Ion Conductivity of Liquid Crystalline Poly(substituted methylene)s Bearing Ionic Liquid Moieties at the Side Chain Ends

We have measured the ionic conductivity (σ) of liquid crystalline poly(substituted methylene)s (PMs) bearing ionic liquid (IL) moieties attached to the main chain via alkyl spacers. Four types of PMs investigated, differing in main-chain stereoregularity (atactic or syndiotactic) and the number of methylene units in the alkyl spacer (n = 6 or 12), have twice the σ of conventional polyacrylate ILs with similar glass transition temperatures. The highest σ of 5.9 × 10−5 S cm−1 is measured for the atactic PM with n = 12 at 30 °C. Poly(ionic liquid)s (PILs) based on lquid crystalline poly(substituted methylene)s (PMs) has two-fold higher ionic conductivity (σ) than conventional PILs with similar glass transition temperature. The highest σ value measured for these polymers with molecular weights more than 105 kDa is 5.9 × 10−5 S cm−1, greater than the maximum value of 3.0 × 10−5 S cm−1 expected for PILs.