Changes in characteristics of silver conductive fabrics owing to perspiration and washing.

The original appearance and physical properties of smart clothing as well as the electrical properties of the conductive fabric applied, despite utilization and the management environment, need to be maintained. Previous research has only investigated the washability and functional changes of smart textiles according to the environment from the perspective of sensors and fabric material; however, they have not comprehensively considered actual usage conditions. In this study, changes in the appearance, color, chemical components, wettability, and electrical properties of silver-coated conductive knitted fabrics due to exposure to perspiration and washing were investigated based on the manufacturing methods of conductive fabrics. The conductive knitted fabric exposed to perspiration exhibited the most prominent color change, and the surface became rough and hydrophilic as AgCl and AgO were formed through a chemical reaction between perspiration and silver. In contrast, the conductivity of the fabric was enhanced by the release of Ag+ ions via perspiration. After washing, the silver layer on the surface of the conductive knitted fabric peeled off due to the interference and friction between the fabrics caused by the mechanical force generated during the cleaning process. There was no obvious chemical change, but the contact angle decreased as the nano-roughness decreased owing to the removal of silver particles. The conductivity slightly increased after washing but did not show a significant difference at 10% elongation. Finally, as the frequency of exposure to perspiration and washing increased, the silver layer coating the fiber or fabric surface peeled off and was damaged, resulting in a significant color change. Additionally, the chemical composition of the silver layer was significantly altered by perspiration and water and became hydrophilic. Surface resistance also increased linearly as the frequency of exposure to perspiration and washing increased. In terms of hand value, softness and smoothness decreased, and warmness increased after several cycles. Under all conditions, the conductive fabric with silver-coated yarn maintained a more optimized appearance and electrical properties than the silver-coated fabric according to the manufacturing method. Therefore, conductive yarn is more suitable for manufacturing conductive knitted fabrics for smart clothing in terms of durability. Additionally, specific management plans based on the actual use and environment of smart clothing using conductive knitted fabric are urgently needed.