The cholesteric-nematic transition in droplets subjected to electric fields

Abstract

We have observed the behaviour of chiral nematic droplets with positive dielectric anisotropy subjected to electric fields. With increasing field, the Frank-Pryce spherulitic director configuration is distorted progressively into a quasi-cylindrical spiral twist wall. As the field increases further this wall progressively unwinds, resulting in a confined cholesteric-nematic transition. Measurements of the pitch versus electric field show that, despite the confinement, the pitch is still described by the theory for the unconfined cholesteric-nematic transition.