Novel Electrochemical Flow Sensor Based on Sensing the Convective-Diffusive Ionic Concentration Layer

Area of Science:

• Electrochemistry
• Microfluidics
• Sensor Technology

Background:

• Ionic concentration-polarization (CP) is a key phenomenon in microchannel-ion permselective membrane systems.
• Understanding the influence of advection on CP is crucial for developing advanced sensing technologies.

Purpose of the Study:

• To present a novel flow sensor based on electrochemical sensing of the CP layer.
• To investigate the effect of advection on transient and steady-state CP phenomena in microchannel-Nafion membrane systems.
• To explore two distinct methods for flow estimation using this sensor.

Main Methods:

• Development of a microchannel-ion permselective membrane device for electrochemical sensing.
• Measurement of local impedance using embedded electrode pairs.
• Monitoring of total current across the permselective medium.
• Examination of stepwise CP application under steady-state flow and stepwise flow under steady-state CP.

Main Results:

• Demonstrated the working principle of the electrochemical flow sensor.
• Quantified the effect of advection on the ionic CP layer.
• Validated local impedance and total current as effective parameters for flow estimation.

Conclusions:

• The novel electrochemical sensor shows promise for accurate fluid flow measurement.
• The study provides insights into the interplay between advection and ionic CP in microfluidic devices.
• This technology offers a new approach for microflow sensing applications.