Dynamic Moisture Vapor Transfer through Textiles

Cotton, polyester, and a blend in plain woven, pure finish fabrics were studied to determine their influence on dynamic surface wetness and moisture transfer through textiles. A simulated sweating skin was used, over which were placed test fabrics incorporating a clothing hygrometer to continuously measure dynamic surface wetness. Moisture vapor concentration and its rate of change at both inner and outer fabric surfaces was determined. At the inner fabric surface facing the sweating skin, all-cotton fabric exhibited the slowest buildup of moisture vapor concentration, followed by the cotton/polyester blend. The all-polyester fabric showed the highest rate of change in moisture vapor concentration. These dynamic moisture changes differ from reports of little or no fiber effect when tested at equilibrium moisture transfer conditions. Indeed the equilibrium moisture vapor transfer also showed no significant fiber differences in this work. It is the short time, dynamic moisture vapor transfer that is believed to hold most promise for explaining wetness and moisture-related subjective sensations in human comfort of worn clothing. The newly modified clothing hygrometer provides a sensitive method for ascertaining dynamic surface wetness on both fabrics and clothing as worn.