Functionalization of carbon nanotubes with well-defined functional polymers via thiol-coupling reaction

Thiol-reactive-functionality decorated multiwalled carbon nanotubes (MWNTs) have been obtained. Trithiocarbonate-ended poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA) is prepared by reversible addition-fragmentation chain transfer (RAFT) polymerisation of N-(2-hydroxypropyl)methacrylamide (HPMA) using S-1-dodecyl-S'-(alpha,alpha'-dimethyl-alpha"-acetic acid)trithiocarbonate as chain transfer agent, subsequently, thiol-terminated PHPMA (PHPMA-SH) is obtained by treating trithiocarbonate-ended PHPMA with hexlamine. The PHPMA-S-S-MWNT conjugate is formed by simply stirring the mixture of thiol-reactive-functionality decorated MWNTs with PHPMA-SH in phosphate buffered saline by a thiol-coupling reaction. FT-IR, HRTEM, H-1 NMR, and TGA results show that this thiol-coupling reaction is effective to produce aqueous soluble polymer-MWNT conjugates under mild conditions.