Heat treatment of Hexa-Methylene Diamine Tetra-Methylene Phosphonic Acid (HMDTMPA) coating on biodegradable Mg to improve corrosion resistance and bioactivity

Since the bioactive surface needs hydrophilic coating; and the high corrosion resistance needs a hydrophobic one, it is a challenge to design a bioactive film that exhibits corrosion protection. In this article, Hexa-Methylene Diamine Tetra-Methylene Phosphonic Acid (HMDTMPA) film was deposited on Mg substrate at different heat treatment conditions. The heat-treated films at 150°C showed remarkable anticorrosion performance about five times the non-heated film. In addition, bioactivity character such as live cells attraction was noticed due to the increase of P–O groups that compensated the decrease of O–H groups in the film structure. Through the post-heat treatment, we were able to provide a new insight towards understanding how particular functional groups (OH) can modify the organic coating quality. The master key here is the formation of a stable film of chloroapatite that plays dual functions to inhibit the corrosive ions penetration and improve the bioactivity to attract the living-cell.