Nonlinear electrokinetic transport and its applications under combined AC and DC fields in micro/nanofluidic interface devices

The integration of micro/nanofluidic devices led to many interesting phenomena and one of the most important and complex phenomenon among them is concentration polarization. In this thesis, we provide new physical insights in micro/nanofluidic interface devices on the application of AC and DC electric fields. By performing detailed numerical simulations based on coupled Poisson, Nernst−Planck, and incompressible Navier−Stokes equations, we discuss the electrokinetic transport and other hydrodynamic effects under the application of combined AC and DC electric fields for different nondimensional EDL thickness and nanochannel wall surface charge density. We understand that for a highly ion−selective nanochannel, the application of combined AC/DC electric field, at amplitudes greater than the DC voltage and at low Strouhal number, results in large dual concentration polarization regions (with unequal lengths) at both the micro/nanofluidic interfaces due to large and unequal voltage drops at these junctions. The highly nonlinear potential distribution gives rise to an electric field and body force that changes the electrokinetic fluid velocity from that obtained on the application of only a DC source. With the understanding of nonlinear electrokinetic transport under combined AC/DC fields, we propose a novel technique of increasing the product concentration of an enzymatic reaction inside the nanofluidic channel.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2012

Author dc:creator

• Nandigana, Vishal

Contributors dc:contributor

• Aluru, Narayana R.

• Concentration Polarization
• Nonlinear Electrokinetic transport
• Micro/Nanofluidic interface devices
• AC/DC electric fields
• Debye length
• space charge
• alternating current (AC)
• direct current (DC)

Statement dc:rights

• Copyright 2011 Vishal Venkata Raghave Nandigana

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/29477

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/29477