Compound micromachines powered by acoustic streaming

This paper presents the design, fabrication, and operation of compound micromachines powered by acoustic streaming. The machine components were directly incorporated around pillars serving as shafts without further assembly steps using a single-step in situ polymerization process controlled by a programmable projector. Two strategies were presented for harvesting acoustic energy using sharp-edged structures. The first method is based on on-board pumping of fluids and the second method involves engineering of rotors. The implementation of these strategies resulted in the construction of microscale turbines and engines that can be coupled to gear trains for adaptable transmission of mechanical power. We provide a number of further improvements that may together lead to development of compact yet powerful robotic manipulation systems inside microfluidic devices.