Improvement of the Water Absorbency of Softener-treated Fabric: Addition of a New Hydrophilic Surface.

Abstract

Softening agents, when applied in appropriate amounts, can impart softness to fabrics, particularly cotton towels, such that improved comfort and feel can be achieved when using the fabrics. On the other hand, water absorbency, which is commonly regarded as the mark of high-quality cotton products, significantly decreases when any of the currently existing softeners is used. To date, when a softener is used on cotton fabrics, there is a trade-off between excellent softness and high-water absorbency. In our research, we introduced a new sensory evaluation indicator called the "water wiping-off feeling ratio" which looks primitive but shows high correlation with our actual feel over any other existing indicators. Furthermore, we developed a new method and model to overcome the above-mentioned trade-off, involving the use of small particles with a hydrophilic surface together with the softener. Inspired by the theory of fractal geometry and the combination of models/equations by Cassie, Baxter, and Wenzel, the idea of adding new convex hydrophilic domains onto the surface of cotton fibers along with the softening agent was conceived. Finally, we successfully improved the wiping-off feel without decreasing the softness, i.e., we developed a strategy to overcome the above-mentioned trade-off in softener-treated fabrics that has proven challenging thus far.