Surface graft copolymerization of poly(tetrafluoroethylene) films with N-containing vinyl monomers for the electroless plating of copper

Argon plasma-pretreated poly(tetrafludroethylene) (PTFE) films were subject ed to UV-induced surface graft copolymerization, under atmospheric conditio ns, with several N-containing vinyl monomers, including 4-vinylpyridine (4V P), 2-vinylpyidine (2VP), 1-vinylimidazole (VIDz), 1-vinylpyridinone (VPD), and acrylamide (AAm). Electroless plating of copper could be carried out e ffectively on the 4VP or 2VP graft-copolymerized PTFE surface after PdCl2 a ctivation and in the absence of SnCl2 sensitization. The surface compositio ns of the modified PTFE films were studied by X-ray photoelectron spectrosc opy (XPS). The catalytic processes for the electroless plating of copper in the presence and absence of sensitization by SnCl2 were compared. The adhe sion strength of the electrolessly deposited copper on the graft-modified P TFE surface was affected by the type of the monomers used for graft copolym erization, the graft concentration, and the activation time of the PTFE sur face in PdCl2 solution. The T-peel adhesion strength between the electroles sly deposited copper and the graft-modified PTFE film was further improved in the absence of the SnCl2 sensitization step and could reach as high as 7 N/cm. However, the electroless deposition of copper could not be carried o ut on the pristine or Ar plasma-treated PTFE surface in the absence of SnCl 2 sensitization.