Colloidal inclusions in smectic films with spontaneous bend
Institute of Experimental Physics, Nonlinear Phenomena, Universitätsplatz 2, D-39016, Magdeburg, Germany
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Accepted: 24 April 2007
Published online: 18 May 2007
Inclusions in free-standing smectic films are simple model systems for two-dimensional anisotropic dispersions. From theory and experiment, different topologies of elastic distortions of the embedding liquid crystal are known. Quadrupolar and different dipolar defect configurations in the vicinity of the inclusion are possible, and these configurations determine the type of interactions between the inclusions. The quadrupolar configuration is often energetically preferred. We show, however, that dipolar director configurations around inclusions can be energetically favourable over quadrupolar arrangements in chiral smectics, as a consequence of a spontaneous-bend term in the elastic-energy formulation. As the inclusion size influences the selection of the deformation types, the corresponding spontaneous-bend constant can be estimated for the strong anchoring limit if the c -director fields around inclusions of different diameters are taken into account.
PACS: 61.30.Dk Continuum models and theories of liquid crystal structure – / 61.30.Jf Defects in liquid crystals – / 61.30.Hn Surface phenomena: alignment, anchoring, anchoring transitions, surface-induced layering, surface-induced ordering, wetting, prewetting transitions, and wetting transitions –
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2007