Anomalous Effect of Flow Rate on the Electrochemical Behavior at a Liquid vertical bar Liquid Interface under Microfluidic Conditions

作者：Kaluza Dawid; Adamiak Wojciech; Kalwarczyk Tomasz; Sozanski Krzysztof; Opallo Marcin; Joensson Niedziolka Martin

来源：Langmuir, 2013, 29(51): 16034-16039.

DOI：10.1021/la403614z

We have investigated the oxidation of ferrocene at a flowing organic solventlaqueous electrolytelsolid electrode junction in a microfluidic setup using cyclic voltammetry and fluorescent laser scanning confocal microscopy. At low flow rates the oxidation current decreases with increasing flow, contrary to the Levich equation, but at higher flow rates the current increases linearly with the cube root of the flow rate. This behavior is explained using a simple model postulating a smallest effective width of the three-phase junction, which after fitting to the data comes to be ca. 20 mu m. The fluorescence microscopy reveals mixing of the two phases close to the PDMS cover, but the liquid vertical bar liquid junction is stable close to the glass support. This study shows the importance of the solid vertical bar liquid vertical bar liquid junctions for the behavior of multiphase systems under microfluidic conditions.

• 出版日期2013-12-24