Friction Dynamics of Denim Fabrics with Washing or Polishing Treatment

The friction properties between human skin and fabrics are important because they affect the latter’s attractiveness. In this study, we evaluated the friction force on three denim fabrics and cashmere, wool, and cotton fabrics using a sinusoidal motion friction evaluation system that replicates human motion. We analyzed the effects of physical properties (elastic modulus, surface roughness, and thickness) on friction properties. Washing treatment for starch removal reduced the Young’s modulus from 36.6 ± 3.8 kPa to 16.1 ± 0.3 kPa and increased the friction coefficient from 0.28 ± 0.01 to 0.30 ± 0.01. After the fabric was polished, the Young’s modulus decreased to 8.3 ± 1.0 kPa and the friction coefficient increased to 0.33 ± 0.01. The friction coefficients of the denim, cashmere, wool, and cotton fabrics increased as their Young’s modulus decreased. Therefore, washing and polishing treatments soften denim, increase the true contact area between the contact probe and the fibers, and increase friction resistance. These findings are useful for controlling tactile textures and developing more attractive denim fabrics.