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

"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 °C under nitrogen. Their glass transitions were -22 to -51 °C, mostly ∼3 °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, σ ₂₅ = 2.27 × 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 °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 σ ₂₅ ∼ 3 × 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.