J. Phys. II France
Volume 4, Numéro 3, March 1994
Page(s) 407 - 412
DOI: 10.1051/jp2:1994106
J. Phys. II France 4 (1994) 407-412

Columnar and smectic ordering in a TGB $_{\rm A}$ phase

A. C. Ribeiro1, 2, A. Dreyer1, L. Oswald1, J. F. Nicoud1, A. Soldera1, D. Guillon1 and Y. Galerne1

1  Institut de Physique et Chimie des Matériaux de Strasbourg, Groupe des Matériaux Organiques, ICS, 6 rue Boussingault, 67083 Strasbourg Cedex, France
2  Centro de Física da Matéria Condensada, Av. Gamma Pinto, 1699 Lisboa Codex, Portugal

(Received 14 October 1993, revised 21 January 1994, accepted 27 January 1994)

Optical textures characteristic of cholesteric and columnar structures were simultaneously detected for the first time in the same mesophase of a liquid crystal. However, X-ray diffraction measurements show that the mesophase under consideration is smectic A in nature. We show here that the compound presents, indeed, a twist grain boundary (TGB) phase within a large temperature range, and we propose an explanation of the supramolecular organization in this phase.

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