: a conducting polymers the conductivity of which is the result of their molecular structure, and b conducting polymer composites (EPC, is given in this paper. The applications and future development of this group of polymer materials is also discussed.

  13. Silks as ancient models for modern polymers

    OpenAIRE

    Vollrath, Fritz; Porter, David

    2009-01-01

    Silks have a great potential as sustainable, ecologically benign commercial polymers. Here we discuss this fascinating bio-material by merging the biologist's with the polymer scientist's views i.e. combine insights into the characterisation and understanding of evolved structure, property and function in natural silk proteins with the broad scope of applied disciplines ranging from molecular modelling to rheology and mechanical testing. We conclude that silk cannot be defined simply by only ...

  14. Introduction to Polymer Chemistry.

    Science.gov (United States)

    Harris, Frank W.

    1981-01-01

    Reviews the physical and chemical properties of polymers and the two major methods of polymer synthesis: addition (chain, chain-growth, or chain-reaction), and condensation (step-growth or step-reaction) polymerization. (JN)

  15. Antiviral Polymer Therapeutics

    DEFF Research Database (Denmark)

    Smith, Anton Allen Abbotsford

    2014-01-01

    polymerized in a controlled manner with carrier monomers of historically proven biocompatible polymers. The carrier polymers, the loading of ribavirin as well as the size of the polymer were varied systematically with the aid of an automated synthesis platform. These polymers were tested in a cellular assay...... of reversible-addition-fragmentation chain transfer polymerization, which not only controls the size of polymer, but also allows the introduction of a terminal amine on the polymer which can be used for further conjugation. This has allowed for not only fluorescent labeling of the polymer, but also protein......The field of drug delivery is in essence an exercise in engineered pharmacokinetics. Methods of doing so have been developed through the introduction of a vehicle carrying the drug, either by encapsulation or covalent attachment. The emergence of polymer therapeutics in anticancer therapy has...

  16. Polymer Fluid Dynamics.

    Science.gov (United States)

    Bird, R. Byron

    1980-01-01

    Problems in polymer fluid dynamics are described, including development of constitutive equations, rheometry, kinetic theory, flow visualization, heat transfer studies, flows with phase change, two-phase flow, polymer unit operations, and drag reduction. (JN)

  17. Polymer dynamics from synthetic polymers to proteins

    Indian Academy of Sciences (India)

    Starting from the standard model of polymer motion - the Rouse model - we briefly present some key experimental results on the mesoscopic dynamics of polymer systems. We touch the role of topological confinement as expressed in the reptation model and discuss in some more detail processes limiting the confinement.

  18. Antimicrobial Modifications of Polymers

    OpenAIRE

    Sedlarik, Vladimir

    2013-01-01

    This chapter is focused on antimicrobial modifications of polymer materials intended for medical devices production. Firstly, a brief introduction into the field of medical application of polymers is presented. Considering the fact that polymer medical devices are often connected with occurrence of nosocomial infections, the next part refers to this phenomenon and its causes. One of the possibilities of reducing of the infection occurrence is aimed at polymer modification. It is a key topic o...

  19. Surface functionalized SiO2nanoparticles with cationic polymers via the combination of mussel inspired chemistry and surface initiated atom transfer radical polymerization: Characterization and enhanced removal of organic dye.

    Science.gov (United States)

    Huang, Qiang; Liu, Meiying; Mao, Liucheng; Xu, Dazhuang; Zeng, Guangjian; Huang, Hongye; Jiang, Ruming; Deng, Fengjie; Zhang, Xiaoyong; Wei, Yen

    2017-08-01

    Monodispersed SiO 2 particles functionalized with cationic polymers poly-((3-acrylamidopropyl)trimethylammonium chloride) (PAPTCl) were prepared using mussel inspired surface modification strategy and surface initiated atom transfer radical polymerization (SI-ATRP). Fourier transform infrared spectroscopy, transmission electron microscope, thermogravimetric analysis, X-ray photoelectron spectroscopy, and zeta potential were employed to characterize these SiO 2 samples. The adsorption performance of the functionalized SiO 2 (donated as SiO 2 -PDA-PAPTCl) towards anionic organic dye Congo red (CR) was investigated to evaluate their potential environmental applications. We demonstrated that the surface of SiO 2 particles can be successfully functionalized with cationic PAPTCl. The adsorption capability of as-prepared SiO 2 was found to increases from 28.70 and 106.65mg/g after surface grafted with cationic polymers. The significant enhancement in the adsorption capability of SiO 2 -PDA-PAPTCl is mainly attributed to the introduction of cationic polymers. More importantly, this strategy is expected to be promising for fabrication of many other functional polymer nanocomposites for environmental applications due to the universality of mussel inspired chemistry and well designability and good monomer adaptability of SI-ATRP. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Modeling semiflexible polymer networks

    NARCIS (Netherlands)

    Broedersz, C.P.; MacKintosh, F.C.

    2014-01-01

    This is an overview of theoretical approaches to semiflexible polymers and their networks. Such semiflexible polymers have large bending rigidities that can compete with the entropic tendency of a chain to crumple up into a random coil. Many studies on semiflexible polymers and their assemblies have

  1. Polymer-Graphene Nanocomposite Materials for Electrochemical Biosensing.

    Science.gov (United States)

    Sobolewski, Peter; Piwowarczyk, Magdalena; Fray, Mirosława El

    2016-07-01

    Biosensing is an important and rapidly developing field, with numerous potential applications in health care, food processing, and environmental control. Polymer-graphene nanocomposites aim to leverage the unique, attractive properties of graphene by combining them with those of a polymer matrix. Molecular imprinted polymers, in particular, offer the promise of artificial biorecognition elements. A variety of polymers, including intrinsically conducting polymers (polyaniline, polypyrrole), bio-based polymers (chitosan, polycatechols), and polycationic polymers (poly(diallyldimethylammonium chloride), polyethyleneimine), have been utilized as matrices for graphene-based nanofillers, yielding sensitive biosensors for various biomolecules, such as proteins, nucleic acids, and small molecules. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Electroassembly of smart polymer structures (role of polyelectrolytes)

    Science.gov (United States)

    Wallace, Gordon G.; Adeloju, Samuel B.; Shaw, Shannon J.

    1997-02-01

    Polymers are ubiquitous in nature, owing to their use as both structural and active components in dynamic, living systems. From a synthetic point of view man has utilized the excellent structural properties of polymers (light weight/high strength) for some decades now. However, the integration of active functional polymers into engineered systems and structures is a more recent endeavour with numerous challenges still to be overcome. Conducting electroactive polymers such as polypyrroles, polythiophenes and polyanilines are a fascinating group of functional polymers. They are electronic conductors and in addition they response to chemical or electrical stimuli in a number of ways. They are truly electrofunctional polymers. This unique combination of properties has led to the use of conducting polymers for electronic components, chemical sensors and biosensors, membranes for solution or gas separations, electromechanical actuators, electro-optical devices, biomaterials capable of controlled release of drugs or stimulation of biological processes, and for corrosion protection.

  3. Electroluminescence of Multicomponent Conjugated Polymers. 1. Roles of Polymer/Polymer Interfaces in Emission Enhancement and Voltage-Tunable Multicolor Emission in Semiconducting Polymer/Polymer Heterojunctions

    National Research Council Canada - National Science Library

    Zhang, Xuejun, Ph.D

    1999-01-01

    Effects of the electronic structure of polymer/polymer interfaces on the electroluminescence efficiency and tunable multicolor emission of polymer heterojunction light-emitting diodes were explored...

  4. Nanoporous polymer electrolyte

    Science.gov (United States)

    Elliott, Brian [Wheat Ridge, CO; Nguyen, Vinh [Wheat Ridge, CO

    2012-04-24

    A nanoporous polymer electrolyte and methods for making the polymer electrolyte are disclosed. The polymer electrolyte comprises a crosslinked self-assembly of a polymerizable salt surfactant, wherein the crosslinked self-assembly includes nanopores and wherein the crosslinked self-assembly has a conductivity of at least 1.0.times.10.sup.-6 S/cm at 25.degree. C. The method of making a polymer electrolyte comprises providing a polymerizable salt surfactant. The method further comprises crosslinking the polymerizable salt surfactant to form a nanoporous polymer electrolyte.

  5. Radiation effects on polymers

    International Nuclear Information System (INIS)

    Clough, R.L.; Shalaby, S.W.

    1991-01-01

    This book covers polymer radiation effects to be available in more than a decade. This volume reviews the fundamental chemistry and physics of polymer-radiation interaction and examines recent progress in most major areas of the field. Its 38 chapters, cover: fundamentals of polymer radiation chemistry; technological applications of radiation to polymers (including radiation processing; radiation curing; sterilization; cross-linking, polymerization, grafting, x-ray resists, and others); and degradation of stabilization of irradiated polymers (including nuclear plants, scintillation detectors for particle physics, and others)

  6. Biostable glucose permeable polymer

    DEFF Research Database (Denmark)

    2017-01-01

    A new biostable glucose permeable polymer has been developed which is useful, for example, in implantable glucose sensors. This biostable glucose permeable polymer has a number of advantageous characteristics and, for example, does not undergo hydrolytic cleavage and degradation, thereby providing...... a composition that facilitates long term sensor stability in vivo. The versatile characteristics of this polymer allow it to be used in a variety of contexts, for example to form the body of an implantable glucose sensor. The invention includes the polymer composition, sensor systems formed from this polymer...

  7. Polymer friction Molecular Dynamics

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, Vladimir N.; Persson, Bo N. J.

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: a) polymer sliding against a hard substrate, and b) polymer sliding on polymer. In the first setup the shear stresses are relatively...... independent of molecular length. For polymer sliding on polymer the friction is significantly larger, and dependent on the molecular chain length. In both cases, the shear stresses are proportional to the squeezing pressure and finite at zero load, indicating an adhesional contribution to the friction force....

  8. Suspensions of polymer-grafted nanoparticles with added polymers-Structure and effective pair-interactions.

    Science.gov (United States)

    Chandran, Sivasurender; Saw, Shibu; Kandar, A K; Dasgupta, C; Sprung, M; Basu, J K

    2015-08-28

    We present the results of combined experimental and theoretical (molecular dynamics simulations and integral equation theory) studies of the structure and effective interactions of suspensions of polymer grafted nanoparticles (PGNPs) in the presence of linear polymers. Due to the absence of systematic experimental and theoretical studies of PGNPs, it is widely believed that the structure and effective interactions in such binary mixtures would be very similar to those of an analogous soft colloidal material-star polymers. In our study, polystyrene-grafted gold nanoparticles with functionality f = 70 were mixed with linear polystyrene (PS) of two different molecular weights for obtaining two PGNP:PS size ratios, ξ = 0.14 and 2.76 (where, ξ = Mg/Mm, Mg and Mm being the molecular weights of grafting and matrix polymers, respectively). The experimental structure factor of PGNPs could be modeled with an effective potential (Model-X), which has been found to be widely applicable for star polymers. Similarly, the structure factor of the blends with ξ = 0.14 could be modeled reasonably well, while the structure of blends with ξ = 2.76 could not be captured, especially for high density of added polymers. A model (Model-Y) for effective interactions between PGNPs in a melt of matrix polymers also failed to provide good agreement with the experimental data for samples with ξ = 2.76 and high density of added polymers. We tentatively attribute this anomaly in modeling the structure factor of blends with ξ = 2.76 to the questionable assumption of Model-X in describing the added polymers as star polymers with functionality 2, which gets manifested in both polymer-polymer and polymer-PGNP interactions especially at higher fractions of added polymers. The failure of Model-Y may be due to the neglect of possible many-body interactions among PGNPs mediated by matrix polymers when the fraction of added polymers is high. These observations point to the need for a new framework to

  9. The role of hydrogen bonding in tethered polymer layers

    OpenAIRE

    Ren, C.; Nap, R. J.; Szleifer, I.

    2008-01-01

    A molecular theory to study the properties of end tethered polymer layers, in which the polymers have the ability to form hydrogen bonds with water is presented. The approach combines the ideas of the single-chain mean-field theory to treat tethered layers with the approach of Dormidontova (Macromolecules, 2002 35,987) to include hydrogen bonds. The generalization includes the consideration of position dependent polymer-water and water-water hydrogen bonds. The theory is applied to model poly...

  10. Physical and Electrical Characterization of Polymer Aluminum Capacitors

    Science.gov (United States)

    Liu, David; Sampson, Michael J.

    2010-01-01

    Polymer aluminum capacitors from several manufacturers with various combinations of capacitance, rated voltage, and ESR values were physically examined and electrically characterized. The physical construction analysis of the capacitors revealed three different capacitor structures, i.e., traditional wound, stacked, and laminated. Electrical characterization results of polymer aluminum capacitors are reported for frequency-domain dielectric response at various temperatures, surge breakdown voltage, and other dielectric properties. The structure-property relations in polymer aluminum capacitors are discussed.

  11. Physical and Electrical Characterization of Aluminum Polymer Capacitors

    Science.gov (United States)

    Liu, David; Sampson, Michael J.

    2010-01-01

    Polymer aluminum capacitors from several manufacturers with various combinations of capacitance, rated voltage, and ESR values were physically examined and electrically characterized. The physical construction analysis of the capacitors revealed three different capacitor structures, i.e., traditional wound, stacked, and laminated. Electrical characterization results of polymer aluminum capacitors are reported for frequency-domain dielectric response at various temperatures, surge breakdown voltage, and other dielectric properties. The structure-property relations in polymer aluminum capacitors are discussed.

  12. Functional supramolecular polymers for biomedical applications.

    Science.gov (United States)

    Dong, Ruijiao; Zhou, Yongfeng; Huang, Xiaohua; Zhu, Xinyuan; Lu, Yunfeng; Shen, Jian

    2015-01-21

    As a novel class of dynamic and non-covalent polymers, supramolecular polymers not only display specific structural and physicochemical properties, but also have the ability to undergo reversible changes of structure, shape, and function in response to diverse external stimuli, making them promising candidates for widespread applications ranging from academic research to industrial fields. By an elegant combination of dynamic/reversible structures with exceptional functions, functional supramolecular polymers are attracting increasing attention in various fields. In particular, functional supramolecular polymers offer several unique advantages, including inherent degradable polymer backbones, smart responsiveness to various biological stimuli, and the ease for the incorporation of multiple biofunctionalities (e.g., targeting and bioactivity), thereby showing great potential for a wide range of applications in the biomedical field. In this Review, the trends and representative achievements in the design and synthesis of supramolecular polymers with specific functions are summarized, as well as their wide-ranging biomedical applications such as drug delivery, gene transfection, protein delivery, bio-imaging and diagnosis, tissue engineering, and biomimetic chemistry. These achievements further inspire persistent efforts in an emerging interdisciplin-ary research area of supramolecular chemistry, polymer science, material science, biomedical engineering, and nanotechnology. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Fluorination of polymers

    International Nuclear Information System (INIS)

    Du Toit, F.J.

    1991-01-01

    Polyethylene and polypropylene were reacted with elemental fluorine under carefully controlled conditions to produce fluorocarbon polymers. Fluorination of polymer films resulted in fluorination of only the outer surfaces of the films, while the reaction of elemental fluorine with powdered hydrocarbon polymers produced perfluorocarbon polymers. Existing and newly developed techniques were used to characterize the fluorinated polymers. It was shown that the degree of fluorination was influenced by the surface area of the hydrocarbon material, the concentration, of the fluorine gas, and the time and temperature of fluorination. A fluidized-bed reactor used for the fluorination of polymer powders effectively increased the reaction rate. The surface tension and the oxygen permeability of the fluorinated polymers were studied. The surface tension of hydrocarbon polymers was not influenced by different solvents, but the surface tension of fluorinated polymers was affected by the type of solvent that was used. There were indications that the surface tension was affected by oxygen introduced into the polymer surface during fluorination. Fluorination lowered the permeability of oxygen through hydrocarbon polymers. 55 refs., 51 figs., 26 tabs

  14. Advanced polymers in medicine

    CERN Document Server

    Puoci, Francesco

    2014-01-01

    The book provides an up-to-date overview of the diverse medical applications of advanced polymers. The book opens by presenting important background information on polymer chemistry and physicochemical characterization of polymers. This serves as essential scientific support for the subsequent chapters, each of which is devoted to the applications of polymers in a particular medical specialty. The coverage is broad, encompassing orthopedics, ophthalmology, tissue engineering, surgery, dentistry, oncology, drug delivery, nephrology, wound dressing and healing, and cardiology. The development of polymers that enhance the biocompatibility of blood-contacting medical devices and the incorporation of polymers within biosensors are also addressed. This book is an excellent guide to the recent advances in polymeric biomaterials and bridges the gap between the research literature and standard textbooks on the applications of polymers in medicine.

  15. Polymer powders for selective laser sintering (SLS)

    Science.gov (United States)

    Schmid, Manfred; Amado, Antonio; Wegener, Konrad

    2015-05-01

    Selective Laser Sintering (SLS) is close to be accepted as a production technique (Additive Manufacturing). However, one problem limiting employment of SLS for additive manufacturing in a wide-ranging industrial scope is the narrow variety of applicable polymers. The commonly applied SLS powder to date is polyamide 12 (PA 12). PA 12 or ccompounds of PA 12 (dry blends) are approximately 90 % of complete industrial consumption. The remaining small quantity is distributed on polyamide 11 (PA11) and some other `exotic' polymers (TPU, PEBA, P(E)EK). Industry is awaiting commodity polymers like polypropylene (PP) or polyethylene (PE) crucial to open new market segments. But several approaches launching those polymers failed. But what are the reasons for the difficulties in developing new SLS powders? The contribution is to answer this and highlights the combination of intrinsic and extrinsic polymer properties necessary to generate a polymer powder promising for SLS application. Particle shape, powder distribution, thermal, rheological and optical requirements must be considered and only a particularly controlled property combination leads to successful SLS implementation. Thermal behavior, particle shape and -distribution is discussed in detail, although the other properties can't be disregarded for providing new commercially successful SLS powder finally.

  16. Inorganic and organometallic polymers: A review

    International Nuclear Information System (INIS)

    Rahimi, Azam

    2004-01-01

    Inorganic polymeric materials comprise a very unique area science. These macromolecules which contain inorganic elements as part of their main chain structure or as pendent group, attract considerable attention as sceptically materials with unique properties and novel applications. Two main classes of these compounds: in organic and organometallic polymers, which represent a growing field of research, have found broad diverse applications. As, organic components with countless combinations are found in these classes of polymers they offer a wide range of interesting properties and applications. In this paper, the main properties of some more important classes of these compounds, including wholly inorganic-organic polymers, organometallic polymers and hybrid organic-inorganic networks are discussed on the basis of their structural features, and some examples of the novel applications of these materials are presented

  17. Fabrication of silicon molds for polymer optics

    DEFF Research Database (Denmark)

    Nilsson, Daniel; Jensen, Søren; Menon, Aric Kumaran

    2003-01-01

    A silicon mold used for structuring polymer microcavities for optical applications is fabricated, using a combination of DRIE (deep reactive ion etching) and anisotropic chemical wet etching with KOH + IPA. For polymer optical microcavities, low surface roughness and vertical sidewalls are often...... needed. This is achieved by aligning the mold precisely to the [110] direction of a silicon (100) wafer and etching very close to the (110) surfaces using a DRIE Bosch process. The surface roughness of the sidewalls is then removed with a short etch in KOH + IPA. To achieve this, the parameters for DRIE...... and KOH + IPA etch have been optimized. To reduce stiction between the silicon mold and the polymers used for molding, the mold is coated with a teflon-like material using the DRIE system. Released polymer microstructures characterized with AFM and SEM are also presented....

  18. Chemistry of radiation degradation of polymers

    International Nuclear Information System (INIS)

    O'Donnell, J.H.

    1990-01-01

    High energy radiation produces ionization and excitation in polymer molecules. These energy-rich species undergo ionic combination and ion-molecule reactions resulting in further reactive intermediates for chemical change. Scission and crosslinking of the polymer molecules, formation of small molecular products and modification of the chemical structure of the polymer are responsible for the changes in material properties by radiation. The identification and measurement of these changes utilizing solution characterization methods, ESR spectroscopy of radical intermediates and NMR spectroscopy of chemical structure are considered. These radiation chemical yields of the different types of degradation assist in understanding the mechanism of radiation degradation. Relationships between the chemical structure of the polymer and the radiation sensitivity/resistance are considered

  19. Water-Soluble Metallocene-Containing Polymers.

    Science.gov (United States)

    Alkan, Arda; Wurm, Frederik R

    2016-09-01

    Metallocenes are organometallic compounds with reversible redox profiles and tunable oxidation and reduction potentials, depending on the metal and substituents at the cyclopentadienyl rings. Metallocenes have been introduced in macromolecules to combine the redox-activity with polymer properties. There are many examples of such hydrophobic polymer materials, but much fewer water-soluble examples are found scattered across the polymer literature. However, in terms of drug delivery and other biological applications, water solubility is essential. For this very reason, all the synthetic routes to water-soluble metallocene containing polymers are collected and discussed here. The focus is on neutral ferrocene- and ruthenocene-containing and charged cobaltocenium-containing macromolecules (i.e., symmetrical sandwich complexes). The synthetic protocols, self-assembly behavior, and other benefits of the obtained materials are discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. High temperature performance of polymer composites

    CERN Document Server

    Keller, Thomas

    2014-01-01

    The authors explain the changes in the thermophysical and thermomechanical properties of polymer composites under elevated temperatures and fire conditions. Using microscale physical and chemical concepts they allow researchers to find reliable solutions to their engineering needs on the macroscale. In a unique combination of experimental results and quantitative models, a framework is developed to realistically predict the behavior of a variety of polymer composite materials over a wide range of thermal and mechanical loads. In addition, the authors treat extreme fire scenarios up to more than 1000°C for two hours, presenting heat-protection methods to improve the fire resistance of composite materials and full-scale structural members, and discuss their performance after fire exposure. Thanks to the microscopic approach, the developed models are valid for a variety of polymer composites and structural members, making this work applicable to a wide audience, including materials scientists, polymer chemist...

  1. Flow NMR of polymers in external fields

    Energy Technology Data Exchange (ETDEWEB)

    Boehme, Ute; Bagusat, Frank; Scheler, Ulrich [Leibniz Institute of Polymer Research Dresden (Germany)

    2008-07-01

    Pulsed-field gradient NMR is applied to study the motion of polymers in an external electric field and under mechanical shear. The application of an electric field drives motion of charged species. In conjunction with the diffusion coefficient from the electrophoretic mobility the effective charge per molecule is derived. The electric field applicable in the aqueous system is too weak to deform the polymer or even abstract counterions. In a shear flow established in a Couette cell partial orientation of polymer chains is measured via residual dipolar couplings. The entire flow field in a non-symmetric flow cell is monitored by a combination of PFG NMR and NMR imaging exhibiting regions of high shear and locally low shear, where polymers relax.

  2. Water evaporation on highly viscoelastic polymer surfaces.

    Science.gov (United States)

    Pu, Gang; Severtson, Steven J

    2012-07-03

    Results are reported for a study on the evaporation of water droplets from a highly viscoelastic acrylic polymer surface. These are contrasted with those collected for the same measurements carried out on polydimethylsiloxane (PDMS). For PDMS, the evaporation process involves the expected multistep process including constant drop area, constant contact angle, and finally a combination of these steps until the liquid is gone. In contrast, water evaporation from the acrylic polymer shows a constant drop area mode throughout. Furthermore, during the evaporation process, the drop area actually expands on the acrylic polymer. The single mode evaporation process is consistent with formation of wetting structures, which cannot be propagated by the capillary forces. Expansion of the drop area is attributed to the influence of the drop capillary pressure. Furthermore, the rate of drop area expansion is shown to be dependent on the thickness of the polymer film.

  3. Colloidal QDs-polymer nanocomposites

    Science.gov (United States)

    Gordillo, H.; Suárez, I.; Rodríguez-Cantó, P.; Abargues, R.; García-Calzada, R.; Chyrvony, V.; Albert, S.; Martínez-Pastor, J.

    2012-04-01

    Nanometer-size colloidal semiconductor nanocrystals, or Quantum Dots (NQD), are very prospective active centers because their light emission is highly efficient and temperature-independent. Nanocomposites based on the incorporation of QDs inside a polymer matrix are very promising materials for application in future photonic devices because they combine the properties of QDs with the technological feasibility of polymers. In the present work some basic applications of these new materials have been studied. Firstly, the fabrication of planar and linear waveguides based on the incorporation of CdS, CdSe and CdTe in PMMA and SU-8 are demonstrated. As a result, photoluminescence (PL) of the QDs are coupled to a waveguide mode, being it able to obtain multicolor waveguiding. Secondly, nanocomposite films have been evaluated as photon energy down-shifting converters to improve the efficiency of solar cells.

  4. Construction of polymer-protein bioconjugates with varying chain topologies: polymer molecular weight and steric hindrance effects.

    Science.gov (United States)

    Wan, Xuejuan; Zhang, Guoying; Ge, Zhishen; Narain, Ravin; Liu, Shiyong

    2011-10-04

    We report on the fabrication of well-defined polymer-protein bioconjugates with varying chain architectures, including star polymers, star block copolymers, and heteroarm star copolymers through the specific noncovalent interaction between avidin and biotinylated synthetic polymer precursors. Homopolymer and diblock precursors site-specifically labeled with a single biotin moiety at the chain terminal, chain middle, or diblock junction point were synthesized by a combination of atom-transfer radical polymerization (ATRP) and click reactions. By taking advantage of molecular recognition between avidin and biotin moieties, supramolecular star polymers, star block copolymers, and heteroarm star copolymers were successfully fabricated. This specific binding process was also assessed by using the diffraction optic technology (DOT) technique. We further investigated the effects of polymer molecular weights, location of biotin functionality within the polymer chain, and polymer chain conformations, that is, steric hindrance effects, on the binding numbers of biotinylated polymer chains per avidin within the polymer-protein bioconjugates, which were determined by the standard avidin/2-(4-hydroxyazobenzene)benzoic acid (HABA) assay. The binding numbers vary in the range of 1.9-3.3, depending on the molecular weights, locations of biotin functionality within synthetic polymer precursors, and polymer chain conformations. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Stratification in Drying Polymer-Polymer and Colloid-Polymer Mixtures.

    Science.gov (United States)

    Howard, Michael P; Nikoubashman, Arash; Panagiotopoulos, Athanassios Z

    2017-10-24

    Drying polymer-polymer and colloid-polymer mixtures were studied using Langevin dynamics computer simulations. Polymer-polymer mixtures vertically stratified into layers, with the shorter polymers enriched near the drying interface and the longer polymers pushed down toward the substrate. Colloid-polymer mixtures stratified into a polymer-on-top structure when the polymer radius of gyration was comparable to or smaller than the colloid diameter, and a colloid-on-top structure otherwise. We also developed a theoretical model for the drying mixtures based on dynamical density functional theory, which gave excellent quantitative agreement with the simulations for the polymer-polymer mixtures and qualitatively predicted the observed polymer-on-top or colloid-on-top structures for the colloid-polymer mixtures.

  6. STUDIES OF DRUG-POLYMER INTERACTIONS OF SIMVASTATIN WITH VARIOUS POLYMERS

    OpenAIRE

    Trishna Bal et al.

    2012-01-01

    The purpose of the present study is to prepare different combinations of drug Simvastatin (SV) with different polymers like Sodium alginate (SA), Hydroxypropylmethylcellulose (HPMC), Pectin (P), Dillenia (D) and Hydroxy propyl β- cyclodextrin. (HPC), thereby determine and report any possible interactions between the drug Simvastatin (SV) and various polymers both from natural and synthetic sources. The natural plant fruit seed mucilage Dillenia(D) was extracted from the plant Dillenia indica ...

  7. Star-Branched Polymers (Star Polymers)

    KAUST Repository

    Hirao, Akira

    2015-09-01

    The synthesis of well-defined regular and asymmetric mixed arm (hereinafter miktoarm) star-branched polymers by the living anionic polymerization is reviewed in this chapter. In particular, much attention is being devoted to the synthetic development of miktoarm star polymers since 2000. At the present time, the almost all types of multiarmed and multicomponent miktoarm star polymers have become feasible by using recently developed iterative strategy. For example, the following well-defined stars have been successfully synthesized: 3-arm ABC, 4-arm ABCD, 5-arm ABCDE, 6-arm ABCDEF, 7-arm ABCDEFG, 6-arm ABC, 9-arm ABC, 12-arm ABC, 13-arm ABCD, 9-arm AB, 17-arm AB, 33-arm AB, 7-arm ABC, 15-arm ABCD, and 31-arm ABCDE miktoarm star polymers, most of which are quite new and difficult to synthesize by the end of the 1990s. Several new specialty functional star polymers composed of vinyl polymer segments and rigid rodlike poly(acetylene) arms, helical polypeptide, or helical poly(hexyl isocyanate) arms are introduced.

  8. Photoluminescence of conjugated polymer blends at the nanoscale

    NARCIS (Netherlands)

    Jarzab, D.; Lu, M.; Nicolai, H.T.; Blom, P.W.M.; Loi, M.A.

    2011-01-01

    Here we report on a combined photoluminescence and morphological study of a polymer-polymer blend composed of a copolymer of derivatives of polyspirobifluorene and polyfluorene (PBFF) and a derivative of polyphenylene vinylene (MDMO-PPV). Evidence of partial Förster energy transfer from PBFF to

  9. Organometallic polymers for electrode decoration in sensing applications

    NARCIS (Netherlands)

    Feng, Xueling; Zhang, Kaihuan; Hempenius, Mark A.; Vancso, Gyula J.

    2015-01-01

    Macromolecules containing metals combine the processing advantages of polymers with the functionality offered by the metal centers. This review outlines the progress and recent developments in the area of electrochemical chemo/biosensors that are based on organometallic polymers. We focus on

  10. Phase behaviour of rod-like colloid + flexible polymer mixtures

    NARCIS (Netherlands)

    Lekkerkerker, H.N.W.; Stroobants, A.

    The effect of non-adsorbing, flexible polymer on the isotropic-nematic transition in dispersions of rod-like colloids is investigated. A widening of the biphasic gap is observed, in combination with a marked polymer partitioning between the coexisting phases. Under certain conditions, areas of

  11. Dynamics of competitive polymer adsorption onto planar surfaces in good solvent.

    Science.gov (United States)

    Källrot, Niklas; Linse, Per

    2010-03-25

    Adsorption of mixed polymer solutions in good solvent containing polymers of different chain length has been studied by applying simulation techniques on a coarse-grained bead-spring polymer model. Fully flexible polymers at varying bead-surface interaction strength and different combinations of flexible, semiflexible, and stiff polymers at a single bead-surface interaction strength have been examined. Monte Carlo simulation techniques have been employed to investigate static equilibrium properties and Brownian dynamic simulations to follow the dynamics of the adsorption process. The properties examined comprise the adsorbed number of polymers, adsorbed number of beads, bead density profiles, components of the polymer radius of gyration, tail, loop, and train configurations, and nematic bond order of adsorbed beads. The adsorption involves an initially independent adsorption of the two polymer types followed by competitive adsorption. The competitive adsorption is characterized by a maximum of the adsorbed amount and a desorption of the polymer with the smallest surface affinity and a continued, but reduced, growth of the adsorbed amount of the polymer with the largest surface affinity. The surface affinity difference between the two polymer types of different length increased with increasing bead-surface interaction. Furthermore, the surface affinity of a polymer initially decreased but then largely increased at increasing stiffness. As a consequence, a stiff short polymer was found to displace a 4-fold longer flexible polymer. The spatial extension of adsorbed polymers as characterized by the radius of gyration parallel and perpendicular to the surface of a polymer of a given flexibility was independent of the flexibility of the other polymer type. The fraction of beads in tails was increased and in trains reduced as the surface affinity of the dissimilar polymer type was raised. Finally, the adsorption layer of a stiff polymer possesses a nematic bond order. In

  12. Artificially Engineered Protein Polymers.

    Science.gov (United States)

    Yang, Yun Jung; Holmberg, Angela L; Olsen, Bradley D

    2017-06-07

    Modern polymer science increasingly requires precise control over macromolecular structure and properties for engineering advanced materials and biomedical systems. The application of biological processes to design and synthesize artificial protein polymers offers a means for furthering macromolecular tunability, enabling polymers with dispersities of ∼1.0 and monomer-level sequence control. Taking inspiration from materials evolved in nature, scientists have created modular building blocks with simplified monomer sequences that replicate the function of natural systems. The corresponding protein engineering toolbox has enabled the systematic development of complex functional polymeric materials across areas as diverse as adhesives, responsive polymers, and medical materials. This review discusses the natural proteins that have inspired the development of key building blocks for protein polymer engineering and the function of these elements in material design. The prospects and progress for scalable commercialization of protein polymers are reviewed, discussing both technology needs and opportunities.

  13. Internally plasticised cellulose polymers

    International Nuclear Information System (INIS)

    Burnup, M.; Hayes, G.F.; Fydelor, P.J.

    1981-01-01

    Plasticised cellulose polymers comprise base polymer having a chain of β-anhydroglucose units joined by ether linkages, with at least one of said units carrying at least one chemically unreactive side chain derived from an allylic monomer or a vinyl substituted derivative of ferrocene. The side chains are normally formed by radiation grafting. These internally plasticised celluloses are useful in particular as inhibitor coatings for rocket motor propellants and in general wherever cellulose polymers are employed. (author)

  14. Characterisation of polymers, 1

    CERN Document Server

    Crompton, Roy

    2008-01-01

    This essential guide to Polymer Characterisation is a complete compendium of methodologies that have evolved for the determination of the chemical composition of polymers. This 478-page book gives an up-to-date and thorough exposition of the state-of-the-art theories and availability of instrumentation needed to effect chemical and physical analysis of polymers. This is supported by approximately 1200 references. Volume 1 covers the methodology used for the determination of metals, non-metals and organic functional groups in polymers, and for the determination of the ratio in which different m

  15. Interest of neutron scattering for the investigation of liquid-crystalline polymers

    International Nuclear Information System (INIS)

    Noirez, L.

    1994-01-01

    Small-angle Neutron scattering is the unique method which allows the determination of polymer conformation in the bulk state. This method has been applied to several kinds of liquid crystalline polymers. Results concerning side-chain liquid-crystal polymer, main-chain liquid-crystal polymer and combined liquid-crystal polymers, are reported. It is shown that the polymer conformation is largely dependent on the insertion site of the liquid crystal molecule and of the structure of the meso-phase. (author). 11 refs

  16. Probing surfaces with single-polymer atomic force microscope experiments.

    Science.gov (United States)

    Friedsam, C; Gaub, H E; Netz, R R

    2006-03-01

    In the past 15 years atomic force microscope (AFM) based force spectroscopy has become a versatile tool to study inter- and intramolecular interactions of single polymer molecules. Irreversible coupling of polymer molecules between the tip of an AFM cantilever and the substrate allows one to study the stretching response up to the high force regime of several nN. For polymers that glide or slip laterally over the surface with negligible friction, on the other hand, the measured force profiles exhibit plateaus which allow one to extract the polymer adsorption energies. Long-term stable polymer coatings of the AFM tips allow for the possibility of repeating desorption experiments from solid supports with individual molecules many times, yielding good sampling statistics and thus reliable estimates for adsorption energies. In combination with recent advances in theoretical modeling, a detailed picture of the conformational statistics, backbone elasticity, and the adsorption characteristics of single polymer molecules is obtained.

