PHASE-BEHAVIOR AND ELECTROOPTIC CHARACTERISTICS OF A POLYMER STABILIZED FERROELECTRIC LIQUID-CRYSTAL

The effects of adding a diacrylate monomer or its polymerized network to a ferroelectric liquid crystal have been characterized. The monomer lowers the temperatures of transition to the more ordered phases, whe reas the polymer network phase separates into polymer rich and LC rich phases and has Little effect on the LC phase behaviour. Ferroelectric polarization decreases comparably in both monomer and networked syste ms. As the network concentration increases, the size of LC domains dec reases considerably. With low concentrations of polymer and, thus larg e LC domains, optical response and tilt angle remain fairly independen t of polymer concentration, but as the polymer concentration increases , switching speed and tilt angle decrease dramatically. Polymerization rate maxima increase with monomer concentration until saturation of m onomer in the liquid crystal is reached. The rate maxima then decrease as monomer must diffuse from monomer rich droplets. Double bond conve rsion during the polymerization is comparable for all monomer concentr ations below 50 per cent.