Aryl Diazonium Salts for Carbon Fiber Surface-Initiated Atom Transfer Radical Polymerization

Abstract

, +N2-C6H4-CH(CH3)-Br diazonium salt was electrochemically reduced in order to graft phenylethyl bromide groups to carbon fibers. The pretreated fibers (CF-Br) served as macroinitiators of atom transfer radical polymerization (ATRP) of vinylic monomers. This procedure combining a diazonium salt and ATRP permitted the polymerization of butyl, glycidyl and hydroxyethyl methacrylates at the surface of carbon fibers (CF) resulting in CF-PBMA, CF-PGMA, and CF-PHEMA hybrids, respectively. The surface chemistry and wettability of these hybrids were interrogated by XPS and water contact angles. The change in the wettability of carbon fibers reflects the chemical nature of the tethered polymer chains as the wettability decreases in the order CF-PHEMA > CF-PGMA > CF-PBMA > CF. Furthermore, CF-PHEMA was found to resist non-specific adsorption bovine serum albumin (BSA) compared with the more hydrophobic CF-PBMA system. This work shows that the use of diazonium salt is a facile, new surface chemistry option for grafting initiator of ATRP to carbon fiber. This strategy ensures a good carbon fiber-polymer adhesion through covalent bonds.