Photo-Activated In Situ Supramolecular Reversible Self-Assembly Based on Amphiphilic Calix[4]arene for Information Encryption

Photoacid sulfonato-merocyanine (MEH) serving as a photoisomer is added in mixed solution of amphiphilic calix[4]arene (SC4A8) and tetra-(4-pyridylphenyl) ethylene (TPE-4Py), which not only activates the in situ supramolecular self-assembly or disassembly, but also regulates two kinds of fluorescence emission. Benefiting from that MEH releases protons and becomes a ring-closed isomer spiropyran (SP) under 420 nm irradiation, TPE-4Py is protonated and then assembled with SC4A8 to form a supramolecular assembly with yellow fluorescence at 540 nm via electrostatic interactions. In the dark, SP changes to ring-opened MEH, realizing a spontaneous disassembly accompanied by fluorescence emission at 495 nm, and thus, a photo-activated reversible in situ supramolecular system is obtained successfully. Furthermore, Rhodamine B (RhB) acting as an energy acceptor is doped in the ternary supramolecular assembly, enabling the efficient energy transfer by the light irradiation. The formed tunable multicolor supramolecular assemblies have been successfully applied to the information encryption by 3D color codes.