Design of fluorine-free waterborne fabric coating with robust hydrophobicity, water-resistant and breathability

Hydrophobic functionalized coatings have attracted widespread attention in fabric finishing fields, which exhibit breathable properties and can significantly enhance wearer comfort. However, the inadequate hydrophobic durability of inorganic coating and poor biologically safety of fluorine-containing coatings limited the further development of fabric finishing coating, thus it remains a significant challenge to develop fluorine-free and durable fabric finishing coating. In this study, a glyceryl monostearate (GMO)-modified fluorine-free waterborne polyurethane (WPU) emulsion (WSiPU) was synthesized and applied as a hydrophobic coating on different type of fabrics successfully. The optimal additive amount of GMO was determined by investigating the particle size and size distributions of the emulsions, solvent swell rates, wettability of water and oil on the coatings, and hydrophobicity. Cotton fabric treated with optimized WSiPU 8 emulsion exhibited excellent hydrophobicity, durability, reusability, solvent resistance, breathability, and bio-safety. Furthermore, clothing and gloves treated with WSiPU 8 emulsion exhibited excellent water repellency under flowing water and after soaking in sewage. The treated cotton fabric showed excellent hydrophobicity (water contact angle > 140°), durability (>50 resistance cycles of abrasion and laundry), and self-cleaning performance. The findings of this study provided novel insights for various applications such as oil–water separation and hydrophobic coatings.