Control of the orientation of thin open supported columnar liquid crystal films by the kinetics of growthEric Grelet and Harald Bock
Centre de Recherche Paul Pascal, CNRS UPR 8641, Université Bordeaux 1 115 avenue Albert Schweitzer, F-33600 Pessac, France
received 26 October 2005; accepted in final form 10 January 2006
published online 1 February 2006
We report a study of the growth and of the orientation of thin open supported columnar liquid crystal films by thermal annealing. We show that there is a competition between planar and homeotropic orientations (columns respectively oriented parallel and perpendicular to the solid substrate) of the liquid crystal, which can be controlled by the kinetics of annealing. A model based on the different surface tensions of the system is proposed to account for the experimental observations. Such a control of the alignment opens the way towards discotics based optoelectronic devices.
61.30.Hn - Surface phenomena: alignment, anchoring, anchoring transitions, surface-induced layering, surface-induced ordering, wetting, prewetting transitions, and wetting transitions.
64.70.Md - Transitions in liquid crystals.
68.55.-a - Thin film structure and morphology.
© EDP Sciences 2006