| AVS 63rd International Symposium & Exhibition | |
| Plasma Science and Technology | Thursday Sessions |
| Session PS2-ThM |
| Session: | Plasma Processing of Challenging Materials |
| Presenter: | Joffrey Baneton, Université Libre de Bruxelles, Belgium |
| Authors: | J. Baneton, Université Libre de Bruxelles, Belgium D. Merche, Université Libre de Bruxelles, Belgium G. Caldarella, Université de Liège, Belgium N. Job, Université de Liège, Belgium F. Reniers, Université Libre de Bruxelles, Belgium |
| Correspondent: | Click to Email |
The polymer electrolyte membrane is one of the most important components of proton exchange membrane fuel cells (PEMFC) because it transports the ions from one side of the cell to the other one while it prevents the passage of the electrons and then the offsetting of the accumulated charges at each electrode. It is also important for device structure and gas permeability considerations [1]. Over the years, several methods have been developed to replace conventional techniques that involve many steps and the use of solvents and expensive reagents. Some studies exhibit an interest for low-pressure plasma devices to produce sulfonated polystyrene membranes [2]. In this work, we propose an innovative approach using an atmospheric-pressure dielectric barrier discharge (DBD) with styrene as carbon matrix reagent and acid precursors (such as trifluoromethanesulfonic acid) to integrate proton exchange groups. Using this atmospheric plasma device allows to produce membranes in a ‘one-step’ process, avoiding solvents and vacuum constraints [3]. X-ray photoelectron spectroscopy (XPS) and infra-red reflection absorption spectroscopy (IRRAS) are used to determine the chemical composition of the membranes. Stylus profilometry and scanning electron microscopy (SEM) are applied to analyze their morphology. Electrochemical measurements are also performed to determine the membrane proton conductivity.
In the case of pure polystyrene films, it is shown that the plasma leads to the polymerization of the monomer without altering their chemical structure. Moreover, the optimization of the reactor geometry and the experimental variables such as the flow rate, the injected discharge power, the precursor temperature or the duty cycle (in the case of pulsed plasma) can lead to the formation of homogeneous and uncontaminated films. In the case of copolymerized membranes using an acid precursor, a high content of fragmented and distributed proton exchange groups can be observed on the XPS and IRRAS spectra.
This work was financially supported by the Walloon Region (HYLIFE project n°1410135, Energinsere program) and by the Belgian Federal Government (Interuniversity Attraction Belgian Science Policy IAP research project P7/34 – Physical Chemistry of plasma surface interactions).
[1] J. Larminie and A. Dicks. Fuel Cell Systems Explained (Second Edition), John Wiley & Sons Ltd, UK, 2003, 67–72.
[2] S. Roualdes et al. Jounal of Power Sources, 158 (2006), 1270–1281.
[3] D. Merche et al. Plasma Processes and Polymers, 7 (2010), 836–845.