High‐Security Plastic Enabling Integrated Holographic and Fluorescent Dual‐Mode Images

ABSTRACT High‐security anticounterfeiting materials require the crosstalk‐free integration of multiple optical functionalities within a single plastic platform. Holographic patterning offers exceptional information density and angular selectivity, while its performance is fundamentally limited by refractive‐index modulation. Here, we rationally construct a polyurethane elastomer (IPUU) at the molecular design level by incorporating highly extensible polyether soft segments and alicyclic hard segments with suppressed π‐electron delocalization, which enlarges the molecular volume, reduces the polarizability density, and yields an intrinsically low refractive index of 1.42. Benefiting from the pronounced refractive‐index contrast established between the low‐index matrix and the high‐index monomer during photopolymerization, the resulting IPUU‐based holographic plastic achieves a diffraction efficiency as high as 96%. Meanwhile, the introduction of multiple acylsemicarbazide and urethane moieties constructs a dense yet reversible hydrogen‐bonding network, imparting excellent elasticity, shape‐memory behavior, and thermally activated self‐healing capability, while also providing a favorable microscopic environment for reactant migration and network reconfiguration during photopolymerization. Notably, fluorescent patterns can be independently encoded within the same transparent film, enabling the orthogonal integration of holographic and fluorescent information. This work establishes a correlation between molecular polarizability density and macroscopic holographic performance, and provides a versatile strategy for multifunctional anticounterfeiting plastics with high optical performance and mechanical robustness.