Statics and dynamics of magnetocapillary bonds

TL;DR

This paper investigates the dynamic behavior of magnetocapillary bonds formed by ferromagnetic particles at interfaces, revealing deformation modes, resonances, and potential for non-reciprocal motion, advancing understanding of controllable self-assemblies.

Contribution

It introduces a dynamic analysis of magnetocapillary bonds, identifying deformation modes and resonances, and proposes a model for collective behaviors.

Findings

Identified two deformation modes of magnetocapillary bonds.

Discovered resonance frequencies that enable non-reciprocal motion.

Proposed a model for collective behaviors based on bond dynamics.

Abstract

When ferromagnetic particles are suspended at an interface under magnetic fields, dipole-dipole interactions compete with capillary attraction. This combination of forces has recently given promising results towards controllable self-assemblies, as well as low Reynolds swimming systems. The elementary unit of these assemblies is a pair of particles. Although equilibrium properties of this interaction are well described, dynamics remain unclear. In this letter, the properties of magnetocapillary bonds are determined by probing them with magnetic perturbations. Two deformation modes are evidenced and discussed. These modes exhibit resonances whose frequencies can be detuned to generate non-reciprocal motion. A model is proposed which can become the basis for elaborate collective behaviours.