M⧹TiO2 (M = Au, Ag) transparent aqueous sols and its application on polymeric surface antibacterial post-treatment

In this paper, we reported a simple and mild chemical method for synthesis of crystalline metal⧹TiO2 (M=Au, Ag) transparent aqueous sols at low temperature (80°C). It should be found that the as-synthesized metal⧹TiO2 sols could easily be coated on the flexible PET surfaces of the through the as-developed electroless-plating-like solution deposition (EPLSD) procedure. The as-prepared metal⧹TiO2 sols and related flexible thin film were characterized by TEM, SEM, XRD, UV–vis, and FTIR analysis. The results showed that the Au and Ag nanoparticles can significantly improve the optical absorption properties of TiO2 due to the surface plasmon generated by the noble metal, which in turn enhanced the photo-induced antibacterial performance of the as-prepared metal⧹TiO2 flexible film. Moreover, the photo-generated electrons could transfer between the metal and titanium dioxide under different irradiation (ultraviolet or visible light), which could significantly reduce the recombination of photo-induced electrons and holes, resulting in the better photo-induced antibacterial performance. Therefore, the EPLSD procedure may be used as a general polymeric surface antibacterial post-treatment procedure for preparing the metal⧹TiO2 flexible film because of the noble metal enhanced antibacterial performance.