  17. Polymers and Dyes: Developments and Applications

    Directory of Open Access Journals (Sweden)

    Carolin Fleischmann

    2015-04-01

    Full Text Available Amongst functional macromolecules, the combination of polymers and dyes is a research field of great potential with regard to high-performance materials. Accordingly, colored polymers have become increasingly important as materials for miscellaneous technical applications in recent years while also being a major part of everyday life. For instance, dye-containing polymers are nowadays widely applied in medicine, painting industries, analytics and gas separation processes. Since these applications are obviously connected to the dye’s nature, which is incorporated into the corresponding polymers, the affinity of certain polymers to dyes is exploited in wastewater work-ups after (textile dyeing procedures. In this review, we wish to point out the great importance of dye-containing polymers, with a comprehensive scope and a focus on azo, triphenylmethane, indigoid, perylene and anthraquinone dyes. Since a large number of synthetic approaches towards the preparation of such materials can be found in the literature, an elaborated overview of different preparation techniques is given as well.

  18. Novel Polymer Microfluidics Technology for In Situ Planetary Exploration, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Los Gatos Research proposes to develop a novel microfluidic device that combines rigid monolithic porous polymer based micro-capillary electrochromatography...

  19. Atomic Origins of the Self-Healing Function in Cement–Polymer Composites

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Manh Thuong; Wang, Zheming; Rod, Kenton A.; Childers, Matthew I.; Fernandez, Carlos A.; Koech, Phillip K.; Bennett, Wendy D.; Rousseau, Roger J.; Glezakou, Vassiliki-Alexandra

    2018-01-09

    Motivated by recent advances in self-healing cement and epoxy polymer composites, we present a combined ab initio molecular dynamics and sum frequency generation (SFG) spectroscopy study of a calcium-silicate-hydrate/polymer interface. On stable, low-defect surfaces, the polymer only weakly adheres through coordination and hydrogen bonding interactions and can be easily mobilized towards defected surfaces. Conversely, on fractured surfaces, the polymer strongly anchors through ionic Ca-O bonds resulting from the deprotonation of polymer hydroxyl groups. In addition, polymer S-S groups are turned away from the cement/polymer interface, allowing for the self-healing function within the polymer. The overall elasticity and healing properties of these composites stem from a flexible hydrogen bonding network that can readily adapt to surface morphology. The theoretical vibrational signals associated with the proposed cement-polymer interfacial chemistry were confirmed experimentally by SFG spectroscopy.

  20. Ultrasound-assisted combined with nano-sized molecularly imprinted polymer for selective extraction and pre-concentration of amitriptyline in human plasma with gas chromatography-flame detection.

    Science.gov (United States)

    Khanahmadzadeh, Salah; Tarigh, Ahmad

    2014-12-01

    A new process was developed for the selective extraction and pre-concentration of amitriptyline (AT) from human plasma using nano-sized molecularly imprinted polymer (MIP) with ultrasound-assisted extraction (UAE). The nano-sized AT imprinted polymer particles were synthesized using suspension polymerization in silicon oil and characterized by Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscope (SEM) methods. With the application of optimized values, linearity values in the ranges of 20-200μgmL(-1) and 35-200μgmL(-1) were obtained for AT with the correlation of determination values (r(2)) 0.998 and 0.995 in water and plasma, respectively. The limits of detections (S/N=3) for AT were found to be 0.7 and 1.2μgmL(-1) in water and plasma, respectively. The enrichment factors of AT in water and plasma were 52 and 40, respectively. The inter-day precisions (%) were in the range of 5.8-9.2%. Relative recovery rates ranged from 82.4% to 92.3%. The method was successfully applied to determine AT in the human plasma samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Role of Molecular Interactions for Synergistic Precipitation Inhibition of Poorly Soluble Drug in Supersaturated Drug-Polymer-Polymer Ternary Solution.

    Science.gov (United States)

    Prasad, Dev; Chauhan, Harsh; Atef, Eman

    2016-03-07

    We are reporting a synergistic effect of combined Eudragit E100 and PVP K90 in precipitation inhibition of indomethacin (IND) in solutions at low polymer concentration, a phenomenon that has significant implications on the usefulness of developing novel ternary solid dispersion of poorly soluble drugs. The IND supersaturation was created by cosolvent technique, and the precipitation studies were performed in the absence and the presence of individual and combined PVP K90 and Eudragit E100. The studies were also done with PEG 8000 as a noninteracting control polymer. A continuous UV recording of the IND absorption was used to observe changes in the drug concentration over time. The polymorphic form and morphology of precipitated IND were characterized by Raman spectroscopy and scanning electron microscopy. The change in the chemical shift in solution (1)H NMR was used as novel approach to probe IND-polymer interactions. Molecular modeling was used for calculating binding energy between IND-polymer as another indication of IND-polymer interaction. Spontaneous IND precipitation was observed in the absence of polymers. Eudragit E100 showed significant inhibitory effect on nuclei formation due to stronger interaction as reflected in higher binding energy and greater change in chemical shift by NMR. PVP K90 led to significant crystal growth inhibition due to adsorption on growing IND crystals as confirmed by modified crystal habit of precipitate in the presence of PVP K90. Combination of polymers resulted in a synergistic precipitation inhibition and extended supersaturation. The NMR confirmed interaction between IND-Eudragit E100 and IND-PVP K90 in solution. The combination of polymers showed similar peak shift albeit using lower polymer concentration indicating stronger interactions. The results established the significant synergistic precipitation inhibition effect upon combining Eudragit E100 and PVP K90 due to drug-polymer interaction.

  2. Bridging polymer synthesis and ease in processing

    NARCIS (Netherlands)

    Romano, Dario

    2017-01-01

    High Performance polymeric materials are a subject of considerable interest due to their high mechanical performances when combined with their versatility in processing and synthesis. In order to achieve high mechanical properties, scientist focuses on increasing the molecular weight of the polymer

  3. Oriented nanofibers embedded in a polymer matrix

    Science.gov (United States)

    Barrera, Enrique V. (Inventor); Rodriguez-Macias, Fernando J. (Inventor); Lozano, Karen (Inventor); Chibante, Luis Paulo Felipe (Inventor); Stewart, David Harris (Inventor)

    2011-01-01

    A method of forming a composite of embedded nanofibers in a polymer matrix is disclosed. The method includes incorporating nanofibers in a plastic matrix forming agglomerates, and uniformly distributing the nanofibers by exposing the agglomerates to hydrodynamic stresses. The hydrodynamic said stresses force the agglomerates to break apart. In combination or additionally elongational flow is used to achieve small diameters and alignment. A nanofiber reinforced polymer composite system is disclosed. The system includes a plurality of nanofibers that are embedded in polymer matrices in micron size fibers. A method for producing nanotube continuous fibers is disclosed. Nanofibers are fibrils with diameters of 100 nm, multiwall nanotubes, single wall nanotubes and their various functionalized and derivatized forms. The method includes mixing a nanofiber in a polymer; and inducing an orientation of the nanofibers that enables the nanofibers to be used to enhance mechanical, thermal and electrical properties. Orientation is induced by high shear mixing and elongational flow, singly or in combination. The polymer may be removed from said nanofibers, leaving micron size fibers of aligned nanofibers.

  4. Physical and Electrical Characterization of Aluminum Polymer Capacitors

    Science.gov (United States)

    Liu, David (Donghang)

    2010-01-01

    Conductive polymer aluminum capacitor (PA capacitor) is an evolution of traditional wet electrolyte aluminum capacitors by replacing liquid electrolyte with a solid, highly conductive polymer. On the other hand, the cathode construction in polymer aluminum capacitors with coating of carbon and silver epoxy for terminal connection is more like a combination of the technique that solid tantalum capacitor utilizes. This evolution and combination result in the development of several competing capacitor construction technologies in manufacturing polymer aluminum capacitors. The driving force of this research on characterization of polymer aluminum capacitors is the rapid progress in IC technology. With the microprocessor speeds exceeding a gigahertz and CPU current demands of 80 amps and more, the demand for capacitors with higher peak current and faster repetition rates bring conducting polymer capacitors to the center o( focus. This is because this type of capacitors has been known for its ultra-low ESR and high capacitance. Polymer aluminum capacitors from several manufacturers with various combinations of capacitance, rated voltage, and ESR values were obtained and tested. The construction analysis of the capacitors revealed three different constructions: conventional rolled foil, the multilayer stacking V-shape, and a dual-layer sandwich structure. The capacitor structure and its impact on the electrical characteristics has been revealed and evaluated. A destructive test with massive current over stress to fail the polymer aluminum capacitors reveals that all polymer aluminum capacitors failed in a benign mode without ignition, combustion, or any other catastrophic failures. The extraordinary low ESR (as low as 3 mOMEGA), superior frequency independence reported for polymer aluminum capacitors have been confirmed. For the applications of polymer aluminum capacitors in space programs, a thermal vacuum cycle test was performed. The results, as expected, show no

  5. Polymers targeting habitual diseases

    Science.gov (United States)

    The use of polymeric drug conjugates mainly for the treatment for cancer therapy has been addressed, but these polymers also find their way in treatment of various lifestyle disorders like diabetes, hypertension, cardiovascular diseases etc. The focus is being laid to develop biodegradable polymer ...

  6. Stiff Quantum Polymers

    OpenAIRE

    Kleinert, H.

    2007-01-01

    At ultralow temperatures, polymers exhibit quantum behavior, which is calculated here for the second and fourth moments of the end-to-end distribution in the large-stiffness regime. The result should be measurable for polymers in wide optical traps.

  7. Segmented conjugated polymers

    Indian Academy of Sciences (India)

    Segmented conjugated polymers, wherein the conjugation is randomly truncated by varying lengths of non-conjugated segments, form an interesting class of polymers as they not only represent systems of varying stiffness, but also ones where the backbone can be construed as being made up of chromophores of varying ...

  8. Elastic lattice polymers

    NARCIS (Netherlands)

    Baiesi, M.; Barkema, G.T.; Carlon, E.

    2010-01-01

    We study a model of “elastic” lattice polymer in which a fixed number of monomers m is hosted by a self-avoiding walk with fluctuating length l. We show that the stored length density m 1− l /m scales asymptotically for large m as m= 1− /m+. . . , where is the polymer entropic exponent, so that can

  9. Polymer gels and networks

    National Research Council Canada - National Science Library

    Osada, Yoshihito; Khokhlov, A. R

    2002-01-01

    ... or magnetic field, etc.). It was realized that not only can polymer gels absorb and hold a considerable volume of liquids, but they can also be forced to expel the absorbed liquid in a controlled manner. Of particular interest are hydrogels, i.e., polymer gels, which swell extensively in water. The most common hydrogels are polyelectrolyte gels: ...

  10. Polymer light emitting diodes

    International Nuclear Information System (INIS)

    Gautier-Thianche, Emmmanuelle

    1998-01-01

    We study sandwich type semiconducting polymer light emitting diodes; anode/polymer/cathode. ITO is selected as anode, this polymer is a blend of a commercially available polymer with a high hole transport ability: polyvinyl-carbazole and a laser dye: coumarin-515. Magnesium covered with silver is chosen for the anode. We study the influence of polymer thickness and coumarin doping ratio on electroluminescence spectrum, electric characteristics and quantum efficiency. An important drawback is that diodes lifetime remains low. In the second part of our study we determine degradations causes with X-Ray reflectivity experiments. It may be due to ITO very high roughness. We realize a new type of planar electroluminescent device: a channel type electroluminescent device in which polymer layer is inserted into an aluminium channel. Such a device is by far more stable than using classical sandwich structures with the same polymer composition: indeed, charges are generated by internal-field ionization and there is no injection from the electrode to the polymer. This avoids electrochemical reactions at electrodes, thus reducing degradations routes. (author) [fr

  11. Polymers for Combating Biocorrosion

    Directory of Open Access Journals (Sweden)

    Jing Guo

    2018-03-01

    Full Text Available Biocorrosion has been considered as big trouble in many industries and marine environments due to causing of great economic loss. The main disadvantages of present approaches to prevent corrosion include being limited by environmental factors, being expensive, inapplicable to field, and sometimes inefficient. Studies show that polymer coatings with anticorrosion and antimicrobial properties have been widely accepted as a novel and effective approach to prevent biocorrosion. The main purpose of this review is to summarize up the progressive status of polymer coatings used for combating microbial corrosion. Polymers used to synthesize protective coatings are generally divided into three categories: (i traditional polymers incorporated with biocides, (ii antibacterial polymers containing quaternary ammonium compounds, and (iii conductive polymers. The strategies to synthesize polymer coatings resort mainly to grafting antibacterial polymers from the metal substrate surface using novel surface-functionalization approaches, such as free radical polymerization, chemically oxidative polymerization, and surface-initiated atom transfer radical polymerization, as opposed to the traditional approaches of dip coating or spin coating.

  12. Ion Implantation of Polymers

    DEFF Research Database (Denmark)

    Popok, Vladimir

    2012-01-01

    is put on the low-energy implantation of metal ions causing the nucleation and growth of nanoparticles in the shallow polymer layers. Electrical, optical and magnetic properties of metal/polymer composites are under the discussion and the approaches towards practical applications are overviewed....

  13. Conducting polymer hydrogels

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav

    2017-01-01

    Roč. 71, č. 2 (2017), s. 269-291 ISSN 0366-6352 R&D Projects: GA ČR(CZ) GA16-02787S Institutional support: RVO:61389013 Keywords : aerogel * conducting polymers * conductivity Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.258, year: 2016

  14. based gel polymer electrolytes

    Indian Academy of Sciences (India)

    operating systems. With this situation, attempts have been made in poly (ethylene oxide) (PEO) based polymer electrolytes to reach an appreciable electrical conducti- vity at ambient temperature (Wright 1975; Martuscelli et al 1984). Generally solid polymer electrolytes have many advantages, viz. high ionic conductivity, ...

  15. PEO polymer electrolytes

    Indian Academy of Sciences (India)

    Unknown

    vs temperature plots showed the enhancement of conductivity with TiO2 added nanocomposite ceramic fillers. The enhanced conductivity is ... developing mixed polymer electrolyte by using a novel class of plasticizers. Classical polymer ..... phology of the ceramic filler could optimize the conduc- tion. This might lead to the ...

  16. Doped Chiral Polymer Metamaterials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Doped Chiral Polymer Metamaterials (DCPM) with tunable resonance frequencies have been developed by adding plasmonic inclusions into chiral polymers with variable...

  17. Mechanical reinforcement and segmental dynamics of polymer nanocomposites

    Science.gov (United States)

    Gong, Shushan

    The addition of nanofiller into a polymer matrix will dramatically change the physical properties of polymer. The introduction of nanofiller makes the polymer more applicable in many industries, such as automobile tires, coatings, semiconductors, and packaging. The altered properties are not the simple combination of the characters from the two components. The interactions in polymer nanocomposites play an important role in determining the physical properties. This dissertation focuses on the mechanical properties of polymer nanocomposites (silica/poly-2-vinylpyridine) above their glass transition temperature Tg, as a model for automobile tires, which utilize small silica particles in crosslinked rubber far above Tg. We also investigate the impacts of the interaction between particle filler and polymer matrix on the altered mechanical properties. Dielectric relaxation spectroscopy (DRS) is used to study the glassy bound polymer layers formed around the particles. The results show evidence of the existence of immobilized polymer layers at the surface of each nanoparticle. At the same time, the thickness of the immobilized polymer layers is quantified and formed to be around 2 nm. Then we consider particles with glassy bound polymer layers are bridged together (either rubbery bridge or glassy bridge) by polymer chains and form small clusters. Clusters finally percolate to form a particle-polymer network as loading fraction increases. Rheology is used to study the network formation, and to predict the boundary of rubbery bridge and glassy bridge regimes. The distance between particles determines the type of polymer bridging. The particle spacing larger than Kuhn length makes flexible (rubbery) bridge with rheology described by a flexible Rouse model for percolation. When the spacing is shorter than the Kuhn length (~ 1nm), stiffer bridge forms instead, which is called glassy bridge. The mechanical differences between rubbery bridge and glassy bridge, and the effect of

  18. Polymer wear evaluation

    DEFF Research Database (Denmark)

    Lagerbon, Mikkel; Sivebæk, Ion Marius

    2012-01-01

    Polymer wear plays an increasing role in manufacturing of machine parts for e.g. medical devices. Some of these have an expected lifetime of five to eight years during which very little wear of the components is acceptable. Too much wear compromises the dosage accuracy of the device and thereby...... the safety of the patients. Prediction of the wear of polymers is complicated by the low thermal conductivity of this kind of material. It implies that any acceleration of testing conditions by increased contact pressure and/or sliding velocity will make the polymer fail due to exaggerated heat buildup....... This is not the kind of wear observed in medical devices. In the present work a method was developed capable of evaluating the wear progression in polymer-polymer contacts. The configuration of the setup is injection moulded specimens consisting of an upper part having a toroid shape and a lower flat part. The sliding...

  19. Temperature- and light-responsive smart polymer materials.

    Science.gov (United States)

    Jochum, Florian D; Theato, Patrick

    2013-09-07

    Stimuli-responsive polymers have been attracting great interest within the scientific community for several decades. The unique feature to respond to small changes in the environmental conditions has made this class of materials very promising for several applications in the field of nanoscience, nanotechnology and nanomedicine. So far, several different chemical, physical or biochemical stimuli have been investigated within natural or synthetic polymers. Very interesting and appealing seems to be the combination of several stimuli to tune the properties of these materials in manifold ways. Within this present review, we want to highlight the recent progress in the field of synthetic stimuli-responsive polymers combining temperature and light responsiveness.

  20. Photochemical Stability of π-Conjugated Polymers for Polymer Solar Cells: a Rule of Thumb

    DEFF Research Database (Denmark)

    Manceau, Matthieu

    2010-01-01

    A comparative photochemical stability study of a wide range of π-conjugated polymers relevant to polymer solar cells is presented. More than 20 samples were selected to cover a broad variety of polymer types (purely donor, donor / acceptor, thermo-cleavable) and chemical structures. Many...... of the moieties commonly used in the PSCs field are thus included in this study. The behavior of each material has been carefully investigated under simulated sunlight (1 sun, 1000 W m-2, AM 1.5G) and ambient atmosphere. Degradation was monitored all along ageing combining UV-visible and Infra-red spectroscopies....... Polymer durability was shown to cover a very broad range of values, from very few hours (e.g. MEH-PPV) to several thousands of hours (e.g. some thermo-cleaved samples). As all the experiments were conducted under the same conditions, comparison of the collected data was possible and the influence...

  1. Selective micro metallization of polymers for biomedical and medical application

    DEFF Research Database (Denmark)

    Islam, Mohammad Aminul; Hansen, Hans Nørgaard; Tang, Peter Torben

    Integration of micro/nano metallic structures in polymer devices is a broad multi-disciplinary research field, consisting of various combinations of mechanical, chemical and physical fabrication methods. Some of these combinations have been known for years and other combinations or methods are ve...

  2. Polymer-Polymer Miscibility and Enthalpy Relaxations

    NARCIS (Netherlands)

    Bosma, Martin; Brinke, Gerrit ten; Ellis, Thomas S.

    Annealing of polymers below the glass transition temperature results in a decrease in enthalpy that is recovered during heating. The enthalpy recovery is visible as an endothermic peak in a differential scanning calorimetry (DSC) scan. The position of this peak depends on the thermal treatment given

  3. Study of Hydrophobic and Ionizable Hydrophilic Copolymers at Polymer/Solid and Polymer/Liquid Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Perahia, Dvora

    2011-11-01

    Joint experimental-computational efforts were set to characterize the interfacial effects on the structure and dynamics of polymers consisting of highly rigid hydrophilic-ionizable and hydrophobic sub-units within one polymeric chain casted into thin films of several molecular dimensions. Focusing on the ultra thin film region we separate out the interfacial effects from bulk characteristics. Specifically, the study sought to: identify the parameters that control the formation of a stable polymer-solid interface. The study consists of two components, experimental investigations and computational efforts. The experimental component was designed to derive empirical trends that can be used to correlate the set of coupled polymer molecular parameters with the interfacial characteristics of these polymers, and their response to presence of solvents. The computational study was designed to provide molecular insight into the ensemble averages provided by the experimental efforts on multiple length scales from molecular dimensions, to the nanometer lengths to a macroscopic understanding of solvent interactions with structured polymers. With the ultimate goal of correlating molecular parameters to structure, dynamics and properties of ionic polymers, the first stage of the research began with the study of two systems, one which allowed tailoring the flexibility of the backbone without the presence of ionic groups, but with a potential to sulfonate groups at a later stage, and a polymer whose backbone is rigid and the density of the ionic group can be varied. The combined experimental and computational studies significantly extended the understanding of polymers at interfaces from model systems to polydispersed copolymers with blocks of varying nature and complexity. This new insight directly affects the design of polymers for sustainable energy applications from batteries and fuel cells to solar energy.

  4. Soluble porphyrin polymers

    Science.gov (United States)

    Gust, Jr., John Devens; Liddell, Paul Anthony

    2015-07-07

    Porphyrin polymers of Structure 1, where n is an integer (e.g., 1, 2, 3, 4, 5, or greater) ##STR00001## are synthesized by the method shown in FIGS. 2A and 2B. The porphyrin polymers of Structure 1 are soluble in organic solvents such as 2-MeTHF and the like, and can be synthesized in bulk (i.e., in processes other than electropolymerization). These porphyrin polymers have long excited state lifetimes, making the material suitable as an organic semiconductor for organic electronic devices including transistors and memories, as well as solar cells, sensors, light-emitting devices, and other opto-electronic devices.

  5. SANS studies of polymers

    International Nuclear Information System (INIS)

    Wignall, G.D.

    1984-10-01

    Before small-angle neutron scattering (SANS), chain conformation studies were limited to light and small angle x-ray scattering techniques, usually in dilute solution. SANS from blends of normal and labeled molecules could give direct information on chain conformation in bulk polymers. Water-soluble polymers may be examined in H 2 O/D 2 O mixtures using contrast variation methods to provide further information on polymer structure. This paper reviews some of the information provided by this technique using examples of experiments performed at the National Center for Small-Angle Scattering Research (NCSASR)

  6. Polymers in separation processes

    Science.gov (United States)

    Wieszczycka, Karolina; Staszak, Katarzyna

    2017-05-01

    Application of polymer materials as membranes and ion-exchange resins was presented with a focus on their use for the recovery of metal ions from aqueous solutions. Several membrane techniques were described including reverse osmosis, nanofiltration, ultrafiltration, diffusion and Donnan dialysis, electrodialysis and membrane extraction system (polymer inclusion and supported membranes). Moreover, the examples of using ion-exchange resins in metal recovery were presented. The possibility of modification of the resin was discussed, including hybrid system with metal cation or metal oxide immobilized on polymer matrices or solvent impregnated resin.

  7. Microstructured polymer optical fibres

    CERN Document Server

    Large, Maryanne; Barton, Geoff; van Eijkelenborg, Martijn A

    2008-01-01

    Microstructured Polymer Optical Fibres describes the optical properties of microstructured fibres, how they are made and modelled, and outlines some potential applications. These applications include areas where polymer fibres are already used, such as high-data rate transmission for Fibre-to-the Home or within cars, as well as completely new areas such as the photonic bandgap transmission of ""difficult"" wavelengths. Emphasising a conceptual understanding of the underlying physics, Microstructured Polymer Optical Fibres is clearly written, and includes numerous illustrations. It provides an

  8. Biomedical applications of polymers

    CERN Document Server

    Gebelein, C G

    1991-01-01

    The biomedical applications of polymers span an extremely wide spectrum of uses, including artificial organs, skin and soft tissue replacements, orthopaedic applications, dental applications, and controlled release of medications. No single, short review can possibly cover all these items in detail, and dozens of books andhundreds of reviews exist on biomedical polymers. Only a few relatively recent examples will be cited here;additional reviews are listed under most of the major topics in this book. We will consider each of the majorclassifications of biomedical polymers to some extent, inclu

  9. Polymer Composites Corrosive Degradation: A Computational Simulation

    Science.gov (United States)

    Chamis, Christos C.; Minnetyan, Levon

    2007-01-01

    A computational simulation of polymer composites corrosive durability is presented. The corrosive environment is assumed to manage the polymer composite degradation on a ply-by-ply basis. The degradation is correlated with a measured pH factor and is represented by voids, temperature and moisture which vary parabolically for voids and linearly for temperature and moisture through the laminate thickness. The simulation is performed by a computational composite mechanics computer code which includes micro, macro, combined stress failure and laminate theories. This accounts for starting the simulation from constitutive material properties and up to the laminate scale which exposes the laminate to the corrosive environment. Results obtained for one laminate indicate that the ply-by-ply degradation degrades the laminate to the last one or the last several plies. Results also demonstrate that the simulation is applicable to other polymer composite systems as well.

  10. The interplay of nanostructure and efficiency of polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yin Chunhong

    2008-12-04

    The aim of this thesis is to achieve a deep understanding of the working mechanism of polymer based solar cells and to improve the device performance. Two types of the polymer based solar cells are studied here: the polymer-polymer solar cells, and the polymer-small molecule solar cell which has polymer as electron donor incorporating with organic small molecule as electron acceptor. For the polymer-polymer devices, I compared the photocurrent characteristics of bilayer and blend devices as well as the blend devices with different nano-morphology, which is fine tuned by applying solvents with different boiling points. The main conclusion based on the complementary measurements is that the performance-limiting step is the field-dependent generation of free charge carriers, while bimolecular recombination and charge extraction do not compromise device performance. Regarding polymer-small molecular hybrid solar cells I combined the hole-transporting polymer M3EH-PPV with a novel small molecule electron acceptor vinazene. This molecule can be either deposited from solution or by thermal evaporation, allowing for a large variety of layer architectures to be realized. I then demonstrated that the layer architecture has a large influence on the photovoltaic properties. Solar cells with very high fill factors of up to 57 % and an open circuit voltage of 1V without thermal treatment of the devices were achieved. In the past, fill factors of solar cells exceeding 50 % have only been observed when using fullerene-derivatives as the electron-acceptor. The finding that proper processing of polymer-vinazene devices leads to similar high values is a major step towards the design of efficient polymer-based solar cells. (orig.)

  11. Recent Developments in Graphene/Polymer Nanocomposites for Application in Polymer Solar Cells

    Directory of Open Access Journals (Sweden)

    Ana Maria Díez-Pascual

    2018-02-01

    Full Text Available Graphene (G and its derivatives, graphene oxide (GO and reduced graphene oxide (rGO have enormous potential for energy applications owing to their 2D structure, large specific surface area, high electrical and thermal conductivity, optical transparency, and huge mechanical strength combined with inherent flexibility. The combination of G-based materials with polymers leads to new nanocomposites with enhanced structural and functional properties due to synergistic effects. This review briefly summarizes recent progress in the development of G/polymer nanocomposites for use in polymer solar cells (PSCs. These nanocomposites have been explored as transparent conducting electrodes (TCEs, active layers (ALs and interfacial layers (IFLs of PSCs. Photovoltaic parameters, such as the open-circuit voltage (Voc, short-circuit current density (Jsc, fill factor (FF and power-conversion efficiency (PCE are compared for different device structures. Finally, future perspectives are discussed.

  12. DESIGN AND EVALUATION OF LOSARTAN POTASSIUM MATRIX TABLETS WITH NATURAL AND SYNTHETIC POLYMERS

    OpenAIRE

    R. L. C. Sasidhar et al.

    2012-01-01

    The objective of the study was to formulate controlled release matrix tablets of losartan Potassium by using a combination of hydrophilic synthetic polymer like poly (ethylene oxides) and natural gums like xanthan gum, karaya gum and guar gum. A combination of synthetic hydrophobic polymers like methacrylates with synthetic hydrophilic polymer like poly (ethylene oxide) was also used in the preparation of matrix tablets and evaluated for their influence on controlled drug release. The matrix ...

  13. Physical theory of excitons in conducting polymers.

    Science.gov (United States)

    Brazovskii, Serguei; Kirova, Natasha

    2010-07-01

    In this tutorial review, we cover the solid state physics approach to electronic and optical properties of conducting polymers. We attempt to bring together languages and advantages of the solid state theory for polymers and of the quantum chemistry for monomers. We consider polymers as generic one-dimensional semiconductors with features of strongly correlated electronic systems. Our model combines the long range electron-hole Coulomb attraction with a specific effect of strong intra-monomer electronic correlations, which results in effective intra-monomer electron-hole repulsion. Our approach allows to go beyond the single-chain picture and to compare excitons for polymers in solutions and in films. The approach helps connecting such different questions as shallow singlet and deep triplet excitons, stronger binding of interchain excitons in films, crossings of excitons' branches, 1/N energies shifts in oligomers. We describe a strong suppression of the luminescence from free charge carriers by long-range Coulomb interactions. Main attention is devoted to the most requested in applications phenyl based polymers. The specifics of the benzene ring monomer give rise to existence of three possible types of excitons: Wannier-Mott, Frenkel and intermediate ones. We discuss experimental manifestations of various excitons and of their transformations. We touch effects of the time-resolved self-trapping by libron modes leading to formation of torsion polarons.

  14. Superabsorbent polymer; Kokyushusei porima

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, M. [Sanyo Kasei Kogyo K.K., Tokyo (Japan)

    1996-07-20

    Superabsorbent polymer (SAP) which has the absorbing ability from several hundreds to thousand times of the dead weight possesses many other functions in addition to the absorbing function, and studies on its application to various fields have been carried on very actively. Particularly, about 90% of the demand is for the application to body fluid absorber in the fields of sanitary materials. Basic water absorption mechanism, kinds, production methods, special features and applied cases of superabsorbent polymer are introduced. SAP is structured by loosely bridged water soluble polymer, particularly polymer electrolyte, to provide water unsoluble and water swelling properties. The kinds and production methods of SAP are described. SAP has respiration property in addition to the high water absorbing power and water holding ability. It has carboxyl ions, and has ammonia absorption ability and polyvalent metal ion adsorption ability. Paper diapers, water holding materials for soil, and cold reserving materials are discussed as examples of SAP application. 3 refs., 2 figs., 1 tab.

  15. Rheology of Supramolecular Polymers

    DEFF Research Database (Denmark)

    Shabbir, Aamir

    efficient processes or biomedical areas. Design and development of supramolecular polymers using ionic, hydrogen bonding or transition metal complexes with tailored properties requires deep understanding of dynamics both in linear and non-linear deformations. While linear rheology is important to understand...... the dynamics under equilibrium conditions, extensional rheology is relevant during the processing or in the usage of polymers utilizing supramolecular associations for example, acrylic based pressure sensitive adhesives are subjected to extensional deformations during the peeling where strain hardening......) hydrogen bonding polymers, and (b) ionic bonding polymers (hereafter termed as ionomers). We study linear and non-linear rheology fora model system of entangled pure poly(n-butyl acrylate), PnBA, homopolymer andfour poly(acrylic acid), PnBA-PAA, copolymers with varying AA side groups synthesizedvia...

  16. Conjugated Polymer Solar Cells

    National Research Council Canada - National Science Library

    Paraschuk, Dmitry Y

    2006-01-01

    This report results from a contract tasking Moscow State University as follows: Conjugated polymers are promising materials for many photonics applications, in particular, for photovoltaic and solar cell devices...

  17. Tunable Optical Polymer Systems

    National Research Council Canada - National Science Library

    Jenekhe, S. A; Bard, Allen J; Chen, S. H; Hammond, P. T; Rothberg, L. J

    2004-01-01

    This multidisciplinary university research initiative (MURI) program investigated tunable optical polymer systems suitable for large-area color-switchable coatings and devices, displays, sensors, and other electronic applications...

  18. Zwitterionic Electroactive Polymer Actuators

    National Research Council Canada - National Science Library

    Zakin, Mitchell

    2002-01-01

    .... The enabling technology is a zwitterionic polyaniline derivative in which generation of +/- charge pairs upon oxidation provides significant conformational distortion along the polymer backbone, and a concomitant change in free volume...

  19. Biocatalytic Polymer Skin Adhesives

    National Research Council Canada - National Science Library

    LeJeune, Keith

    2001-01-01

    .... Preliminary results also suggest that the incorporation of enzymes within such polymers reduces immunogenic and allergenic responses that are often observed when applying protein-based materials on skin tissue...

  20. Polymers for Protein Conjugation

    Directory of Open Access Journals (Sweden)

    Gianfranco Pasut

    2014-01-01

    Full Text Available Polyethylene glycol (PEG at the moment is considered the leading polymer for protein conjugation in view of its unique properties, as well as to its low toxicity in humans, qualities which have been confirmed by its extensive use in clinical practice. Other polymers that are safe, biodegradable and custom-designed have, nevertheless, also been investigated as potential candidates for protein conjugation. This review will focus on natural polymers and synthetic linear polymers that have been used for protein delivery and the results associated with their use. Genetic fusion approaches for the preparation of protein-polypeptide conjugates will be also reviewed and compared with the best known chemical conjugation ones.

  1. Edible Polymers: Challenges and Opportunities

    OpenAIRE

    Subhas C. Shit; Pathik M. Shah

    2014-01-01

    Edible polymers have established substantial deliberation in modern eons because of their benefits comprising use as edible materials over synthetic polymers. This could contribute to the reduction of environmental contamination. Edible polymers can practically diminish the complexity and thus improve the recyclability of materials, compared to the more traditional non-environmentally friendly materials and may be able to substitute such synthetic polymers. A synthetic hydrogel polymer unlock...

  2. Reactive polymer fused deposition manufacturing

    Science.gov (United States)

    Kunc, Vlastimil; Rios, Orlando; Love, Lonnie J.; Duty, Chad E.; Johs, Alexander

    2017-05-16

    Methods and compositions for additive manufacturing that include reactive or thermosetting polymers, such as urethanes and epoxies. The polymers are melted, partially cross-linked prior to the depositing, deposited to form a component object, solidified, and fully cross-linked. These polymers form networks of chemical bonds that span the deposited layers. Application of a directional electromagnetic field can be applied to aromatic polymers after deposition to align the polymers for improved bonding between the deposited layers.

  3. Semi-metallic polymers

    DEFF Research Database (Denmark)

    Bubnova, Olga; Khan, Zia Ullah; Wang, Hui

    2014-01-01

    Polymers are lightweight, flexible, solution-processable materials that are promising for low-cost printed electronics as well as for mass-produced and large-area applications. Previous studies demonstrated that they can possess insulating, semiconducting or metallic properties; here we report...... a Fermi glass to a semi-metal. The high Seebeck value, the metallic conductivity at room temperature and the absence of unpaired electron spins makes polymer semi-metals attractive for thermoelectrics and spintronics....

