A Liquid Film Motor

TL;DR

This paper introduces a novel liquid film motor that uses electro-hydrodynamical effects to induce and control rotation in suspended liquid films with electric fields, enabling precise control over vortex velocity and chirality.

Contribution

It demonstrates a new electrically driven liquid film motor capable of full control over rotation direction and speed in water and other liquids, using a quasi two-dimensional electrolysis cell.

Findings

Liquid films can be made to rotate using electric fields.

Rotation depends on exceeding threshold voltages or fields.

The device works with both DC and AC electric fields.

Abstract

It is well known that electro-hydrodynamical effects in freely suspended liquid films can flow the liquid. Here we report a purely electrically driven rotation in water and some other liquid suspended films with full control on the velocity and the chirality of the rotating vortices. The device, which is called ``film motor'', consists of a quasi two-dimensional electrolysis cell in an external in-plane electric field, crossing the mean electrolysis current density. If either the external field or the electrolysis voltage exceeds some threshold (while the other one is not zero), the liquid film begins to rotate. The device works perfectly with both DC and AC fields.