TY - JOUR
T1 - Taming Electrowetting Using Highly Concentrated Aqueous Solutions
AU - Papaderakis, Athanasios
AU - Polus, Kacper
AU - Kant, Pallav
AU - Box, Finn
AU - Etcheverry, Bruno
AU - Byrne, Conor
AU - Quinn, Martin
AU - Walton, Alex
AU - Juel, Anne
AU - Dryfe, Robert
PY - 2022/12/15
Y1 - 2022/12/15
N2 - Wetting of carbon surfaces is one of the most widespread, yet poorly understood, physical phenomena. Control over wetting properties underpins the operation of aqueous energy storage devices and carbon-based filtration systems. Electrowetting, the variation in contact angle with applied potential, is the most straightforward way of introducing control over wetting. Here, we study electrowetting directly on graphitic surfaces, with the use of aqueous electrolytes, to show that reversible control of wetting can be achieved, and quantitatively understood, using models of the interfacial capacitance. We manifest that the use of highly concentrated aqueous electrolytes induces a fully symmetric and reversible wetting behavior, without degradation of the substrate, within the unprecedented potential window of 2.8 V. We demonstrate where the classical “Young-Lippmann” models apply, and break down, and discuss reasons for the latter, establishing relations among the applied bias, the electrolyte concentration and the resultant contact angle. The approach is extended to electrowetting at the liquid|liquid interface, where a concentrated aqueous electrolyte drives reversibly the electrowetting response of an insulating organic phase with a significantly decreased potential threshold. In summary, this study highlights the beneficial effect of highly concentrated aqueous electrolytes on the electro-wettability of carbon surfaces, being directly related to the performance of carbon-based aqueous energy storage systems, electronics and microfluidics devices.
AB - Wetting of carbon surfaces is one of the most widespread, yet poorly understood, physical phenomena. Control over wetting properties underpins the operation of aqueous energy storage devices and carbon-based filtration systems. Electrowetting, the variation in contact angle with applied potential, is the most straightforward way of introducing control over wetting. Here, we study electrowetting directly on graphitic surfaces, with the use of aqueous electrolytes, to show that reversible control of wetting can be achieved, and quantitatively understood, using models of the interfacial capacitance. We manifest that the use of highly concentrated aqueous electrolytes induces a fully symmetric and reversible wetting behavior, without degradation of the substrate, within the unprecedented potential window of 2.8 V. We demonstrate where the classical “Young-Lippmann” models apply, and break down, and discuss reasons for the latter, establishing relations among the applied bias, the electrolyte concentration and the resultant contact angle. The approach is extended to electrowetting at the liquid|liquid interface, where a concentrated aqueous electrolyte drives reversibly the electrowetting response of an insulating organic phase with a significantly decreased potential threshold. In summary, this study highlights the beneficial effect of highly concentrated aqueous electrolytes on the electro-wettability of carbon surfaces, being directly related to the performance of carbon-based aqueous energy storage systems, electronics and microfluidics devices.
U2 - 10.1021/acs.jpcc.2c06517
DO - 10.1021/acs.jpcc.2c06517
M3 - Article
JO - The Journal of Physical Chemistry Part C: Nanomaterials, Interfaces and Hard Matter
JF - The Journal of Physical Chemistry Part C: Nanomaterials, Interfaces and Hard Matter
SN - 1932-7447
ER -