Textile-Only Capacitive Sensors for Facile Fabric Integration without Compromise of Wearability

Wearable sensors promise advances in monitoring for athletes and patients, and offer the possibility of convenient longitudinal data collection without compromising lifestyle or comfort. To fully realize these possibilities, devices should be easily integrated into the clothing, accessories, and medical products that best suit consumers. An effective capacitive strain sensor whose components consist solely of fibers with a textile thread-like morphology, i.e., that requires no solid polymer matrix that complicates integration, and can be woven directly into the fabric of clothing, bandages, and other products is presented. It is produced by twisting two core-spun yarns into a fine double-ply yarn. The core-spun yarns are fabricated by wrapping silver-coated nylon fibers with cotton fibers, and fixing them with polyurethane. Excellent capacitive linearity is displayed, with high dielectric stability over 10 000 cycles of endurance testing. Other detection properties are in line with existing sensors, though with lower ultimate strain and elastic limit. Textile integration is demonstrated via incorporation with kneepads and gloves without compromise of comfort or range of motion. All materials are compatible with medical sterilization methods. Additional versatility is illustrated by weaving the core-spun yarn into pressure sensor arrays, which can be blended into wearable fabrics.