Electrohydrodynamic instabilities in thin liquid trilayer films

Scott A. Roberts, Satish Kumar

Research output: Contribution to journalArticlepeer-review

41 Scopus citations

Abstract

Experiments by Dickey et al. [Langmuir22, 4315 (2006)] and Leach et al. [Chaos15, 047506 (2005)] show that novel pillar shapes can be generated from electrohydrodynamic instabilities at the interfaces of thin polymer/polymer/air trilayer films. In this paper, we use linear stability analysis to investigate the effect of free charge and ac electric fields on the stability of trilayer systems. Our work is also motivated by our recent theoretical study [S. A. Roberts and S. Kumar, J. Fluid Mech.631, 255 (2009)] which demonstrates how ac electric fields can be used to increase control over the pillar formation process in thin liquid bilayer films. For perfect dielectric films, the effect of an ac electric field can be understood by considering an equivalent dc field. Leaky dielectric films yield pillar configurations that are drastically different from perfect dielectric films, and ac fields can be used to control the location of free charge within the trilayer system. This can alter the pillar instability modes and generate smaller diameter pillars when conductivities are mismatched. The results presented here may be of interest for the creation of complex topographical patterns on polymer coatings and in microelectronics.

Original languageEnglish (US)
Article number122102
JournalPhysics of Fluids
Volume22
Issue number12
DOIs
StatePublished - Dec 14 2010

Bibliographical note

Funding Information:
Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under Contract No. DE-AC04-94AL85000.

Funding Information:
This material is based upon work supported by the Department of Energy under Award No. DE-FG02-07ER46415. We are grateful for resources from the University of Minnesota Supercomputing Institute. S.A.R. acknowledges the support from a Doctoral Dissertation Fellowship from the Graduate School of the University of Minnesota.

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