J. Phys. II France
Volume 7, Number 11, November 1997
Page(s) 1577 - 1596
DOI: 10.1051/jp2:1997204
J. Phys. II France 7 (1997) 1577-1596

SiO Evaporated Films Topography and Nematic Liquid Crystal Orientation

M. Monkade1, Ph. Martinot-Lagarde1, G. Durand1 and C. Granjean2

1  Laboratoire de Physique des Solides URA 2 CNRS, Bâtiment 510, Université Paris-Sud, 91405 Orsay Cedex, France
2  Laboratoire de Génétique Moléculaire, Bâtiment 32, CNRS, 91198 Gif-sur-Yvette Cedex, France

(Received 24 October 1996, revised 1 July 1997, accepted 29 July 1997)

We present transmission electron microscopy micrographs of SiO films obliquely evaporated on indium-tin oxide coated glass surfaces. To study the growth mechanism of these SiO films, we present film cross sections in the evaporation plane. Varying the evaporation angle, we observe a column to needle transition, with increasing surface roughness. This transition corresponds to the planar to oblique nematic liquid crystal orientation transition, through the bistable one. The SiO surface roughness is estimated to induce a nematic surface order decrease (surface melting). The azimuthal nematic orientation on these plates corresponds to the direction of minimum surface melting. This confirms the predictions of the Barbero-Durand model.

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