Surface Graft Copolymerization of Poly(tetrafluoroethylene) Films with N-Containing Vinyl Monomers for the Electroless Plating of Copper

Argon plasma-pretreated poly(tetrafluoroethylene) (PTFE) films were subjected to UV-induced surface graft copolymerization, under atmospheric conditions, with several N-containing vinyl monomers, including 4-vinylpyridine (4VP), 2-vinylpyridine (2VP), 1-vinylimidazole (VIDz), 1-vinylpyridinone (VPD), and acrylamide (AAm). Electroless plating of copper could be carried out effectively on the 4VP or 2VP graft-copolymerized PTFE surface after PdCl 2 activation and in the absence of SnCl 2 sensitization. The surface compositions of the modified PTFE films were studied by X-ray photoelectron spectroscopy (XPS). The catalytic processes for the electroless plating of copper in the presence and absence of sensitization by SnCl 2 were compared. The adhesion strength of the electrolessly deposited copper on the graft-modified PTFE surface was affected by the type of the monomers used for graft copolymerization, the graft concentration, and the activation time of the PTFE surface in PdCl 2 solution. The T-peel adhesion strength between the electrolessly deposited copper and the graft-modified PTFE film was further improved in the absence of the SnCl 2 sensitization step and could reach as high as 7 N/cm. However, the electroless deposition of copper could not be carried out on the pristine or Ar plasma-treated PTFE surface in the absence of SnCl 2 sensitization.