Mechanically Tunable, Ultraviolet-Shielding, and Recyclable Smart Elastomers for Information Encryption via Fluorescence Switching and Shape Memory.

Styrene-b-butadiene-b-styrene (SBS) triblock copolymers represent a cost-effective, industrially mature candidate for smart elastomers, yet their weak physical cross-linking and poor UV stability hinder their utility in smart applications. Herein, multicomponent dynamic covalent photoresponsive elastomers are fabricated through Diels-Alder (D-A) chemistry, utilizing furan-functionalized SBS (SBS-Fu) cross-linked with maleimide-modified tetraphenylethylene (TPEDMI) and/or cellulose-based maleimide (ECMI). Synergistic optimization of composition and structure endows SBS-10Fu/TPEDMI10% with optimal mechanical properties, featuring an elongation of 820%, a tensile strength of 27.6 MPa, and a toughness of 83.1 MJ/m3. By integrating the aggregation-induced emission (AIE) of TPE, the photoinduced electron transfer (PET) effect of TPEDMI, and the thermoreversibility of D-A adducts, the resulting materials exhibit temperature/photoresponsive fluorescence modulation. The obtained over 99% UV-shielding efficiency can suppress the undesirable TPE photocyclization, thereby enabling information writing and erasing. When combined with favorable shape memory (Rf = 99.4%, Rr = 99.7%), a dual-mode encryption platform is further achieved. This study presents a comprehensive design framework for multifunctional elastomers targeting information encryption and smart systems.