Title of Paper:Improved conductivity and stability of anion exchange membrane modified with bi-phenylguanidinium bridged silsesquioxane

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Date of Publication:2017-08-17

Journal:INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

Included Journals:Scopus、SCIE、EI

Volume:42

Issue:33

Page Number:21016-21026

ISSN No.:0360-3199

Key Words:Biphenylguanidinium-bridged-sil-sesquioxane; Water uptake; Conductivity; Alkali stability

Abstract:This work reports the design, fabrication and properties of 4,4'-oxydiphenylguanidiniumbridged-silsesquioxane (ODGBS) modified polysulfone anion exchange membrane (AEM). It was prepared by sol-gel polymerization of ODGBS in the network of cross-linked, quaternized polysulfone. With hydrophilic biphenylguanidinium and Si-O-Si moieties working synergistically, the ODGBS derived gel functions as a water "reservoir" in the membrane and thus gives rise to high water uptake, which facilitates hydroxide ion transport via a vehicular mechanism. High water uptake may also "dilute" hydroxide ion at the vicinity of cations and lessen the hydroxide attack on cations. Moreover, ODGBS does not contain (3 hydrogen atoms, thus reducing the likelihood of Hofmann elimination under hydroxide attack. Due to the above benefits, ODGBS modified AEM could exhibit an improved conductivity from 19 to 25 mS/cm(2) at 30 degrees C, and a conductivity retention of 85% when treated in 1 M NaOH at 60 degrees C for 120 h, higher than that of the un-modified AEM (72%). This work provides a new strategy for enhancing stability and conductivity of AEM. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.