Conductive Polymer Electrolytes Derived from Poly(norbornene)s with Pendant Ionic Imidazolium Moieties

Poly(norbornene)s with pendant imidazolium moieties and three different counter anions, i.e. poly[exo,endo‐5‐norbornene‐2‐yl‐carboxyethyl‐3‐ethylimidazolium bis(trifluoromethyl‐sulfonyl)imide], poly(exo,endo‐5‐norbornene‐2‐yl‐carboxyethyl‐3‐ethylimidazolium tetrafluoroborate), and poly(exo,endo‐5‐norbornene‐2‐yl‐carboxyethyl‐3‐ethylimidazolium hexafluorophosphate) were prepared via ROMP using ionic liquids as the reaction medium. The ionic polymers possessed M w in the range 8.1–44 × 103 and ionic conductivity up to 1.13 × 10−5 and 1.44 × 10−4 S · cm−1 at 20 and 50 °C, respectively. The solubility of the new polymeric ionic liquids, their thermal stability and their glass transition temperatures were investigated in detail. Ionic conductivities were found to depend on the nature of the counter‐anion and on the polymers' glass transition temperature rather than its molecular weight. magnified image