Surface Modification of Biodegradable Magnesium Alloys

The use of self-assembling monolayers (SAM) of long chain carboxylic acids has a potential for designing specific interface architectures in degradable implants technology. In this paper, the native and anodically formed oxide films on the Mg‑alloy (AZ91D) surface were modified with the SAMs of palmitic acid (PA) and stearic acid (SA) to protect the alloy degradation in a physiological solution. X‑ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) were used to evaluate chemical composition, bonding modes of acids to the substrate, and structural properties (ordering and close-packing) of the surface layers. The results obtained by electrochemical impedance spectroscopy (EIS) have shown a beneficial effect of anodization and especially of the oxide layer modification by forming SAMs of PA and SA on the corrosion properties of AZ91D alloy in physiological solutions.