Thu, 07 Aug 2008 21:28:15 BST CiteULike: Tag polymer http://www.citeulike.org/tag/polymer CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/zamberdine/article/1689391 <i>Nanoscience and Nanotechnology, 2006. ICONN '06. International Conference on (2006)</i><br /><br />A method is reported for the self-assembly of hybrid polymer-gold nanoparticles. To this end a methacrylate block copolymer has been synthesized by radical addition fragmentation chain transfer (RAFT) polymerization. The resultant block copolymer has a sulfur-containing dithiocarbamate end group. Due to the high degree of interaction of sulfur containing functionalities and gold, the dithiocarbamate end groups have been used as a means to generate hybrid polymer gold nanoparticles. The synthesized polymers and nanoparticles have been characterized by a series of analytical techniques, including diffusion ordered NMR spectroscopy (DOSY), which has been utilized to demonstrate block copolymer formation and formation of the polymer-gold hybrids. Synthesis and Characterisation of Hybrid Polymer-Gold Nanoparticles: Towards Novel Biosensors Z Merican TL Schiller PM Fredericks I Blakey Nanoscience and Nanotechnology, 2006. ICONN '06. International Conference on (2006) 2007-09-24T12:31:57-00:00 2006 Nanoscience and Nanotechnology, 2006. ICONN '06. International Conference on gold nanoparticles polymer raft http://www.citeulike.org/user/weeks/article/1981483 <i>(15 August 2002)</i><br /><br />The physics of soft condensed matter is probably one of the most 'fashionable' areas in the physical sciences today. This book offers a coherent and clear introduction to the properties and behaviour of soft matter. It begins with a treatment of the general underlying principles: the relation of the structure and dynamics of solids and liquids to intermolecular forces, the thermodynamics and kinetics of phase transitions, and the principles of self-assembly. Then the specific properties of colloids, polymers, liquid crystals and self-assembling amphiphilic systems are treated within this framework. A concluding chapter illustrates how principles of soft matter physics can be used to understand properties of biological systems. The focus on the essentials and the straightforward approach make the book suitable for students with either a theoretical or an experimental bias. The level is appropriate for final year undergraduates and beginning graduate students in physics, chemistry, materials science, and chemical engineering. Soft Condensed Matter Richard Jones (15 August 2002) 2007-11-25T16:48:27-00:00 2002 Oxford University Press, USA book complex-fluids polymer surfactants http://www.citeulike.org/user/weeks/article/1998280 <i>European Polymer Journal, Vol. 40, No. 5. (May 2004), pp. 1019-1026.</i><br /><br />The orientational and translational motion of individual dye molecules embedded in a polymer matrix is studied in the temperature regime above the glass transition. The rotational diffusion close to the glass transition is heterogeneous on the single molecule level and few sudden changes in the reorientational speed of single molecules are found. The exchange between these reorientational speeds is found to be one order of magnitude slower than the reorientational time constant of the molecules. Translational motion can be clearly identified at about 1.2 Tg. However, the translational diffusion shows no signs of heterogeneity on the timescale of our experiments, from which we conclude, that the timescale of the exchange process between microenvironments has become too fast or that no heterogeneity exists at the temperatures above 1.2 Tg. Reorientation and translation of individual dye molecules in a polymer matrix A Schob F Cichos J Schuster C von Borczyskowski doi:10.1016/j.eurpolymj.2004.01.016 European Polymer Journal, Vol. 40, No. 5. (May 2004), pp. 1019-1026. 2007-11-28T00:34:21-00:00 2004 European Polymer Journal 40 5 1019 1026 dyn-het polymer rotation http://www.citeulike.org/user/weeks/article/2945613 <i>Science, Vol. 267, No. 5206. (31 March 1995), pp. 1945-1947.</i><br /><br />Physical aging refers to structural relaxation of the glassy state toward the metastable equilibrium amorphous state, and it is accompanied by changes in almost all physical properties. These changes, which must be taken into account in the design, manufacture, and use of glassy polymer materials and devices, present a daunting challenge to theorists. 10.1126/science.267.5206.1945 Physical Aging in Polymer Glasses Ian Hodge doi:10.1126/science.267.5206.1945 Science, Vol. 267, No. 5206. (31 March 1995), pp. 1945-1947. 2008-06-30T18:26:16-00:00 1995 Science 267 5206 1945 1947 aging polymer review http://www.citeulike.org/user/weeks/article/2067349 <i>Physical Review Letters, Vol. 79, No. 1. (7 July 1997), 103.</i><br /><br />Comparisons are made of the translational and rotational diffusion of small-molecule probes in a polymer near its glass transition temperature; T g . In the rubbery state; 1.1 T g > T > T g ; translational diffusion is much less temperature dependent than rotational reorientation; in a “quenched” glass; translation and rotation have similar temperature dependencies. This is explained to be a consequence of the fact that in the rubbery state near T g the breadth of the polymer relaxation distribution is strongly temperature dependent; while in the quenched glass it is temperature invariant. Translation-Rotation Paradox for Diffusion in Glass-Forming Polymers: The Role of the Temperature Dependence of the Relaxation Time Distribution David Hall Ali Dhinojwala John Torkelson doi:10.1103/PhysRevLett.79.103 Physical Review Letters, Vol. 79, No. 1. (7 July 1997), 103. 2007-12-06T15:38:54-00:00 1997 Physical Review Letters 79 1 103 American Physical Society journal-club polymer rotation http://www.citeulike.org/user/weeks/article/1836362 <i>Nat Mater, Vol. 2, No. 10. (October 2003), pp. 695-700.</i><br /><br />Despite the decade-long study of the effect of nanoconfinement on the glass-transition temperature (Tg) of amorphous materials, the quest to probe the distribution of Tgs in nanoconfined glass formers has remained unfulfilled. Here the distribution of Tgs across polystyrene films has been obtained by a fluorescence/multilayer method, revealing that the enhancement of dynamics at a surface affects Tg several tens of nanometres into the film. The extent to which dynamics smoothly transition from enhanced to bulk states depends strongly on nanoconfinement. When polymer films are sufficiently thin that a reduction in thickness leads to a reduction in overall Tg, the surface-layer Tg actually increases with a reduction in overall thickness, whereas the substrate-layer Tg decreases. These results indicate that the gradient in Tg dynamics is not abrupt, and that the size of a cooperatively rearranging region is much smaller than the distance over which interfacial effects propagate. The distribution of glass-transition temperatures in nanoscopically confined glass formers Christopher Ellison John Torkelson doi:10.1038/nmat980 Nat Mater, Vol. 2, No. 10. (October 2003), pp. 695-700. 2007-10-29T17:55:32-00:00 2003 Nat Mater 2 10 695 700 confinement glass journal-club polymer http://www.citeulike.org/user/weeks/article/1836349 <i>Science, Vol. 309, No. 5733. (15 July 2005), pp. 456-459.