Expansion of temperature range of liquid crystalline frustrated phase

点击翻译按钮获取中文摘要

Preparation condition for stabilizing the polymer-stabilized blue phases which show liquid crystalline blue phase in a wide temperature range has been investigated. It becomes clear that the binary mixture of a monoacrylate monomer and a diacrylate monomer is required to stabilize the blue phase by isothermal photo-polymerization method. The photo-polymerization for preparing the polymer-stabilized blue phases was necessary to be carried out in the temperature range of the blue phase.Stabilizing the blue phase II, which is more difficult to stabilize than blue phase I, by photo-polymerization was conducted in a accuracy of temperature within 0.1 degree Celsius. High polymer-stabilizing effect of blue phase II was attained for the first time when the photo-polymerization was made within 0.3 degree Celsius in the temperature range of blue phase II.The blue phases possess great potential because of their unique characteristics, such as fast electrio-optical response, electrically controllable Bragg diffraction of visible light and a photonic band. We found that the response is much faster, the order of 10-100 micro-second on the rise and decay processes at room temperature and the zero-electric field state is optically isotropic unlike nematic phases, that is, no surface treatment (no rubbing) is necessary, leading to a simplification of the fabrication process. We also demonstrate the sufficiently large electric field-induced birefringence and the micro-second response of the polymer-stabilized blue phases without any surface treatment. Thus the polymer-stabilized blue phase has been shown to possess excellent properties which will contribute toward providing new liquid crystal displays with high quality and low cost.