Article abstract
Nature Materials 6, 235 - 240 (2007)
doi:10.1038/nmat1843
Subject Categories: Electronic materials | Semiconductors | Separation materials
Remotely powered self-propelling particles and micropumps based on miniature diodes
Suk Tai Chang1, Vesselin N. Paunov2, Dimiter N. Petsev3 and Orlin D. Velev1
Abstract
Microsensors and micromachines that are capable of self-propulsion through fluids could revolutionize many aspects of technology. Few principles to propel such devices and supply them with energy are known. Here, we show that various types of miniature semiconductor diodes floating in water act as self-propelling particles when powered by an external alternating electric field. The millimetre-sized diodes rectify the voltage induced between their electrodes. The resulting particle-localized electro-osmotic flow propels them in the direction of either the cathode or the anode, depending on their surface charge. These rudimentary self-propelling devices can emit light or respond to light and could be controlled by internal logic. Diodes embedded in the walls of microfluidic channels provide locally distributed pumping or mixing functions powered by a global external field. The combined application of a.c. and d.c. fields in such devices allows decoupling of the velocity of the particles and the liquid and could be used for on-chip separations.
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, USA
- Surfactant & Colloid Group, Department of Chemistry, University of Hull, Hull HU6 7RX, UK
- Department of Chemical and Nuclear Engineering and Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131, USA
Correspondence to: Orlin D. Velev1 e-mail: odvelev@unity.ncsu.edu
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