Polyazomethine with m-tolylazo side groups: thermal,dielectric and conductive behaviour |
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Authors: | Sergei Bronnikov Sergei Kostromin Valentina Mustea?a Vasile Cozan |
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Institution: | 1. Russian Academy of Science, Institute of Macromolecular Compounds, St. Petersburg, Russian Federationbronnik@hq.macro.ru;3. Russian Academy of Science, Institute of Macromolecular Compounds, St. Petersburg, Russian Federation;4. Romanian Academy, Petru Poni Institute of Macromolecular Chemistry, Ia?i, Romania |
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Abstract: | Using solution polycondensation, a new polyazomethine with m-tolylazo side groups (PAz) exhibiting thermotropic liquid crystalline phase was synthesised and its chemical structure was characterised with generally accepted methods. Its phase transition temperatures were detected with both polarising optical microscopy and differential scanning calorimetry. Using dielectric spectroscopy method, both real and imaginary parts of the permittivity were investigated in wide regions of temperature (from ?100°C to 170°C) and frequency (from 1 Hz to 1 MHz). Analysis of frequency dependent permittivity allowed finding three relaxations (α, β1 and β2) in PAz. β-relaxations were described with the Arrhenius equation, whereas α-relaxation was described with the Vogel–Fulcher–Tammann equation. The alternating current conductivity (ACC) of PAz was studied in the same regions of temperature and frequency. The frequency dependent ACC was described with an exponent power equation. Presentation of ACC as a function of inverse temperature allowed us to describe ACC with the Arrhenius equation. |
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Keywords: | polyazomethines liquid crystal relaxations dielectric spectroscopy permittivity electrical conductivity |
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