Smectic A-Smectic B interface : faceting and surface free energy measurement

P. Oswald , F. Melo , C. Germain

We have observed the equilibrium shape of a Smectic B monodomain in contact with a Smectic A phase and how a grain boundary deforms the Smectic B-Smectic A interface in the presence of a temperature gradient. The chosen material is the 40.8 (butyloxybenzilidene octylaniline). By using the Wulff construction and the T.L.K. model, we calculate both the surface free energy of a facet parallel to the layers and the free energy of a ledge. The existence of faces of forbidden orientations is also shown. In accord with the theoretical predictions of Herring, we observe that such a face is always unstable with respect to the formation of a hill-and-valley structure.

Mots clés: free energy; liquid crystal phase transformations; smectic liquid crystals; surface energy

Domaines: Articles anciens

P. Oswald, F. Melo, C. Germain. Smectic A-Smectic B interface : faceting and surface free energy measurement. Journal de Physique, 1989, 50 (24), pp.3527-3534. ⟨10.1051/jphys:0198900500240352700⟩. ⟨jpa-00212343⟩