Dispersion behavior of single-walled carbon nanotubes by grafting of amphiphilic block copolymer

The grafting of polystyrene-polyacrylamide (PS–PAM) block copolymer to single-walled carbon nanotubes (SWNTs) was achieved by in situ living free radical polymerization. The resulting dispersions were stable and had homogeneous dark ink-like appearance, consisting mainly of long isolated nanotubes and thin bundles, which were confirmed by scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV–vis spectrometry. Long-term stabilization was achieved by covalently bonding of copolymer. This method is beneficial because the amphiphilic property of the block copolymer can help to stabilize SWNTs in both polar and non-polar solvents at the same time.