Ultra-flexible magneto-elastic diaphragm for low-power actuation applications

The demand for low-power flexible actuators is growing in various fields, including soft robotics, biomedical implants, and laboratory-on-a-chip systems. Conventional actuators such as motors, piezoelectric stacks, and pneumatic networks often suffer from limitations including rigidity, high-voltage requirements, or bulky components. Magnetic elastomer composites offer a promising alternative, enabling wireless and reversible actuation. However, most reported devices require high magnetic fields (more than 50 mT) or thick membranes to achieve even modest displacements. Here, we introduce the design and experimental validation of an ultra-flexible magneto-elastic diaphragm that achieves millimeter-scale deflection under low magnetic fields. This diaphragm is made from Ecoflex 00-20 elastomer embedded with NdFeB microparticles and is fabricated using a molding process. Custom 3D-printed molds produced concentric membrane folds while ensuring a uniform thickness of ∼300 μm. Vibrating sample magnetometry confirmed stable magnetic properties, while finite element modeling predicted large out-of-plane deformation under modest loads. Electromagnetic actuation was achieved using a compact 600-turn coil. At a field of 19 mT applied from a separation distance of 5 mm, the diaphragm exhibited a maximum central deflection of 5.6 mm. The structure maintained stable performance at excitation frequencies ranging from 1 to 5 Hz and did not exhibit degradation for more than 5000 actuation cycles. These results establish the diaphragm as a low-energy, compact actuation platform that outperforms previously reported magnetic composites in both displacement and efficiency. The combination of a thin, compliant geometry and strong magnetic responsiveness makes it highly suitable for integration into next-generation micropumps, wearable haptic interfaces, and implantable biomedical devices.