Fundamentals of Moisture Transport in Textiles

Magnetic resonance imaging (MRI) and other techniques are being used to investigate moisture transport in textiles. MRI revealed that moisture distribution in carpet is significantly influenced by the details of the vacuum extraction procedure used to remove excess water. Industrially relevant through-flow drying of carpet has been simulated on a laboratory-scale dryer as well as inside an MRI scanner. While the laboratory dryer provides information on the overall drying process, the MRI scanner provides details of the drying process inside the fibrous substrate. Pore structure and diffusion of fluids within textiles has been studied with diffusion NMR. Biomimetic engineering of new fibrous materials for exceptional water repellency has been pursued by analyzing the special structure of duck feathers. A new technique for measuring anisotropic wicking of yarns has been developed. Wicking rates of PET yarns were found to decrease with increasing twist and increasing tensile force, both of which result in decreased capillary radii. MRI and light microscopy revealed that fluids are primarily carried through yarn interiors and not along surfaces. Introduction Innovative and improved manufacturing processes can only be developed if the interactions between process chemicals and textile products are understood on a fundamental level. For example, current drying processes can be made much more efficient, migration problems can be controlled, and completely new designs for drying equipment can be proposed. In addition, new materials for fluid management can only be developed by understanding fundamental interactions between fluids and fibrous assemblies.