Eur. Phys. J. E 7, 175-182 (2002)
DOI: 10.1140/epje/i200101098
An anchoring transition at surfaces with grafted liquid-crystalline chain molecules
H. Lange1, 2 and F. Schmid11 Fakultät für Physik, Universität Bielefeld, 33615 Bielefeld, Germany
2 Institut für Physik, Universität Mainz, 55099 Mainz, Germany
schmid@physik.uni-bielefeld.de
(Received 5 July 2001 and Received in final form 16 November 2001)
Abstract
The anchoring of nematic liquid crystals on surfaces with grafted liquid-crystalline
chain molecules is studied by computer simulations and within
a mean-field approach. The computer simulations show that a swollen layer
of collectively tilted chains may induce untilted homeotropic
(perpendicular) alignment in the nematic fluid.
The results can be understood within a simple theoretical model.
The anchoring on a layer of mutually attractive chains is determined
by the structure of the interface between the layer of chain molecules and
the solvent. It is controlled by an interplay between the attractive chain
interactions, the translational entropy of the solvent and its elasticity.
A second-order anchoring transition driven by the grafting density
from tilted-to-homeotropic alignment is predicted.
61.30.Hn - Surface phenomena: alignment, anchoring, anchoring transitions, surface-induced layering, surface-induced ordering, wetting, prewetting transitions, and wetting transitions.
61.30.Vx - Polymer liquid crystals.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2002
