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

Abstract

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.

Open coating with natural wax particles enables scalable, non-toxic hydrophobation of cellulose-based textiles

“…The use of silicon compounds (such as silanes and siloxanes) is often suggested as a more environmentally friendly option, even though some of them might be toxic and harmful for the environment (Hogue, 2018;Hong et al, 2014). There are various silicon compounds and application methods reported (Chen, Chen, Zhang, Yin, & Zhou, 2016;Cheng, Zhao, Weng, Li, & Zeng, 2019;Hou et al, 2018;Lahiri, Zhang, Zhang, & Liu, 2019), all with their own advantages and disadvantages. Covalent binding or adsorption of inorganic materials furthermore affect the biodegradability of cellulose, contributing to textile waste.…”

Self‐Healing Superhydrophobic Surfaces: Healing Principles and Applications

“…were able to prepare a robust fluorine‐free and self‐healing superhydrophobic coating. [ 19 ] The coated surface demonstrated excellent water repellency, with a 5 µL water droplet deposited on it presented a large CA of 158° and a small sliding hysteresis angle of 4°. Modification of PDMS endowed the surface improved durability and self‐healing property.…”

Regenerative Superhydrophobic Paper Coatings by In Situ Formation of Waxy Nanostructures

“…[ 48 ] Only few investigations focus on regenerating such a micro‐/ nanotopographic structure after it has been destroyed. [ 48,52,58–61 ] According to the above definitions, such regenerative coatings belong to the class of nonautomatic self‐healing materials, and may also be referred to as “stimulus responsive materials.” Such materials that are capable to in situ form effective nanostructures as well as possess the capability to regenerate such structures by an external trigger, are of great interest. [ 48 ] Note, only those materials and regeneration processes which are compatible with existing coating technologies, in which the recyclability of a paper material is not impaired and in which ecologically questionable substances such as organic fluorine compounds are avoided, may have good chances to be considered for furture paper applications.…”