One-Step Synthesis of Superhydrophobic Coating on Cotton Fabric by Ultrasound Irradiation

Superhydrophobic textiles are materials that have been treated to become resistant to penetration by water and wetting. Such materials have attracted substantial interest because of their high potential for applications in various areas. They are usually made in a two-step coating process: formation of nanoscale roughness on microscale fibers and subsequent hydrophobization by low-surface-energy materials. In this study, a facile one-step ultrasound-assisted approach was developed for the synthesis of silica nanoparticles (SiNPs) functionalized with octyltriethoxysilane and their in situ incorporation into cotton fabrics. The fabrics were tested in terms of water contact angle (CA) and water shedding angle (SHA) and were characterized by SEM, EDX and FTIR spectroscopies, and reflectance spectrophotometry. SEM and AFM images revealed that the functionalized SiNPs formed a nearly close-packed assembly on the fibers and increased the roughness value of the fabric. The fabric showed stable superhydrophobicity with CA and SHA values of 152.8 degrees +/- 2.6 degrees and 8 degrees, respectively. Reflectance spectra showed that the coating was transparent and could not affect the color of the fabric. In addition, the coating had high stability against repeated washing, and its mechanical properties were not substantially affected.