Recently a surface transition driven by the temerature in nematics has been observed and discussed [K. Flatischler et al., Mol. Cryst. Liq. Cryst. 198, 119 (1991)]. Such a transition usually appears some degrees below the clearing point: it consists of a change of alignment in the whole nematic layer, from homeotropic to planar, on heating. The transition could be second or first order, depending on surface treatment and bulk properties and is reversible: in the latter case hysteresis takes place. The importance of such a phenomenon is evident, since the temerature surface transition affects the electro-optical properties of a nematic cell. Here we present a new Landau-de Gennes model describing the surface transition which occurs when the cell walls, covered by a thin layer of silicon monoxide, are dipped in a very dilute solution of egg-lecithin in chloroform.
|Titolo:||A Landau - de Gennes model for the temperature surface transition in nematics|
|Data di pubblicazione:||1994|
|Digital Object Identifier (DOI):||10.1080/10587259408027206|
|Appare nelle tipologie:||1.1 Articolo in rivista|