DYNAMIC WATER-VAPOR AND HEAT-TRANSPORT THROUGH LAYERED FABRICS .1. EFFECT OF SURFACE MODIFICATION

An experimental apparatus has been developed to permit simultaneous measurement of temperature change and moisture flux through fabrics during the transient period after one set of fabrics has been exposed to humidity and temperature gradients. Both the water vapor method and the sweat method were used to study the transport of water vapor and water vapor emanating from liquid water in contact with the bottom layer of fabric through several fabrics. Tested fabrics included single fiber and blended fiber fabrics, treated either by hydrophobically or hydrophilically. Analysis of the experimental results verified that after either hydrophobic or hydrophilic treatment, the fabrics did not show any significant change in moisture flux when compared to their untreated counterparts using the water vapor method, but did show a significant difference when measured by the sweat method. In the sweat case, the dominant factor that controls the water vapor transfer rate is considered to be the wicking ability of the fabric.