Surfactant-induced nematic wetting layer at a thermotropic liquid crystal/water interface.
An ellipsometric study of the interface between a thermotropic liquid crystal and water near the nematic-isotropic phase transition of the liquid crystal is presented. At temperatures above the transition, a nematic wetting layer appears at the interface if the water phase contains a surfactant inducing a homeotropic alignment of the nematic phase. The detailed behavior is significantly influenced by the concentration of the surfactant. The results can be described by a Landau model of nematic wetting in which the surfactant concentration tunes the magnitude of an ordering interface potential.
Bahr
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Max Planck Institute for Dynamics and Self-Organization, Bunsenstrasse 10, D-37073 Göttingen, Germany. christian.bahr@ds.mpg.de