Highly fluorinated sulfamates with thermotropic liquid crystalline properties

Abstract

Two original series of highly fluorinated sulfamates and biphenyls having thermotropic mesophases are synthesised and their liquid crystal properties are studied by differential scanning calorimetry (DSC) and polarising optical microscopy (POM). Fluorinated sulfamates exhibit wide mesophasic temperature ranges (48.3–140.5°C). However, the fluorinated biphenyls, usually described as liquid crystals, are instable and mesophases cannot be determined. The unexpected enantiotropic mesophases relationship of fluorinated sulfamates has been reported in this work. Two structural parameters are discussed, the length of both fluorinated tail and hydrocarbon linker.

Keywords:

• perfluorinated
• sulfamates
• structure–property relationship
• thermotropic
• mesophases