A Study on the Lowering of the Water Sorption of the Epoxy Coating Using Electrochemical Impedance Spectroscopy

The lowering of the water sorption of the epoxy coating by replacing the hydroxyl groups in the coating with acetoxy groups has been studied using electrochemical impedance spectroscopy. The experimental results show that the lowering of the water sorption at the coating/substrate interface of the novel epoxy coating is much larger than that in the bulk of the coating. This may be attributed to the surface bond formation which makes the orientation of the acetoxy groups at the interface different from that in the bulk, and causes the coating near the interface less hydrophilic.