Experimental Study of the Wettability of Droplets on Superhydrophobic Surfaces Regulated by Magnetic Field

Abstract Magnetic field regulates the change of wettability of water drops on superhydrophobic surfaces, which is important in the fields of biomedicine, chemical materials, energy, printing, and surface cleaning. This paper prepared superhydrophobic surfaces using low surface energy silica nanometer particles as substrates, which had a maximum contact angle of 151.5°. Magnetic field-regulated wettability change experiments were performed on water droplets placed on a superhydrophobic silica surface. First, the deionized water was magnetized to reduce its surface tension, and then a magnetic field was applied to the water droplets on the superhydrophobic silica surface. It was found the contact angle of a water drops decreases with increasing magnetic field strength. When the magnetic field strength was adjusted in the range of 1-5T, the contact angle of the water drops varied from 94.2° to 140.6°. When the magnetic field was turned off, the contact angle of the droplets gradually restored, but did not completely return to the initial state. It is shown that the applied magnetic field has an important effect on the wettability of water droplets, and it is an effective way to regulate the reversible change of droplet wettability.