Natural-silk-inspired design provides ultra-tough biobased structural adhesives with supercold tolerance

Abstract

Tough adhesives with exceptional mechanical and adhesion properties under extreme conditions are essential for real application scenarios with extended service life. Nevertheless, these demands are rarely satisfied in most traditional polymeric adhesives, but spider silks have an unparalleled combination of toughness and adhesiveness at ultralow temperatures. Inspired by the spidroin's hierarchical structure and β-sheet nanocrystallites, a super-tough yet supercold-tolerant supramolecular adhesive is reported by incorporating spider-silk-like hierarchical hydrogen-bonding (H-bonding) networks and dynamic nanosized physical cross-links into biobased polyamide elastomers. Such a structural design performs its own functions and the conflict among interfacial adhesion capacity, ductility, and low-temperature resistance can be thus overcome. The obtained adhesive possesses a reliable and long-term adhesion performance while maintaining a record-high toughness of 4052.4 N m⁻¹ with favorable rebonding capability even in liquid nitrogen (−196 °C), far exceeding the adhesive toughness of reported polymeric adhesives in such environments. Moreover, high-density H-bonding-induced emission of the amide cluster leads to a strong blue fluorescence in the solid-like elastomer. This concept creates a new opportunity for designing tough elastic adhesives and offers promise for cold-resistant adhesive devices or anti-counterfeiting displays.