Highly porous copper with hollow microsphere structure from polystyrene templates via electroless plating

Hollow copper microspheres with pore size about 3 μm and spherical shell around 150 nm were successfully prepared by electroless plating using polystyrene (PS) as sacrificial templates and the kinetics were studied concerning the empirical rate law. The effects of plating bath composition on the amount, microstructure and composition of the deposited copper shells were investigated. pH was the most important factor for copper deposition rate and amount of copper deposits. The amount of by-product Cu₂O decreased with increasing pH values and the deposited copper agglomerated when pH value reached 13.41. The addition of stabilizers (2, 2-bipyridine, potassium ferrocyanide and methanol) had a very negative effect on the microstructure of the deposited copper shells. PS templates were removed by sintering and the remanent copper deposits with high purity maintained good spherical shell structure. In addition, the kinetic equation of electroless copper plating (ECP) using PS as the substrate was determined and the activation energy (Ea) was 59.77 kJ •mol^-1. The prepared hollow copper microspheres with high porosity are ideally suitable for synthesizing energetic materials and this method might also be used for fabricating other hollow metal microspheres.