Complex-induced coupling effect: adhesion of some polymers to copper metal promoted by benzimidazole

Abstract

Improved adhesion of a polymer with polar functional groups to copper has been achieved by pretreating the copper surface with benzimidazole solution. The adhesion strength was found to increase by two to three times. The coupling mechanism and interfacial structure of the copper-polymer composite have been investigated by X-ray photoelectron and Fourier transform infrared relection-absorption spectroscopies. We found that benzimidazole reacted with copper metal in the presence of oxygen to form benzimidazolato copper(+1), which covered the surface in the form of a thin polymeric layer. As the surface was exposed to air, some of the cuprous cations were oxidized to cupric ions. When poly(vinylpyridine) was coated onto the pretreated surface, the nitrogen atoms of the side groups of the polymer chains co-ordinated to the cupric cation to form interfacial bonding connecting the polymer to the copper metal.

Keywords:

• Copper metal
• poly(vinyl pyridine)
• benzimidazole
• coupling agent
• interfacial bonding
• adhesion promotion