Details

Autor(en) / Beteiligte

• Rzoska, Sylwester J
• Drozd-Rzoska, Aleksandra
• Mukherjee, Prabir K
• Lopez, David O
• Martinez-Garcia, Julio C

Titel

Distortion-sensitive insight into the pretransitional behavior of 4-n-octyloxy-4′-cyanobiphenyl (8OCB)

Ist Teil von

• Journal of physics. Condensed matter, 2013-06, Vol.25 (24), p.245105-245105

Ort / Verlag

Bristol: IOP Publishing

Erscheinungsjahr

2013

Quelle

MEDLINE

Beschreibungen/Notizen

• Results of studies of the static and dynamic dielectric properties in rod-like 4-n-octyloxy-4′-cyanobiphenyl (8OCB) with isotropic (I)-nematic (N)-smectic A (SmA)-crystal (Cr) mesomorphism, combined with measurements of the low-frequency nonlinear dielectric effect and heat capacity are presented. The analysis is supported by the derivative-based and distortion-sensitive transformation of experimental data. Evidence for the I-N and N-SmA pretransitional anomalies, indicating the influence of tricritical behavior, is shown. It has also been found that neither the N phase nor the SmA phase are uniform and hallmarks of fluid-fluid crossovers can be detected. The dynamics, tested via the evolution of the primary relaxation time, is clearly non-Arrhenius and described via τ(T) = τc(T−TC)−φ. In the immediate vicinity of the I-N transition a novel anomaly has been found: Δτ ∝ 1 (T − T*), where T* is the temperature of the virtual continuous transition and Δτ is the excess over the 'background behavior'. Experimental results are confronted with the comprehensive Landau-de Gennes theory based modeling.