Reconfigurable photoswitchable multistate fluorescent polymer-based information encryption toolbox

High-performance information encryption materials are crucial for developing advanced technologies that prevent information leakage and combat fraud. These materials must be robust, intelligent, and easily programmable. To meet these criteria, we developed an information encryption toolbox based on a series of novel self-healing photoswitchable dual (P1 and P2) and multistate (P3) fluorescent polymers using two photochromic fluorescent diarylethenes, i.e., 4-hydroxybutyl acrylate link 1,2-bis(2-methyl-1-benzothiophene-1,1-dioxide-3-yl)perfuoro-cyclopentene (SDTE), 4-(acryloyloxy)butyl 4-oxo-4-butanoate link 2,3-bis (2-methylbenzo[b]thiophen-3-yl)-5,6-dihydro-4H-thieno[2,3-b]thiopyran-4-one (BTBA) and hydrogen-bonding units, i.e., 2-ureido-4[1H]-pyrimidinone (UPy). Upon irradiation with different wavelength lights, P1/P2 can be alternated between green/red and quenched states, while P3 can be switched among red, green, and quenched states. Using these polymers to fabricate pixel units can produce reconfigurable patterns and codes displaying good mechanical properties and excellent optical characteristics, including rapid photoresponsiveness, robust photoreversibility, superior fluorescent thermal stability, and strong resistance to acid and base corrosion. Furthermore, we also demonstrated the immediate application opportunities of our toolbox in three-dimensional-code arrays and quick response codes.