</i><br /><br />We analyzed the glassy-state structural relaxation of polymers near surfaces and interfaces by monitoring fluorescence in multilayer films. Relative to that of bulk, the rate of structural relaxation of poly(methyl methacrylate) is reduced by a factor of 2 at a free surface and by a factor of 15 at a silica substrate interface; the latter exhibits a nearly complete arresting of relaxation. The distribution in relaxation rates extends more than 100 nanometers into the film interior, a distance greater than that over which surfaces and interfaces affect the glass transition temperature. 10.1126/science.1112217 Structural Relaxation of Polymer Glasses at Surfaces, Interfaces, and In Between Rodney Priestley Christopher Ellison Linda Broadbelt John Torkelson doi:10.1126/science.1112217 Science, Vol. 309, No. 5733. (15 July 2005), pp. 456-459. 2007-10-29T17:51:36-00:00 2005 Science 309 5733 456 459 confinement glass polymer http://www.citeulike.org/user/weeks/article/3089279 <i>Journal of Physics: Condensed Matter, Vol. 15, No. 11. (2003), pp. S737-S763.</i><br /><br />There has been considerable interest in the impact of mechanical stresses on the thermodynamic state of glassy materials over the past quarter century--beginning with Struik's hypothesized erasure of ageing by large stresses. In particular, there has been a recent application of the ideas of erasure or rejuvenation in the general literature on glasses and glass-like substances. For this reason we here examine the evidence for and against rejuvenation and show several sets of data that argue strongly against rejuvenation or erasure of ageing as viable explanations for the interactions between large mechanical stimuli and the structure of the glass. Two particular experimental conditions are of significance here. First, measurements that are made in the sub-yield region and close to the glass transition allow the direct measurement of the evolution of the glassy response both with and without applying any stress. For example, in torsional dilatometry experiments where the volume recovery is measured simultaneously and in the same apparatus as the mechanical response, it is found that the baseline volume recovery is unaffected by the applied stress. The second class of experiments has been post-yield experiments, where the rejuvenation hypothesis is more difficult to reject. However, observations that post-yield ageing leads to evolution into a different 'equilibrium' state as measured by the recovered yield stress suggest that yielding does not rejuvenate the glass, but it may lead to a sort of polyamorphism or new deformation induced phase. We also present results of mechanically induced 'implosion' in polymers far below the glass temperature that suggest that mechanical stimuli may actually accelerate ageing rather than rejuvenating the glass. Finally, the origins of the power-law dependence on ageing time (also termed elapsed or waiting time) of the mechanical relaxation time are discussed, and the use of the elapsed time as a natural variable to describe ageing is shown not to be appropriate for structural glasses. Mechanical rejuvenation in polymer glasses: fact or fallacy? Gregory Mckenna doi:10.1088/0953-8984/15/11/301 Journal of Physics: Condensed Matter, Vol. 15, No. 11. (2003), pp. S737-S763. 2008-08-05T18:18:48-00:00 2003 Journal of Physics: Condensed Matter 15 11 S737 S763 aging polymer http://www.citeulike.org/user/weeks/article/941006 <i>Physical Review Letters, Vol. 81, No. 18. (2 November 1998), 4004.</i><br /><br />We explore the entropic interactions between a pair of micron-sized colloidal spheres in DNA solutions. By confining the particles in a line-scanned optical tweezer; we directly measured the functional form of the interaction potential with sub- k B T resolution in samples where the spheres and the polymer coils were of comparable size. The potential is well described by the Asakura-Oosawa depletion model even in the semidilute regime where DNA coils overlap strongly. Its range and depth increase with increasing concentration in a manner consistent with a crossover from a dilute solution of Gaussian coils to the weakly fluctuating semidilute regime dominated by two-point collisions which is unique to semiflexible polymers. Entropic Colloidal Interactions in Concentrated DNA Solutions Ritu Verma JC Crocker TC Lubensky AG Yodh doi:10.1103/PhysRevLett.81.4004 Physical Review Letters, Vol. 81, No. 18. (2 November 1998), 4004. 2006-11-13T02:10:42-00:00 1998 Physical Review Letters 81 18 4004 American Physical Society depletion laser-tweezer polymer http://www.citeulike.org/user/weeks/article/1790109 <i>The Journal of Chemical Physics, Vol. 126, No. 13. (2007)</i><br /><br />Grand canonical Monte Carlo simulation and simple statistical thermodynamic theory are used to model the aggregation and phase separation of systems of reversibly polymerizing monomers, capable of forming chains with or without the ability to cyclize into rings, with isotropic square-well attractions between nonbonded pairs of monomers. The general trend observed in simulation of chain-only systems, as predicted in a number of published theoretical works, is that the critical temperature for phase separation increases and the critical monomer density decreases with rising polymer bond strength. Introduction of the equilibrium between chains and rings into the theory lowers the predicted critical temperature and increases the predicted critical density. While the chain-only theories predict a vanishing critical density in the limit of complete polymerization, when ring formation is taken into account the predicted critical density in the same limit approaches the density of the onset of the ring-chain transition. The theoretically predicted effect of cyclization on chemical potential is in good qualitative agreement with a subset of simulation results in which chain-only systems were compared with equilibrium mixtures of rings and chains. The influence of attractions on the aggregation number and radius of gyration of chains and rings observed in simulations is also discussed. ©2007 American Institute of Physics Simulation and theory of flexible equilibrium polymers under poor solvent conditions Lakedra Pam Larissa Spell James Kindt doi:10.1063/1.2714945 The Journal of Chemical Physics, Vol. 126, No. 13. (2007) 2007-10-19T18:45:03-00:00 2007 The Journal of Chemical Physics 126 13 AIP polymer http://www.citeulike.org/user/weeks/article/1835912 <i>Macromolecules, Vol. 40, No. 7. (3 April 2007), pp. 2568-2574.