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Preparation and proton conductivity of poly( N ‐methylbenzimidazole) doped with acid
Author(s) -
Pu Hongting,
Liu Gaihua
Publication year - 2004
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.527
Subject(s) - conductivity , proton , doping , solubility , materials science , proton transport , arrhenius equation , membrane , moiety , chemistry , stereochemistry , activation energy , physics , biochemistry , optoelectronics , quantum mechanics
To increase the solubility and film forming ability of polybenzimidazole (PBI), poly( N ‐methylbenzimidazole) (PNMBI) with different degrees of methylation was synthesized. Chemical structure, degree of substitution, and solubility of PNMBI was studied. PNMBI is easier to be doped with acid than PBI. The basicity of PNMBI was improved with the introduction of methyl groups on the imidazole moiety. Effects of methylation degree, H 3 PO 4 content and temperature on proton conductivity of PNMBI doped H 3 PO 4 was studied. Proton conductivity of H 3 PO 4 doped PNMBI‐1.2 membranes increases with increasing doping level. Temperature dependence of proton conductivity of H 3 PO 4 doped PNMBI‐1.2 membranes follows the Arrhenius law. With an increase in the degree of substitution, proton conductivity of H 3 PO 4 doped PNMBI decreases dramatically. The proton transport mechanism was also discussed. The proton conductivity of PNMBI/H 3 PO 4 is mainly contributed by proton hopping or Grotthuss mechanism. Copyright © 2004 John Wiley & Sons, Ltd.