Dual photochromics-contained photoswitchable multistate fluorescent polymers for advanced optical data storage, encryption, and photowritable pattern

Stimuli-responsive fluorescent materials that can alternate their emission states on-demand are always desired in many applications. In this study, novel photoswitchable multistate fluorescent polymer (PMFP) was prepared via simple free-radical copolymerization of butyl acrylate (BA) and styrene (St) with two photochromic fluorescent monomers, i.e. sulfonyl diarylethylene-linked 4-hydroxybutyl acrylate (SDTE) and spiropyran-linked methacrylate (SP8). The PMFP displays excellent processability, due to its rational feed ratio of BA and St which result in the relative low glass transition temperature. By changing irradiation light, the non-fluorescent ring-closed spiropyran units and ring-opened diarylethylene moieties in PMFP can be selectively converted into their corresponding luminescence states. Furthermore, as a result of the controllable fluorescence resonance energy transfer (FRET) from the excited diarylethylene to the spiropyran moieties, the emission of the polymer in solution or film can be reversibly switched among distinguishable no-emission, red, and green fluorescence states. Moreover, the PMFP exhibits high brightness, high contrast, rapid photoresponse, and excellent photoreversibility. We also demonstrated that PMFP can be directly used for advanced high-density data storage, multilevel information encryption, and multicolor photorewritable pattern, as well as high-level anticounterfeiting.