Enhancement of growth and adhesion of electroactive polymer coatings on polyolefin substrates

The coating of polyaniline (PAN) and polypyrrole (PPY) films on low-density polyethylene (LDPE) substrates was carried out via immersion of the substrate in a reaction mixture of the monomer, an oxidizing agent, and a doping agent or counterion. The effects of the immersion time in the reaction mixture, the doping agent, and the nature of the substrate's surface were investigated. The coatings were characterized using ultraviolet (UV)-visible absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), and conductivity measurements. The substrate's surface plays a major role in determining the growth and adhesion of the electroactive film. LDPE grafted with acrylic acid (AAc) greatly enhances the growth of the electroactive films on the substrate surface. The N,N-dimethylacrylamide (DMAA) graft copolymerized LDPE also affects the growth of the PAN film but not that of the PPY film. Both the AAc and DMAA graft copolymerized substrates promote the adhesion of the electroactive films.