Apparatus and method to measure dielectric properties (ε′ and ε″) of ionic liquids

Attila Göllei, András Vass, Elisabeth Pallai, Miklós Gerzson, Lajos Ludányi, János Mink

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Conventional techniques for measurement of dielectric properties of ionic liquids or electrolyte solutions fail because the samples are largely short circuited by the high electrical conductance. The object of the author's research activity was to elaborate an apparatus (microwave dielectrometer) and method suitable to measure the dielectric constant (ε′) and loss factor (ε″) of well conducting ionic liquids and other solvents. This process is based on a revised waveguide method completed with an automatic calibration possibility. Contrary to conventional measuring methods this technique uses about 20 W/g power density. The measurements were carried out at 2.45 GHz frequency in the temperature range from 10 up to 100 °C. The obtained (ε′) and (ε″) values of different solvents were compared with several published (calculated and measured) data. Statistical analysis was used to determine the error of measurements and distilled water was chosen as a standard for study of data dispersion. To accomplish statistical analysis, namely, the dielectric characteristics have to be determined at the same temperature. The values of variances were less or equal 1 in case of ε′ and decrease with increasing temperature. In case of ε″ the variance data were much smaller.

Original languageEnglish
Article number044703
JournalReview of Scientific Instruments
Issue number4
Publication statusPublished - May 11 2009


ASJC Scopus subject areas

  • Instrumentation

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