Reversibly interlocked networks defy the strength-stiffness-damping trade-off for adaptive structural adhesives

Structural adhesives that combine robust adhesion, low modulus, and high damping are highly desired for aerospace, automotive, and electronics applications. However, integrating these three inherently contradictory properties into a single material remains challenging due to their competing underlying mechanisms. Herein, a reversible interlocked macromolecular network (RILN) adhesive is designed through a performance-decoupling strategy: (i) a carboxyl-functionalized polyurethane (BPU) with boronic ester bonds that provides adhesion groups and dense cross-linking, ensuring strong interfacial bonding and cohesive strength; (ii) a low-modulus polyurethane (SPU) containing disulfide bonds, dangling chains, and loose cross-links that acts as an internal plasticizer to regulate modulus; and (iii) an integrated RILN structure in which extensive inter-network chain slippage enables efficient energy dissipation and high damping. The resulting adhesive exhibits high adhesion strength (9.94 MPa), low modulus (<1000 MPa), superior toughness (57.46 MJ m^-3) and consistently high damping across multiple dynamic loading modes. It also demonstrates excellent low-temperature tolerance, superior self-healing capability, detachability, and recyclability. This RILN design strategy offers a broadly applicable approach to developing adaptive structural adhesives that reconcile multiple competing properties for advanced engineering applications.