Nanostructured Polymer Dispersed Liquid Crystals Using a Ferroelectric Smectic a Liquid Crystal

Nanostructured polymer dispersed liquid crystals (nano-PDLCs) are transparent and optically isotropic materials, in which submicron-sized liquid crystal (LC) domains are dispersed within a polymer matrix. Nano-PDLCs can induce their birefringence by applying an electric field (E-field) based on reorientation of LC molecules. If nano-PDLCs are utilized as light scattering-less birefringence memory materials, it is necessary to suppress the relaxation of LC molecules orientation after removal of the E-field. We focused on a ferroelectric smectic A (SmA) to suppress the relaxation of LC molecules due to their layered structure and high viscosity. Although nano-PDLCs require a strong E-field to reorient LC molecules due to the anchoring effect on the LC/polymer interface, the required field strength can be reduced by using a ferroelectric smectic A (SmAF) LC with a large dielectric constant. In this study, we fabricated a nano-PDLC by irradiating an ultraviolet light to a mixture comprising of a SmAF LC, photocurable monomers and a photo-initiator and its electro-birefringence effect was evaluated using a polarizing optical microscopy. After removal of an E-field, enhanced memory effect was observed on the sample using SmAFLC comparing to nematic LC based nano-PDLCs. (193 words/ 200 words)