Studies of a Polymer Dispersed Ferroelectric Liquid Crystal

Abstract

Ferrorlrtric liquid crystals (FLCs) have shown great potential for use in electro-optic and display technology due to theri inherently fast switching speeds. Recently within this area a great deal of attention has also been given to FLCs dispersed within a polymer networks. Adding the polymer may act to enhance certain electro-optic properties and will substantially increase the mechanical strenth on the FLC system. This study examines the effects of adding either a diacrylate monomer or a polymer network to a FLC mixture of known composition. The monomer depresses the phase transition temperatures to more orderd phases for both first and second order transitions and causes a marked decrease in the amount of liquid crystal which exhibits typical transitions behavior. During polymerization the network phase separates forming two cocontinuous phases and allows the liquid crystal transitions to return close to values seen in polymer systems. As a result of this decrease, the rotational viscosity decrease for these same samples. Maximum double bond conversions and polymerization rate maxima increase with monomer concentration until saturation on monomer in the liquid crystal is reached. The rate maxima then decreases as the monomer as the monomer must dissolute into the liquid crystal and diffuse to the reactive sites.