Recent advances in nano‐electromechanical and microfluidic power generation

Recent advances in nano-electromechanical systems and novel microfluidic devices to generate electricity are reviewed in this article. The primary driving mechanisms of each system are examined. Recent innovations include a nano-engine, which operates by transferring atoms between two molten metal droplets in a carbon nanotube. Another recent development includes a microchannel battery that produces electricity through the interaction of flowing water and the surfaces of many microchannels. The chemical reaction at the boundary between the water and microchannel surface leaves the walls negatively charged, thereby attracting positive ions from the fluid to harness an electrical current. Other recent advances in micro heat engine (MHE) fabrication are described in this article. Detailed focus is given to recent developments in MHEs, driven by thermocapillary forces. Thermocapillary pumping (TCP) of a discrete droplet in a microchannel converts heat input to droplet motion, then flexing of a piezoelectric membrane to generate electricity. The cyclic droplet motion expands and compresses the surrounding gas chambers in a closed-end microchannel. This paper reviews these and other recent advances in power generation for nano-electromechanical systems (NEMS) and micrelectromechanical systems (MEMS). Copyright © 2006 John Wiley & Sons, Ltd.