Plasma treatment for enhanced functionalization of graphene nanosheets by octadecylamine

We report here a method for enhancing the non-oxygen functionalization of graphene nanosheets. This improvement is taken place by increasing the oxygen functional groups as the active reaction sites on graphene oxide by cold plasma treatment followed by substitution reaction by octadecylamine (ODA). The FTIR, XPS, XRD, RAMAN, and TGA analyses verified that the modification could increase the amount of functional groups by 61%. The plasma-treated functionalized graphene nanosheets were incorporated in polydimethylsiloxane (PDMS) membranes to remove toluene from water in pervaporation and showed an enhanced enrichment factor and pervaporation separation index of 123% and 68%, respectively, compared to those for the membrane incorporated with normally-functionalized reduced graphene nanosheets. The performance enhancement is attributed to the higher degree of functionalization of plasma-treated nanosheets, which causes a more uniform distribution of the nanosheets in the membrane acting as a barrier against water permeation while facilitating the permeation of toluene molecules through the membrane. Hence, this method could be used to increase the degree of functionality of graphenic materials and increase the applicability of these nanoparticles.