Issue
EPL
Volume 88, Number 4, November 2009
Article Number 46001
Number of page(s) 6
Section Condensed Matter: Structural, Mechanical and Thermal Properties
DOI http://dx.doi.org/10.1209/0295-5075/88/46001
Published online 02 December 2009
EPL, 88 (2009) 46001
DOI: 10.1209/0295-5075/88/46001

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

Ch. Bahr

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

christian.bahr@ds.mpg.de

received 7 October 2009; accepted in final form 6 November 2009; published November 2009
published online 2 December 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.

PACS
61.30.-v - Liquid crystals.
61.30.Hn - Surface phenomena: alignment, anchoring, anchoring transitions, surface-induced layering, surface-induced ordering, wetting, prewetting transitions, and wetting transitions.
68.05.Cf - Liquid-liquid interface structure: measurements and simulations.

© EPLA 2009