At microscopic scales, picking, placing, collecting, and arranging objects is a persistent challenge. Advances in nanotechnology mean that there are ever more complex things we’d like to build at those sizes, but tools for moving their component parts are lacking.
New research from the School of Engineering and Applied Science shows how simple, microscopic robots, remotely driven by magnetic fields, can use capillary forces to manipulate objects floating at an oil-water interface. This system was demonstrated in a study published in the journal Applied Physics Letters.
The study was led by Kathleen Stebe, Richer & Elizabeth Goodwin Professor in Penn Engineering’s Department of Chemical and Biomolecular Engineering, and Tianyi Yao, a graduate student in her lab. Nicholas Chisholm, a postdoctoral researcher in Stebe’s lab, and Edward Steager, a research scientist in Penn Engineering’s GRASP lab contributed to the research.
The microrobots in the Penn team’s study are thin slices of magnet, about a third of a millimeter in diameter. Despite having no moving parts or sensors of their own, the researchers refer to them as robots because of their ability to pick and place arbitrary objects that are even smaller than they are.
That ability is a function of the specialized environment where these microrobots work: at the interface between two liquids. In this study, the interface is between water and hexadecane, a common oil. Once there, the robots deform the shape of that interface, essentially surrounding themselves with an invisible “force field” of capillary interactions.
Read more at Penn Engineering.
