| 초록 |
In PEMFCs, ionomers are used in the catalyst layer to increase the interfacial area between the electrode and the electrolyte, and the microstructure of the ionomer affects the performance of the fuel cell. In this study, the effect of pKa of dispersion solvent on the microstructure of protonated phosphonic acid ionomer (PWN) was analyzed. Protonated phosphonic acid ionomer was prepared by 1:1 blending of PFSA and PWN66 with phosphonic acid using various dispersion solvent with different pKa values. With a large pKa solvent, phosphonic acid well-accommodated the protons of sulfonic acid, increasing miscibility of PFSA and PWN66, and thus exhibiting a transparent and dense structure. On the other hand, with a small pKa solvent, the miscibility is reduced, resulting in an opaque appearance and a microporous structure. Therefore, it was possible to control the microporous structure of protonated phosphonic acid ionomers by adjusting the pKa of the ionomer dispersion solvent. |
