Surface Modification Of Graphene And Carbon Nanotubes Grafted With Poly (Ionic Liquid)

The graphene and carbon nanotubes (CNT) have drawn considerable attention due to their excellent chemical and physical properties. But their hydrophobicity and agglomeration limit their applications in various aspects. In this paper, graphene oxide (GO) and carbon nanotubes covalently functionalized by poly(ionic liquid) brushes (P[MATMA][BF4]) were prepared by surface-initiated atom transfer radical polymerization (ATRP). And the functionalized graphene and carbon nanotubes with positive charges can dispersed in aqueous stably. Their absorption performance of carbon dioxide (CO2) was measured.The functionalized graphene and carbon nanotubes were characterized and confirmed by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), ζ potential measurement, four-probe electrical measurements et al. Results demonstrated that the poly(ionic liquid) brushes could be covalently grafted from the GO and carbon nanotubes surface. The surface charges of the GO and carbon nanotubes surface transformed from negative to positive. The reduced functionalized GO (RGO-P[MATMA][BF4]) exhibits electrical conductivity three magnitudes higher than that of original GO. Although partially reduced GO platelets were not as conductive as reduced GO without functionalization, they can be homogenously dispersed in water due to the presence of poly(ionic liquids) brushes. The funtionalized carbon nanoubes (CNT-P[MATMA][BF4]) were also not as conductive as unmodified carbon nanotubes but can be homogenously dispersed in water.The CO2absorption experimental results showed that the functionalized GO and RGO had a stronger absorption than unmodified GO and RGO. For functionalized carbon nanotubes (CNT-P[MATMA][BF4]), the CNT-P[MATMA][BF4] showed a stronger absorption than original CNT at atmospheric pressure, but the absorption volume would be reduced as the temperature increased. The absorption ability of the CNT-P[MATMA][BF4] was better than the original CNT when the pressure below10bar, but the original CNT was better than CNT-P[MATMA][BF4] while the pressure above10bar.