# Macroscopic Biaxial Order in Multilayer Films of Bent-Core Liquid Crystals Deposited by Combined Langmuir–Blodgett/Langmuir–Schaefer Technique

## TL;DR

Researchers showed that bent-core liquid crystals can form ordered structures in multilayer films, which could help in understanding and controlling their unique properties.

## Contribution

Demonstration of macroscopic biaxial order in bent-core liquid crystal films using a combined deposition technique.

## Key findings

- Multilayer films of bent-core nematic exhibit macroscopic in-plane ordering.
- Long molecular axis tilts relative to the surface, and the short axis aligns with the compression direction.
- Combined Langmuir–Blodgett/Langmuir–Schaefer technique enables controlled ordering.

## Abstract

Bent-core liquid crystals, a class of mesogenic compounds with non-linear molecular structures, are well known for their unconventional mesophases, characterized by complex molecular (and supramolecular) ordering and often featuring biaxial and polar properties. In the nematic phase, their unique behavior is manifested in the formation of nano-sized biaxial clusters of layered molecules (cybotactic groups). While this prompted their consideration in the quest for nematic biaxiality, experimental evidence indicates that the cybotactic order is only short-ranged and that the nematic phase is macroscopically uniaxial. By combining atomic force microscopy, neutron reflectivity and wide-angle grazing-incidence X-ray scattering, here, we demonstrate that multilayer films of a bent-core nematic, deposited on silicon by a combined Langmuir–Blodgett and Langmuir–Schaefer approach, exhibit macroscopic in-plane ordering, with the long molecular axis tilted with respect to the sample surface and the short molecular axis (i.e., the apex bisector) aligned along the film compression direction. We thus propose the use of Langmuir films as an effective way to study and control the complex anchoring properties of bent-core liquid crystals.