Orientation Change of Graphene Oxide Liquid Crystal Suspension with Various Shear Rates

Abstract

Graphene oxide (GO), often referred to as a two-dimensional colloid, can be easily dispersed in water and form nematic liquid crystal (LC) phase. Based on the good dispersibility and ability to form LC phase, GO can be fabricated to fibers or films through solution processing. The performance of GO LC fibers can be dependent on their colloidal stability and alignment, which can be deformed as it experiences strong shear stress during fiber processing. However, the detailed characterization of microstructure and properties of GO has not been attempted yet especially under shearing condition. Here, we investigate the microstructure of GO LC with varying shear rate and correlate it with rheological properties employing in-situ Rheo-small angle X-ray scattering and in-situ polarized optical microscopy. We demonstrate that the LC structure can be continuously varied with shear rate and the shear rate dependency can be controlled with the concentration and size of GO.