Real-time control of textile waterproof performance upon droplet impact

Droplet impact on permeable surfaces such as sieves, metallic meshes and textiles has attracted research interest as it is a process ubiquitous in many applications, from preventing stains and entrainment of rain drops in clothes to entrapment of aerosols through filters. Here, we aim to investigate whether textile wettability can be varied on demand by employing the dielectrowetting effect. Dielectrowetting occurs when a dielectric liquid is present within an electric field. By varying the strength of the electric field, we can control the dielectrophoretic force acting on the liquid. This dielectrophoretic force alters the energy balance, affecting the droplet spreading and penetration dynamics upon impact. Employing high-speed imaging, we study the behaviour of droplets during the first milliseconds after impact. A parametric analysis enables us to construct a regime map that identifies the conditions for penetration or no penetration of the droplet through the textile. Noteworthy is the observation that a droplet that would normally penetrate the textile, and disintegrate, can be captured on the textile in the presence of the dielectrophoretic force at a sufficient potential strength.