Fluorine-free, self-healing, and superhydrophobic coating for efficient oil/water separation and fog-water collection

Abstract

Superhydrophobic coatings have been used to solve the problems of oil spills polluting water sources and water resource shortages. However, the short service life of superhydrophobic coatings limit their widely application. In this work, a novel fluorine-free, self-healing, and superhydrophobic coating composing of polydimethylsiloxane (PDMS), polydopamine (PDA) modified halloysite nanotubes (HNT), and beeswax (BW) are fabricated for oil/water separation as well as fog-water collection. Herein, PDA stabilizes the dispersion of HNT in the coating, and meanwhile enhances the adhesion of modified nanoparticles on fabric surfaces. The as-fabricated coatings occupied a water contact angle of 163.1°, demonstrating exceptional superhydrophobic characteristics. The superhydrophobic coating exhibited superior oil/water separation efficiency of over 99.5% and outstanding fog-water collection rate of 990 ~ 1208 mg cm−2 h−1. Owing to the presence of BW, the coatings demonstrated remarkable self-healing properties and can regain superhydrophobicity after 100 wear cycles with just a short heating treatment. Therefore, this facile strategy has great potential for large-scale manufacturing of multifunctional superhydrophobic coatings.