Origami NdFeB Flexible Magnetic Membranes with Enhanced Magnetism and Programmable Sequences of Polarities

Abstract

AbstractPermanent magnets are essential components for many biomedical systems and electromechanical devices, which may be made into flexible formats to achieve wearable monitoring and effective integration with biological tissues. However, the development of high‐performance flexible permanent magnets is challenging due to their ultrathin geometries, which contradict with the thickness‐dependent magnetic properties. In addition, magnetic membranes with controllable sequences of polarities are difficult to achieve. Here, origami techniques to achieve flexible permanent magnetic membranes with enhanced magnetic field strength and programmable sequences of polarities are presented. Linear Halbach arrays, circular Halbach arrays, and concentric magnets with thicknesses ranging from 130 to 500 µm and bending curvatures ranging from 0.039 to 0.0043 µm−1 are achieved through different folding mechanisms. The origami membranes offer a maximum field intensity of 72 mT and extremely strong magnetic force of 0.21 N cm−2, allowing various novel applications demonstrated through electronics interfacing, cell manipulations, and soft robotics. The origami techniques offer large magnetism and complex spatial field distribution, and enable practical use of thin flexible magnetic membranes in constructing miniaturized or even flexible electromechanical systems and biomedical instruments for magnetic resonance imaging, targeted drug delivery, health monitoring, and cancer therapy.