Adsorption characteristic of copper ions and its application in electroless nickel plating on a hydrogel-functionalized poly(vinyl chloride) plastic

Abstract

A facile and palladium-free process for the electroless plating on poly(vinyl chloride) (PVC) plastic has been demonstrated. The process is based on the Cu adsorption capacity of semi-interpenetrating polymer network (semi-IPN) hydrogel chemically bonded to PVC surface via a simple and one-step approach that applying a chitosan/polyethylene glycol/glutaraldehyde system under mild stirring at room temperature. Therefore, electroless plating can be achieved in the following three steps, namely: (1) the functionalization of PVC by the semi-IPN hydrogel film (2) the adsorption and formation of the catalyst Cu0 on the PVC surface, and (3) the electroless nickel plating in plating bath. Batch adsorption experiments are conducted to determine the effects of pH, initial Cu2+ ions concentration and the dosage of crosslinking agent glutaraldehyde on copper adsorption and the surface resistance of the corresponding plated-PVC. The activated reaction progress and resulting nickel–phosphorus (Ni–P) layer were characterized by attenuated total reflection Fourier transform infrared, scanning electron microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The results show that the Cu nanoparticles chemisorbed on the functionalized PVC substrate, could effectively initial the subsequent electroless nickel plating; and a compact and continuous Ni–P layer with amorphous phase was successfully deposited on PVC by this process. Besides, the surface resistance of the plated-PVC as low as 0.5 Ω sq−1 showed an excellent adhesion with the PVC substrate proved by Scotch-tape test.