Functionalization of Multiwalled Carbon Nanotubes by Atom Transfer Radical Polymerization and Defunctionalization of the Products

Abstract

A core−shell hybrid nanostructure, possessing a hard backbone of multiwalled carbon nanotube (MWNT) and a soft shell of brushlike polystyrene (PS), was successfully prepared by in situ atom transfer radical polymerization (ATRP), using Cu(I)Br/N,N,N‘,N‘‘,N‘‘-pentmethyldiethylenetriamine (PMDETA) as the catalyst, at 100 °C in diphenyl ether solution. The molecular weight of PS was well controlled, as was the thickness of the shell layer. TEM images of the samples provided direct evidence for the formation of a core−shell structure, i.e., the MWNT coated with polymer layer. FTIR, 1H NMR, SEM, and TGA were used to determine the chemical structure, morphology, and the grafted PS quantities of the resulting products. To further establish the covalent linkage between PS and MWNT moieties, the resulting PS-functionalized MWNTs were defunctionalized by hydrolysis or by thermal decomposition. Comparative studies, based on TEM and SEM images between the PS-functionalized and chemically defunctionalized MWNT samples...