Studies on thermal comfort of multi-layered fabric assembly after wetting with sweat and distilled water

Textiles play a vital role in assuring the thermal stability of the human body. The absorption of perspiration or moisture from a humid environment might result in wet clothing. Protective and sports apparel are often wet when the wearer is involved in high level of activity; thereby affecting the comfort. In order to understand the comfort behaviour of textiles in wet state, most of the researchers used the distilled water or NaCl aqueous solution. However, human sweat is a very complex aqueous mixture of chemicals comprising of salts, lipids, urea, lactic acid, carbohydrates, and minerals. In the present study, the effect of simulated sweat solution on the thermal behaviour of multi-layered fabric assembly is studied and compared with that of distilled water. The multi-layered fabric assembly consists of breathable PU-coated nylon as an outer layer; polyester knitted fabric as an inner layer; and micro-polyester wadding/hollow-polyester wadding/spacer fabric as the middle layer. In addition, the inner layer (next to the skin) is also tested for thermal comfort for both dry and wet states. It is observed that thermal properties of fabrics are drastically affected under wet conditions. The inner layer of fabric wetted with distilled water shows higher thermal conductivity as compared to that wetted with simulated sweat. Among various multi-layered assemblies, the thermal resistance and thermal diffusion of multi-layered assembly having hollow polyester wadding as a middle layer is high as compared to that having spacer fabric in the middle, under both dry and wet conditions.