Experimental study of prewetting transitions by systematic variation of the surface field at nematic liquid crystal/water interfaces

Max Planck Institute for Dynamics and Self-Organization - Bunsenstr. 10, D-37073 Göttingen, Germany, EU

Corresponding author: christian.bahr@ds.mpg.de

Received: 7 October 2009
Accepted: 6 November 2009

Abstract

An ellipsometric study of the interface between a nematic liquid crystal and water in the presence of a nonionic surfactant is presented. The surfactant induces a nematic wetting layer at temperatures above the bulk nematic-isotropic transition and the surfactant concentration serves as a handle to tune the strength of the ordering surface field. At low surfactant concentrations, a discontinuous jump in the thickness of the nematic wetting layer is observed at a temperature a few tenth of one centigrade above the bulk nematic-isotropic transition. With increasing surfactant concentration, this prewetting transition is driven towards a critical point.