The Electric Field in Polymer Dispersed Liquid Crystal Droplets and its Influence on Molecular Orientation

Abstract

We derived the expression for the electric field in an isolated spherical droplet of a uniformly oriented uniaxial liquid crystal contained within an isotropic medium, as a function of the dielectric and conductive properties of the materials and of the orientation of the liquid crystal. Results show that the field within the droplet is uniform and that its direction is different from the one of the applied field. Above a certain threshold field intensity the liquid director is reoriented but this simultaneously lowers the field in the droplet. This mechanism contributes to the lack of sharpness in the electrooptic response of PDLC's to an applied field and it must be considered together with the other already known mechanisms. This effect plays a negative role in multiplex addressing applications of PDLC films.

Key Words:

• Liquid crystals
• PDLC