Knitting and weaving artificial muscles

TLDR

A need exists for artificial muscles that are silent, soft, and compliant, with performance characteristics similar to those of skeletal muscle, enabling natural interaction of assistive devices with humans. The study demonstrates the feasibility of wearable, soft artificial muscles made by weaving and knitting electroactive polymers, offering tunable force and strain. The authors fabricated textile actuators by coating cellulose yarns with conducting polymers, assembling them in parallel through weaving to boost force, and knitting them into stretchable fabrics to amplify strain. The actuators exhibited a linear increase in force with yarn count, a 53‑fold strain amplification in knitted fabrics, enhanced mechanical stability, and scalable production for assistive device design.

Abstract

A need exists for artificial muscles that are silent, soft, and compliant, with performance characteristics similar to those of skeletal muscle, enabling natural interaction of assistive devices with humans. By combining one of humankind's oldest technologies, textile processing, with electroactive polymers, we demonstrate here the feasibility of wearable, soft artificial muscles made by weaving and knitting, with tunable force and strain. These textile actuators were produced from cellulose yarns assembled into fabrics and coated with conducting polymers using a metal-free deposition. To increase the output force, we assembled yarns in parallel by weaving. The force scaled linearly with the number of yarns in the woven fabric. To amplify the strain, we knitted a stretchable fabric, exhibiting a 53-fold increase in strain. In addition, the textile construction added mechanical stability to the actuators. Textile processing permits scalable and rational production of wearable artificial muscles, and enables novel ways to design assistive devices.