Electrostatic bottom-driven rotary stage on multiple conductive liquid-ring bearings

We present a 2 cm-diameter rotary stage electrostatically actuated by ~15 V
_DC
. Multiple rings of an ionic liquid are used as both low-friction mechanical bearings and electric connections between the rotor and the substrate. The ring-bearing device is the first that was successfully rotated by electrostatic forces among the recent rotary devices involving a liquid bearing. Compared with the recent side-driven counterpart, the bottom-driven device of this report not only reduces the actuation voltage but also enables a reliable capacitive position sensing.