Microscopic characterisation of self-assembled colloidal particles in electrohydrodynamic convection of a low-birefringence nematic liquid crystal

Abstract

Electrokinetics of small particles immersed in anisotropic fluids is attracting attention in recent years. Here we focus on microscopic appearance of single as well as self-assembled particles moving in the electrohydrodynamic convection (EHC) of a nematic liquid crystal with low-birefringence. Characterization of the birefringent properties is made by polarized light microscopy under different illumination conditions. Because of the small optical anisotropy, the director distortion around the particles clearly exhibits distinctive colors on both sides depending on the height in the cell. The observation can be explained as the change in the net phase retardation of the light. It is also found that a caterpillar-like motion is possible by tuning temperature, although the horizontal size of the EHC rolls is relatively narrow.

Large-scale self-organization of reconfigurable topological defect networks in nematic liquid crystals

“…8b). This is reasonable because EHC occurs for planar and homeotropic anchoring5758. Even in the EHC region, the grid can be maintained with good stability.…”

Nonlinear Electrophoresis of Colloids Controlled by Anisotropic Conductivity and Permittivity of Liquid-Crystalline Electrolyte

“…We direct the structural dipole is antiparallel to the direction of dipole, 0 v < [9]. Theoretically, the amplitude of electrophoretic velocity is predicted to be [9] ( ) [8,9,11,[13][14][15] and in the guiding effect of the director field [8,11,[16][17][18][19], there are no experimental data on how v depends on ε% and σ% , the two crucial properties of the nematic electrolyte. As predicted by Eq.…”

Light-Induced Structures and Microparticle Transportation in a Free-Surface Frustrated Chiral Nematic Film

“…In the field of microscopic object manipulation, a lot of attention has been paid to the electrically induced transport phenomena in nematic liquid crystals, based on electrophoresis and electro-osmosis, electrohydrodynamic convection or backflow powered by director reorientations [4][5][6][7]. The presence of either artificially placed or self-generated wall defects allows the microparticles to exhibit a rich set of motions and provide control of their velocity [8,9].…”