Biomimetic discontinuous Bouligand structural design enables high-performance nanocomposites

Abstract

<h2>Summary</h2> Bouligand structures across several species invariably hold the mechanical foundation for the survival of living organisms. Transcribing them into synthetic analogues will promote the development of structural materials. Although superior nanofibers emerge continuously, arranging them into structurally and mechanically optimized biomimetic assemblies remains challenging. Here, we propose a programmable assembly strategy and construct discontinuous Bouligand structural nanocomposites with eco-friendly, silicon-based nanofibers and biopolymer. Unique helicoidal organization and discontinuity enable the resultant nanocomposites' synergetic toughening via crack twisting and fiber bridging. The optimal nanocomposite exhibits superior tensile strength (356.1 MPa), energy absorption (28.8 MJ m⁻³), and fatigue durability (more than 30,000 bending cycles), outperforming many natural and synthetic Bouligand structural analogues. They hold potential as sustainable materials for mechanical protection or tissue engineering. The discontinuous Bouligand structural design proposed here, combining the programmable nanofiber assembly strategies, will drive innovation of traditional continuous macrofiber-reinforced plastics and help creation of advanced nanofibrous composites.