In binary colloidal mixtures, depletion forces of purely entropic origin play an important role besides interaction like Coulomb or van der Waals interactions. We have measured the potential energy between a single, negatively charged polystyrene sphere (R = 1.5 μm) close to an equally charged wall in the presence of uncharged polymer coils (r = 150 nm) by means of total internal reflection microscopy. Our results show a strong dependence on the polymer concentration n and can be explained by the occurrence of depletion forces. Comparison of our data with a theory which is only correct in first-order n shows good agreement. We also present first observations in a system with an increased particle/polymer size ratio (R = 5 μm, r = 0.15 μm) where higher-order terms in the depletion potential become important. © Springer-Verlag 1999.
CITATION STYLE
Rudhardt, D., Bechinger, C., & Leiderer, P. (1999). Entropic interactions in mixtures of colloids and non-ionic polymers. Progress in Colloid and Polymer Science, 112, 163–167. https://doi.org/10.1007/3-540-48953-3_34
Mendeley helps you to discover research relevant for your work.