What is it about?
We show a method to compute in a very precise form the depletion interaction in a simulation of a bidisperse or, in general, polydisperse colloidal solution. The method is quite simple, and it may be even applicable to experiments, using confocal images. The measured forces are the effective ones acting on a given class of colloids, after other classes have been traced out, and are temperature and density dependant.
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Photo by Bilal O. on Unsplash
Why is it important?
Depletion interactions are present in all mixtures of colloids with different sizes, but up to now their measurement in experiments and simulations has been only approximated. With this method we get basically the exact depletion forces acting beteen pairs of colloids in one size class, improving over the common approach of using the mean potential.
Perspectives
We hope researchers will pick up this method for the charcterization of depletion forces in different colloidal systems. One fascinating question still remains: since this method leaves as a by-product a numerical noise that can be stored and analyzed, may it be possible to use this noise to generate the dynamics of the colloidal class of interest, using some type of Langevin equatiion?
Gabriel Perez-Angel
Centro de Investigación y de Estudios Avanzados del IPN
Read the Original
This page is a summary of: Determining depletion interactions by contracting forces, The Journal of Chemical Physics, August 2022, American Institute of Physics,
DOI: 10.1063/5.0099919.
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