Effect of the Preparation Method on the Properties of Eugenol-Doped Titanium Dioxide (TiO2) Sol-Gel Coating on Titanium (Ti) Substrates

The focus of this study was the preparation of sol–gel titanium dioxide (TiO2) coatings, by the dip-coating technique, on Ti6Al4V (TiGr5) and specific Ti implant substrates. In order to confer antibacterial properties to the layers, Eugenol was introduced in the coatings in two separate ways: firstly by introducing the Eugenol in the sol (Eug–TiO2), and secondly by impregnating into the already deposed TiO2 coating (TiO2/Eug). Optimization of Eugenol concentration as well as long term were performed in orderboth short- and long-term Eugenol concentration was performed to investigate the prepared samples thoroughly. The samples were investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves (PDP). To investigate their resistance against Gram-negative Escherichia coli bacteria, microbiological analysis was performed on coatings prepared on glass substrates. Structural studies (FT-IR analysis, Raman spectroscopy) were performed to confirm Eugenol–TiO2 interactions. Coating thicknesses and adhesion were also determined for all samples. The results show that Eug–TiO2 presented with improved anticorrosive effects and significant antibacterial properties, compared to the other investigated samples.