Electroless deposition of copper and nickel on poly(tetrafluoroethylene) films modified by single and double surface graft copolymerization

Surface modification of Ar plasma-pretreated poly(tetrafluoroethylene) (PTF E) films via W-induced graft-copolymerization with glycidyl methacrylate (G MA) and 1-vinylimidazole (VIDz) was carried out to improve the adhesion wit h the electrolessly deposited copper and nickel. The surface compositions a nd microstructure of the graft-copolymerized PTFE films were studied by X-r ay photoelectron spectroscopy (XPS) and atomic force microscope (AFM), resp ectively. Prior to the electroless deposition of the metals, the graft-modi fied PTFE surfaces were sensitized by SnCl2, followed by activation with Pd Cl2. The electroless plating of Cu and Ni on the VIDz graft-copolymerized P TFE (VIDz-g-PTFE) film could also be carried out in the absence of sensitiz ation by SnCl2 (the Sn-free activation process). The adhesion strength of t he electrolessly deposited metal on the PTFE surface was affected by the ty pe of monomers used for graft copolymerization and the surface graft concen tration. The optimum T-peel adhesion strengths of the electrolessly deposit ed Cu on the VIDz and GMA graft-copolymerized PTFE films were about 2.7 and 6.3 N/cm, respectively The T-peel adhesion strengths of the electrolessly deposited Ni on the corresponding PTFE surfaces were slightly lower. The T- peel adhesion strengths of the electrolessly deposited Cu and Ni were furth er enhanced to about 10 N/cm on the PTFE surfaces modified by consecutive g raft copolymerizations (double graft copolymerization) with GMA and VIDz. ( C) 2001 Elsevier Science B.V. All rights reserved.