Effect of codeposition of polymer on the morphology of electrodeposited copper

Poly(4-vinyl pyridine-co-methyl methacrylate), which is soluble in water in its protonated form and insoluble as a neutral molecule, has been synthesized and introduced into an acid bath for copper deposition. Potential-sweep investigations have shown that the copolymer affects the electrocrystallization of copper on graphite by delaying nucleation even before conditions for codeposition of the polymer are reached. At overpotentials at which the diffusion limiting current of copper is reached and hydrogen evolution starts, alkalinity at the electrode surface causes precipitation of the polymer. This is found to affect the resistivity of the deposit. Electron microscopy revealed that under such conditions copper is deposited in the form of globular particles, the size of the globules being in the micron range and decreasing with increasing overpotential. © 1979 Chapman and Hall Ltd