Colloidal inclusions in smectic films with spontaneous bend

Abstract

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.

Colloidal particles in liquid crystal films and at interfaces

“…The case of chiral SmC* can be modeled by introducing an additional elastic term, ∝ ∇ × c, to the two-dimensional elastic free energy density of SmC [ 97,98]. This term allows for a spontaneous bend deformation of the c-director and favors the dipolar defect configuration with two −1/2 surface defects placed at one side of the inclusion.…”

Colloidal gold nanosphere dispersions in smectic liquid crystals and thin nanoparticle-decorated smectic films

“…Dispersions of colloidal particles in anisotropic liquid crystalline media are interesting from both fundamental physics and technological applications standpoints. Studies of colloidal microparticles in nematic [1][2][3][4][5] and smectic [6][7][8][9][10][11] liquid crystals ͑LCs͒ reveal strongly anisotropic long-range interactions that can be of both attractive and repulsive nature. 2 The interactions depend on topological defects and director structures occurring around the particles and are mediated by orientational elasticity of the surrounding LC medium.…”

“…Colloidal inclusions in smectics distort the surrounding ground-state structure of uniform LC director and equidistant lamellae. [6][7][8][9][10][11] These elastic distortions of the layered structure can also result in elasticity-mediated interparticle interactions. However, it is not known if stable dispersions of nanoparticles in such systems are possible.…”

Impact and Embedding of Picoliter Droplets into Freely Suspended Smectic Films

“…The relevant parameters are defined in Figure 6, on the left hand side is the sketch of the droplet and definition of the geometrical quantities, on the right we sketch schematically the enlarged part of the interface between droplet and film. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 This equation is equivalent to 46,51 …”