Fiber Hygroscopicity and Perceptions of Dampness

A series of dampness perception trials has determined the influence of fiber type, fabric moisture content, and ambient conditions on the subjective assessment of dampness in fabrics. Twenty subjects evaluated four fabrics of different fiber types ( wool, cotton, polyester, and a wool / polyester blend) at five levels of moisture content at 25°C and three levels of relative humidity (25, 50, and 75%). The trials revealed that dampness perception and fiber hygroscopicity were interrelated. Wool, which is highly hygroscopic, was perceived to be significantly drier than weakly hygroscopic polyester at 25% relative humidity. The differences in dampness perception became smaller as the ambient humidity increased, and also as the moisture content of the fabrics increased.