Scientists from North Carolina State University have developed a method of getting soft robotic objects to move using directed magnetic fields. They say that it could be used for applications ranging from remotely-triggered drug-delivery pumps within the body, to the development of remotely deployable structures.

The researchers started by adding iron microparticles to a liquid polymer, then applying a magnetic field to the mixture. This induced the iron particles to arrange themselves into parallel chains. The liquid was then left to dry, forming into an elastic polymer thin film, with the chains of iron particles embedded within it.

When that film was subsequently subjected to magnetic fields, the iron particle chains would try to align themselves with it, moving the film with them. By varying the strength and direction of the magnetic field, it was possible to get the material to move in different ways.

Using this technique, the scientists created three types of soft "robots." One is a cantilever that can lift up to 50 times its own weight, another is an accordion-like device that expands and contracts like a muscle, and the third is a tube that functions as a peristaltic pump.

"We're now working to improve both the control and the power of these devices, to advance the potential of soft robotics," says associate professor Joe Tracy.

A paper on the research was recently published in the journal ACS Applied Materials & Interfaces.