</i><br /><br />Abstract: By selective placement of fluorescent dyes, we have measured the glass transition temperature (Tg) of individual layers within supported bilayer films of different polymers to determine the extent to which strong free-surface effects and substrate interactions are mediated by a narrow interface between immiscible polymers. We have discovered that the impact a free surface has on Tg within an ultrathin PS layer is extremely sensitive to the polymer species used in the underlayer. The large Tg reduction of ~32 K relative to bulk Tg observed for a 14 nm thick surface layer of polystyrene (PS) supported on bulk PS is virtually eliminated when a 14 nm thick surface layer of PS is placed on an underlayer of poly(methyl methacrylate) or poly(2-vinylpyridine) (P2VP), even of bulk thickness. Thus, the cooperative segmental mobility associated with the Tg of the PS free-surface layer is greatly hindered by the narrow, several-nanometer-wide interfacial region formed with the dissimilar polymer underlayer. This indicates that the dynamics of nanoscale layers can be strongly modified by adjacent layers or domains of unlike polymers via propagation of effects across an interfacial layer of cooperatively rearranging regions containing segments of the two immiscible polymers, which has important implications for multilayer films and nanostructured blends. Conversely, the Tg of an ultrathin P2VP film is unaffected by the presence of a PS capping layer, indicating that strong attractive interactions of P2VP with hydroxyl groups on the surface of the silica substrate dominate over a much weaker free-surface effect in P2VP. Eliminating the Enhanced Mobility at the Free Surface of Polystyrene: Fluorescence Studies of the Glass Transition Temperature in Thin Bilayer Films of Immiscible Polymers CB Roth KL Mcnerny WF Jager JM Torkelson doi:10.1021/ma062864w Macromolecules, Vol. 40, No. 7. (3 April 2007), pp. 2568-2574. 2007-10-29T15:23:15-00:00 2007 Macromolecules 40 7 2568 2574 confinement polymer http://www.citeulike.org/user/wangsd/article/612952 <i>Nature, Vol. 441, No. 7089., pp. 65-68.</i> Metallic transport in polyaniline Kwanghee Lee Shinuk Cho Sung Park AJ Heeger Chan-Woo Lee Suck-Hyun Lee doi:10.1038/nature04705 Nature, Vol. 441, No. 7089., pp. 65-68. 2006-05-04T03:18:26-00:00 Nature 0028-0836 441 7089 65 68 Nature Publishing Group incommensurate localization polymer http://www.citeulike.org/user/wangsd/article/681009 <i>(31 May 2006)</i><br /><br />The family of molecular conductors TMTTF/TMTSF-X demonstrates almost all known electronic phases in parallel with a set of weak structural modifications of anion ordering and mysterious structureless transitions. Only in early 2000's their nature became elucidated by discoveries of a huge anomaly in the dielectric permittivity and by the NMR evidences for the charge ordering (disproportionation). The observations have been interpreted as the never expected ferroelectric transition. The phenomenon unifies a variety of different concepts and observations in quite unusual aspects or conjunctions: ferroelectricity of good conductors, structural instability towards the Mott-Hubbard state, Wigner crystallization in a dense electronic system, the ordered 4K_F density wave, richness of physics of solitons, the interplay of structural and electronic symmetries. The corresponding theory of the "combined Mott-Hubbard state" deals with orthogonal contributions to the Umklapp scattering of electrons coming from the two symmetry breaking effects: the build-in nonequivalence of bonds and the spontaneous nonequivalence of sites. The state gives rise to several types of solitons, all of them showing in experiments. On this basis we can interpret the complex of existing and future experiments as optical absorption and photoconductivity, combined ferroelectric resonance and the phonon anti-resonance, plasma frequency reduction. Ferroelectricity and Charge Ordering in Quasi One-Dimensional Organic Conductors Serguei Brazovskii (31 May 2006) 2006-06-02T07:11:35-00:00 2006 polymer http://www.citeulike.org/user/waitonhill/article/1259592 <i>Science, Vol. 300, No. 5619. (25 April 2003), pp. 619-622.</i><br /><br />We present experimental evidence, obtained from small-angle neutron scattering and photon correlation measurements, indicating the existence of two types of structurally arrested (glassy) states in a copolymer micellar system with a short-range interparticle attractive interaction. Within a certain range of micellar volume fractions, a sharp transition between these two types of glass is observed by varying the temperature. Furthermore, we found an end point of this transition line beyond which the two glasses become identical in their local structure and their long-time dynamics. These findings confirm the recent mode-coupling theory predictions regarding the phase behavior of the structurally arrested states for this type of system. 10.1126/science.1082364 The Glass-to-Glass Transition and Its End Point in a Copolymer Micellar System Sow-Hsin Chen Wei-Ren Chen Francesco Mallamace doi:10.1126/science.1082364 Science, Vol. 300, No. 5619. (25 April 2003), pp. 619-622. 2007-04-27T09:43:05-00:00 2003 Science 300 5619 619 622 glass polymer http://www.citeulike.org/user/uyogesh/article/2482078 <i>Anal. Lett., Vol. 41, No. 2. (2008), pp. 210-243.</i><br /><br />Carbon Nanotubes (CNTs) with polymers are promising new sensing materials for biosensors, which have the characteristics of low weight of extraordinary mechanical, electrical, thermal, and multifunctional properties. The size scale, aspect ratio, and properties of CNTs provide advantages in a variety of sensor applications. The various processing methods for these nanocomposites are discussed in particular, CNT synthesis, purification of CNTs, pretreatment and functionalization of CNTs, different dispersion methods, and electropolymerization of the monomers. The advantages of these composite modified electrodes toward biosensors have also been presented in detail. Some key results from each article are summarized by relating the concept and mechanism behind each sensor, experimental conditions, and the behavior of the sensors at different conditions, etc. Copyright © Taylor & Francis Group, LLC. Recent trends in the application of carbon nanotubes-polymer composite modified electrodes for biosensors: A review U Yogeswaran SM Chen doi:10.1080/00032710701792638 Anal. Lett., Vol. 41, No. 2. (2008), pp. 210-243. 2008-03-07T06:23:48-00:00 2008 Anal. Lett. 41 2 210 243 carbon cnts composite double dwcnts multi mwcnts nano nanotubes polymer single swcnts walled http://www.citeulike.org/user/tempestblue/article/392477 <i>Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol. 221, No. 1-3. (15 July 2003), pp. 49-53.</i><br /><br />Liposomes of the acidic phospholipid, -[alpha]-dimyristoylphosphatidic acid (DMPA), were prepared via suitable pH modification of its aqueous solution at 40 [deg]C. Transition electron microscopy (TEM) verified the presence of hollow lipid vesicles. Through adsorption of the polyelectrolyte poly(allylamine hydrochloride) (PAH) onto negatively charged DMPA liposomes we found that such surface-modified liposomes cannot be destroyed by the detergent, sodium dodecyl sulfonate (SDS). Thus polymer-stabilized liposomes are obtained. Phospholipid liposomes stabilized by the coverage of polyelectrolyte Liqin Ge Helmuth Mohwald Junbai Li doi:10.1016/S0927-7757(03)00106-7 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol. 221, No. 1-3. (15 July 2003), pp. 49-53. 2005-11-14T17:50:59-00:00 2003 Colloids and Surfaces A: Physicochemical and Engineering Aspects 221 1-3 49 53 encapsulation liposomes polymer http://www.citeulike.org/user/Tarrow/article/786442 <i>The Journal of Chemical Physics, Vol. 109, No. 22. (1998), pp. 10018-10027.