Nanofibril Organization in Silk Fiber as Inspiration for Ductile and Damage-Tolerant Fiber Design

Ductile and damage-tolerant fibers(DDTFs)are desired in aerospace engineering,mechanical engineering,and biomedical engineering because of their ability to prevent the catastrophic sudden structural/mechanical failure.However,in practice,design and fabrication of DDTFs remain a major challenge due to finite fiber size and limited processing techniques.In this regard,animal silks can provide inspirations.They are hierarchically structured protein fibers with an elegant trade-off of mechanical strength,extensibility and damage tolerance,making them one of the toughest materials known.In this article,we confirmed that nanofibril organization could improve the ductility and damage-tolerance of silk fibers through restricted fibril shearing,controlled slippage and cleavage.Inspired by these strategies,we further established a rational strategy to produce polyamide DDTFs by combining electrospinning and yarn-spinning techniques.The resultant polymeric DDTFs show a silk-like fracture resistance behavior,indicating potential applications in smart textile,biomedicine,and mechanical engineering.