Robust and Multifunctional Wetting Resistance of de novo Engineered Nonfluorinated Metal–Organic Nanocrystals for Environmental Sustainability

Direct synthesis of zeolitic imidazole framework crystals using bulky alkyl ligands is challenging. Herein, a bottom‐up approach to de novo synthesis of a superhydrophobic zeolitic metal–organic framework called mZIF, using mixed ligands, is developed. The mZIF nanocrystals contain a newly designed alkyl chain‐substituted 4‐imidazolate ligand, achieving tailorable hydrophobicity by varying the alkyl tail length. The molecular structure presenting appropriate ligands coupled with the porosity and roughness of the coated surfaces imparts superhydrophobic properties to various coated surfaces such as glass, steel, aluminum, and plastic. The resulting surfaces exhibit a high contact angle of ≥157° and a minimal rolling‐off angle (<5°), enabling efficient oil–water separation in a filtration setup. Furthermore, dip coating the mZIF nanocrystals onto a melamine sponge modifies its water wettability, allowing for facile and efficient removal and recovery of oil from diverse oil–water mixtures with exceptional reusability. Additionally, the mZIF‐modified surfaces showcase notable self‐cleaning and anti‐icing properties. The mZIF‐coated surface shows remarkable storage stability (>1 year), durability against harsh environmental conditions, and notable resistance to mechanical abrasion. This research represents a significant advancement in the facile engineering of multifunctional metal–organic framework‐based systems tailored for diverse practical applications.