</i><br /><br />A self-consistent reptation theory that accounts for chain-tube interactions, segment connectivity, chain-length breathing, segmental stretch, and constraint release is proposed. Simulation results are compared semiquantitatively to experimental observations in single-step strain flows. Since stochastic simulation techniques are used, no approximations, such as independent alignment or consistent averaging are needed to obtain results. The simulation results show excellent agreement with experimental trends in shear and normal stress relaxations, including the second normal stress difference, well into the nonlinear regime. For most of these experiments, the original Doi and Edwards theory, which incorporates independent alignment or consistent averaging, is not satisfactory. In the following companion paper, we show how the model is capable of describing double-step-strain flows for all stress components. Subsequent papers show excellent agreement for the inception of steady shear flow, and steady shear flow. ©1998 American Institute of Physics. Segment connectivity, chain-length breathing, segmental stretch, and constraint release in reptation models. I. Theory and single-step strain predictions Chi Hua Jay Schieber doi:10.1063/1.477670 The Journal of Chemical Physics, Vol. 109, No. 22. (1998), pp. 10018-10027. 2006-08-04T17:41:48-00:00 1998 The Journal of Chemical Physics 109 22 10018 10027 AIP polymer relaxation reptation theory http://www.citeulike.org/user/taqayara/article/1294617 <i>Biomaterials, Vol. 24, No. 24. (November 2003), pp. 4385-4415.</i><br /><br />Since RGD peptides (R: arginine; G: glycine; D: aspartic acid) have been found to promote cell adhesion in 1984 (Cell attachment activity of fibronectin can be duplicated by small synthetic fragments of the molecule, Nature 309 (1984) 30), numerous materials have been RGD functionalized for academic studies or medical applications. This review gives an overview of RGD modified polymers, that have been used for cell adhesion, and provides information about technical aspects of RGD immobilization on polymers. The impacts of RGD peptide surface density, spatial arrangement as well as integrin affinity and selectivity on cell responses like adhesion and migration are discussed. RGD modified polymers: biomaterials for stimulated cell adhesion and beyond Ulrich Hersel Claudia Dahmen Horst Kessler Biomaterials, Vol. 24, No. 24. (November 2003), pp. 4385-4415. 2007-05-14T09:05:43-00:00 2003 Biomaterials 24 24 4385 4415 modified polymer http://www.citeulike.org/user/taqayara/article/1299863 <i>Biomaterials, Vol. 19, No. 11-12. (June 1998), pp. 979-986.</i><br /><br />Cell functions are regulated by signal transduction processes triggered by binding interactions with extracellular ligands, including those coupled to insoluble matrices as well as those diffusing in free solution. Whereas receptor interactions with freely diffusible soluble ligands are quantitatively governed by the mean ligand concentration, interactions with spatially constrained substratum-bound ligands may be affected not only by the mean ligand concentration, but also by the ligand spatial microdistribution. To probe this hypothesis we have generated surfaces presenting galactose ligands at different concentrations and different capabilities for micromobility - and thus spatial microdistribution - by means of polyethylene oxide tethering and assayed for hepatocyte spreading mediated by asialoglycoprotein receptor/cytoskeleton linkages. We demonstrate that spreading is not uniquely determined by the mean galactose concentration presented by the culture substrate. Rather, the ability of primary hepatocytes to spread is additionally specified by a combination of ligand concentration and tether length. Our results suggest spreading results when monovalent ligands possess sufficient mobility to form effectively multivalent bonds with the receptor; that is, when the substratum-bound ligands to cluster in spatial microdomains. Microdistribution of substratum-bound ligands affects cell function: hepatocyte spreading on PEO-tethered galactose Linda Griffith Stephanie Lopina Biomaterials, Vol. 19, No. 11-12. (June 1998), pp. 979-986. 2007-05-16T11:13:59-00:00 1998 Biomaterials 19 11-12 979 986 polymer http://www.citeulike.org/user/SynTact/article/493696 <i>Sensors and Actuators B: Chemical, Vol. 79, No. 2-3. (15 October 2001), pp. 107-114.</i><br /><br />Electroosmotic flow (EOF) micropumps which use electroosmosis to transport liquids have been fabricated and used to achieve pressures in excess of 20 atm and flow rates of 3.6 [mu]l/min for 2 kV applied potentials. These pumps use deionized water as working fluids in order to reduce the ion current of the pump during operation and increase thermodynamic efficiency. EOF pumps are fabricated by packing the 3.5 [mu]m diameter non-porous silica particles into 500-700 [mu]m diameter fused-silica capillaries and by using a silicate frit fabrication process to hold the particles in place. The devices have no moving parts and can operate as both open (high flow rate) and closed (high pressure) systems. Pressure versus flow rate performance data are presented and combined with measurements of physical dimensions, dry and wet weight, and ion current to calculate the pump structure porosity, tortuosity, effective pore radius, and zeta potential. Fabrication and characterization of electroosmotic micropumps Shulin Zeng Chuan-Hua Chen Jr Mikkelsen Juan Santiago doi:10.1016/S0925-4005(01)00855-3 Sensors and Actuators B: Chemical, Vol. 79, No. 2-3. (15 October 2001), pp. 107-114. 2006-02-04T01:26:48-00:00 2001 Sensors and Actuators B: Chemical 79 2-3 107 114 fabrication polymer http://www.citeulike.org/user/SynTact/article/507367 <i>Biosensors and Bioelectronics, Vol. 19, No. 10. (15 May 2004), pp. 1309-1318.</i><br /><br />The study of intracellular communication requires devices that can not only monitor the bioelectric activity, but also control and observe the biochemical environment at the cellular level. This paper reports on the development and characterisation of implantable polyimide microprobes that allow simultaneous, selective chemical delivery/probing and multi-channel recording/stimulation of bioelectric activity. The key component of the system is a flexible polyimide substrate with embedded microchannels that is batch-fabricated combining polyimide micromachining and a lamination technique. The devices provide platinum microelectrodes on both sides of the polyimide substrate with an active surface between 20 [mu]m x 20 [mu]m and 50 [mu]m x 50 [mu]m. The embedded microchannels permit highly localised drug delivery or probing at the tip of the device via channel outlets adjacent to the microelectrodes. The microelectrodes were characterised by electrical impedance spectroscopy and the microchannels were studied in microflow experiments. Two different fluid delivery schemes were explored in two different designs. The first device type consists of a simple combination of microchannels and microelectrodes on one substrate. Liquids are ejected at the tip of the device by pressure injection techniques. The second device was inspired by the so-called U-tube concept allowing for highly localised delivery of controlled amounts of liquids in the picoliters range. Thus, the influence of chemical compounds on the electrical activity of cells can be studied with high temporal and spatial resolution. The flexible, implantable devices can be used for studying the chemical and electrical information exchange and communication of cells in in vivo and in vitro experiments. Flexible polyimide probes with microelectrodes and embedded microfluidic channels for simultaneous drug delivery and multi-channel monitoring of bioelectric activity S Metz A Bertsch D Bertrand Ph Renaud doi:10.1016/j.bios.2003.11.021 Biosensors and Bioelectronics, Vol. 19, No. 10. (15 May 2004), pp. 1309-1318. 