Comparative study of n-dodecyl tetraethylene monoether lyotropic liquid crystals incorporated with graphene and graphene oxide

Abstract

Two kinds of carbon materials, i.e., graphene and graphene oxide (GO), were successfully incorporated into a lyotropic liquid crystal (LLC) matrix formed by n-dodecyl tetraethylene monoether (C₁₂E₄). The properties of graphene–C₁₂E₄ and GO–C₁₂E₄ LLC composites were characterized by UV-vis absorption, transmission electron microscopy (TEM) observations, polarized optical microscopy (POM) observations, small-angle X-ray scattering (SAXS) and rheological measurements. SAXS results indicate that both graphene and GO are well-dispersed in the C₁₂E₄ LLC matrix and some interactions occur between the C₁₂E₄ LLC matrix and graphene (or GO) sheets. Moreover, it is demonstrated that graphene interacts with the hydrophobic part of C₁₂E₄ LLC while GO mainly interacts with the hydrophilic part of C₁₂E₄ LLC because of the different properties of graphene and GO. Integration of graphene and GO into C₁₂E₄–PEG systems by a spontaneous phase separation method reveals the different interaction mechanisms of graphene and GO with C₁₂E₄ LLC. It can be concluded that the mechanical and electrical properties of the C₁₂E₄ LLC have been largely improved by the incorporation of graphene and GO, which opens the door for wide applications in nanotechnology, electrochemical and biochemical areas.