Electric Field-Induced Deformations in Oriented Liquid Crystals of the Nematic Type

Abstract The influence of an electric field on nematic liquid crystals is investigated for several orientations of the liquid crystal. We give a theoretical treatment of the normal deformation that arises from the interaction of the electric field with the dielectric anisotropy. Our experimental deformations show relatively good agreement with the calculated values. Some anomalous deformations were also investigated. Conditions and threshold voltages for Williams domains are discussed. If the undisturbed optical axis is parallel to the applied electric field and the dielectric anisotropy is positive, no Williams domains appear. This result is in agreement with the Carr-Helfrich model.