Polyimide/titanium dioxide self-cleaning nano-hybrid films with high photocatalytic properties

Self-cleaning films are considered an emerging paradigm of environmentally functional materials. Enhancing the photocatalytic activities of self-cleaning film is a viable strategy for improving its antifouling characteristics. In this work, a polyimide/titanium dioxide (TiO2) film (PI/TiO2) film was developed by casting a mixture of polyamic acid solution and TiO2 hydrosol with a subsequent thermal imidization. TiO2 with a concentration of 1, 3, and 5 ​wt% was successfully incorporated into the PI matrix and was equally distributed in nanometer size in the PI/TiO2 nano-hybrid films. The addition of TiO2 into the film significantly improved its catalytic performance as indicated by the photocatalytic degradation of methylene blue and resazurin solution, suggesting a good self-cleaning property for antifouling applications. In addition, the thermal and mechanical stability of the PI film were improved with the addition of TiO2. After eight cycles, the PI-TiO2 films also demonstrated excellent cycling stability. This study introduces a novel self-cleaning film family composed of PI/TiO2 nano-hybrid film and emphasizes the engineering potential of photocatalytic materials in the context of self-cleaning film.