Bioinspired Multilayer Silicone Composites: Autonomous Healing and Rate-Dependent Mechanics via Dynamic Boron...

Inspired by the cutaneous wound healing mechanism observed in human scab formation, we engineered a series of multilayered silicone rubber composites through alternating polydimethylsiloxane (PDMS) and polydiborosiloxane (PDBS) laminates. The dynamic diboron-oxygen coordination bonds within PDBS enabled both autonomous self-healing through bond reconfiguration and enhanced impact resistance via energy dissipation. PDMS served dual functions as both a structural reinforcement matrix and a flow-restricting framework for PDBS, thereby improving the viscoelastic creep behavior and irreversible deformation tendencies characteristic of conventional non-Newtonian fluids. Notably, increasing the laminate count from 3 to 9 layers enhanced structural integration, yielding improvement in dimensional stability. All multilayer configurations demonstrated remarkable healing performance, achieving post-24 h self-healing efficiencies exceeding 95% across 3-layer, 5-layer, and 9-layer specimens. Rheological characterization revealed pronounced strain rate sensitivity under multiaxial loading conditions, with storage modulus showing proportional enhancement to applied strain rates in both transverse and longitudinal orientations.