Masoomeh Hashemi: Nonspherical Colloidal Particles in Nematic Liquid Crystals: Role of geometrical parameters

Datum objave: 16. 12. 2014
Seminar fizike mehkih snovi
Ponedeljek, 22. december 2014, ob 10:15 v F3, FMF, Jadranska 19, Ljubljana.

Nonspherical Colloidal Particles in Nematic Liquid Crystals: Role of geometrical parameters

Masoomeh Hashemi, Department of physics, Sharif University of Technology, Tehran, Iran

Since the recognition of a novel class of long range intercolloidal interactions mediated by the elasticity of the nematic liquid crystal host, extensive research has been devoted to the role of particle geometry in uniform nematic media. Defect structures specifically depend on the geometry of the particles. Therefore, by carefully choosing the geometrical shapes of the particles one can be able to design defect structures with pre-determined architecture in a liquid crystal colloidal system. Finite element methods are powerful tools in dealing with colloidal surfaces in liquid crystals. By employing a finite element method for numerical minimization of the Landau-de Gennes free energy we study the equilibrium orientation and defect structures of a circular cylindrical particle with flat ends under homeotropic anchoring condition in a uniform nematic medium. Different aspect ratios of this colloidal geometry from thin discotic to long rod-like shapes and several colloidal length scales ranging from mesoscale to nanoscale are investigated. We show that the equilibrium state of this colloidal geometry is sensitive to the two geometrical parameters: aspect ratio and length scale of the particle.