Evidence of Cybotactic Order in the Nematic Phase of a Main-Chain Liquid Crystal Polymer with Bent-Core Repeat Unit

We report the synthesis and structural characterization of a main-chainliquid crystal polymer constituted by a 1,2,4-oxadiazole-based bent-core repeat unit.For the first time, a liquid crystal polymer made of bent mesogenic units isdemonstrated to exhibit cybotactic order in the nematic phase. Coupled with thechain-bond constraints, cybotaxis results in maximized molecular correlations thatmake this material of great potential in the search for the elusive biaxial andferroelectric nematic phases. Indeed, repolarization current measurements in thenematic phase hint at a ferroelectric-like switching response (upon application of anelectric field of only 1.0 V μm−1) that, albeit to be definitely confirmed bycomplementary techniques, is strongly supported by the comparative repolarizationcurrent measurements in the nematic and isotropic phases. Finally, the weak tendencyof this polymer to crystallize makes it possible to supercool the cybotactic nematic phase down to room temperature, thus, pavingthe way for a glassy phase in which the biaxial (and possibly polar) order is frozen at room temperature.