Electric field responses of liquid crystalline colloidal dispersions of clay mineral nanosheets

Abstract

Electric field responses of the lyotropic liquid crystals of layered clay minerals nanosheets, fluorohectorite (FHT) and fluorotetrasilicic mica (FTSM), were investigated as the functions of nanosheeet concentration, nanosheet size, and frequency. By applying alternating electric field (100 Hz, 30 V/mm) to the FHT system of smaller nanosheet size, birefringent domains began to appear and disappear as observed by polarized microscopy with crossed polarizers, indicating electrophoretic convection of the liquid crystalline nanosheets. As the frequency increased to larger than 1 KHz, the convection immediately stopped and a more birefringent domain with a larger size emerged. The increases in concentration and the size of the nanosheets as well as the frequency were responsible for larger domain size and stronger birefirngence. The FTSM system showed vague textures compared to FHT systems.