Synthesis and Photocatalytic Antibacterial Properties of Poly[2,11′-thiopheneethylenethiophene-alt-2,5-(3-carboxyl)thiophene]

Designing new antimicrobial materials that are effective under visible light irradiation without leaching toxic ions is a current challenge for effective disinfection. This work examined the synthesis and characterization of a polymeric system poly[2,11′-thiopheneethylenethiophene-alt-2,5-(3-carboxyl)thiophene] (PTET-T-COOH) with broad light absorption. Its photocatalytic disinfection performance against Staphylococcus aureus and Streptococcus suis were evaluated, showing >99.9% inactivation for both bacteria under visible light irradiation at a low concentration of PTET-T-COOH (0.1 mg/mL). The active species generated and responsible for the photocatalytic disinfection were confirmed to be singlet oxygen and free electrons by using chemical scavengers and electron spin resonance spectroscopy (ESR). PTET-T-COOH demonstrated excellent chemical stability under visible light irradiation, with the carboxyl group providing a possibility for chemical bonding to suitable functionalities for the development of antibacterial coatings.