Molecular engineering room-temperature bent-core nematics

Abstract

We report the transition temperatures for several series of structural variations on bent-core mesogens (BCMs) derived from the asymmetric oxazole biphenol mesogenic core. Trimethyl-substituted mesogens exhibit nematic phases that can be supercooled to room temperature. Preliminary X-ray diffraction (XRD) results confirm a cybotactic supramolecular organisation in these nematics; moreover, the splitting of the diffuse wide-angle XRD feature observed in trimethylated mesogens points to an enhanced biaxial orientational correlation in the transverse molecular packing compared to other BCMs. Finally, one of the trimethyl-substituted mesogens shows the formation of a room temperature metastable fibre-like crystalline order when supercooled in a magnetic field.

Keywords:

• bent-core mesogen
• non-linear mesogen
• biaxial nematic
• cybotactic nematic
• X-ray diffraction

Acknowledgements

FV and OF acknowledge I. F. Placentino (Università Politecnica delle Marche) and C. Ferrero (ESRF) for participating in the XRD measurements and F. Fauth, J. Gorini, E. Di Cola, and T. Narayanan (ESRF) for their technical support.

Additional information

Funding

ETS acknowledges support from the Cary C. Boshamer Professorship.