Oligomeric ethylene-glycol brush functionalized graphene oxide with exceptional interfacial properties for versatile applications

Abstract

Graphene oxide (GO) has continued to prompt fantastic discoveries and applications; however, the highly extended two-dimensional π-conjugation of pristine graphene sheets leads to the aggregation of GO sheets in strong brine, which impairs the applications of GO. In this work GO with covalently-bound oligomeric ethylene–glycol brushes (termed as GOC) was prepared using graphite oxide as a raw material. The synthesized GOC was investigated by a holistic combination of experimental characterizations and molecular dynamic simulations. Our results showed that GOC behaves like a highly anisotropic colloid that well dispersed in various organic solvents, and retained high dispersion stability in strong brine even after storage at high temperature (e.g, 90 ℃). The GOC can sharply decrease surface tension after reaching a very low threshold concentration of 0.04 mg/mL; on account of that, it successfully generated water-in-oil Pickering emulsions with an internal water content of as high as 90 vol%. The GOC also functions as a liquid crystal at the oil–water interface without the need of external assistances/stimuli. We envisage that the prepared multifunctional GOC materials will stimulate a broad range of its applications when exceptional interfacial properties are required such as in the field of food, cosmetics, and petroleum industries.