Spider silk-inspired tough materials: Multi-pathway synthesis, advanced processing, and functional applications

Tough materials play an important role in human society, from daily life, and industry to military. However, the contradiction between strength and ductility limits the development of tough materials. With the development of bionics, researchers are inspired by the unique properties of spider silk. Spider silk is a natural protein fiber with ultra-high toughness and strength, and has optical, thermal, water response, and biocompatibility. The excellent mechanical properties of spider silk are associated with its unique multistage structure, including the primary and secondary structures of spider silk proteins, nanofibril, and skin-core structures. Limited by the production of natural spider silk, the researchers focused on mimicking the structure of spider silk, especially the β-fold structure, to create ultra-tough biomimetic materials. In this review the relationship between the structure and properties of natural spider silk, and the latest progress in the synthesis of tough materials from different raw materials are discussed. Various advanced spinning processing technologies are summarized, and then many advanced applications based on the unique properties of tough materials are pointed out. Based above, some progress has been made in spider silk-inspired tough materials, and this review aims to provide a complete set of guidelines to produce this fascinating material.