Locomotion of magnetoelastic membranes in viscous fluids

The development of multifunctional and biocompatible microrobots for biomedical applications relies on achieving controllable locomotion. Here we describe the conditions that allow homogeneous magnetoelastic membranes composed of superparamagnetic particles to swim through viscous fluids. By solving the equations of motion, we find the dynamical modes of circular membranes in precessing magnetic fields, which are found to actuate in or out of synchronization with a magnetic field precessing above or below a critical precession frequency ωc, respectively. For frequencies larger than ωc, synchronized transverse waves propagate on the membrane along the rotational (perimeter) and radial directions. Using the lattice Boltzmann approach, we show how these waves give rise to locomotion in an incompressible fluid at low Reynolds numbers. Nonreciprocal motion resulting in swimming is achieved by breaking the morphological symmetry of the membrane, attained via truncation of a circular segment. The membrane translation can be adapted to a predetermined path by programming the external magnetic field. Our results lay the foundation for achieving directed motion in thin, homogeneous magnetoelastic membranes with a diverse array of geometries.