Conventional and non-conventional spreading of a mesogenic material
INFM unità di ricerca c/o Dipartimento di Fisica, Università della
Arcavacata di Rende, 87036 Cosenza, Italy
2 Physique de la Matière Condensée, Collège de France, 11 place Marcelin Berthelot 75006 Paris, France
Accepted: 25 March 1996
Optical microscopic and ellipsometric studies of the spreading of a mesogenic compound on a rough substrate are reported on. The smectic wets the surface and a precursor film grows whose radius R scales like the square root of time t : . The diffusion coefficient decreases with temperature and vanishes several degrees below the melting temperature, i.e. the solid phase also "spreads out" through a precursor film. The effect is analysed in terms of surface-induced premelting. This is the first report on such an effect in mesogenic materials.
PACS: 61.30.-v – Liquid crystals / 64.70.Md – Transitions in liquid crystals / 68.45.-v – Solid-fluid interfaces
© EDP Sciences, 1996