Amphibious Transport of Fluids and Solids by Soft Magnetic Carpets

TL;DR

This paper introduces soft magnetic carpets created via self-assembly that can amphibiously transport both liquids and solids, with tunable control and novel cargo reversal effects, advancing micromanipulation in robotics.

Contribution

The study presents a simple self-assembly method for magnetic carpets capable of amphibious transport and reveals new cargo reversal phenomena due to collective motion and elastohydrodynamics.

Findings

Carpets can transport liquids and solids larger than artificial cilia.

Transport is reconfigurable using simple micromagnets or programmable fields.

Identified and modeled cargo reversal effects due to collective ciliary motion.

Abstract

One of the major challenges in modern robotics is controlling micromanipulation by active and adaptive materials. In the respiratory system, such actuation enables pathogen clearance by means of motile cilia. While various types of artificial cilia have been engineered recently, they often involve complex manufacturing protocols and focus on transporting liquids only. Here, we create soft magnetic carpets via an easy self-assembly route based on the Rosensweig instability. These carpets can transport liquids but also solid objects that are larger and heavier than the artificial cilia, using a crowd-surfing effect. This amphibious transportation is locally and reconfigurably tuneable by simple micromagnets or advanced programmable magnetic fields with a high degree of spatial resolution. We identify and model two surprising cargo reversal effects due to collective ciliary motion and non-trivial elastohydrodynamics. While our active carpets are generally applicable to integrated control systems for transport, mixing and sorting, these effects could also be exploited for microfluidic viscosimetry and elastometry.