Colored Coating of Ni/Organic Pigment Composite Films in Two Steps Using a Surfactant Containing an Azobenzene Group

Abstract

Highly reflective, uniform and stable thin composite films of Ni-organic pigment were prepared in two steps. First, a thin film of organic pigment was prepared on a nickel substrate by electroless plating of this pigment by reduction of a nonionic azo-surfactant (AZPEG, 1). Electrodeposition of nickel on the substrate covered with this pigment film was then carried out by controlled potential electrolysis in a chloride bath at 25°C. The concentration of nickel ion and the pH of the bath were found to have great influence on the preparation of uniform composite films. The volumetric content of pigments in the composite was found to be very high (84. 8 vol%). The adhesion of these composite films to the substrate was found to be much stronger than that of the pigment film alone. Using polystyrene, the adhesion of the films was found to be further improved by thermal treatment.