2006-02-16T23:45:13-00:00 2004 Biosensors and Bioelectronics 19 10 1309 1318 microfluidics polymer http://www.citeulike.org/user/SynTact/article/634892 <i>Synthetic Metals, Vol. 154, No. 1-3. (22 September 2005), pp. 25-28.</i><br /><br />This project is focused on developing novel smart textiles based on conducting polymer coatings deposited on a foam substrate. This process renders the foam conductive, while retaining the tactile properties of the original material. The foam is a soft, porous and conductive solid, made by chemically oxidising pyrrole in the presence of a polyurethane foam. The 3-D structure of this material means it is sensitive to pressures exerted from all three dimensions, making it attractive for use in wearable sensors for sport and medical applications. A potential application under investigation is the development of a smart insole for patients with Diabetes Mellitus, who require constant monitoring of the pressure exerted underfoot during walking or standing in order to reduce the risk of damaging their feet due to excess pressure being applied. Future applications for this material may also lie in the area of wearable electronic components, whereby the material can be fabricated to produce resistors, capacitors, etc. The gas sensing capabilities of this material were also investigated. Results have shown that this smart fabric based chemical sensor offers higher selectivity towards ammonia over other volatile organic vapours. The Development and Characterisation of Conducting Polymeric-based Sensing Devices S Brady KT Lau W Megill GG Wallace D Diamond doi:10.1016/j.synthmet.2005.07.008 Synthetic Metals, Vol. 154, No. 1-3. (22 September 2005), pp. 25-28. 2006-05-15T00:06:40-00:00 2005 Synthetic Metals 154 1-3 25 28 polymer tactile http://www.citeulike.org/user/Sputnik1/article/2238334 <i>Journal of Electrostatics, Vol. 58, No. 1-2. (May 2003), pp. 3-16.</i><br /><br />Tribo-electric charging of polymers can be considered as an interfacial phenomenon of interacting polymer surfaces. The electron pair acceptor/donor properties of the polymer surfaces determine the polymer's charging. This can be shown by an excellent linear correlation between the electron pair acceptor/donor parameters [alpha] and [beta] and the measured amount of surface charges. Furthermore, the rate of charging corresponds also with the surface polarity parameters. Water adsorption influences the charging mechanism. Several polymers show an increased uptake of water which forms adsorption or swollen layers with increasing the atmospheric humidity. In these cases, the fundamental electron pair interaction mechanism is influenced by an additional ion conductivity. Polymer tribo-electric charging: dependence on thermodynamic surface properties and relative humidity Erno Nemeth Victoria Albrecht Gert Schubert Frank Simon doi:10.1016/S0304-3886(02)00137-7 Journal of Electrostatics, Vol. 58, No. 1-2. (May 2003), pp. 3-16. 2008-01-16T09:18:58-00:00 2003 Journal of Electrostatics 58 1-2 3 16 charge charging humidity polymer properties surface tribo-electric http://www.citeulike.org/user/sp80_smile/article/2362078 <i>The Journal of Chemical Physics, Vol. 123, No. 14. (2005)</i><br /><br />  Dynamics of polymers in a particle-based mesoscopic solvent K Mussawisade M Ripoll RG Winkler G Gompper The Journal of Chemical Physics, Vol. 123, No. 14. (2005) 2008-02-11T09:39:03-00:00 2005 The Journal of Chemical Physics 123 14 AIP chain polymer simulation http://www.citeulike.org/user/sp80_smile/article/866506 <i>(24 November 1988)</i><br /><br /> This book provides a comprehensive account of the modern theory for the dynamical properties of polymer solutions. The theory has undergone dramatic evolution over the last two decades due to the introduction of new methods and concepts that have extended the frontier of theory from dilute<br>solutions in which polymers move independently to concentrated solutions where many polymers converge. Among the properties examined are viscoelasticity, diffusion, dynamic light scattering, and electric birefringence. Nonlinear viscoelasticity is discussed in detail on the basis of molecular<br>dynamical models. The book bridges the gap between classical theory and new developments, creating a consistent picture of polymer solution dynamics over the entire concentration range. The Theory of Polymer Dynamics (The International Series of Monographs on Physics) M Doi SF Edwards (24 November 1988) 2006-09-24T05:39:20-00:00 1988 Oxford University Press, USA dynamics polymer http://www.citeulike.org/user/sp80_smile/article/2272650 <i>Computer Physics Communications, Vol. 147, No. 1-2. (1 August 2002), pp. 538-543.</i><br /><br />The interaction of polymers with small-scale velocity gradients can trigger a coil-stretch transition in the polymers. We analyze this transition within a direct numerical simulation of shear turbulence with an Oldroyd-B model for the polymer. In the coiled state the lengths of polymers are distributed algebraically with an exponent 2[gamma]-1/De, where [gamma] is a characteristic stretching rate of the flow and De the Deborah number. In the stretched state we demonstrate that the length distribution of the polymers is limited by the feedback to the flow. Stretching of polymers in a turbulent environment Bruno Eckhardt Jochen Kronjager Jorg Schumacher doi:10.1016/S0010-4655(02)00339-9 Computer Physics Communications, Vol. 147, No. 1-2. (1 August 2002), pp. 538-543. 2008-01-22T09:20:43-00:00 2002 Computer Physics Communications 147 1-2 538 543 polymer profile shear http://www.citeulike.org/user/sp80_smile/article/2361409 <i>The Journal of Chemical Physics, Vol. 111, No. 17. (1999), pp. 8225-8239.</i><br /><br />  Simulation of a single polymer chain in solution by combining lattice Boltzmann and molecular dynamics Patrick Ahlrichs Burkhard Dünweg The Journal of Chemical Physics, Vol. 111, No. 17. (1999), pp. 8225-8239. 2008-02-11T05:24:43-00:00 1999 The Journal of Chemical Physics 111 17 8225 8239 AIP chain polymer simulation http://www.citeulike.org/user/soheir/article/480993 <i>International Journal of Pavement Engineering, Vol. 7, No. 1. (March 2006), pp. 63-71.</i> Strength characteristics of polymer modified mixes Pawan Kumar Satish Chandra Sunil Bose doi:10.1080/10298430500495147 International Journal of Pavement Engineering, Vol. 7, No. 1. (March 2006), pp. 63-71. 2006-01-25T22:09:44-00:00 2006 International Journal of Pavement Engineering 1029-8436 7 1 63 71 Taylor and Francis Ltd modified pavement polymer http://www.citeulike.org/user/softsimu/article/889452 <i>Physical Review Letters, Vol. 66, No. 23. (10 June 1991), 2996.