Synthesis of a carboxyl-containing conducting oligomer and non-covalent sidewall functionalization of single-walled carbon nanotubes

A carboxyl-containing conducting oligomer, poly( pyrenebutyric acid) (PPBA), has been synthesized for non-covalent sidewall functionalization of single-walled carbon nanotubes (SWNTs) by direct oxidation of alpha-pyrenebutyric acid (PBA) in boron trifluoride diethyl etherate (BFEE) containing SWNTs. The initial feeding weight ratio of the monomer and SWNTs can strongly influence the thickness of the oligomer coating on SWNTs and also the diameter of the fibril nanocomposites. The pyrene moieties of PPBA interacted with the sidewalls of SWNTs because of their large aromatic rings, which meant that the composite could be stably dispersed in many common organic solvents and aqueous alkaline solutions. The structure and optical properties of PPBA and SWNT/PPBA composites have also been studied.