Translational Self-Diffusion Measurements and Analysis of a Calamitic Smectogen

Abstract

Translational self-diffusion measurements have been performed in the mesophases of the p-hexyloxybenzylidene-p'-fluoroaniline (FAB.OC6) liquid crystal, by means of a static fringe field gradient approach. The method provides an accurate enough data set of the diffusion tensor as a function of temperature in the nematic and smectic A phase to be used for accurate analysis exploiting well established selfdiffusion models. Also measurements in the smectic B phase have been carried out and the results obtained seem to be consistent with a picture where the out of plane diffusion is strongly inhibited ð< 10 À15 m 2 =sÞ and only a slow in plane diffusion ð$ 10 À13 m 2 =sÞ is present.