Self-Healable, Considerably Stretchable, and Wide-Temperature-Range-Damping Waterborne Polyurethane Elastomers by Constructing the Spider-Silk-Like Structures

Waterborne polyurethane (WPU) has garnered considerable attention, owing to its environmentally friendly characteristics and diverse application potentials. However, its limited mechanical strength and toughness restrict its practical applications in demanding long-term loading scenarios. Herein, we propose a biomimetic microstructure strategy to address these limitations by preparing tannic acid-functionalized boron nitride nanosheets (TA@BNNSs) through π-π stacking interactions, thereby structurally substituting the β-sheet nanocrystals in spider silk. Upon incorporation into WPU via solution processing, robust interfacial hydrogen bonds are formed between TA@BNNSs and WPU, establishing a hierarchical architecture that mimics the β-sheet/amorphous matrix organization of natural spider silk. This bioinspired microstructure facilitates effective stress distribution and energy absorption, resulting in elastomers with exceptional mechanical characteristics, such as an ultrahigh toughness (660 MJ m-3, which is about 4 and 24 times higher than those of spider silk and pure WPU, respectively), high tensile strength (37.4 MPa), and considerable stretchability (3433%). Additionally, the remarkable self-healing efficiency (75-100%) and broad damping temperature range (>100 °C) can further extend the elastomers' service life in harsh environments. This study not only advances the design of high-performance elastomers through biomimetic microstructure strategy but also demonstrates their potential for critical applications in advanced damping systems and wearable technologies.