Water Transport Mechanisms in Textile Materials

Abstract

In view of the interest in the phenomenon of "wicking" in apparel fabrics made of synthetic fibers or of blends, a basic study of the mechanism of water transport in yarns and fabrics has been made. The movement of water along fabrics is shown to depend on the laws of capillary action. Because the rates of travel of water in many fabrics and in yarns from these fabrics are approximately equal, it is concluded that water is carried mainly in the capillaries formed by the fibers in the individual yarns. The speed of travel of water in these capillaries is readily reduced by the presence of randomly arranged fibers in the yarn, and it is this factor rather than the nature of the fiber mate rial which accounts for the wide range of water transport properties found in blended fabrics. The rates at which drops of water placed on the surface of such fabrics are absorbed also appear to depend on the same principles. However, for the fabrics that have been studied, these are considerably lower in magnitude than the rates for water travel within the fabrics. Since the water-holding capacities of fabrics made of different fiber materials in a similar construction are also similar, the amount of water carried by a fabric in a rate experiment depends mainly on the capillary laws which define the distance of travel in unit time. The rate of travel of water in a group of wool-type blended fabrics can be correlated with their thermal resistance properties, and both appear to depend on the arrangement of the individual fibers in the fabrics. Random arrangement of the fibers in the yarns leads to fabrics along which water travels slowly and which possess increased thermal insulation in the moist state. The water transport properties of fabrics in general provide useful information about fiber arrangement in fabrics and yarns, and it appears that the rather simple drop absorption technique for surface wetting can be conveniently used for this purpose in studying wool-type fabrics.