Researchers create strong 'super silk' that maintains shape after wetting

Researchers create strong 'super silk' that maintains shape after wetting Lisa Lock Scientific Editor Andrew Zinin Chief Editor Painstakingly woven from the cocoons of silkworms, silk has been valued for more than 4,000 years as a luxury material. More than just beautiful, silk is also lightweight, strong and biocompatible, allowing it to be used for clothing, medical materials and more. However, conventional silk has a glaring weakness—it shrinks and loses its shape after repeated exposure to moisture. Researchers at Tohoku University have developed high-performance silk that largely solves this weakness. Instead of tampering with the silk fibers, the research team targeted an earlier step in the process by altering the diet of silkworms. The result is silk fibers with 50% greater tensile strength and reduced shrinkage after wetting and drying to less than one-quarter that of untreated silk. These improvements were seen even when the silk fibers were processed into yarn and woven fabrics, meaning that we may be on the right path to using this "super silk" effectively in final products. The findings are published in the Journal of Industrial Textiles. These improvements were achieved by adding plant-derived cellulose nanofibers (CNFs) to silkworm feed. Other methods may require toxic chemical treatments or extensive changes to the silk production process. In contrast, simply adding a sprinkle of sturdy CNF to silkworm feed represents a practical and environmentally friendly way to produce higher-value silk products. "Silk is not just for fashion—it is also used in a plethora of different industries you might not initially think of," explains Associate Professor Hiroki Kurita (Tohoku University). "For example, silk can be used in a medical setting as surgical sutures or a biomaterial to promote wound healing." Based on their previous work, the researchers expected the new diet to strengthen individual silk fibers but were unsure whether these benefits would persist after spinning and weaving or whether they could improve dimensional stability under wet conditions. These findings suggest that small changes during silk production can have a large impact on the performance of finished textile products. "Our goal was to improve silk while preserving its natural advantages. We were excited to find that simply changing the silkworms' diet produced silk that is both stronger and much more dimensionally stable in wet environments. We hope this sustainable approach will contribute to the development of next-generation functional textiles," says Kurita. More information Camille Moreau et al, Tensile properties and dimensional stability of cellulose nanofiber-reinforced silk fabrics by silkworm feeding, Journal of Industrial Textiles (2026). DOI: 10.1177/15280837261463657 Provided by Tohoku University