Electropneumatic Surfaces: Pairing Electrowetting and Air Pressure for Reversible Droplet Mobility Switching

Abstract

Abstract Designing surfaces with controllable wettability and exploring methodologies for manipulating liquid motion on solid surfaces is an important research challenge. The impact on various interdisciplinary applications, ranging from self‐cleaning technology to the handling of droplets on Lab‐on‐a‐Chip self‐diagnostic devices, is expected to be significant. In this work, it is studied how the combined action of electric fields and pneumatic actuation can be used to achieve wetting transitions from states where droplets stick to surfaces, to states where droplets slide easily with low friction. The manipulation of water droplets on air‐permeable porous surfaces using both electric fields (electrowetting) and air‐pressure is investigated. The control over droplet mobility is achieved by tuning the solid‐liquid adhesion upon voltage application, in order to pin the droplet; de‐pinning is achieved by air pressure application through surface pores. This way low energy consumption and efficient switching between extreme wetting states and droplet mobility are realized.

Keywords

• droplet manipulation
• electrowetting
• functional surfaces
• pneumatic actuation