N-alkylation of polyaniline with simultaneous surface graft copolymerization for inducing and maintaining a conductive state

Surface modification of the freestanding polyaniline (PANI) base film and c oating on low-density polyethylene film was carried opt by graft copolymeri zation with vinyl benzyl chloride (VBzCl) using UV-induced and heat-induced methods. These samples were characterized by X-ray photoelectron spectrosc opy, UV-visible absorption spectroscopy, atomic force microscopy, and condu ctivity measurements. The reaction of PANI with VBzCl results in the alkyla tion of the imine nitrogen. The chloride ions (Cl-) formed during the alkyl ation then serve as the counterions to the N+ components of PANI resulting in a doped and conductive state. At the same time, the polymerization of th e VBzCl via the vinyl groups results in the formation of a hydrophobic laye r on the PANI surface. The hydrophobic polymer layer acts as the barrier fo r preventing the undoping of the graft copolymerized samples, and these gra fted samples can maintain their conductive state even when exposed to aqueo us solutions with pH as high as 12.