Bio‐Inspired Multifunctional Superhydrophilic Coatings With Remarkably Fast Self‐Healing Abilities

Abstract

To enhance the durability of bio‐inspired superwetting coatings for real‐world practical applications, it is necessary to endow them with the methods of reasonable self‐healing abilities found in living organisms. Herein, we have successfully developed hydrogel‐based multifunctional superhydrophilic coatings, which mimic the multifunctionality of the fish body surface, and exhibit remarkably fast and repeatable self‐healing abilities. The aqueous precursor solutions, including poly(vinylpyrrolidone), nano‐clay particles, and a waterborne aminosilane, with and without metal‐ions were prepared by a two‐step integral blend method, followed by spin‐ or spray‐coating onto flat/large‐scale and 3D‐shaped glass substrates. The resulting coatings (approximately 470–720 nm in thickness) were all smooth, highly transparent, superhydrophilic [contact angle ( θ S ) of water: < 5°] in air and superoleophobic ( θ S of diiodomethane: > 170°) in water. Despite their submicron thickness, the coatings maintained anti‐fogging performance for over 6 months under high relative humidity exceeding 80%. X‐ray photoelectron spectroscopy and Fourier transform infrared spectroscopy confirmed that the addition of multivalent metal‐ions promoted hydrated ion cluster formation, thereby enhancing water absorption and self‐healing kinetics. The damaged area (approximately 20–56 µm) was completely self‐healed over nine times each within 10 s through hot steam exposure.