Liquid-Crystalline Complexes of Mesogenic Dimers Containing Oxyethylene Moieties with LiCF₃SO₃:  Self-Organized Ion Conductive Materials

Abstract

Mesomorphic dimeric compounds consisting of rigid mesogenic cores and flexible oxyethylene chains have been prepared as liquid-crystalline materials capable of complexing with ionic species. The incorporation of LiCF3SO3 into these materials results in the induction of smectic A phases and significant mesophase stabilization. The ion−dipole interactions between lithium ions and oxyethylene moieties have stabilized the mesomorphic layer structures. Ionic conductivities have been measured for the complexes forming homeotropically aligned molecular orientation of smectic phases. The highest value of conduction, which is observed for the direction parallel to the layer in the smectic A phase, is 5.5 × 10-4 S cm-1. These results suggest that the complexes of LiCF3SO3 with mesogenic rod−coil−rod molecules containing oxyethylene chains can function as self-organized ion conductive materials.

Electrofluorochromism in π-conjugated ionic liquid crystals

“…We have preliminary measured ionic conductivities of compounds 1 and 2 perpendicular to the long molecular axis (planar alignment conditions), by electrochemical impedance spectroscopy using the ITO liquid crystalline cell as a parallel plate capacitor ( Supplementary Fig. 3) 28,29 . Conductivity values as high as 10 À 4 S cm À 1 were found, indicating that mesophase nanosegregation effectively create ion conducting pathways within the materials.…”

“…Supplementary Figure 3 displays a representative impedance spectrum of 1 at 120°C where a high frequency relaxation process ( relaxation frequency B400 Hz) and an incomplete low frequency one can be seen. The first process is attributed to the bulk resistance of the material (R b ) while the latter is associated with the charge transfer resistance of the interface between sample and electrode [26][27][28][29] . Ionic conductivity (s) was calculated using the equation (1):…”

“…where K cell is the cell constant given by the ratio between cell gap and electrode area [26][27][28][29] . R b was obtained from the semicircle diameter on the real axis (Z 0 ) ( Supplementary Fig.…”

“…R b was obtained from the semicircle diameter on the real axis (Z 0 ) ( Supplementary Fig. 3) by fitting the experimental spectral points with two resistance-capacitor (RC) circuits in series [26][27][28][29] .…”

Transport and Electro‐Optical Properties in Polymeric Self‐Assembled Systems

“…Mesomorphic dimeric compounds consisting of rigid mesogenic cores and flexible oxyethylene chains are able to complex CF 3 SO 3 Li to form a lamellar smectic self-assembly (Fig. 3.15) [268]. The ionic conductivity is anisotropic and reaches 5.5´10 -4 S cm -1 parallel to the layers.…”