Control of colloids with gravity, temperature gradients, and electric fields

Matt Sullivan, Kun Zhao, Christopher Harrison, Robert H. Austin, Mischa Megens, Andrew Hollingsworth, William B. Russel, Zhengdong Cheng, Thomas Mason, P. M. Chaikin

Research output: Contribution to journalArticlepeer-review

62 Scopus citations


We have used a variety of different applied fields to control the density, growth, and structure of colloidal crystals. Gravity exerts a body force proportional to the buoyant mass and in equilibrium produces a height-dependent concentration profile. A similar body force can be obtained with electric fields on charged particles (electrophoresis), a temperature gradient on all particles, or an electric field gradient on uncharged particles (dielectrophoresis). The last is particularly interesting since its magnitude and sign can be changed by tuning the applied frequency. We study these effects in bulk (making 'dielectrophoretic bottles' or traps), to control concentration profiles during nucleation and growth and near surfaces. We also study control of non-spherical and optically anisotropic particles with the light field from laser tweezers.

Original languageEnglish (US)
Pages (from-to)S11-S18
JournalJournal of Physics Condensed Matter
Issue number1
StatePublished - Jan 15 2003

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Condensed Matter Physics


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