Self-Healing Properties of Fibers Constructed from Mushroom-Derived Chitinous Polymers

Chitinous polymers were extracted from common Agaricus bisporus mushrooms through simple processes, which are successfully formed into continuous fibers with a custom-built laboratory-scale fiber spinning setup. The spun fibers are composed of numerous chitin fibrils embedded within the glucan matrix, and their fiber diameters are controlled by the needle gauges. All the mushroom chitin fibers exhibited self-healing properties upon exposure to a small amount (<10 μL) of water within 30 s. The macroscopically damaged mushroom chitin fibers with a microblade can repair their original shape and tensile properties effectively, as evidenced by high self-healing efficiency for the tensile strength (up to 119%) and breaking strain (up to 132%). Interestingly, no solvents, such as ethanol or acetone, other than water induced the self-healing. This indicates that swelling and deswelling of mushroom chitin fibers may have led to the intermeshing of chitin fibrils and glucan across the damaged fiber interfaces, resulting in powerful self-healing action. Simple preparation of chitin fibers provides sustainable manufacturing opportunities for real-world applications in various technical areas, as we demonstrated the repeatable self-healing performance on a large scale in the form of fibers and woven structures.