Moisture Vapor Transport Through Waterproof Breathable Fabrics and Clothing Systems Under a Temperature Gradient

Moisture vapor transport through waterproof breathable samples and clothing sys tems under a temperature gradient is examined using a simple research method. The results are compared with those obtained from isothermal tests. The transport properties are identified as being dependent on the temperature gradient across the waterproof breathable layer, the humidity of the clothing microclimate, and the interaction between water vapor and the clothing layers. The transport properties of hydrophilic polymers and clothing systems incorporating hydrophilic polymers, especially those with low transmission rates in the isothermal tests, improve by considerably greater amounts than those incorporating microporous polymers when a temperature gradient is applied.