Inclusions in Smectic C Films as Modeled by Disclinations

Abstract

A simplified model of an inclusion represented by (+1)-wedge disclination and two accompanying (−1/2)-wedge disclinations on the surface of inclusion in smectic C free standing films is used to describe the elastic interaction of inclusions. The orientation of the axis connecting positions of all three disclinations relatively to the director orientation at far distances due to elastic anisotropy is investigated. The configuration with the lowest director perturbations and the lowest anisotropy elastic energy is such that the axis connecting disclinations is parallel to the distant director orientation. The interaction between inclusions at far distances is quadrupolar. The chaining of inclusions is approximately described considering their repulsion due to molecular anchoring at inclusion surfaces.PACS : 61.30.Jf

Colloidal particles in liquid crystal films and at interfaces

“…Isotropic or nematic inclusions in SmC films impose planar anchoring on the c-director [85][86][87][88]93]. A similar situation is observed for smectic islands [88,91].…”

Interaction of an inclusion and (±1)-wedge disclination in smectic C free standing films

“…The c-director describes the projection of S C molecules onto the smectic layers plane [9,10]. In some special cases the smectic layer deformation caused by an inclusion creation can be neglected as discussed in [7] and director deformations near inclusions can be simply described by models based on disclinations [4][5][6][7][8].…”

“…Thus the inclusion behaves as to have (+1)-wedge disclination at its centre and the configuration of (−1/2)-(+1)-(−1/2) wedge disclinations representing the inclusion leads to the uniform director far from inclusion. In Refs [5,6,8,9] the observed formation of the inclusion chains is explained as a consequence of quadrupolar inclusion interactions.…”

“…In the following, the layer elasticity will be neglected as in [9]. As inclusions in films are nucleated at temperatures near S C -N phase transition, the compressibility modulus approaches zero [10].…”

“…Such deformations do not influence the interaction of inclusion with (±1)-disclination. The inclusion will be then considered as a perturbation in c-director field and it can be described using wedge disclinations [4,[7][8][9].…”