Bioinspired multi-asymmetric magnetized surfaces for tailored liquid operations and 3-DOF solid transport

Through the utilization of smart materials and well-designed structures, functional surfaces have been developed to enable small-scale liquid/solid manipulation tasks, thereby facilitating crucial applications in the fields of microfluidics, soft robotics, and biomedical engineering . However, the design of functional systems with flexible, tunable, and multimodal liquid/solid manipulation capabilities remains a challenging endeavor. Here, inspired by asymmetric structural features in natural plants and metachrony in cross-scale biological systems, I report a magnetic-responsive functional surface that can achieve rich liquid operations under static magnetic fields , while also enabling the transportation of solids with multiple degrees of freedom (DOFs) under dynamic magnetic fields . The presence of curvature pillars on the surface, combined with their magnetic-driven tilt/gradient arrangement, imparts liquids with multi-directional spreading modes based on the asymmetry of Laplace pressure . I elucidate the mechanisms governing these liquid spreading modes and subsequently develop compelling liquid operations, such as adjustable anti-gravity climbing, spontaneous modal shifts in liquid transport, and liquid mixing. Furthermore, the dynamic metachronal motion of the magnetic pillars can be harnessed for solid object transportation. I illustrate the synchronous/asynchronous transport modes of the surface and propose a novel strategy for achieving 3-DOF solid transportation by coordinating the arrangement of objects and employing magnetic actuation strategies. This study presents a new design concept for application-oriented manipulation surfaces, which hold significant potential for extensive engineering applications .