Pore structure of ethyl cellulose (EC)/graphene oxide (GO) composite film investigated by electrochemical impedance spectroscopy

Ethyl cellulose (EC) is one of the important coating materials for the short‐term protection of precious metals and jewellery. In this study, graphene oxide (GO) was introduced in EC films, and electrochemical impedance spectroscopy (EIS) was utilized to probe the ion permeation through the films. EIS results demonstrate the film resistance increased with the GO content from 0 to 1 wt.%, and decreased with the GO content from 1 to 4 wt.%. It indicates that the ion penetration first becomes difficult and then easier with the increase in GO content. SEM results reveal that the pore sizes of the doped EC composite films first decrease and then increase with the increase of GO content. Additionally, water contact angle results indicate that introducing GO enhanced the surface hydrophilicity of the EC composite film. The tensile test shows that the EC/GO composite film achieves the best mechanic property at the GO content of 1 wt.%. These findings indicate that the pore structure of EC could be adjust by GO platelet, which could be an easy method to modify the ion barrier through EC film.