Cover:The picture on the cover shows a large crowded bottle-brush polymer (top left) with anisotropic excluded volume scaling (top right) and a bottle brush copolymer (bottom right) exhibiting local phase separation showing 1d correlation length behavior (bottom left). Further details can be found in the article by H.-P. Hsu*, W. Paul, and K. Binder on page 660. Contents ReviewCurrently there is significant interest in the use of polymer-dispersed liquid crystals in display materials. Monte Carlo simulations have been used to study PDLCs in a variety of physical situations by different research groups. This article reviews present and past simulation studies of PDLCs. Different molecular simulation techniques applied to such systems are reviewed, along with the new key findings of bulk phase transitions. Some newly developed techniques (e.g., phase separation behavior) in PDLCs are also reported. New directions for future developments in PDLC research are also highlighted.

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ABSTRACT:The recent studies deal with a diblock copolymer, polystyrene-poly(ethylene oxide). Infrared spectroscopy, proton resonance spectroscopy ( 1 H-NMR), and laser light scattering techniques have been used to characterize the polymer. It has been concluded that the sample investigated is diblock copolymer polystyrene-poly(ethylene oxide) having molecular mass 1.656 Â 10 4 g/mol and blocks ratio 1 : 2. The micellization behavior is explored through 1 H-NMR, laser light scattering, light absorption, surface tension, and conductance and viscosity measurements. The results conclude that the critical micelles concentration of copolymer is 0.0951 g/dL at 25 C. It has been observed that the surface tension of solution decreases with the temperature and its impact is maxima in dilute concentration region. In addition, new methodologies have been introduced to get accurate critical micelles concentration and critical micelles temperature.

Molecular dynamics (MD) computer simulation techniques, as a powerful tool commonly utilized by the liquid crystal display (LCD) community, usually are employed for computing the equilibrium and transport properties of a classical many body system, since they are very similar to real experiments in many respects. In this paper we present molecular dynamics computer simulation results taken for a mixture of the two different kinds of nematic liquid crystals (LCs). We calculated rotational viscosity from Brownian behavior with friction of the mean director of the mixture comprising pentylcyanobiphenol (5CB) and decylcyanobiphenol (10CB) by using molecular dynamics computer simulation, where intermolecular potential parameter is Generalized AMBER force field (GAFF). Our computed results show a good agreement with the experimental results.

2008) Synthesis and properties of non-symmetric liquid crystal dimers containing a cholesteryl moiety, Liquid Crystals, 35:1, 39-44, A series of non-symmetric liquid crystal dimers having cholesteryl and 4-trans-(4-nalkylcyclohexyl)phenoxy groups were synthesized by condensation of cholesteryl vbromoalkanoates with appropriate 4-trans-(4-n-alkylcyclohexyl)phenols. The structures and thermal phase behaviour of the dimers were characterized using IR, 1 H NMR and mass spectroscopy, elemental analysis, differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction measurements. Their thermal phase behaviour is significantly different to that of other cholesterol-based liquid crystal dimers. All of these liquid crystal dimers exhibit low phase transition temperatures. The relationships between their properties and chemical structures of these new dimers are discussed.

Acrylic polyethylene glycol(PEG)-based polymer-dispersed liquid crystal (PDLC) films have been fabricated to investigate the effect of intermolecular interactions on PDLC performance. For this purpose, the amphiphilic liquid crystal and polymers are selected as PDLC composite materials. The acrylic PEG contents are varied from 0 to 66.66 mol wt.% in order to understand the effects of different levels of additions on the microstructure and electro-optical properties of the PDLC films. For this intention, polarized optical microscopy and UV-vis spectroscopy are used. The extent of phase separation and anchoring energy are also examined using Fourier transform infrared (FTIR) spectroscopy and contact angle measurements in consequence of acrylic PEG addition. The contrast ratio, threshold voltage, as well as saturation voltage, tended to increase with the addition of acrylic PEG. The molecular affinity involved in the polymer matrix and LC molecules affected the phase separation which is responsible for the formation of domain size; this accordingly changed the electro-optical properties of PDLC film.

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