A New Surface Etching Method Using MnO 2 /H 2 SO 4 Colloid for Adhesion Improvement of Epoxy Polymer

Abstract A new surface etching method using MnO2/H2SO4 as the etchant to improve the adhesion between an epoxy polymer surface and a metallic layer, was studied. The effects of bath temperature, etching time and H2SO4 concentration on the surface topography and chemical properties were investigated. After the etching treatment of the MnO2–H2SO4 colloid, not only did the surface roughness increase remarkably, but also the surface of epoxy became hydrophilic and the contact angle of the epoxy surface was also decreased from 93.5° to about 8.0°. The X-ray photoelectron spectroscopy analysis indicated that as a result of the etching treatment, hydroxyl, carbonyl and carboxylic acid groups formed on the epoxy surface. The adhesion strength was markedly enhanced with the appropriate etching treatment, which was attributed to the improvement of the surface roughness and the increased hydrophilicity.