Contractile actuation and dynamical gel assembly of paramagnetic filaments in fast precessing fields

TL;DR

This paper investigates how flexible superparamagnetic filaments respond to fast precessing magnetic fields, enabling controllable actuation and dynamic assembly of gel-like structures with potential applications in microscopic manipulation.

Contribution

It introduces a method to control filament forces and assembly via magnetic field parameters, including precession frequency and angle, for designing dynamic, self-healing gels.

Findings

Filaments exert controllable tensile forces along the precession axis.

Rapid assembly of filament configurations with tunable material properties.

Design of a magnetic field to dynamically assemble a self-healing gel.

Abstract

Flexible superparamagnetic filaments are studied under the influence of fast precessing magnetic fields using simulations and a continuum approximation analysis. We find that individual filaments can be made to exert controllable tensile forces along the precession axis. These forces are exploited for microscopic actuation. In bulk, the filaments can be rapidly assembled into different configurations whose material properties depend on the field parameters. The precession frequency affects filament aggregation and conformation by changing the net torques on the filament ends. Using a time-dependent precession angle allows considerable freedom in choosing properties for filament aggregates. As an example, we design a field that twists chains together to dynamically assemble a self-healing gel.