Owing to its benefits to reducing paper production and consumption, ink-free rewritable paper has attracted great attention and it is desirable to develop rewritable paper based on its low-cost, robust, and environmentally benign color switching systems. Herein, we report the fabrication of a rewritable paper based on novel poly(vinylpyrrolidone)/hexatungstic acid (HTA) hybrids with fast dual-mode color switching. As-prepared rewritable paper shows fast and reversible colorless-blue or blue-colorless color switching upon photo- or hydroprinting, owing to the fast redox transformations of the unique HTA clusters. More interestingly, the rewritable paper can be used as a template for noble-metal reduction and the noble metal can be deposited on the reduced area of the paper to form well-ordered patterns in high resolution. This rewritable paper can be produced in large scale, and the composition can be facilely tuned with various polyoxometalates or polymers. It may not only be an attractive alternative to current paper prints but also be potentially used for noble-metal reduction to prepare photolithographic circuits and optoelectronic devices.
Keywords: fast color switching; hybrids; multifunctional rewritable paper; photochromic; polyoxometalates.