Facile development of photochromic cellulose acetate transparent nanocomposite film immobilized with lanthanide-doped pigment: ultraviolet blocking, superhydrophobic, and antimicrobial activity.

Smart photochromic and fluorescent products can respond to an external stimulus by changing their colour and emission spectra with light. Here, we developed a simple formulation of an organic-inorganic nanocomposite photoluminescent cellulose acetate (CA) film based on immobilization of a lanthanide-doped pigment. Strontium aluminium oxide pigment doped with Eu2+ and Dy3+ (SAOED) exhibits an optimal excitation wavelength at 365 nm. For better fabrication of the multifunctional colourless pigment-cellulose acetate composites (CA-SAOED), the lanthanide-doped colourant must be well-dispersed physically without agglomeration. The fabricated photoluminescence cellulose film exhibited an excitation peak at 436 nm and two fluorescence peaks at 494 and 524 nm. The findings revealed that the originated nanocomposite films demonstrated improved superhydrophobic activity, high ultraviolet light protection and enhanced antibacterial activity without adversely influencing its native physico-mechanical characteristics. The films demonstrated fast and reversible photochromic responsiveness without fatigue during ultraviolet light irradiation.