Conductivity and Methanol Permeability of Nafion–Zirconium Phosphate Composite Membranes Containing High Aspect Ratio Filler Particles

Abstract

Gels of exfoliated α‐zirconium phosphate (ZrPexf) in dimethylformamide (DMF) were used to prepare Nafion/ZrPexf composite membranes with filler loadings up to 7 wt.‐% by casting mixtures of Nafion 1100 solutions in DMF and suitable amounts of 2 wt.‐% ZrP gels in DMF. TEM pictures showed that the ZrPexf particles had aspect ratio of at least 20. All samples were characterised by methanol permeability (P) and through‐plane (σthp) and in‐plane (σinp) conductivity measurements at 40 °C and 100% RH. The methanol permeability of Nafion membranes containing in situ grown ZrP particles with low aspect ratio (Nafion/ZrPisg) was also determined. The methanol permeability and the swelling behaviour of the composite membranes turned out to be strongly dependent on the filler morphology. As a general trend, both permeability and swelling decreased according to the sequence: Nafion/ZrPisg > Nafion > Nafion/ZrPexf. The maximum selectivity (σthp/P = 1.4 × 105 S cm–3 s) was found for the membrane filled with 1 wt.‐% ZrPexf: this value is seven times higher than that of Nafion. For the Nafion/ZrPexf membranes, the ratio σinp/σthp increases with the filler loading, thus indicating that the preferred orientation of the ZrP sheets is parallel to the membrane surface.

Transport Properties of Zeolite Na‐X–Nafion Membranes: Effect of Zeolite Loadings and Particle Size

“…This allows the enhancement of proton conductivity at temperature above 100°C [6,7]. Furthermore, the presence of inorganic domains hinders the methanol transport allowing a lowering in the amount of methanol crossover [5].…”

“…The strategies investigated in literature to improve the performances of perfluorosulfonic polymer membranes, and Nafion in particular, show an extraordinary variety. These can be broadly divided into two approaches; either the incorporation of dispersed hygroscopic oxides [2], or the formation of hybrid membranes by in situ growth of inorganic phases [3][4][5]. …”

Fabrication and characterization of electrospun sulfonated poly(phthalazinone ether ketone) mats as potential matrix of reinforced proton exchange membranes

“…One solution is to develop novel alternative PEMs based on the sulfonated aromatic hydrocarbon polymers, such as sulfonated poly(arylene ether sulfone)s, sulfonated poly(arylene ether ketone)s, sulfonated polyimides, and sulfonated organic–inorganic hybrids . The other is to modify Nafion membrane, including the reinforcement of Nafion membrane with a supporting porous substrate, the incorporation of inorganic fillers and the forming of methanol‐blocking layer …”

Facile Preparation of α‐Zirconium Phosphate/Polyaniline Hybrid Film for Detecting Potassium Ion in a Wide Linear Range

“…Importantly, α‐ZrP as an inorganic material has an ability to recognize and exchange K + ions 12. During the last 50 years, extensive research has evolved around α‐ZrP materials which opened a wide gamut of applications, such as biosensors 13, fuel cells 14 and drug carriers 15. As far as we known, however, α‐ZrP was seldom used in preparing a sensor especially for electrochemical applications because of its poor conductivity.…”