Effects of Additives on Cu-MWCNT Composite Plating Films

The effects of plating bath additives on copper-multiwalled carbon nanotube (MWCNT) composite platings were studied. An acidified cupric sulfate electrolyte containing MWCNTs and polyacrylic acid as a dispersing agent was used as the base plating bath. Chloride ions (Cl-), poly(ethylene glycol), bis(3-sulfopropyl)disulfide (SPS), and Janus green B (JGB) were examined as additives. The surface morphologies and cross-sectional microstructures of the electrodeposited films were investigated, and the MWCNT content of the films was determined. Furthermore, the electrical resistivity and field emission properties of the films were evaluated. The simultaneous addition of Cl-, SPS, and JGB to the base plating bath was effective for forming smooth Cu-MWCNT composite films with a high MWCNT content over a wider range of current densities. The optimal bath composition was 0.85 mol dm(-3) CuSO4 center dot 5H(2)O+0.55 mol dm(-3) H2SO4+100 ppm PA5000+2 g dm(-3) MWCNTs+2 ppm SPS + 2 ppm JGB +50 ppm Cl-. Cu-MWCNT composite films containing 0.15-0.33 mass % MWCNTs with smooth surface morphologies were formed in the current density range of 0.5-5 A dm(-2). The electrical resistivity of the films was around 2 mu cm, and they showed obvious field emission properties.