Magneto Twister: Magneto Deformation of the Water-Air Interface by a Superhydrophobic Magnetic Nanoparticle Layer

Abstract

[EN] Remote manipulation of superhydrophobic surfacesprovides fascinating features in water interface-related applications. Asuperhydrophobic magnetic nanoparticle colloid layer is able to float on the water-air interface and form a stable water-solid-air interface dueto its inherent water repulsion, buoyancy, and lateral capillarity properties. Moreover, it easily bends downward under an externally applied gradient magnetic field. Thanks to that, the layer creates a stabletwister-like structure with aflipped conical shape, under controlled waterlevels, behaving as a soft and elastic material that proportionally deformswith the applied magneticfield and then goes back to its initial state in the absence of an external force. When the tip of the twister structure touches the bottom of the water container, it provides a stable magnetomovable system, which has many applications in the microfluidicfield.We introduce, as a proof-of-principle, three possible implementations of this structure in real scenarios, the cargo and transport of water droplets in aqueous media, the generation of magneto controllableplugs in open surface channels, and the removal of floating microplastics from the air-water interface