Water-Triggered Self-Healing Coatings of Hydrogen-Bonded Complexes for High Binding Affinity and Antioxidative Property

Recent years have witnessed the rapid developments of self-healing coatings because they can protect materials from diverse risks and are able to autonomously heal after being physically damaged. Here, a universal yet facile method is reported with high time and cost efficiency to fabricate transparent water-enabled self-healing coatings on various substrates by precipitating hydrogen-bonded tannic acid (TA)-polyethylene glycol (PEG) complexes in aqueous solution. The precipitated complexes coalesce to form uniform and transparent coatings on the substrates; after drying, mechanically robust coatings are obtained. TA endows such coatings with strong adhesion to a wide range of substrates and admirable antioxidant properties. Repeatable self-healing of the coatings is realized by simply exposing them to water or humid environment. Furthermore, these coatings can be readily erased by soaking them in basic solution, if needed.