Thermodynamic and electro-optic characteristics of UV-cured monofunctionalacrylate/nematic liquid crystal mixtures

Polymer Dispersed Liquid Crystals (PDLC) were prepared via a Polymerization Induced Phase Separation (PIPS) mechanism using U.V. radiation. The sample s were obtained from the liquid crystalline mixture E7 and a monofunctional monomer (Ethylene Glycol Phenyl Ether Acrylate). The thermodynamic propert ies of cured samples were studied by Differential Scanning Calorimetry (DSC ). The LC solubility limit in the polymer matrix, A, and the fractional amo unt of LC contained in the droplets, alpha, were determined (A=20 wt-%; alp ha=0.76 for 50 wt-% LC). The electro-optic characteristics of the PDLC film s were investigated as a function of the LC composition and of the amplitud e of the applied voltage. For a series of PDLC films with different thickne sses, the droplet distributions and the droplets densities were found nearl y identical.