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Impedance spectroscopy of liquids in microchannels: experimental principles and applications
Supervisior: Dipl.-Ing. Dr. Andreas Tröls
Co-Supervisor: Univ.-Prof. Dr. Marco Da Silva
![[Translate to Englisch:] Phillip Reisner](/fileadmin/_processed_/b/4/csm_Phillip_Reisner_330_385_f59a892ed3.png)
The impedance spectrum of a liquid, which is relatively easy to determine, is significantly influenced by numerous physical and chemical properties. Using a microchannel fabricated in PDMS and equipped with two electrodes for impedance spectroscopy, the following investigations were carried out: The influence of volume flow rate and conductivity on the impedance spectrum was determined.
Fig. 1: This figure shows a rendering of the microchannel used with dimensions of the electrodes
From the knowledge of the structure of the microchannel and the physical effects taking place in it, an equivalent circuit could be determined. Using curve fitting, it was possible to determine from the measurement data and the equivalent circuit which physical properties in the microchannel are influenced by the variation of the volume flow and the conductivity. Further research in this area could be used to design a flow sensor based on impedance spectroscopy.
Fig. 2: This figure shows the effect of conductivity on the impedance spectrum in the Nyquist diagram
Keywords: Impedance spectroscopy, microchannel, volume flow, conductivity, curve fitting
June 06, 2023
