Hollow TiO 2 -enabled fluorescent anthracene polyimide composite coatings with visual monitoring and antibacterial functions

Medical antibacterial coatings can effectively inhibit the formation of bacteria and reduce the risk of transmission. However, the cracks and wear zones on the coating are not easily observable. Therefore, the polyimide (PI) loaded TiO2 composite film with visual functionality and antibacterial capability is developed in this work. Anthracene groups were introduced into the polyimide main chain as chromophores to form An-PI polymers with fluorescent properties. Then, hollow TiO2 was combined with An-PI base film through electrostatic spraying. Interestingly, the incorporation of TiO2 effectively enhanced the optical performance of the polymer film. Compared to the An-PI film, the photoluminescence (PL) intensity of the 6% TiO2 composite film increased nearly 55%. In addition, hollow-structured TiO2 served as carrier for antibacterial agents, endowing the resulting composite film with prominent antibacterial activity against Escherichia coli and Staphylococcus aureus. The bacteriostatic zone diameters were around 10 mm. The composite film showed favorable flexibility, with a tensile strength of 47.9 MPa and an elongation at break of 11.3%. The TiO2/An-PI composite film, which exhibits excellent optical, antibacterial, and mechanical properties, offers a promising strategy for the preparation and monitoring of protective coatings of medical devices.