EQCM Study of the Influence of Copper Ions on the Adsorption of Polyethylene Glycol and Bis(sodiumsulfopropyl) Disulfide at a Copper Cathode

An electrochemical quartz crystal microbalance (EQCM) has been used to examine the role of polyethylene glycol (PEG) and bis(sodiumsulfopropyl) disulfide (SPS) in the deposition of copper from acidified aqueous sulfate solutions containing chloride ions. Neither PEG nor SPS was observed to adsorb on copper at cathodic potentials in the absence of copper ions in solution. When a small amount of copper (principally Cu (II)) was introduced into solution by a double potential step, the adsorption of PEG was observed, as was the inhibition of that adsorption by SPS