The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Lian-fang Feng - One of the best experts on this subject based on the ideXlab platform.
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tape extrusion of heterogeneous Polymer blends Polymer films with highly Oriented nanoribbons structural optical property and anisotropic mechanical strength
Macromolecular Materials and Engineering, 2014Co-Authors: Long Wang, Hongxia Wang, Lian-fang FengAbstract:Highly Oriented Polymer nanoribbons are prepared by tape extrusion of a phase-separated Polymer blend into thin film and by subsequently dissolving the continuous Polymer phase from it. The nanoribbons aligned well along the extrusion direction with the flat faces parallel to the film surface. Their thickness and width are controllable in the range of 65–200 nm and 170 nm–1.23 μm, respectively, by adjusting the ratio of the two Polymers in the blend and processing parameters. Without dissolving the continuous phase, the nanoribbon-containing film shows interesting structural color, chatoyancy, and light polarization effects, and anisotropic mechanical strength. Tape extrusion of phase-separated Polymer blend may offer a simple, scalable way to prepare highly Oriented nanoribbons and functional films.
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Tape Extrusion of Heterogeneous Polymer Blends: Polymer Films with Highly Oriented Nanoribbons, Structural–Optical Property, and Anisotropic Mechanical Strength
Macromolecular Materials and Engineering, 2013Co-Authors: Long Wang, Hongxia Wang, Lian-fang FengAbstract:Highly Oriented Polymer nanoribbons are prepared by tape extrusion of a phase-separated Polymer blend into thin film and by subsequently dissolving the continuous Polymer phase from it. The nanoribbons aligned well along the extrusion direction with the flat faces parallel to the film surface. Their thickness and width are controllable in the range of 65–200 nm and 170 nm–1.23 μm, respectively, by adjusting the ratio of the two Polymers in the blend and processing parameters. Without dissolving the continuous phase, the nanoribbon-containing film shows interesting structural color, chatoyancy, and light polarization effects, and anisotropic mechanical strength. Tape extrusion of phase-separated Polymer blend may offer a simple, scalable way to prepare highly Oriented nanoribbons and functional films.
Sarah H Tolbert - One of the best experts on this subject based on the ideXlab platform.
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control of energy transfer in Oriented conjugated Polymer mesoporous silica composites
Science, 2000Co-Authors: Thucquyen Nguyen, Benjamin J Schwartz, Vinh Doan, Sarah H TolbertAbstract:Nanoscale architecture was used to control energy transfer in semiconducting Polymers embedded in the channels of Oriented, hexagonal nanoporous silica. Polarized femtosecond spectroscopies show that excitations migrate unidirectionally from aggregated, randomly Oriented Polymer segments outside the pores to isolated, aligned Polymer chains within the pores. Energy migration along the conjugated Polymer backbone occurred more slowly than Forster energy transfer between Polymer chains. The different intrachain and interchain energy transfer time scales explain the behavior of conjugated Polymers in a range of solution environments. The results provide insights for optimizing nanostructured materials for use in optoelectronic devices.
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host guest chemistry using an Oriented mesoporous host alignment and isolation of a semiconducting Polymer in the nanopores of an ordered silica matrix
Journal of Physical Chemistry B, 1999Co-Authors: And Adam F Gross, Sarah H TolbertAbstract:Oriented Polymer/silica composites have been synthesized by incorporating the conjugated semiconducting Polymer MEH-PPV into the pores of an aligned, hexagonally ordered mesoporous silica. The ordered silica framework is synthesized by a silica/surfactant coorganization process that proceeds via a silicate/surfactant liquid crystalline intermediate. Magnetic fields are used to orient this liquid crystalline intermediate, followed by chemical cross-linking of the silica framework and removal of the surfactant. Hexagonally ordered (p6mm) aligned silica samples are treated with organic chlorosilanes to optimize interactions between the Polymer and the silica surface. Polymers are incorporated from solution; thermal cycling is used to drive the Polymers into the pores. The resultant Polymer incorporation is monitored by polarized photoluminescence spectroscopy. Polymer chains which are Oriented in the aligned nanoporous silica show strong polarization anisotropy in their photoluminescence (IVV/IVH = 4.4, IHH/...
Long Wang - One of the best experts on this subject based on the ideXlab platform.
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tape extrusion of heterogeneous Polymer blends Polymer films with highly Oriented nanoribbons structural optical property and anisotropic mechanical strength
Macromolecular Materials and Engineering, 2014Co-Authors: Long Wang, Hongxia Wang, Lian-fang FengAbstract:Highly Oriented Polymer nanoribbons are prepared by tape extrusion of a phase-separated Polymer blend into thin film and by subsequently dissolving the continuous Polymer phase from it. The nanoribbons aligned well along the extrusion direction with the flat faces parallel to the film surface. Their thickness and width are controllable in the range of 65–200 nm and 170 nm–1.23 μm, respectively, by adjusting the ratio of the two Polymers in the blend and processing parameters. Without dissolving the continuous phase, the nanoribbon-containing film shows interesting structural color, chatoyancy, and light polarization effects, and anisotropic mechanical strength. Tape extrusion of phase-separated Polymer blend may offer a simple, scalable way to prepare highly Oriented nanoribbons and functional films.
