Introduce proton-conducting groups
Modify PVA using 1,3-propanesultone and sodium 3-sulfobenzoate as alternative sulfonating agents.
Education / M.Sc. Research
M.Sc. Research Project · 2011–2013
Proton-Conducting Membranes Based on Poly(Vinyl Alcohol)
Research project focused on the synthesis, optimization and characterization of non-fluorinated PVA-based membranes for polymer electrolyte membrane fuel-cell applications.
The Research Project
Development and optimization of PVA-based membrane materials.
The project investigated proton-conducting membranes based on poly(vinyl alcohol), or PVA, as a non-fluorinated polymer matrix for possible use in polymer electrolyte membrane fuel cells.
Proton-conducting functionality was introduced using two different sulfonating agents: 1,3-propanesultone and sodium 3-sulfobenzoate. The modified polymers were subsequently crosslinked using glutaraldehyde or terephthalaldehyde in order to improve their mechanical properties and stability in aqueous environments.
The work included screening of sulfonation and crosslinking routes, optimization of the crosslinking degree, comparison of membrane behavior in dry and wet conditions, and selection of the most promising formulations for electrochemical testing.
The resulting materials were characterized by ATR-FTIR, elemental analysis, water-uptake measurements, ion-exchange-capacity determination, TGA-QMS and impedance spectroscopy. Selected membranes were used to prepare membrane-electrode assemblies and were tested in a model PEM fuel cell against commercial Nafion 117.
Research Objectives
From chemical modification to fuel-cell evaluation.
Optimize membrane crosslinking
Compare glutaraldehyde and terephthalaldehyde and determine a crosslinking level that provides suitable wet-state stability.
Characterize membrane properties
Evaluate chemical composition, water uptake, ion-exchange capacity, thermal stability and proton conductivity.
Test PEMFC applicability
Prepare membrane-electrode assemblies and compare selected PVA membranes with Nafion 117 in a model PEM fuel cell.
Research Workflow
A complete experimental membrane-development workflow.
01
PVA membrane preparation
→
02
Sulfonation-route screening
→
03
Crosslinker selection and optimization
→
04
Physicochemical and electrochemical characterization
→
05
MEA preparation and PEMFC testing
Methods
Tools and research methods
Experimental Work
Work completed during the project
- Preparation of PVA films and optimization of the drying procedure.
- Comparison of glutaraldehyde and terephthalaldehyde as crosslinking agents.
- Optimization of the theoretical crosslinking degree to 50% of the available hydroxyl groups.
- Sulfonation of PVA using 1,3-propanesultone and sodium 3-sulfobenzoate.
- Evaluation of membrane behavior in dry and water-saturated conditions.
- Verification of synthesis routes by ATR-FTIR and elemental analysis.
- Determination of water uptake, ion-exchange capacity, thermal stability and proton conductivity.
- Preparation of membrane-electrode assemblies and testing in a model hydrogen-fed PEM fuel cell.
Research Results
Main findings of the experimental study.
Sulfonation route
The route based on 1,3-propanesultone successfully introduced sulfonic groups into PVA. The sodium 3-sulfobenzoate route did not produce stable sulfonation after crosslinking.
Crosslinking conditions
Terephthalaldehyde provided better mechanical properties than glutaraldehyde. A theoretical crosslinking degree of 50% was selected as the best compromise between swelling and brittleness.
Selected membrane systems
PVA-10PS-TA and PVA-15PS-TA showed the best overall balance of mechanical properties and proton-conducting behavior among the investigated formulations.
Fuel-cell validation
Both selected membranes produced reproducible polarization curves in the model PEM fuel cell, although their maximum power remained below the Nafion 117 reference.
Why It Matters
From membrane chemistry to electrochemical performance.
The project covered the complete development path of a functional membrane material: chemical modification, formulation screening, crosslinking optimization, analytical characterization and testing in an operating electrochemical cell.
It also showed the practical trade-off between sulfonation, water uptake, mechanical stability and proton conductivity. These relationships became directly relevant to my later work with membrane-electrode assemblies, catalyst-coated membranes, PEM fuel cells and PEM electrolysis.
Research Highlights
Key elements of the project.
Material screening
Experimental comparison of two sulfonating agents and two crosslinking agents for the same PVA polymer matrix.
Formulation optimization
Selection of crosslinking conditions and sulfonation levels based on wet-state mechanical behavior and analytical results.
Functional validation
Preparation of MEAs and direct comparison of the selected PVA-based membranes with commercial Nafion 117.
Conference Contributions
Workshop on Polymer Ion Exchange Membranes
Bad Zwischenahn, Germany · 2013
- Development of Proton-Conducting Polymer on Poly(Vinyl Alcohol) and Poly(Ethylene-co-Vinyl Alcohol)
- Proton Conducting Nonfluorinated Polymers Used for PEM Fuel Cell Applications
Presented with L. Lancucki, K. Kruczała and S. Schlick.
Connection to Later Work
From polymer membranes to hydrogen technologies.
The project provided direct experience with the relationship between polymer chemistry, membrane processing and electrochemical performance.
This work later became relevant to my professional activities in fuel-cell systems, PEM electrolysis, electrode manufacturing, catalyst-coated membranes and membrane-electrode assemblies.