Biomimetic Supramolecular Fibers Exhibit Water‐Induced Supercontraction

• Published in: Advanced materials (Weinheim) Vol. 30; no. 27; pp. e1707169 - n/a
• Main Authors: Wu, Yuchao, Shah, Darshil U., Wang, Baoyuan, Liu, Ji, Ren, Xiaohe, Ramage, Michael H., Scherman, Oren A.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.07.2018
• Subjects: biomimetic; Biomimetic materials; Damping capacity; Elasticity; Humidity; Materials science; Mechanical properties; Muscles; Proteins; Scanning electron microscopy; Silk; Spiders; supercontraction; supramolecular fibers; Synthetic fibers; supramolecular fibers; supercontraction; biomimetic
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201707169

Spider silk is a fascinating material, combining high strength and elasticity that outperforms most synthetic fibers. Another intriguing feature of spider silk is its ability to “supercontract,” shrinking up to 50% when exposed to water. This is likely on account of the entropy‐driven recoiling of secondary structured proteins when water penetrates the spider silk. In contrast, humidity‐driven contraction in synthetic fibers is difficult to achieve. Here, inspired by the spider silk model, a supercontractile fiber (SCF), which contracts up to 50% of its original length at high humidity, comparable to spider silk, is reported. The fiber exhibits up to 300% uptake of water by volume, confirmed via environmental scanning electron microscopy. Interestingly, the SCF exhibits tunable mechanical properties by varying humidity, which is reflected by the prolonged failure strain and the reversible damping capacity. This smart supramolecular fiber material provides a new opportunity of fabricating biomimetic muscle for diverse applications. A spider‐silk‐inspired supramolecular fiber, spun from a hydrogel (98 wt% water) at room‐temperature, is reported, which exhibits water‐induced supercontraction of up to 50%, tunability in mechanical properties with humidity, and high damping capacity of 75%.