Photochromic performance of hydrogel based on deep eutectic solvent induced water soluble Cu-doped WO3 hybrids with antibacterial property

A novel fast photoresponse and self-fading photochromic hydrogel system was fabricated based on Cu-doped WO 3 , which prepared by employing DESs as co-solvent. The photochromic hydrogel displayed remarkable antibacterial ability and non-cytotoxicity, great potential in the applications of stimuli-responsive materials such as smart windows, repeatable erasing paper and photochromic sensors. • Deep eutectic solvents (DESs) as a green co-solvent was employed to prepare Cu-doped WO 3 photochromic materials with excellent water solubility. • The fabricated P(AM-HEA)-Cu-WO 3 -X photochromic hydrogels exhibit rapid photoresponse and enhanced self-fading rate. • The deep-blue colored P(AM-HEA)-Cu-WO 3 -25% hydrogel could come back to its original colorless state within 40 min. • The mechanism of photochromic and self-fading behaviors for P(AM-HEA)-Cu-WO 3 -X photochromic hydrogels was detailed analyzed. • The remarkable antibacterial performance and cell viability possessed in hydrogels also confirmed. A novel photochromic and self-bleaching hydrogel was prepared based on the Cu-doped tungsten oxide (WO 3 ) hybrid encapsulated in the co-polymer matrix polymerized using acrylamide (AM) and hydroxyethyl acrylate (HEA) as monomers. The Cu-WO 3 -25% hybrid was generated by introducing Cu species into the lattice of WO 3 with hexagonal-like prismatic structure and acted as light absorber. Given that WO 3 and Cu-doped WO 3 hybrids possess superior water solubility by using water and deep eutectic solvents (DESs, ChCl:EG) containing sufficient hydrogen bond as co-solvent, the high transparency of 90% of the hydrogels was achieved. As compared with P(AM-HEA)-WO 3 -based hydrogel, the P(AM-HEA)-Cu-WO 3 -X hydrogel exhibited the enhanced coloration degree under UV irradiation. The P(AM-HEA)-Cu-WO 3 -25% photochromic hydrogel changed from colorless to blue immediately once illuminated by UV light, and turns into dark-blue with the irradiation time going on. The self-bleaching process indicates it only takes 40 min for the P(AM-HEA)-Cu-WO 3 -25% hydrogel to return to the original colorless transparent state. Furthermore, the hydrogel systems exhibit efficient antibacterial activities against bacteria of both E. coli and S. aureus , accompanying with outstanding biocompatibility. As such, the fabricated hydrogel demonstrates rapid photoresponse, self-bleaching process, superior antibacterial performance, and cell viability, showing a great potential application as stimuli-responsive materials.