Depletion forces in bulk and in confined domains: From Asakura–Oosawa to recent statistical physics advances

• Interaction between colloidal particles
• Depletion forces
• Asakura–Oosawa formula as a special case
• Ornstein–Zernike relation
• Computer simulation of depletion forces

This article summarizes recent theoretical research concerned understanding depletion forces. These forces appear when small colloidal particles, polymers or other entities, usually called depletants, are driven out from the gap or film between two macroparticles. Applying the modern tools of statistical mechanics and in agreement with experimental measurements it is shown that depletion attraction is only a part of more general medium-mediated interaction forces in colloidal dispersions known as structural forces. Finally, it highlights the important role that long-range structural forces could play in various applications relying on effecting particle dispersion, foam and emulsion stability, as well as wetting behavior of colloidal fluids on solid.

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