Non-Standard Electroconvection in a Bent Core Nematic
David B. Wiant
,Jim T. Gleeson
kent state u., phys. dept.
kent state phys.
2research institute for solid state physics and optics, hungarian acad. of sciences
3institute for solid state physics and optics, hungarian acad. of sciences
4lci, kent state u.
We characterize three non-standard electrohydrodynamic instabilities in
nematic liquid crystals composed of bent core
molecules. In addition to their shape, another important attribute of this material is that
the anisotropy in the electrical conductivity changes
sign as the frequency of the applied electric field changes.
These instabilities do not appear to fit within
the standard model for electroconvection. The first instability creates a pattern with stripes
parallel to the initial director orientation, with a wavelength about
equal to the separation of the cell plates. The next is
the previously reported prewavy instability. The third instability is
optically and dynamically identical to the prewavy instability, but is
distinguished by different threshold behavior.