Porous PEI Coating for Copper Ion Storage and Its Controlled Electrochemical Release

Abstract The use of copper‐based chemicals to prevent biological growth has been widely practiced in the past. However, leaching of the copper has increased concentrations in ports and marinas, posing a risk to marine life and the environment. It is therefore timely to develop a sustainable antibiofouling coating that could replace conventional copper‐based paints. Herein, the use of cross‐linked polyethylene imine (PEI) coated on conducting carbon cloth electrodes as a material that can absorb copper from seawater and allow for controlled electrochemical release of copper as a biocide to prevent biofouling is proposed. The results show that the porous coating can store and release copper ions over multiple cycles by passing only 1 mA cm −2 current density through the electrode in artificial seawater. This could enable a closed‐cycle, copper‐based antifouling coating, i.e., a coating that uses the well‐established biocidal activity of copper, but without any net release to the ocean.