Immobilization of oligoquinoline chains on single-wall carbon nanotubes and their optical behavior

Polymerization of vinylquinoline monomers onto properly modified single-wall carbon nanotubes (SWNT) using atom transfer radical polymerization (ATRP) conditions resulted in efficient grafting of optically active oligomeric chains onto the nanotubes. Two different carbon nanotube (CNT) modification procedures were used, resulting in amino- or hydroxy-functionalized CNTs, which were finally converted to active ATRP initiators. Polymerization of the vinylquinoline monomer resulted in highly soluble oligoquinoline-modified SWNTs. Characterization of these materials was performed using TGA, FT-IR, UV-vis, UV-vis-NIR, and photoluminescence spectroscopies. Immobilization of the quinoline units onto the nanotubes surface greatly influences their optical behavior as shown explicitly for the case of the protonated analogues. Also, an electron transfer from the excited quinoline units to the SWNT was detected.