Reversible Emitting Anti‐Counterfeiting Ink Prepared by Anthraquinone‐Modified <i>β</i>‐Cyclodextrin Supramolecular Polymer

Abstract

Intelligent fluorescent materials have been paid more and more attention due to their wide application in information encryption and anti-counterfeiting materials. Herein, a supramolecular polymer is constructed through the host-guest interaction of anthraquinone-modified <i>β</i>-cyclodextrin (AQ-<i>β</i>-CD) in aqueous solution. Thanks to the hydrophobic microenvironment of the cyclodextrin cavity and the shielding effect on oxygen molecules, the anthraquinone group, as the guest molecule, can rapidly produce 9,10-anthracenediol (QH₂) with strong fluorescence by photoreduction. Interestingly, the generated anthracenediol group is still sensitive to oxygen and can be converted to anthraquinone by oxygen. Significantly, aqueous solution of AQ-<i>β</i>-CD supermolecular polymer is used as emitting ink, which decrypts the information by ultraviolet light and encrypts the information in the air.