THE INFLUENCE OF INTERFACIAL WATER ON NONMECHANICAL ADHESION OF COPPER SULFIDE AND COPPER COATINGS TO IMPACT-RESISTANT POLYSTYRENE

The influence of the storage time on the adhesion of CuS and electroless copper coatings to impact-resistant polystyrene (IRP) has been investigated. Adhesion of a non-mechanical nature was obtained by combining a surface treatment of IRP at room temperature in a xylene emulsion and a short-term (10 s) treatment at room temperature in a H2SO4-CrO3 solution. The adhesion value is close to zero immediately after depositing CuS and Cu coatings. However, the adhesion value increases with the storage time and the peel value of the coatings (P) becomes limited by the polymer's cohesive strength. The increase in adhesion in the course of exposure of the sample to the air is the result of water removal from the coating-polymer interface. It has been shown that besides evaporation, interfacial water may be removed from the interfacial region by interfacial forces, most likely of physical nature.