Rollable ferroelectric liquid crystal devices monostabilized with molecularly aligned polymer walls and networks

摘要

This paper describes a flexible monostabilized ferroelectric liquid crystal (FLC) device using molecularly aligned polymer walls and networks, which are sequentially formed with a two-step photopolymerization-induced phase separation. When ultraviolet (UV) light was irradiated through a photomask onto a heated nematic phase solution of FLC and monomer, monomer molecules that had flowed into the irradiated areas were photopolymerized, and polymer walls aligned along the rubbing direction of the polyimide alignment layers on plastic film substrates were formed. After uniform UV irradiation without a photomask, polymer networks aligned along the rubbing direction were formed in the FLC. The FLC molecules were monostabilized in the rubbing direction by the strong anchoring of the polymer networks. The device, which was sandwiched between crossed polarizers, exhibited a monostable electro-optic characteristic with a high contrast ratio of over 100:1 and a response time of less than 1 ms. The FLC device exhibited spatially uniform operation even when it was rolled up with a radius of curvature of 1.5 cm.