Lamination of conductive polypyrrole films to poly(tetrafluoroethylene) films via interfacial craft copolymerization

A simple technique for the lamination of a conductive polymer film to an in ert dielectric polymer film was demonstrated. The electrochemically synthes ized and p-toluenesulfonic acid-doped polypyrrole (PPY) film was laminated simultaneously to the argon plasma-pretreated PTFE film during the thermall y induced graft copolymerization of the PTFE surface with a functional mono mer. The graft copolymerization was carried out using glycidyl methacrylate (GMA) monomer containing 20% v/v hexamethyldiamine (HMDA) and in the absen ce of any polymerization initiator. Thermally induced graft copolymerizatio n of the GMA monomer on the PPY surface was minimal. The lap shear and T-pe el adhesion strengths of the laminates were found to be dependent on the GM A graft concentration on the PTFE surface, which, in turn, was affected by the plasma pretreatment time of the film. To increase the GMA graft concent ration for the enhancement of adhesion strength, the plasma-pretreated PTFE surfaces were premodified via UV-induced graft copolymerization with GMA p rior to the simultaneous thermal graft copolymerization and lamination proc ess. The modified surfaces and interfaces were characterized by X-ray photo electron spectroscopy (XPS). Through XPS measurements of the delaminated su rfaces, it was found that the PPY/PTFE laminates failed predominantly by co hesive failure inside the PTFE substrate. (C) 2001 John Wiley & Sons, Inc.