Modification of graphene oxide via photo-initiated grafting polymerization

In this paper, we report on an effective surface modification method for the functionalization of graphene oxide (GO) via photo-initiated radical polymerization. Two cases are investigated, i.e., photoinitiators are chemically attached on GO or are just mixed with GO. The monomer used for surface graft is water-soluble 2-(dimethylamino) ethyl methacrylate (DMAEMA). Analysis based on Fourier transform infrared spectra, Raman spectra, X-ray photoelectron spectroscopy, thermogravimetric analysis, and element analysis demonstrates that PDMAEMA chains are successfully grafted onto GO surface in both cases. In addition, we study the effects of UV irradiation energy and the concentration of initiators on the polymerization. Both UV irradiation energy and the concentration of initiators do not have significant effects on the grafting degree; however, the concentrations of the initiators have impact on the length of the polymer chains grafted onto GO in the case of mixed photoinitiators with GO. The chain length of polymer is shorter with the higher photoinitiator concentration.