Development of stretchable conductive hybrid yarn for wearable electronics application

Abstract

Wearable electronics and electronic textiles are becoming increasingly important as technology advances. To supply the conductivity required in wearable electronics, investigations on the integration of electronic components with textiles by adding conductivity to fabric structures, as well as the development of items generated in this manner in terms of human comfort, have grown. The base materials, i.e., yarns, should be as flexible, thin, and light as possible during the manufacturing and incorporation of electronic textile components (sensors, transmission lines, connections, etc.) into wearable products in order to tolerate the rigid structure and low elasticity of the metallic parts that provide conductivity. In traditional yarn production processes, hybrid yarn production is regularly carried out with numerous modifications. Problems arise in these manufacturing processes due to the fact that the core fiber cannot be precisely positioned in the center of the yarn, the fluctuation of yarn strength throughout the yarn, and the increase in yarn irregularity. The "Direct-Twist - 2C" twisting machine, which can manufacture hybrid-yarn without modification, was employed in this investigation. Unlike previous approaches, hybrid-yarn manufacturing with Direct-Twist aims to overcome the problems found in other ways since the core can be positioned exactly in the center of the yarn. A new hybrid-yarn was generated in this work by employing spandex in the core and silver-plated conductive yarn in the coating. Tensile and resistance measurements performed within the scope of the study demonstrate that a stretchable conductive hybrid-yarn structure with a homogeneous distribution of core and coating structures is achieved.