  4. Graphene-polymer composites

    Science.gov (United States)

    Carotenuto, G.; Romeo, V.; Cannavaro, I.; Roncato, D.; Martorana, B.; Gosso, M.

    2012-09-01

    Graphene is a novel nanostructured material that can be conveniently used as filler for thermoplastic polymers or thermosetting resins, and the resulting nanocomposite material has unique mechanical and chemical/physical properties. Industrial production of graphene/polymer materials requires the availability of a chemical route to produce massive amount of graphene. Natural graphite flakes can be the best starting material for a bulk-production of graphene to be used in the polymeric nanocomposite preparation.

  5. Sulfur polymer cement concrete

    International Nuclear Information System (INIS)

    Weber, H.H.; McBee, W.C.

    1990-01-01

    Sulfur-based composite materials formulated using sulfur polymer cement (SPC) and mineral aggregates are described and compared with conventional portland cement based materials. Materials characteristics presented include mechanical strength, chemical resistance, impact resistance, moisture permeation, and linear shrinkage during placement and curing. Examples of preparation and placement of sulfur polymer cement concrete (SC) are described using commercial scale equipment. SC applications presented are focused into hostile chemical environments where severe portland cement concrete (PCC) failure has occurred

  6. Interfaced conducting polymers

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Bober, Patrycja; Trchová, Miroslava; Nuzhnyy, Dmitry; Bovtun, Viktor; Savinov, Maxim; Petzelt, Jan; Prokeš, J.

    2017-01-01

    Roč. 224, February (2017), s. 109-115 ISSN 0379-6779 R&D Projects: GA ČR(CZ) GA16-02787S Institutional support: RVO:61389013 ; RVO:68378271 Keywords : polyaniline * polypyrrole * poly(p-phenylenediamine) Subject RIV: CD - Macromolecular Chemistry; CD - Macromolecular Chemistry (FZU-D) OBOR OECD: Polymer science; Polymer science (FZU-D) Impact factor: 2.435, year: 2016

  7. Rapid Polymer Sequencer

    Science.gov (United States)

    Stolc, Viktor (Inventor); Brock, Matthew W (Inventor)

    2013-01-01

    Method and system for rapid and accurate determination of each of a sequence of unknown polymer components, such as nucleic acid components. A self-assembling monolayer of a selected substance is optionally provided on an interior surface of a pipette tip, and the interior surface is immersed in a selected liquid. A selected electrical field is impressed in a longitudinal direction, or in a transverse direction, in the tip region, a polymer sequence is passed through the tip region, and a change in an electrical current signal is measured as each polymer component passes through the tip region. Each of the measured changes in electrical current signals is compared with a database of reference electrical change signals, with each reference signal corresponding to an identified polymer component, to identify the unknown polymer component with a reference polymer component. The nanopore preferably has a pore inner diameter of no more than about 40 nm and is prepared by heating and pulling a very small section of a glass tubing.

  8. Crystallization in polymer nanocomposites

    Science.gov (United States)

    Chrissopoulou, Kyriakh; Perivolari, Helena; Leisch, Stefanos; Papananou, Hellen; Anastasiadis, Spiros H.

    Polymer crystallization is a very interesting topic since it is responsible for the final properties of the materials. On the other hand, addition of inorganic nanomaterials has been recently widely used to optimize polymer properties. In this work, the effect of the presence of surfaces and of the severe confinement on polymer morphology and crystallization are investigated in hydrophilic nanohybrids of poly(ethylene oxide) and silica nanoparticles of different sizes; hybrids with different ratios of the two kinds of nanoparticles were synthesized as well, to achieve the highest confinement. Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD) were utilized to investigate the behavior and showed that the polymer chains that were able to crystallize showed a different crystalline behavior in the hybrids with lower Tm and lower crystallinity. Under severe confinement polymer crystallization was completely suppressed. Moreover, the crystallization kinetics was investigated with Isothermal Polarized Optical Microscopy (POM) and Isothermal Differential Scanning Calorimetry (DSC) showing different characteristics in the hybrids compared to that of the neat polymer depending on the silica content. Sponsored by the Greek GSRT (AENAO research project, Action KRIPIS)

  9. Polymer filtration: A new technology for selective metals recovery

    Energy Technology Data Exchange (ETDEWEB)

    Smith, B.F.; Robison, T.W.; Cournoyer, M.E.; Wilson, K.V.; Sauer, N.N.; Mullen, K.I.; Lu, M.T.; Jarvinen, J.J.

    1995-04-01

    Polymer Filtration (PF) was evaluated for the recovery of electroplating metal ions (zinc and nickel) from rinse waters. Polymer Filtration combines the use of water-soluble metal-binding polymers and ultrafiltration to concentrate metal ions from dilute rinse water solutions. The metal ions are retained by the polymers; the smaller, unbound species freely pass through the ultrafiltration membrane. By using this process the ultrafiltered permeate more than meets EPA discharge limits. The metal ions are recovered from the concentrated polymer solution by pH adjustment using diafiltration and can be recycled to the original electroplating baths with no deleterious effects on the test panels. Metal-ion recovery is accomplished without producing sludge.

  10. Self-Sensing Ionic Polymer Actuators: A Review

    Directory of Open Access Journals (Sweden)

    Karl Kruusamäe

    2015-03-01

    Full Text Available Ionic electromechanically active polymers (IEAP are laminar composites that can be considered attractive candidates for soft actuators. Their outstanding properties such as low operating voltage, easy miniaturization, and noiseless operation are, however, marred by issues related to the repeatability in the production and operation of these materials. Implementing closed-loop control for IEAP actuators is a viable option for overcoming these issues. Since IEAP laminates also behave as mechanoelectrical sensors, it is advantageous to combine the actuating and sensing functionalities of a single device to create a so-called self-sensing actuator. This review article systematizes the state of the art in producing self-sensing ionic polymer actuators. The IEAPs discussed in this paper are conducting (or conjugated polymers actuators (CPA, ionic polymer-metal composite (IPMC, and carbonaceous polymer laminates.

  11. 40 CFR 723.250 - Polymers.

    Science.gov (United States)

    2010-07-01

    ..., boron, phosphorus, titanium, manganese, iron, nickel, copper, zinc, tin, and zirconium. (3) Polymers... introduce into the polymer elements, properties, or functional groups that would render the polymer...

  12. Simulations of Polymer Translocation

    Science.gov (United States)

    Vocks, H.

    2008-07-01

    Transport of molecules across membranes is an essential mechanism for life processes. These molecules are often long, and the pores in the membranes are too narrow for the molecules to pass through as a single unit. In such circumstances, the molecules have to squeeze -- i.e., translocate -- themselves through the pores. DNA, RNA and proteins are such naturally occuring long molecules in a variety of biological processes. Understandably, the process of translocation has been an active topic of current research: not only because it is a cornerstone of many biological processes, but also due to its relevance for practical applications. Translocation is a complicated process in living organisms -- the presence of chaperone molecules, pH, chemical potential gradients, and assisting molecular motors strongly influence its dynamics. Consequently, the translocation process has been empirically studied in great variety in biological literature. Study of translocation as a biophysical process is more recent. Herein, the polymer is simplified to a sequentially connected string of N monomers as it passes through a narrow pore on a membrane. The quantities of interest are the typical time scale for the polymer to leave a confining cell (the ``escape of a polymer from a vesicle'' time scale), and the typical time scale the polymer spends in the pore (the ``dwell'' time scale) as a function of N and other parameters like membrane thickness, membrane adsorption, electrochemical potential gradient, etc. Our research is focused on computer simulations of translocation. Since our main interest is in the scaling properties, we use a highly simplified description of the translocation process. The polymer is described as a self-avoiding walk on a lattice, and its dynamics consists of single-monomer jumps from one lattice site to another neighboring one. Since we have a very efficient program to simulate such polymer dynamics, which we decribe in Chapter 2, we can perform long

  13. Preparation of a Thermally Light-Transmittance-Controllable Film from a Coexistent System of Polymer-Dispersed and Polymer-Stabilized Liquid Crystals.

    Science.gov (United States)

    Guo, Shu-Meng; Liang, Xiao; Zhang, Cui-Hong; Chen, Mei; Shen, Chen; Zhang, Lan-Ying; Yuan, Xiao; He, Bao-Feng; Yang, Huai

    2017-01-25

    Polymer-dispersed liquid crystal (PDLC) and polymer-stabilized liquid crystal (PSLC) systems are the two primary distinct systems in the field of liquid crystal (LC) technology, and they are differentiated by their unique microstructures. Here, we present a novel coexistent system of polymer-dispersed and polymer-stabilized liquid crystals (PD&SLCs), which forms a homeotropically aligned polymer network (HAPN) within the LC droplets after a microphase separation between the LC and polymer matrix and combines the advantages of both the PDLC and PSLC systems. Then, we prepare a novel thermally light-transmittance-controllable (TLTC) film from the PD&SLC system, where the transmittance can be reversibly changed through thermal control from a transparent to a light-scattering state. The film also combines the advantageous features of flexibility and a potential for large-scale manufacturing, and it shows significant promise in future applications from smart windows to temperature sensors.

  14. Confined relaxations of grafted polymer in solutions of linear polymer

    Science.gov (United States)

    Poling-Skutvik, Ryan; Krishnamoorti, Ramanan; Conrad, Jacinta

    Using neutron spin echo spectroscopy (NSE), we investigate the relaxations of polymer grafted to silica nanoparticles dispersed in semidilute solutions of linear polymer. The grafted polymer has a radius of gyration comparable to radius of the silica nanoparticle with a moderate grafting density so that the grafted polymer is more extended than a Gaussian chain. On length scales ranging from 1 to 20 nm and time scales less than 100 ns, the dynamics of the grafted polymer deviate from the standard Zimm model derived for linear polymers. Instead, the polymer chains are confined and unable to fully relax over the experimental time. The confinement length agrees with the distance between chains decreases as the linear polymer concentration is increased. Additionally, the confinement length is independent of linear polymer molecular weight, suggesting that linear polymer cannot penetrate the grafted layer. Instead, the grafted chains collapse onto themselves, similar to the structural changes observed in systems of star and linear polymers at high concentrations of linear polymer. We verify this physical picture using small-angle x-ray scattering and atomic force microscopy to observe aggregation of grafted particles at high concentrations of linear polymer.

  15. Imprinted Polymers in Wastewater Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Eastman, Christopher; Goodrich, Scott; Gartner, Isabelle; Mueller, Anja

    2004-03-31

    In wastewater treatment, a method that specifically recognizes a variety of impurities in a flexible manner would be useful for treatment facilities with varying needs. Current purification techniques (i.e. bacteria, oxidation, reduction, precipitation and filtration) are nonspecific and difficult to control in complex mixtures. Heavy metal removal is particularly important in improving the efficiency of wastewater treatment, as they inhibit or even destroy the bacteria used for filtration. Imprinting polymerization is a technique that allows for the efficient removal of specific compounds and has been used in purification of enantiomers. It has potential to be applied in wastewater systems with the impurities acting as the template for the imprinting polymerization. The polymer with the bound impurities intact can then be removed via precipitation. After removal of the impurity the polymer can be reused. Data for the imprinting polymerization of polyacrylates and polyacrylamides for several metal complexes will be presented. Imprinting polymerization in combination with emulsion polymerization to improve the removal of hydrophobic contaminants will be described. Removal efficiencies will be presented and compared with conventional wastewater treatment methods.

  16. Processing and characterization of ceramic superconductor/polymer composites

    International Nuclear Information System (INIS)

    Kander, R.G.; Namboodri, S.L.

    1993-01-01

    One way to more easily process a brittle high-temperature ceramic superconductor into a useful structure is to combine it with a polymer to form a composite material. Processing of polymer-based composites into complex shapes is well established and relatively easy when compared with traditional ceramic processing unit operations. In addition, incorporating a ceramic superconductor into a polymer matrix can improve mechanical performance as compared with a monolithic ceramic. Finally, because ceramic superconductors are susceptible to attack by moisture, a polymer-based composite structure can also provide protection from deleterious environmental effects. This paper focuses on the processing and subsequent characterization of ceramic superconductor/polymer composites designed primarily for electromagnetic shielding and diamagnetic applications. YBa 2 Cu 3 O 7-x [YBCO] ceramic superconductor is combined with poly(methyl methacrylate) [PMMA] to form novel composite structures. Composite structures have been molded with both a discontinuous superconducting phase (i.e., ceramic particulate reinforced polymers) and with a continuous superconducting phase (i.e., polymer infiltrated porous ceramics). Characterization of these composite structures includes the determination of diamagnetic strength, electromagnetic shielding effectiveness, mechanical performance, and environmental resistance. The goal of this program is to produce a composite structure with increased mechanical integrity and environmental resistance at liquid nitrogen temperatures without compromising the electromagnetic shielding and diamagnetic properties of the superconducting phase. Composites structures of this type are potentially useful in numerous magnetic applications including electromagnetic shielding, magnetic sensors, energy storage, magnetic levitation, and motor windings

  17. Review of Polymer, Dye-Sensitized, and Hybrid Solar Cells

    Directory of Open Access Journals (Sweden)

    S. N. F. Mohd-Nasir

    2014-01-01

    Full Text Available The combination of inorganic nanoparticles semiconductor, conjugated polymer, and dye-sensitized in a layer of solar cell is now recognized as potential application in developing flexible, large area, and low cost photovoltaic devices. Several conjugated low bandgap polymers, dyes, and underlayer materials based on the previous studies are quoted in this paper, which can provide guidelines in designing low cost photovoltaic solar cells. All of these materials are designed to help harvest more sunlight in a wider range of the solar spectrum besides enhancing the rate of charge transfer in a device structure. This review focuses on developing solid-state dye-synthesized, polymer, and hybrid solar cells.

  18. Piezoresistance in Polymer Nanocomposites

    Science.gov (United States)

    Rizvi, Reza

    Piezoresistivity in conductive polymer nanocomposites occurs because of the disturbance of particle networks in the polymer matrix. The piezoresistance effect becomes more prominent if the matrix material is compliant making these materials attractive for applications that require flexible force and displacement sensors such as e-textiles and biomechanical measurement devices. However, the exact mechanisms of piezoresistivity including the relationship between the matrix polymer, conductive particle, internal structure and the composite's piezoresistance need to be better understood before it can be applied for such applications. The objective of this thesis is to report on the development of conductive polymer nanocomposites for use as flexible sensors and electrodes. Electrically conductive and piezoresistive nanocomposites were fabricated by a scalable melt compounding process. Particular attention was given to elucidating the role of matrix and filler materials, plastic deformation and porosity on the electrical conduction and piezoresistance. These effects were parametrically investigated through characterizing the morphology, electrical properties, rheological properties, and piezoresistivity of the polymer nanocomposites. The electrical and rheological behavior of the nanocomposites was modeled by the percolation-power law. Furthermore, a model was developed to describe the piezoresistance behavior during plastic deformation in relation to the stress and filler concentration.

  19. Efficient Xerographic Photoreceptors from Conjugated Polymers and Polymer Blends

    National Research Council Canada - National Science Library

    Zhang, Xuejun, Ph.D

    1998-01-01

    Bilayer xerographic photoreceptors in which pi-conjugated polymers and binary conjugated polymer blends are used as the charge generation layer have been fabricated, evaluated, and shown to be highly efficient...

  20. Polymer blend microspheres for controlled drug release: the techniques for preparation and characterization: a review article.

    Science.gov (United States)

    Dasan, K Priya; Rekha, C

    2012-11-01

    The use of polymers and their microspheres in drug delivery is well known for they are being widely used in the field of drug delivery. The polymer entraps a drug which is to be released in a predesigned manner in the body through biodegradation. The blending of polymers is one way of modifying and enhancing the properties of polymer- based products which is also a cost effective procedure rather than developing a new product. The molecular weight of the polymer, the composition of the blend, the sphere porosity and size, and drug distribution are found to be controllable factors on which drug delivery depends. Polymer blends are obtained by allowing two polymers to combine as one material which has the advantage of two or more polymers. Polymer microspheres are small spherical particles with diameters in the micrometer range between 1μm to 1000μm which are manufactured from various natural and synthetic materials. Microspheres are used to administer medication in a rate- controlled manner and sometimes in a targeted manner. This review presents various polymer blend- combinations in different ratios, the different processing techniques adopted and the details of their characterization through examples found in a literature survey. The characterization of the different polymer blends or microspheres showed changes in structure, increase in drug loading, encapsulation efficiency, biocompatibility and low cytotoxicity.

  1. SOLID STATE BATTERIES WITH CONDUCTING POLYMERS

    OpenAIRE

    Bénière , F.; Boils , D.; Cánepa , H.; Franco , J.; Le Corre , A.; Louboutin , J.

    1983-01-01

    The conducting polymers like (CH)x are very interesting materials for electrodes in electrochemical cells. We have combined such electrodes with solid electrolytes to build "all solid-state" batteries. The first prototypes using a silver anode and a silver conducting electrolyte have been working satisfactorily since two years. The performances have been tested with many batteries to study the electrical properties as well as the thermodynamical parameters. A number of cycles of charge-discha...

  2. Fingerprinting molecular relaxation in deformed polymers

    OpenAIRE

    Wang, Zhe; Lam, Christopher N.; Chen, Wei-Ren; Wang, Weiyu; Liu, Jianning; Liu, Yun; Porcar, Lionel; Stanley, Christopher B.; Zhao, Zhichen; Hong, Kunlun; Wang, Yangyang

    2017-01-01

    International audience; The flow and deformation of macromolecules is ubiquitous in nature and industry, and an understanding of this phenomenon at both macroscopic and microscopic length scales is of fundamental and practical importance. Here, we present the formulation of a general mathematical framework, which could be used to extract, from scattering experiments, the molecular relaxation of deformed polymers. By combining and modestly extending several key conceptual ingredients in the li...

  3. Phase Behavior in Asymmetric Polymer Blends

    OpenAIRE

    Nedoma, Alisyn Jenise

    2010-01-01

    Polymer composites combine the physical properties of two or more distinct chemical species into a single material. Blends of two homopolymers, mixed homogeneously or structured on the nanoscale, are particularly useful nanocomposite materials because ordering occurs via thermodynamic equilibration rather than costly nanofabrication. However, the majority of homopolymer pairs are immiscible, leading to mechanically unstable materials. This work explores one route for compatibilizing two im...

  4. Doped Chiral Polymer Metamaterials

    Science.gov (United States)

    Park, Cheol (Inventor); Kang, Jin Ho (Inventor); Gordon, Keith L. (Inventor); Sauti, Godfrey (Inventor); Lowther, Sharon E. (Inventor); Bryant, Robert G. (Inventor)

    2017-01-01

    Some implementations provide a composite material that includes a first material and a second material. In some implementations, the composite material is a metamaterial. The first material includes a chiral polymer (e.g., crystalline chiral helical polymer, poly-.gamma.-benzyl-L-glutamate (PBLG), poly-L-lactic acid (PLA), polypeptide, and/or polyacetylene). The second material is within the chiral polymer. The first material and the second material are configured to provide an effective index of refraction value for the composite material of 1 or less. In some implementations, the effective index of refraction value for the composite material is negative. In some implementations, the effective index of refraction value for the composite material of 1 or less is at least in a wavelength of one of at least a visible spectrum, an infrared spectrum, a microwave spectrum, and/or an ultraviolet spectrum.

  5. Active Polymer Gel Actuators

    Directory of Open Access Journals (Sweden)

    Shuji Hashimoto

    2010-01-01

    Full Text Available Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of heart muscles. Here we show a novel biomimetic gel actuator that can walk spontaneously with a wormlike motion without switching of external stimuli. The self-oscillating motion is produced by dissipating chemical energy of oscillating reaction. Although the gel is completely composed of synthetic polymer, it shows autonomous motion as if it were alive.

  6. Flame spraying of polymers

    International Nuclear Information System (INIS)

    Varacalle, D.J. Jr.; Zeek, D.P.; Couch, K.W.; Benson, D.M.; Kirk, S.M.

    1997-01-01

    Statistical design-of-experiment studies of the thermal spraying of polymer powders are presented. Studies of the subsonic combustion (i.e., Flame) process were conducted in order to determine the quality and economics of polyester and urethane coatings. Thermally sprayed polymer coatings are of interest to several industries for anticorrosion applications, including the chemical, automotive, and aircraft industries. In this study, the coating design has been optimized for a site-specific application using Taguchi-type fractional-factorial experiments. Optimized coating designs are presented for the two powder systems. A substantial range of thermal processing conditions and their effect on the resultant polymer coatings is presented. The coatings were characterized by optical metallography, hardness testing, tensile testing, and compositional analysis. Characterization of the coatings yielded the thickness, bond strength, Knoop microhardness, roughness, deposition efficiency, and porosity. Confirmation testing was accomplished to verify the coating designs

  7. Nanostructured silicate polymer concrete

    Directory of Open Access Journals (Sweden)

    Figovskiy Oleg L'vovich

    2014-03-01

    Full Text Available It has been known that acid-resistant concretes on the liquid glass basis have high porosity (up to 18~20 %, low strength and insufficient water resistance. Significant increasing of silicate matrix strength and density was carried out by incorporation of special liquid organic alkali-soluble silicate additives, which block superficial pores and reduce concrete shrinkage deformation. It was demonstrated that introduction of tetrafurfuryloxisilane additive sharply increases strength, durability and shock resistance of silicate polymer concrete in aggressive media. The experiments showed, that the strength and density of silicate polymer concrete increase in case of decreasing liquid glass content. The authors obtained optimal content of silicate polymer concrete, which possesses increased strength, durability, density and crack-resistance. Diffusive permeability of concrete and its chemical resistance has been investigated in various corroding media.

  8. Conductivity behaviour of polymer gel electrolytes: Role of polymer

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Polymer is an important constituent of polymer gel electrolytes along with salt and solvent. The salt provides ions for conduction and the solvent helps in the dissolution of the salt and also provides the medium for ion conduction. Although the polymer added provides mechanical stability to the electrolytes yet.

  9. Quantitative structure-activity relationships for green algae growth inhibition by polymer particles.

    Science.gov (United States)

    Nolte, Tom M; Peijnenburg, Willie J G M; Hendriks, A Jan; van de Meent, Dik

    2017-07-01

    After use and disposal of chemical products, many types of polymer particles end up in the aquatic environment with potential toxic effects to primary producers like green algae. In this study, we have developed Quantitative Structure-Activity Relationships (QSARs) for a set of highly structural diverse polymers which are capable to estimate green algae growth inhibition (EC50). The model (N = 43, R 2  = 0.73, RMSE = 0.28) is a regression-based decision tree using one structural descriptor for each of three polymer classes separated based on charge. The QSAR is applicable to linear homo polymers as well as copolymers and does not require information on the size of the polymer particle or underlying core material. Highly branched polymers, non-nitrogen cationic polymers and polymeric surfactants are not included in the model and thus cannot be evaluated. The model works best for cationic and non-ionic polymers for which cellular adsorption, disruption of the cell wall and photosynthesis inhibition were the mechanisms of action. For anionic polymers, specific properties of the polymer and test characteristics need to be known for detailed assessment. The data and QSAR results for anionic polymers, when combined with molecular dynamics simulations indicated that nutrient depletion is likely the dominant mode of toxicity. Nutrient depletion in turn, is determined by the non-linear interplay between polymer charge density and backbone flexibility. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Coil–globule transition of a polymer involved in excluded-volume interactions with macromolecules

    International Nuclear Information System (INIS)

    Odagiri, Kenta; Seki, Kazuhiko

    2015-01-01

    Polymers adopt extended coil and compact globule states according to the balance between entropy and interaction energies. The transition of a polymer between an extended coil state and compact globule state can be induced by changing thermodynamic force such as temperature to alter the energy/entropy balance. Previously, this transition was theoretically studied by taking into account the excluded-volume interaction between monomers of a polymer chain using the partition function. For binary mixtures of a long polymer and short polymers, the coil-globule transition can be induced by changing the concentration of the shorter polymers. Here, we investigate the transition caused by short polymers by generalizing the partition function of the long polymer to include the excluded-volume effect of short polymers. The coil-globule transition is studied as a function of the concentration of mixed polymers by systematically varying Flory’s χ-parameters. We show that the transition is caused by the interplay between the excluded-volume interaction and the dispersion state of short polymers in the solvent. We also reveal that the same results can be obtained by combining the mixing entropy and elastic energy if the volume of a long polymer is properly defined

  11. Polymers at cryogenic temperatures

    CERN Document Server

    Fu, Shao-Yun

    2013-01-01

    Kalia and Fu's novel monograph covers cryogenic treatment, properties and applications of cryo-treated polymer materials. Written by numerous international experts, the twelve chapters in this book offer the reader a comprehensive picture of the latest findings and developments, as well as an outlook on the field. Cryogenic technology has seen remarkable progress in the past few years and especially cryogenic properties of polymers are attracting attention through new breakthroughs in space, superconducting, magnetic and electronic techniques. This book is a valuable resource for researchers, educators, engineers and graduate students in the field and at technical institutions.

  12. Mechanically Invisible Polymer Coatings

    DEFF Research Database (Denmark)

    2014-01-01

    phase comprises particles, said particles comprising a filler material and an encapsulating coating of a second polymeric material, wherein the backbones of the first and second polymeric materials are the same. The composition may be used in electroactive polymers (EAPs) in order to obtain mechanically......The present invention relates to a composition comprising encapsulated particles in a polymeric material. The composition comprises a continuous phase and a discontinuous phase incorporated therein, wherein the continuous phase comprises a first polymeric material and wherein the discontinuous...... invisible polymer coatings....

  13. 'Stuffed' conducting polymers

    DEFF Research Database (Denmark)

    Winther-Jensen, Bjørn; Chen, Jun; West, Keld

    2005-01-01

    Conducting polymers (CP) obtained by oxidative polymerization using iron(III) salts shrink when Fe(II) and the excess counter ions are washed out after polymerization. This phenomenon can be used to incorporate active molecules into the CP matrix via their addition to the wash liquid. In the pres....... In the present work we demonstrate this principle on three different CP's: polypyrrole (PPy), poly-terthiophene (PTTh) and poly(3,4-ethylenedioxy thiophene) (PEDT), using ferrocene as a model molecule to be trapped in the polymer films. (c) 2005 Elsevier Ltd. All rights reserved....

  14. Nanoparticles from Renewable Polymers

    Directory of Open Access Journals (Sweden)

    Frederik Roman Wurm

    2014-07-01

    Full Text Available The use of polymers from natural resources can bring many benefits for novel polymeric nanoparticle systems. Such polymers have a variety of beneficial properties such as biodegradability and biocompatibility, they are readily available on large scale and at low cost. As the amount of fossil fuels decrease, their application becomes more interesting even if characterization is in many cases more challenging due to structural complexity, either by broad distribution of their molecular weights polysaccharides, polyesters, lignin or by complex structure (proteins, lignin. This review summarizes different sources and methods for the preparation of biopolymer-based nanoparticle systems for various applications.

  15. Antibacterial polymer coatings.

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Mollye C.; Allen, Ashley N.; Barnhart, Meghan; Tucker, Mark David; Hibbs, Michael R.

    2009-09-01

    A series of poly(sulfone)s with quaternary ammonium groups and another series with aldehyde groups are synthesized and tested for biocidal activity against vegetative bacteria and spores, respectively. The polymers are sprayed onto substrates as coatings which are then exposed to aqueous suspensions of organisms. The coatings are inherently biocidal and do not release any agents into the environment. The coatings adhere well to both glass and CARC-coated coupons and they exhibit significant biotoxicity. The most effective quaternary ammonium polymers kills 99.9% of both gram negative and gram positive bacteria and the best aldehyde coating kills 81% of the spores on its surface.

  16. Polymer Chemistry in High School.

    Science.gov (United States)

    Stucki, Roger

    1984-01-01

    Discusses why polymer chemistry should be added to the general chemistry curriculum and what topics are appropriate (listing traditional with related polymer topics). Also discusses when and how these topics should be taught. (JN)

  17. Edible Polymers: Challenges and Opportunities

    Directory of Open Access Journals (Sweden)

    Subhas C. Shit

    2014-01-01

    Full Text Available Edible polymers have established substantial deliberation in modern eons because of their benefits comprising use as edible materials over synthetic polymers. This could contribute to the reduction of environmental contamination. Edible polymers can practically diminish the complexity and thus improve the recyclability of materials, compared to the more traditional non-environmentally friendly materials and may be able to substitute such synthetic polymers. A synthetic hydrogel polymer unlocked a new possibility for development of films, coatings, extrudable pellets, and synthetic nanopolymers, particularly designed for medical, agricultural, and industrial fields. Edible polymers offer many advantages for delivering drugs and tissue engineering. Edible polymer technology helps food industries to make their products more attractive and safe to use. Novel edible materials have been derived from many natural sources that have conventionally been regarded as discarded materials. The objective of this review is to provide a comprehensive introduction to edible polymers by providing descriptions in terms of their origin, properties, and potential uses.

  18. Polymer architecture and drug delivery.

    Science.gov (United States)

    Qiu, Li Yan; Bae, You Han

    2006-01-01

    Polymers occupy a major portion of materials used for controlled release formulations and drug-targeting systems because this class of materials presents seemingly endless diversity in topology and chemistry. This is a crucial advantage over other classes of materials to meet the ever-increasing requirements of new designs of drug delivery formulations. The polymer architecture (topology) describes the shape of a single polymer molecule. Every natural, seminatural, and synthetic polymer falls into one of categorized architectures: linear, graft, branched, cross-linked, block, star-shaped, and dendron/dendrimer topology. Although this topic spans a truly broad area in polymer science, this review introduces polymer architectures along with brief synthetic approaches for pharmaceutical scientists who are not familiar with polymer science, summarizes the characteristic properties of each architecture useful for drug delivery applications, and covers recent advances in drug delivery relevant to polymer architecture.

  19. Shape memory polymer medical device

    Science.gov (United States)

    Maitland, Duncan [Pleasant Hill, CA; Benett, William J [Livermore, CA; Bearinger, Jane P [Livermore, CA; Wilson, Thomas S [San Leandro, CA; Small, IV, Ward; Schumann, Daniel L [Concord, CA; Jensen, Wayne A [Livermore, CA; Ortega, Jason M [Pacifica, CA; Marion, III, John E.; Loge, Jeffrey M [Stockton, CA

    2010-06-29

    A system for removing matter from a conduit. The system includes the steps of passing a transport vehicle and a shape memory polymer material through the conduit, transmitting energy to the shape memory polymer material for moving the shape memory polymer material from a first shape to a second and different shape, and withdrawing the transport vehicle and the shape memory polymer material through the conduit carrying the matter.

  20. Polymers in our daily life

    Directory of Open Access Journals (Sweden)

    Hassan Namazi

    2017-06-01

    Full Text Available Polymers are widely used advanced materials, which are found almost in every material used in our daily life. To date, the importance of polymers has been much more highlighted because of their applications in different dominions of sciences, technologies and industry – from basic uses to biopolymers and therapeutic polymers. The main aim of this editorial is to accentuate the pragmatic impacts of polymers in human daily life.

  1. Statistical properties of curved polymer

    Indian Academy of Sciences (India)

    For semiflexible polymers, the relevant non-dimensional quantity is lp/L, where lp is the persistence length (which is proportional to the bending modulus k) and L is the contour length of the polymer. In the limit, lp/L ≪ 1, the polymer behaves as a flexible polymer whereas in the limit lp/L ≥ 1 it behaves like a straight rod. For.

  2. Nonlinear microstructured polymer optical fibres

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch

    is potentially the case for microstructured polymer optical fibres (mPOFs). Another advantage is that polymer materials have a higher biocompatibility than silica, meaning that it is easier to bond certain types of biosensor materials to a polymer surface than to silica. As with silica PCFs, it is difficult...

  3. Viscoelastic Properties of Polymer Blends

    Science.gov (United States)

    Hong, S. D.; Moacanin, J.; Soong, D.

    1982-01-01

    Viscosity, shear modulus and other viscoelastic properties of multicomponent polymer blends are predicted from behavior of individual components, using a mathematical model. Model is extension of two-component-blend model based on Rouse-Bueche-Zimm theory of polymer viscoelasticity. Extension assumes that probabilities of forming various possible intracomponent and intercomponent entanglements among polymer molecules are proportional to relative abundances of components.

  4. White polymer light-emitting diode based on polymer blending

    International Nuclear Information System (INIS)

    Lee, Yong Kyun; Kwon, Soon Kab; Kim, Jun Young; Park, Tae Jin; Song, Dae Ho; Kwon, Jang Hyuk; Choo, Dong Jun; Jang, Jin; Jin, Jae Kyu; You, Hong

    2006-01-01

    A series of white polymer light emitting devices have been fabricated by using a polymer blending system of polyfluorene-based blue and MEH-PPV red polymers. A device structure of ITO/PEDOT:PSS/polymer/LiF/Al was employed. The white polymer device exhibited a current efficiency of 4.33 cd/A (4,816 cd/m 2 , Q.E. = 1.9 %) and a maximum luminance of 21,430 cd/m 2 at 9.2 V. The CIE coordinates were (0.35, 0.37) at 5 V and (0.29, 0.30) at 9 V.

  5. Fingerprinting Molecular Relaxation in Deformed Polymers

    Science.gov (United States)

    Wang, Zhe; Lam, Christopher N.; Chen, Wei-Ren; Wang, Weiyu; Liu, Jianning; Liu, Yun; Porcar, Lionel; Stanley, Christopher B.; Zhao, Zhichen; Hong, Kunlun; Wang, Yangyang

    2017-07-01

    The flow and deformation of macromolecules is ubiquitous in nature and industry, and an understanding of this phenomenon at both macroscopic and microscopic length scales is of fundamental and practical importance. Here, we present the formulation of a general mathematical framework, which could be used to extract, from scattering experiments, the molecular relaxation of deformed polymers. By combining and modestly extending several key conceptual ingredients in the literature, we show how the anisotropic single-chain structure factor can be decomposed by spherical harmonics and experimentally reconstructed from its cross sections on the scattering planes. The resulting wave-number-dependent expansion coefficients constitute a characteristic fingerprint of the macromolecular deformation, permitting detailed examinations of polymer dynamics at the microscopic level. We apply this approach to survey a long-standing problem in polymer physics regarding the molecular relaxation in entangled polymers after a large step deformation. The classical tube theory of Doi and Edwards predicts a fast chain retraction process immediately after the deformation, followed by a slow orientation relaxation through the reptation mechanism. This chain retraction hypothesis, which is the keystone of the tube theory for macromolecular flow and deformation, is critically examined by analyzing the fine features of the two-dimensional anisotropic spectra from small-angle neutron scattering by entangled polystyrenes. We show that the unique scattering patterns associated with the chain retraction mechanism are not experimentally observed. This result calls for a fundamental revision of the current theoretical picture for nonlinear rheological behavior of entangled polymeric liquids.

