Acceleration of absolute negative mobility

Jan Regtmeier, Sebastian Grauwin, Ralf Eichhorn, Peter Reinmann, Dario Anselmetti, Alexandra Ros

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Recently, the counter intuitive migration phenomenon of absolute negative mobility (ANM) has been demonstrated to occur for colloidal particles in a suitably arranged post array within a microfluidic device [1]. This effect is based on the interplay of Brownian motion, nonlinear dynamics induced through microstructuring, and nonequilibrium driving, and results in a particle movement opposite to an applied static force. Simultaneously, the migration of a different particle species along the direction of the static force is possible [191, thus providing a new tool for particle sorting in microfluidic device format. The so far demonstrated maximum velocities for micrometer-sized spheres are slow, i.e., in the order of 10 nm per second. Here, we investigate numerically, how maximum ANM velocities can be significantly accelerated by a careful adjustment of the post size and shape. Based on this numerical analysis, a post design is developed and tested in a microfluidic device made of PDMS. The experiment reveals an order of magnitude increase in velocity.

Original languageEnglish (US)
Pages (from-to)1461-1467
Number of pages7
JournalJournal of Separation Science
Issue number10
StatePublished - Jul 2007
Externally publishedYes


  • Absolute negative mobility
  • Microfluidics
  • Separation

ASJC Scopus subject areas

  • Analytical Chemistry
  • Filtration and Separation


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