Preparation of Fluorine-Free and Durable Water-Repellent Textiles

The development of fluorine-free and mechanically durable water-repellent coatings for textiles remains a challenging topic for both academia and industry. In this study, we present a facile approach for the synthesis of a water-repellent emulsion by copolymerization of bis-vinyl capped siloxane and stearyl acrylate. The emulsion was applied to cotton via a simple dip-pad-cure process, achieving a durable superhydrophobic fabric. Stearyl acrylate containing long hydrocarbon chains provides high hydrophobicity. The introduction of siloxane can effectively improve the softness of the fabric and mitigate the chalk marks. Meanwhile, a cross-linker was utilized to ensure the strong attachment of water-repellent coatings on cotton surfaces. The treated cotton fabric can achieve a water contact angle exceeding 150° with a spray rating of grade 4 even with the emulsion concentration as low as 10 g/L. Further increasing the emulsion concentration to 20 g/L endows the fabric with the highest spray rating of grade 5 according to the standard of ISO 4920:2012. The water-repellent fabric maintains a high breathability in order to maximize comfort. Meanwhile, the treated fabric displays good resistance to scratches and chemicals, which can maintain hydrophobicity after 3000 friction cycles, 96 h of chemical exposure, and 24 h of ultrasonic cleaning. Furthermore, the water-repellent emulsion demonstrates compatibility with diverse substrates, including glass, paper, and synthetic textiles. We envision that this water-repellent emulsion will be a promising alternative to existing water repellents.