Grafted Polymer Onto Carbon Nanotubes By Reversible Addition Fragmentation Chain-transfer Active Polymerization

Since their discovery in 1991, singlewall carbon naonotubes (SWNT) and multiwalled carbon nanotubes (MWNT) have encouraged the development of new nanotechnologies because of their outstanding electronic, mechanical and thermal properties. However, since carbon nanotubes are large molecules with thousands of carbon atoms in an aromatic delocalized system and strong intertube van der Waals attraction, they are practically insoluble in all solvents and, consequently, their applications are limited.In this aricle, we grafted dithioester compounds onto the surface of carbon nanotubes as chains transfer agent of reversible addition-fragmentation chain transfer (RAFT) polymerization. Then the Polystyrene (PS) , polymethyl methacrylate (PMMA) and pH-sensitive poly(acrylic acid) chains were grown from the surface of carbon nanotubes via RAFT polymerization. We found that after wrapped with polymer chains, the solubility and stabilization of CNTs in common solvents were proved greatly. And synthesized a core-shell nanostructure with a pH-sensitive shell by RAFT polymerization.FTIR, XPS and ~1H-NMR were used to determine chemical structure and the grafted polymer quantities of the resulting products be examined by TGA, TEM images of the samples provide direct evidence for the formation of a core-shell nanostructure.