EIS study on the barrier properties of silicone-epoxy coatings enhanced by different PDA-BN@ZnO nano-pigment contents

To evaluate the barrier properties of the composite coatings reinforced by PDA (polydopamine)-BN@ZnO nano-pigments, the correlation between electrolyte transport characteristics and different nano-pigment contents in the composite coatings was studied. The electrochemical response of composite coatings was mainly controlled by non-Faraday process. A two-layer model based on Young's impedance was established to fit the non-Faraday process of the composite coatings from the 6th day of immersion. The coating resistivity varying with electrolyte transport could be used as a key parameter to describe the barrier properties of the coatings. At the same time, the explanation that different contents of nano-pigments enhance or weaken the barrier performance of composite coatings was given, that is, the nanoconfinement effect of the polymer under the effect of nano-pigments.