Evaluation of conductive threads and stitch configurations for heated e-textile applications

Electrically heated textiles (EHTs) utilise Joule heating to provide warmth and comfort across a range of applications, including medical, military, and industrial settings. EHTs can be manufactured using conductive threads, inks, and coatings—either individually or in combination. In this study, a method of manufacturing EHTs based on printing and stitching techniques to achieve large-area heating elements was devised. This study explores the selection of appropriate conductive threads and assesses the performance of lockstitch and chainstitch configurations for creating robust electrodes in EHTs. A variety of commercially available conductive threads were evaluated for durability, electrical performance, and functional integrity when used in various stitching configurations. Although surface-coated conductive threads offered effective electrical conductivity, their durability was notably reduced following exposure to washing and abrasion. The findings further indicate that lockstitch configurations deliver superior performance compared to chainstitch, due to the resulting lower linear resistance of the stitched electrode. Employing conductive threads in the bobbin position proved more effective in maintaining thread integrity. The study also examined the effect of increased stitch density on the structural integrity of functional ink layers, revealing potential negative impacts on heating functionality. Overall, this research offers valuable insights into material selection and manufacturing techniques, supporting the development of more reliable and scalable EHT products.