ABSTRACT
Surface graft copolymerization is a very versatile method for redesigning the molecular functionality of most polymer surfaces. Using the inert fluoropolymers as examples, it is demonstrated in the present work that strong adhesion between two polymer surfaces, or between a polymer and a metal surface, can be achieved through the intelligent choice of the graft chain and the graft configuration at the polymer surface and interface. In the ‘IntelliGraft-I’ method, a simple one-step process of surface thermal graft copolymerization of a plasma-pretreated fluoropolymer, such as a poly(tetrafluoroethylene) (PTFE) film, with simultaneous lamination to a metal, such as a Cu foil, was carried out at the temperature of 120°C in the presence of a functional monomer. In the ‘IntelliGraft-II’ method, the plasma-retreated polymer substrate was subjected to thermally or UV-induced surface graft copolymerization with a functional monomer. The process was completed after metallization and thermal curing of the metal–polymer interface. Secondary graft copolymerization and further plasma treatment prior to metallization resulted in the further enhancement of the adhesion strength. Both IntelliGraft’ methods gave rise to polymer-metal laminates of high adhesion strengths with thin ‘adhesion promoting’ layers. In most cases, the polymer–metal joints delaminated by cohesive failure in the polymer in T-peel tests.
