Design, fabrication, and evaluation of embroidered textile electrodes for wearables under mechanical and washing stress

Textile electrodes are increasingly used for bio-signal detection in daily activities and can be integrated into garments through knitting, weaving, or stitching. Technical embroidery, offering precise control over stitch parameters, is widely preferred for producing high-quality electrodes. Since electrode performance depends strongly on electrical resistance, this study investigates how cyclic loading and washing affect the resistance of embroidered textile electrodes for wearable health monitoring. Two conductive threads, stainless steel and a hybrid copper-Kevlar yarn, were embroidered onto fabric substrates with different stretch properties and thread consumption levels. The electrodes were subjected to cyclic mechanical loading at 100, 300, and 500 cycles, followed by 10, 30, and 50 washing cycles, and their resistance was evaluated. Stainless steel electrodes showed a 10-50% increase in resistance after loading and washing, mainly due to thread fraying and disruption of conductive pathways. Hybrid-thread electrodes remained stable up to 100 cycles/10 washes but failed electrically after 30 washes, likely from copper filament breakage and potential corrosion during laundering. These results provide important insights into the durability challenges of embroidered electrodes and highlight the need to optimise thread selection, fabric characteristics, and embroidery design to improve the longevity and reliability of textile-based wearable sensing systems.