Silane functionalization of graphene nanoplatelets

Abstract

The lack of a facile route for the functionalization of highly sp² hybridized, low oxygen content (<10 atm%, C:O > 9:1) graphene nanoplatelets (GNP) has greatly hindered full exploitation of these materials. Moreover, the highly conductive and paramagnetic properties of GNP can exclude the use of solid-state nuclear magnetic resonance spectroscopy (SS-NMR) and electron paramagnetic resonance spectroscopy (EPR), even at liquid helium temperatures, to prove binding of silane to the GNP surface is successful. Here, three model silanes, 3-Mercaptopropyltrimethoxysilane, 3-Methacryloxypropyltrimethoxysilane and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane were successfully bound to the surface of GNP, each following either a condensation silanization reaction or a pathway dependent on the R-group of each silane. Several techniques were employed, but critically a combination of X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis-mass spectrometry (TGA-MS) in argon and air confirmed successful binding of the silane to the GNP. The approach adopted makes available the pendant R-group on the silane for interaction or reaction with polymers and a route to significantly modifying the properties of polymers and surfaces.