Viscoelastic parameters and flexoelectric effect in a bent-core nematic liquid crystal studied by dynamic light scattering

Recent measurements of the flexure-induced electric polarization in certain bent-core nematics (BCNs) have demonstrated a giant flexoelectric effect [1]. We present a study of nematic elasticities and viscosities in one of these compounds, together with an attempt to characterize the flexoelectricity by its effect on director fluctuations. Our results combined with a reanalysis of earlier data indicate that the flexoelectricity is a phenomenon distinct from the ordinary director modes; additionally we observe unusual, very slow fluctuations in polarized scattering which suggest the BCN has a heterogeneous, ``glassy'' character. Dilution in a miscible calamitic indicates a dramatic development of the slow dynamics between 30 wt {\%} and 60 wt {\%} BCN. We suggest a model to account for both our present results and the giant flexoelectricity discovered in [1]. Reference: [1] J. Harden \textit{et al}., \textit{Phys. Rev. Lett., 97,} 157802 (2006). Acknowledgement: NSF DMR-0606160.