Interfacial Kinetic Control Enables Regulated Growth of Functional Metal–Phenolic Network Films

Abstract Metal–phenolic network (MPN) films are of widespread interest because of their potential application in biotechnology, catalysis, and the environment. Their formation typically involves the supramolecular assembly of phenolic ligands and metal ions from solution onto a solid substrate. Such assembly has been conducted exclusively from a single-phase solution, thus limiting spatiotemporal control over coordination and/or the range of precursors that can be used, and thereby restricting the compositional and structural diversity, as well as functionality, of MPN films. Herein, we report a liquid–liquid interfacial assembly (LLIA) approach, which leverages two immiscible phases, to prepare functional MPN films with specific properties. LLIA enables both the kinetic regulation of film growth (a key parameter in designing films with desired properties) and the use of a broader range of building blocks. The assembled MPN films exhibit controlled thickness (∼30–500 nm) and stiffness (∼2–12 GPa) and distinct structural properties (e.g., crystallinity) relative to other methods, which contribute to their conductivity and molecular selectivity (e.g., H2/CO2 separation performance). Functional MPN films with wettability, conductivity, antibacterial, or fluorescence properties are assembled by integrating various functional components (e.g., polymers, nanoparticles, and dyes), as well as inorganic and metal–organic framework films.