Time-Dependent Information Encryption Using a Supramolecular Polymer Gel Based on a Pillararene

With the rapid development of information technology, information security has become a hot topic of global concern. Many efforts have been devoted to developing intelligent materials for safeguarding information. Time-dependent information encryption based on supramolecular polymer gel (SPG) materials has many advantages including intrinsic stimuli responsiveness, good processability, excellent self-healing property, and so on. Herein, we report a time-dependent information encryption material constructed by a SPG with tunable fluorescence emission based on a pillararene. A bipyridine derivative-containing fluorescent polymer P1 and a pillararene-containing polymer P2 were prepared. P1 underwent a fluorescence emission decrease with a red shift from blue to blue-green after adding the acid due to the protonation of its bipyridine group. The protonated form of P1 was denoted as P1H. When P1H was mixed with P2, a SPG formed, accompanied by quenching of the blue-green fluorescence due to the host–guest interactions between a pillararene and the protonated bipyridine derivative guest. Intriguingly, adjusting the concentration of the acid added to the SPG can control the rate of fluorescence color change, enabling dynamic information encryption that can vary over different time scales. Due to the reversible property of this supramolecular system under external stimuli, the decrypted information could be encrypted again by treating with base or waiting for a period of time without any treatment, avoiding the leakage of the stored information and upgrading the information security.