Proton mobility in oligomer-bound proton solvents: imidazole immobilization via flexible spacers

A completely new approach for obtaining high proton conductivity in polymer s based on proton solvating heterocycles covalently bound via flexible spac ers is presented. Imidazole-terminated ethyleneoxide (EO) oligomers as mode l materials have been characterized with respect to their conductivity by a c impedance spectroscopy and with respect to H-1- and F-19-diffusion coeffi cients by pulsed magnetic field gradient-NMR (PFG-NMR). Comparison of condu ctivity and NMR diffusion coefficients of pure and acid doped materials sho ws 'structure diffusion' (intermolecular proton transfer and structural reo rganization by hydrogen bond breaking and forming processes) to be the domi nant conduction process, which gives rise to proton conductivities of up to 5 X 10(-3) S cm(-1) at 120 degreesC in completely waterfree materials. (C) 2001 Elsevier Science B.V. All rights reserved.