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Hybrid Polymers (hybrid + polymer)
Selected AbstractsNovel Fluorinated Hybrid Polymer by Radical Polyaddition of Bis(, -trifluoromethyl- ,,, -difluorovinyl) Terephthalate onto DialkoxydialkylsilanesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 4 2003Article first published online: 25 MAR 200 No abstract is available for this article. [source] Direct ,-Hydroxylation of Ketones Catalyzed by Organic,Inorganic Hybrid Polymer.CHEMINFORM, Issue 9 2007Takayoshi Arai Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Lithium Ion Motion in a Hybrid Polymer: Confirmation of a Decoupled PolyelectrolyteCHEMPHYSCHEM, Issue 12 2007Flavio L. Souza Dr. Lithium ion migration pathways in a hybrid matrix, counterions, and active sites were identified and understanding gained using Fourier-Transform infrared (FTIR) spectroscopy (see image). [source] Indication of Local Phase Separation in Polyimide/Silica Hybrid Polymers,MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 16 2010Antonino Bartolotta Abstract PI/SiO2 hybrid polymers involving the in situ generation of SiO2 particles through the sol/gel route have emerged as promising materials in many fields of modern technology thanks to their unique structural characteristics. In this paper their structural and dynamic properties were investigated by FT-IR and DMTA as a function of SiO2 content. All data consistently highlight a loosening of polymeric structure due to the presence of SiO2 nanoparticles and suggest a silica-induced structural change most probably due to a sub-micrometer scale SiO2 phase separation. Our results demonstrate how the analysis of sub-glass ,-relaxation dynamics can be exploited to investigate sub-micro phase segregation in such materials. [source] HMGA1a Protein Unfolds or Refolds Synthetic DNA,Chromophore Hybrid Polymers: A Chaperone-Like BehaviorCHEMBIOCHEM, Issue 2 2008Wei Wan Abstract High group mobility protein, HMGA1a, was found to play a chaperone-like role in the folding or unfolding of hybrid polymers that contained well-defined synthetic chromophores and DNA sequences. The synthetic and biological hybrid polymers folded into hydrophobic chromophoric nanostructures in water, but existed as partially unfolded configurations in pH or salt buffers. The presence of HMGA1a induced unfolding of the hybrid DNA,chromophore polymer in pure water, whereas the protein promoted refolding of the same polymer in various pH or salt buffers. The origin of the chaperone-like properties probably comes from the ability of HMGA1a to reversibly bind both synthetic chromophores and single stranded DNA. The unfolding mechanisms and the binding stoichiometry of protein,hybrid polymers depended on the sequence of the synthetic polymers. [source] Hybrid Solar Cells from Regioregular Polythiophene and ZnO Nanoparticles,ADVANCED FUNCTIONAL MATERIALS, Issue 8 2006Abstract Blends of nanocrystalline zinc oxide nanoparticles (nc-ZnO) and regioregular poly(3-hexylthiophene) (P3HT) processed from solution have been used to construct hybrid polymer,metal oxide bulk-heterojunction solar cells. Thermal annealing of the spin-cast films significantly improves the solar-energy conversion efficiency of these hybrid solar cells to ,,0.9,%. Photoluminescence and photoinduced absorption spectroscopy demonstrate that charge-carrier generation is not quantitative, because a fraction of P3HT appears not to be in contact with or in close proximity to ZnO. The coarse morphology of the films, also identified by tapping-mode atomic force microscopy, likely limits the device performance. [source] Highly Non-Linear Quantum Dot Doped Nanocomposites for Functional Three-Dimensional Structures Generated by Two-Photon PolymerizationADVANCED MATERIALS, Issue 22 2010Baohua Jia A nanocomposite consisting of a photosensitive organic,inorganic hybrid polymer functionalized with PbS quantum dots has been developed using a sol,gel process. The uniformly dispersed nanocomposite exhibits ultrahigh third-order non-linearity (,3.2,×,10,12 cm2 W,1) because of the strong quantum confinement of small-sized and narrowly distributed quantum dots. The non-linear nanocomposite has been proven to be suitable for the fabrication of 3D micro/nano photonic devices using two-photon polymerization. The fabricated photonic crystals show stop gaps with more than 60% suppression in transmission at the telecommunications wavelength region. [source] Organic,Inorganic Hybrid Polymer-Encapsulated Magnetic Nanobead CatalystsCHEMISTRY - A EUROPEAN JOURNAL, Issue 3 2008Takayoshi Arai Prof. Abstract A new strategy for the encapsulation of magnetic nanobeads was developed by using the in situ self-assembly of an organic,inorganic hybrid polymer. The hybrid polymer of {[Cu(bpy)(BF4)2(H2O)2](bpy)}n (bpy=4,4,-bipyridine) was constructed on the surface of amino-functionalized magnetic beads and the resulting hybrid-polymer-encapsulated beads were utilized as catalysts for the oxidation of silyl enolates to provide the corresponding ,-hydroxy carbonyl compounds in high yield. After the completion of the reaction, the catalyst was readily recovered by magnetic separation and the recovered catalyst could be reused several times. Because the current method did not require complicated procedures for incorporating the catalyst onto the magnetic beads, the preparation and the application of various other types of organic,inorganic hybrid-polymer-coated magnetic beads could be possible. [source] Solid-phase synthesis of C -terminally modified peptidesJOURNAL OF PEPTIDE SCIENCE, Issue 11 2006Hefziba T. Ten Brink Abstract In this paper, a straightforward and generic protocol is presented to label the C -terminus of a peptide with any desired moiety that is functionalized with a primary amine. Amine-functional molecules included are polymers (useful for hybrid polymers), long alkyl chains (used in peptide amphiphiles and stabilization of peptides), propargyl amine and azido propyl-amine (desirable for ,click' chemistry), dansyl amine (fluorescent labeling of peptides) and crown ethers (peptide switches/hybrids). In the first part of the procedure, the primary amine is attached to an aldehyde-functional resin via reductive amination. To the secondary amine that is produced, an amino acid sequence is coupled via a standard solid-phase peptide synthesis protocol. Since one procedure can be applied for any given amine-functional moiety, a robust method for C -terminal peptide labeling is obtained. