PDLC based on unsaturated polyester resins: molecular, morphological and thermo-optical analysis

A thermosetting matrix based on an unsaturated polyester resin was employed to realise a Polymer Dispersed Liquid Crystal (PDLC) system by a UV induce d curing process. A molecular, morphological and thermo-optical characteris ation of this system is presented. The chemical and structural properties w ere investigated by transmission FT-IR spectra in the near infrared frequen cy range and by dynamic-mechanical analysis. The results indicated that, up on curing, the matrix retains its intrinsic properties even for composition s very rich in the LC component (40 wt %). The morphology, investigated by optical and electron microscopy, showed phase separation before and after t he curing process. Image analysis demonstrated that the cured materials had morphological features suitable to achieve interesting thermo-optical prop erties. In particular, the composition containing 40 wt % of LC exhibited t he typical behaviour of a thermo-optical switch. Interesting optical bistab ility effects were also demonstrated for this particular composition. (C) 2 000 Kluwer Academic Publishers.