2019 Impact factor 1.812
Soft Matter and Biological Physics

Eur. Phys. J. E 3, 123-130

Surface electric-field-induced instabilities in a homeotropically oriented nematic liquid crystal sample

H.A. Pereira - L.R. Evangelista

Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo 5790, 87020-900 Maringá, Paraná, Brazil
luiz.evangelista@cybertelecom.com.br

Received 4 November 1999 and Received in final form 4 April 2000

Abstract
The effect of a surface electric field produced by ionic adsorption on the molecular orientation of a nematic liquid crystal sample is analyzed. The eigenvalue problem for a semi-infinite medium is analytically solved both for strong and weak anchoring situations. The threshold instabilities are numerically determined and it is shown that the homeotropic pattern can be destabilized also in the situation of strong anchoring. The dependence of the threshold field on the anchoring strength and on the surface polarization is determined by taking into account also the coupling of the quadrupolar component of the flexoelectric coefficient with the field gradient.

PACS
61.30.-v Liquid crystals - 61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order - 64.70.Md Transitions in liquid crystals

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