초록 |
Recently, polymerized ionic liquids (PILs), with an ionic liquid (IL) moiety in each repeating unit, have stirred great interest in the fields of polymer chemistry, physics and materials science. Since PILs are single-ion conductors that are potentially useful for advanced energy storage, energy conversion, and electromechanical transduction devices, it is of great interest to understand structure-property relations. Here, we synthesize PILs with imidazolium cations covalently attached to the polymer chain with a variety of side chains and various IL counterions. The dependence of the glass transition temperature (Tg) and the dielectric constant (εs) on molecular volume (Vm) of the repeat unit for PILs, the IL monomers they were polymerized from and simple ionic liquids, are compared. For IL monomers and PILs, it becomes that the glass transition temperature (Tg) decreases exponentially with increasing Vm and the static dielectric constant (εs) increases linearly with increasing Vm. The ionic conductivity is proportional to the product of dielectric constant and ionic rearrangement frequency, with the proportionality constant determined by the molecular volume of the repeat unit, leading to insight regarding optimal design of imidazolium PILs for facile ion transport. |