Effect of polymer structures on electro-optical properties of polymer stabilized liquid crystal films

Abstract

The polymer stabilized liquid crystal (PSLC) film is a relatively novel electro-optical material, which is generally obtained by dissolving a small amount of a bifunctional photoreactive monomer in a low molecular mass liquid crystal. In this paper, the PSLC films were prepared with photoreactive biphenyl methacrylate monomers by photopolymerization induced phase separation. The effects of liquid crystal concentration, curing time, monomer structures and alignment layer on the electro-optical properties of PSLC films were investigated. The results show that the transmittance in the OFF state (T_OFF) increased with the liquid crystal concentration, but the driving voltage decreased. T_OFF was also influenced by the curing time. Furthermore, when polyimide was used as alignment layer, the films prepared from the bifunctional monomer shows a higher T_OFF, while those from the single functional monomer exhibited a deformed electro-optical curve due to the unsteady polymer networks.

Keywords

polymer network / liquid crystal / network morphology / electric-optical properties