The effect of the heat transfer mechanism on the psychophysical assessment of moisture sensation in fabrics

Perceived moisture in fabrics is a crucial factor affecting wearing comfort. The aim of the current study was to investigate the effect of the conductive, evaporative and mechanical cues on moisture sensation. Thirteen participants assessed fabric wetness perception in both hot and neutral environments, and the difference threshold and the sensory magnitude of moisture were determined. Three types of knitted fabric were covered with or without an impermeable polyvinyl chloride (PVC) film and were used to simulate either the water evaporation or not. The results showed that the influence of conduction on moisture sensitivity was greater than that of evaporation, as proved by the 0.1 units of increase in the Webber fraction by conduction, compared with only 0.03 units of increase by evaporation. In addition, the relationship between the moisture sensation and the stimulus intensity demonstrated a psychophysical power function. The exponents of the power functions were found to be between 0.15 and 0.45, depending on the stimulus conditions, and the cold-wet stimulus triggered significantly greater moisture sensation than the warm-wet stimulus. Fabrics restrained from evaporation by PVC film resulted in a greater moisture sensation as the supplied water was held as free liquid, which either increased cooling cues in the cold-wet stimulus or increased mechanical cues in the warm-wet stimulus. The results suggest that factors such as clothing fitness, fabric property and environmental conditions might interactively affect human moisture sensation, and future researches are necessary to understand how these initial results would relate to an overall garment.