Influence of composition and microstructure of ZnxTiyO thin films on their chemical resistance and antifungal properties

Durable and chemically resistant antimicrobial coatings may be beneficial in healthcare and industrial settings. This study explores three strategies to develop chemical-resistant antifungal thin films: ZnO/TiO₂ bilayer with post-deposition thermal treatment, Ti x Zn y O thin films deposited using a zinc target with titanium pellets, and Zn x Ti y O thin films using a titanium target with zinc pellets. The influence of their chemical composition and microstructure was assessed based on chemical resistance to commercial detergents and antifungal activity against the fungal model pathogen Candida albicans . ZnO/TiO₂ and Ti x Zn y O films showed lower performance in both chemical resistance and antifungal activity, which may be attributed to lack of diffusion between layers and lower Ti concentration, respectively. In contrast, Zn x Ti y O thin films allowed controlled tuning of chemical, structural, and morphological properties. As the Zn/Ti atomic ratio increased, Zn-doped TiO 2 amorphous and dense structures evolved into Ti-doped ZnO crystalline structures and columnar-like morphologies. Zn/Ti = 7 represented a transitional behavior in both structural features and antimicrobial performance. Ti-doped ZnO films exhibited enhanced antimicrobial performance (80 % reduction of fungal growth), likely driven by Zn 2+ ions release, despite reduced chemical resistance. This behavior contrasts with that of TiO 2 and Zn-doped TiO 2 films. Zn x Ti y O with Zn/Ti = 20 and ZnO films showed promise as antifungal coatings for common surfaces. • Varying target configuration in magnetron sputtering tunes Zn x Ti y O films features. • Zn-doped TiO 2 thin films transitioned to Ti-doped ZnO as the Zn/Ti ratio increased. • Higher Zn/Ti ratios enhanced antifungal activity but reduced chemical resistance. • Zn x Ti y O (Zn/Ti = 20) and ZnO thin films show potential as antifungal coatings.