Viscoelastic properties of a branched liquid crystal in the nematic phase

Abstract

We report results from a comprehensive suite of measurements, including small angle X-ray scattering (SAXS), polarising optical microscopy, dynamic light scattering, elastic properties and dielectric and diamagnetic susceptibilities on macroscopic liquid crystalline properties of branched compound, 2-(octyloxycarbonyl)-1, 4-phenylene bis(4-(octyloxy)benzoate). SAXS studies reveal very distinct, although short-range smectic-C-type clusters, leading to increased viscosities, very similar to that been reported in many bent-core compounds. The measured elastic constants and their relative values are similar to calamitic liquid crystals, presumably because the clusters are not polar, unlike in bent-core liquid crystals, which (together with the director tilt) result in a layer chirality.

Keywords:

• Y-shaped molecules
• viscoelastic properties
• Freedericksz transition
• dynamic light scattering

Acknowledgements

The authors acknowledge valuable assistance from Vesna Stanic and Elaine diMasi for their expert assistance with the set-up and SAXS measurements on beamline X6B at NSLS.

Funding

The authors acknowledge support from the NSF [grant no. DMR-0964765]. Use of the National Synchrotron Light Source, Brookhaven National Laboratory, was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract no. DE-AC02-98CH10886.