Gel Materials with Rubber‐Rubbing‐Chromic Luminescence: A Portable Tool for On‐Spot Composing Highly Encrypted Information

Abstract Gels generally comprise different intermolecular noncovalent interactions for sustaining self‐assembled structures, which renders them sensitive to external stimuli, while simultaneously sacrificing their stimuli‐responsive selectivity. Supramolecular and polymeric gels are constructed here by the coassembly of a dipyridinil phenol as the crosslinker with the gelator counterparts. In these systems, an ordered multiple H‐bonded network facilitates a proton transferred tautomerization caused by the triboelectric effect of rubber rubbing, resulting in an unprecedented rubber‐rubbing‐chromic luminescence. This process is efficient and highly selective, as the friction with other materials fails to cause such a phenomenon. This results in a unique negative charge (−117 nC J⁻¹, exactly provided by the triboelectric effect of the rubber material) inducing the topochemical tautomerization at the gel level. Moreover, the polymeric gels exhibit superior mechanical properties and can be processed into a chalk‐like portable tool for writing. The composed luminescent information is also sensitive to rubber rubbing, featuring considerable practicability in on‐spot information encryption and anticounterfeiting.