Intelligent safeguarding Leather with excellent energy absorption via the toughness-flexibility coupling designation

Highlight • Designing a novel toughness and flexibility coupling structure for next-generation soft body armor. • Combining biocompatible materials (leather) with raterelated material (shear stiffening gel) to fabricate the Leather/CNT-SSG/PU. • Novel Leather/CNT-SSG/PU coupling structure possesses high impact energy absorption, high limit ballistic penetration velocity, and special stress wave dissipation ability. • Constructing an intelligent bulletproof vest with excellent anti-impact performance and in situ monitoring behavior. High-performance intelligent body armors with both soft wearability and good energy absorption are increasingly required in modern social life. Leather, a breathable, pliable, and tough natural material has extensive applications in the anti-impact field. In this study, a multifunctional Leather/CNT-SSG/PU sandwich structure with high energy absorption and excellent sensing monitoring properties is designed by integrating tough leather and flexible conductive shear stiffening gel (CNT-SSG). The maximum force dissipation capacity of the Leather/CNT-SSG/PU reaches 84 % in the drop hammer test and the limit penetration velocity up to 142.4 m/s in the ballistic test. Moreover, the Leather/CNT-SSG/PU exhibits excellent stress wave dissipation properties due to the hierarchical structure. By introducing the interdigital electrode array on the non-woven fabric layer, a bulletproof vest (Leather/CNT-SSG/NWF) with intelligent anti-impact performance and in situ monitoring behavior is successfully achieved. This toughness and flexibility coupling designation provides a novel method for next-generation soft body armor.