Functionalization of PTFE substrates with quaternary ammonium groups: An approach towards anion conducting properties
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In: Applied surface science, Vol. 661.2024, No. 15 July, 160084, 10.04.2024.
Research output: Contribution to journal › Article › Research › peer-review
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TY - JOUR
T1 - Functionalization of PTFE substrates with quaternary ammonium groups
T2 - An approach towards anion conducting properties
AU - Bandl, Christine
AU - Kern, Wolfgang
AU - Ranz, Matthias
AU - Grabner, Bianca
N1 - Publisher Copyright: © 2024 The Author(s)
PY - 2024/4/10
Y1 - 2024/4/10
N2 - Hydrogen produced by electrolysis using renewable energy sources offers a zero-emission alternative to fossil-based sources providing high efficiencies in all energy sectors. Anion Exchange Membrane Water Electrolysis (AEM-WE) combines the advantages of the established technologies, alkaline (AEL) and proton exchange membrane (PEM) water electrolysis. However, AEM-WE still requires optimization, especially with regard to the membrane, catalysts and electrode structure. In this contribution we focus on the improvement of PTFE-based binders for AEM-WE membranes, which provide high chemical stability but lack the required ion conductivity. Thus, the functionalization of PTFE towards quaternary ammonium moieties (QAS) was investigated employing two approaches: (i) NH3-plasma treatment and (ii) O2-plasma with subsequent coupling of aminosilanes. Finally, the surface coupled amino groups were converted into QAS via alkylation with iodomethane (CH3-I), introducing ion conductivity. Successful functionalization was proved by X-ray photoelectron spectroscopy (XPS), displaying changes in the surface composition of PTFE surfaces such as the introduction of amino groups at the expense of fluorine, and the increase in surface carbon content upon alkylation. Furthermore, contact angle measurements revealed increased wettability with water due to the introduction of the polar surface functionalities, while zeta potential measurements confirmed the increase of positive surface charges along the modification processes.
AB - Hydrogen produced by electrolysis using renewable energy sources offers a zero-emission alternative to fossil-based sources providing high efficiencies in all energy sectors. Anion Exchange Membrane Water Electrolysis (AEM-WE) combines the advantages of the established technologies, alkaline (AEL) and proton exchange membrane (PEM) water electrolysis. However, AEM-WE still requires optimization, especially with regard to the membrane, catalysts and electrode structure. In this contribution we focus on the improvement of PTFE-based binders for AEM-WE membranes, which provide high chemical stability but lack the required ion conductivity. Thus, the functionalization of PTFE towards quaternary ammonium moieties (QAS) was investigated employing two approaches: (i) NH3-plasma treatment and (ii) O2-plasma with subsequent coupling of aminosilanes. Finally, the surface coupled amino groups were converted into QAS via alkylation with iodomethane (CH3-I), introducing ion conductivity. Successful functionalization was proved by X-ray photoelectron spectroscopy (XPS), displaying changes in the surface composition of PTFE surfaces such as the introduction of amino groups at the expense of fluorine, and the increase in surface carbon content upon alkylation. Furthermore, contact angle measurements revealed increased wettability with water due to the introduction of the polar surface functionalities, while zeta potential measurements confirmed the increase of positive surface charges along the modification processes.
UR - http://www.scopus.com/inward/record.url?scp=85190282292&partnerID=8YFLogxK
U2 - 10.1016/j.apsusc.2024.160084
DO - 10.1016/j.apsusc.2024.160084
M3 - Article
AN - SCOPUS:85190282292
VL - 661.2024
JO - Applied surface science
JF - Applied surface science
SN - 0169-4332
IS - 15 July
M1 - 160084
ER -