</i><br /><br />The dynamics of a single polymer chain immersed in a large number of solvent particles is studied by molecular dynamics. This is the first simulation where chain length (30; 40; and 60 monomers) and statistical accuracy are sufficient to test the predictions of the Zimm model as a result of the particle-particle interactions: The short-time diffusion constant is in good agreement with the Kirkwood prediction; and the monomer motions exhibit the expected dynamic scaling. The long-range hydrodynamic interaction requires a data analysis that explicitly includes the periodic images via Ewald sums. Microscopic verification of dynamic scaling in dilute polymer solutions: A molecular-dynamics simulation Burkhard Dã¼nweg Kurt Kremer doi:10.1103/PhysRevLett.66.2996 Physical Review Letters, Vol. 66, No. 23. (10 June 1991), 2996. 2006-10-08T12:50:22-00:00 1991 Physical Review Letters 66 23 2996 American Physical Society factor polymer scaling structure http://www.citeulike.org/user/smcc/article/3000246 <i>(21 June 2006)</i><br /><br />In recent years the development of new technologies has permited the production of 'functional' or 'smart' textiles. These fabrics are capable of sensing changes in environmental conditions or body functions and are adequately responding to them. They are able to absorb substances from the skin or to release therapeutic or cosmetic compounds. For instance, they can be used in underwear with an integrated cardio-online system or as textiles with carrier molecules. The focal point of interest in biofunctional textiles lies currently on the use of textiles supporting therapy and prevention in dermatology. Biofunctional Textiles And the Skin (Current Problems in Dermatology) (21 June 2006) 2008-07-14T20:56:10-00:00 2006 S. Karger AG (Switzerland) body clothing polymer science skin http://www.citeulike.org/user/skirnir/article/2301326 <i>Reviews of Modern Physics, Vol. 60 (July 1988), 781.</i><br /><br />Self-localized nonlinear excitations (solitons; polarons; and bipolarons) are fundamental and inherent features of quasi-one-dimensional conducting polymers. Their signatures are evident in many aspects of the physical and chemical properties of this growing class of novel materials. As a result; these polymers represent an opportunity for exploring the novel phenomena associated with topological solitons and their linear confinement which results from weakly lifting the ground-state degeneracy. The authors review the theoretical models that have been developed to describe the physics of polyacetylene and related conducting polymers and summarize the relevant experimental results obtained for these materials. An attempt is made to assess the validity of the soliton model of polyacetylene and its generalization to related systems in which the ground-state degeneracy has been lifted. Solitons in conducting polymers AJ Heeger S Kivelson JR Schrieffer Su doi:10.1103/RevModPhys.60.781 Reviews of Modern Physics, Vol. 60 (July 1988), 781. 2008-01-29T09:08:54-00:00 1988 Reviews of Modern Physics 60 781 American Physical Society doping polymer http://www.citeulike.org/user/skirnir/article/2371002 <i>Reviews of Modern Physics, Vol. 78, No. 3. (2006)</i><br /><br />Small-molecule organic semiconductors, together with polymers, form the basis for the emerging field of organic electronics. Despite the rapid technological progress in this area, our understanding of fundamental electronic properties of these materials remains limited. Recently developed organic field-effect transistors (OFETs) based on single crystals of small-molecule organic materials are characterized by an unprecedented quality and reproducibility. These devices provide a unique tool to study the fundamentals of polaronic transport on organic surfaces and to explore the limits of OFET performance. This Colloquium focuses on the intrinsic, not limited by static disorder, charge transport in single-crystal OFETs and on the nature of defects on surfaces of organic crystals. In the conclusion, an outline of the outstanding problems that are now becoming within experimental reach owing to the development of single-crystal OFETs is presented. Colloquium: Electronic transport in single-crystal organic transistors ME Gershenson V Podzorov AF Morpurgo doi:10.1103/RevModPhys.78.973 Reviews of Modern Physics, Vol. 78, No. 3. (2006) 2008-02-13T17:09:20-00:00 2006 Reviews of Modern Physics 78 3 APS electronics polymer review http://www.citeulike.org/user/skirnir/article/2369327 <i>Reviews of Modern Physics, Vol. 73, No. 3. (2001), 713.</i><br /><br />The Nobel Prize in Chemistry 2000 was awarded for our discovery and development of conducting polymers; but that discovery only happened after much work on polyacetylene. In this lecture; I would like to talk about the early investigations that preceded and eventually led to the discovery of chemical doping. I do hope my talk will be of use for you; the audience; to deepen your understanding of what had happened before and how we arrived at the idea of chemical doping. Nobel Lecture: The discovery of polyacetylene film—the dawning of an era of conducting polymers Hideki Shirakawa doi:10.1103/RevModPhys.73.713 Reviews of Modern Physics, Vol. 73, No. 3. (2001), 713. 2008-02-13T11:02:05-00:00 2001 Reviews of Modern Physics 73 3 713 American Physical Society electronics polymer http://www.citeulike.org/user/skirnir/article/2369159 <i>Applied Physics Letters, Vol. 86, No. 14. (2005)</i><br /><br />  Hybrid light-emitting polymer device fabricated on a metallic nanowire array AE Strevens A Drury SM Lipson M Kröll WJ Blau HH Hörhold Applied Physics Letters, Vol. 86, No. 14. (2005) 2008-02-13T10:06:28-00:00 2005 Applied Physics Letters 86 14 AIP led polymer http://www.citeulike.org/user/skirnir/article/2239461 <i>Physics of the Solid State, Vol. 49, No. 11. (20 November 2007), pp. 2015-2033.</i><br /><br />Abstract  Recent advances in the synthesis of nanowires based on conducting conjugated polymers are described. The results of recent experimental studies of the electrical properties of polymer nanowires are critically analyzed. The applicability of various theoretical models of tunneling in one-dimensional conductors (variable-range hopping conductivity, Luttinger liquid, Wigner crystal, etc.) to the interpretation of the experimental data on the electronic transport in polymer nanosystems is discussed. A phenomenological model is proposed describing the mechanism of transport in polymer nanowires with allowance for the quasi-one-dimensional nature of molecules of conjugated polymers. The first applications of polymer nanowires in nanoelectronics and prospects for the future are discussed. Quasi-one-dimensional transport in conducting polymer nanowires A Aleshin doi:10.1134/S1063783407110017 Physics of the Solid State, Vol. 49, No. 11. (20 November 2007), pp. 2015-2033. 2008-01-16T14:08:44-00:00 2007 Physics of the Solid State 49 11 2015 2033 electronics organic polymer http://www.citeulike.org/user/skirnir/article/1676522 <i>Nature, Vol. 347, No. 6293. (11 October 1990), pp. 539-541.</i> Light-emitting diodes based on conjugated polymers JH Burroughes DDC Bradley AR Brown RN Marks K Mackay RH Friend PL Burns AB Holmes doi:10.1038/347539a0 Nature, Vol. 347, No. 6293. (11 October 1990), pp. 539-541. 