Effect of Ordering on Spinodal Decomposition of Liquid-Crystal/Polymer Mixtures

Partially phase-separated liquid-crystal/polymer dispersions display highly fibrillar domain morphologies that are dramatically different from the typical structures found in isotropic mixtures. To explain this, we numerically explore the coupling between phase ordering and phase separation kinetics in model two-dimensional fluid mixtures phase separating into a nematic phase, rich in liquid crystal, coexisting with an isotropic phase, rich in polymer. We find that phase ordering can lead to fibrillar networks of the minority polymer-rich phase

Studies of adsorption-entanglement layers and high-modulus, high-strength tapes and fibres of polyethylene

SIGLEAvailable from British Library Document Supply Centre- DSC:D66844/86 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Energy transfer in hybrid quantum dot light-emitting diodes

Energy transfer in a host-guest system consisting of a blue-emitting poly(2,7-spirofluorene) (PSF) donor and red-emitting CdSe/ZnS core shell quantum dots (QDs) as acceptor is investigated in solid films, using time-resolved optical spectroscopy, and in electroluminescent diodes. In the QD:PSF composite films, the Förster radius for energy transfer is found to be 4–6 nm. In electroluminescent devices lacking an electron transport layer, the electroluminescence (EL) spectrum of the QD:PSF polymer composite is similar to the photoluminescence (PL), giving evidence for energy transfer from PSF to the QDs. The addition of an electron transport layer between the emitting layer and the cathode results in a significant change in the EL spectrum and a considerable improved device performance, providing almost pure monochromatic emission at 630 nm with a luminance efficiency of 0.32 cd/A. The change in spectrum signifies that the electron transport layer changes the dominant pathway for QD emission from energy transfer from the polymer host to direct electron-hole recombination on the QDs

Linear polarizers based on oriented polymer blends

Linear sheet polarizers based on the anisotropic scattering of light by drawn polymer blends are introduced here. The proper selection of materials and processing conditions for the production of large-area, flexible films of phase-segregated polymer blends suitable for polarization applications are discussed. The Figure shows an SEM micrograph of a fracture surface of such a polymer blend

Linear polarizers based on polymer blends : oriented blends of poly(ethylene-2,6-naphthalene-dicarboxylate) and a poly(styrene/methyl-methacrylate) copolymer

\u3cp\u3eThe optical properties of linear polarizers based on blends of poly(ethylene-2,6-naphthalenedicarboxylate) and a poly(styrene/methylmethacrylate) copolymer are presented. In the oriented blends, the refractive index of the dispersed phase is matched with the ordinary refractive index of the birefringent continuous phase while, a large refractive index mismatch is simultaneously generated in the perpendicular direction. The films are therefore transparent or opaque depending on the polarization direction of the incident light and act as a linear polarizer. In the non transparent state, the incident light is mainly scattered in the backward direction (+80%), which potentially enhances the yield of transmitted polarized light if the backscattered light is recycled in a suitable device. This latter feature is useful, for instance, in display applications where a high brightness or energy efficiency is desired.\u3c/p\u3