On the Phase Transition Behaviour of Binary Systems: Various Non-Nematic Solutes in Nematic Solvent (EBBA)

Abstract

Abstract Phase transition behaviour of the systems of EBBA with methyl alcohol (MeOH), 1.2-dibromo-ethylene (DBE), o-xylene, m-xylene, and p-xylene has been studied. The phase diagrams for each system have been determined by the polarizing microscope. The slopes, βn and Bi, of the nematic and the isotropic phase boundary lines in each system have been qualitatively described by the molecular field treatment proposed by Humphries. The order parameters for both cis-and trans-DBE in EBBA have been obtained from analyses of 1H-NMR spectra. In the nematic phase, they decrease with increase in temperature. In the nematic/isotropic coexisting phase (N/I phase), the order parameter for CIS-DBE is almost independent of temperature. The proton spin-lattice relaxation times (T1) in the MeOH/EBBA system have been measured by a pulse NM R technique. Little temperature dependence of T1 has been found in the N/1 phase region.c