Effects of poly(ethylene glycol) on the wetting behavior and director configuration of lyotropic chromonic liquid crystals confined in cylinders

Abstract

© The Royal Society of Chemistry 2019.We investigate the effects of poly(ethylene glycol) (PEG) doping on nematic lyotropic chromonic liquid crystals (LCLCs) confined in a cylindrical cavity. First, PEG added to Sunset Yellow (SSY) renders confining glass surfaces nemato-phobic by adsorption. We also confirm that the grafting of PEG to bare glass surfaces changes them from nemato-philic to nemato-phobic. This change in the wetting behavior affects how nematic director configurations form and relax. Additionally, we observe that PEG-doped nematic SSY retains the double-twist director configuration as in the PEG-free case. However, the PEG-doped nematic SSY is accompanied by unprecedented domain-wall-like defects and heterogeneity in the director configuration. We propose multiple hypotheses on how PEG changes the director configuration, including the formation of meta-stable director configurations