Surface graft copolymerization induced adhesion of polyaniline film to polytetrafluoroethylene film and copper foil.

Adhesion of emeraldine base (EB) films of polyaniline (PANI) to plasma-pret reated polytetrafluoroethylene (PTFE) films and to copper foils were achiev ed via thermally induced surface graft copolymerization with concurrent lam ination. The process was carried out under atmospheric conditions in the pr esence of pure and aqueous solutions of I-vinyl imidazole (VIDz) or acrylic acid (AAc) and in the absence of an added polymerization initiator. The ch emical composition and microstructure of the graft copolymerized surfaces f rom the self-delaminated junction in water and from the mechanically delami nated interfaces were investigated by X-ray photoelectron spectroscopy (XPS ). The effects of monomer concentration and thermal grafting/lamination tem perature on the observed lamination strength were studied for both the EB/P TFE and EB/Cu interfaces. The lap shear adhesion strength of the EB/PTFE ju nction also depended on the plasma pretreatment time of the PTFE surface. M aximum lap shear adhesion strength approaching 200 N/cm(2) was obtained for the EB/PTFE interface laminated at 140 degrees C for 1 h in the presence o f pure AAc monomer and with 40 s of Ar plasma pretreatment time for the PTF E surface. A maximum lap shear adhesion strength of about 640 N/cm(2) could be readily achieved for the EB/Cu interface for grafting/lamination carrie d out in the presence of 25 vol% aqueous VIDz solution at 130 degrees C. (C ) 1999 Elsevier Science Ltd. All rights reserved.