Electrothermal and Mechanical Characterization of Stainless Steel and Silver-Coated Cabled Yarns for Heating Application

The development of conductive fibers and yarns is growing exponentially due to their utilization in wearable electronic textiles for heating, sensing, and energy storage applications. Herein, we report the electrothermal and mechanical properties of stainless steel (SS) and silver-coated (SC) cabled yarn for application in knitted wearable heating pads. SC yarn offers superior heating performance over SS yarn due to its low resistance, but its long-term durability, washability, and thermal stability are lower than SS yarn. The SS yarn is thermally stable up to 70 °C with minimal resistance change. However, the resistance of SC yarn increased by 81.12%, and the average temperature was reduced by 23.23% due to the oxidation of silver in an open environment after exposure for 50 days. The localized heating pad was designed using SC and SS cabled yarn. The temperature of the SC-based pad was 37.5 °C, while the temperature of the SS-based pad was 34.3 °C at a 9 V DC power supply. However, the variation between the maximum and minimum surface temperatures is considerable in the case of an SC-based heating pad.