  6. Fingerprinting Molecular Relaxation in Deformed Polymers

    Directory of Open Access Journals (Sweden)

    Zhe Wang

    2017-07-01

    Full Text Available The flow and deformation of macromolecules is ubiquitous in nature and industry, and an understanding of this phenomenon at both macroscopic and microscopic length scales is of fundamental and practical importance. Here, we present the formulation of a general mathematical framework, which could be used to extract, from scattering experiments, the molecular relaxation of deformed polymers. By combining and modestly extending several key conceptual ingredients in the literature, we show how the anisotropic single-chain structure factor can be decomposed by spherical harmonics and experimentally reconstructed from its cross sections on the scattering planes. The resulting wave-number-dependent expansion coefficients constitute a characteristic fingerprint of the macromolecular deformation, permitting detailed examinations of polymer dynamics at the microscopic level. We apply this approach to survey a long-standing problem in polymer physics regarding the molecular relaxation in entangled polymers after a large step deformation. The classical tube theory of Doi and Edwards predicts a fast chain retraction process immediately after the deformation, followed by a slow orientation relaxation through the reptation mechanism. This chain retraction hypothesis, which is the keystone of the tube theory for macromolecular flow and deformation, is critically examined by analyzing the fine features of the two-dimensional anisotropic spectra from small-angle neutron scattering by entangled polystyrenes. We show that the unique scattering patterns associated with the chain retraction mechanism are not experimentally observed. This result calls for a fundamental revision of the current theoretical picture for nonlinear rheological behavior of entangled polymeric liquids.

  7. Metallization of Various Polymers by Cold Spray

    Science.gov (United States)

    Che, Hanqing; Chu, Xin; Vo, Phuong; Yue, Stephen

    2018-01-01

    Previous results have shown that metallic coatings can be successfully cold sprayed onto polymeric substrates. This paper studies the cold sprayability of various metal powders on different polymeric substrates. Five different substrates were used, including carbon fiber reinforced polymer (CFRP), acrylonitrile butadiene styrene (ABS), polyether ether ketone (PEEK), polyethylenimine (PEI); mild steel was also used as a benchmark substrate. The CFRP used in this work has a thermosetting matrix, and the ABS, PEEK and PEI are all thermoplastic polymers, with different glass transition temperatures as well as a number of distinct mechanical properties. Three metal powders, tin, copper and iron, were cold sprayed with both a low-pressure system and a high-pressure system at various conditions. In general, cold spray on the thermoplastic polymers rendered more positive results than the thermosetting polymers, due to the local thermal softening mechanism in the thermoplastics. Thick copper coatings were successfully deposited on PEEK and PEI. Based on the results, a method is proposed to determine the feasibility and deposition window of cold spraying specific metal powder/polymeric substrate combinations.

  8. Preparation, Single-Molecule Manipulation, and Energy Transfer Investigation of a Polyfluorene-graft-DNA polymer.

    Science.gov (United States)

    Madsen, Mikael; Christensen, Rasmus S; Krissanaprasit, Abhichart; Bakke, Mette R; Riber, Camilla F; Nielsen, Karina S; Zelikin, Alexander N; Gothelf, Kurt V

    2017-08-04

    Conjugated polymers have been intensively studied due to their unique optical and electronic properties combined with their physical flexibility and scalable bottom up synthesis. Although the bulk qualities of conjugated polymers have been extensively utilized in research and industry, the ability to handle and manipulate conjugated polymers at the nanoscale lacks significantly behind. Here, the toolbox for controlled manipulation of conjugated polymers was expanded through the synthesis of a polyfluorene-DNA graft-type polymer (poly(F-DNA)). The polymer possesses the characteristics associated with the conjugated polyfluorene backbone, but the protruding single-stranded DNA provides the material with an exceptional addressability. This study demonstrates controlled single-molecule patterning of poly(F-DNA), as well as energy transfer between two different polymer-DNA conjugates. Finally, highly efficient DNA-directed quenching of polyfluorene fluorescence was shown. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Multifunctional Nanotube Polymer Nanocomposites for Aerospace Applications: Adhesion between SWCNT and Polymer Matrix

    Science.gov (United States)

    Park, Cheol; Wise, Kristopher E.; Kang, Jin Ho; Kim, Jae-Woo; Sauti, Godfrey; Lowther, Sharon E.; Lillehei, Peter T.; Smith, Michael W.; Siochi, Emilie J.; Harrison, Joycelyn S.; hide

    2008-01-01

    Multifunctional structural materials can enable a novel design space for advanced aerospace structures. A promising route to multifunctionality is the use of nanotubes possessing the desired combination of properties to enhance the characteristics of structural polymers. Recent nanotube-polymer nanocomposite studies have revealed that these materials have the potential to provide structural integrity as well as sensing and/or actuation capabilities. Judicious selection or modification of the polymer matrix to promote donor acceptor and/or dispersion interactions can improve adhesion at the interface between the nanotubes and the polymer matrix significantly. The effect of nanotube incorporation on the modulus and toughness of the polymer matrix will be presented. Very small loadings of single wall nanotubes in a polyimide matrix yield an effective sensor material that responds to strain, stress, pressure, and temperature. These materials also exhibit significant actuation in response to applied electric fields. The objective of this work is to demonstrate that physical properties of multifunctional material systems can be tailored for specific applications by controlling nanotube treatment (different types of nanotubes), concentration, and degree of alignment.

  10. based gel polymer electrolytes

    Indian Academy of Sciences (India)

    Bull. Mater. Sci., Vol. 29, No. 7, December 2006, pp. 673–678. © Indian Academy of Sciences. 673. Investigation on poly (vinylidene fluoride) based gel polymer electrolytes ... (Alamgir and Abraham 1993; Sukeshini et al 1996; Ra- jendran and Uma ... Yang et al 1996; Ramesh and Arof 2001) and such elec- trolytes exhibit ...

  11. Raw and renewable polymers

    CSIR Research Space (South Africa)

    Joseph, S

    2010-01-01

    Full Text Available with enhanced support for global sustainability. High performance plastics are the outcome of continuous research over the last few decades. The real challenge of renewable polymers lies in finding applications, which will result in mass production, and price...

  12. Knots in polymers

    Indian Academy of Sciences (India)

    Knots and topological entanglements play an important role in the statistical mechanics of polymers. While topological entanglement is a global property, it is possible to study the size of a knotted region both numerically and analytically. It can be shown that long-range repulsive interactions, as well as entropy favor small ...

  13. Conformational properties of polymers

    Indian Academy of Sciences (India)

    Abstract. We discuss exact enumeration technique and its application to polymers and biopolymers. Using this method one can obtain phase diagram in thermodynamic limit. The method works quite well in describing the outcomes of single molecule force spectroscopy results where finite size effects play a crucial role.

  14. Polymers of phenylenediamines

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav

    2015-01-01

    Roč. 41, February (2015), s. 1-31 ISSN 0079-6700 R&D Projects: GA ČR(CZ) GA13-00270S Institutional support: RVO:61389013 Keywords : polyphenylenediamine * phenylenediamine * conducting polymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 27.184, year: 2015

  15. Polyester polymer concrete overlay.

    Science.gov (United States)

    2013-01-01

    Polyester polymer concrete (PPC) was used in a trial application on a section of pavement that suffers from extensive studded tire wear. The purpose of the trial section is to determine if PPC is a possible repair strategy for this type of pavement d...

  16. Surface tension of polymer melts - experimental investigations of its effect on polymer-polymer adhesion

    DEFF Research Database (Denmark)

    Jankova Atanasova, Katja; Islam, Mohammad Aminul; Hansen, Hans Nørgaard

    -polymer bond strength during two component polymer processing. Polymer materials PS, POM, ABS, PEl, PEEK and PC are chosen for the investigation. Pendant drop method showed that in case of PS and POM, the melt surface tension was decreased with increasing temperature. The substrate surface energies...

  17. Surface tension of polymer melts - experimental investigations of its effects on polymer-polymer adhesion

    DEFF Research Database (Denmark)

    Islam, Mohammad Aminul; Jankova Atanasova, Katja; Hansen, Hans Nørgaard

    -polymer bond strength during two component polymer processing. Polymer materials PS, POM, ABS, PEI, PEEK and PC are chosen for the investigation. Pendant drop method showed that in case of PS and POM, the melt surface tension was decreased with increasing temperature. The substrate surface energies...

  18. Gel polymer electrolytes for batteries

    Science.gov (United States)

    Balsara, Nitash Pervez; Eitouni, Hany Basam; Gur, Ilan; Singh, Mohit; Hudson, William

    2014-11-18

    Nanostructured gel polymer electrolytes that have both high ionic conductivity and high mechanical strength are disclosed. The electrolytes have at least two domains--one domain contains an ionically-conductive gel polymer and the other domain contains a rigid polymer that provides structure for the electrolyte. The domains are formed by block copolymers. The first block provides a polymer matrix that may or may not be conductive on by itself, but that can soak up a liquid electrolyte, thereby making a gel. An exemplary nanostructured gel polymer electrolyte has an ionic conductivity of at least 1.times.10.sup.-4 S cm.sup.-1 at 25.degree. C.

  19. Frictional properties of confined polymers

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, Vladimir N; Persson, Bo N J

    2008-01-01

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: a) polymer sliding against a hard substrate, and b) polymer sliding on polymer. In the first setup the shear stresses are relatively...... independent of molecular length. For polymer sliding on polymer the friction is significantly larger, and dependent on the molecular chain length. In both cases, the shear stresses are proportional to the squeezing pressure and finite at zero load, indicating an adhesional contribution to the friction force...

  20. Conducting Polymers for Neutron Detection

    International Nuclear Information System (INIS)

    Clare Kimblin; Kirk Miller; Bob Vogel; Bill Quam; Harry McHugh; Glen Anthony; Steve Jones; Mike Grover

    2007-01-01

    Conjugated polymers have emerged as an attractive technology for large-area electronic applications. As organic semiconductors, they can be used to make large-area arrays of diodes or transistors using fabrication techniques developed for polymer coatings, such as spraying and screen-printing. We have demonstrated both neutron and alpha detection using diodes made from conjugated polymers and have done preliminary work to integrate a boron carbide layer into the conventional polymer device structure to capture thermal neutrons. The polymer devices appear to be insensitive to gamma rays, due to their small physical thickness and low atomic number

  1. Conducting Polymers for Neutron Detection

    Energy Technology Data Exchange (ETDEWEB)

    Kimblin, Clare; Miller, Kirk; Vogel, Bob; Quam, Bill; McHugh, Harry; Anthony, Glen; Mike, Grover

    2007-12-01

    Conjugated polymers have emerged as an attractive technology for large-area electronic applications. As organic semiconductors, they can be used to make large-area arrays of diodes or transistors using fabrication techniques developed for polymer coatings, such as spraying and screen-printing. We have demonstrated both neutron and alpha detection using diodes made from conjugated polymers and have done preliminary work to integrate a boron carbide layer into the conventional polymer device structure to capture thermal neutrons. The polymer devices appear to be insensitive to gamma rays, due to their small physical thickness and low atomic number.

  2. Dissolving Polymers in Ionic Liquids.

    Science.gov (United States)

    Hoagland, David; Harner, John

    2009-03-01

    Dissolution and phase behavior of polymers in ionic liquids have been assessed by solution characterization techniques such as intrinsic viscosity and light scattering (static and dynamic). Elevated viscosity proved the greatest obstacle. As yet, whether principles standard to conventional polymer solutions apply to ionic liquid solutions is uncertain, especially for polymers such as polyelectrolytes and hydrophilic block copolymers that may specifically interact with ionic liquid anions or cations. For flexible polyelectrolytes (polymers releasing counterions into high dielectric solvents), characterization in ionic liquids suggests behaviors more typical of neutral polymer. Coil sizes and conformations are approximately the same as in aqueous buffer. Further, several globular proteins dissolve in a hydrophilic ionic liquid with conformations analogous to those in buffer. General principles of solubility, however, remain unclear, making predictions of which polymer dissolves in which ionic liquid difficult; several otherwise intractable polymers (e.g., cellulose, polyvinyl alcohol) dissolve and can be efficiently functionalized in ionic liquids.

  3. Adsorption and flocculation by polymers and polymer mixtures.

    Science.gov (United States)

    Gregory, John; Barany, Sandor

    2011-11-14

    Polymers of various types are in widespread use as flocculants in several industries. In most cases, polymer adsorption is an essential prerequisite for flocculation and kinetic aspects are very important. The rates of polymer adsorption and of re-conformation (relaxation) of adsorbed chains are key factors that influence the performance of flocculants and their mode of action. Polyelectrolytes often tend to adopt a rather flat adsorbed configuration and in this state their action is mainly through charge effects, including 'electrostatic patch' attraction. When the relaxation rate is quite low, particle collisions may occur while the adsorbed chains are still in an extended state and flocculation by polymer bridging may occur. These effects are now well understood and supported by much experimental evidence. In recent years there has been considerable interest in the use of multi-component flocculants, especially dual-polymer systems. In the latter case, there can be significant advantages over the use of single polymers. Despite some complications, there is a broad understanding of the action of dual polymer systems. In many cases the sequence of addition of the polymers is important and the pre-adsorbed polymer can have two important effects: providing adsorption sites for the second polymer or causing a more extended adsorbed conformation as a result of 'site blocking'. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. New method for preparing a liquid crystal polymer that exhibits linearly polarized white fluorescence

    International Nuclear Information System (INIS)

    Zheng Shijun; Kun, Wang; Kobayashi, Takaomi

    2011-01-01

    With the aim of developing a single-chain white-light-emitting polymer, liquid crystal (LC) polymers with a shish-kebab-type moiety on their cross-conjugated (p-phenylene)s-poly(p-phenylenevinylene)s main chain were synthesized by Gilch polymerization. They were characterized by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and polarizing optical microscopy (POM). 1 H-NMR indicated that the polymers had a shish-kebab structure, which strongly suppressed the formation of structural defects in the polymers. DSC revealed that the polymers had thermotropic LC properties, indicating that the LC polymers were enantiotropic. XRD showed that the polymers had a mesophase, which implies that they were in a smectic LC phase. A polymer with 'kebabs' of 2,5-bis(4'-alkoxyphenyl)benzene was combined with an aligned polyimide film with orientated microgrooves. The polymer main chain was aligned due to the orientation of the 'kebabs' of the uniform cross-conjugated structure. It lay between the kebabs and the 'shish' of the polymer main chains. The aligned polymer main chain emitted yellow light while and the oriented LC side chains emitted blue light emission. These two emissions resulted in linearly polarized white fluorescence.

  5. Recent Development in ITO-free Flexible Polymer Solar Cells

    Directory of Open Access Journals (Sweden)

    Shudi Lu

    2017-12-01

    Full Text Available Polymer solar cells have shown good prospect for development due to their advantages of low-cost, light-weight, solution processable fabrication, and mechanical flexibility. Their compatibility with the industrial roll-to-roll manufacturing process makes it superior to other kind of solar cells. Normally, indium tin oxide (ITO is adopted as the transparent electrode in polymer solar cells, which combines good conductivity and transparency. However, some intrinsic weaknesses of ITO restrict its large scale applications in the future, including a high fabrication price using high temperature vacuum deposition method, scarcity of indium, brittleness and scaling up of resistance with the increase of area. Some substitutes to ITO have emerged in recent years, which can be used in flexible polymer solar cells. This article provides the review on recent progress using other transparent electrodes, including carbon nanotubes, graphene, metal nanowires and nanogrids, conductive polymer, and some other electrodes. Device stability is also discussed briefly.

  6. Photoreconfigurable polymers for biomedical applications: chemistry and macromolecular engineering.

    Science.gov (United States)

    Zhu, Congcong; Ninh, Chi; Bettinger, Christopher J

    2014-10-13

    Stimuli-responsive polymers play an important role in many biomedical technologies. Light responsive polymers are particularly desirable because the parameters of irradiated light and diverse photoactive chemistries produce a large number of combinations between functional materials and associated stimuli. This Review summarizes recent advances in utilizing photoactive chemistries in macromolecules for prospective use in biomedical applications. Special focus is granted to selection criterion when choosing photofunctional groups. Synthetic strategies to incorporate these functionalities into polymers and networks with different topologies are also highlighted herein. Prospective applications of these materials are discussed including programmable matrices for controlled release, dynamic scaffolds for tissue engineering, and functional coatings for medical devices. The article concludes by summarizing the state of the art in photoresponsive polymers for biomedical applications including current challenges and future opportunities.

  7. Fe{sub 2}O{sub 3}-loaded activated carbon fiber/polymer materials and their photocatalytic activity for methylene blue mineralization by combined heterogeneous-homogeneous photocatalytic processes

    Energy Technology Data Exchange (ETDEWEB)

    Kadirova, Zukhra C., E-mail: zuhra_kadirova@yahoo.com [Institute of General and Inorganic Chemistry, Uzbekistan Academy of Sciences, Mirzo Ulugbek Street 77a, Tashkent 100170 (Uzbekistan); Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502 (Japan); Hojamberdiev, Mirabbos, E-mail: hmirabbos@hotmail.com [Department of Natural and Mathematic Sciences, Turin Polytechnic University in Tashkent, Kichik Halqa Yo’li 17, Tashkent 100095 (Uzbekistan); Katsumata, Ken-Ichi [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502 (Japan); Isobe, Toshihiro [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro, Tokyo 152-8552 (Japan); Matsushita, Nobuhiro [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502 (Japan); Nakajima, Akira [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro, Tokyo 152-8552 (Japan); Okada, Kiyoshi [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502 (Japan)

    2017-04-30

    Highlights: • Fe{sub 2}O{sub 3}-activated carbon felts was prepared for adsorption-photodegradation of dyes. • Simultaneous mineralization of MB and oxalic acid occurred under UV-irradiation. • Methylene blue adsorption was better fitted to the Langmuir model. • Increasing amount of Fe{sub 2}O{sub 3} decreased the S{sub BET} and methylene blue adsorption capacity. • Photodegraded amount of MB was increased with increasing the Fe{sub 2}O{sub 3} content. - Abstract: Fe{sub 2}O{sub 3}-supported activated carbon felts (Fe-ACFTs) were prepared by impregnating the felts consisted of activated carbon fibers (ACFs) with either polyester fibers (PS-A20) or polyethylene pulp (PE-W15) in Fe(III) nitrate solution and calcination at 250 °C for 1 h. The prepared Fe-ACFTs with 31–35 wt% Fe were characterized by N{sub 2}-adsorption, scanning electron microscopy, and X-ray diffraction. The Fe-ACFT(PS-A20) samples with 5–31 wt% Fe were microporous with specific surface areas (S{sub BET}) ranging from 750 to 150 m{sup 2}/g, whereas the Fe-ACFT(PE-W15) samples with 2–35 wt% Fe were mesoporous with S{sub BET} ranging from 830 to 320 m{sup 2}/g. The deposition of iron oxide resulted in a decrease in the S{sub BET} and methylene blue (MB) adsorption capacity while increasing the photodegradation of MB. The optimum MB degradation conditions included 0.98 mM oxalic acid, pH = 3, 0.02–0.05 mM MB, and 100 mg/L photocatalyst. The negative impact of MB desorption during the photodegradation reaction was more pronounced for mesoporous PE-W15 samples and can be neglected by adding oxalic acid in cyclic experiments. Almost complete and simultaneous mineralization of oxalate and MB was achieved by the combined heterogeneous-homogeneous photocatalytic processes. The leached Fe ions in aqueous solution [Fe{sup 3+}]{sub f} were measured after 60 min for every cycle and found to be about 2 ppm in all four successive cycles. The developed photocatalytic materials have shown good

  8. Controlled release of tocopherols from polymer blend films

    Science.gov (United States)

    Obinata, Noe

    Controlled release packaging has great potential to increase storage stability of foods by releasing active compounds into foods continuously over time. However, a major limitation in development of this technology is the inability to control the release and provide rates useful for long term storage of foods. Better understanding of the factors affecting active compound release is needed to overcome this limitation. The objective of this research was to investigate the relationship between polymer composition, polymer processing method, polymer morphology, and release properties of active compounds, and to provide proof of principle that compound release is controlled by film morphology. A natural antioxidant, tocopherol was used as a model active compound because it is natural, effective, heat stable, and soluble in most packaging polymers. Polymer blend films were produced from combination of linear low density polyethylene (LLDPE) and high density polyethylene (HDPE), polypropylene (PP), or polystyrene (PS) with 3000 ppm mixed tocopherols using conventional blending method and innovative blending method, smart blending with a novel mixer using chaotic advection. Film morphologies were visualized with scanning electron microscopy (SEM). Release of tocopherols into 95% ethanol as a food simulant was measured by UV/Visible spectrophotometry or HPLC, and diffusivity of tocopherols in the polymers was estimated from this data. Polymer composition (blend proportions) and processing methods have major effects on film morphology. Four different types of morphologies, dispersed, co-continuous, fiber, and multilayer structures were developed by either conventional extrusion or smart blending. With smart blending of fixed polymer compositions, different morphologies were progressively developed with fixed polymer composition as the number of rod rotations increased, providing a way to separate effects of polymer composition and morphology. The different morphologies

  9. Enhanced Performance of Inverted Polymer Solar Cells by Combining ZnO Nanoparticles and Poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctyfluorene)] as Electron Transport Layer.

    Science.gov (United States)

    Han, Changfeng; Cheng, Yuanyuan; Chen, Ling; Qian, Lei; Yang, Ziyan; Xue, Wei; Zhang, Ting; Yang, Yixing; Cao, Weiran

    2016-02-10

    A highly efficient inverted polymer solar cell (PSC) has been successfully demonstrated by using a ZnO nanoparticle (NP) and poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctyfluorene)] (PFN) bilayer structure as an effective electron collecting layer. This ZnO/PFN bilayer structure is designed to combine the advantages of both ZnO and PFN, based on the performance comparison of ZnO-only, PFN-only, and ZnO/PFN bilayer devices in our work. ZnO NPs can serve as an efficient electron transport and buffer layer for reduced series resistance, while the PFN interlayer can improve the energy level alignment of devices through the formation of an interfacial dipole. With the enhanced electron extraction induced by the ZnO/PFN bilayer structure and PTB7:ICBA:PC71BM ternary system, the corresponding inverted PSC device shows a high PCE of 9.3%, which is more than a 15% improvement compared to the ZnO- or PFN-only devices.

  10. Controlling Film Morphology in Conjugated Polymer

    Science.gov (United States)

    Park, Lee Y.; Munro, Andrea M.; Ginger, David S.

    2009-01-01

    We study the effects of patterned surface chemistry on the microscale and nanoscale morphology of solution-processed donor/acceptor polymer-blend films. Focusing on combinations of interest in polymer solar cells, we demonstrate that patterned surface chemistry can be used to tailor the film morphology of blends of semiconducting polymers such as poly-[2-(3,7-dimethyloctyloxy)-5-methoxy-p-phenylenevinylene] (MDMO-PPV), poly-3-hexylthiophene (P3HT), poly[(9,9-dioctylflorenyl-2,7-diyl)-co-benzothiadiazole)] (F8BT), and poly(9,9-dioctylfluorene-co-bis-N,N’-(4-butylphenyl)-bis-N,N’-phenyl-1,4-phenylendiamine) (PFB) with the fullerene derivative, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). We present a method for generating patterned, fullerene-terminated monolayers on gold surfaces, and use microcontact printing and Dip-Pen Nanolithography (DPN) to pattern alkanethiols with both micro- and nanoscale features. After patterning with fullerenes and other functional groups, we backfill the rest of the surface with a variety of thiols to prepare substrates with periodic variations in surface chemistry. Spin coating polymer:PCBM films onto these substrates, followed by thermal annealing under nitrogen, leads to the formation of structured polymer films. We characterize these films with Atomic Force Microscopy (AFM), Raman spectroscopy, and fluorescence microscopy. The surface patterns are effective in guiding phase separation in all of the polymer:PCBM systems investigated, and lead to a rich variety of film morphologies that are inaccessible with unpatterned substrates. We demonstrate our ability to guide pattern formation in films thick enough of be of interest for actual device applications (up to 200 nm in thickness) using feature sizes as small as 100 nm. Finally, we show that the surface chemistry can lead to variations in film morphology on length scales significantly smaller than those used in generating the original surface patterns. The variety of

  11. Thermodynamics and mechanics of photochemcially reacting polymers

    Science.gov (United States)

    Long, Rong; Qi, H. Jerry; Dunn, Martin L.

    2013-11-01

    We develop a thermodynamics and mechanics theory for polymers that when irradiated with light, undergo photochemical reactions that alter their macromolecular structure, e.g., by bond breaking and/or reformation, and in turn affect their mechanical and physical behavior. This emerging class of highly-engineered active materials shows great promise for myriad applications and is a subset of a broader class of polymers with covalent bonds that can be dynamically tuned with various environmental stimuli. We formulate a general thermodynamic and kinetic framework to model the complex photochemical-thermal-mechanical coupling in these materials. Our theory considers the behavior of a polymer that is subjected to the combination of mechanical and thermal loading while simultaneously irradiated by light with multiple frequency components and directions. We introduce an approach to model the photochemical reactions that can change the network topology, resulting chemical species transport, heat conduction and finite deformation. We describe the interaction of the material with light via a radiometric description and show how it can be linked to a full electromagnetic treatment when appropriate and if desired. Our approach is sufficiently general to permit the modeling of various materials that operate via different photochemical reaction mechanisms. After formulating the general theory, we specialize it to a polymer that when irradiated with light undergoes a series of photochemical reactions that cause chain scission and reformation which continuously rearrange the polymer network into a stress-free configuration. Based on the operant physical mechanisms we develop a constitutive model using a polymer chain decomposition and evolution approach to track the molecular structure changes during simultaneous irradiation and mechanical loading. In the special case of isothermal conditions with monochromatic and unidirectional irradiation, we recover a previous model based on

  12. Polymer physics of nuclear organization and function

    Energy Technology Data Exchange (ETDEWEB)

    Amitai, A. [Department of Chemical Engineering, Institute for Medical Engineering & Science, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Holcman, D., E-mail: david.holcman@ens.fr [Department of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge, Churchill College, CB30DS, Cambridge (United Kingdom); Ecole Normale Superieure, Paris (France)

    2017-03-23

    We review here recent progress to link the nuclear organization to its function, based on elementary physical processes such as diffusion, polymer dynamics of DNA, chromatin and the search mechanism for a small target by double-stranded DNA (dsDNA) break. These physical models and their analysis make it possible to compute critical rates involved in cell reorganization timing, which depend on many parameters. In the framework of polymer models, various empirical observations are interpreted as anomalous diffusion of chromatin at various time scales. The reviewed theoretical approaches offer a framework for extracting features, biophysical parameters, predictions, and so on, based on a large variety of experimental data, such as chromosomal capture data, single particle trajectories, and more. Combining theoretical approaches with live cell microscopy data should unveil some of the still unexplained behavior of the nucleus in carrying out some of its key function involved in survival, DNA repair or gene activation.

  13. High temperature chemically resistant polymer concrete

    Science.gov (United States)

    Sugama, T.; Kukacka, L.E.

    High temperature chemically resistant, non-aqueous polymer concrete composites consist of about 12 to 20% by weight of a water-insoluble polymer binder. The binder is polymerized in situ from a liquid vinyl-type monomer or mixture of vinyl containing monomers such as triallylcyanurate, styrene, acrylonitrile, acrylamide, methacrylamide, methyl-methacrylate, trimethylolpropane trimethacrylate and divinyl benzene. About 5 to 40% by weight of a reactive inorganic filler selected from the group consisting of tricalcium silicate and dicalcium silicate and mixtures containing less than 2% free lime, and about 48 to 83% by weight of silica sand/ and a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other orgaic peroxides and combinations to initiate polymerization of the monomer in the presence of the inorganic filers are used.

  14. Characterization of polymer surface structure and surface mechanical behaviour by sum frequency generation surface vibrational spectroscopy and atomic force microscopy

    International Nuclear Information System (INIS)

    Opdahl, Aric; Koffas, Telly S; Amitay-Sadovsky, Ella; Kim, Joonyeong; Somorjai, Gabor A

    2004-01-01

    Sum frequency generation (SFG) vibrational spectroscopy and atomic force microscopy (AFM) have been used to study polymer surface structure and surface mechanical behaviour, specifically to study the relationships between the surface properties of polymers and their bulk compositions and the environment to which the polymer is exposed. The combination of SFG surface vibrational spectroscopy and AFM has been used to study surface segregation behaviour of polyolefin blends at the polymer/air and polymer/solid interfaces. SFG surface vibrational spectroscopy and AFM experiments have also been performed to characterize the properties of polymer/liquid and polymer/polymer interfaces, focusing on hydrogel materials. A method was developed to study the surface properties of hydrogel contact lens materials at various hydration conditions. Finally, the effect of mechanical stretching on the surface composition and surface mechanical behaviour of phase-separated polyurethanes, used in biomedical implant devices, has been studied by both SFG surface vibrational spectroscopy and AFM. (topical review)

  15. Polymer Physics Prize Talk

    Science.gov (United States)

    Olvera de La Cruz, Monica

    Polymer electrolytes have been particularly difficult to describe theoretically given the large number of disparate length scales involved in determining their physical properties. The Debye length, the Bjerrum length, the ion size, the chain length, and the distance between the charges along their backbones determine their structure and their response to external fields. We have developed an approach that uses multi-scale calculations with the capability of demonstrating the phase behavior of polymer electrolytes and of providing a conceptual understanding of how charge dictates nano-scale structure formation. Moreover, our molecular dynamics simulations have provided an understanding of the coupling of their conformation to their dynamics, which is crucial to design self-assembling materials, as well as to explore the dynamics of complex electrolytes for energy storage and conversion applications.

  16. Dielectric Actuation of Polymers

    Science.gov (United States)

    Niu, Xiaofan

    Dielectric polymers are widely used in a plurality of applications, such as electrical insulation, dielectric capacitors, and electromechanical actuators. Dielectric polymers with large strain deformations under an electric field are named dielectric elastomers (DE), because of their relative low modulus, high elongation at break, and outstanding resilience. Dielectric elastomer actuators (DEA) are superior to traditional transducers as a muscle-like technology: large strains, high energy densities, high coupling efficiency, quiet operation, and light weight. One focus of this dissertation is on the design of DE materials with high performance and easy processing. UV radiation curing of reactive species is studied as a generic synthesis methodology to provide a platform for material scientists to customize their own DE materials. Oligomers/monomers, crosslinkers, and other additives are mixed and cured at appropriate ratios to control the stress-strain response, suppress electromechanical instability of the resulting polymers, and provide stable actuation strains larger than 100% and energy densities higher than 1 J/g. The processing is largely simplified in the new material system by removal of the prestretching step. Multilayer stack actuators with 11% linear strain are demonstrated in a procedure fully compatible with industrial production. A multifunctional DE derivative material, bistable electroactive polymer (BSEP), is invented enabling repeatable rigid-to-rigid deformation without bulky external structures. Bistable actuation allows the polymer actuator to have two distinct states that can support external load without device failure. Plasticizers are used to lower the glass transition temperature to 45 °C. Interpenetrating polymer network structure is established inside the BSEP to suppress electromechanical instability, providing a breakdown field of 194 MV/m and a stable bistable strain as large as 228% with a 97% strain fixity. The application of BSEP

  17. Polymer/Clay Nanocomposites

    Directory of Open Access Journals (Sweden)

    M. Mehrdad shokrieh

    2007-06-01

    Full Text Available Nanocomposite materials have recently attracted increasing interests in the field of modelling. Finite element modelling can be used for computation of bulk properties of polymer/clay nanocomposites. In this study, by   considering the structure of a nano-composite material, a quasi real model is proposed. The model has been used to predict the elastic constants by selection of suitable elements and boundary conditions. The effects of nano-structural parameters on the mechanical properties of a polymer/clay nano-composite are studied. The geometrical overlap of particles, horizontal distance between particles, length of particles and nano-clay volume fraction are defined as functions of the nano-structural parameters and their effects on mechanical properties of nano-composites are studied by a finite element modelling technique.

  18. Mesoscale Polymer Assemblies

    Science.gov (United States)

    Choudhary, Satyan; Pham, Jonathan; Crosby, Alfred

    2015-03-01

    Materials encompassing structural hierarchy and multi-functionality allow for remarkable physical properties across different length scales. Mesoscale Polymer (MSP) assemblies provide a critical link, from nanometer to centimeter scales, in the definition of such hierarchical structures. Recent focus has been on exploiting these MSP assemblies for optical, electronic, photonics and biological applications. We demonstrate a novel fabrication method for MSP assemblies. Current fabrication methods restrict the length scale and volume of such assemblies. A new method developed uses a simple piezo-actuated motion for de-pinning of a polymer solution trapped by capillary forces between a flexible blade and a rigid substrate. The advantages of new method include ability to make MSP of monodisperse length and to fabricate sufficient volumes of MSP to study their physical properties and functionality in liquid dispersions. We demonstrate the application of MSP as filler for soft materials, providing rheological studies of the MSP with surrounding matrices.

  19. Understanding Molecular Interactions within Chemically Selective Layered Polymer Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Gary J. Blanchard

    2009-06-30

    This work focuses on two broad issues. These are (1) the molecular origin of the chemical selectivity achieved with ultrathin polymer multilayers, and (2) how the viscoelastic properties of the polymer layers are affected by exposure to solvent and analytes. These issues are inter-related, and to understand them we need to design experiments that probe both the energetic and kinetic aspects of interfacial adsorption processes. This project focuses on controling the chemical structure, thickness, morphology and sequential ordering of polymer layers bound to interfaces using maleimide-vinyl ether and closely related alternating copolymerization chemistry and efficient covalent cross-linking reactions that allow for layer-by-layer polymer deposition. This chemistry has been developed during the funding cycle of this Grant. We have measure the equilibrium constants for interactions between specific layers within the polymer interfaces and size-controlled, surface-functionalized gold nanoparticles. The ability to control both size and functionality of gold nanoparticle model analytes allows us to evaluate the average “pore size” that characterizes our polymer films. We have measured the “bulk” viscosity and shear modulus of the ultrathin polymer films as a function of solvent overlayer identity using quartz crystal microbalance complex impedance measurements. We have measured microscopic viscosity at specific locations within the layered polymer interfaces with time-resolved fluorescence lifetime and depolarization techniques. We combine polymer, cross-linking and nanoparticle synthetic expertise with a host of characterization techniques, including QCM gravimetry and complex impedance analysis, steady state and time-resolved spectroscopies.

  20. Conjugated polymer nanoparticles, methods of using, and methods of making

    KAUST Repository

    Habuchi, Satoshi

    2017-03-16

    Embodiments of the present disclosure provide for conjugated polymer nanoparticle, method of making conjugated polymer nanoparticles, method of using conjugated polymer nanoparticle, polymers, and the like.

  1. Knots in polymers

    Indian Academy of Sciences (India)

    Ey; 05.40.Fb; 02.10.Kn; 82.35.Rs. 1. Introduction. Knots and links naturally appear in long polymers [1] and play an important role in biological processes [2]. The simplest statistical–mechanical model of a ..... [6] A D Bates and A Maxwell, DNA Topology (IRL Press, Oxford, 1993). [7] P Pieranski, S Przyby l and A Stasiak, ...

