Study of the wicking behavior of stretched elastic yarns under finite liquid droplets

Abstract

The liquid water transport performance of fabrics is a critical factor in maintaining thermal and moisture comfort for the human body. Subjected to various dynamic stresses, elastic sportswear exhibits a relatively complex structure. However, most existing studies on the wicking behavior of elastic yarns are conducted under infinite liquid supply conditions, which do not realistically reflect the finite perspiration conditions of the human body. Furthermore, there is a lack of systematic investigations into the wicking behavior of single yarns, plied yarns, and interlaced structures under varying stretching states. In this study, an experimental platform was developed to simulate human perspiration in the form of microdroplets, and the wicking performance of polyester elastic filaments, piled yarns, and plain-woven interlaced networks under various stretching states was systematically investigated. The results indicated that stretching reduced both the yarn diameter and average hydraulic diameter. Moderate stretching improved the wicking length of both single and plied yarns, although a peak value was observed. Increases in twist level and stretch both reduced the initial wicking rate of plied yarns, while a higher number of plies mitigated the negative effects of high twist and stretching. The wicking length of plied yarns was generally greater than that of single yarns, and a significant positive correlation was observed between them. Moreover, the Lucas–Washburn equation demonstrated strong applicability for predicting the initial wicking behavior (1 s) under finite droplet conditions, although its applicability range of average hydraulic diameter depended on droplet volume. Simulations using Ansys software also showed strong agreement with experimental results. A significant negative correlation was observed between wicking length (120 s) and average hydraulic diameter. In the woven network, liquid preferentially diffused rapidly along yarns under lower stretch and then penetrated from the interlacing points into yarns under higher stretch. As the stretch difference between warp and weft yarns increased, the transfer of liquid from highly stretched yarns to those with lower stretch was significantly reduced. Additionally, the wicking lengths of the warp and weft yarns were strongly correlated with the wicking lengths of their corresponding plied yarns. This study systematically elucidated the mechanisms by which stretching influences the wicking performance of polyester elastic yarns under finite droplet conditions. The wicking behaviors of single yarns, piled yarns and woven networks under various stretch states were correlated, thus advancing theoretical understanding of liquid transport at the yarn level in elastic sports textiles. In addition, a preliminary simulation method for yarn wicking behavior was developed, providing both experimental evidence and theoretical support to facilitate the development of yarn-network-based capillary models for predicting liquid transport performance in fabrics. These findings offer valuable insights for the structural optimization and functional design of high-performance elastic sportswear.