Freedericksz-like positional transition of a micro-droplet suspended in a nematic cell

Abstract

In this paper, a Freedericksz-like positional transition is found for a spherical micro-droplet suspended in a nematic liquid crystal cell in the presence of an external electric field. Based on the numerical calculation of elastic energy using Green function method, the equilibrium position of micro-droplet is decided through a competition between the buoyant force and the effective force built by the elastic energy gradient existing inside the nematic liquid crystal(NLC) cell. It is shown that the elastic energy dominates the kinetics of micro-droplet until the external field applied reaches a critical value large enough to flatten the elastic energy contour in the central region, which enables the asymmetric buoyant force to drive the liquid droplet abruptly from the cell midplane to a new equilibrium position. It is also found that such a threshold value of external field, which triggers positional transition, depends on thickness $L$ and Frank elastic constant $K$, in a Freedericksz-like manner, but multiplied by a factor of $3\sqrt{\pi }$. An explicit formula proposed for the critical electric field agrees extremely well with the numerical calculation.

References in corpus (8)

• Topological Defects and Interactions in Nematic Emulsions
• Liquid Crystal Colloids
• Friction Drag on a Particle Moving in a Nematic Liquid Crystal
• Hexadecapolar colloids
• Theory of Elastic Interaction of the Colloidal Particles in the Nematic Liquid Crystal Near One Wall and in the Nematic Cell
• Forces between elongated particles in a nematic colloid
• Elastic interaction between colloidal particles in confined nematic liquid crystals
• Theory of elastic interaction between colloidal particles in the nematic cell in the presence of the external electric or magnetic field

Cited by in corpus (1)

• Formation of a fast "lane" for positional transition in a microparticle-suspended nematic liquid crystal cell