Rapid fabrication of stretchable, ultratough, and rigid polymer materials.

Polymer materials hold great promise for various applications but face trade-offs among stiffness, toughness, stretchability, and scalable fabrication. Here, we report a strategy that integrates dense side-chain hydrogen-bonding motifs capable of conformational transitions into a highly entangled flexible polymer network through photocuring copolymerization of acrylamide-based and hydroxyl-terminated acrylate monomers, enabling the rapid fabrication of stiff, tough, and stretchable polymers. The densely cross-linked structure restricts chain mobility, while hierarchical hydrogen bonds with partially low rotational energy barriers reversibly dissociate under strain, allowing the extensibility of the entangled network and continuous energy dissipation. The resulting polymers exhibit high Young's modulus (515.0 ± 100.9 megapascals) and yield strength (57.8 ± 1.8 megapascals) while maintaining exceptional toughness (135.7 ± 10.7 megajoules per cubic meter) and fracture strain (400.1 ± 46.1%) and full strain recovery upon heating. These polymers can be fabricated into complex structures via three-dimensional printing and exhibit shape-memory, impact-resistant, and adhesive properties. This work establishes a generalizable strategy for designing high-performance polymer materials through simple photopolymerization.