A ferronematic liquid crystal (FNLC) system containing 8CB (4-cyano-4'-[n-octylbiphenyl]) and magnetite particles was prepared by using the two steps method. The magnetite particles were dispersed in the organic (liquid crystalline) media by using toluene. However, the toluene affected the thermotropic and structural behaviour of the pure basic (8CB) substance, drastically. The product was stable as no any sedimentation and coagulation has been observed during several weeks after the preparation. However, the distribution of magnetite particles was found not to be homogeneous in the nm size range.
Authors:Gy. Fetter, A. Szilágyi, M. Zrínyi, and A. Bóta
The thermotropic behaviour of the Synperonic A7-water (80%) system was investigated by different (SAXS, freeze-fracture, DSC) methods under the conditions of steady state and shear stress. It was found that above the melting point (about 55°C) lamellar structure exists at 80°C, which was interpreted as a consequence of phase separation. The phase separation is more extended if the sample was sheared. The shear process affects the thermotropic behaviour of the system drastically. Above the melting point the thermal treatment terminates the shear prehistory. The shear processes were executed in a shear cell constructed in two variants for small angle X-ray scattering and for freeze-fracture methods.