2007-09-19T16:28:35-00:00 1990 Nature 347 6293 539 541 led polymer http://www.citeulike.org/user/skirnir/article/2301748 <i>Reviews of Modern Physics, Vol. 73, No. 3. (2001), 681.</i> Nobel Lecture: Semiconducting and metallic polymers: The fourth generation of polymeric materials Alan Heeger doi:10.1103/RevModPhys.73.681 Reviews of Modern Physics, Vol. 73, No. 3. (2001), 681. 2008-01-29T11:27:12-00:00 2001 Reviews of Modern Physics 73 3 681 American Physical Society doping polymer http://www.citeulike.org/user/skirnir/article/2370704 <i>Advanced Materials, Vol. 12, No. 22. (2000), pp. 1655-1668.</i><br /><br />Light-emissive polymers are outstanding laser materials because they are intrinsically ?4-level? systems, they have luminescence efficiencies higher than 60 % even in undiluted films, they emit at colors that span the visible spectrum, and they can be processed into optical quality films by spin casting. The important materials issues are reviewed and the prospects for making polymer diode lasers are discussed. Semiconducting (Conjugated) Polymers as Materials for Solid-State Lasers MD Mcgehee AJ Heeger doi:10.1002/1521-4095(200011)12:22<1655::AID-ADMA1655>3.0.CO;2-2 Advanced Materials, Vol. 12, No. 22. (2000), pp. 1655-1668. 2008-02-13T16:38:33-00:00 2000 Advanced Materials 12 22 1655 1668 laser polymer review http://www.citeulike.org/user/skirnir/article/2875519 <i>Journal of Electronic Materials, Vol. 37, No. 7. (15 July 2008), pp. 955-961.</i><br /><br />Abstract  Coating of ultralow-dielectric (ultralow-k) polymers on high-speed and high-frequency circuitries can increase signal propagation speed and reduce crosstalk. High-temperature foamed films have ultralow-k properties, but are ineffective in noise reduction because of the presence of dense skins. Vapor-induced phase separation was used to fabricate porous polyimide films in this investigation. Scanning electron microscopy revealed that the films are homogeneous without skin layers. The pore size can be controlled from less than a micron to several microns. Electrical characterization revealed that the relative dielectric constant is reduced to as low as 1.7 and is stable between 8.2 GHz and 18 GHz. Usage of this new ultralow-k material as a substrate can help to improve circuit speed by more than 40% compared to the dense Kapton substrate, making this material well suited for use in wide-band and high-frequency applications. Properties and Microstructures of Low-Temperature-Processable Ultralow-Dielectric Porous Polyimide Films Yuxing Ren David Lam doi:10.1007/s11664-008-0446-z Journal of Electronic Materials, Vol. 37, No. 7. (15 July 2008), pp. 955-961. 2008-06-09T11:56:32-00:00 2008 Journal of Electronic Materials 37 7 955 961 electronics fabrication polymer temperature http://www.citeulike.org/user/skirnir/article/731641 <i>Materials Today, Vol. 9, No. 4. (April 2006), pp. 24-30.</i><br /><br />Some of the major application areas for organic and polymeric transistors are reviewed. Organic complementary devices are promising on account of their lower power dissipation and ease of circuit design. The first organic large-scale integrated circuits have been implemented with this circuit approach. Organic transistor backplanes are ideally suited for electronic paper applications and other display schemes. Low-cost and other processing advantages, as well as improving performance, have led to organic-based radio frequency identification tag development. The chemical interaction between various organic and polymer semiconductors can be exploited in chemical and biological sensors based upon organic transistors. Organic and polymer transistors for electronics Ananth Dodabalapur doi:10.1016/S1369-7021(06)71444-4 Materials Today, Vol. 9, No. 4. (April 2006), pp. 24-30. 2006-07-03T02:11:00-00:00 2006 Materials Today 9 4 24 30 electronics organic polymer review http://www.citeulike.org/user/skirnir/article/2463974 <i>Macromolecules, Vol. 40, No. 21. (16 October 2007), pp. 7521-7531.</i><br /><br />Abstract: The poly(isocyanide) skeleton is shown to be a good support for assemblies of molecular units which permit p-type charge transport. A poly(isocyanide) containing tetrathiafulvalene (TTF) moieties in the side chains has been synthesized and characterized in its neutral state and has been oxidized to generate mixed valence states which display charge mobility in solution. UV-vis-NIR, EPR, and Raman spectroscopies were used to study the electronic properties of the polymer in its doped states, which were generated chemically with different oxidants. A broad charge-transfer band at 2100 nm characteristic of mixed valence agglomerations of neutral and cation radical TTFs was shown at lower doping levels, while evidence of aggregates between radical cation and the dicationic form of the heterocyclic system were seen at higher degrees of oxidation. The neutral macromolecule, the first mixed valence state, and the cation radical system can be reversibly interconverted by alternate oxidation with Fe(ClO4)3 and subsequent reduction with triethylamine, and therefore the material can be considered as a candidate for electrochromic switches. EPR measurements reveal magnetic interactions between cation radical TTF moieties as well as indication of charge delocalization over the macromolecule. Bearing in mind the steric impediment that the alkyl chains attached to the TTF unit provide, we conclude that the results suggest that the motion of the charges in the first mixed valence state is intramacromolecular: this hypothesis implies that there are interactions of the TTF residues in the side chains of the polymer which lead to a stack of the -functional units, confirming the affirmation that this polymer skeleton is appropriate for appending electron-conducting stacks of -functional units. Synthesis and Doping of a Multifunctional Tetrathiafulvalene- Substituted Poly(isocyanide) E Gomar-Nadal L Mugica J Vidal-Gancedo J Casado JTL Navarrete J Veciana C Rovira DB Amabilino doi:10.1021/ma0710986 Macromolecules, Vol. 40, No. 21. (16 October 2007), pp. 7521-7531. 2008-03-04T11:38:34-00:00 2007 Macromolecules 40 21 7521 7531 electronics organic polymer review ttf http://www.citeulike.org/user/skirnir/article/2302084 <i>Physical Review Letters, Vol. 39, No. 17. (24 October 1977), 1098.</i><br /><br />Doped polyacetylene forms a new class of conducting polymers in which the electrical conductivity can be systematically and continuously varied over a range of eleven orders of magnitude. Transport studies and far-infrared transmission measurements imply a metal-to-insulator transition at dopant concentrations near 1%. Electrical Conductivity in Doped Polyacetylene CK Chiang CR Fincher YW Park AJ Heeger H Shirakawa EJ Louis SC Gau Alan Macdiarmid doi:10.1103/PhysRevLett.39.1098 Physical Review Letters, Vol. 39, No. 17. (24 October 1977), 1098. 