抄録
The visco-clastic properties for binary mixtures of 6OCB/8OCB are investigated by a light scattering technique with an application of voltages. The mixtures exhibit a reentrant nematic phase between the smectic and crystal phases in the range of 22.0 to 29.5 wt% of 6OCB content. The viscosity and the elastic constant increase with cooling both in the nematic and reentrant nematic phases. It is also found that the viscosity and the elastic constant show an anomalous increase near the phase transition temperature, namely a pretransitional phenomenon. The activation energies for viscosity differ in the nematic and reentrant nematic phases, depending on the 6OCB content. Moreover, the visco-elastic behavior depends on the specific time during which the sample is kept in the smectic A phase. These results confirm that the formation of dimers plays an important role in the reentrant phenomenon of this system.
