Proton conduction in 1H‐1,2,3‐triazole polymers: Imidazole‐like or pyrazole‐like?

Abstract

Proton transport (PT) plays an important role in many biological processes as well as in materials for renewable energy devices. Gaining insights into functional group requirements for PT would aid the design of new materials that provide enhanced proton conduction. In this report, we outline our efforts to understand the most probable proton conduction pathway in 1H-1,2,3-triazole systems. In triazole-based systems, both imidazole-and pyrazole-like pathways are possible. By systematically comparing structurally analogous polymers based on Nheterocycles and benz-N-heterocycles, we find that the imida-zole-like pathway makes a significant contribution to the proton transfer in 1H-1,2,3-triazole systems, while the contribution from pyrazole-like pathway is negligible.

Novel polyelectrolytes containing perfluorocyclobutane and triazole units: synthesis, characterization and properties

“…A maximum conductivity of 2.85 mS cm À1 was obtained at 200 1C under anhydrous conditions. The proton conductivities of polymer 8 were lower than the values previously reported, 16,17 which could be attributed to the higher T g and lower triazole content of polymer 8. The introduction of more than one triazole per repeat unit did not result in an increase in conductivity because there was an accompanying increase in T g ; 16 thus, two methods are suggested to improve the proton conductivity.…”

“…These polymers were stable up to B290 1C, which is much higher than that of previously reported polymers. 16,17 Proton conductivity. The proton conductivity of polymer 8 was measured from 40 to 200 1C under anhydrous conditions using impedance spectroscopy.…”

“…Proton conductivity of the polymers was measured using a previously published method. 17 Synthesis of monomers (6) Preparation of 1,3-bis(2-bromotetrafluoroethoxy)anisole (1). A mixture of 5-methoxyresorcinol (14.0 g, 0.100 mol), 1,2-dibromotetrafluoroethane (77.7 g, 0.300 mol) and Cs 2 CO 3 (97.8 g, 0.300 mol) in dry DMSO (250 ml) was stirred for 3 days at 50 1C.…”

“…Recently, nitrogencontaining heterocyclic compounds, such as imidazole, pyrazole and benzimidazole, have been suggested as proton solvents for proton exchange membrane fuel cells, and they may also be covalently tethered to some suitable polymers to prepare fully polymeric materials. [9][10][11][12][13][14][15][16][17][18] Liu et al 19 suggested that 1H-1,2,3-triazole has adequate electrochemical stability for fuel cell applications, and the 1H-1,2,3-triazole groups immobilized on a polymer backbone may open up new avenues in the design of polyelectrolytes. To date, several polymeric systems with tethered 1H-1,2,3-triazole moieties have been evaluated as polyelectrolytes.…”

“…To date, several polymeric systems with tethered 1H-1,2,3-triazole moieties have been evaluated as polyelectrolytes. [13][14][15][16][17] However, most of these polymers derived from polyacrylate or polyethylene may have issues related to their electrochemical or dimensional stability for medium temperature fuel cells. During the past decade, partially fluorinated polymers containing perfluorocyclobutane (PFCB) rings have been developed.…”