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"Magnetic marshmallows" for soft robotics: magneto-mechanical characterization and application in switchable adhesion
Maxime Bès1, Samuel Lamont2, Azadeh Dufour-Lamartinie1,2
1Laboratoire Sciences et Ingénierie de la Matière Molle, ESPCI Paris, PSL University, Sorbonne Université, CNRS, F-75005 Paris, France. artem.kovalenko@espci.fr.
Soft Matter
|March 28, 2025
Summary
We developed novel magnetic elastomer foams that can be compressed and expanded by magnetic fields. These compressible actuators show potential for switchable adhesion applications.
Area of Science:
- Materials Science
- Soft Robotics
- Polymer Science
Background:
- Soft magnetic composites offer programmable deformation for soft robotics and switchable surfaces.
- Incompressible soft actuators face challenges with shape changes during compression or elongation, limiting actuation modes.
- Bending and folding are preferred actuation modes for current soft actuators.
Purpose of the Study:
- To explore magnetic elastomer foams as compressible actuators with a low Poisson's ratio.
- To investigate the compression and shape change behavior of these novel magnetic foams.
- To develop a switchable adhesion structure utilizing these compressible magnetic actuators.
Main Methods:
- Fabrication of polydimethylsiloxane (PDMS) foams with open porosity using a sacrificial salt pellet template method.
- Incorporation of carbonyl iron particles into the PDMS foam matrix.
- Characterization of reversible compression under magnetic field gradients and development of an analytical model.
Main Results:
- The fabricated magnetic foams exhibit strong, reversible compression in response to magnetic field gradients.
- Stress accumulation along the field gradient direction and foam thickness significantly influence magnetic strain.
- A simple analytical model based on magnetic body force effectively explains the observed compression effects.
Conclusions:
- Magnetic elastomer foams with low Poisson's ratio are viable compressible actuators.
- The study elucidates the role of magnetic body forces and foam geometry in actuation.
- A novel switchable adhesion structure was successfully demonstrated using the magnetic foam actuator.
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