  2. Electrochemical polymer electrolyte membranes

    CERN Document Server

    Fang, Jianhua; Wilkinson, David P

    2015-01-01

    Electrochemical Polymer Electrolyte Membranes covers PEMs from fundamentals to applications, describing their structure, properties, characterization, synthesis, and use in electrochemical energy storage and solar energy conversion technologies. Featuring chapters authored by leading experts from academia and industry, this authoritative text: Discusses cutting-edge methodologies in PEM material selection and fabricationPoints out important challenges in developing PEMs and recommends mitigation strategies to improve PEM performanceAnalyzes the cur

  3. Solid polymer electrolytes

    Science.gov (United States)

    Abraham, Kuzhikalail M.; Alamgir, Mohamed; Choe, Hyoun S.

    1995-01-01

    This invention relates to Li ion (Li.sup.+) conductive solid polymer electrolytes composed of poly(vinyl sulfone) and lithium salts, and their use in all-solid-state rechargeable lithium ion batteries. The lithium salts comprise low lattice energy lithium salts such as LiN(CF.sub.3 SO.sub.2).sub.2, LiAsF.sub.6, and LiClO.sub.4.

  4. Dynamics of polymers

    Energy Technology Data Exchange (ETDEWEB)

    Buchenau, U. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energieverfahrenstechnik

    1996-11-01

    Neutron scattering from amorphous polymers allows to switch from incoherent to coherent scattering in the same substance. The power of the tool for the study of the picosecond dynamics of disordered matter is illustrated for polybutadiene, polycarbonate and polystyrene. The results suggest a mixture of sound waves and localized modes, strongly interacting with each other, in the picosecond range. (author) 8 figs., tabs., 39 refs.

  5. High Mobility Conjugated Polymers

    Science.gov (United States)

    2007-10-20

    blends with poly(3- hexylthiophene) (PHT) could be readily fabricated as uniform nanofibers by co- electrospinning their solutions with another solution...We have demonstrated that nanofibers of conjugated 10 - polymers and their blends could be conveniently fabricated by electrospinning . Furthermore, we...luminance o - - characteristics of an ITO/ PEDOT /TAPC k D r a Vol gt, V, (V) /BPQ-PPO/LiF/A! device are shown in Fig. 30. (A) Current density-voltage

  6. Dynamics of polymers

    International Nuclear Information System (INIS)

    Buchenau, U.

    1996-01-01

    Neutron scattering from amorphous polymers allows to switch from incoherent to coherent scattering in the same substance. The power of the tool for the study of the picosecond dynamics of disordered matter is illustrated for polybutadiene, polycarbonate and polystyrene. The results suggest a mixture of sound waves and localized modes, strongly interacting with each other, in the picosecond range. (author) 8 figs., tabs., 39 refs

  7. CLASSIFICATION OF BIODEGRADABLE POLYMERS

    Directory of Open Access Journals (Sweden)

    I. I. Karpunin

    2015-01-01

    Full Text Available The executed investigations have made it possible to ascertain that a morphological structure of starch granules mainly determine technological peculiarities of starch isolation from raw material, its modification and its later use. Morphological structure of starch granules primarily depends on type of plant starch-containing raw material which has been used for its isolation. Class of raw material exerts a strong impact on the shape and size of the granules. Linear “light” amylose chains and “heavy” amylopectin branch chains form a starch granule ultrastructure. X-ray research has proved that starch granules are characterized by presence of interlacing amorphous and crystalline regions. In this case polymer orientation using stretching of the obtained end product influences on its physical and mechanical  indices which are increasing due to polymer orientation. For the purpose of packaging orientation of polymer films can solve such important problems as significant improvement of operational properties, creation of  thermosetting film materials, improvement of qualitative indices of the recycled film.Results of the conducted research have proved the fact that it is necessary to make changes in technology in order to increase biological degradability of the recycled packaging made from polymers and improve physical and mechanical indices. In this regard film production technology presupposes usage of such substances as stark and others which are characterized by rather large presence of branch chains of molecules and interlacing amorphous and crystalline regions. Such approach makes it possible to obtain after-use package which is strong and quickly degradable by micro-organisms.

  8. Polymer engineering (I)

    International Nuclear Information System (INIS)

    Kim, Seong Cheol; Kim, Do Hyeon; Lee, Gi Yun

    1994-08-01

    This book deals with polymer engineering, which gives descriptions of addition polymerization, condensation polymerization, special polymerization, copolymerization, reaction of a high molecule, polymerization process, structure of a high molecule chain, molecular weight, crystal structure of a high molecule, melting and glass transition, viscoelasticity of a high molecule, rubber elasticity, transform and destroy of a high molecule, property of another matter, melting rheology of a high molecule, flowing in the tube and channel, pressing, injection molding, calendaring and spinning process.

  9. Absorbable and biodegradable polymers

    CERN Document Server

    Shalaby, Shalaby W

    2003-01-01

    INTRODUCTION NOTES: Absorbable/Biodegradable Polymers: Technology Evolution. DEVELOPMENT AND APPLICATIONOF NEW SYSTEMS: Segmented Copolyesters with Prolonged Strength Retention Profiles. Polyaxial Crystalline Fiber-Forming Copolyester. Polyethylene Glycol-Based Copolyesters. Cyanoacrylate-Based Systems as Tissue Adhesives. Chitosan-Based Systems. Hyaluronic Acid-Based Systems. DEVELOPMENTS IN PREPARATIVE, PROCESSING, AND EVALUATION METHODS: New Approaches to the Synthesis of Crystalline. Fiber-Forming Aliphatic Copolyesters. Advances in Morphological Development to Tailor the Performance of Me

  10. Conductive Polymer Composites

    OpenAIRE

    Pierini, Filippo

    2013-01-01

    In recent years, nanotechnologies have led to the production of materials with new and sometimes unexpected qualities through the manipulation of nanoscale components. This research aimed primarily to the study of the correlation between hierarchical structures of hybrid organic-inorganic materials such as conductive polymer composites (CPCs). Using a bottom-up methodology, we could synthesize a wide range of inorganic nanometric materials with a high degree of homogeneity and purity, ...

  11. Enhancement of Polymer Cytocompatibility by Nanostructuring of Polymer Surface

    Directory of Open Access Journals (Sweden)

    Petr Slepička

    2012-01-01

    Full Text Available Polymers with their advantageous physical, chemical, mechanical, and electrical properties and easy manufacturing are widely used in biology, tissue engineering, and medicine, for example, as prosthetic materials. In some cases the polymer usage may be impeded by low biocompatibility of common synthetic polymers. The biocompatibility can be improved by modification of polymer surface, for example, by plasma discharge, irradiation with ionizing radiation, and sometime subsequent grafting with suitable organic (e.g., amino-acids or inorganic (e.g., gold nanoparticles agents. In this way new chemically active structures are created on the polymer surface, and in some cases new surface relief is created. Recent advances in nanotechnology and in characterization of nanostructured objects open the way to development of new polymer-based materials with better bio-properties and higher application potential in biomedicine. Some of recent results obtained in the field are summarized and discussed in this paper.

  12. Simulated Associating Polymer Networks

    Science.gov (United States)

    Billen, Joris

    Telechelic associating polymer networks consist of polymer chains terminated by endgroups that have a different chemical composition than the polymer backbone. When dissolved in a solution, the endgroups cluster together to form aggregates. At low temperature, a strongly connected reversible network is formed and the system behaves like a gel. Telechelic networks are of interest since they are representative for biopolymer networks (e.g. F-actin) and are widely used in medical applications (e.g. hydrogels for tissue engineering, wound dressings) and consumer products (e.g. contact lenses, paint thickeners). In this thesis such systems are studied by means of a molecular dynamics/Monte Carlo simulation. At first, the system in rest is studied by means of graph theory. The changes in network topology upon cooling to the gel state, are characterized. Hereto an extensive study of the eigenvalue spectrum of the gel network is performed. As a result, an in-depth investigation of the eigenvalue spectra for spatial ER, scale-free, and small-world networks is carried out. Next, the gel under the application of a constant shear is studied, with a focus on shear banding and the changes in topology under shear. Finally, the relation between the gel transition and percolation is discussed.

  13. Polymer structure database and protein-polymer interactions

    Czech Academy of Sciences Publication Activity Database

    Hašek, Jindřich; Labský, Jiří; Skálová, Tereza; Kolenko, Petr; Dohnálek, Jan; Dušková, Jarmila; Štěpánková, Andrea; Koval, T.

    -, č. 1 (2011), s. 475-480 ISSN 1869-1315. [European Powder Diffraction Conference EPDIC 12 /12./. Darmstadt, 27.08.2010-30.08.2010] R&D Projects: GA ČR GA305/07/1073; GA AV ČR IAA500500701 Institutional research plan: CEZ:AV0Z40500505 Keywords : hydrophilic polymers * crystalline polymers * adhesion of polymers Subject RIV: CD - Macromolecular Chemistry http://www.oldenbourg-link.com/doi/pdf/10.1524/zkpr.2011.0072

  14. Polymer microvalve with pre-stressed membranes for tunable flow–pressure characteristics

    DEFF Research Database (Denmark)

    Snakenborg, Detlef; Klank, Henning; Kutter, Jörg Peter

    2011-01-01

    A novel, inexpensive, polymer-based valve approach is presented that offers the combination of a check valve’s rectifying properties with the possibility to actively control the flow rate in the forward (open) direction. An elastic membrane with an incision is clamped between two rigid polymer pl...

  15. Experimental investigation for graphene and carbon fibre in polymer-based matrix for structural applications

    Directory of Open Access Journals (Sweden)

    Shankar A. Hallad

    2017-06-01

    Full Text Available The present paper investigates the behaviour of a polymer matrix beam reinforced with graphene and carbon fibres at nano and micro level reinforcements, respectively, to study mainly the strength aspects for structural applications. However an attempt has also been made to use a combination of both micro and nano level fillers in both individual and combined forms as reinforcements. The addition of graphene and carbon fibres in the control beams was varied from 0.1 to 0.4% percent by weight of polymer matrix. Dispersion of graphene was carried out using ultrasonic energy. Composite beams were tested under flexural in order to evaluate their mechanical property such as load-deflection criteria. These results were then compared with those obtained from plain polymer beams. The present work also investigates the optimum percentage of graphene and carbon fibres as individual and combination fillers that gave the best results in terms of enhanced mechanical properties and economical aspects as well. Scanning electron microscopy and energy dispersion X-ray spectroscopy was conducted to examine the interfacial surface adhesion between the fillers and the polymer matrix. Reinforcement of polymer beams with graphene alone by weight of the polymer matrix showed enhanced results when compared to carbon fibres alone while the use of combined nano and micro reinforcements showed performance lying in between nano and micro fillers in the polymer. Flexural strength is enhanced by 35% compared to plain control beams when graphene was used as reinforcement fillers in the polymer matrix.

  16. Polymers for IUdR radiosensitization of experimental glioblastoma

    International Nuclear Information System (INIS)

    Williams, Jeffery A.; Xuan Yuan; Brem, Henry

    1997-01-01

    R (fluorescein isothiocyanate (FITC) labeled anti-IUdR antibody) and for DNA (propidium iodide). Toxicity: Groups of at ≥ 5 non-tumor bearing mice had i.c. implantation of empty (control) or experimental (50% IUdR) polymers (Day 0) alone or combined with cranial external beam irradiation (5 Gy x 2 on days 7 and 8 vs. 2 Gy BID on days 7-10) given via a calibrated 137-Cs irradiator. For in vivo radiosensitization, groups of ≥ 8 mice had sequential i.c. inoculation (2 x 10 5 cells on day 0), craniectomy and implantation of empty (control) or experimental (50% IUdR) polymers, and irradiation. To explore the effect of the timing and escalation of the radiation dose, the interval from implantation of polymers until radiation were: Expt 1:) 5 days (5 Gy on days 7 and 8 (10 Gy total)) vs. Expt 2:) 4 or 7 days (2 Gy BID x 4 on days 7-10 (16 Gy total)). Survival was recorded. Results: In vitro: The polymer provides controlled release of IUdR. After 4 days the cumulative percentages released were 43.7 ± 0.1, 70.0 ± 0.2, and 90.2 ± 0.2 (p 10 ) was -2.02 ± 0.02 or -3.68 ± 0.11 (p < 0.001), respectively. In vivo: Release: The measured activity (cpm) of i.c. 125-IUdR polymers showed protracted decrease vs. time. The proportions of implanted activity were 0.86 ± 0.08, 0.77 ± 0.10, 0.30 ± 0.03 and 0.07 ± 0.01 measured 23, 43, 120 and 311 hours, respectively, after implantation. IUdR polymers caused high tumor labeling. When measured 4 vs. 8 days after IUdR polymer implantation, the mean percentages (± SEM) of labeled tumor cells 0 (coplanar with polymer), 1 and 2 mm distant were striking: 67 ± 11, 42 ± 4, and 32 ± 9 vs. 54 ± 8, 48 ± 5 and 12 ± 4 (p = NS day 4 vs. 8), respectively. Toxicity: No deaths were recorded 80 days after polymer vs. combined polymer and radiation treatments. Radiosensitization: Expt 1: The median survival (d) was 15 for empty polymers alone vs. 16 (p = NS) or 17 (p = NS) for IUdR polymers alone or no treatment, respectively. Survival after empty vs

  17. Writing on polymer chains.

    Science.gov (United States)

    Lutz, Jean-François

    2013-11-19

    Synthetic polymer materials are currently limited by their inability to store information in their chains, unlike some well-characterized biopolymers. Nucleic acids store and transmit genetic information, and amino acids encode the complex tridimensional structures and functions within proteins. To confer similar properties on synthetic materials, researchers must develop"writing" mechanisms, facile chemical pathways that allow control over the primary structure of synthetic polymer chains. The most obvious way to control the primary structure is to connect monomer units one-by-one in a given order using iterative chemistry. Although such synthesis strategies are commonly used to produce peptides and nucleic acids, they produce limited yields and are much slower than natural polymerization mechanisms. An alternative strategy would be to use multiblock copolymers with blocks that have specified sequences. In this case, however, the basic storage element is not a single molecular unit, but a longer block composed of several repeating units. However, the synthesis of multiblock copolymers is long and tedious. Therefore, researchers will need to develop other strategies for writing information onto polymer chains. In this Account, I describe our recent progress in the development of sequence controlled polymerization methods. Although our research focuses on different strategies, we have emphasized sequence-regulation in chain-growth polymerization processes. Chain-growth polymerizations, particularly radical polymerization, are very convenient methods for synthesizing polymers. However, in most cases, such approaches do not lead to controlled monomer sequences. During the last five years, we have shown that controlled/living chain-growth polymerization mechanisms offer interesting advantages for sequence regulation. In such mechanisms, the chains form gradually over time, and therefore the primary structure can be tuned by using time-controlled monomer additions. For

  18. Synthetic approaches to uniform polymers.

    Science.gov (United States)

    Ali, Monzur; Brocchini, Steve

    2006-12-30

    Uniform polymers are characterised by a narrow molecular weight distribution (MWD). Uniformity is also defined by chemical structure in respect of (1) monomer orientation, sequence and stereo-regularity, (2) polymer shape and morphology and (3) chemical functionality. The function of natural polymers such as polypeptides and polynucleotides is related to their conformational structure (e.g. folded tertiary structure). This is only possible because of their high degree of uniformity. While completely uniform synthetic polymers are rare, polymers with broad structure and MWD are widely used in medicine and the biomedical sciences. They are integral components in final dosage forms, drug delivery systems (DDS) and in implantable devices. Increasingly uniform polymers are being used to develop more complex medicines (e.g. delivery of biopharmaceuticals, enhanced formulations or DDS's for existing actives). In addition to the function imparted by any new polymer it will be required to meet stringent specifications in terms of cost containment, scalability, biocompatibility and performance. Synthetic polymers with therapeutic activity are also being developed to exploit their polyvalent properties, which is not possible with low molecular weight molecules. There is need to utilise uniform polymers for applications where the polymer may interact with the systemic circulation, tissues or cellular environment. There are also potential applications (e.g. stimuli responsive coatings) where uniform polymers may be used for their more defined property profile. While it is not yet practical to prepare synthetic polymers to the same high degree of uniformity as proteins, nature also effectively utilises many polymers with lower degrees of uniformity (e.g. polysaccharides, poly(amino acids), polyhydroxyalkanoates). In recent years it has become possible to prepare with practical experimental protocols sufficient quantities of polymers that display many aspects of uniformity. This

  19. Winning Combinations

    DEFF Research Database (Denmark)

    Criscuolo, Paola; Laursen, Keld; Reichstein, Toke

    2018-01-01

    Searching for the most rewarding sources of innovative ideas remains a key challenge in management of technological innovation. Yet, little is known about which combinations of internal and external knowledge sources are triggers for innovation. Extending theories about searching for innovation, we...... examine the effectiveness of different combinations of knowledge sources for achieving innovative performance. We suggest that combinations involving integrative search strategies – combining internal and external knowledge – are the most likely to generate product and process innovation. In this context...

  20. Claisen thermally rearranged (CTR) polymers

    Science.gov (United States)

    Tena, Alberto; Rangou, Sofia; Shishatskiy, Sergey; Filiz, Volkan; Abetz, Volker

    2016-01-01

    Thermally rearranged (TR) polymers, which are considered the next-generation of membrane materials because of their excellent transport properties and high thermal and chemical stability, are proven to have significant drawbacks because of the high temperature required for the rearrangement and low degree of conversion during this process. We demonstrate that using a [3,3]-sigmatropic rearrangement, the temperature required for the rearrangement of a solid glassy polymer was reduced by 200°C. Conversions of functionalized polyimide to polybenzoxazole of more than 97% were achieved. These highly mechanically stable polymers were almost five times more permeable and had more than two times higher degrees of conversion than the reference polymer treated under the same conditions. Properties of these second-generation TR polymers provide the possibility of preparing efficient polymer membranes in a form of, for example, thin-film composite membranes for various gas and liquid membrane separation applications. PMID:27482538

  1. Nanoporous materials modified with biodegradable polymers as models for drug delivery applications

    DEFF Research Database (Denmark)

    Gruber, Mathias F; Schulte, Lars; Ndoni, Sokol

    2013-01-01

    Polymers play a central role in the development of carriers for diagnostic and therapeutic agents. Especially the use of either degradable polymers or porous materials to encapsulate drug compounds in order to obtain steady drug release profiles has received much attention. We present here a proof...... of principle for a system combining these two encapsulation methods and consisting of a nanoporous polymer (NP) with the pores filled with a degradable polymer mixed with a drug model. Rhodamine 6G (R6G) mixed with Poly(l-Lactic Acid) (PLLA) were confined within the 14nm pores of a NP with gyroid morphology...

  2. Plasmon assisted synthesis of highly fluorescing silver quantum cluster / polymer composites for biochemical sensing

    DEFF Research Database (Denmark)

    Bernard, S.; Kutter, J.P.; Mogensen, Klaus Bo

    2014-01-01

    Plasmonics is combined with polymer synthesis for rapid fabrication of highly fluorescing silver quantum cluster / polymer composites inside microfluidic channels. UV-light assisted synthesis of polymers has been investigated by a number of groups previously [1], however, plasmon assisted synthesis...... has not been presented before. This should allow highly localized fabrication of porous polymers that are defined by the location of the nanoplasmonic metal film. Silver quantum clusters (AgQCs) consisting of 2-10 atoms can be highly fluorescing in the visible wavelength range and possess a much...

  3. Plasmon assisted synthesis of highly fluorescing silver quantum cluster/polymer composites for biochemical sensing

    DEFF Research Database (Denmark)

    Bernard, S.; Kutter, J. P.; Mogensen, K. B.

    2014-01-01

    Plasmonics is combined with polymer synthesis for rapid fabrication of highly fluorescing silver quantum cluster/polymer composites inside microfluidic channels. UV-light assisted synthesis of polymers has been investigated by a number of groups previously [1], however, plasmon assisted synthesis...... has not been presented before. This should allow highly localized fabrication of porous polymers that are defined by the location of the nanoplasmonic metal film. Silver quantum clusters (AgQCs) consisting of 2-10 atoms can be highly fluorescing in the visible wavelength range and possess a greater...

  4. Application of Composite Polymer Electrolytes

    National Research Council Canada - National Science Library

    Scrosati, Bruno

    2001-01-01

    ...)PEO-based composite polymer electrolytes, by a series of specifically addressed electrochemical tests which included the determination of the conductivity and of the lithium transference number...

  5. Multifunctional Polymer/Inorganic Nanocomposites

    National Research Council Canada - National Science Library

    Manias, E

    2003-01-01

    ... in multifunctional nanocomposite materials. Understanding the structure/property relations in polymer/clay nanocomposites is of great importance in designing materials with desired sets of properties...

  6. Wear of polymers and composites

    CERN Document Server

    Abdelbary, Ahmed

    2015-01-01

    In the field of tribology, the wear behaviour of polymers and composite materials is considered a highly non-linear phenomenon. Wear of Polymers and Composites introduces fundamentals of polymers and composites tribology. The book suggests a new approach to explore the effect of applied load and surface defects on the fatigue wear behaviour of polymers, using a new tribometer and thorough experiments. It discusses effects of surface cracks, under different static and cyclic loading parameters on wear, and presents an intelligent algorithm, in the form of a neural network, to map the relations

  7. Phenomenology of polymer solution dynamics

    National Research Council Canada - National Science Library

    Phillies, George D. J

    2011-01-01

    ... solutions, not dilute solutions or polymer melts. From centrifugation and solvent dynamics to viscosity and diffusion, experimental measurements and their quantitative representations are the core of the discussion...

  8. Biomimetic Polymers with Antimicrobial Activity

    National Research Council Canada - National Science Library

    Tew, Gregory

    2003-01-01

    .... Our intention was to use this understanding to develop polymers that are more stable and inexpensive to produce than natural proteins, but nevertheless mimic their important biological properties...

  9. Sustainable polymers from renewable resources.

    Science.gov (United States)

    Zhu, Yunqing; Romain, Charles; Williams, Charlotte K

    2016-12-14

    Renewable resources are used increasingly in the production of polymers. In particular, monomers such as carbon dioxide, terpenes, vegetable oils and carbohydrates can be used as feedstocks for the manufacture of a variety of sustainable materials and products, including elastomers, plastics, hydrogels, flexible electronics, resins, engineering polymers and composites. Efficient catalysis is required to produce monomers, to facilitate selective polymerizations and to enable recycling or upcycling of waste materials. There are opportunities to use such sustainable polymers in both high-value areas and in basic applications such as packaging. Life-cycle assessment can be used to quantify the environmental benefits of sustainable polymers.

  10. Small angle scattering and polymers

    Energy Technology Data Exchange (ETDEWEB)

    Cotton, J.P. [Laboratoire Leon Brillouin (LLB) - Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1996-12-31

    The determination of polymer structure is a problem of interest for both statistical physics and industrial applications. The average polymer structure is defined. Then, it is shown why small angle scattering, associated with isotopic substitution, is very well suited to the measurement of the chain conformation. The corresponding example is the old, but pedagogic, measurement of the chain form factor in the polymer melt. The powerful contrast variation method is illustrated by a recent determination of the concentration profile of a polymer interface. (author) 12 figs., 48 refs.

  11. Polymer Processing and Characterization Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The purpose is to process and evaluate polymers for use in nonlinear optical, conductive and structural Air Force applications. Primary capabilities are extrusion of...

  12. POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

    DEFF Research Database (Denmark)

    2001-01-01

    A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various thermopl......A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various...... thermoplastic polymers for high temperature polymer electrolyte fuel cells have also been developed. Miscible blends are used for solution casting of polymer membranes (solid electrolytes). High conductivity and enhanced mechanical strength were obtained for the blend polymer solid electrolytes...... electrolyte membrane by hot-press. The fuel cell can operate at temperatures up to at least 200 °C with hydrogen-rich fuel containing high ratios of carbon monoxide such as 3 vol% carbon monoxide or more, compared to the carbon monoxide tolerance of 10-20 ppm level for Nafion$m(3)-based polymer electrolyte...

  13. Discovery of Antibiotics-derived Polymers for Gene Delivery using Combinatorial Synthesis and Cheminformatics Modeling

    Science.gov (United States)

    Potta, Thrimoorthy; Zhen, Zhuo; Grandhi, Taraka Sai Pavan; Christensen, Matthew D.; Ramos, James; Breneman, Curt M.; Rege, Kaushal

    2014-01-01

    We describe the combinatorial synthesis and cheminformatics modeling of aminoglycoside antibiotics-derived polymers for transgene delivery and expression. Fifty-six polymers were synthesized by polymerizing aminoglycosides with diglycidyl ether cross-linkers. Parallel screening resulted in identification of several lead polymers that resulted in high transgene expression levels in cells. The role of polymer physicochemical properties in determining efficacy of transgene expression was investigated using Quantitative Structure-Activity Relationship (QSAR) cheminformatics models based on Support Vector Regression (SVR) and ‘building block’ polymer structures. The QSAR model exhibited high predictive ability, and investigation of descriptors in the model, using molecular visualization and correlation plots, indicated that physicochemical attributes related to both, aminoglycosides and diglycidyl ethers facilitated transgene expression. This work synergistically combines combinatorial synthesis and parallel screening with cheminformatics-based QSAR models for discovery and physicochemical elucidation of effective antibiotics-derived polymers for transgene delivery in medicine and biotechnology. PMID:24331709

  14. Interfacial characteristics of binary polymer blend films spread at the air-water interface.

    Science.gov (United States)

    Kawaguchi, Masami

    2017-09-01

    The interfacial characteristics of binary polymer blend films spread at the air-water interface are reviewed, focusing on their surface pressures, interfacial structures, and dilational moduli as a function of the miscibility. Miscible polymer blend films show thermodynamic, structural, and dynamic properties which are a combination of those from both components in the polymer blend present at the air-water interface. No preferential adsorption is observed and the behavior does not depend on the surface concentration regime. In contrast, for immiscible polymer blend films, preferential adsorption of one polymer phase occurs at the air-water interface and the interfacial characteristics in the semi-dilute and concentrated regimes are strongly controlled by one of the components of the adsorbed polymer. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Discovery of antibiotics-derived polymers for gene delivery using combinatorial synthesis and cheminformatics modeling.

    Science.gov (United States)

    Potta, Thrimoorthy; Zhen, Zhuo; Grandhi, Taraka Sai Pavan; Christensen, Matthew D; Ramos, James; Breneman, Curt M; Rege, Kaushal

    2014-02-01

    We describe the combinatorial synthesis and cheminformatics modeling of aminoglycoside antibiotics-derived polymers for transgene delivery and expression. Fifty-six polymers were synthesized by polymerizing aminoglycosides with diglycidyl ether cross-linkers. Parallel screening resulted in identification of several lead polymers that resulted in high transgene expression levels in cells. The role of polymer physicochemical properties in determining efficacy of transgene expression was investigated using Quantitative Structure-Activity Relationship (QSAR) cheminformatics models based on Support Vector Regression (SVR) and 'building block' polymer structures. The QSAR model exhibited high predictive ability, and investigation of descriptors in the model, using molecular visualization and correlation plots, indicated that physicochemical attributes related to both, aminoglycosides and diglycidyl ethers facilitated transgene expression. This work synergistically combines combinatorial synthesis and parallel screening with cheminformatics-based QSAR models for discovery and physicochemical elucidation of effective antibiotics-derived polymers for transgene delivery in medicine and biotechnology. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. An entropy spring model for the Young's modulus change of biodegradable polymers during biodegradation.

    Science.gov (United States)

    Wang, Ying; Han, Xiaoxiao; Pan, Jingzhe; Sinka, Csaba

    2010-01-01

    This paper presents a model for the change in Young's modulus of biodegradable polymers due to hydrolysis cleavage of the polymer chains. The model is based on the entropy spring theory for amorphous polymers. It is assumed that isolated polymer chain cleavage and very short polymer chains do not affect the entropy change in a linear biodegradable polymer during its deformation. It is then possible to relate the Young's modulus to the average molecular weight in a computer simulated hydrolysis process of polymer chain sessions. The experimental data obtained by Tsuji [Tsuji, H., 2002. Autocatalytic hydrolysis of amorphous-made polylactides: Effects of L-lactide content, tacticity, and enantiomeric polymer blending. Polymers 43, 1789-1796] for poly(L-lactic acid) and poly(D-lactic acid) are examined using the model. It is shown that the model can provide a common thread through Tsuji's experimental data. A further numerical case study demonstrates that the Young's modulus obtained using very thin samples, such as those obtained by Tsuji, cannot be directly used to calculate the load carried by a device made of the same polymer but of various thicknesses. This is because the Young's modulus varies significantly in a biodegradable device due to the heterogeneous nature of the hydrolysis reaction. The governing equations for biodegradation and the relation between the Young's modulus and average molecular weight can be combined to calculate the load transfer from a degrading device to a healing bone.

  17. Clickable antifouling polymer brushes for polymer pen lithography

    Czech Academy of Sciences Publication Activity Database

    Bog, U.; de los Santos Pereira, Andres; Mueller, S. L.; Havenridge, S.; Parrillo, Viviana; Bruns, M.; Holmes, A. E.; Rodriguez-Emmenegger, C.; Fuchs, H.; Hirtz, M.

    2017-01-01

    Roč. 9, č. 13 (2017), s. 12109-12117 ISSN 1944-8244 R&D Projects: GA ČR(CZ) GJ15-09368Y Institutional support: RVO:61389013 Keywords : antifouling * biofunctional interfaces * polymer brushes Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 7.504, year: 2016

  18. Enhancement of Polymer Cytocompatibility by Nanostructuring of Polymer Surface

    Czech Academy of Sciences Publication Activity Database

    Slepička, P.; Kasálková-Slepičková, N.; Bačáková, Lucie; Kolská, Z.; Švorčík, V.

    2012-01-01

    Roč. 2012, č. 2012 (2012), ID527403 ISSN 1687-4110 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:67985823 Keywords : polymer cytocompatibility * polymer surface * nanotechnology Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.547, year: 2012

  19. Influence of polymer architectures on diffusion in unentangled polymer melts.

    Science.gov (United States)

    Chremos, Alexandros; Jeong, Cheol; Douglas, Jack F

    2017-08-30

    Recent simulations have indicated that the thermodynamic properties and the glassy dynamics of polymer melts are strongly influenced by the average molecular shape, as quantified by the radius of gyration tensor of the polymer molecules, and that the average molecular shape can be tuned by varying the molecular topology (e.g., ring, star, linear chain, etc.). In the present work, we investigate if the molecular shape is similarly a predominant factor in understanding the polymer center of mass diffusion D in the melt, as already established for polymer solutions. We find that all our D data for unentangled polymer melts having a range of topologies can be reasonably described as a power law of the polymer hydrodynamic radius, R h . In particular, this scaling is similar to the scaling of D for a tracer sphere having a radius on the order of the chain radius of gyration, R g . We conclude that the chain topology influences the molecular dynamics in as much as the polymer topology influences the average molecular shape. Experimental evidence seems to suggest that this situation is also true for entangled polymer melts.

  20. Conductivity behaviour of polymer gel electrolytes: Role of polymer

    Indian Academy of Sciences (India)

    Unknown

    with salicylic acid it has recently been found (Sekhon et al 2003) that the change in conductivity with polymer addition also depends upon the donor numbers of the solvent used. Solvent with high and low donor number show different conductivity behaviour in polymer gel electrolytes. On the basis of different experimental ...

  1. Polymer Crowding in Confined Polymer-Nanoparticle Mixtures

    Science.gov (United States)

    Davis, Wyatt J.; Denton, Alan R.

    Crowding can influence the conformations and thus functionality of macromolecules in quasi-two-dimensional environments, such as DNA or proteins confined to a cell membrane. We explore such crowding within a model of polymers as penetrable ellipses, whose shapes are governed by the statistics of a 2D random walk. The principal radii of the polymers fluctuate according to probability distributions of the eigenvalues of the gyration tensor. Within this coarse-grained model, we perform Monte Carlo simulations of mixtures of polymers and hard nanodisks, including trial changes in polymer conformation (shape and orientation). Penetration of polymers by nanodisks is incorporated with a free energy cost predicted by polymer field theory. Over ranges of size ratio and nanodisk density, we analyze the influence of crowding on polymer shape by computing eigenvalue distributions, mean radius of gyration, and mean asphericity of the polymer. We compare results with predictions of free-volume theory and with corresponding results in three dimensions. Our approach may help to interpret recent (and motivate future) experimental studies of biopolymers interacting with cell membranes, with relevance for drug delivery and gene therapy. This work was supported by the National Science Foundation under Grant No. DMR-1106331.

  2. Radiation Synthesis of Superabsorbent Polymers Based on Natural Polymers

    International Nuclear Information System (INIS)

    Sen, Murat; Hayrabolulu, Hande

    2010-01-01

    The objectives of proposed research contract were first synthesize superabsorbent polymers based on natural polymers to be used as disposable diapers and soil conditioning materials in agriculture, horticulture and other super adsorbent using industries. We have planned to use the natural polymers; locust beam gum, tara gum, guar gum and sodium alginate on the preparation of natural superabsorbent polymers(SAP). The aqueous solution of natural polymers and their blends with trace amount of monomer and cross-linking agents will be irradiated in paste like conditions by gamma rays for the preparation of cross-linked superabsorbent systems. The water absorption and deswellling capacity of prepared super adsorbents and retention capacity, absorbency under load, suction power, swelling pressure and pet-rewet properties will be determined. Use of these materials instead of synthetic super absorbents will be examined by comparing the performance of finished products. The experimental studies achieved in the second year of project mainly on the effect of radiation on the chemistry of sodium alginate polymers in different irradiation conditions and structure-property relationship particularly with respect to radiation induced changes on the molecular weight of natural polymers and preliminary studies on the synthesis of natural-synthetic hydride super adsorbent polymers were given in details

  3. Hybrid Polymer-Network Hydrogels with Tunable Mechanical Response

    Directory of Open Access Journals (Sweden)

    Sebastian Czarnecki

    2016-03-01

    Full Text Available Hybrid polymer-network gels built by both physical and covalent polymer crosslinking combine the advantages of both these crosslinking types: they exhibit high mechanical strength along with excellent fracture toughness and extensibility. If these materials are extensively deformed, their physical crosslinks can break such that strain energy is dissipated and irreversible fracturing is restricted to high strain only. This mechanism of energy dissipation is determined by the kinetics and thermodynamics of the physical crosslinking contribution. In this paper, we present a poly(ethylene glycol (PEG based material toolkit to control these contributions in a rational and custom fashion. We form well-defined covalent polymer-network gels with regularly distributed additional supramolecular mechanical fuse links, whose strength of connectivity can be tuned without affecting the primary polymer-network composition. This is possible because the supramolecular fuse links are based on terpyridine–metal complexation, such that the mere choice of the fuse-linking metal ion adjusts their kinetics and thermodynamics of complexation–decomplexation, which directly affects the mechanical properties of the hybrid gels. We use oscillatory shear rheology to demonstrate this rational control and enhancement of the mechanical properties of the hybrid gels. In addition, static light scattering reveals their highly regular and well-defined polymer-network structures. As a result of both, the present approach provides an easy and reliable concept for preparing hybrid polymer-network gels with rationally designed properties.

