Structural design and physical characteristics of modified ring-spun yarns intended for e-textiles: A comparative study

E-textiles based on yarn-based sensors have been a topic of intense research. In our previous paper, a straightforward way for fabricating tri-component elastic-conductive composite yarns (t-ECCYs) with a unique architecture applicable to yarn-based sensors was proposed using a modified ring-spinning frame. Herein, a comparative analysis of the physical characteristics of t-ECCY, bi-component elastic composite yarn (b-ECY), bi-component conductive composite yarn (b-CCY), and single rayon yarn (s-RY) are presented, in detail, in terms of tensile behavior, elastic recovery, electrical resistance, unevenness, and hairiness. In particular, a systematic study of the tensile and conductive properties of yarns appropriate for e-textiles, that is, t-ECCY and b-CCY, are highlighted. In addition, a non-invasive structure verification technique is conducted to identify the dispositions of constituents inside the yarn. It is found that the t-ECCY exhibits a remarkable improvement over the other yarns, having robust tensile properties, super elasticity, stable electrical durability, lower unevenness, and hairiness. A simple tensile model has been proposed to predict the t-ECCY’s tensile strength, and the substantial improvement in the tensile properties of t-ECCY compared with the b-CCY can be associated with the distinctive yarn structure. The stretch-deformation mechanism of coils in the t-ECCY is, initially, separation of adjacent surfaces of coils and gradual unwinding till free. Benefiting from its superior conductivity and elasticity after single/cyclic stretch tests as well as other properties, the t-ECCY itself can serve as a sensing element, which could be a highly valuable use for specific purposes in smart textiles.