Experimental studies on the self-organization of colloidal inclusions in liquid crystal membranes
1 Université Bordeaux 1, CNRS, Centre de Recherche Paul Pascal, France
Different kinds of colloidal particles dispersed in anisotropic liquids (i.e. liquid crystalline phases) have recently attracted increasing attention for their unique collective behavior. These particles can be embedded either into the bulk of a nematic liquid crystalline phase [1; 2] (3D system) or in a smectic free standing film  (2D system). In both cases, the particles alter the director field alignment in their vicinity. The resulting elastic deformations then drive elastic interactions between the particles which cluster into a great variety of aggregates.
In the case of 2D system, the colloidal particles consist of cholesteric, nematic inclusions or even hard spheres embedded in a tilted smectic free standing film. The elastic distortions induced around the inclusions coupled with the high in-plane anisotropy result in the creation of topological defects and thus elastic interactions.
In this work, we focus on the different possibilities to modify the inclusion interaction by changing the characteristics of the inclusions and of the liquid crystal medium. Transformation of the interaction can be achieved by changing the chirality (polarization value) of the liquid crystal [4,5]; external conditions e.g. temperature ; size and shape of the particles [6,7]. The positions of topological defects on the inclusion boundary and anchoring conditions can be tuned up, by changing the configuration of the liquid crystal near the inclusions, and by this way to a change of the interparticle interaction. The modification of the interparticle interaction leads to the rearrangement of superstructures formed by the inclusions (linear chains, ordered clusters, two-dimensional lattice structures).
The reported phenomena on the change of inclusion interaction open the way to a better control of the structures formed by inclusions.
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