Charge-controlled wetting and electromechanical energy conversion

Description

Interfacial charges have a profound impact on wetting. They can change contact angles by
several tens of degrees and even induce transitions from partial to complete wetting. Interfacial charges can change either by spontaneous physico-chemical processes at interfaces, or they can be tuned by applying voltages to external control electrodes. In both cases, an initial electric phenomenon gives rise to a mechanical response of the system. If, conversely, a drop is forced to mechanically move along or fall onto a surface in the presence of charges, part of the mechanical energy in the system can be converted into electrical electric energy by means of electrical induction and – using suitable external circuitry – can be harvested for other purposes.
In this lecture, I will discuss several examples to illustrate the coupling between electrical and
wetting phenomena, starting from the electrically induced mechanical motion of droplets in
electrowetting to the reverse harvesting of electric energy from falling drops. I will focus in
particular on the conditions required to optimize the efficiency of the latter process. Next to the macroscopic response, some aspects of physico-chemical charge generation at solid-liquid interfaces will be discussed.

Period	16 Aug 2021
Event title	Droplets 2021
Event type	Conference
Location	Darmstadt , GermanyShow on map