Indexed by:Journal Article

Date of Publication:2021-02-02

Journal:INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

Volume:45

Issue:35

Page Number:17893-17901

ISSN:0360-3199

Key Words:Phase separation; Self-organization; Polyelectrolyte; Molecular dynamics; Proton exchange membrane

Abstract:Low weight molecules induced self-organization behavior was proposed to tune nanophase separation morphology of sulfonated nonfluoroniated aromatic polymer membrane for improving proton conductivity. Sulfonated poly (ether ether ketone) (SPEEK) was selected as the model polymer here. Hydrophobic tetrachloroethylene (C2Cl4), amphiphilic circular molecule 3,4-dimethylbenzaldehyde (DMBA) and amphiphilic linear alcohols were adopted to induce the self-organization of SPEEK membranes. The self-organization mechanism was investigated by combined experimental and molecular dynamic simulation for the first time. Induced by hydrogen bonding and hydrophobic interaction, the amphiphilic inducers improved both proton conductivity and mechanical properties of SPEEK membranes. Moreover, owing to the effects of multiple hydrogen bonds and linear molecular structure, amphiphilic linear alcohols increased the proton conductivity more significantly than amphiphilic circular molecule DMBA. Among several linear alcohols, the molecular length of n-BuOH (5.0 angstrom) perfectly matched the distance between hydrogen of the sulfonic acid group and the benzene ring of SPEEK, resulting in the highest proton conductivity. The study provides significant guidance for exploring proton exchange membranes with well-connected proton conductive channel and high proton conductivity. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.