Electric field effects on the droplet structure in polymer dispersed cholesteric liquid crystals

Abstract

The behaviour of polymer dispersed cholesteric droplets in electric fields has been investigated for materials with both negative and positive dielectric anisotropy. Microscopic observations parallel and perpendicular to the electric field were performed. In materials with ε_a < 0, the cholesteric pitch remains constant but a disclination ring occurs due to reorientation of the local helix directions. In systems with ε_a > 0, however, helical unwinding was observed.