Interfacial structure and wetting behavior of water droplets on graphene under a static magnetic field

The effect of an external static magnetic field on the wetting behavior of graphene has been investigated using molecular dynamics simulation in an isothermal-isochoric ensemble. The contact angle is evaluated firstly as a function of magnetic field for water droplet on hydrophobic graphene ribbon. In addition, the density and hydrogen bonding profiles along the direction perpendicular to the graphene surface are also reported. Results demonstrate that water at ambient temperature is expelled from the interfacial region upon applying relatively low magnetic field below 0.5 T, and attracted back with further increase in field intensity. The magnetic-field-induced desorption and adsorption of graphene is firstly achieved theoretically. Moreover, the variation of the first peaks in water density and H-Bond profiles reflects that the interfacial water on graphene surface can respond to magnetic field even in the first layer. Meanwhile, the contact angle of graphene ribbon varies inversely with the density and H-Bond number of interfacial water. This research could shed light on the mechanism of magnetic dewetting of hydrophobic surface, and provide a possibility to control the wettability of graphene by magnetic field.