Nafion-Initiated ATRP of 1-Vinylimidazole for Preparation of Proton Exchange Membranes

Abstract

Nafion is one of the most widely investigated materials applied in proton exchange membranes. Interestingly, it was found that Nafion could serve as a macroinitiator to induce atom transfer radical polymerization (ATRP) on its C-F sites. In this study, poly(1-vinylimidazole) was selectively bonded on the side chains of Nafion via the Nafion-initiated ATRP process, which was confirmed by the measurements of (1)H/(19)F nuclear magnetic resonance spectra, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, differential scanning calorimeter and matrix-assisted laser desorption ionization-time-of-flight/time-of-flight mass spectrometry. The as-prepared Nafion-co-poly(1-vinylimidazole) (Nafion-PVIm) membranes, with tunable loading amount of imidazole rings, presented greatly enhanced proton conductivity and methanol resistivity due to their well-controlled chemical structures. Especially, chemically bonding PVIm with Nafion chains endowed the Nafion-PVIm membranes with high stability in proton conductivity. For the first time, we revealed the great potentials of the Nafion-initiated ATRP process in developing high-performance proton exchange membranes.

Tetra-alkylsulfonate functionalized poly(aryl ether) membranes with nanosized hydrophilic channels for efficient proton conduction

“…Nafion ® (DuPont), as the state-of-the-art PEM, has excellent stability under acidic and oxidative conditions and outstanding proton conductivity at relatively low ion exchange capacities (IECs) [8,9] . However, it suffers from several shortcomings such as high fuel/gas diffusion, reduced mechanical property at elevated temperatures, poor recyclability, and significant manufacturing costs [10,11] . To explore alternative PEMs, worldwide researchers have focused on several sulfonated hydrocarbon polymers [12] , including sulfonated poly(aryl ether)s [13] , polyphosphazene [14] , polyimides [15] , poly(phenylene)s [16] , polystyrenes [17] , polybenzimidazoles [18] , etc.…”

Proton conductivity study on three CS/IL@fle‐MOF membranes

“…Besides, the large‐scale practical application of Nafion is hampered by its relatively low thermal stability, dangerous manufacturing processes, and high costs. [ 11–16 ] Therefore, it is of great practical significance to create new proton conducting materials to extend the temperature range of PEM, to reduce the production cost, and to increase the proton conductivity.…”

Sulfonated graphene oxide‐doped proton conductive membranes based on polymer blends of highly sulfonated poly(ether ether ketone) and sulfonated polybenzimidazole

“…However, they still suffer from several drawbacks such as high cost, low thermal stability, high gas permeability, low relative selectivity, and significant decrease of proton conductivity at high temperature and low humidity conditions due to membrane dehydration, which would impede its use at large‐scale and commercial applications. To overcome these shortcomings, there has been a considerable effort to develop new high‐performance proton conductive membranes from alternative materials including sulfonated poly(ether ether ketone) (s‐PEEK) …”