Cellulose microfibers (CMFs) as a smart carrier for autonomous self-healing in epoxy coatings

Abstract

Synthesized cellulose microfibers (CMFs) were used as a smart carrier for the loading of inhibitor-dodecylamine (DOC) and inhibitor/self-healing polyethyleneimine (PEI). The loaded CMFs were thoroughly dispersed into the polymeric matrix to develop smart self-healing epoxy coatings. Field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR), and thermogravimetric analysis (TGA) confirm the successful loading of inhibitors and self-healing agents on CMFs. UV-vis analysis indicates the pH sensitivity and time-dependent release of the loaded inhibitor. The inhibition mechanism and chemical interaction of the protective surface film layer on steel elucidated their role in autonomous self-healing. The electrochemical impedance spectroscopy (EIS) measurements for a scratched coating sample demonstrate the increase in the impedance value for the smart coatings as compared to the reference coatings. This improvement is attributed to the efficient release of corrosion inhibitor and the development of a stable, protective film due to the self-healing effect. The synergetic effect of DOC and PEI revealed the self-healing ability of a smart epoxy coating.