Nano-segregated polymeric film exhibiting high ionic conductivities

Abstract

Nanostructures can be used for the fabrication of highly functional materials transporting ions and charges. We demonstrate a new design strategy for polymeric higher ion-conductors. Phase-segregated layers of alternating mobile tetra(ethylene oxide)s (TEOs) and rigid aromatic cores where the TEO moieties are grafted from aromatic layers have been shown to be efficient to transport lithium triflate. Such segregated structures at the nanometer scale (nano-segregated structures) were prepared by in-situ photopolymerization of an aligned methacrylate liquid crystalline monomer comprising a terphenyl rigid rod mesogen having a TEO terminal chain. The ion-conductive TEO moiety remains in the highly mobile state even after polymerization, which is indicated by its low glass transition temperature (-45 degrees C). This nanostructured film exhibits an ionic conductivity parallel to the layer of 10(-3) S cm(-1) at room temperature. The highest ionic conductivity is in the level of 10(-2) S cm(-1) observed at 150 degrees C. The anisotropic ionic conductivities have been observed for the nano-segregated film.