Improved artificial spider silk created
The fibers, which resemble miniature bungee cords as they can absorb large amounts of energy, are sustainable, non-toxic and can be made at room temperature.
This new method not only improves upon earlier methods of making synthetic spider silk, since it does not require high energy procedures or extensive use of harmful solvents, but it could substantially improve methods of making synthetic fibers of all kinds, since other types of synthetic fibers also rely on high-energy, toxic methods.
The fibers are pulled from the hydrogel, forming long, extremely thin threads - a few millionths of a meter in diameter. After roughly 30 seconds, the water evaporates, leaving a fiber which is both strong and stretchy.
"Although our fibers are not as strong as the strongest spider silks, they can support stresses in the range of 100 to 150 megapascals, which is similar to other synthetic and natural silks," said Shah. "However, our fibers are non-toxic and far less energy-intensive to make."
Author Affiliations
Significance
Fiber materials have great impact on our daily lives, with their use ranging from textiles to functional reinforcements in composites. Although the manufacturing process of manmade fibers is potentially limited by extensive energy consumption, spiders can readily spin silk fibers at room temperature. Here, we report a class of material that is based on a self-assembled hydrogel constructed with dynamic host-guest cross-links between functional polymers. Supramolecular fibers can be drawn from this hydrogel at room temperature. The supramolecular fiber exhibits better tensile and damping properties than conventional regenerated fibers, such as viscose, artificial silks, and hair. Our approach offers a sustainable alternative to current fiber manufacturing strategies.
Abstract
Inspired by biological systems, we report a supramolecular polymer-colloidal hydrogel (SPCH) composed of 98 wt % water that can be readily drawn into uniform (a1/46-I1/4m thick) "supramolecular fibers" at room temperature. Functionalized polymer-grafted silica nanoparticles, a semicrystalline hydroxyethyl cellulose derivative, and cucurbit[8]uril undergo aqueous self-assembly at multiple length scales to form the SPCH facilitated by host-guest interactions at the molecular level and nanofibril formation at colloidal-length scale. The fibers exhibit a unique combination of stiffness and high damping capacity (60-70%), the latter exceeding that of even biological silks and cellulose-based viscose rayon. The remarkable damping performance of the hierarchically structured fibers is proposed to arise from the complex combination and interactions of "hard" and "soft" phases within the SPCH and its constituents. SPCH represents a class of hybrid supramolecular composites, opening a window into fiber technology through low-energy manufacturing.
