Robust, intelligent photochromic cotton fabrics with superamphiphobicity and expedient UV detection ability.

Multifunctional photochromic cotton fabrics have enormous application potential in our daily lives, but still suffer from poor durability, slow coloration, tedious fabrication process, and short service life. The hydrophilic and polysaccharide characteristics of cotton fabrics make them vulnerable to bacteria adhesion and proliferation. Herein, intelligent photochromic cotton fabrics featured with durable superamphiphobicity are fabricated by in situ growth of ZIF-8 nanoparticles encapsulating spirooxazine (SP) photochromic dyes on the fabric surface, followed by low surface energy treatment using a fluorocarbon resin (FR) via a dip-coating method. The resultant SP@ZIF-8/FR cotton fabrics exhibit superamphiphobicity with contact angles of over 150° to both water and oils (surface tension ≥30 mN/m). When exposed to UV light, the fabric rapidly changes its color from white to blue within 10 s and fades in 2 min under visible room light. The developed SP@ZIF-8/FR coating is durable against numerous damages in daily usage, such as machine laundry, abrasion and UV irradiation, without losing photochromic and superamphiphobic properties. The high durability and excellent reversible color response allow the coated fabric to intuitively and quantitatively monitor outdoor UV intensity. Owing to the presence of ZIF-8, the treated fabrics also show excellent antibacterial property with antibacterial rates of over 99 % against both E. coli and S. aureus. The developed fabric coating can be engineered to visually assess the UV intensity in the outdoor environment.