Electrical-responsive biocompatible coatings for highly corrosion-resistance and self-healing performance on AZ31 Mg alloy

An electrically stimulated smart 8-hydroxyquinoline loaded poly(3,4-ethylenedioxythiophene) (8-HQ@PEDOT) nanocapsules are fabricated via emulsion polymerization. SEM and TEM images indicate that the 8-HQ@PEDOT nanocapsules display a hollow nanosphere structure with an average diameter of 300–500 nm. TGA results confirm the loading ratio of 8-HQ inhibitors in 8-HQ@PEDOT nanocapsules is approximately at about 8.2 %. Furthermore, increased concentrations of the 8-HQ inhibitors are achieved after applying higher negative voltages, reflecting its evident electrical-responsive features. Afterward, 8-HQ@PEDOT nanocapsules are incorporated into the polylactic acid (PLA) coatings and deposited on the AZ31 Mg alloy surface. The corrosion resistance and self-healing performance of the PDA/8-HQ@PEDOT/PLA coatings are explored by electrochemistry tests. The EIS tests and hydrogen evolution test indicate that the PDA/8-HQ@PEDOT/PLA coatings show enhanced corrosion protective performance and remarkable self-healing ability during the immersion period. In addition, a larger number of MG-63 cells can survive on the coating surface and the hemolysis rate value of 2.68 % confirms their indicating the excellent biocompatibility of PDA/8-HQ@PEDOT/PLA coatings. The designed PDA/8-HQ@PEDOT/PLA coatings possessed remarkable anti-corrosive, self-healing and biocompatibility, which has great potential in the bio-implant material applications field.