Visible-light-induced bactericidal properties of a novel thiophene-based linear conjugated polymer/TiO 2 heterojunction.

The low utilization of visible light and the fast recombination of photogenerated electron-hole pairs are the two intrinsic defects that have hindered the antibacterial applications of TiO 2 . The addition of organic photocatalytic agents to form heterojunctions with TiO 2 powder can effectively address these problems. A novel linear conjugated polymer poly[(thiophene-ethylene-thiophene)-thiophene-3-carboxylic acid decyl ester] (PTCD) was successfully synthesized via Stille coupling polymerization. PTCD and TiO 2 can form a heterojunction photocatalyst (PTCD/TiO 2 ), and this product was characterized using NMR and XRD. The UV-vis spectra showed that the absorption edge of the PTCD/TiO 2 heterojunction extends to approximately 700 nm, which indicates that the visible-light utilization is greatly improved. Staphylococcus aureus ( S. aureus ) was selected as the target organism to test the photocatalytic antimicrobial activity of the material. Photogenerated electrons can undergo directional transmission of the PTCD polymer to TiO 2 on the PTCD/TiO 2 heterojunction to realize excellent antibacterial properties. With an optimized PTCD loading ratio of 30%, PTCD/TiO 2 showed an antibacterial rate that was 14.5 times greater than that of pure TiO 2 in 4 h under visible-light irradiation.