Apparatus and method to measure dielectric properties (epsilon(') and epsilon(')) of ionic liquids

作者：Gollei Attila^*; Vass Andras; Pallai Elisabeth; Gerzson Miklos; Ludanyi Lajos; Mink Janos

来源：Review of Scientific Instruments, 2009, 80(4): 044703.

DOI：10.1063/1.3117352

• dielectric losses
• electrolytes
• microwave devices
• microwave measurement
• permittivity
• permittivity measurement
• statistical analysis
• water

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 (epsilon(')) and loss factor (epsilon(')) 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 degrees C. The obtained (epsilon(')) and (epsilon(')) 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 epsilon(') and decrease with increasing temperature. In case of epsilon(') the variance data were much smaller.

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  中国人民解放军国防大学