Atomistic insights into intermolecular formation of deep eutectic solvents and poly(acrylate) matrix and its application for the enhancing hydronium ion dynamics in proton-exchange membranes of fuel cells

Abstract

This study presents a comprehensive analysis of the intermolecular interactions and diffusion behavior in deep eutectic solvent (DES)-supported poly(acrylate) (PAA) systems, with a focus on enhancing hydronium (H₃O⁺) ion mobility for proton-exchange membranes (PEMs) in fuel cells. Using classical all-atom molecular dynamics (MD) simulations, we investigated the interactions within pure DES-supported PAA and hydrated DES-supported PAA matrices at hydration levels (HLs) 3 and 9. Radial distribution functions (RDFs) revealed significant interactions between the oxygen atoms of PAA and hydrogen atoms of DES components, with distinct variations at different HLs. Interaction energy calculations highlighted the evolving strengths of PAA-DES interactions, especially with choline, chloride, and urea, under varying hydration conditions. Diffusion coefficients indicated substantial enhancements in the mobility of H₃O⁺ ions and water molecules with increasing hydration, essential for effective proton transport. These findings underscore the critical role of water in facilitating dynamic restructuring and efficient proton conduction within the DES-supported PAA matrix, offering valuable insights for the development of advanced PEMs with tailored properties for fuel cell applications.