  4. Thermodynamic phase behavior of API/polymer solid dispersions.

    Science.gov (United States)

    Prudic, Anke; Ji, Yuanhui; Sadowski, Gabriele

    2014-07-07

    To improve the bioavailability of poorly soluble active pharmaceutical ingredients (APIs), these materials are often integrated into a polymer matrix that acts as a carrier. The resulting mixture is called a solid dispersion. In this work, the phase behaviors of solid dispersions were investigated as a function of the API as well as of the type and molecular weight of the carrier polymer. Specifically, the solubility of artemisinin and indomethacin was measured in different poly(ethylene glycol)s (PEG 400, PEG 6000, and PEG 35000). The measured solubility data and the solubility of sulfonamides in poly(vinylpyrrolidone) (PVP) K10 and PEG 35000 were modeled using the perturbed-chain statistical associating fluid theory (PC-SAFT). The results show that PC-SAFT predictions are in a good accordance with the experimental data, and PC-SAFT can be used to predict the whole phase diagram of an API/polymer solid dispersion as a function of the kind of API and polymer and of the polymer's molecular weight. This remarkably simplifies the screening process for suitable API/polymer combinations.

  5. Simultaneous Thermal and Gamma Radiation Aging of Electrical Cable Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Fifield, Leonard S.

    2018-04-11

    The polymers used for insulation in nuclear power plant electrical cables are susceptible to aging during long term operation. Elevated temperature is the primary contributor to changes in polymer structure that result loss of mechanical and electrical properties, but gamma radiation is also a significant source of degradation for polymers used within relevant plant locations. Despite many years of polymer degradation research, the combined effects of simultaneous exposure to thermal and radiation stress are not well understood. As nuclear operators contemplate and prepare for extended operations beyond initial license periods, a predictive understanding of exposure-based cable material degradation is becoming an increasingly important input to safety, licensing, operations and economic decisions. We are focusing on carefully-controlled simultaneous thermal and gamma radiation accelerating aging and characterization of the most common nuclear cable polymers to understand the relative contributions of temperature, time, dose and dose rate to changes in cable polymer material structure and properties. Improved understanding of cable performance in long term operation will help support continued sustainable nuclear power generation.

  6. Hybrid protein-synthetic polymer nanoparticles for drug delivery.

    Science.gov (United States)

    Koseva, Neli S; Rydz, Joanna; Stoyanova, Ekaterina V; Mitova, Violeta A

    2015-01-01

    Among the most common nanoparticulate systems, the polymeric nanocarriers have a number of key benefits, which give a great choice of delivery platforms. Nevertheless, polymeric nanoparticles possess some limitations that include use of toxic solvents in the production process, polymer degradation, drug leakage outside the diseased tissue, and polymer cytotoxicity. The combination of polymers of biological and synthetic origin is an appealing modern strategy for the production of novel nanocarriers with unprecedented properties. Proteins' interface can play an important role in determining bioactivity and toxicity and gives perspective for future development of the polymer-based nanoparticles. The design of hybrid constructs composed of synthetic polymer and biological molecules such as proteins can be considered as a straightforward tool to integrate a broad spectrum of properties and biofunctions into a single device. This review discusses hybrid protein-synthetic polymer nanoparticles with different structures and levels in complexity and functionality, in view of their applications as drug delivery systems. © 2015 Elsevier Inc. All rights reserved.

  7. Structural characterization of semicrystalline polymer morphologies by imaging-SANS

    International Nuclear Information System (INIS)

    Radulescu, A; Fetters, L J; Richter, D

    2012-01-01

    Control and optimization of polymer properties require the global knowledge of the constitutive microstructures of polymer morphologies in various conditions. The microstructural features can be typically explored over a wide length scale by combining pinhole-, focusing- and ultra-small-angle neutron scattering (SANS) techniques. Though it proved to be a successful approach, this involves major efforts related to the use of various scattering instruments and large amount of samples and the need to ensure the same crystallization kinetics for the samples investigated at various facilities, in different sample cell geometries and at different time intervals. With the installation and commissioning of the MgF 2 neutron lenses at the KWS-2 SANS diffractometer installed at the Heinz Maier-Leibnitz neutron source (FRMII reactor) in Garching, a wide Q-range, between 10 −4 Å −1 and 0.5Å −1 , can be covered at a single instrument. This enables investigation of polymer microstructures over a length scale from lnm up to 1μm, while the overall polymer morphology can be further examined up to 100μm by optical microscopy (including crossed polarizers). The study of different semi-crystalline polypropylene-based polymers in solution is discussed and the new imaging-SANS approach allowing for an unambiguous and complete structural characterization of polymer morphologies is presented.

  8. Paradoxes of thermodynamics of aqua-vapor-polymer interface equilibrium

    Science.gov (United States)

    Davankov, V. A.; Pastukhov, A. V.

    2011-05-01

    Schroeder's paradox is the different equilibrium degree of swelling for a hydrophilic polymer in saturated aqueous vapor and in liquid water; it is experimentally verified by the registration of increasing volume of spherical polymer samples upon the processes of vapor and liquid water sorption. Specimens of three main classes of hydrophilic cross-linked polymers were tested. These had gel, hypercrosslinked, and macroporous structures that differed by the scale of the Schroeder effect. A similar effect is typical also for hydrophobic polymers upon swelling in liquid organic solvents and their saturated vapor. The paradox is explained by the lower activity of a sorbate in a saturated vapor compared to its activity in a liquid phase. The ability of many samples of cross-linked polymers with different degrees of saturation with a sorbate to be at equilibrium with the saturated vapor of a sorbate is explained by the differences in the inner structure of these samples, i.e., by differing in the swelling combinations and the intensity of the interchain interactions in a polymer network.

  9. Development of Silicate Polymers

    DEFF Research Database (Denmark)

    Søgaard, Erik Gydesen; Simonsen, Morten Enggrob

    an inorganic binder is developed based on fumed silica and potassium hydroxide. The optimal composition of the binder system was determined using compressive strength test. The investigation showed that the strength of the inorganic binder was strongly related to the content of potassium hydroxide...... hydroxide in acid and increase pH to saturation of the metal hydroxide. It is assumed that the syntheses of the inorganic polymer are carried out through polymerisation of oligomers (dimer, trimer) which provide the actual unit structures of the three dimensional macromolecular structure. In this work...

  10. Polymer solidification national program

    International Nuclear Information System (INIS)

    Kalb, P.D.; Colombo, P.

    1993-04-01

    Brookhaven National Laboratory (BNL) has developed several new and innovative polymer processes for the solidification of low-level radioactive, hazardous and mixed wastes streams. Polyethylene and modified sulfur cement solidification technologies have undergone steady, gradual development at BNL over the past nine years. During this time they have progressed through each of the stages necessary for logical technology maturation: from process conception, parameter optimization, waste form testing, evaluation of long-term durability, economic analysis, and scale-up feasibility. This technology development represents a significant investment which can potentially provide DOE with both short- and long-term savings

  11. Electron transporting polymers for light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiao-Chang; Giles, M.; Holmes, A.B. [Univ. of Cambridge (United Kingdom)] [and others

    1995-12-01

    New oxadiazole-derived side chain polymers have been prepared by radical induced polymerization of the methacrylate precursors. The synthesis and characterization of the polymers as well as their application in enhancing emission in polymer LEDs will be reported.

  12. Combined nanoimprint and photolithography of integrated polymer optics

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Schøler, Mikkel; Gersborg-Hansen, Morten

    2007-01-01

    are defined in SU-8 resist, doped with Rhodamine 6G laser dye, shaped as planar slab waveguides on a Fused Silica buffer substrate, and with a lst-order DFB surface corrugation forming the laser resonator. When optically pumped at 532 nm, lasing is obtained in the wavelength range 560 nm -600 nm, determined...

  13. HPMA-based polymer conjugates with drug combination

    Czech Academy of Sciences Publication Activity Database

    Krakovičová, Hana; Etrych, Tomáš; Ulbrich, Karel

    2009-01-01

    Roč. 37, 3-4 (2009), s. 405-412 ISSN 0928-0987 R&D Projects: GA AV ČR KAN200200651; GA AV ČR IAAX00500803; GA AV ČR IAA400500806 Institutional research plan: CEZ:AV0Z40500505 Keywords : HPMA copolymers * drug carriers * doxorubicin Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.608, year: 2009

  14. Hybrid Photonic Integration on a Polymer Platform

    Directory of Open Access Journals (Sweden)

    Ziyang Zhang

    2015-09-01

    Full Text Available To fulfill the functionality demands from the fast developing optical networks, a hybrid integration approach allows for combining the advantages of various material platforms. We have established a polymer-based hybrid integration platform (polyboard, which provides flexible optical input/ouptut interfaces (I/Os that allow robust coupling of indium phosphide (InP-based active components, passive insertion of thin-film-based optical elements, and on-chip attachment of optical fibers. This work reviews the recent progress of our polyboard platform. On the fundamental level, multi-core waveguides and polymer/silicon nitride heterogeneous waveguides have been fabricated, broadening device design possibilities and enabling 3D photonic integration. Furthermore, 40-channel optical line terminals and compact, bi-directional optical network units have been developed as highly functional, low-cost devices for the wavelength division multiplexed passive optical network. On a larger scale, thermo-optic elements, thin-film elements and an InP gain chip have been integrated on the polyboard to realize a colorless, dual-polarization optical 90° hybrid as the frontend of a coherent receiver. For high-end applications, a wavelength tunable 100Gbaud transmitter module has been demonstrated, manifesting the joint contribution from the polyboard technology, high speed polymer electro-optic modulator, InP driver electronics and ceramic electronic interconnects.

  15. The structural diversity of artificial genetic polymers.

    Science.gov (United States)

    Anosova, Irina; Kowal, Ewa A; Dunn, Matthew R; Chaput, John C; Van Horn, Wade D; Egli, Martin

    2016-02-18

    Synthetic genetics is a subdiscipline of synthetic biology that aims to develop artificial genetic polymers (also referred to as xeno-nucleic acids or XNAs) that can replicate in vitro and eventually in model cellular organisms. This field of science combines organic chemistry with polymerase engineering to create alternative forms of DNA that can store genetic information and evolve in response to external stimuli. Practitioners of synthetic genetics postulate that XNA could be used to safeguard synthetic biology organisms by storing genetic information in orthogonal chromosomes. XNA polymers are also under active investigation as a source of nuclease resistant affinity reagents (aptamers) and catalysts (xenozymes) with practical applications in disease diagnosis and treatment. In this review, we provide a structural perspective on known antiparallel duplex structures in which at least one strand of the Watson-Crick duplex is composed entirely of XNA. Currently, only a handful of XNA structures have been archived in the Protein Data Bank as compared to the more than 100 000 structures that are now available. Given the growing interest in xenobiology projects, we chose to compare the structural features of XNA polymers and discuss their potential to access new regions of nucleic acid fold space. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  16. Polymer fiber detectors for photoacoustic imaging

    Science.gov (United States)

    Grün, Hubert; Berer, Thomas; Pühringer, Karoline; Nuster, Robert; Paltauf, Günther; Burgholzer, Peter

    2010-02-01

    Photoacoustic imaging is a novel imaging method for medical and biological applications, combining the advantages of Diffuse Optical Imaging (high contrast) and Ultrasonic Imaging (high spatial resolution). A short laser pulse hits the sample. The absorbed energy causes a thermoelastic expansion and thereby launches a broadband ultrasonic wave (photoacoustic signal). The distribution of absorbed energy density is reconstructed from measurements of the photoacoustic signals around the sample. For collecting photoacoustic signals either point like or extended, integrating detectors can be used. The latter integrate the pressure at least in one dimension, e.g. along a line. Thereby, the three dimensional imaging problem is reduced to a two dimensional problem. For a tomography device consisting of a scanning line detector and a rotating sample, fiber-based detectors made of polymer have been recently introduced. Fiber-based detectors are easy to use and possess a constant, high spatial resolution over their entire active length. Polymer fibers provide a better impedance matching and a better handling compared with glass fibers which were our first approach. First measurement results using polymer fiber detectors and some approaches for improving the performance are presented.

  17. Combination vaccines

    Directory of Open Access Journals (Sweden)

    David AG Skibinski

    2011-01-01

    Full Text Available The combination of diphtheria, tetanus, and pertussis vaccines into a single product has been central to the protection of the pediatric population over the past 50 years. The addition of inactivated polio, Haemophilus influenzae, and hepatitis B vaccines into the combination has facilitated the introduction of these vaccines into recommended immunization schedules by reducing the number of injections required and has therefore increased immunization compliance. However, the development of these combinations encountered numerous challenges, including the reduced response to Haemophilus influenzae vaccine when given in combination; the need to consolidate the differences in the immunization schedule (hepatitis B; and the need to improve the safety profile of the diphtheria, tetanus, and pertussis combination. Here, we review these challenges and also discuss future prospects for combination vaccines.

  18. Polymeric Medical Sutures: An Exploration of Polymers and Green Chemistry

    Science.gov (United States)

    Knutson, Cassandra M.; Schneiderman, Deborah K.; Yu, Ming; Javner, Cassidy H.; Distefano, Mark D.; Wissinger, Jane E.

    2017-01-01

    With new K-12 national science standards emerging, there is an increased need for experiments that integrate engineering into the context of society. Here we describe a chemistry experiment that combines science and engineering principles while introducing basic polymer and green chemistry concepts. Using medical sutures as a platform for…

  19. Tribological performance of polymer composites used in electrical ...

    Indian Academy of Sciences (India)

    GFR) polymer composite. Wear test was carried out at 10, 20 and 30 N applied load values and 0·5 m/s sliding speed and at ambient temperature and humidity. Different combinations of rubbing surfaces were examined and friction coefficient and ...

  20. Supramolecular materials based on hydrogen-bonded polymers

    NARCIS (Netherlands)

    ten Brinke, Gerrit; Ruokolainen, Janne; Ikkala, Olli; Binder, W

    2007-01-01

    Combining supramolecular principles with block copolymer self-assembly offers unique possibilities to create materials with responsive and/or tunable properties. The present chapter focuses on supramolecular materials based on hydrogen bonding and (block co-) polymers. Several cases will be

  1. Tribological performance of polymer composites used in electrical ...

    Indian Academy of Sciences (India)

    These are AISI 316 L stainless steel and 30% glass fibre-reinforced polyphenylenesulphide (PPS + 30%GFR) polymer composite. Wear test was carried out at 10, 20 and 30 N applied load values and 0.5 m/s sliding speed and at ambient temperature and humidity. Different combinations of rubbing surfaces were examined ...

  2. Bond strength investigation of two shot moulded polymer

    DEFF Research Database (Denmark)

    Islam, Mohammad Aminul

    This report on the project “Bond strength investigation of two shot moulded polymers” has been submitted for fulfilling the requirements for the course “Experimental Plastic Technology – 42234” at IPL-DTU. Two shot moulding is a classic manufacturing process to combine two different polymers...

  3. Semi-Crystalline Polymer based Single Walled Carbon Nanotube Nanocomposites

    Science.gov (United States)

    Mitchell, Cynthia; Krishnamoorti, Ramanan

    2004-03-01

    The reinforcement of polymers with nanometer scale inorganic materials has stimulated much scientific and technological interest because, when compared to traditional composites, nanocomposites exhibit improved thermal, mechanical and physical properties at much lower particle loading. Development of single walled carbon nanotube (SWNT) based polymer nanocomposites is attractive because of the possibility of combining the extraordinary array of properties of SWNTs with the light-weight character of polymers to develop unique and tailorable materials. Important areas of concern in the development of SWNT composites are ensuring homogeneity of dispersion, good interfacial compatibility with the polymeric matrix and the exfoliation of the ropes and bundles. Several strategies for developing well-dispersed SWNT polymer nanocomposites have been undertaken in the current research and we demonstrate the development of well dispersed SWNT nanocomposites with poly(e-caprolactone) (PCL). PCL is a model, low melting analog of nylon-6, an important commercial material, and additionally is a biocompatible and biodegradable crystalline polymer. Compatibility between PCL and SWNT is anticipated based on the fact that the monomer e-caprolactone disperses SWNTs effectively. Preparation of the composites was accomplished by in-situ polymerization and also by solution blending a model polymer with functionalized or unfunctionalized SWNTs. Composites were characterized extensively utilizing UV- Vis - NearIR spectroscopy, FTIR, DSC, X-ray scattering and diffraction, AFM, melt state rheology and electrical conductivity. Controlling the interactions by covalently linking the polymer to the nanotube or by use of a dispersing aid before the introduction of the polymer and the extensive characterization of the resulting system could lead to the development of structure property relationships that would be beneficial to the tailoring of ultra lightweight materials with exceptional mechanical

  4. Polymer dye lasers

    DEFF Research Database (Denmark)

    Balslev, Søren

    2006-01-01

    Formålet med dette Ph.D. arbejde har været at udvikle miniaturiserede polymer farvestoflasere, egnet til at blive integreret i mikrochips som også indeholder andre polymerstrukturer – som for eksempel kan findes i ”Laboratorie-på-en-chip” kredsløb. Lasernes funktion skal være at levere lys til...... meget følsomme sensorformål, og at undgå at skulle opliniere eksterne lyskilder til sensorer på polymerchips. En enkelt type gennemsigtig ”resist” (SU-8) er blevet brugt til at udvikle en række laserresonatorer i polymer. ”Resisten” er blevet formgivet via en række lithografiske teknikker: UV lithografi......, elektronstrålelithografi og Röntgenstrålelithografi. Andre polymerer er også blevet formgivet via ”nanoimprint” lithografi for at skabe laserresonatorer. En række lasere, både baseret på et flydende forstærkningsmedium og et faststof forstærkningsrmedium er blevet udviklet. Laserne giver både lys i flere ”modes” og i een...

  5. Computational modelling of polymers

    Science.gov (United States)

    Celarier, Edward A.

    1991-01-01

    Polymeric materials and polymer/graphite composites show a very diverse range of material properties, many of which make them attractive candidates for a variety of high performance engineering applications. Their properties are ultimately determined largely by their chemical structure, and the conditions under which they are processed. It is the aim of computational chemistry to be able to simulate candidate polymers on a computer, and determine what their likely material properties will be. A number of commercially available software packages purport to predict the material properties of samples, given the chemical structures of their constituent molecules. One such system, Cerius, has been in use at LaRC. It is comprised of a number of modules, each of which performs a different kind of calculation on a molecule in the programs workspace. Particularly, interest is in evaluating the suitability of this program to aid in the study of microcrystalline polymeric materials. One of the first model systems examined was benzophenone. The results of this investigation are discussed.

  6. Supramolecular networks of telechelic polymers

    NARCIS (Netherlands)

    Bohdan, M.A.

    2016-01-01

    This thesis focuses on the fundamental understanding of phenomena associated with the gelation of end-functionalized polymers and the dynamic processes occurring inside of the gel network. To address particular questions we use two types of telechelic polymers, in which the assembly occurs due to

  7. Efficient simulation of semiflexible polymers

    NARCIS (Netherlands)

    Panja, Deb; Barkema, Gerard T.; van Leeuwen, J. M. J.

    2015-01-01

    Using a recently developed bead-spring model for semiflexible polymers that takes into account their natural extensibility, we report an efficient algorithm to simulate the dynamics for polymers like double-stranded DNA (dsDNA) in the absence of hydrodynamic interactions. The dsDNA is modeled with

  8. Photoluminescence quenching of semiconducting polymer ...

    Indian Academy of Sciences (India)

    ing of decay time regarding polymer nanoparticles in presence of Au nanoparticles suggest the nonradiative energy transfer process. The values of energy transfer are 6·7%, 49·5% and 53·38% from PVK polymer nanoparticles to. 3 nm, 14 nm and 18 nm Au nanoparticles, respectively. Using FRET and SET equations we ...

  9. Statistical properties of curved polymer

    Indian Academy of Sciences (India)

    Intrinsic curvature of biopolymers is emerging as an essential feature in various biological phenomena. Examples of polymers with intrinsic curvature are microtubule in eukaryotic cells or FtsZ filaments in prokaryotic cells. We consider the general model for polymers with intrinsic curvature. We aim to study both equilibrium ...

  10. Hydrophilic polymers for drug delivery

    Czech Academy of Sciences Publication Activity Database

    Ulbrich, Karel; Šubr, Vladimír; Pechar, Michal; Strohalm, Jiří; Jelínková, Markéta; Říhová, Blanka

    2000-01-01

    Roč. 152, - (2000), s. 151-162 ISSN 1022-1360. [European Polymer Federation Symposium on Polymeric Materials: Polymers Friendly for the Environment /7./. Szczecin, 20.09.1998-24.09.1998] R&D Projects: GA ČR GV307/96/K226 Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.406, year: 2000

  11. Statistical properties of curved polymer

    Indian Academy of Sciences (India)

    Abstract. Intrinsic curvature of biopolymers is emerging as an essential feature in vari- ous biological phenomena. Examples of polymers with intrinsic curvature are microtubule in eukaryotic cells or FtsZ filaments in prokaryotic cells. We consider the general model for polymers with intrinsic curvature. We aim to study both ...

  12. Radiation synthesis of polymer polyol

    International Nuclear Information System (INIS)

    Guo Jianmei; Zeng Xinmiao; Zhou Chengfei; Cao Wei; Zhai Tong; Wu Dezhen

    2010-01-01

    The polymer polyol was synthesized by γ irradiation. The properties of polymer polyol synthesized with different radiation dose were studied. The experiment result showed the radiation dose hadn't significant influence on the hydroxyl value of polymer polyol. The sample with different solid content had different hydroxyl value. When the radiation dose is between 1 to 12 kGy, the viscosity and hydroxyl value of polymer polyol were increased with the increment of radiation dose. When radiation dose is between 1 to 12 kGy, with the increment of radiation dose, viscosity of polymer polyol was rapidly increased, and the content solid of sample has few change. When radiation dose is higher than 20 kGy, the viscosity and hydroxyl value of polymer polyol have gradually increase with the increment of radiation dose. The size of polymer particles is 0.1-0.6 μm. The value of 150 mesh filter was 100%. The polymer polyol may be used as PU foam and elastomer. (authors)

  13. HIGH TEMPERATURE POLYMER FUEL CELLS

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Qingfeng, Li; He, Ronghuan

    2003-01-01

    This paper will report recent results from our group on polymer fuel cells (PEMFC) based on the temperature resistant polymer polybenzimidazole (PBI), which allow working temperatures up to 200°C. The membrane has a water drag number near zero and need no water management at all. The high working...

  14. Natural fibres-based polymers

    Indian Academy of Sciences (India)

    Natural fibres-based polymers: Part I—Mechanical analysis of Pine needles reinforced biocomposites. Vijay Kumar Thakur A S ... Keeping in view the various advantages of natural fibres, in current series of green composites a study on natural fibre reinforced polymer composites has been made. This paper presents the ...

  15. Photo-Healable Metallosupramolecular Polymers

    Science.gov (United States)

    2014-01-09

    Ohio Invited Lecture: Structurally Dynamic Polymers as a Route to Stimuli-Responsive Materials Apr. 2013 ACS PMSE /Chinese Chemical Society meeting...Mark Burnworth, Liming Tang, Stuart J. Rowan, Christoph Weder. Reinforcement of Self- Healing Polymer Films with Cellulose Nanowhiskers, ACS PMSE

  16. Wood and concrete polymer composites

    International Nuclear Information System (INIS)

    Singer, K.

    1974-01-01

    There are several ways to prepare and use wood and concrete polymer composites. The most important improvements in the case of concrete polymer composites are obtained for compressive and tensile strengths. The progress in this field in United States and other countries is discussed in this rview. (M.S.)

  17. COUPLING THE ALKALINE-SURFACTANT-POLYMER TECHNOLOGY AND THE GELATION TECHNOLOGY TO MAXIMIZE OIL PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm Pitts; Jie Qui; Dan Wilson; Phil Dowling

    2004-05-01

    Gelation technologies have been developed to provide more efficient vertical sweep efficiencies for flooding naturally fractured oil reservoirs or more efficient areal sweep efficiency those with high permeability contrast ''thief zones''. The field proven alkaline-surfactant-polymer technology economically recovers 15% to 25% OOIP more oil than waterflooding in the swept pore space of an oil reservoir. However, alkaline-surfactant-polymer technology is not amenable to the naturally fractured reservoirs or those with thief zones because much of the injected solution bypasses the target pore space containing oil. The objective of this work is to investigate whether combining these two technologies could broaden the applicability of alkaline-surfactant-polymer flooding into these reservoirs. Fluid-fluid interaction with different gel chemical compositions and alkaline-surfactant-polymer solution with pH values ranging from 9.2 to 12.9 have been tested. Aluminum-polyacrylamide gels are not stable to alkaline-surfactant-polymer solutions at any pH. Chromium--polyacrylamide gels with polymer to chromium ion ratios of 25 or greater were stable to alkaline-surfactant-polymer solutions if solution pH was 10.6 or less. When the polymer to chromium ion was 15 or less, chromium-polyacrylamide gels were stable to alkaline-surfactant-polymer solutions with pH values up to 12.9. Chromium-xanthan gum gels were stable to alkaline-surfactant-polymer solutions with pH values of 12.9 at the polymer to chromium ion ratios tested. Silicate-polyacrylamide, resorcinol-formaldehyde, and sulfomethylated resorcinol-formaldehyde gels were also stable to alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Iron-polyacrylamide gels were immediately destroyed when contacted with any of the alkaline-surfactant-polymer solutions with pH values of 9.2 to 12.9.

  18. Understanding Polymer-Cell Attachment.

    Science.gov (United States)

    Venturato, Andrea; MacFarlane, Gillian; Geng, Jin; Bradley, Mark

    2016-12-01

    The development of polymeric materials with cell adhesion abilities requires an understanding of cell-surface interactions which vary with cell type. To investigate the correlation between cell attachment and the nature of the polymer, a series of random and block copolymers composed of 2-(dimethylamino)ethyl acrylate and ethyl acrylate are synthesized through single electron transfer living radical polymerization. The polymers are synthesized with highly defined and controlled monomer compositions and exhibited narrow polydispersity indices. These polymers are examined for their performance in the attachment and growth of HeLa and HEK cells, with attachment successfully modeled on monomer composition and polymer chain length, with both cell lines found to preferentially attach to moderately hydrophobic functional materials. The understanding of the biological-material interactions assessed in this study will underpin further investigations of engineered polymer scaffolds with predictable cell binding performance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Controlled Release from Recombinant Polymers

    Science.gov (United States)

    Price, Robert; Poursaid, Azadeh; Ghandehari, Hamidreza

    2014-01-01

    Recombinant polymers provide a high degree of molecular definition for correlating structure with function in controlled release. The wide array of amino acids available as building blocks for these materials lend many advantages including biorecognition, biodegradability, potential biocompatibility, and control over mechanical properties among other attributes. Genetic engineering and DNA manipulation techniques enable the optimization of structure for precise control over spatial and temporal release. Unlike the majority of chemical synthetic strategies used, recombinant DNA technology has allowed for the production of monodisperse polymers with specifically defined sequences. Several classes of recombinant polymers have been used for controlled drug delivery. These include, but are not limited to, elastin-like, silk-like, and silk-elastinlike proteins, as well as emerging cationic polymers for gene delivery. In this article, progress and prospects of recombinant polymers used in controlled release will be reviewed. PMID:24956486

  20. Accelerated Characterization of Polymer Properties

    Energy Technology Data Exchange (ETDEWEB)

    R. Wroczynski; l. Brewer; D. Buckley; M. Burrell; R. Potyrailo

    2003-07-30

    This report describes the efforts to develop a suite of microanalysis techniques that can rapidly measure a variety of polymer properties of industrial importance, including thermal, photo-oxidative, and color stability; as well as ductility, viscosity, and mechanical and antistatic properties. Additional goals of the project were to direct the development of these techniques toward simultaneous measurements of multiple polymer samples of small size in real time using non-destructive and/or parallel or rapid sequential measurements, to develop microcompounding techniques for preparing polymers with additives, and to demonstrate that samples prepared in the microcompounder could be analyzed directly or used in rapid off-line measurements. These enabling technologies are the crucial precursors to the development of high-throughput screening (HTS) methodologies for the polymer additives industry whereby the rate of development of new additives and polymer formulations can be greatly accelerated.

  1. Ion beam modification of polymers

    International Nuclear Information System (INIS)

    Sofield, C.J.; Sugden, S.; Ing, J.; Bridwell, L.B.; Wang, Y.Q.

    1993-01-01

    The implantation of polymers has received considerable attention in recent years, primarily to examine doping of conducting polymers and to increase the surface conductivity (by many orders of magnitude) of highly insulating polymers. The interest in these studies was partly motivated by possible applications to microelectronic device fabrication. More recently it has been observed that ion implantation can under some conditions lead to the formation of a hard (e.g. as hard as steel, ca. 3 MPa) and conducting surface layer. This paper will review the ion beam modification of polymers resulting from ion implantation with reference to fundamental ion-solid interactions. This leads us to examine whether or not implantation of polymers is a contradiction in terms. (Author)

  2. Nanorheology of Entangled Polymer Melts

    Science.gov (United States)

    Ge, Ting; Grest, Gary S.; Rubinstein, Michael

    2018-02-01

    We use molecular simulations to probe the local viscoelasticity of an entangled polymer melt by tracking the motion of embedded nonsticky nanoparticles (NPs). As in conventional microrheology, the generalized Stokes-Einstein relation is employed to extract an effective stress relaxation function GGSE(t ) from the mean square displacement of NPs. GGSE(t ) for different NP diameters d are compared with the stress relaxation function G (t ) of a pure polymer melt. The deviation of GGSE(t ) from G (t ) reflects the incomplete coupling between NPs and the dynamic modes of the melt. For linear polymers, a plateau in GGSE(t ) emerges as d exceeds the entanglement mesh size a and approaches the entanglement plateau in G (t ) for a pure melt with increasing d . For ring polymers, as d increases towards the spanning size R of ring polymers, GGSE(t ) approaches G (t ) of the ring melt with no entanglement plateau.

  3. The Role of Electron Affinity in Determining Whether Fullerenes Catalyze or Inhibit Photooxidation of Polymers for Solar Cells

    KAUST Repository

    Hoke, Eric T.

    2012-05-21

    Understanding the stability and degradation mechanisms of organic solar materials is critically important to achieving long device lifetimes. Here, an investigation of the photodegradation of polymer:fullerene blend fi lms exposed to ambient conditions for a variety of polymer and fullerene derivative combinations is presented. Despite the wide range in polymer stabilities to photodegradation, the rate of irreversible polymer photobleaching in blend fi lms is found to consistently and dramatically increase with decreasing electron affi nity of the fullerene derivative. Furthermore, blends containing fullerenes with the smallest electron affi nities photobleached at a faster rate than fi lms of the pure polymer. These observations can be explained by a mechanism where both the polymer and fullerene donate photogenerated electrons to diatomic oxygen to form the superoxide radical anion which degrades the polymer. © 2012 WILEY-VCH Verlag GmbH & Co.

  4. Polymer Tribology: Current State and Applications

    Directory of Open Access Journals (Sweden)

    N.K. Myshkin

    2015-09-01

    Full Text Available Polymer tribology is based on the analysis of abrasion, adhesion, and fatigue of polymer materials in a friction contact. The structural features of polymers provide a variety of tribological applications of basic polymers mostly as matrices and fillers of composite materials. Recently polymer nanocomposites are used for making components of various tribosystems. A short review of polymer materials for tribosystems is presented. The main results of studies in friction and wear of polymers are given. Formation of the real area of contact is evaluated when taking account of polymer viscoelasticity and the effects of temperature and load in the contact. Adhesion of polymers and its part in friction transfer is considered. Various aspects of friction and wear tests of polymer materials for estimation of their characteristics, prediction of service life in different operational conditions are discussed. Practical examples of applications of polymer composites and nanocomposites in various branches of industry are given.

  5. EDITORIAL: Electroactive polymer materials

    Science.gov (United States)

    Bar-Cohen, Yoseph; Kim, Kwang J.; Ryeol Choi, Hyouk; Madden, John D. W.

    2007-04-01

    Imitating nature's mechanisms offers enormous potential for the improvement of our lives and the tools we use. This field of the study and imitation of, and inspiration from, nature's methods, designs and processes is known as biomimetics. Artificial muscles, i.e. electroactive polymers (EAPs), are one of the emerging technologies enabling biomimetics. Polymers that can be stimulated to change shape or size have been known for many years. The activation mechanisms of such polymers include electrical, chemical, pneumatic, optical and magnetic. Electrical excitation is one of the most attractive stimulators able to produce elastic deformation in polymers. The convenience and practicality of electrical stimulation and the continual improvement in capabilities make EAP materials some of the most attractive among activatable polymers (Bar-Cohen Y (ed) 2004 Electroactive Polymer (EAP) Actuators as Artificial Muscles—Reality, Potential and Challenges 2nd edn, vol PM136 (Bellingham, WA: SPIE Press) pp 1-765). As polymers, EAP materials offer many appealing characteristics that include low weight, fracture tolerance and pliability. Furthermore, they can be configured into almost any conceivable shape and their properties can be tailored to suit a broad range of requirements. These capabilities and the significant change of shape or size under electrical stimulation while being able to endure many cycles of actuation are inspiring many potential possibilities for EAP materials among engineers and scientists in many different disciplines. Practitioners in biomimetics are particularly excited about these materials since they can be used to mimic the movements of animals and insects. Potentially, mechanisms actuated by EAPs will enable engineers to create devices previously imaginable only in science fiction. For many years EAP materials received relatively little attention due to their poor actuation capability and the small number of available materials. In the last fifteen

  6. Polymers – A New Open Access Scientific Journal on Polymer Science

    Directory of Open Access Journals (Sweden)

    Shu-Kun Lin

    2009-12-01

    Full Text Available Polymers is a new interdisciplinary, Open Access scientific journal on polymer science, published by Molecular Diversity Preservation International (MDPI. This journal welcomes manuscript submissions on polymer chemistry, macromolecular chemistry, polymer physics, polymer characterization and all related topics. Both synthetic polymers and natural polymers, including biopolymers, are considered. Manuscripts will be thoroughly peer-reviewed in a timely fashion, and papers will be published, if accepted, within 6 to 8 weeks after submission. [...

  7. SULFUR POLYMER ENCAPSULATION.

    Energy Technology Data Exchange (ETDEWEB)

    KALB, P.

