Self‐assembly, mesomorphic behavior, and ionic conductivity of polymerized ionic liquid crystals with a threshold switching characteristic

Abstract

A series of pyridinium‐based polymerized ionic liquid crystals (PILCs) with different anions were synthesized, including poly(pyridinium bromide)s and poly(pyridinium trifluoroacetate)s, and their chemical structure, liquid‐crystalline properties and conductivity properties were investigated by many experimental techniques. At low temperature, some PILCs containing less cholesteryl mesogens presented smectic A phases; while the PILCs containing more cholesteryl mesogens displayed bicontinuous cubic phases. At high temperature, all the PILCs showed nematic phases. Compared with the corresponding poly(pyridinium bromide)s based on identical polymer cations, the poly(pyridinium trifluoroacetate)s showed lower glass transition and isotropic transition temperature. The PILCs displayed excellent temperature‐dependent ionic conductivity, making it attractive for applications in temperature‐controlled electronic switches. In cubic and smectic A phases, the PILCs presented Arrhenius‐like ionic conductivity behavior, and they exhibited Vogel–Fulcher–Tammann‐like behavior in nematic phases.

Advanced research and prospects on polymer ionic liquids: trends, potential and application

“…54 PILs incorporating poly( pyridinium bromides) and poly ( pyridinium trifluoroacetates) were synthesized using an end pyridine-containing monomer and a dibromalkyl LC monomer with cholesterol groups. 55 The ionic conductivity of these new PILs increased as the temperature increased from 95 to 242 °C. The temperature-dependent conductivity of the PILCs exhibited a transition from Arrhenius-like behavior to Vogel-Fulcher-Tamman-like behavior in nematic phases.…”

Fast thermally-responsive azatriphenylene ionic discotic liquid crystalline polymers with shape-memory properties

“…These materials have applications in diverse fields, such as solid electrolytes, separation membranes, ionic conductivity materials, photochemical materials, and soft actuators. [7][8][9][10][11][12][13][14] Most of the investigated ILCPs are based on rodshaped mesogens and primarily form smectic and nematic phases. [15][16][17][18][19] For example, Ujiie et al 20 investigated the synthesis of ILC copolymers via quaternary amination reactions involving nonionic counterparts and hydrobromic acid.…”