A study of the environmentally friendly polycarbonate surface etching system containing H₂SO₄–MnO₂ colloid

Abstract

In this paper, an environmentally friendly etching system containing H₂SO₄–MnO₂ colloid was used to investigate surface etching for polycarbonate (PC). The effects of swelling condition, H₂SO₄ concentrations and etching times on surface topography and surface roughness were studied. With the etching treatment, the surface average roughness (R _a) of PC substrates increased from 3 to 76 nm and the adhesion strength between the electroless copper and PC substrate reached 1.08 KN/m. Surface chemistry of PC substrates was investigated by the contact angle measurement and X-ray photoelectron spectroscopy spectra (XPS). After the etching treatment, PC surface became hydrophilic and the contact angle decreased from 95.2 to 39.6^o. XPS analyses indicate that hydroxyl and carboxyl groups are formed on the PC surface as a result of the etching treatment, which improve the adhesion strength between PC substrate and electroless copper film.

Keywords:

• PC surface etching
• surface roughness
• electroless copper plating
• adhesion strength

Acknowledgements

The authors would like to thank Research Fund for the National Natural Science Foundation of China (No. 21273144), Doctoral Program of Higher Education of China (No. 20110202110004) and Changjiang Scholars and Innovative Research Team in University of China (IRT1070) for supporting this research.