Effect of solvent polarity on the self-assembly and dielectric dynamics of non-aqueous lyotropic liquid crystalline phases |
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Authors: | Ravi Kumar Shukla Kuldeep Kumar Raina |
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Institution: | 1. Materials Research Laboratory, School of Physics and Materials Science, Thapar University, Patiala 147004, Indiaravishukla82@gmail.com;3. Materials Research Laboratory, School of Physics and Materials Science, Thapar University, Patiala 147004, India |
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Abstract: | Binary mixtures comprising cetylpyridinium chloride and non-aqueous solvents of varying polarity ethylene glycol (ε ~ 37.2) and formamide (ε ~ 109)] were studied via X-ray diffraction, polarisation optical microscopy, differential scanning calorimetry and dielectric spectroscopy. Layered lamellar mesophase was observed in both mixtures. Formamide-based mesophase was found more ordered and stable up to higher temperature (140°C). Ordering and stability of the mesophase was explained considering the higher polarity and dipolar–dipolar interactions of formamide. Dielectric spectroscopy demonstrates the large magnitudes of capacitance and permittivity (Cp ≈ 9 µF and ε ≈ 2428) for mesophase derived from formamide. Dynamical relaxation parameters of both mixtures were discussed and correlated with their structural aspects. |
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Keywords: | lyotropic liquid crystalline phase cationic surfactants non-aqueous solvent dielectric spectroscopy Cole–Cole relaxation process |
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