Supramolecular Functionalization of Single-Walled Carbon Nanotubes with Conjugated Polyelectrolytes and Their Patterning on Surfaces

The interaction between single-walled carbon nanotubes and two anionic conjugated polyelectrolytes, poly[2,5-bis(3-sulfonatopropoxy)-1,4-phenylene-alt-1,4-phenylene) sodium salt and poly[2,5-bis(3-sulfonatopropoxy)-1,4-ethynylphenylene-alt-1,4-ethynylphenylene] sodium salt, was investigated. It was found that the supramolecular polymer−nanotube assembly occurred efficiently and produced stable complexes that could be purified from excess free polymer in solution. These complexes were characterized using absorption spectroscopy, fluorescence spectroscopy, Raman spectroscopy, and electron microscopy. It was further found that patterning of these polymer−nanotube complexes could be accomplished by utilizing electrostatic attraction with a prepatterned, cationically charged surface. Patterned features were found to be electrically conducting with a measured sheet resistance value of 0.68 ± 0.01 MΩ for features having a thickness on the order of several nanometers.