Developing high-performance bio-based fibres is highly desirable for improving the sustainability of materials. Cellulose is one of the most abundant bio-derived feedstocks to fabricate such materials. However, the fabrication of high-strength macro cellulose fibres is challenging due to the difficulty in obtaining ordered packing of cellulose molecular chains and nanocrystals in the macro-fibres. Here we develop a draw spinning/de-acetylation method to prepare cellulose fibres with highly ordered molecular packing that incorporates high strength in the obtained fibres. Specifically, a fibre draw spun from well-dispersed cellulose triacetate solution was de-acetylated to generate cellulose fibres, which were then twisted to spirally align the molecular chains. The resulting fibres exhibited mechanical strength of 3.08 GPa and toughness of 215.1 MJ m-3, much higher than existing fibre materials. This work paves the way to obtaining high-performance bio-based fibres.

The development of functional surgical sutures with excellent mechanical properties, good fluorescence, and high cytocompatibility is highly required in the field of medical surgeries. Achieving fibers that simultaneously exhibit high mechanical robustness, good spinnability, and durable fluorescence emission has remained challenging up to now. Taking inspiration from the spinning process of spider silk and the luminescence mechanism of jellyfish, this work reports a luminous artificial spider silk prepared with the aim of balancing the fiber spinnability and mechanical robustness. This is realized by employing highly hydrated segments with aggregation-induced luminescence for enhancing the fiber spinnability and polyhydroxyl segments for increasing the fiber mechanical robustness. Twist insertion during fiber spinning improves the fiber strength, toughness, and fluorescence emission. Furthermore, coating the fiber with an additional polymer layer results in a "sheath-core" architecture with improved mechanical properties and capacity to withstand water. This work provides a new design strategy for performing luminescent and robust surgical sutures.

AbstractSpider silk exhibits an excellent combination of high strength and toughness, which originates from the hierarchical self-assembled structure of spidroin during fiber spinning. In this work, superfine nanofibrils are established in polyelectrolyte artificial spider silk by optimizing the flexibility of polymer chains, which exhibits combination of breaking strength and toughness ranging from 1.83 GPa and 238 MJ m−3 to 0.53 GPa and 700 MJ m−3, respectively. This is achieved by introducing ions to control the dissociation of polymer chains and evaporation-induced self-assembly under external stress. In addition, the artificial spider silk possesses thermally-driven supercontraction ability. This work provides inspiration for the design of high-performance fiber materials.

自然界中存在多种捻曲结构,研究发现该捻曲结构有助于改善物质的性能,进而实现丰富的生物学功能.研究人员通过模仿天然捻曲结构对高分子纤维进行加捻,开发了适用于多种应用场景的捻曲纤维.纤维在加捻的过程中会产生捻矩,内部结构呈现螺旋取向,同时分子链排列也会更加紧密.这种内部结构的变化使纤维在机械性能、热效应和电力学等方面增加了一些特性.因此,基于这些特性可以将捻曲纤维应用于多个领域的发展中.本文介绍了捻曲纤维的制备原理,综述了捻曲纤维在人工肌肉、制冷和发电等应用中的最新进展,并对捻曲纤维的发展前景进行了展望.

The axial orientation of molecular chains always results in an increase in fiber strength and a decrease in toughness. Here, taking inspiration from the skin structure, artificial spider silk with a buckled sheath–core structure is developed, with mechanical strength and toughness reaching 1.61 GPa and 466 MJ m −3 , respectively, exceeding those of Caerostris darwini silk. The buckled structure is achieved by nano‐pulley combing of polyrotaxane hydrogel fibers through cyclic stretch–release training, which exhibits axial alignment of the polymer chains in the fiber core and buckling in the fiber sheath. The artificial spider silk also exhibits excellent supercontraction behavior, achieving a work capacity of 1.89 kJ kg −1 , and an actuation stroke of 82%. This work provides a new strategy for designing high‐performance and intelligent fiber materials.

Spider dragline silk is draw-spun from soluble, β-sheet-crosslinked spidroin in aqueous solution. This spider silk has an excellent combination of strength and toughness, which originates from the hierarchical structure containing β-sheet crosslinking points, spiral nanoassemblies, a rigid sheath, and a soft core. Inspired by the spidroin structure and spider spinning process, a soluble and crosslinked nanogel is prepared and crosslinked fibers are drew spun with spider-silk-like hierarchical structures containing cross-links, aligned nanoassemblies, and sheath-core structures. Introducing nucleation seeds in the nanogel solution, and applying prestretch and a spiral architecture in the nanogel fiber, further tunes the alignment and assembly of the polymer chains, and enhances the breaking strength (1.27 GPa) and toughness (383 MJ m-3 ) to approach those of the best dragline silk. Theoretical modeling provides understanding for the dependence of the fiber's spinning capacity on the nanogel size. This work provides a new strategy for the direct spinning of tough fiber materials.

This paper develops an actuator by mimicking the makeup application process and achieves jumping under moisture stimuli and directional controlled jumping with an asymmetric structural design under NIR light inspired by frog jumping.

Smart textiles are able to self-adapt to an irregular surface. So, they found new applications in intelligent clothes and equipments, where the properties and functionality of traditional polymeric fibers are insufficient, and hard to be realized. Inspired by the supercontraction behavior of the spider silk, we prepared a spinnable hydrogel to form a sheath-core-like composite yarn, after being coated on cotton yarn. The strong hydrogen bonding between the cotton yarn and the polar groups of the hydrogel provides an outstanding mechanical stability, and the twists insertion forms a spiral-like architecture, which exhibited moisture-responsive super contraction behavior. By structural tailoring the chirality of the fiber twists and coiling extends into homo-chiral and heterochiral architectures, as displays contraction and expansion when is exposed to the moisture. Once the relative humidity is increased from 60 to 90%, a homochiral yarn exhibits 90% contraction, while a heterochiral yarn shows 450% expansion, and the maximum work capacity reached up to 6.1 J/Kg. The super contracted yarn can be re-stretched to its original length manifesting cyclability, which can be exploited to build a smart textile, self-adaptive to irregular surfaces. Such a strategy may be further extended to a wide variety of materials to achieve intelligent textiles from common fiber or yarns.

蜘蛛丝因其优异的力学性能和良好的生物相容性,一直吸引着科学家的研究兴趣.但蜘蛛在大规模繁殖中互相残杀的特性导致其无法像蚕丝一样实现商业化生产,因此,研发人造蜘蛛丝及仿蜘蛛丝纤维成为解决上述问题的有效方法.为更好地理解蜘蛛丝强韧的本质,综述了天然蜘蛛丝的结构,包括一级结构、β-折叠晶体网络(纳米纤维)结构及其形成过程.介绍了目前人造蜘蛛丝与仿蜘蛛丝纤维的制备进展,包括使用的多肽、非重组蜘蛛纤维蛋白、高分子材料和碳纳米管材料等,为下一步研究与规模化制备人造蜘蛛丝及仿蜘蛛丝纤维提供参考.