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Tape Extrusion of Heterogeneous Polymer Blends: Polymer Films with Highly Oriented Nanoribbons, Structural–Optical Property, and Anisotropic Mechanical Strength
Macromolecular Materials and Engineering, 2013Co-Authors: Long Wang, Hongxia Wang, Lian-fang FengAbstract:Highly Oriented Polymer nanoribbons are prepared by tape extrusion of a phase-separated Polymer blend into thin film and by subsequently dissolving the continuous Polymer phase from it. The nanoribbons aligned well along the extrusion direction with the flat faces parallel to the film surface. Their thickness and width are controllable in the range of 65–200 nm and 170 nm–1.23 μm, respectively, by adjusting the ratio of the two Polymers in the blend and processing parameters. Without dissolving the continuous phase, the nanoribbon-containing film shows interesting structural color, chatoyancy, and light polarization effects, and anisotropic mechanical strength. Tape extrusion of phase-separated Polymer blend may offer a simple, scalable way to prepare highly Oriented nanoribbons and functional films.
Franz Stelzer - One of the best experts on this subject based on the ideXlab platform.
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Disordered and Oriented polyacetylene-block-polynorbornene-block-polyacetylene
Synthetic Metals, 1991Co-Authors: Franz Stelzer, K. Pressl, Günther Leising, O Leitner, Robert H GrubbsAbstract:Abstract Disordered and Oriented films of polyactylene- block -polynorbornene- block -polyacetylene ( PA-PN-PA ) with different block sizes are investigated by means of electron microscopy, X-ray analysis and polarized infrared spectroscopy. TEM micrographs of WF 6 doped stretched films show a lamellar fine structure resulting from Oriented domains of polyacetylene. Polynorbornene domains are observed, too. X-ray analyses show fibre patterns typical for crystalline domains in the Oriented Polymer, while disordered films only show diffraction rings characteristically for polynorbornene and polyacetylene.
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Polarized Raman spectra of Oriented Polymer systems: polyacetylene and coPolymer polyacetylene-polynorbornene
Synthetic Metals, 1991Co-Authors: E. Mulazzi, Franz Stelzer, Günther Leising, T. Verdon, Serge LefrantAbstract:Abstract In this paper, we present experimental and theoretical Resonance Raman studies carried out on Oriented Polymer systems. It is shown that different Oriented trans polyacetylene samples exhibit Raman features which depend upon the stretching ratio. Also, the depolarization ratio of the Ra,an bands have been found to depend upon the isomerization temperature. Oriented coPolymers polyacetylene/polynorbornene, (CH) x - (NBE) n - (CH) x , have also been studied. Raman spectra of the trans-(CH) x parts of these compounds have been analyzed in the frame of the bimodal distribution model. It is shown that whatever x and n values, results are rather similar in terms of conjugation length. In addition, from IR studies, one can deduce that in the stretched Oriented coPolymers, polynorbornene and polyacetylene segments have a different orientation degree.
Dirk J. Broer - One of the best experts on this subject based on the ideXlab platform.
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ANISOTROPIC THERMAL EXPANSION OF DENSELY CROSS-LINKED Oriented Polymer NETWORKS
Polymer Engineering and Science, 1991Co-Authors: Dirk J. Broer, Grietje N. MolAbstract:Densely cross-linked Oriented Polymer networks are made by in-situ photoPolymerization of Oriented liquid-crystalline diacrylates. Freestanding films that exhibited highly, anisotropic thermal expansion were prepared. The influence of the molecular structure and type and degree of orientation on the anisotrpic thermal expansion is described. The expansion coefficient of uniaxially Oriented networks in the direction of the molecular orientation is slightly positive at temperatures below the glass transition of the networks and becomes negative as soon as this transition sets in the result is an effectively zero expansion over a wide temperature range. By introducing a molecular helix in, the network perpendicular to the film surface, a low thermal expansion is established in two directions in the plane of the film or coating.
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insitu photoPolymerization of Oriented liquid crystalline acrylates 5 influence of the alkylene spacer on the properties of the mesogenic monomers and the formation and properties of Oriented Polymer networks
Macromolecular Chemistry and Physics, 1991Co-Authors: Dirk J. Broer, Grietje N. Mol, Ger ChallaAbstract:The photoinitiated bulk Polymerization of macroscopically Oriented 1,4-phenylene bis{4-(omega-acryloyloxyalkyloxy)benzoate} produces densely crosslinked Oriented Polymer networks. The influence of the length of the alkylene spacer between the aromatic central core and the Polymerizable acrylate end-groups on the mesomorphic behaviour of the monomer, the molecular orientation in the monomeric and Polymeric state and the process of photoinitiated Polymerization in the ordered state is studied. Some optical properties of the Oriented networks are presented.