Obtaining Reversible, Durable, High-Contrast Photochromism and Antibacterial Properties in a Flexible, Wearable Fiber Using Nanometer-Sized Polyoxotungstate

An approach to preparing a functional fiber has been developed. The method is carried out to link nanometer-sized polyoxometalate and cotton fabric by employing a cationic agent. Interestingly, the composite fabric exhibits a broad absorption peak in the visible range after irradiation, accompanied by obvious color changes from white to blue owing to electron transfer. The W(VI) transforms into a heteropoly blue W(V) rapidly (<5 s) in response to UV irradiation with a low-power UV (5 W), whereas its recovery seems slightly slow (5 h) in the air. Nevertheless, increasing the temperature can accelerate the fading process. Further, the continuous coloring–fading process presents outstanding repetition stability. Additionally, the composite fabric shows a degree of antibacterial property. Meanwhile, the physical properties indicate that multifunctional cotton retains natural features after chemical modification. In a word, the reversible photoresponsive cellulose fabric can be a promising candidate for developing a wearable and flexible sensor to monitor environmental changes.