Effect of molecular weight of monomer on the processes of phase separation during the elaboration of composite materials type PDLC

Abstract

Polymer Dispersed Liquid Crystals (PDLC) were elaborated by polymerization induced phase separation under ultraviolet (UV). A binary systems use in this study is composed of monomer of different molecular weights (TPGDA, PPGDA540 and PPGDA900), and 70 Wt.% of liquid crystal 5CB. The results showed a rapid decrease of the transmission of the LC droplet formation, followed by an enhancement of the transmission due to a thermal effect generated by exothermic curing, thermal diffusivity between components of the mixture monomers / LC, IR spectrum and high intensity of UV radiation emitted by LC3 lamp. PDLC films prepared exhibit different morphologies depending on the composition of the initial mixture, the UV dose, the molecular weight of the monomer and the nature of a LC. To quantify the effect of the molecular weight of the monomer on the kinetics of phase separation of the reactive mixtures, we realized a theoretical study that has given us a good accord with experiment.