Magnetically reconfigurable rectifiers for versatile 3D liquid manipulation

Manipulating small-volume liquids is crucial in nature and industry. However, current liquid manipulation technologies often need complex energy inputs or fixed surfaces, limiting their real-world applications. Here, we introduce a simple and adjustable three-dimensional (3D) liquid manipulation paradigm that controls liquid behaviors by coupling interfacial energy with programmable static magnetic fields. This paradigm centers around a hierarchical rectifier with magnetized microratchets, enabling multimodal directional control of small-volume liquids. Under pre-programmed magnetic fields, the rectifier can reconfigure its morphology and harness interfacial energy to support rich liquid behaviors without dynamic real-time control. Switchable reconfigurations show improved rectification performance, offer flexible transport direction control, and promote spatiotemporally controllable inchworm-like 3D liquid manipulation, which may promote versatile engineering and biochemistry applications.