Electrical and mechanical properties of conductive elastic bands as wearable sensors

Crochet-based elastic textiles represent a promising option for wearable sensors due to their good stretchability and flexible structure. However, achieving cyclic electrical stability under realistic physiological motion and mechanical wear remains a critical challenge. This study systematically investigates the mechanical, aesthetic, and electrical performance of crochet elastic bands integrated with silver-coated polyamide (Ag/nylon) conductive yarns for wearable sensing applications. Dynamic resistance measurements were conducted using a custom-designed breathing simulator that replicates human respiratory motion, enabling real-time evaluation under cyclic deformation conditions. Conductive yarns were incorporated at different structural positions within the elastic bands to examine the influence of yarn configuration on sensor durability and signal stability. To simulate the cyclic use, samples were subjected to controlled abrasion cycles of 0, 5000, and 10,000 cycles. The results demonstrate that increasing abrasion levels lead to a gradual reduction in tensile strength and elongation due to progressive changes in surface morphology and stitch regularity, resulting in modified electrical pathways with the formation of pilling. Electrical performance strongly depended on conductive yarn placement. While several configurations exhibited significant signal degradation or delayed failure under abrasion, a specific configuration featuring balanced warp-weft integration of conductive yarns showed exceptional electrical stability, maintaining nearly constant resistance response across all abrasion levels. Statistical analysis confirmed the significant effects of both yarn configuration and abrasion cycles (p < 0.05). These findings highlight the critical role of conductive yarn positioning in enhancing the durability and sensing reliability of crochet-based wearable sensors. The proposed design strategy provides valuable guidance for the development of robust wearable sensors capable of maintaining stable electrical performance under simulated physiological motion and cyclic mechanical abrasion.