Formation of a host nanostructure for ferroelectric liquid crystals using thiol-ene polymers

Abstract

Liquid crystal displays are a subject of intense research interest because of their application to high definition display devices. Recently, polymer stabilized ferroelectric liquid crystals (PSFLCs) have been investigated due to the enhanced electro-optic properties of FLCs. We have utilized thiol-ene photopolymerizations to form a PSFLC system. Thiol-ene photopolymerizations are radical reactions, which proceed via a step growth reaction mechanism. During the polymerization, the polymer network structure is trapped into place due to the rapid transition from low molecular mass monomers and oligomers to high molecular mass polymer. This aspect is evidenced by phase transition data for the FLC, which indicates that the monomer and polymer are not phase separated from the FLC. Infrared dichroism shows that both monomer and polymer are ordered in parallel with the smectic layers of the FLC. Small angle X-ray scattering (SAXS) data show that both monomer and polymer are swelling the smectic layers. Thus, a polymer nanostructure is produced that serves as an ordered, stabilizing host for the FLC.