Abstract
Optically transparent and isotropic liquid crystalline composites were successfully prepared by in-situ photo-polymerization of cross-linking monomers in the isotropic phase of chiral liquid crystals. The electro-optical Kerr constant of the composite steeply increased with decreasing temperature in accordance with a pretransitional behavior expressed by the Landu-de Gennes theory in a temperature range of the isotropic phase. This is due to thermal growth of the coherence length of short-range orientational order of the liquid crystal molecules. Even in a temperature range below the critical temperature where the coherence length grows infinitely and the Kerr effect originating from the pretransitional phenomenon disappears in case of common nematics, the composite showed the remarkable Kerr effect being relatively insensitive to temperature. The results indicate that the growth of the coherence length was effectively suppressed by polymer network and chirality of the liquid crystals below the critical temperature.
