FTIR AND UV-VISIBLE SPECTROSCOPY STUDIES OF THIOL-ENE/E7 COMPOSITES SHOWING NANODISPERSIONS: CURING KINETICS AND ELECTRO-OPTICAL PROPERTIES

摘要

Polymer Dispersed Liquid Crystals exhibiting nanosized droplet dispersions and prepared from thiol-ene monomer/E7 liquid crystal systems were investigated. Photocured samples were prepared according to the method of polymerization induced phase separation using a standard halogen bulb light source in the presence of photoinitiators. FTIR spectroscopy was used to study the kinetics of polymerization by monitoring the rate of conversion of the thiol S-H bond at 2570 cm~(-1) and the allylic double bond C = C at 1647 cm~(-1). With the help of UV-visible spectroscopy, we investigated the spectral transmission of these materials as a function of composition and curing conditions. A Fabry-Perot cell was used to explore the reflection properties in the unaddressed and addressed states. A shift in the interferometric pattern corresponding to an increase in the material birefringence was found and analysed in terms of the field strength and frequency.