Multifunctional Hard Yet Flexible Coatings Fabricated Using a Universal Step-by-Step Strategy.

Hard yet flexible coatings with multi-functionalities are useful for foldable displays and marine industries but rare. In this study, a highly cross-linked multifunctional hybrid coating with ceramic-like hardness and polymer-like flexibility is reported. The coating is prepared via a step-by-step strategy, where two types of epoxy-oligosiloxane nanoclusters are first synthesized by sol-gel chemistry, and amine-terminated curing agents are used to cross-link them at room temperature. The coating is highly transparent (>92% transmittance), hard (6-7H), and flexible (10 mm bending diameter) because of the unique combination of siloxane nanoclusters and polymer networks. Meanwhile, since the coating contains fouling-resistant telomer and low-surface-tension liquid lubricant polydimethylsiloxane (PDMS), it exhibits excellent anti-biofouling and self-cleaning properties. The results indicate that the mechanical and antifouling properties of the coating can be easily tuned and prove that the step-by-step strategy is a promising and universal method. The novel coatings can meet the needs of applications in foldable displays, marine industries, and other fields.