J. Phys. II France
Volume 4, Number 4, April 1994
Page(s) 627 - 643
DOI: 10.1051/jp2:1994152
J. Phys. II France 4 (1994) 627-643

Novel sequence with incommensurate SA phases in a new dimesogenic liquid crystal

F. Hardouin1, M. F. Achard1, Jung-Il Jin2, Jin-Wook Shin2 and Yong-Kuk Yun2

1  Centre de Recherche Paul Pascal, Université Bordeaux I, Av. A. Schweitzer, 33600 Pessac, France
2  Department of Chemistry, College of Sciences, Korea University, Seoul 136-701, Korea

(Received 16 November 1993, accepted in final form 10 January 1994)

We present differential scanning calorimetry, optical and X-ray diffraction measurements for a new dimesogenic liquid crystal compound (KI5). The rich polymorphism of this compound includes new smectic phases and rare phase transitions. In particular the first observation in a pure compound of two incommensurate SA phases as well as cholesteric and helical smectic phases (TGB and SC * phases) are reported. We discuss this observation in terms of the dual peculiar structural character of the molecule : a polyphilic and dimesogenic system including the concept of the central flexible spacer.

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