Regenerative Electroactive Self-Assembled Layers from Reversible Non-Covalent Interactions

Abstract

Tethering redox-active molecules to electrode surfaces bridges the atomistic control prized in homogeneous systems with the practicality of reusable heterogeneous electrodes. Synthetic strategies for immobilization are traditionally designed to be permanent and thus lack a mechanism for repairing in situ molecular detachment or degradation. A repair mechanism tuned to overcome the rates of molecular detachment and degradation would instead allow continuous regeneration of the desired electrochemical activity. Here, we develop a mechanism-guided strategy for regenerative self-assembled electroactive layers by leveraging electrostatic and van der Waals interactions as dynamic and reversible non-covalent tethers. Using ferrocene-labeled amphiphile monomers as a model system, we quantify the kinetics of molecular self-assembly, disassembly, and induced degradation under electrochemical conditions. We show that non-covalent self-assembly and disassembly dynamics at the electrode interface is tuned by synthetically varying the monomer tail length, and we identify rates that compete with molecular degradation. We assemble our kinetic data into a mechanistic model that predicts the exchange dynamics that allow intentionally degraded molecules to be replaced in situ. Our work unlocks non-covalent, reversible tethering of redox-active molecules at electrode surfaces as a molecularly tunable repair mechanism to enhance durability in electrochemical applications.