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Analysis of impedance measurements of a suspension of microcapsules using a variable length impedance measurement cell

Dejan Križaj
Dejan Križaj
 oraz 
Borut Pečar
Borut Pečar
   | 21 paź 2012
Journal of Electrical Bioimpedance's Cover Image
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Article Category: Articles
Data publikacji: 21 paź 2012
Zakres stron: 42 - 50
Otrzymano: 23 lis 2011
DOI: https://doi.org/10.5617/jeb.215
Słowa kluczowe
© 2012 Dejan Križaj, Borut Pečar, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig. 1

a) simplified view of the measurement cell, b) complete measurement setup.
a) simplified view of the measurement cell, b) complete measurement setup.

Fig. 2

A suspension of paraffin microcapsules used as a media.
A suspension of paraffin microcapsules used as a media.

Fig. 3

a) medium (suspension) in the measurement cell and b) electrical equivalent of the measured impedance.
a) medium (suspension) in the measurement cell and b) electrical equivalent of the measured impedance.

Fig. 4

Measured and fitted real (a and b) and imaginary (c and d) part as a function of the distance between the electrodes. For each measured frequency one fitted curve as a linear function of the distance between the electrodes is obtained.
Measured and fitted real (a and b) and imaginary (c and d) part as a function of the distance between the electrodes. For each measured frequency one fitted curve as a linear function of the distance between the electrodes is obtained.

Fig. 5

Measured and extracted suspension impedance (specific complex resistivity) shown in the complex plane.
Measured and extracted suspension impedance (specific complex resistivity) shown in the complex plane.

Fig. 6

Typical models with impedances and admittances in the complex plane. Semicircles of impedance denote parallel connection of a capacitor and resistor while semicircle of the admittance denotes series connection.
Typical models with impedances and admittances in the complex plane. Semicircles of impedance denote parallel connection of a capacitor and resistor while semicircle of the admittance denotes series connection.

Fig. 7

The final model that modeled suspension impedance with smallest fitting error.
The final model that modeled suspension impedance with smallest fitting error.

Fig. 8

Possible physics based model that can explain the electrical characteristics of a suspension of microcapsules.
Possible physics based model that can explain the electrical characteristics of a suspension of microcapsules.

Fig. 9

The fitting between the physically based model and the measured impedance (specific complex resistivity) of a suspension.
The fitting between the physically based model and the measured impedance (specific complex resistivity) of a suspension.

Fig. 10

Double layer impedance extracted from the measured total impedance for different electrodes and media with a suspension of microcapsules or only KCl solution.
Double layer impedance extracted from the measured total impedance for different electrodes and media with a suspension of microcapsules or only KCl solution.

Fig. 11

Comparison of the impedance due to the suspension and the double layer. The columns from left to right present results for distance between the electrodes 0.5 cm, 5 cm and 10 cm, respectively. Rows from top to bottom represent graphs of (total and separated to double layer and suspension) absolute values of impedance, permittivity and specific resistivity, respectively.
Comparison of the impedance due to the suspension and the double layer. The columns from left to right present results for distance between the electrodes 0.5 cm, 5 cm and 10 cm, respectively. Rows from top to bottom represent graphs of (total and separated to double layer and suspension) absolute values of impedance, permittivity and specific resistivity, respectively.

Fig. 12

Solution permittivity determination error in case the double layer is not taken into account. Frequency range is from 20 Hz to 1 MHz, the distance between the electrodes is from 5 to 45 mm.
Solution permittivity determination error in case the double layer is not taken into account. Frequency range is from 20 Hz to 1 MHz, the distance between the electrodes is from 5 to 45 mm.

Fig. 13

Solution specific resistivity determination error in case the double layer is not taken into account. Frequency range is from 20 Hz to 1 MHz, the distance between the electrodes is from 5 to 45 mm.
Solution specific resistivity determination error in case the double layer is not taken into account. Frequency range is from 20 Hz to 1 MHz, the distance between the electrodes is from 5 to 45 mm.

Parameters extracted by fitting the model from Figure 7 to the measured and extracted impedance of a suspension.

Electrode materialρ (A) [Ωm]εr (B) 108 *ρ (C) [Ωm]εr (D) *109εr (E)
Cu0,3014,101,466263,9459,91714
Ag0,2149,941,464382,5951,46467
Au0,27911,191,465022,4962,93998

Parameters determined by fitting the determined impedance of the double layer to the model of a CPE element in series with a resistor.

Media, electrodesα[CPE]Rd[Ω]Q° [μF]
0,1M KCl, Cu0,402,3117,47
0,1M KCl, Ag0,732,745906,51
0,1M KCl, Au0,702,90537,37
paraffin microcapsules, Cu0,532,0879,00
paraffin microcapsules, Ag0,681,51072,78
paraffin microcapsules, Au0,710,01018,13
eISSN:
1891-5469
Język:
Angielski
Częstotliwość wydawania:
Volume Open
Dziedziny czasopisma:
Engineering, Bioengineering and Biomedical Engineering, Biomedical Electronics, Life Sciences, Biophysics, Medicine, Biomedical Engineering, Physics, Spectroscopy and Metrology
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