Electrophoretic deposition, microstructure and selected properties of nanocrystalline SnO2/Sr enriched bioactive glass/chitosan composite coatings on titanium

Abstract

The presented study aimed to develop composite chitosan-based coatings with the addition of bioactive sol-gel glass enriched with Sr and potentially antimicrobial SnO2 nanoparticles on titanium substrates by cathodic electrophoretic deposition (EPD). The effect of suspension's chemical composition and pH level on their stability were investigated and adjusted to obtain macroscopically homogenous coatings. The electrosteric mechanism was responsible for coatings deposition. The dense coatings with excellent adhesion to the titanium and a well-developed surface including agglomerates of sol-gel glass and SnO2 particles were developed. It was shown that the roughness of the coatings was higher than for the underlying Ti substrate. All coatings demonstrated moderate wettability, 40 % higher in contact with water and 66 % higher in contact with non-polar liquid than for the pure Ti substrate. The surface free energy of the uncoated Ti substrates was about 32 % lower compared to the coated titanium. Furthermore, it was demonstrated that composite coatings containing SnO2 NPs, improve the electrochemical corrosion resistance of Ti substrates in Ringer's solution. Owing to the high adhesion strength of coatings, their morphology, wettability, and high corrosion resistance, they appear to be noteworthy in the future development of bioactive enhanced titanium surfaces with antibacterial properties.