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IRTG / Soft Matter Science
Freiburger Materialforschungszentrum
Stefan-Meier-Str. 21
79104 Freiburg, Germany

Contact: Jana Husse

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softmattergraduate[at]uni-freiburg.de


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You are here: Home Events Prof. Michal Borkovec "Interparticle Forces in Aqueous Solutions"

Prof. Michal Borkovec "Interparticle Forces in Aqueous Solutions"

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Laboratory of Colloid and Surface Chemistry University of Geneva, Switzerland

What
  • Seminar
When Oct 18, 2017
from 02:15 PM to 03:00 PM
Where Seminarraum A, FMF, Stefan-Meier-Str. 21, Freiburg
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Many phenomena involving colloidal particles are governed by particle-particle or particle-substrate interactions. Examples include stability and rheology of colloidal suspensions, formation of colloidal crystals, or particle deposition. While the importance of such interaction forces has been appreciated for a long time, measuring such forces directly remained a considerable challenge until quite recently. Presently, however, various techniques are becoming available for direct force measurements, but the colloidal probe technique based on the atomic force microscope (AFM) seems to emerge as the most promising and versatile one.

The present talk will discuss the use of the colloidal probe technique to measure forces between colloidal particles. In particular, I will demonstrate that interactions between similar as well as dissimilar particles are principally controlled by electrostatic double-layer and van der Waals forces as described by the theory of Derjaguin, Landau, Verwey and Overbeek (DLVO). The talk will further highlight the nature of forces acting between charged colloidal particles in the presence of multivalent ions and polyelectrolytes. While forces in these systems remain DLVO-like and mainly controlled by charge reversal, additional attractive non-DLVO forces come into play. Two novel effects will be highlighted as well. First, charge regulation effects can become very important for dissimilar particles. Second, double layer forces can become strongly non-exponential in the presence of multivalent coions or like-charged polyelectrolytes.

I. Szilagyi, G. Trefalt, A. Tiraferri, M. Borkovec, Soft Matter 10 (2014) 2479-2502.
G. Trefalt, S. H. Behrens, M. Borkovec, Langmuir 32 (2016) 380-400.
M. Moazzami-Gudarzi, T. Kremer, V. Valmacco, P. Maroni, M. Borkovec, G. Trefalt, Phys. Rev. Lett. 117 (2016) 088001.

 

invited by Prof. Eckhard Bartsch

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