Theory of simultaneous control of orientation and translational motion of nanorods using positive dielectrophoretic forces

The manipulation of individual submicron-sized objects has been the focus of significant efforts over the last few years. A method to arbitrarily move and orient a set of rod-shaped conductive particles in a region defined by a set of electrodes using positive dielectrophoretic forces is presented. While the orientation of each particle is directly specified through the angle of the local electric field, its position is indirectly controlled through the applied force. Each electrode is approximated as an unknown point charge and an induced dipole. Since each induced dipole results from the combination of all other sources, a set of linear constraints are derived to enforce the self-consistency of the system. Additionally, the force and orientation of each particle also form an additional set of linear constraints. This combined set of constraints is then solved numerically to yield the sources required to induce the desired orientation and motion of each particle. It is observed that the minimum number of electrodes that can be used to control a set of N particles is 4N+1. Numerical simulations demonstrate that the control of a single nanorod (diameter of 70 nm; length of 1.4μm) in the midst of a realistic electrode array can be accomplished under practical conditions. In addition, such control of orientation and motion can be achieved over an ample region in the vicinity of each rod. Comments Copyright 2005 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. Reprinted in Journal of Applied Physics, Volume 98, Issue 12, Article 124314, December 30, 2005, 7 pages. Publisher URL: http://dx.doi.org/10.1063/1.2148627 This journal article is available at ScholarlyCommons: http://repository.upenn.edu/ese_papers/265 Theory of simultaneous control of orientation and translational motion of nanorods using positive dielectrophoretic forces Brian Edwards and Nader Engheta Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104 Stephane Evoy Department of Electrical and Computer Engineering and National Institute for Nanotechnology, University of Alberta, Edmonton AB T6G 2V4, Canada Received 1 June 2005; accepted 9 November 2005; published online 30 December 2005 The manipulation of individual submicron-sized objects has been the focus of significant efforts over the last few years. A method to arbitrarily move and orient a set of rod-shaped conductive particles in a region defined by a set of electrodes using positive dielectrophoretic forces is presented. While the orientation of each particle is directly specified through the angle of the local electric field, its position is indirectly controlled through the applied force. Each electrode is approximated as an unknown point charge and an induced dipole. Since each induced dipole results from the combination of all other sources, a set of linear constraints are derived to enforce the self-consistency of the system. Additionally, the force and orientation of each particle also form an additional set of linear constraints. This combined set of constraints is then solved numerically to yield the sources required to induce the desired orientation and motion of each particle. It is observed that the minimum number of electrodes that can be used to control a set of N particles is 4N+1. Numerical simulations demonstrate that the control of a single nanorod diameter of 70 nm; length of 1.4 m in the midst of a realistic electrode array can be accomplished under practical conditions. In addition, such control of orientation and motion can be achieved over an ample region in the vicinity of each rod. © 2005 American Institute of Physics. DOI: 10.1063/1.2148627