Design and Characterization of Liquid Crystal−Graphite Composite Electrodes

Abstract

Thermotropic ionic liquid crystals (ILCs), 1,1′-dialkyl-4,4′-bipyridinium bis(triflimide)s have been used as binders to fabricate new carbon composite electrodes. ILC compounds possess an ordered molecular orientation, and upon mixing with graphite, ILCs retain their liquid crystal characteristics and thus their ordered arrangement. The electrochemical performances of these composite electrodes were evaluated by using different electrochemical probes. The resulting electrodes offer high electrochemical reactivity, low background current, improved signal-to-noise ratio, greater stability, excellent mechanical strength, and very good antifouling effects. It is believed that the higher conductivity of ILCs as well as the ordered orientation of these thermotropic ILCs which cause an increase in the edge-plane sites of these composite electrodes are responsible for the promotion of their electrocatalytic activities and antifouling effects. Such characteristics make these composite electrodes ideal for use in different electrochemical and biosensing applications.

Percolation Phase Transition from Ionic Liquids to Ionic Liquid Crystals

“…Some experiments (31,32) reported similar observations, but the exact transition point may vary according to different conditions, such as temperature, type of ions, etc. The purpose of this work is not pinpointing the exact transition point, rather it provides a qualitative and general theoretical framework for understanding the phase behavior of ILs changing from the NSL phase to the ILC phase with increasing cationic side-chain length, which may be very important for the applications of ILs and ILCs in dye-sensitized solar cells (33), electrofluorescence switches (34), electrolytes for Li-ion batteries (35) and electrochemical sensors (36).…”

“…Some experiments(31,32) reported similar observations, but the exact transition point may vary according to different conditions, such as temperature, type of ions, etc. The purpose of this work is not pinpointing the exact transition point, rather it provides a qualitative and general theoretical framework for understanding the phase behavior of ILs changing from the NSL phase to the ILC phase with increasing cationic side-chain length, which may be very important for the applications of ILs and ILCs in dye-sensitized solar cells(33), electrofluorescence switches(34), electrolytes for Li-ion batteries(35) and electrochemical sensors(36).With complex molecular structures and interactions, complex liquids frequently exhibit complex phase behaviors beyond the description of simple liquid theories. Therefore, the identification methods for the phase transition of simple liquids, such as the translation and orientation correlation functions, may not be applicable to determining the phase transitions of complex liquids.…”

1,2,4-Triazolium ions as flexible scaffolds for the construction of polyphilic ionic liquid crystals

“…Ionic liquid crystals (ILCs) are organic materials combining the low volatility and solvent properties of ionic liquids (ILs) with the intrinsic order and anisotropy of liquid crystals (LCs). 1 They can be exploited as electrolytes for batteries, 2 in electrochemical sensors, 3,4 dye-sensitised solar cells, 5 in water desalination membranes, 6 as solvents in extraction processes, 1 or as media for chemical reactions. 7 The majority of previous work on ILCs has been based on a limited number of cationic core structures, most commonly imidazolium and pyridinium ions.…”

Thermotropic Ionic Liquid Crystals

“…In addition, these compounds displayed efficient electrochromism in the liquid crystalline bulk state [ 176 ]. The viologen-based mesogens 73 ( Scheme 16 ) have been used to fabricate carbon composite electrodes, with the purpose to improve their characteristics [ 177 ].…”