Synthesis and Functional Development of Metal–Phenolic Network Films

Abstract

© 2025 Tianzheng WangMetal-organic frameworks (MOFs) are of broad scientific and industrial interest due to their unique hybrid physicochemical properties arising from organic ligands and metal ions. The structural characteristics of organic ligands—whether flexible or rigid—significantly influence their coordination networks, thereby determining MOF morphologies, properties, and applications. Amorphous MOFs typically derived from flexible ligands, offer versatile substrate-coating capabilities but often exhibit limited control over morphologies, pore sizes, and thickness. In contrast, crystalline MOFs fabricated from rigid ligands possess well-defined pore structures, while their coating compatibility with diverse substrates is often restricted. This thesis focuses on precisely engineering MOF properties and functions by integrating amorphous and crystalline coordination networks, specifically by developing novel metal-phenolic networks (MPNs) consisting of metal ions and natural phenolic ligands. First, a universal approach for crystalline MOF coating is developed by utilizing amorphous MPN interfaces, enabling controlled assembly on a wide variety of particle and planar substrates for different applications (e.g., gas separation). Second, a robust and versatile method for MPN film growth via liquid-liquid interfacial assembly is introduced, accommodating both flexible and rigid phenolic ligands. The resulting interfacial assembled MPN films exhibit tunable physicochemical properties (e.g., thickness and morphology), possess microporous structures, and can be integrated with diverse functional components (e.g., polymers and nanoparticles) to achieve desired properties (e.g., wettability, conductive, and antibacterial properties). Finally, a novel class of reversible conduction switching materials based on MPN films is discovered, which leverages thermally induced crystalline coordination networks with electronic correlations. These MPN films show ultrahigh resistivity in the insulating state but relatively high Hall mobility in the conductive state, along with tunable transition temperatures and scalable production capability. Collectively, these studies provide insights into the interplay between amorphous and crystalline coordination networks, advance MPN assembly strategies, and expand their potential applications across multiple fields, including environmental science, materials science, and electronics