Title :
Dielectric response of binary mixture of nematic and cholesteric liquid crystals
Author :
Johri, G.K. ; Sharma, Ritu ; Johri, M. ; Yasumoto, Kiyotoshi
Author_Institution :
Dept. of Phys. & Electron., D.A-V. Coll., Kanpur, India
Abstract :
The dielectric response of binary mixture of liquid crystals 4 -cyano -4-pentyl - biphenyl and Cholesteryl Oleyl Carbonate as a function of temperature has been studied. The microwave cavity spectrometer has been used to measure the relative shift, width and amplitude of the resonance profile at a fixed frequency 9.0G Hz. The Slater´s perturbation equations have been used to analyze the measured data and permittivity and dielectric loss has been studied in terms of relative shift and relative width respectively. The relaxation time has also been calculated. The transition temperature for the mixture has been found as modified from those of constituent liquid crystals considered and transition temperatures for mixture are 296.8 and 323K. The shift of transition is towards nematic liquid crystal.
Keywords :
cholesteric liquid crystals; dielectric losses; dielectric materials; dielectric relaxation; nematic liquid crystals; organic compounds; permittivity; perturbation theory; 4 -cyano -4-pentyl - biphenyl; 9 GHz; Slaters perturbation equations; cholesteric liquid crystals; cholesteryl oleyl carbonate; dielectric loss; dielectric response; microwave cavity spectrometry; nematic liquid crystals; permittivity; relaxation time; resonance profile; transition temperature; Dielectric liquids; Dielectric loss measurement; Dielectric measurements; Electrochemical impedance spectroscopy; Frequency measurement; Liquid crystals; Loss measurement; Microwave measurements; Permittivity measurement; Temperature;
Conference_Titel :
Properties and Applications of Dielectric Materials, 2003. Proceedings of the 7th International Conference on
Print_ISBN :
0-7803-7725-7
DOI :
10.1109/ICPADM.2003.1218469