Robust Fluorine-Free and Self-Healing Superhydrophobic Coatings by H3BO3 Incorporation with SiO2–Alkyl-Silane@PDMS on Cotton Fabric

Limited robustness is a serious drawback for superhydrophobic coatings and degrades the performance of superhydrophobic surfaces in practical applications. Although fluororeagents have excellent durability for superhydrophobicity, their use has been restricted due to various health and environmental concerns. In this work, we describe a facile and efficient fabrication strategy for creating robust fluorine-free superhydrophobic composite coatings that are prepared by a simple dip-dry method, in which the H3BO3-incorporated SiO2–alkyl-silane coatings are deposited on woven cotton fabric surfaces followed by polydimethylsiloxane modification. The coated surface shows a large water contact angle of 157.95 ± 2° and a small sliding hysteresis angle (SHA) of 3.8 ± 0.6°, demonstrating excellent superhydrophobicity. The coated fabric surface also exhibited robustness and durability, withstanding a tape-peeling test (under 48.05 kPa) for around 80 repetitions and sandpaper rubbing (loaded 100 g) for 40 cycles. Furthermore, the coated fabric surface displayed self-healing and oil–water separation capacities. The developed superhydrophobic coatings in this study are robust, environmentally benign, and easy to fabricate, showing promising applications in textile industries.