Chitosan-sodium alginate-based coatings for self-strengthening anticorrosion and antibacterial protection of titanium substrate in artificial saliva

A self-strengthening coating with silver nanoparticles (Ag NPs) doped chitosan (CHI) and sodium alginate (SA) polyelectrolytes was constructed on the surface of polydopamine (PDA) coated Ti substrate by a layer-by-layer assembly method. The PDA coating exhibited an excellent bond with Ti substrate, and also can uniformly deposit Ag NPs via a mild method without introducing any exogenous reductant. The CHI coating was assembled through a spin-coating method for controlling Ag+ release. The SA was introduced to enhance the anticorrosion performance by forming calcium alginate (CA) in a corrosive medium. The corrosion protection was investigated with electrochemical impedance spectroscopy and polarization curves tests in fluorine-containing artificial saliva. During immersion, the charge-transfer resistance and the protection efficiency (LATIN SMALL LETTER ENG) presented a continuous increase with the immersion time, demonstrating that this coating possessed a remarkable self-strengthening capability, and the compositions of the outermost film changed from SA to CA with the Ca2+ cations of the corrosive medium as a crosslinker by SEM and EDS analysis. Furthermore, the LATIN SMALL LETTER ENG remained up to 96.8% after immersion of 30 days, and then the coating also displayed a distinct inhibition zone on S. mutans. These results prove this coating possesses an excellent anticorrosion performance and antibacterial property.

Automated summary

In this study, a self-strengthening coating was successfully constructed using silver nanoparticles, chitosan, and sodium alginate, which exhibited enhanced corrosion resistance and antibacterial properties. The coating continuously strengthened in corrosive medium, showing high protection efficiency.