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd. [source] Proton transportation in an organic,inorganic hybrid polymer electrolyte based on a polysiloxane/poly(allylamine) networkJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2005Ping-Lin Kuo Abstract A new class of proton-conducting polymer was developed via the sol,gel process from amino-containing organic,inorganic hybrids by the treatment of poly(allylamine) with 3-glycidoxypropyltrimethoxysilane doped with ortho -phosphoric acid. The polymer matrix contains many hydrophilic sites and consists of a double-crosslinked framework of polysiloxane and amine/epoxide. Differential scanning calorimetry results suggest that hydrogen bonding or electrostatic forces are present between H3PO4 and the amine nitrogen, resulting in an increase in the glass-transition temperature of the poly(allylamine) chain with an increasing P/N ratio. The 31P magic-angle spinning NMR spectra indicate that three types of phosphate species are involved in the proton conduction, and the motional freedom of H3PO4 is increased with increasing P/N ratios. The conductivity above 80 °C does not drop off but increases instead. Under a dry atmosphere, a high conductivity of 10,3 S/cm at temperatures up to 130 °C has been achieved. The maximum activation energy obtained at P/N = 0.5 suggests that a transition of proton-conducting behavior exits between Grotthus- and vehicle-type mechanisms. The dependence of conductivity on relative humidity (RH) above 50% is smaller for H3PO4 -doped membranes compared with H3PO4 -free ones. These hybrid polymers have characteristics of low water content (23 wt %) and high conductivity (10,2 S/cm at 95% RH), making them promising candidates as electrolytes for fuel cells. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3359,3367, 2005 [source] Indication of Local Phase Separation in Polyimide/Silica Hybrid Polymers,MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 16 2010Antonino Bartolotta Abstract PI/SiO2 hybrid polymers involving the in situ generation of SiO2 particles through the sol/gel route have emerged as promising materials in many fields of modern technology thanks to their unique structural characteristics. In this paper their structural and dynamic properties were investigated by FT-IR and DMTA as a function of SiO2 content. All data consistently highlight a loosening of polymeric structure due to the presence of SiO2 nanoparticles and suggest a silica-induced structural change most probably due to a sub-micrometer scale SiO2 phase separation. Our results demonstrate how the analysis of sub-glass ,-relaxation dynamics can be exploited to investigate sub-micro phase segregation in such materials. [source] Preparation, characterization and application of zwitterionic polymers and membranes: current developments and perspectivePOLYMER INTERNATIONAL, Issue 12 2009Fengqin Xuan Abstract Because of their unique pendant-side chain structures and excellent properties, zwitterionic polymers and membranes, especially zwitterionic hybrids, have attracted increasing interest in recent years. Presently, they can be potentially applied in such fields as nonlinear optical systems, ionic conduction, biomedical processing and chemical separation. In view of their significance to academia and industrial processes, this review gives a brief summary of current developments in the preparation, characterization and potential application of zwitterionic polymers and membranes. Novel approaches to prepare zwitterionic hybrids are highlighted. The present state and future perspective are also discussed. Hopefully, this review can promote the understanding of zwitterionic hybrid polymers and membranes. Copyright © 2009 Society of Chemical Industry [source] Hydrogels as smart biomaterialsPOLYMER INTERNATIONAL, Issue 9 2007ich Kope Abstract Hydrogels were the first biomaterials rationally designed for human use. Beginning with the pioneering work of Wichterle and Lím on three-dimensional polymers that swell in water, we review the design, synthesis, properties, and applications of hydrogels. The field of hydrogels has moved forward at a dramatic pace. The development of suitable synthetic methods encompassing traditional chemistry to molecular biology has been used in the design of hydrogels mimicking basic processes of living systems. Stimuli-sensitive hydrogels, hydrogels with controlled degradability, genetically engineered poly(amino acid) polymers reversibly self-assembling in precisely defined three-dimensional structures, and hybrid polymers composed of two distinct classes of molecules are just some examples of these exciting novel biomaterials. The biocompatibility of hydrogels and their applications from implants to nanomaterials are also reviewed. Copyright © 2007 Society of Chemical Industry [source] HMGA1a Protein Unfolds or Refolds Synthetic DNA,Chromophore Hybrid Polymers: A Chaperone-Like BehaviorCHEMBIOCHEM, Issue 2 2008Wei Wan Abstract High group mobility protein, HMGA1a, was found to play a chaperone-like role in the folding or unfolding of hybrid polymers that contained well-defined synthetic chromophores and DNA sequences. The synthetic and biological hybrid polymers folded into hydrophobic chromophoric nanostructures in water, but existed as partially unfolded configurations in pH or salt buffers. The presence of HMGA1a induced unfolding of the hybrid DNA,chromophore polymer in pure water, whereas the protein promoted refolding of the same polymer in various pH or salt buffers. The origin of the chaperone-like properties probably comes from the ability of HMGA1a to reversibly bind both synthetic chromophores and single stranded DNA. The unfolding mechanisms and the binding stoichiometry of protein,hybrid polymers depended on the sequence of the synthetic polymers. [source] | |||||||||||||||||||||||||