    2001-08-22

    Sulfur polymer cement (SPC) is a thermoplastic polymer consisting of 95 wt% elemental sulfur and 5 wt% organic modifiers to enhance long-term durability. SPC was originally developed by the U.S. Bureau of Mines as an alternative to hydraulic cement for construction applications. Previous attempts to use elemental sulfur as a construction material in the chemical industry failed due to premature degradation. These failures were caused by the internal stresses that result from changes in crystalline structure upon cooling of the material. By reacting elemental sulfur with organic polymers, the Bureau of Mines developed a product that successfully suppresses the solid phase transition and significantly improves the stability of the product. SPC, originally named modified sulfur cement, is produced from readily available, inexpensive waste sulfur derived from desulfurization of both flue gases and petroleum. The commercial production of SPC is licensed in the United States by Martin Resources (Odessa, Texas) and is marketed under the trade name Chement 2000. It is sold in granular form and is relatively inexpensive ({approx}$0.10 to 0.12/lb). Application of SPC for the treatment of radioactive, hazardous, and mixed wastes was initially developed and patented by Brookhaven National Laboratory (BNL) in the mid-1980s (Kalb and Colombo, 1985; Colombo et al., 1997). The process was subsequently investigated by the Commission of the European Communities (Van Dalen and Rijpkema, 1989), Idaho National Engineering Laboratory (Darnell, 1991), and Oak Ridge National Laboratory (Mattus and Mattus, 1994). SPC has been used primarily in microencapsulation applications but can also be used for macroencapsulation of waste. SPC microencapsulation has been demonstrated to be an effective treatment for a wide variety of wastes, including incinerator hearth and fly ash; aqueous concentrates such as sulfates, borates, and chlorides; blowdown solutions; soils; and sludges. It is not

  8. Hybrid polymer photonic crystal fiber with integrated chalcogenide glass nanofilms

    DEFF Research Database (Denmark)

    Markos, Christos; Kubat, Irnis; Bang, Ole

    2014-01-01

    The combination of chalcogenide glasses with polymer photonic crystal fibers (PCFs) is a difficult and challenging task due to their different thermo-mechanical material properties. Here we report the first experimental realization of a hybrid polymer-chalcogenide PCF with integrated As2S3 glass...... nanofilms at the inner surface of the air-channels of a poly-methyl-methacrylate (PMMA) PCF. The integrated high refractive index glass films introduce distinct antiresonant transmission bands in the 480-900 nm wavelength region. We demonstrate that the ultra-high Kerr nonlinearity of the chalcogenide glass...

  9. Self-healing polymers

    Science.gov (United States)

    Klein, Daniel J. (Inventor)

    2011-01-01

    A three dimensional structure fabricated from a self-healing polymeric material, comprising poly(ester amides) obtained from ethylene glycol, azelaic acid and 1,1-aminoundecanoic acid, wherein polymeric material has a melt index above 2.5 g/10 min. as determined by ASTM D1238 at 190.degree. C. and 2.16kg, impact resistance and ductility sufficient to resist cracking and brittle fracture upon impact by a 9 mm bullet fired at a temperature of about 29.degree. C. at subsonic speed in a range from about 800 feet/sec to about 1000 feet/sec. It has been determined that the important factors necessary for self-healing behavior of polymers include sufficient impact strength, control of the degree of crystallinity, low melting point and the ability to instantly melt at impacted area.

  10. Protein Polymers and Amyloids

    DEFF Research Database (Denmark)

    Risør, Michael Wulff

    2014-01-01

    Several human disorders are caused by a common general disease mechanism arising from abnormal folding and aggregation of the underlying protein. These include the prevalent dementias like Alzheimer’s and Parkinson’s, where accumulation of protein fibrillar structures, known as amyloid fibrils...... that inhibits its target protease through a large conformational change but mutations compromise this function and cause premature structural collapse into hyperstable polymers. Understanding the conformational disorders at a molecular level is not only important for our general knowledge on protein folding......, underlining the importance of understanding this relationship. The monomeric C-36 peptide was investigated by liquid-state NMR spectroscopy and found to be intrinsically disordered with minor propensities towards β-sheet structure. The plasticity of such a peptide makes it suitable for a whole range...

  11. Biomedical Shape Memory Polymers

    Directory of Open Access Journals (Sweden)

    SHEN Xue-lin

    2017-07-01

    Full Text Available Shape memory polymers(SMPs are a class of functional "smart" materials that have shown bright prospects in the area of biomedical applications. The novel smart materials with multifunction of biodegradability and biocompatibility can be designed based on their general principle, composition and structure. In this review, the latest process of three typical biodegradable SMPs(poly(lactide acide, poly(ε-caprolactone, polyurethane was summarized. These three SMPs were classified in different structures and discussed, and shape-memory mechanism, recovery rate and fixed rate, response speed was analysed in detail, also, some biomedical applications were presented. Finally, the future development and applications of SMPs are prospected: two-way SMPs and body temperature induced SMPs will be the focus attension by researchers.

  12. Conducting Polymer Based Nanobiosensors

    Directory of Open Access Journals (Sweden)

    Chul Soon Park

    2016-06-01

    Full Text Available In recent years, conducting polymer (CP nanomaterials have been used in a variety of fields, such as in energy, environmental, and biomedical applications, owing to their outstanding chemical and physical properties compared to conventional metal materials. In particular, nanobiosensors based on CP nanomaterials exhibit excellent performance sensing target molecules. The performance of CP nanobiosensors varies based on their size, shape, conductivity, and morphology, among other characteristics. Therefore, in this review, we provide an overview of the techniques commonly used to fabricate novel CP nanomaterials and their biosensor applications, including aptasensors, field-effect transistor (FET biosensors, human sense mimicking biosensors, and immunoassays. We also discuss prospects for state-of-the-art nanobiosensors using CP nanomaterials by focusing on strategies to overcome the current limitations.

  13. Electrochromic in conjugated polymers

    International Nuclear Information System (INIS)

    Picado Valenzuela, Alfredo

    2007-01-01

    This revision considered object the description of one of the materials with the greatest potential in the field of electrochromic (mainly in the visible region): the conjugated polymers (CP), area of enormous potential both now and in a short time ahead. The CP are insulating materials and organic semiconductors in a state not doped. They can be doped positively or negatively being observed a significant increase in the conductivity and being generated a color change in these materials. The understanding of how optical properties vary based on the chemical structure of the polymer or its mixtures and more precisely of the alternatives that can be entered into the conjugated system or π system to obtain a material that besides to be flexible, environmentally stable, presents the colored states. The revision was centred chiefly in the polypyrrole (Ppy), the polythiophene (PTh) and their derivatives such as poly (3.4-ethylenedioxythiophene) (PEDOT). The advantage of using monomers with variable structure, to adjust the composition of the copolymer, or to blend with the PC, allows to obtain a variety of colored states that can be modulated through the visible spectrum and even with applications to wavelengths outside of this region. Because the PC presented at least two different colored states can be varied continuously as a function of the voltage applied. In some cases, they may submit multicoloured statements, which offers a range of possibilities for their application in flexible electronic devices type screens and windows. Applications include smart windows, camouflage clothing and data screens. This type of material is emerging as one of the substitutes of the traditional inorganic semiconductor, with the advantage of its low cost, high flexibility and the possibility to generate multiple colors through the handling of the monomers in the structure and control of energy of his band gap. (author) [es

  14. More Than Just a Polymer

    Science.gov (United States)

    2001-01-01

    Triton atomic Oxygen Resistant polymers TOR(TM), were developed by Chelmsford, Massachusetts-based Triton Systems, Inc., through a Small Business Innovation Research (SBIR) contract from NASA's Langley Research Center. The new family of polymers comes from a Langley-developed polymer technology, which marks a new class of aerospace materials that resist the extreme effects of low Earth orbit (LEO). When applied to spacecraft surfaces, TOR polymers protect against erosion caused by the atomic oxygen and radiation present in space. Other polymers, such as Teflon(R) and Kapton(R), are subject to degradation from atomic oxygen and ultraviolet radiation, but TOR polymers use atomic oxygen to their advantage. A long-lasting protective barrier means major savings in the cost of spacecraft maintenance and the time spent performing repairs. While the obvious application of this material lies with the aerospace industry, an underlying benefit is found in the field of electronics. TOR polymers can be made electrically conductive, and then utilized in the creation of sensors that react to the presence of chemical and biological agents by exhibiting a detectable change in electrical conductivity. These sensors have applications in the defense, medical, and industrial sectors.

  15. Monitoring of polymer melt processing

    International Nuclear Information System (INIS)

    Alig, Ingo; Steinhoff, Bernd; Lellinger, Dirk

    2010-01-01

    The paper reviews the state-of-the-art of in-line and on-line monitoring during polymer melt processing by compounding, extrusion and injection moulding. Different spectroscopic and scattering techniques as well as conductivity and viscosity measurements are reviewed and compared concerning their potential for different process applications. In addition to information on chemical composition and state of the process, the in situ detection of morphology, which is of specific interest for multiphase polymer systems such as polymer composites and polymer blends, is described in detail. For these systems, the product properties strongly depend on the phase or filler morphology created during processing. Examples for optical (UV/vis, NIR) and ultrasonic attenuation spectra recorded during extrusion are given, which were found to be sensitive to the chemical composition as well as to size and degree of dispersion of micro or nanofillers in the polymer matrix. By small-angle light scattering experiments, process-induced structures were detected in blends of incompatible polymers during compounding. Using conductivity measurements during extrusion, the influence of processing conditions on the electrical conductivity of polymer melts with conductive fillers (carbon black or carbon nanotubes) was monitored. (topical review)

  16. Combination Vaccines

    OpenAIRE

    Skibinski, David AG; Baudner, Barbara C; Singh, Manmohan; O’Hagan, Derek T

    2011-01-01

    The combination of diphtheria, tetanus, and pertussis vaccines into a single product has been central to the protection of the pediatric population over the past 50 years. The addition of inactivated polio, Haemophilus influenzae, and hepatitis B vaccines into the combination has facilitated the introduction of these vaccines into recommended immunization schedules by reducing the number of injections required and has therefore increased immunization compliance. However, the development of th...

  17. Current Status of Methods Used In Degradation of Polymers: A Review

    Directory of Open Access Journals (Sweden)

    Kulkarni Aishwarya

    2018-01-01

    Full Text Available Degradation of different polymers now a day is the most crucial thing to carry out. It possesses threats to human health as well as to the environment. Different polymers like PVA, PVC, and PP with high density and low density are one of the most consumed by population and also their degradation is a bit difficult. For this many people have started working on effective methods of degradation of these polymers. This can be done by thermal degradation and pyrolysis which requires high temperature, bio degradation using starch, bacteria etc and photo degradation. Traditional gravimetric and respirometric techniques are the methods currently used in testing. They fit readily for degradable polymeric materials usually. Also they are well suited for biodegradable components with polymer blends. But the recent polymer generation is comparatively resistant to bio degradation of polymers hence they cannot be used here. The polymer matrices are readily present in the plasticizers boosting the strength of polymeric material hence in addition; there is the mechanism of degradation. The information on various methods discussed in this review is planned to illustrate a best fit of methods for those who are interested in testing the degradation of polymers under different environmental conditions and selection of appropriate technique for specific combination of mixture of polymer and catalysts which helps to degrade the polymeric material.

  18. Coupling the Alkaline-Surfactant-Polymer Technology and The Gelation Technology to Maximize Oil Production

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm Pitts; Jie Qi; Dan Wilson; Phil Dowling; David Stewart; Bill Jones

    2005-12-01

    Performance and produced polymer evaluation of four alkaline-surfactant-polymer projects concluded that only one of the projects could have benefited from combining the alkaline-surfactant-polymer and gelation technologies. Cambridge, the 1993 Daqing, Mellott Ranch, and the Wardlaw alkaline-surfacant-polymer floods were studied. An initial gel treatment followed by an alkaline-surfactant-polymer flood in the Wardlaw field would have been a benefit due to reduction of fracture flow. Numerical simulation demonstrated that reducing the permeability of a high permeability zone of a reservoir with gel improved both waterflood and alkaline-surfactant-polymer flood oil recovery. A Minnelusa reservoir with both A and B sand production was simulated. A and B sands are separated by a shale layer. A sand and B sand waterflood oil recovery was improved by 196,000 bbls or 3.3% OOIP when a gel was placed in the B sand. Alkaline-surfactant-polymer flood oil recovery improvement over a waterflood was 392,000 bbls or 6.5% OOIP. Placing a gel into the B sand prior to an alkaline-surfactant-polymer flood resulted in 989,000 bbl or 16.4% OOIP more oil than only water injection. A sand and B sand alkaline-surfactant-polymer flood oil recovery was improved by 596,000 bbls or 9.9% OOIP when a gel was placed in the B sand.

  19. Amphiphilic polymers formed from ring-opening polymerization: a strategy for the enhancement of gene delivery.

    Science.gov (United States)

    Zhang, Yi-Mei; Huang, Zheng; Zhang, Ji; Wu, Wan-Xia; Liu, Yan-Hong; Yu, Xiao-Qi

    2017-03-28

    Cationic liposomes and polymers are both important candidates for use as non-viral gene vectors. However, both of them have special shortcomings and application limits. This work is devoted to the combination of advantages of liposomes and polymers. The ring-opening polymerization strategy was used for the preparation of amphiphilic polymers from cyclen-based cationic small lipids. The non-hydrophobic polymer and the corresponding lipids were also prepared for performing structure-activity relationship studies. Gel electrophoresis results reveal that both the lipopolymers and liposomes could effectively condense DNA into nanoparticles and protect DNA from degradation. Compared to polymers, the DNA binding ability of liposomes is more affected by hydrophobic tails. Under the same dosage, the synthetic polymers have stronger DNA binding ability than the liposomes. In vitro transfection experiments show that the polymers could give better transfection efficiency, which was much higher than those of the corresponding liposomes and non-hydrophobic polymer. The oleyl moiety is suitable for lipidic vectors, but things were different for polymers. Under optimized conditions, up to 14.2 times higher transfection efficiency than that for 25 kDa bPEI could be obtained. More importantly, the lipopolymers showed much better serum tolerance, which was further confirmed by protein adsorption, gel electrophoresis, flow cytometry, and CLSM assays. The results indicate that ring-opening polymerization is a promising strategy for the enhancement of the gene delivery efficiency and biocompatibility of cationic lipids.

  20. Mechanical Properties of Polymer Concrete

    Directory of Open Access Journals (Sweden)

    Raman Bedi

    2013-01-01

    Full Text Available Polymer concrete was introduced in the late 1950s and became well known in the 1970s for its use in repair, thin overlays and floors, and precast components. Because of its properties like high compressive strength, fast curing, high specific strength, and resistance to chemical attacks polymer concrete has found application in very specialized domains. Simultaneously these materials have been used in machine construction also where the vibration damping property of polymer concrete has been exploited. This review deals with the efforts of various researchers in selection of ingredients, processing parameters, curing conditions, and their effects on the mechanical properties of the resulting material.

  1. Direct Photopatterning of Electrochromic Polymers

    DEFF Research Database (Denmark)

    Jensen, Jacob; Dyer, Aubrey L.; Shen, D. Eric

    2013-01-01

    . Electrochemical, spectroelectrochemical, and colorimetric analyses of the crosslinked polymer films are performed to establish that they retain the same electrochromic qualities as the parent polymers with no detriment to the observed properties. To demonstrate applicability for multi‐film processing...... show excellent film forming abilities, with thin films prepared using both spray‐casting and spin‐coating. These polymers are demonstrated to crosslink upon UV irradiation at 350 nm, in the presence of an appropriate photoinitiator, to render the films insoluble to common organic solvents...

  2. Multilayer Electroactive Polymer Composite Material

    Science.gov (United States)

    Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

    2011-01-01

    An electroactive material comprises multiple layers of electroactive composite with each layer having unique dielectric, electrical and mechanical properties that define an electromechanical operation thereof when affected by an external stimulus. For example, each layer can be (i) a 2-phase composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation, or (ii) a 3-phase composite having the elements of the 2-phase composite and further including a third component of micro-sized to nano-sized particles of an electroactive ceramic incorporated in the polymer matrix.

  3. Thermoresponsive Polymers for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Theoni K. Georgiou

    2011-08-01

    Full Text Available Thermoresponsive polymers are a class of “smart” materials that have the ability to respond to a change in temperature; a property that makes them useful materials in a wide range of applications and consequently attracts much scientific interest. This review focuses mainly on the studies published over the last 10 years on the synthesis and use of thermoresponsive polymers for biomedical applications including drug delivery, tissue engineering and gene delivery. A summary of the main applications is given following the different studies on thermoresponsive polymers which are categorized based on their 3-dimensional structure; hydrogels, interpenetrating networks, micelles, crosslinked micelles, polymersomes, films and particles.

  4. Physical properties of polymers handbook

    CERN Document Server

    2007-01-01

    This book offers concise information on the properties of polymeric materials, particularly those most relevant to physical chemistry and chemical physics. Extensive updates and revisions to each chapter include eleven new chapters on novel polymeric structures, reinforcing phases in polymers, and experiments on single polymer chains. The study of complex materials is highly interdisciplinary, and new findings are scattered among a large selection of scientific and engineering journals. This book brings together data from experts in the different disciplines contributing to the rapidly growing area of polymers and complex materials.

  5. Physics of photorefraction in polymers

    CERN Document Server

    West, Dave

    2004-01-01

    Photorefractive polymer composites are an unusually sensitive class of photopolymers. Physics of Photorefraction in Polymers describes our current understanding of the physical processes that produce a photorefractive effect in key composite materials. Topics as diverse as charge generation, dispersive charge transport, charge compensation and trapping, molecular diffusion, organic composite structure, and nonlinear optical wave coupling are all developed from a physical perspective. Emphasis is placed on explaining how these physical processes lead to observable properties of the polymers, and the authors discuss various applications, including holographic archiving.

  6. The workshop on conductive polymers: Final report

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    Reports are made by groups on: polyacetylene, polyphenylene, polyaniline, and related systems; molecular, crystallographic, and defect structures in conducting polymers; heterocyclic polymers; synthesis of new and improved conducting polymers; future applications possibilities for conducting polymers; and challenges for improved understanding of properties. (DLC)

  7. Carbon nanotube-polymer composite actuators

    Science.gov (United States)

    Gennett, Thomas [Denver, CO; Raffaelle, Ryne P [Honeoye Falls, NY; Landi, Brian J [Rochester, NY; Heben, Michael J [Denver, CO

    2008-04-22

    The present invention discloses a carbon nanotube (SWNT)-polymer composite actuator and method to make such actuator. A series of uniform composites was prepared by dispersing purified single wall nanotubes with varying weight percents into a polymer matrix, followed by solution casting. The resulting nanotube-polymer composite was then successfully used to form a nanotube polymer actuator.

  8. Single conducting polymer nanowire based conductometric sensors

    Science.gov (United States)

    Bangar, Mangesh Ashok

    cancer marker protein (Cancer Antigen, CA 125) using covalent immobilization for detection of CA 125 in buffer and human blood plasma. Third approach combined electrochemical deposition of conducting polymer and assembly steps into a single step fabrication & functionalization using e-beam lithographically patterned nano-channels. Using this method array of Ppy nanowires were fabricated. Further during fabrication step, by entrapping recognition molecule (avidin) biofunctionalization was achieved. Subsequently these sensors were used for detection of biotinylated single stranded DNA.

  9. Fluorinated Polymers as Smart Materials for Advanced Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Vanessa F. Cardoso

    2018-02-01

    Full Text Available Fluorinated polymers constitute a unique class of materials that exhibit a combination of suitable properties for a wide range of applications, which mainly arise from their outstanding chemical resistance, thermal stability, low friction coefficients and electrical properties. Furthermore, those presenting stimuli-responsive properties have found widespread industrial and commercial applications, based on their ability to change in a controlled fashion one or more of their physicochemical properties, in response to single or multiple external stimuli such as light, temperature, electrical and magnetic fields, pH and/or biological signals. In particular, some fluorinated polymers have been intensively investigated and applied due to their piezoelectric, pyroelectric and ferroelectric properties in biomedical applications including controlled drug delivery systems, tissue engineering, microfluidic and artificial muscle actuators, among others. This review summarizes the main characteristics, microstructures and biomedical applications of electroactive fluorinated polymers.

  10. Triggering activity of catalytic rod-like supramolecular polymers.

    Science.gov (United States)

    Huerta, Elisa; van Genabeek, Bas; Lamers, Brigitte A G; Koenigs, Marcel M E; Meijer, E W; Palmans, Anja R A

    2015-02-23

    Supramolecular polymers based on benzene-1,3,5-tricarboxamides (BTAs) functionalized with an L- or D-proline moiety display high catalytic activity towards aldol reactions in water. High turnover frequencies (TOF) of up to 27×10(-4) s(-1) and excellent stereoselectivities (up to 96% de, up to 99% ee) were observed. In addition, the catalyst could be reused and remained active at catalyst loadings and substrate concentrations as low as 0.1 mol % and 50 mM, respectively. A temperature-induced conformational change in the supramolecular polymer triggers the high activity of the catalyst. The supramolecular polymer's helical sense in combination with the configuration of the proline (L- or D-) is responsible for the observed selectivity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Fast polymer nanorectifiers for inductively coupled RFID tags

    International Nuclear Information System (INIS)

    Majewski, L.A.; Balocco, C.; King, R.; Whitelegg, S.; Song, A.M.

    2008-01-01

    In this article, an alternative approach to high switching speed organic rectifiers based on a semiconducting polymer, poly(dialkylquarterthiophene) (PQT-12) is demonstrated. It is shown that by using a linear array of polymer nanowires with intentionally broken symmetry, nanodevices displaying diode-like I/V characteristics can be obtained. The so-called self-switching devices (SSDs) are single-layered planar structures that can be easily fabricated in a single step of nanolithography. In addition, since SSD arrays possess substantially lower parasitic capacitance between contacts than conventional vertical organic diodes (VODs) and organic thin-film transistors (OTFTs), very high switching speeds may be achieved. As the result of this combination of favourable properties, we have demonstrated polymer nanorectifiers operating with frequencies well in excess of 1 MHz that have the potential to pave the way towards ultra low-cost radio frequency identification (RFID) tags

  12. High performance lignin-acrylonitrile polymer blend materials

    Energy Technology Data Exchange (ETDEWEB)

    Naskar, Amit K.; Tran, Chau D.

    2017-11-14

    A polymer blend material comprising: (i) a lignin component having a weight-average molecular weight of up to 1,000,000 g/mol; and (ii) an acrylonitrile-containing copolymer rubber component comprising acrylonitrile units in combination with diene monomer units, and having an acrylonitrile content of at least 20 mol %; wherein said lignin component is present in an amount of at least 5 wt % and up to about 95 wt % by total weight of components (i) and (ii); and said polymer blend material possesses a tensile yield stress of at least 5 MPa, or a tensile stress of at least 5 MPa at 10% elongation, or a tensile stress of at least 5 MPa at 100% elongation. Methods for producing the polymer blend, molded forms thereof, and articles thereof, are also described.

  13. Electrically conductive, optically transparent polymer/carbon nanotube composites

    Science.gov (United States)

    Connell, John W. (Inventor); Smith, Jr., Joseph G. (Inventor); Harrison, Joycelyn S. (Inventor); Park, Cheol (Inventor); Watson, Kent A. (Inventor); Ounaies, Zoubeida (Inventor)

    2011-01-01

    The present invention is directed to the effective dispersion of carbon nanotubes (CNTs) into polymer matrices. The nanocomposites are prepared using polymer matrices and exhibit a unique combination of properties, most notably, high retention of optical transparency in the visible range (i.e., 400-800 nm), electrical conductivity, and high thermal stability. By appropriate selection of the matrix resin, additional properties such as vacuum ultraviolet radiation resistance, atomic oxygen resistance, high glass transition (T.sub.g) temperatures, and excellent toughness can be attained. The resulting nanocomposites can be used to fabricate or formulate a variety of articles such as coatings on a variety of substrates, films, foams, fibers, threads, adhesives and fiber coated prepreg. The properties of the nanocomposites can be adjusted by selection of the polymer matrix and CNT to fabricate articles that possess high optical transparency and antistatic behavior.

  14. Polymer grouts for plugging lost circulation in geothermal wells.

    Energy Technology Data Exchange (ETDEWEB)

    Galbreath, D. (Green Mountain International, Waynesvile, NC); Mansure, Arthur James; Bauer, Stephen J.

    2004-12-01

    We have concluded a laboratory study to evaluate the survival potential of polymeric materials used for lost circulation plugs in geothermal wells. We learned early in the study that these materials were susceptible to hydrolysis. Through a systematic program in which many potential chemical combinations were evaluated, polymers were developed which tolerated hydrolysis for eight weeks at 500 F. The polymers also met material, handling, cost, and emplacement criteria. This screening process identified the most promising materials. A benefit of this work is that the components of the polymers developed can be mixed at the surface and pumped downhole through a single hose. Further strength testing is required to determine precisely the maximum temperature at which extrusion through fractures or voids causes failure of the lost circulation plug.

  15. Wafer-scale fabrication of polymer distributed feedback lasers

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Schøler, Mikkel; Balslev, Søren

    2006-01-01

    The authors demonstrate wafer-scale, parallel process fabrication of distributed feedback (DFB) polymer dye lasers by two different nanoimprint techniques: By thermal nanoimprint lithography (TNIL) in polymethyl methacrylate and by combined nanoimprint and photolithography (CNP) in SU-8. In both...... techniques, a thin film of polymer, doped with rhodamine-6G laser dye, is spin coated onto a Borofloat glass buffer substrate and shaped into a planar waveguide slab with first order DFB surface corrugations forming the laser resonator. When optically pumped at 532 nm, lasing is obtained in the wavelength...... range between 576 and 607 nm, determined by the grating period. The results, where 13 laser devices are defined across a 10 cm diameter wafer substrate, demonstrate the feasibility of NIL and CNP for parallel wafer-scale fabrication of advanced nanostructured active optical polymer components...

  16. Colloidal lithography for fabricating patterned polymer-brush microstructures

    Directory of Open Access Journals (Sweden)

    Tao Chen

    2012-05-01

    Full Text Available We exploit a series of robust, but simple and convenient colloidal lithography (CL approaches, using a microsphere array as a mask or as a guiding template, and combine this with surface-initiated atom-transfer radical polymerization (SI-ATRP to fabricate patterned polymer-brush microstructures. The advantages of the CL technique over other lithographic approaches for the fabrication of patterned polymer brushes are (i that it can be carried out with commercially available colloidal particles at a relatively low cost, (ii that no complex equipment is required to create the patterned templates with micro- and nanoscale features, and (iii that polymer brush features are controlled simply by changing the size or chemical functionality of the microspheres or the substrate.

  17. Water Soluble Polymers for Pharmaceutical Applications

    Directory of Open Access Journals (Sweden)

    Veeran Gowda Kadajji

    2011-11-01

    Full Text Available Advances in polymer science have led to the development of novel drug delivery systems. Some polymers are obtained from natural resources and then chemically modified for various applications, while others are chemically synthesized and used. A large number of natural and synthetic polymers are available. In the present paper, only water soluble polymers are described. They have been explained in two categories (1 synthetic and (2 natural. Drug polymer conjugates, block copolymers, hydrogels and other water soluble drug polymer complexes have also been explained. The general properties and applications of different water soluble polymers in the formulation of different dosage forms, novel delivery systems and biomedical applications will be discussed.

  18. Understanding Toughness in Bioinspired Cellulose Nanofibril/Polymer Nanocomposites.

    Science.gov (United States)

    Benítez, Alejandro J; Lossada, Francisco; Zhu, Baolei; Rudolph, Tobias; Walther, Andreas

    2016-07-11

    Cellulose nanofibrils (CNFs) are considered next generation, renewable reinforcements for sustainable, high-performance bioinspired nanocomposites uniting high stiffness, strength and toughness. However, the challenges associated with making well-defined CNF/polymer nanopaper hybrid structures with well-controlled polymer properties have so far hampered to deduce a quantitative picture of the mechanical properties space and deformation mechanisms, and limits the ability to tune and control the mechanical properties by rational design criteria. Here, we discuss detailed insights on how the thermo-mechanical properties of tailor-made copolymers govern the tensile properties in bioinspired CNF/polymer settings, hence at high fractions of reinforcements and under nanoconfinement conditions for the polymers. To this end, we synthesize a series of fully water-soluble and nonionic copolymers, whose glass transition temperatures (Tg) are varied from -60 to 130 °C. We demonstrate that well-defined polymer-coated core/shell nanofibrils form at intermediate stages and that well-defined nanopaper structures with tunable nanostructure arise. The systematic correlation between the thermal transitions in the (co)polymers, as well as its fraction, on the mechanical properties and deformation mechanisms of the nanocomposites is underscored by tensile tests, SEM imaging of fracture surfaces and dynamic mechanical analysis. An optimum toughness is obtained for copolymers with a Tg close to the testing temperature, where the soft phase possesses the best combination of high molecular mobility and cohesive strength. New deformation modes are activated for the toughest compositions. Our study establishes quantitative structure/property relationships in CNF/(co)polymer nanopapers and opens the design space for future, rational molecular engineering using reversible supramolecular bonds or covalent cross-linking.

  19. Phases of polymer systems in solution studied via molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Joshua Allen [Iowa State Univ., Ames, IA (United States)

    2009-05-01

    Polymers are amazingly versatile molecules with a tremendous range of applications. Our lives would be very different without them. There would be no multitudes of plastic encased electronic gizmos, no latex paint on the walls and no rubber tires, just to name a few of the many commonplace polymer materials. In fact, life as we know it wouldn’t exist without polymers as two of the most essential types of molecules central to cellular life, Proteins and DNA, are both polymers! [1] With their wide range of application to a variety of uses, polymers are still a very active field in basic research. Of particular current interest is the idea of combining polymers with inorganic particles to form novel composite materials. [2] As computers are becoming faster, they are becoming all the more powerful tools for modeling and simulating real systems. With recent advances in computing on graphics processing units (GPUs) [3–7], questions can now be answered via simulation that could not even be asked before. This thesis focuses on the use of computer simulations to model novel polymerinorganic composite systems in order to predict what possible phases can form and under what conditions. The goal is to provide some direction for future experiments and to gain a deeper understanding of the fundamental physics involved. Along the way, there are some interesting and essential side-tracks in the areas of equilibrating complicated phases and accelerating the available computer power with GPU computing, both of which are necessary steps to enable the study of polymer nanocomposites.

  20. The Role of Polymer Fractionation in Energetic Losses and Charge Carrier Lifetimes of Polymer: Fullerene Solar Cells

    KAUST Repository

    Baran, Derya

    2015-08-10

    Non-radiative recombination reduces the open-circuit voltage relative to its theoretical limit and leads to reduced luminescence emission at a given excitation. Therefore it is possible to correlate changes in luminescence emission with changes in open-circuit voltage and in the charge carrier lifetime. Here we use luminescence studies combined with transient photovoltage and differential charging analyses to study the effect of polymer fractionation in indacenoedithiophene-co-benzothiadiazole (IDTBT):fullerene solar cells. In this system, polymer fractionation increases electroluminescence and reduces non-radiative recombination. High molecular weight and fractionated IDTBT polymers exhibit higher carrier lifetime-mobility product compared to their non-fractionated analogues, resulting in improved solar cell performance.

  1. Stochastic entangled chain dynamics of dense polymer solutions.

    Science.gov (United States)

    Kivotides, Demosthenes; Wilkin, S Louise; Theofanous, Theo G

    2010-10-14

    We propose an adjustable-parameter-free, entangled chain dynamics model of dense polymer solutions. The model includes the self-consistent dynamics of molecular chains and solvent by describing the former via coarse-grained polymer dynamics that incorporate hydrodynamic interaction effects, and the latter via the forced Stokes equation. Real chain elasticity is modeled via the inclusion of a Pincus regime in the polymer's force-extension curve. Excluded volume effects are taken into account via the combined action of coarse-grained intermolecular potentials and explicit geometric tracking of chain entanglements. We demonstrate that entanglements are responsible for a new (compared to phantom chain dynamics), slow relaxation mode whose characteristic time scale agrees very well with experiment. Similarly good agreement between theory and experiment is also obtained for the equilibrium chain size. We develop methods for the solution of the model in periodic flow domains and apply them to the computation of entangled polymer solutions in equilibrium. We show that the number of entanglements Π agrees well with the number of entanglements expected on the basis of tube theory, satisfactorily reproducing the latter's scaling of Π with the polymer volume fraction φ. Our model predicts diminishing chain size with concentration, thus vindicating Flory's suggestion of excluded volume effects screening in dense solutions. The predicted scaling of chain size with φ is consistent with the heuristic, Flory theory based value.

  2. Multifunctional hyperbranched glycoconjugated polymers based on natural aminoglycosides.

    Science.gov (United States)

    Chen, Mingsheng; Hu, Mei; Wang, Dali; Wang, Guojian; Zhu, Xinyuan; Yan, Deyue; Sun, Jian

    2012-06-20

    Multifunctional gene vectors with high transfection, low cytotoxicity, and good antitumor and antibacterial activities were prepared from natural aminoglycosides. Through the Michael-addition polymerization of gentamycin and N,N'-methylenebisacrylamide, cationic hyperbranched glycoconjugated polymers were synthesized, and their physical and chemical properties were analyzed by FTIR, (1)H NMR, (13)C NMR, GPC, ζ-potential, and acid-base titration techniques. The cytotoxicity of these hyperbranched glycoconjugated polycations was low because of the hydrolysis of degradable glycosidic and amide linkages in acid conditions. Owing to the presence of various primary, secondary, and tertiary amines in the polymers, hyperbranched glycoconjugated polymers showed high buffering capacity and strong DNA condensation ability, resulting in the high transfection efficiency. In the meantime, due to the introduction of natural aminoglycosides into the polymeric backbone, the resultant hyperbranched glycoconjugated polymers inhibited the growth of cancer cells and bacteria efficiently. Combining the gene transfection, antitumor, and antibacterial abilities together, the multifunctional hyperbranched glycoconjugated polymers based on natural aminoglycosides may play an important role in protecting cancer patients from bacterial infections.

  3. Physical stability of API/polymer-blend amorphous solid dispersions.

    Science.gov (United States)

    Lehmkemper, Kristin; Kyeremateng, Samuel O; Bartels, Mareike; Degenhardt, Matthias; Sadowski, Gabriele

    2018-03-01

    The preparation of amorphous solid dispersions (ASDs) is a well-established strategy for formulating active pharmaceutical ingredients by embedding them in excipients, usually amorphous polymers. Different polymers can be combined for designing ASDs with desired properties like an optimized dissolution behavior. One important criterion for the development of ASD compositions is the physical stability. In this work, the physical stability of API/polymer-blend ASDs was investigated by thermodynamic modeling and stability studies. Amorphous naproxen (NAP) and acetaminophen (APAP) were embedded in blends of hydroxypropyl methylcellulose acetate succinate (HPMCAS) and either poly(vinylpyrrolidone) (PVP) or poly(vinylpyrrolidone-co-vinyl acetate) (PVPVA64). Parameters for modeling the API solubility in the blends and the glass-transition temperature curves of the water-free systems with Perturbed-Chain Statistical Associating Fluid Theory and Kwei equation, respectively, were correlated to experimental data. The phase behavior for standardized storage conditions (0%, 60% and 75% relative humidity (RH)) was predicted and compared to six months-long stability studies. According to modeling and experimental results, the physical stability was reduced with increasing HPMCAS content and increasing RH. This trend was observed for all investigated systems, with both APIs (NAP and APAP) and both polymer blends (PVP/HPMCAS and PVPVA64/HPMCAS). PC-SAFT and the Kwei equation turned out to be suitable tools for modeling and predicting the physical stability of the investigated API/polymer-blends ASDs. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Polymer coated mucoadhesive liposomes intended for the management of xerostomia.

