Recent developments in artificial spider silk and functional gel fibers

It is highly desirable to develop fiber materials with high strength and toughness while increasing fiber strength always results in a decrease in toughness.Spider silk is a natural fiber material with an excellent combination of high strength and toughness,which is produced from the spinning dope solution by gelation and drawing spinning process.This encourages people to prepare artificial fibers by mimicking the material,structure,and spinning of natural spider silk.In this review,we first summarized the preparation of artificial spider silk prepared via such a gelation process from different types of materials,including nonrecombinant proteins,recombinant proteins,polypeptides,synthetic polymers,and polymer nanocomposites.In addition,different spinning approaches for spinning artificial spider silk are also summarized.In the third section,some novel application scenarios of the artificial spider silk were summarized,such as artificial muscles,sensing,and smart fibers.

Spider Silk Supercontraction‑Inspired Cotton‑Hydrogel Self‑Adapting Textiles

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,selfadaptive 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.