Tension and bending of the particle raft driven by a magnet

Abstract

The particle raft is a special soft material formed by depositing hydrophobic particles onto the water surface. This paper investigates the deformation of particle rafts under non-contact magnetic field forces. Using hydrophobic iron powder for the fabrication of particle rafts, the tensile and bending deformation of ferromagnetic particle rafts in a magnetic field is quantified for the first time. By designing experiments with two different directions of magnetic field, the corresponding deformation phenomena of the particle rafts at different distances of the magnetic field are thus obtained and their functional relationships are obtained by means of dimensional analysis. By analysing the magnetic field strength and the specific magnetisation of the iron powder during the experiments, the magnetic force is introduced into PFC3D to establish a numerical model considering the effect of the magnetic field force. These findings can deepen our understandings on the mechanical behaviors of soft materials in the magnetic field, and they can provide some inspirations for the design and fabrication of micro-devices for precision manipulation.