Synthesis and solid-state properties of thermotropic liquid crystalline polypeptide bearing imidazolium and p-tolyl groups

Polypeptides bearing imidazolium and p -tolyl groups have been synthesized by click chemistry between poly(γ-3-azidopropyl- l -glutamate) (PAPLG) and 3-butyl-1-propargyl imidazolium bromide (BPIB) and 1-methyl-4-prop-2-ynyloxybenzene (MPB). The FTIR results revealed α -helical conformation of all resulting polypeptides in the solid-state. POM and WAXS study revealed that polypeptides with high p -tolyl contents (molar percentage ⩾54%) possessed nematic liquid crystalline phases and hexagonal packing in the solid-state. DSC analysis revealed the solid to liquid crystalline transitions in the temperature range of 35–42 °C.