Evaluation of the possibility of using surface free energy study to design protective fabrics

Contact angle measurements, using the dynamic contact angle and Washburn methods, were taken for 100% aramid and viscose fabrics, as well as for 50:50 aramid and viscose mixed fabrics of different structure. Based on the measurements of contact angles wetted with hexane, water and formamide, the fabric surface free energy was calculated by means of three (Owens–Wendt, Wu and van Oss–Chaudhury–Good) theoretical models. The aim of the study was to analyze the usefulness of the dynamic contact angle and Washburn methods for assessing surface properties of textile materials, using selected measurement liquids, and to relate the results to the further investigation of actual wetting and penetration of model fabrics designed to protect against hazardous or irritant liquids. It was found that both methods are useful for determining the fabric surface free energy values; the Washburn method is characterized by the high practical value in assessing surface properties of textile materials, regardless of their structure, whereas the dynamic contact angle method allows for more thorough observation of how the fabric structure of the same raw material composition exerts its effect on the wettability and surface free energy value.