Non-covalent functionalization of graphene with a hydrophilic self-limiting monolayer for macro-molecule immobilization

Abstract

Two different pyrene-substituted ions were used to render the surface of graphene hydrophilic. Self-limiting monolayers of ammonium and sulfonate substituted pyrenes were used to give, respectively, an overall positive and negative charge to the surface. Both pyrenes gave a stable hydrophilic surface and were used to selectively immobilise negatively or positively charged macro-molecules. This simple and versatile non-covalent approach can be used on graphene on a variety of substrates (e.g. copper, SiO2), suspended graphene, and also for graphite.