N Kumari et al 2008 J. Micromech. Microeng. 18 085018 doi:10.1088/0960-1317/18/8/085018
N Kumari, V Bahadur and S V Garimella
Show affiliationsElectrical actuation of liquid droplets at the microscale offers promising applications in the fields of microfluidics and lab-on-a-chip devices. Much prior research has targeted the electrical actuation of electrically conducting liquid droplets; however, the actuation of dielectric droplets has remained relatively unexplored, despite the advantages associated with the use of a dielectric droplet. This paper presents modeling and experimental results on the electrical actuation of dielectric droplets between two flat plates. A first-order analytical model, based on the energy-minimization principle, is developed to estimate the electrical actuation force on a dielectric droplet as it moves between two flat plates. Two versions of this analytical model are benchmarked for their suitability and accuracy against a detailed numerical model. The actuation force prediction is then combined with available semi-analytical expressions for predicting the forces opposing droplet motion to develop a model that predicts transient droplet motion under electrical actuation. Electrical actuation of dielectric droplets is experimentally demonstrated by moving transformer oil droplets between two flat plates under the influence of an actuation voltage. Droplet velocities and their dependence on the plate spacing and the applied voltage are experimentally measured and showed reasonable agreement with predictions from the models developed.
77.22.Ch Permittivity (dielectric function)
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
85.50.-n Dielectric, ferroelectric, and piezoelectric devices
Soft matter, liquids and polymers
Condensed matter: electrical, magnetic and optical
Issue 8 (August 2008)
Received 29 February 2008, in final form 9 June 2008
Published 24 July 2008
N Kumari et al 2008 J. Micromech. Microeng. 18 085018
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