Studies of Ion Conductance in Polymers Derived from Norbornene Imidazolium Salts Containing Ethyleneoxy Moieties

초록

"Two-armed" imidazolium polymers 2a-2f, most of which contain oxyethylene moieties as linkers and ethyleneoxy terminal units, were prepared via ROMP. These polymers were thermally stable, with 5% weight losses occurring at 350 +/- 5 degrees C under nitrogen. Their glass transitions were -22 to -51 degrees C, mostly similar to 3 degrees C higher than those of the respective monomers. The conductivities of the polymers were 4-30-fold lower than those of the respective monomers. The maximum room temperature (RT) conductivity, sigma(25) = 2.27 x 10(-5) S/cm, was observed with the polymer 2f with a tetra(oxyethylene) linker (X = 4) and a terminal di(ethyleneoxy) unit (Y = 2). Reduction of the double bonds in polymers 2 resulted in only small changes in T-g of the resultant 3 but 2.4-fold loss in RT conductivities. Four "one-armed" norbornene imidazolium TFSI monomers via ROMP produced polymers 5, whose T(g)s were generally low (-50 to -65 degrees C) and very close to those of the monomers. Although the RT conductivities were reduced by about an order of magnitude from the monomers, the polymers with tetra(oxyethylene) linkers (X = 4) and di- and triethyleneoxy terminal units (Y = 2 or 3) (5c and 5d) had sigma(25) similar to 3 x 10(-5) S/cm, similar to the best two-armed polymer. Two ABA triblock copolymers 8 were successfully synthesized from norbornene-N-phenylimide and two-armed monomers with different terminal ethyleneoxy units (1d and 1e); these polymers demonstrated single direction actuation, but their performance was mediocre because of phase mixing that prevented the formation of the required bicontinuous phase morphology.

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