Eur. Phys. J. B 1, 327-331 (1998)
https://doi.org/10.1007/s100510050190

Effect of surface electric field on the anchoring of nematic liquid crystals

¹ Dipartimento di Fisica del Politecnico and Istituto Nazionale della Materia Corso Duca degli Abruzzi 24, 10129 Torino, Italia
² Departamento de Fisica, Universitade Estadual de Maringa, Avenida Colombo 3690, 87020-900, Maringa, Parana, Brazil
³ Raman Research Institute, C.V. Raman Avenue, Bangalore 560 080, India

Corresponding author: ^a barbero@polito.it

Received: 29 September 1997
Accepted: 18 November 1997
Published online: 15 February 1998

Abstract

We analyse the influence of adsorbed ions and the resulting surface electric field and its gradient on the anchoring properties of nematics with ionic conductivity. We take into account two physical mechanisms for the coupling of the nematic director with the surface electric field: (i) the dielectric anisotropy and (ii) the coupling of the quadrupolar component of the flexoelectric coefficient with the field gradient. It is shown that for sufficiently large fields near saturated coverage of the adsorbed ions, there can be a spontaneous curvature distortion in the cell even when the anchoring energy is infinitely strong. We also discuss the director distortion when the anchoring energy of the surface is finite.