Inverse regime of ionic modification of surface anchoring in nematic droplets

Abstract

It was found that the effect of the ionic modification of anchoring in liquid-crystal droplets can be implemented in the inverse regime. Droplets of 4-n-pentyl-4′-cyanobiphenyl nematic doped with ionic cetyltrimethylammonium bromide surfactant were dispersed in polyvinyl alcohol and investigated. In the initial state, nematic droplets have a radial structure with homogeneous homeotropic anchoring typical of the surfactant used. In the presence of a dc electric field, the boundary conditions become tangential in the surface area left by the cations. That results in the transformation of an orientational structure following by various scenarios. For the new states of nematic droplets, the distribution of the director field was analyzed and the corresponding textural patterns were numerically calculated.