    Science.gov (United States)

    Adamczak, Małgorzata I; Martinsen, Ørjan G; Smistad, Gro; Hiorth, Marianne

    2017-07-15

    The aim of this work was to prepare and test different pharmaceutical formulations in respect of their potential in relieving dry mouth symptom. Since many of the products available on the market provide only temporary relief to the patients, there is need for new formulations able to retain on the oral mucosa. The prolonged moisture protection could be achieved by combining mucoadhesive materials, such as polymers containing hydrogen bonding groups, with vesicles capable of releasing hydration medium from the inner compartment. In this study three different types of liposomes (positively, negatively and neutrally charged) were coated with five different types of polymers: low-methoxylated pectin (LM-pectin), high-methoxylated pectin (HM-pectin), alginate, chitosan and hydrophobically modified ethyl hydroxyethyl cellulose (HM-EHEC). The particle size and the zeta potential of the obtained carriers were tested by measuring dynamic light scattering (DLS) and electrophoretic mobility. Later on, selected positively charged liposomes were deposited on a negatively charged mica surface and depicted by atomic force microscopy (AFM). The water sorption properties of polymers, uncoated liposomes and polymer-coated liposomes were studied by the means of dynamic vapor sorption (DVS). The experiments were performed within the relative humidity range RH=95-0-95%, at 35°C. It was found that coating the liposomes with polymers significantly increased the water sorption capacity of the formulations, making them an attractive choice for hydration of the oral mucosa. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Nano-Star-Shaped Polymers for Drug Delivery Applications.

    Science.gov (United States)

    Yang, Da-Peng; Oo, Ma Nwe Nwe Linn; Deen, Gulam Roshan; Li, Zibiao; Loh, Xian Jun

    2017-11-01

    With the advancement of polymer engineering, complex star-shaped polymer architectures can be synthesized with ease, bringing about a host of unique properties and applications. The polymer arms can be functionalized with different chemical groups to fine-tune the response behavior or be endowed with targeting ligands or stimuli responsive moieties to control its physicochemical behavior and self-organization in solution. Rheological properties of these solutions can be modulated, which also facilitates the control of the diffusion of the drug from these star-based nanocarriers. However, these star-shaped polymers designed for drug delivery are still in a very early stage of development. Due to the sheer diversity of macromolecules that can take on the star architectures and the various combinations of functional groups that can be cross-linked together, there remain many structure-property relationships which have yet to be fully established. This review aims to provide an introductory perspective on the basic synthetic methods of star-shaped polymers, the properties which can be controlled by the unique architecture, and also recent advances in drug delivery applications related to these star candidates. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. EFRC: Polymer-Based Materials for Harvesting Solar Energy (stimulus)"

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Thomas P. [Univ. of Massachusetts, Amherst, MA (United States)

    2016-12-08

    The University of Massachusetts Amherst is proposing an Energy Frontier Research Center (EFRC) on Polymer-Based Materials for Harvesting Solar Energy that will integrate the widely complementary experimental and theoretical expertise of 23 faculty at UMass-Amherst Departments with researchers from the University of Massachusetts Lowell, University of Pittsburgh, the Pennsylvania State University and Konarka Technologies, Inc. Collaborative efforts with researchers at the Oak Ridge National Laboratory, the University of Bayreuth, Seoul National University and Tohoku University will complement and expand the experimental efforts in the EFRC. Our primary research aim of this EFRC is the development of hybrid polymer-based devices with efficiencies more than twice the current organic-based devices, by combining expertise in the design and synthesis of photoactive polymers, the control and guidance of polymer-based assemblies, leadership in nanostructured polymeric materials, and the theory and modeling of non-equilibrium structures. A primary goal of this EFRC is to improve the collection and conversion efficiency of a broader spectral range of solar energy using the directed self-assembly of polymer-based materials so as to optimize the design and fabrication of inexpensive devices.

  7. Applications of polymers for biomolecule immobilization in electrochemical biosensors

    International Nuclear Information System (INIS)

    Teles, F.R.R.; Fonseca, L.P.

    2008-01-01

    Polymers are becoming inseparable from biomolecule immobilization strategies and biosensor platforms. Their original role as electrical insulators has been progressively substituted by their electrical conductive abilities, which opens a new and broad scope of applications. In addition, recent advances in diagnostic chips and microfluidic systems, together with the requirements of mass-production technologies, have raised the need to replace glass by polymeric materials, which are more suitable for production through simple manufacturing processes. Conducting polymers (CPs), in particular, are especially amenable for electrochemical biosensor development for providing biomolecule immobilization and for rapid electron transfer. It is expected that the combination of known polymer substrates, but also new transducing and biocompatible interfaces, with nanobiotechnological structures, like nanoparticles, carbon nanotubes (CNTs) and nanoengineered 'smart' polymers, may generate composites with new and interesting properties, providing higher sensitivity and stability of the immobilized molecules, thus constituting the basis for new and improved analytical devices for biomedical and other applications. This review covers the state-of-the-art and main novelties about the use of polymers for immobilization of biomolecules in electrochemical biosensor platforms

  8. Culture experiments on conductive polymers

    International Nuclear Information System (INIS)

    Onoda, Mitsuyoshi

    2012-01-01

    Fibroblast L929 and myoblast C2C12 cells of the mouse connective tissue origin were sown on the surface of conductive polymer films (polypyrrole, PPy and poly(3,4-ethylenedioxythiophene), PEDOT) in the cell culture medium, and the proliferative process of these cells was observed. Without changing the form, fibroblast L929 and myoblast C2C12 cells were observed to proliferate almost similarly to the cell which cultured on a dish on the market and to maintain compatibility. In other word, it has been understood these two kinds of conductive polymers used in this study, the PEDOT films maintain the secretion function of the cell cultured on the surface of these polymers. Therefore, the PPy- and the PEDOT-coated electrode suggested the possibility usable as a nerve stimulation electrode with biocompatibility, because these polymers were effective to culture the cell.

  9. Polyphosphazine-based polymer materials

    Science.gov (United States)

    Fox, Robert V.; Avci, Recep; Groenewold, Gary S.

    2010-05-25

    Methods of removing contaminant matter from porous materials include applying a polymer material to a contaminated surface, irradiating the contaminated surface to cause redistribution of contaminant matter, and removing at least a portion of the polymer material from the surface. Systems for decontaminating a contaminated structure comprising porous material include a radiation device configured to emit electromagnetic radiation toward a surface of a structure, and at least one spray device configured to apply a capture material onto the surface of the structure. Polymer materials that can be used in such methods and systems include polyphosphazine-based polymer materials having polyphosphazine backbone segments and side chain groups that include selected functional groups. The selected functional groups may include iminos, oximes, carboxylates, sulfonates, .beta.-diketones, phosphine sulfides, phosphates, phosphites, phosphonates, phosphinates, phosphine oxides, monothio phosphinic acids, and dithio phosphinic acids.

  10. NMR Studies of Polymer Nanocomposites

    National Research Council Canada - National Science Library

    Greenbaum, Steve

    2001-01-01

    ... of their kind ever published. Standard ambient pressure results for lithium ion conducting polymer electrolytes containing nanoscopic silica are included, as well as the description of a novel scheme to produce highly conducting...

  11. Polymer electronic devices and materials.

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, William Kent; Baca, Paul Martin; Dirk, Shawn M.; Anderson, G. Ronald; Wheeler, David Roger

    2006-01-01

    Polymer electronic devices and materials have vast potential for future microsystems and could have many advantages over conventional inorganic semiconductor based systems, including ease of manufacturing, cost, weight, flexibility, and the ability to integrate a wide variety of functions on a single platform. Starting materials and substrates are relatively inexpensive and amenable to mass manufacturing methods. This project attempted to plant the seeds for a new core competency in polymer electronics at Sandia National Laboratories. As part of this effort a wide variety of polymer components and devices, ranging from simple resistors to infrared sensitive devices, were fabricated and characterized. Ink jet printing capabilities were established. In addition to promising results on prototype devices the project highlighted the directions where future investments must be made to establish a viable polymer electronics competency.

  12. Sonochemical Preparation of Polymer Nanocomposites

    Directory of Open Access Journals (Sweden)

    Hyoung Jin Choi

    2009-06-01

    Full Text Available Thisreview covers sonochemical fabrication of polymer nanocomposites. In addition to its application to the synthesis of various polymeric systems, due to its powerful efficiency, sonochemistry has been widely used not only as the assistant of dispersion for nanomaterials such as carbon nanotubes (CNT and organophillic clay, but also as a special initiator to enhance polymerization for fabrication of polymer nanocomposites with CNT and metallic nanoparticles. Recent developments in the preparation of multi-walled carbon nanotube/polymer nanocomposites with polystyrene and PMMA, magnetic particle/CNT composites and polymer/clay nanocomposites along with their physical characteristics and potential engineering applications will be introduced. Physical characterizations include morphological, thermal, and rheological properties under either an applied electric or magnetic field.

  13. Photosensitized oxidation of unsaturated polymers

    Science.gov (United States)

    Golub, M. A.

    1979-01-01

    The photosensitized oxidation or singlet oxygenation of unsaturated hydrocarbon polymers and of their model compounds was reviewed. Emphasis was on cis and trans forms of 1,4-polyisoprene, 1,4-polybutadiene and 1,2-poly(1,4-hexadiene), and on 1,4-poly(2,3-dimethyl-1,3-butadiene). The microstructural changes which occur in these polymers on reaction with O2-1 in solution were investigated by infrared H-1 and C-13 NMR spectroscopy. The polymers were shown to yield allylic hydroperoxides with shifted double bonds according to the ene mechanism established for simple olefins. The photosensitized oxidation of the above unsaturated polymer exhibited zero order kinetics, the relative rates paralleling the reactivities of the corresponding simple olefins towards O2-1.

  14. All-Polymer Electrochemical Sensors

    DEFF Research Database (Denmark)

    Kafka, Jan Robert

    This thesis presents fabrication strategies to produce different types of all-polymer electrochemical sensors based on electrodes made of the highly conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT). Three different systems are presented, fabricated either by using microdrilling or by hot......-controlled microdrilling was applied to drill through an insulating polymer, covering a conductive layer of PEDOT. The sudden drop in electrical resistance between the metal drill and the PEDOT layer upon physical contact was employed as stop criterion for the drilling process. Arrays of 3x 3 microelectrodes of diameter...... electrode configurations showed that the conducting polymer electrodes approach the steady state currents predicted from modeling, but at a much slower rate than expected. This wasshown to be caused by the use of electro active PEDOT electrodes. Subtraction of the latter contribution gave an approach...

  15. Layered plasma polymer composite membranes

    Science.gov (United States)

    Babcock, Walter C.

    1994-01-01

    Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is .gtoreq.2 and is the number of selective layers.

  16. Solid Polymer Nanocomposite Battery Electrolyte

    Data.gov (United States)

    National Aeronautics and Space Administration — Incorporate nano-graphene and nano-metal oxides in polymer electrolyte to enhance ionic conductivity; incorporate ionic liquid to improve ion transport properties in...

  17. Finely divided, irradiated tetrafluorethylene polymers

    International Nuclear Information System (INIS)

    Brown, M.T.; Rodway, W.G.

    1977-01-01

    Dry non-sticky fine lubricant powders are made by γ-irradiation of unsintered coagulated dispersion grade tetrafluoroethylene polymers. These powders may also be dispersed in an organic medium for lubricating purposes

  18. Applications of synthetic polymers in clinical medicine

    OpenAIRE

    Maitz, M.F.

    2015-01-01

    Multiple biological, synthetic and hybrid polymers are used for multiple medical applications. A wide range of different polymers is available, and they have further the advantage to be tunable in physical, chemical and biological properties in a wide range to match the requirements of specific applications. This review gives a brief overview about the introduction and developments of polymers in medicine in general, addressing first stable polymers, then polymers with degradability as a firs...

  19. Water Soluble Polymers for Pharmaceutical Applications

    OpenAIRE

    Veeran Gowda Kadajji; Guru V. Betageri

    2011-01-01

    Advances in polymer science have led to the development of novel drug delivery systems. Some polymers are obtained from natural resources and then chemically modified for various applications, while others are chemically synthesized and used. A large number of natural and synthetic polymers are available. In the present paper, only water soluble polymers are described. They have been explained in two categories (1) synthetic and (2) natural. Drug polymer conjugates, block copolymers, hydrogel...

  20. News from Online: Industrial Chemicals and Polymers

    Science.gov (United States)

    Sweeney Judd, Carolyn

    1999-02-01

    of the American Chemical Society Divisions of Polymer Chemistry and Polymeric Materials: Science and Engineering and General Electric Corporation. The POLYED site, http:/ /chemdept.uwsp.edu/polyed/index.htm, is hosted by the University of Wisconsin at Stevens Point. This National Center for Polymer Education is another good place to go for information. More education is available at the Ziegler Research Group Home Page at http://www.chem.ucalgary.ca/groups/ziegler/index.html . Go to Metallocene as Olefin Polymerization Catalysis: An Introduction ( http://www.chem.ucalgary.ca/groups/ziegler/met_intro.html ) for historical accounts of metallocene and Ziegler-Natta catalysts. Movies are available here too. This Canadian site is well-documented and educational. Back at the University of Wisconsin-Madison, The Why Files site at http://whyfiles.news.wisc.edu helps bring important chemical and technology news to the public. Go to the archived files of October 1997 ( http://whyfiles.news.wisc.edu/shorties/catalyst.html ) to find information about the importance of low-temperature metallocene catalysts. The Why Files received funding from the National Science Foundation. Go here for science information in an easy-to-read format. One of the driving forces toward better catalysis is the attempt to reach 100% product, combining efficiency with lowered pollution. Companies can look to the Environmental Protection Agency for information: Environsense at http://es.epa.gov/ is pledged to offer "Common Sense Solutions to Environmental Problems". So where can we get these polymers? The American Chemical Society can help. Go to Chemcylopedia at http://pubs.acs.org/chemcy99/ for great information. Both purchasers and users of chemicals can benefit from this site. Searches can be made on the chemical or on the supplier. Information provided includes CAS Registry Numbers and special shipping requirements as well as potential applications. Do you remember that we started with paper? Let

  1. Characterization of Tantalum Polymer Capacitors

    Science.gov (United States)

    Spence, Penelope

    2012-01-01

    Overview Reviewed data Caution must be taken when accelerating test conditions Data not useful to establish an acceleration model Introduction of new failure mechanism skewing results Evidence of Anti-Wear-Out De-doping of polymer Decreased capacitance Increased ESR Not dielectric breakdown Needs further investigation Further investigation into tantalum polymer capacitor technology Promising acceleration model for Manufacturer A Possibility for use in high-reliability space applications with suitable voltage derating.

  2. Nanoporous polymer liquid core waveguides

    DEFF Research Database (Denmark)

    Gopalakrishnan, Nimi; Christiansen, Mads Brøkner; Ndoni, Sokol

    2010-01-01

    We demonstrate liquid core waveguides defined by UV to enable selective water infiltration in nanoporous polymers, creating an effective refractive index shift Δn=0.13. The mode confinement and propagation loss in these waveguides are presented.......We demonstrate liquid core waveguides defined by UV to enable selective water infiltration in nanoporous polymers, creating an effective refractive index shift Δn=0.13. The mode confinement and propagation loss in these waveguides are presented....

  3. Polymer Claw: Instant Underwater Adhesive

    Science.gov (United States)

    2012-09-24

    glycerol is a well-known hygroscopic liquid and lubricant. In the Polymer Claw Progress Report -4- 9/24/12 The Johns Hopkins University Applied Physics...the Polymer Claw adhesive partially solidified, while commercial adhesives were completely liquid after one hour. However, the curing rate was...is not valid for partial liquid adhesives, we will only test at later times, noting the minimum time for which the glass slides break. The time to

  4. Radiation processing of natural polymer

    International Nuclear Information System (INIS)

    Khairul Zaman; Kamaruddin Hashim; Zulkafli Ghazali; Mohd Hilmi Mahmood; Jamaliah Sharif

    2006-01-01

    Radiation processing of natural polymer has been the subject of interest of countries in this region in the past 5 ∼ 7 years. Although some of the output of the research have been commercialized in particular for the applications in the agriculture and healthcare sectors, the potential applications of radiation processing of natural polymers in the medical sector are yet to be fully understood and developed. (author)

  5. UV-cured polymer optics

    Science.gov (United States)

    Piñón, Victor; Santiago, Freddie; Vogelsberg, Ashten; Davenport, Amelia; Cramer, Neil

    2017-10-01

    Although many optical-quality glass materials are available for use in optical systems, the range of polymeric materials is limited. Polymeric materials have some advantages over glass when it comes to large-scale manufacturing and production. In smaller scale systems, they offer a reduction in weight when compared to glass counterparts. This is especially important when designing optical systems meant to be carried by hand. We aimed to expand the availability of polymeric materials by exploring both crown-like and flint-like polymers. In addition, rapid and facile production was also a goal. By using UV-cured thiolene-based polymers, we were able to produce optical materials within seconds. This enabled the rapid screening of a variety of polymers from which we down-selected to produce optical flats and lenses. We will discuss problems with production and mitigation strategies in using UV-cured polymers for optical components. Using UV-cured polymers present a different set of problems than traditional injection-molded polymers, and these issues are discussed in detail. Using these produced optics, we integrated them into a modified direct view optical system, with the end goal being the development of drop-in replacements for glass components. This optical production strategy shows promise for use in lab-scale systems, where low-cost methods and flexibility are of paramount importance.

  6. Making of polymer fine particles

    International Nuclear Information System (INIS)

    Ono, Isamu

    1990-01-01

    The polymer particles having spherical shape and uniform grain diameter are applied to various fields such as powder coating, cosmetics, medicines, foods and others. These polymer fine particles are synthesized from monomers at the temperature higher than room temperature by emulsifying polymerization, suspension polymerization or dispersion polymerization, using polymerization initiator. The diameter of such synthesized fine particles is from 0.1 to 10 μm. In this study, the method of synthesizing polymer fine particles by dispersion radiation polymerization process without using polymerization initiator and emulsifying agent was examined. Monomers are dissolved in the solvent, in which monomers are soluble but polymers are insoluble, and by polymerizing with radiation, polymer fine particles are synthesized. It has the merits that additive agents are not contained, and the synthesis can be done at room temperature. The method and the results are reported. As the mechanism of forming fine particles, the reaction of beginning polymerization and the precipitation of polymers are explained. By controlling reaction temperature and monomer concentration, particle diameter can be adjusted. The monomers used were styrene, methyl metacrylate and vinyl acetate. (K.I.)

  7. Polymer reinforcement of cement systems

    International Nuclear Information System (INIS)

    Swamy, R.N.

    1979-01-01

    In the last couple of decades several cement- and concrete-based composites have come into prominence. Of these, cement-polymer composites, like cement-fibre composites, have been recognised as very promising, and considerable research and development on their properties, fabrication methods and application are in progress. Of the three types of concrete materials which incorporate polymers to form composites, polymer impregnated concrete forms a major development in which hardened concrete is impregnated with a liquid monomer which is subsequently polymerized to form a rigid polymer network in the pores of the parent material. In this first part of the extensive review of the polymer reinforcement of cement systems, the process technology of the various monomer impregnation techniques and the properties of the impregnated composite are assessed critically. It is shown that the high durability and superior performance of polymer impregnated concrete can provide an economic and competitive alternative in in situ strengthening, and in other areas where conventional concrete can only at best provide adequate performance. The review includes a section on radiation-induced polymerization. (author)

  8. Changes in molecular structure and properties of irradiated polymers of different compositions - ESR and NMR study

    International Nuclear Information System (INIS)

    Carswell-Pomerantz, T.; Babanalbandi, A.; Dong, L.; Hill, D.J.T.; Perera, M.C.S.; Pomery, P.J.; Saadat, G.; Whittaker, A.K.

    1999-01-01

    Investigations of molecular structural changes in polymers during exposure to high energy radiation is the long term interest of the Polymer Materials and Radiation Group at the University of Queensland. Recently, the group had looked at a range of polymers including natural and synthetic rubbers, methacrylates and polyesters. The objective of the work has been to investigate the relationships between polymer structure and sensitivity towards high energy radiation, including gamma radiation. This report will focus on the Electron Spin Resonance (ESR) and Nuclear Magnetic Resonance (NMR) studies of the effects of gamma irradiation on these polymers. Other methods such as Gas Chromatography (GC), Gel Permeation Chromatography (GPC), Fourier Transformed Infra Red (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and Dynamic Mechanical Analysis (DMA) have also been used as these methods combine with ESR and NMR, to provide a more complete picture of the mechanism of the structural changes. (author)

  9. Fundamental Costs in the Production and Destruction of Persistent Polymer Copies

    Science.gov (United States)

    Ouldridge, Thomas E.; Rein ten Wolde, Pieter

    2017-04-01

    Producing a polymer copy of a polymer template is central to biology, and effective copies must persist after template separation. We show that this separation has three fundamental thermodynamic effects. First, polymer-template interactions do not contribute to overall reaction thermodynamics and hence cannot drive the process. Second, the equilibrium state of the copied polymer is template independent and so additional work is required to provide specificity. Finally, the mixing of copies from distinct templates makes correlations between template and copy sequences unexploitable, combining with copying inaccuracy to reduce the free energy stored in a polymer ensemble. These basic principles set limits on the underlying costs and resource requirements, and suggest design principles, for autonomous copying and replication in biological and synthetic systems.

  10. Multicomponent semiconducting polymer systems with low crystallization-induced percolation threshold

    DEFF Research Database (Denmark)

    Goffri, S.; Müller, C.; Stingelin-Stutzmann, N.

    2006-01-01

    with the excellent mechanical properties of certain commodity polymers. Here we investigate bicomponent blends comprising semicrystalline regioregular poly(3-hexylthiophene) and selected semicrystalline commodity polymers, and show that, owing to a highly favourable, crystallization-induced phase segregation......–crystalline/semiconducting–insulating multicomponent systems offer expanded flexibility for realizing high-performance semiconducting architectures at drastically reduced materials cost with improved mechanical properties and environmental stability, without the need to design all performance requirements into the active semiconducting polymer......Blends and other multicomponent systems are used in various polymer applications to meet multiple requirements that cannot be fulfilled by a single material1, 2, 3. In polymer optoelectronic devices it is often desirable to combine the semiconducting properties of the conjugated species...

  11. POLYMER COMPOSITE FILMS WITH SIZE-SELECTED METAL NANOPARTICLES FABRICATED BY CLUSTER BEAM TECHNIQUE

    DEFF Research Database (Denmark)

    Ceynowa, F. A.; Chirumamilla, Manohar; Popok, Vladimir

    2017-01-01

    Formation of polymer films with size-selected silver and copper nanoparticles (NPs) is studied. Polymers are prepared by spin coating while NPs are fabricated and deposited utilizing a magnetron sputtering cluster apparatus. The particle embedding into the films is provided by thermal annealing...... after the deposition. The degree of immersion can be controlled by the annealing temperature and time. Together with control of cluster coverage the described approach represents an efficient method for the synthesis of thin polymer composite layers with either partially or fully embedded metal NPs....... Combining electron beam lithography, cluster beam deposition and thermal annealing allows to form ordered arrays of metal NPs on polymer films. Plasticity and flexibility of polymer host and specific properties added by coinage metal NPs open a way for different applications of such composite materials...

  12. Suspensions of polymer-grafted nanoparticles with added polymers—Structure and effective pair-interactions

    Science.gov (United States)

    Chandran, Sivasurender; Saw, Shibu; Kandar, A. K.; Dasgupta, C.; Sprung, M.; Basu, J. K.

    2015-08-01

    We present the results of combined experimental and theoretical (molecular dynamics simulations and integral equation theory) studies of the structure and effective interactions of suspensions of polymer grafted nanoparticles (PGNPs) in the presence of linear polymers. Due to the absence of systematic experimental and theoretical studies of PGNPs, it is widely believed that the structure and effective interactions in such binary mixtures would be very similar to those of an analogous soft colloidal material—star polymers. In our study, polystyrene-grafted gold nanoparticles with functionality f = 70 were mixed with linear polystyrene (PS) of two different molecular weights for obtaining two PGNP:PS size ratios, ξ = 0.14 and 2.76 (where, ξ = Mg/Mm, Mg and Mm being the molecular weights of grafting and matrix polymers, respectively). The experimental structure factor of PGNPs could be modeled with an effective potential (Model-X), which has been found to be widely applicable for star polymers. Similarly, the structure factor of the blends with ξ = 0.14 could be modeled reasonably well, while the structure of blends with ξ = 2.76 could not be captured, especially for high density of added polymers. A model (Model-Y) for effective interactions between PGNPs in a melt of matrix polymers also failed to provide good agreement with the experimental data for samples with ξ = 2.76 and high density of added polymers. We tentatively attribute this anomaly in modeling the structure factor of blends with ξ = 2.76 to the questionable assumption of Model-X in describing the added polymers as star polymers with functionality 2, which gets manifested in both polymer-polymer and polymer-PGNP interactions especially at higher fractions of added polymers. The failure of Model-Y may be due to the neglect of possible many-body interactions among PGNPs mediated by matrix polymers when the fraction of added polymers is high. These observations point to the need for a new framework

  13. Development of polymer films by the coalescence of polymer particles in powdered and aqueous polymer-modified mortars

    International Nuclear Information System (INIS)

    Afridi, M.U.K.; Ohama, Y.; Demura, K.; Iqbal, M.Z.

    2003-01-01

    This paper evaluates and compares the coalescence of polymer particles (continuous polymer films formation) in powdered polymer-modified mortars (PPMMs) and aqueous polymer-modified mortars (APMMs). Polymer-modified mortars (PMMs) using various redispersible polymer powders (powdered cement modifiers) and polymer dispersions (aqueous cement modifiers) were prepared by varying the polymer-cement ratio (P/C) and were tested for the characterization of polymer films using a scanning electron microscope (SEM) after curing for 28 days. It is concluded from the test results that mortar constituents of unmodified mortar (UMM) are loosely joined with each other due to the absence of polymer films, thus having a structure with comparatively lower mechanical and durability characteristics. By contrast, mortar constituents in PPMMs and APMMs are compactly joined with each other due to the presence of interweaving polymer films, thereby forming a monolithic structure with improved mechanical and durability characteristics. However, the results make obvious the poor coalescence of polymer particles or development of inferior quality polymers films in PPMMs as compared to that observed in APMMs. Moreover, PPMMs show less uniform distribution of polymer films as compared to that in APMMs. Different powdered cement modifiers have different film-forming capabilities. However, such difference is hardly recognized in aqueous cement modifiers. The polymer films in PPMMs and APMMs may acquire different structures. They may appear as mesh-like, thread-like, rugged, dense or fibrous with fine or rough surfaces. Development of coherent polymer films is not well pronounced at a P/C of 5% in PPMMs, whereas sometimes coherent polymer films are observed at a P/C of 5% in APMMs. At a P/C of 10% or more, fully developed, coherent polymer films are observed in both PPMMs and APMMs

  14. Polymer Nanocomposites with Prescribed Morphology: Going Beyond Nanoparticle-Filled Polymers (Preprint)

    National Research Council Canada - National Science Library

    Vaia, Richard A; Maguire, John F

    2006-01-01

    Polymer nanocomposites (PNCs), i.e., nanoparticles (spheres, rods, and plates) dispersed in a polymer matrix, have garnered substantial academic and industrial interest since their inception, ca. 1990...

  15. Dihydroxybenzene/benzoquinone-containing polymers: organic redox polymers

    Energy Technology Data Exchange (ETDEWEB)

    Moulay, S. [Universite de Blida, Lab. de Chimie-Physique Macromoleculaire, Institut de Chimie Industrielle (Algeria)

    2000-08-01

    Polymers containing hydroquinone, catechol or their corresponding benzoquinones are a special class of redox polymers. Three pathways of their syntheses are possible: condensation polymerization of suitable monomers, addition polymerization of vinyl monomers containing redox moiety, and chemical attachment of redox unit onto pre-made polymeric matrix. A range of functionalized matrices have been employed such as polyethers, polyesters, polycarbonates, polyurethanes, polyamides and others. Protection of their phenolic functionality has conducted to chemically interesting redox polymer precursors. The presence of a redox moiety coupled with the extant functionalization of the polymer matrix makes the materials very valuable, of wide properties and consequently of vast applicability. For instance, in the oil field, some polymers such as carboxy-methyl-cellulose (CMC) are often applied as to bring about a viscosity improvement and therefore to facilitate the oil drilling. In this regard, Patel evaluated sulfo-alkylated polymeric catechol, namely sulfo-methylated and sulfo-ethylated resins. Indeed, polymeric catechol chemically modified as such exhibited a marked ability to control the viscosity, the gel strength, as well as the filtrate loss of aqueous oil drilling fluids.

  16. A salt water battery with high stability and charging rates made from solution processed conjugated polymers with polar side chains

    OpenAIRE

    Moia, Davide; Giovannitti, Alexander; Szumska, Anna A.; Schnurr, Martin; Rezasoltani, Elham; Maria, Iuliana P.; Barnes, Piers R. F.; McCulloch, Iain; Nelson, Jenny

    2017-01-01

    We report a neutral salt water based battery which uses p-type and n-type solution processed polymer films as the cathode and the anode of the cell. The specific capacity of the electrodes (approximately 30 mAh cm-3) is achieved via formation of bipolarons in both the p-type and n-type polymers. By engineering ethylene glycol and zwitterion based side chains attached to the polymer backbone we facilitate rapid ion transport through the non-porous polymer films. This, combined with efficient t...

  17. Nanostructured polymer membranes for proton conduction

    Science.gov (United States)

    Balsara, Nitash Pervez; Park, Moon Jeong

    2013-06-18

    Polymers having an improved ability to entrain water are characterized, in some embodiments, by unusual humidity-induced phase transitions. The described polymers (e.g., hydrophilically functionalized block copolymers) have a disordered state and one or more ordered states (e.g., a lamellar state, a gyroid state, etc.). In one aspect, the polymers are capable of undergoing a disorder-to-order transition while the polymer is exposed to an increasing temperature at a constant relative humidity. In some aspects the polymer includes a plurality of portions, wherein a first portion forms proton-conductive channels within the membrane and wherein the channels have a width of less than about 6 nm. The described polymers are capable of entraining and preserving water at high temperature and low humidity. Surprisingly, in some embodiments, the polymers are capable of entraining greater amounts of water with the increase of temperature. The polymers can be used in Polymer Electrolyte Membranes in fuel cells.

  18. Combined homicide

    Directory of Open Access Journals (Sweden)

    Slović Živana

    2017-01-01

    Full Text Available Introduction: Combined homicide is a combination of two or more different modes of killing. These homicides occur when multiple perpetrators have different mode of killing, to hide the true manner of death, or when an initially unsuccessful attack with one weapon is abandoned and changed by another mode which is more successful, or due to availability of weapons at the scene of homicide, or unexpected appearance of possible eyewitness, or else. Case report: This case report is about 65-year old woman who was found in her residence on the floor next to the bed lying on her back with two kitchen knives in her neck. Autopsy revealed an abrasion on the frontal part of the neck and a bruise of the soft tissues of the neck with a double fracture of both greater horns of the hyoid bone and a fracture of both superior horns of the thyroid cartilage. The cause of death was exsanguination into right half of the thoracic cavity from the left subclavian artery which was cut, on the spot of stab wound in the neck. Conclusion: Hemorrhage in the soft tissue near broken hyoid bone and thyroid cartilage indicate that the victim was first strangulated and then stabbed with kitchen knives. Combined homicides are caused by one or more killers in order to accelerate the killing, or to be sure to provide the fatal outcome. This case is also interesting because the killer left weapon in the victim's neck.

  19. Surface shape memory in polymers

    Science.gov (United States)

    Mather, Patrick

    2012-02-01

    Many crosslinked polymers exhibit a shape memory effect wherein a permanent shape can be prescribed during crosslinking and arbitrary temporary shapes may be set through network chain immobilization. Researchers have extensively investigated such shape memory polymers in bulk form (bars, films, foams), revealing a multitude of approaches. Applications abound for such materials and a significant fraction of the studies in this area concern application-specific characterization. Recently, we have turned our attention to surface shape memory in polymers as a means to miniaturization of the effect, largely motivated to study the interaction of biological cells with shape memory polymers. In this presentation, attention will be given to several approaches we have taken to prepare and study surface shape memory phenomenon. First, a reversible embossing study involving a glassy, crosslinked shape memory material will be presented. Here, the permanent shape was flat while the temporary state consisted of embossed parallel groves. Further the fixing mechanism was vitrification, with Tg adjusted to accommodate experiments with cells. We observed that the orientation and spreading of adherent cells could be triggered to change by the topographical switch from grooved to flat. Second, a functionally graded shape memory polymer will be presented, the grading being a variation in glass transition temperature in one direction along the length of films. Characterization of the shape fixing and recovery of such films utilized an indentation technique that, along with polarizing microscopy, allowed visualization of stress distribution in proximity to the indentations. Finally, very recent research concerning shape memory induced wrinkle formation on polymer surfaces will be presented. A transformation from smooth to wrinkled surfaces at physiological temperatures has been observed to have a dramatic effect on the behavior of adherent cells. A look to the future in research and

  20. Polymer derived ceramic composites as environmental barrier coatings on steel

    Science.gov (United States)

    Torrey, Jessica D.

    Polymer derived ceramics have shown promise as a novel way to process low-dimensional ceramics such as fibers and coatings. They offer advantages over traditional ceramic processing routes including lower pyrolysis temperatures and the ability to employ polymeric processing techniques. The main drawback to preceramic polymers is that they undergo a shrinkage during pyrolysis that can be greater than 50-volume%. One way to overcome this shrinkage is to add filler particles, usually elemental or binary metals, which will expand upon reaction with the pyrolysis atmosphere, thereby compensating for the shrinkage of the polymer. The aim of this study is to develop a polymer derived ceramic composite coating on steel as a barrier to oxidation and carburization, while concurrently gaining insight as to the fundamental mechanisms for compositional and microstructural evolution within the system. A systematic approach to selecting the preceramic polymer and expansion agents was taken. Six commercially available poly(silsesquioxane) polymers and a polysiloxane were studied. Several metals and an intermetallic were considered as potential expansion agents. The most desirable polymer/expansion agent combination was achieved with poly(hydridomethylsiloxane) as the matrix and titanium disilicide as the filler. Processing parameters have been optimized and a relationship derived to predict final coating thickness based on slurry viscosity and dip coating withdrawal speed. Microstructural analysis reveals an amorphous composite coating of oxidized filler particles in a silica matrix. A diffusion layer is visible at the coating-steel interface, indicating good bonding. The optimized coatings are ˜18mum thick, have some residual porosity and a density of 2.57g/cm3. A systematic study of the phase transformations and microstructural changes in the coating and its components during pyrolysis in air is also presented. The system evolves from a polymer filled with a binary metal at