Fluorinated smectics – New liquid crystalline medium for smart windows and memory displays

Abstract 4′-Alkyl-4-alkoxy-3-fluorobiphenyls and laterally mono-, two- and three-fluorosubstituted 4″-alkyl-4-fluoroterphenyls were synthesized and used as the components of mixtures with a broad temperature range of the monolayer smectic A phase and the Cr-SmA 1 -Iso or Cr-SmA 1 -N-Iso phase sequence. Several ionic potassium complexes of 18-crown-6-ether and dibenzo-18-crown-6-ether with different anions (Br − , ClO 4 − , 4-octylphenolate, 3,4-difluorophenolate, 3,5-difluoro-4-cyanophenolate and 4-dodecylbenzenesulfonate) were prepared and their solubility and conductivity in fluorobenzene were measured. Properties of dynamic scattering and clear states (threshold and saturation voltages) of two types of mixtures (mixture A with Cr-SmA 1 -Iso and mixture B with Cr-SmA 1 -N-Iso phase sequences) doped with above mentioned ionic compounds have been tested. The mixture B has the smectic layers more defected and it shows excellent properties to design displays with memory or smart windows.