Flexible sensors based on two conductive electrodes and MWCNTs coating for efficient pH value measurement

Abstract

© 2019 The measurement of pH value of solutions is crucial in many fields of modern science. We deposited MWCNTs coating on a planar capacitive structure consisting of interdigitated gold and aluminium electrodes on a flexible Kapton foil substrate, to develop the pH sensors. MWCNTs coating acts as an H+ ion sensing layer. The complete structural, mechanical and electrical characterization has been performed. The sensors involve supplying gold/aluminium electrodes with an input voltage and measuring the changes in the capacitance, resistance and impedance when the sensor chip is exposed to different pH solutions. The experimental setup was built for dipping the sensors in the sample liquids of different pH values from 4 to 9, being very flexible, reproducible and robust.