Eur. Phys. J. B 11, 121-126 (1999)
https://doi.org/10.1007/s100510050922

Experimental investigations of a new TGBc mesophase

¹ Centro de Fisica da Matéria Condensada (U.L.), Av. Prof. Gama Pinto 2, 1699 Lisboa Codex, Portugal
² Centre de Recherche Paul Pascal, CNRS, avenue A. Schweitzer, 33600 Pessac, France
³ Institut de Physique et Chimie des Matériaux de Strasbourg, Groupe des Matériaux Organiques, 23 rue du Loess, 67037 Strasbourg Cedex, France

Corresponding author: ^a guillon@michelangelo.u-strasbg.fr

Received: 25 January 1999
Published online: 15 September 1999

Abstract

We report on optical and structural X-ray studies on a smectic C twist grain boundary phase (TGB_C) of a pure liquid crystalline material. It is shown that this TGB_C phase, which exists over a large range of temperature, is definitely different from previously reported and predicted TGB_C phases. The two main experimental features are: (i) the observation in planar geometry of an optical texture exhibiting a square grid pattern, and (ii) the detection of a broad Bragg ring in reciprocal space instead of one (TGB_A) or two (TGB_C) sharp rings. We suggest a few possible tracks that can be explored to understand the complex structure of this new phase.