Measurements of the Bend and Splay Elastic Constants of Octyl-Cyanobiphenyl

Publisher Website
Google Scholar
Abstract
The bend (K33) and splay (k11 elastic constants of octylcyanobiphenyl have been measured as a function of temperature using the electric field induced Freedericksz transition. We have made simultaneous measurements of the dielectric constants and birefringence of 8CB using a cell with homogeneous alignment. Dielectric constants were measured using an AC bridge, while the birefringence was obtained using an interferometric technique. The sample temperature was controlled to better than ±0.1 mK. Both the dielectric and optical data were analysed to yield the splay and bend elastic constants and the critical exponent associated with the divergence of K33 near the Nematic to Smectic A phase transition. The validity of the assumption of linear elastic response at temperatures close to the phase transtion is discussed.