Springer LINK: The European Physical Journal B - Abstract Volume 3 Issue 1 (1998) pp 73-82

The European Physical Journal B

ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)

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Abstract Volume 3 Issue 1 (1998) pp 73-82

Polymorphism and chevron layer structure of an antiferroelectric liquid crystal studied by X-ray diffraction

P. Cluzeau (1) (a), P. Barois (2), H.T. Nguyen (2), C. Destrade (2) (b)

(1) Laboratoire de Dynamique et Structure des Matériaux Moléculaires, Université de Lille 1, 59655 Villeneuve d'Ascq Cedex, France
(2) Centre de Recherche Paul Pascal, avenue A. Schweitzer, 33600 Pessac, France

Received: 13 November 1996 / Received in final form: 19 January 1997 / Accepted: 30 January 1998

Abstract: We report X-ray diffraction experiments performed on an antiferroelectric compound exhibiting a very rich polymorphism ($ {\rm S}_{\rm I^*A} {-} {\rm S}_{\rm C^*A} {-}{\rm S}_{\rm C^*FI1}{-} {\rm S}_{\rm C^*FI2}{-} {\rm S_{C^*}}{-} {\rm S}_{{\rm C}^*\alpha} {-} {\rm S}_{\rm A}$). The structural study of the unknown phases only allows us to exclude some phenomenological models. The use of oriented planar samples prepared between solid glass plates generate by cooling from the ${\rm S}_{\rm A}$ phase a chevron structure of tilted layers already well characterized for the ${\rm S_{C^*}}$ phase. The extensive analysis of the evolution of the chevron structure through the numerous smectic-smectic phase transitions provides some original information in three distinct areas: fundamental data on the important physical parameters in the chevron structure formation, detection of the smectic-smectic phases transition by small change of the chevron structure, and information on the local molecular order induced by the alignment layer (interaction with a rubbed polymer).

PACS. 78.70.Ck X-ray scattering - 61.30.Jf Defects in liquid crystals - 64.70.Md Transitions in liquid crystals

(a) email: cluzeau@lip5rx.univ-lille1.fr
(b) Nous tenons à exprimer ici tout ce que nous devons à Christian Destrade récemment décédé ; il avait su nous communiquer son enthousiasme de longue date pour les propriétés fascinantes des nouvelles phases. C'est donc très humblement que nous lui dédions ce travail.

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