2008-01-29T13:21:54-00:00 1977 Physical Review Letters 39 17 1098 American Physical Society doping polymer http://www.citeulike.org/user/scis0000001/article/832427 <i>(9 Jul 1997)</i><br /><br />We explore and calculate the rich scaling behavior of copolymer networks in solution by renormalization group methods. We establish a field theoretic description in terms of composite operators. Our 3rd order resummation of the spectrum of scaling dimensions brings about remarkable features: The special convexity properties of the spectra allow for a multifractal interpretation while preserving stability of the theory. This behavior could not be found for power of field operators of usual $φ^4$ field theory. The 2D limit of the mutually avoiding walk star apparently corresponds to results of a conformal Kac series. Such a classification seems not possible for the 2D limit of other copolymer stars. We furthermore provide a consistency check of two complementary renormalization schemes: epsilon expansion and renormalization at fixed dimension, calculating a large collection of independent exponents in both approaches. Copolymer Networks and Stars: Scaling Exponents Christian von Ferber Yurij Holovatch (9 Jul 1997) 2006-09-06T14:19:45-00:00 1997 criticality polymer scaling-exponent star universality http://www.citeulike.org/user/sas/article/2147370 <i>Science, Vol. 295, No. 5564. (29 March 2002), pp. 2407-2409.</i><br /><br />10.1126/science.1067794 Functional Materials Based on Self-Assembly of Polymeric Supramolecules Olli Ikkala Ten doi:10.1126/science.1067794 Science, Vol. 295, No. 5564. (29 March 2002), pp. 2407-2409. 2007-12-19T16:52:48-00:00 2002 Science 295 5564 2407 2409 assembly functional polymer self http://www.citeulike.org/user/sas/article/1698390 <i>Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 74, No. 4. (2006)</i><br /><br />We present a method to investigate the dynamics of a single semiflexible polymer, subject to anisotropic friction in a viscous fluid. In contrast to previous approaches, we do not rely on a discrete bead-rod model, but introduce a suitable normal mode decomposition of a continuous space curve. By means of a perturbation expansion for stiff filaments, we derive a closed set of coupled Langevin equations in mode space for the nonlinear dynamics in two dimensions, taking into account exactly the local constraint of inextensibility. The stochastic differential equations obtained this way are solved numerically, with parameters adjusted to describe the motion of actin filaments. As an example, we show results for the tumbling motion in shear flow. Dynamics of semiflexible polymers in a flow field Tobias Munk Oskar Hallatschek Chris Wiggins Erwin Frey doi:10.1103/PhysRevE.74.041911 Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 74, No. 4. (2006) 2007-09-26T21:40:09-00:00 2006 Physical Review E (Statistical, Nonlinear, and Soft Matter Physics) 74 4 APS flow mode normal polymer semiflexible http://www.citeulike.org/user/sas/article/2147360 <i>Science, Vol. 277, No. 5330. (29 August 1997), pp. 1225-1232.</i><br /><br />10.1126/science.277.5330.1225 Competing Interactions and Levels of Ordering in Self-Organizing Polymeric Materials M Muthukumar CK Ober EL Thomas doi:10.1126/science.277.5330.1225 Science, Vol. 277, No. 5330. (29 August 1997), pp. 1225-1232. 2007-12-19T16:49:56-00:00 1997 Science 277 5330 1225 1232 assembly organization polymer self http://www.citeulike.org/user/sas/article/1698375 <i>Nat Mater, Vol. 3, No. 8. (2004), pp. 564-568.</i> Flow-induced properties of nanotube-filled polymer materials Semen Kharchenko Jack Douglas Jan Obrzut Eric Grulke Kalman Migler doi:10.1038/nmat1183 Nat Mater, Vol. 3, No. 8. (2004), pp. 564-568. 2007-09-26T21:30:10-00:00 2004 Nat Mater 3 8 564 568 cnt polymer http://www.citeulike.org/user/sas/article/2147069 <i>Interphases and Mesophases in Polymer Crystallization III (2005), pp. 241-274.</i><br /><br />We summarize the salient conclusions derived from Langevin dynamics simulations of many flexible polymer molecules undergoing crystallization from solutions. These simulations reveal molecular mechanisms of nucleation and growth, and the accompanying free energy barriers, during the very early stages of crystallization. The simulation results are also analyzed by statistical mechanics theories. Major conclusions on the growth of density fluctuations in the primordial stage, birth of baby nuclei, which then mature into lamellae through a stage of smectic pearls, and spontaneous selection of finite equilibrium lamellar thickness are addressed. Furthermore, selection of shapes is addressed using a novel Monte Carlo algorithm for polymer crystallization in solutions. In addition, details of free energy landscape just in front of the growth front are summarized, based on Langevin dynamics simulations. The mechanism of growth is seen to be an adsorption process, in contrast to previous beliefs. Finally, the role of externally imposed flow on polymer crystallization is addressed by considering the molecular mechanisms behind the formation of shish-kebab morphology in extensional flows. The major conclusions from the reviewed simulation results are qualitatively different from the established models of polymer crystallization. Modeling Polymer Crystallization M Muthukumar doi:10.1007/12_008 Interphases and Mesophases in Polymer Crystallization III (2005), pp. 241-274. 2007-12-19T15:11:25-00:00 2005 Interphases and Mesophases in Polymer Crystallization III 241 274 crystallization modeling polymer http://www.citeulike.org/user/sas/article/2091579 <i>The Journal of Chemical Physics, Vol. 107, No. 24. (1997), pp. 10793-10798.</i><br /><br />  Long-lived interchain contacts in polymer melts Grzegorz Szamel Tian Wang The Journal of Chemical Physics, Vol. 107, No. 24. (1997), pp. 10793-10798. 2007-12-11T21:29:42-00:00 1997 The Journal of Chemical Physics 107 24 10793 10798 AIP bfm entanglement melt polymer http://www.citeulike.org/user/sas/article/2802678 <i>Macromolecules, Vol. 37, No. 24. (30 November 2004), pp. 9048-9055.</i><br /><br />Abstract: Single-walled carbon nanotube (SWNT)/poly(methyl methacrylate) (PMMA) nanocomposites were prepared via our coagulation method providing uniform dispersion of the nanotubes in the polymer matrix. Optical microscopy, Raman imaging, and SEM were employed to determine the dispersion of nanotube at different length scales. The linear viscoelastic behavior and electrical conductivity of these nanocomposites were investigated. At low frequencies, G' becomes almost independent of the frequency as nanotube loading increases, suggesting an onset of solidlike behavior in these nanocomposites. By plotting G' vs nanotube loading and fitting with a power law function, the rheological threshold of these nanocomposites is ~0.12 wt %. This rheological threshold is smaller than the percolation threshold of electrical conductivity, ~0.39 wt %. This difference in the percolation threshold is understood in terms of the smaller nanotube-nanotube distance required for electrical conductivity as compared to that required to impede polymer mobility. Furthermore, decreased SWNT alignment, improved SWNT dispersion, and/or longer polymer chains increase the elastic response of the nanocomposite, as is consistent with our description of the nanotube network. Nanotube Networks in Polymer Nanocomposites: Rheology and Electrical Conductivity F Du RC Scogna W Zhou S Brand JE Fischer KI Winey doi:10.1021/ma049164g Macromolecules, Vol. 37, No. 24. (30 November 2004), pp. 9048-9055. 2008-05-15T20:58:09-00:00 2004 Macromolecules 37 24 9048 9055 nanocomposite nanotube polymer rheology