Locomotion of magnetoelastic membranes in viscous fluids

TL;DR

This paper presents a theoretical and computational framework for magnetoelastic membranes swimming in viscous fluids, demonstrating how magnetic actuation and membrane shape control enable directed locomotion at low Reynolds number.

Contribution

It introduces a novel approach to induce and control locomotion in magnetoelastic membranes using magnetic fields and shape modifications, advancing microrobotics for biomedical applications.

Findings

Membranes exhibit synchronized and out-of-sync dynamical modes depending on magnetic precession frequency.

Locomotion is achieved through non-reciprocal shape changes breaking symmetry.

Magnetic fields can program membranes to follow predetermined paths.

Abstract

The development of multifunctional and biocompatible microrobots for biomedical applications relies on achieving locomotion through viscous fluids. Here, we describe a framework for swimming in homogeneous magnetoelastic membranes composed of superparamagnetic particles. 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, $\omega_c$, respectively. For frequencies larger than $\omega_c$, synchronized rotational and radial waves propagate on the membrane. These waves give rise to locomotion in an incompressible fluid at low Reynolds number using the lattice Boltzmann approach. Non-reciprocal 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.