| Numéro |
J. Phys. II France
Volume 5, Numéro 7, July 1995
|
|
|---|---|---|
| Page(s) | 927 - 935 | |
| DOI | https://doi.org/10.1051/jp2:1995221 | |
J. Phys. II France 5 (1995) 927-935
From Incommensurability to Commensurability in Smectic Phases for a Series of Dimesogenic Liquid Crystals
F. Hardouin1, M.F. Achard1, Jung-Il Jin2 and Yong-Kuk Yun21 Centre de Recherche Paul Pascal, Université Bordeaux I, avenue A. Schweitzer, 33600 Pessac, France
2 Department of Chemistry, College of Sciences, Korea University, Seoul 136-701, Korea
(Received 9 February 1995, accepted 5 April 1995)
Abstract
Genuine incommensurate smectic A phases were recently discovered, among the rich polymorphism of a new dimesogenic liquid
crystal compound (KI5). In the present paper, we examine the role played by molecular parameters in the existence of such
incommensurate state. In a series of several homologues of KI5, we find that two smectic modulations exist in agreement with
the phenomenological model of "frustrated smectics". The condensation of one or the other of these modulations and their coexistence
appear to be closely related to the length of the flexible spacer linking the two mesogenic moieties. We observe that only
for intermediate spacer length, the elasticity of the system allows the occurrence of incommensurate SA phases.
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