Ionic liquids bearing both liquid crystallinity and chirality are potentially applicable for chiral electrochemical syntheses and polymerizations. In this study, two types of chiral nematic liquid‐crystalline ionic liquids (N*‐LCILs) are developed to achieve asymmetric electrochemical polymerization without a supporting electrolyte and even a chiral dopant. N*‐LCILs are prepared i) by adding an axially chiral binaphthyl derivative as an external chiral dopant to imidazolium cation–based LCILs or ii) by incorporating a chiral binaphthyl phosphate as a counter anion in LCILs. Helical poly(3,4‐ethylenedioxythiophene) (H‐PEDOT) films are successfully synthesized through electrochemical polymerization of a dimer‐ or trimer‐type 3,4‐ethylenedioxythiophene (EDOT) monomer in an N*‐LCIL, where N*‐LCIL plays the role of both an asymmetric solvent and a supporting electrolyte. H‐PEDOT films have helically π‐stacked structures of conjugated chains and spiral morphologies consisting of one‐handed screwed fibril bundles. The plausible mechanism of the asymmetric electrochemical polymerization of EDOT in N*‐LCIL is proposed to elucidate the correlation of helical sense between the helically π‐stacked chains, screwed fibril bundles, and N*‐LCIL. The two present types of N*‐LCILs are the first to enable supporting electrolyte–free asymmetric electrochemical polymerization, and they have potential applications in various types of chiral electrochemical syntheses, expanding the potential utility of ionic liquids.
We synthesised novel imidazolium-based ionic liquids with thermotropic liquid crystallinity by introducing phenylcyclohexyl and/or cyanobiphenyl mesogenic cores and hexyl or dodecyl methine chains into both sites of imidazolium moieties facing bromide anions. The liquid crystalline ionic liquids (LCILs) thus synthesised showed a nematic or smectic mesophase in both the heating and cooling processes, indicating the enantiotropic nature of the liquid crystallinity. The LCILs bearing the same types of double mesogenic cores [LCIL-2] showed a smectic A phase in the temperature range from 115 to 175 1C, whereas the LCILs with different types of double mesogenic cores [LCIL-3 and LCIL-4] showed nematic phases in the temperature ranges from 58 to 88 1C and 43 to 95 1C, respectively. The axially chiral binaphthyl derivatives substituted by LC groups at the 2,2 0 , 6,6 0 positions of the binaphthyl rings were synthesised and used as chiral dopants with large helical twisting powers. The mixtures of the LCILs and the (R)-and (S)-binaphthyl derivatives exhibited induced chiral nematic phases with right-and left-handed helical senses, respectively.The ionic conductivities of the LCILs were evaluated to be 10 À7 -10 À4 S cm À1 , depending on the isotropic, LC, and crystal phases. The temperature dependence of the ionic conductivities indicates that the LCILs can be regarded as semi-conducting materials. The LCILs might be used as anisotropic ionic conductors and can even serve as anisotropic solvents and electrolytes in electrochemical polymerisations.
Hydrogel particles composed of poly(N-isopropylacrylamide) were used as a particulate steric stabilizer for the dispersion polymerization of styrene for the first time. The effects of the size and concentration of the hydrogel particles on the resultant polystyrene particles were investigated. As expected, the hydrogel particles indeed play the role of steric stabilizer for dispersion polymerization. Moreover, some of the resultant polystyrene particles were covered with hydrogel particles, which was confirmed by electron microscopy and X-ray photoelectron spectroscopy.
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