Influence of quaternization and polymer blending modification on the mechanical stability, ionic conductivity and fuel barrier of sodium alginate-based membranes for passive DEFCs

In this present study, new Quaternized sodium alginate/polyvinyl alcohol membranes (designed as QSA/PVA) has prepared using a simple solution casting method. The introduction of quaternary ammonium functional groups grafted to SA biopolymer effectively improves ionic conductivity and fuel barrier. Besides, the SA-based membranes blended with PVA and glutaraldehyde as cross-linking agent enhanced the mechanical stability of membranes. Three-dimensional network formation between QSA, PVA and GA reduced the ethanol permeability of 1.75 10(-)(7) cm(2) s(-1) and increased the ionic conductivity by 2.21 x 10(-2) S cm(-1) at 30 degrees C. The water uptake, swelling ratio, tensile strength and elongation at break results of the QSA/PVA membranes shown the mechanical stability improvement of the SA-based membranes. Finally, the maximum power density of crosslinked QSA/PVA blend membrane is higher compared to pure SA membrane via passive direct ethanol fuel cells (DEFCs). Hence, crosslinked QSA/PVA blend membrane promising the potential as polymer electrolyte membranes in passive DEFCs. (C) 2020 Elsevier B.V. All rights reserved.