am7b01209_si_001.pdf (618.28 kB)
Chained Iron Microparticles for Directionally Controlled Actuation of Soft Robots
journal contribution
posted on 2017-03-27, 20:32 authored by Marissa
M. Schmauch, Sumeet R. Mishra, Benjamin A. Evans, Orlin D. Velev, Joseph B. TracyMagnetic field-directed self-assembly
of magnetic particles in
chains is useful for developing directionally responsive materials
for applications in soft robotics. Using materials with greater complexity
allows advanced functions, while still using simple device architectures.
Elastomer films containing chained magnetic microparticles were prepared
through solvent casting and formed into magnetically actuated lifters,
accordions, valves, and pumps. Chaining both enhances actuation and
imparts a directional response. Cantilevers used as lifters were able
to lift up to 50 times the mass of the polymer film. We introduce
the “specific torque”, the torque per field per mass
of magnetic particles, as a figure of merit for assessing and comparing
the performance of lifters and related devices. Devices in this work
generated specific torques of 68 Nm/kgT, which is significantly higher
than in previously reported actuators. Applying magnetic fields to
folded accordion structures caused extension and compression, depending
on the accordion’s orientation. In peristaltic pumps comprised
of composite tubes containing embedded chains, magnetic fields caused
a section of the tube to pinch closed where the field was applied.
These results will facilitate both the further development of soft
robots based on chained magnetic particles and efforts to engineer
materials with higher specific torque.