Proton conductivity in sub-micron thick ion-conducting polymer (ionomer) films at the electrode-catalyst interface is crucial for electrochemical devices but is often limited by substrate-induced confinement. To address this challenge, we employed epoxy ring opening chemistry in combination with macrocyclic cavitand molecules with ion-conducting groups to engineer the electrode interface. These molecules mimic biological ion channels, forming robust and more precise ion-conduction pathways that can alleviate interfacial ion transport limitations effectively. The layer by layer (LBL) assembly process utilizes a pH-triggered epoxy ring-opening reaction, enabling precise control over film growth and promoting favorable ionomer orientation. Characterization techniques including X-ray photoelectron spectroscopy (XPS), profilometry, and atomic force microscopy (AFM) confirm successful film formation. Preliminary findings reveal that this LBL architecture enhances proton conductivity by nearly an order of magnitude compared to Nafion, particularly across a range of humidity conditions. This approach demonstrates the potential of tailored interfacial engineering to optimize proton transport, contributing to the advancement of next-generation electrochemical technologies. This project was funded by the U.S. Department of Energy (DOE) Office of Science through Early Career Award.
