Crystalline Confinement of Dynamic Room‐Temperature Phosphorescent Hydrogels: A New Paradigm for Synergistic Enhancement between Lifetime and Flexibility

Abstract Dynamic room‐temperature phosphorescence (RTP) materials present promising applications in optoelectronic fields. However, conventional dynamic RTP hydrogels typically suffer from an inherent performance trade‐off, where enhancement of flexibility comes at the expense of phosphorescence lifetime and vice versa. Herein, a universal crystalline confinement strategy is reported to overcome this fundamental limitation by employing ionic comonomers to regulate crystalline domains. By incorporating ionic comonomers such as 3‐sulfopropyl methacrylate potassium salt (SPM), the hydration competition and disruption of crystalline packing enable precise control over crystal dimensions, yielding hydrogels with exceptional stretchability (634%) and toughness (12 MJ m −3 , 107‐fold improvement). The ionic comonomers also serve as electrostatic anchoring sites for chromophores, stabilizing triplet excitons and significantly prolonging the phosphorescence lifetime to 598.79 ms. This approach overcomes traditional trade‐offs between flexibility and phosphorescence lifetime, demonstrating broad applicability across various ionic comonomers with ≈100‐fold toughness enhancements and prolonged phosphorescence lifetime. These results establish a generalizable framework linking crystalline domain dynamics with photophysical properties in dynamic hydrogels. The design opens avenues for advanced dynamic RTP materials in stretchable optoelectronics, dynamic encryption, smart sensors, and reagent thermal history monitoring.