J. Physique Lett. 45, 313-318 (1984)
DOI: 10.1051/jphyslet:01984004507031300

Molecular orientation and anchoring energy at the nematic-isotropic interface of 7CB

S. Faetti et V. Palleschi

Dipartimento di Fisica, Piazza Torricelli, 2, 56100 Pisa, Italy

Abstract
The properties of the nematic-isotropic interface of the nematic liquid crystal 7CB are studied by optical reflectometry. It is found that at the interface the director is tilted with respect to the vertical axis. Measurements are reported of the tilt angle θt, of the thickness of the interface, and of the anchoring energy.

Résumé
Nous étudions par réflectométrie optique les propriétés de l'interface nématique-isotrope du cristal liquide 7CB. Nous mesurons l'épaisseur de l'interface, l'angle polaire du directeur à l'interface et son énergie d'ancrage.

PACS
6130E - Experimental determinations of smectic, nematic, cholesteric, and lyotropic structures.
6810C - Fluid surface energy surface tension, interface tension, angle of contact, etc..

Key words
interface structure -- molecular orientation -- nematic liquid crystals -- organic compounds -- reflectivity -- surface energy -- interface thickness -- molecular orientation -- 4 cyano 4' n heptylbiphenyl -- anchoring energy -- nematic isotropic interface -- 7CB -- nematic liquid crystal -- optical reflectometry -- director -- tilt angle