On the electrochemical flow measurements using carbon-based screen-printed electrodiffusion probes

Abstract

In this article, we have studied the possibility of using carbon-based screen-printed probes for electrochemical flow and mass flux measurements. Such probes have, up to now, been mainly used as biosensors to study in vivo reactions. Our study shows that screen-printed sensors allow the measurement of mass flux and mean wall shear stress with good accuracy and high reproducibility. The existence of a micro-porous layer covering the surface of screen-printed electrodes has been revealed by means of the impedance measurements and has been confirmed by Scanning Electron Microscopy. This layer influences the statistical characteristics of the turbulent limiting diffusion current and should be taken into account as an additional transfer function between the current and the velocity fluctuations. The use of screen-printed sensors opens new possibilities in the field of electrochemical flow diagnostics. The advantage of this new manufacturing technology lies in the possibility of serial mass production at very competitive prices (disposable sensors) combined with the possibility of the manufacture of segmented electrodes or matrix of electrodes. These new possibilities can be used for various industrial applications as well as for scientific studies on near-wall turbulent mass transfer. Furthermore, it is possible to envisage the development of a hybrid sensor (electrodiffusional/biochemical) allowing the study of in situ biochemical reactions in a flow

Electrodiffusion diagnostics of laminar flows using the delay-time method

“…The electrochemical (electrodiffusion) diagnostics of flows are widely used for the measurements of the wall velocity gradient and the local wall shear stress s w in electrolyte solutions [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. This method is based on the measurement of the limiting diffusion current I on small flush-mounted electrodes.…”