Adsorption-induced anchoring transitions at nematic-liquid-crystal–crystal interfaces

Discontinuous (first-order) anchoring transitions are shown to occur as a function of water adsorption at the nematic-liquid-crystal(E9)--gypsum and E9-mica interfaces. The transitions involve growth of domains with an anchoring a' making a finite angle with the direction a of the parent anchoring. The growth proceeds by motion of walls separating the domains with the new anchoring a' from the matrix with the parental anchoring a. A Landau-type expression for the interfacial energy is proposed and used to classify the anchoring transitions and to explain the behavior of the domains during the first-order anchoring transitions.