Soft robots can now rotate and change shape using simple chemical reactions as their only motor.
April 24, 2026
Original Paper
Deformable and rotating soft actuators based on chemical magnets
SSRN · 6635184
The Takeaway
Soft actuators move and deform using chemical magnetism generated by redox reactions on a bimetallic surface. By placing these materials in a magnetic field, the internal chemical reaction creates Lorentz forces that push the material into a spin or a bend. This removes the need for bulky batteries, wires, or external motors to create movement in soft machines. The chemical fuel acts as both the power source and the controller for the robot motion. This technology could lead to tiny, autonomous medical robots that swim through the bloodstream powered only by the body's own chemistry.
From the abstract
If redox reactions occur on the surface of a bimetallic soft actuator, creating a current loop, a force will act on it in a nonuniform magnetic field. This force is essentially the Lorentz force. Here, we demonstrate various methods for controlling the force of chemical magnetism by varying the actuator's surface area, the type and concentration of electrolyte, and the use of different metals. To estimate the force of chemical magnetism, we propose a method which is based on comparing the a