Graphene oxide and reduced graphene oxide in the anisotropic media of nematic liquid crystals 4’-pentyl-4-cyano-biphenyl

Abstract

ABSTRACTGraphene oxide is hydrophilic due to its oxygen functionality, making it easy to disperse in liquid crystalline media. The nanocomposites of graphene oxide and reduced graphene oxide have been prepared in a nematic liquid crystal. Results reveal rising transition temperatures, enthalpies, and order parameters for graphene oxide dispersed nanocomposites. UV-Vis spectroscopy results show an increase of the optical band gap for graphene oxide whereas decrease for reduced graphene oxide dispersed system. Impedance spectroscopy is used for the determination of various parameters such as permittivity, dielectric anisotropy, conductivity, relaxation frequency and activation energy. Results show that the dielectric anisotropy is increased for graphene oxide dispersed nanocomposite, however, reduced graphene oxide dispersed system demonstrates the opposite property. Relaxation frequency has increased for graphene oxide dispersed system while unchanged for reduced graphene oxide dispersed system. Conductivity of reduced graphene oxide dispersed nanocomposite has increased by three orders of magnitude but for graphene oxide dispersed system, it has decreased as compared to that of the pure sample. We observed decrease in threshold voltage, elastic constant, and rotational viscosity for both GO/rGO dispersed systems. The outcome for the graphene oxide dispersed nanocomposite looks to be more effective due to the system’s enhanced molecular polarisability.