Effect of surface modification on frictional properties of polyester fabric

Characterization of frictional characteristics of textile fabrics is difficult because of surface heterogeneity in both topography and the surface chemical character, nevertheless important for tactile sensing and aesthetic appearance. Here we have addressed this problem by carrying out systematic sliding experiments on different fabrics and analyzing the data in terms of two new parameters. In particular, we have used two different types of polyester fabric which have been subjected to different surface treatments. Aqueous dispersions of hydrophobic metal-soap particles and long-chain cationic surfactant were used to modify their respective surfaces to desired extent. By sliding a soft elastomeric indenter against these fabrics over a large range of normal load, we have obtained the corresponding shear load and friction coefficient. Owing to the undulating topography of the fabric surface, both these parameters exhibit random fluctuation, so that describing such surfaces with a constant friction coefficient does not appear practical. Instead, we show that the surfaces can be characterized by the distribution of friction coefficient and the amplitude of the dominant mode of the fluctuations. These two parameters not only distinguish between different fabrics and differently treated fabrics but also quantify the extent of the treatment.