Thermodynamic and Electro-Optic Characteristics of UV-Cured Monofunctional Acrylate/Nematic Liquid Crystal Mixtures

Polymer Dispersed Liquid Crystals (PDLC) were prepared via a Polymerization Induced Phase Separation (PIPS) mechanism using U.V. radiation. The samples were obtained from the liquid crystalline mixture E7 and a monofunctional monomer (Ethylene Glycol Phenyl Ether Acrylate). The thermodynamic properties of cured samples were studied by Differential Scanning Calorimetry (DSC). The LC solubility limit in the polymer matrix, A, and the fractional amount of LC contained in the droplets, α, were determined (A=20 wt-% α=0.76 for 50 wt-% LC). The electro-optic characteristics of the PDLC films were investigated as a function of the LC composition and of the amplitude of the applied voltage. For a series of PDLC films with different thicknesses, the droplet distributions and the droplets densities were found nearly identical.