Superhydrophobic fabric mixed with polyester and cotton yarns modified by alkaline treatment and thermal aging

Superhydrophobic fabric composed of polyester and cotton single yarns was developed by alkali treatment and thermal aging. During the alkali treatment to make the nano-roughness of the polyester fibers, micro-roughness also increased due to differences in the thicknesses of the two yarns arising from the increased polyester surface roughness and swollen cotton. The superhydrophobicity, with a static contact angle of 155.8 ± 3.2° and shedding angle of 11.1 ± 0.8°, was achieved with 90% polyester/10% cotton fabric treated with 20% alkali concentration for 20 min under applied tension, then followed by 24 h thermal aging at 130℃. The tensile strength of the superhydrophobic polyester/cotton fabric (28.7 MPa) was higher than that of 100% polyester fabric (20.1 MPa). The breathability of the superhydrophobic polyester/cotton fabric was improved compared with 100% polyester fabric. In durability assessment, a static contact angle of ≥150° was shown for the tape tests. Five times of repeated adhesion with a clothing tape cleaner were conducted for the five samples each. Although washing and dry-cleaning decreased contact angles to as low as 137.7°, a static contact angle of 150° was achieved by additional thermal aging (130℃, 24 h). We developed a superhydrophobic fabric mixed with polyester and cotton yarns by exploiting differences in the characteristics of the two yarns induced by alkali treatment, which causes fabric surface roughness, and thermal aging without the use of any chemicals. Moreover, this superhydrophobic fabric has improved breathability.