화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.261, 593-603, 1995
Liquid-Crystal Monomer Additives for Improved Polymer-Dispersed Liquid-Crystals
The performance of polymer dispersed liquid crystal (PDLC) films was improved markedly by introduction of a monofunctional liquid crystal monomer component into the photopolymerizable solution from which the PDLC was formed by phase separation. Small amounts of an LC-monomer additive enhanced the LC phase separation and slowed the rate of polymerization. Use of 1-10% of LC-monomer in the solution led to the formation of larger LC droplets in a less rigid polymer, resulting in PDLC films with lower threshold and operating voltages and increased the contrast ratio. The effects of LC-monomer additives on PDLC properties were studied as a function of their structure and concentration, particularly in a photopolymerizable solution of Norland NOA65 monomer system with BDH-E9. For example an optimized amount of LC-monomer, such as 4% p-butylphenyl p-acryloyloxybenzoate in a 1:1 solution of NOA65 and BDH-E9, gave 50% lower threshold and operating voltages, together with 9% higher on-state transmission than the PDLC films without the LC-monomer additive.