Structure and ionic conductivity of liquid crystals having propylene carbonate unitsElectronic supplementary information (ESI) available: DSC diagrams for the mixtures of 4a, 4b and 4c with various amounts of LiTFSI; WAXS/SAXS of 4a and 4b mixed with 10 mol% LiTFSI, ionic conductivity measurements for 4b, 6 and 8 with various amounts of LiTFSI; NMR spectra of all compounds discussed in this paper. See DOI: 10.1039/c4ta05401f

• Main Authors: Eisele, Andreas, Kyriakos, Konstantinos, Bhandary, Rajesh, Schönhoff, Monika, Papadakis, Christine M, Rieger, Bernhard
• Format: Journal Article
• Language: English
• Published: 27.01.2015
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c4ta05401f

Liquid-crystalline compounds with a perfluorinated aromatic ring as the mesogenic core and a propylene carbonate unit were prepared and mixed with lithium bis(trifluoro-methanesulfonyl)-imide (LiTFSI). The self-assembly was driven by the interaction of the polar propylene carbonate unit. Thus it is one of the few examples of liquid crystals with only one phenyl group that is able to self-assemble. Small- and Wide angle X-ray scattering (SAXS/WAXS) measurements indicate that the molecules spontaneously formed a smectic phase. Calculation of the Li-salt dissociation from the data obtained by a combination of impedance spectroscopy measurements and diffusion experiments by 7 Li and 19 F pulsed field gradient (PFG) NMR revealed good dissociation properties of the compounds. The complex of (2-Oxo-1,3-dioxolan-4-yl)methyl 4-(decyloxy)-2,3,5,6-tetrafluorobenzoate ( 4b ) with LiTFSI exhibited anisotropic conductivity. The conductivity parallel to the smectic orientation was 125 times higher than perpendicular and is one of the best reported for liquid crystals with propylene carbonate fragments. Synthesis and investigation of liquid crystalline molecules with cyclic carbonate units, which exhibit spontaneous alignment and enhanced ionic conductivity.