Preparation of superhydrophobic and UV blocking cotton fabric via sol–gel method and self-assembly

Superhydrophobic surface has been successfully prepared on cotton substrates with inexpensive and ordinary raw materials, Al(NO3)3 and sodium stearate (C17H35COONa). Such surfaces were obtained first by dip-coating the nano-Al sol, then the surface of the Al coating was modified with sodium stearate, to gain a thin film through self-assembly. The wettability of treated fabrics was characterized by water contact angle, spray test and hydrostatic pressure test. The results showed that the cotton fabrics treated with 1.5% Al sol and 20 mmol/L sodium stearate showed excellent hydrophobic properties and UV protection efficiency, water contact angle could reach 146.27° and the UPF value was 164.06 (UPF rating 50+). The morphology and surface roughness were characterized by SEM and AFM. The interaction between sodium stearate and Al coating was elucidated by XPS.