Determination of polarity parameters for liquid crystals using solvatochromic method in anisotropic and isotropic phases |
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Authors: | Amid Ranjkesh Meisam Hagh Parast Ji-Sub Park Jun-Chan Choi |
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Institution: | 1. School of Electronics Engineering, Kyungpook National University, Daegu, Korea;2. Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz, Iran |
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Abstract: | The use of liquid crystals (LCs) as anisotropic solvents is desired for various potential applications and usually for other organic and inorganic compounds. In this work, solvent polarity parameters are obtained using a spectroscopic method for four LCs with a range of high and low dielectric anisotropy (?ε). Solvatochromic polarity parameters for these LCs were defined via Kamlet–Abboud–Taft polarity functions characterizing different temperatures and phases, isotropic and anisotropic, and using the Reichardt’s dye and 2,6-diphenyl-4-(2,4,6-triphenyl-1-pyridinio) phenolate standard probe. The investigated polarity parameters reveal the effects of LC media on the photo-physical behaviour of solute molecules in isotropic and anisotropic media. Subsequently, a new LC polarity parameter (Zo) is introduced as an overall matrix anisotropy polarity parameter to characterize variation between isotropic and anisotropic phases. The values of Zo are sorted from higher to lower dielectric anisotropies (?ε). |
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Keywords: | Solvatochromism probe mixture liquid crystal matrix anisotropy Kamlet–Abboud–Taft polarity function |
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