GAS-BUBBLES ELECTROLYTICALLY GENERATED AT MICROCAVITY ELECTRODES USEDFOR THE MEASUREMENT OF THE DYNAMIC SURFACE-TENSION IN LIQUIDS

A new method is proposed for the measurement of dynamic surface tensio n in aqueous solutions. The advantage of this method with respect to t he classical method based on sparging is that the use of gas pumps is avoided, resulting in a miniaturized system. This method is based on t he in situ generation of gas bubbles by means of electrolysis at micro cavity electrodes (MCEs). As a consequence of electrode surface shapin g, a single nucleation site for gas bubbles is created. The MCE is use d simultaneously as a bubble actuator (generator) and as a bubble size and/or frequency sensor. Measurement results prove the suitability of the electrolytic method for the monitoring of the dynamic surface ten sion in aqueous solutions.