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Soft Matter and Biological Physics
Eur. Phys. J. E 10, 231-240 (2003)
DOI: 10.1140/epje/i2002-10109-x

Self-organization of $\chem{N^{*}}$ inclusions in $\chem{SmC^{*}}$ free-standing films

P. Cluzeau1, V. Bonnand1, G. Joly1, V. Dolganov2 and H.T. Nguyen3

1  Laboratoire de Dynamique et Structure des Matériaux Moléculaires, UMR CNRS 8024, Université de Lille I, 59655 Villeneuve d'Ascq, France
2  Institute of Solid State Physics, Russian Academy of Sciences, 142432, Chernogolovska, Moscow district, Russia
3  Centre de Recherche Paul Pascal, CNRS, Avenue A. Schweitzer, 33600 Pessac, France

Philippe.cluzeau@univ-lille1.fr

(Received 1 July 2002 / Published online: 15 April 2003)

Abstract
The behaviour of freely suspended smectic-C* ( $\chem{SmC^{*}}$) films at the bulk $\chem{SmC^{*}}$-cholesteric ( $\chem{N^{*}}$) phase transition has been investigated using polarized-reflected-light microscopy. Our experimental observations show that above the bulk $\chem{SmC^{*}}$- $\chem{N^{*}}$ phase transition the $\chem{N^{*}}$ order appears in different ways according to the film thickness. In thin films, the conventional layer-by-layer thinning occurs. In films of intermediate thickness $\chem{N^{*}}$ inclusions nucleate inside the $\chem{SmC^{*}}$ film. The distortions of the in-plane orientational order of the $\chem{SmC^{*}}$ host phase induce elastic interactions between the inclusions and lead to their self-organization in chain-like structures. Both the dynamic of the chaining and the parameters driving the equilibrium distance between the inclusions in the chain are investigated. In thick films, $\chem{N^{*}}$ fingers grow inside the film. The influence of the experimental conditions on the various processes is analysed.

PACS
64.70.Md - Transitions in liquid crystals.
61.30.Jf - Defects in liquid crystals.
61.30.Gd - Orientational order of liquid crystals; electric and magnetic field effects on order.

© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2003