Microporous metal-plated polytetrafluoroethylene articles and method of manufacture

Claim 1

A process for coating a microporous polytetrafluoroethylene substrate with a conductive metal, the substrate having a microstructure of nodes interconnected with fibrils, and the conductive metal coating being continuous and substantially encapsulating at least some of the nodes and fibrils, the coated substrate being conductive along at least one surface and through at least a portion of the substrate volume beneath the one surface, the coated substrate retaining at least some of its porosity, the metal-coated substrate volume portion being hydrophilic and the non metal-coated substrate volume being hydrophobic, the process comprising the steps of: (1) cleaning the substrate; (2) saturating the substrate with an aqueous surfactant solution; (3) activating the surfaces of said substrate to be plated using a palladium/tin activator solution wherein the activating step includes as a final activating substep displacing the tin portion of said activator solution with an accelerator solution; (4) displacinng at least a portion of the accelerator using an aqueous medium; and (5) plating the substrate using an electroless plating solution.