Surface modification of the freestanding polyaniline (PANI) base film and coating on low-density polyethylene film was carried opt by graft copolymerization with vinyl benzyl chloride (VBzCl) using UV-induced and heat-induced methods. These samples were characterized by X-ray photoelectron spectroscopy, UV-visible absorption spectroscopy, atomic force microscopy, and conductivity measurements. The reaction of PANI with VBzCl results in the alkylation of the imine nitrogen. The chloride ions (Cl-) formed during the alkylation 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 the VBzCl via the vinyl groups results in the formation of a hydrophobic layer on the PANI surface. The hydrophobic polymer layer acts as the barrier for preventing the undoping of the graft copolymerized samples, and these grafted samples can maintain their conductive state even when exposed to aqueous solutions with pH as high as 12.