Université de Fribourg

Phase behaviour of colloids with short-range repulsions plus nonadsorbing polymer chains

Gruijthuijsen, Kitty van ; Tuinier, Remco ; Brader, Joseph M. ; Stradner, Anna

In: Soft Matter, 2014, vol. 9, no. 42, p. 9977–9982

The colloidal gas–liquid phase behaviour has been studied for aqueous mixtures of well-defined spherical particles with short-ranged repulsions mixed with relatively monodisperse poly(ethylene oxide) polymers. We show that our set of experimental phase diagrams are in quantitative agreement with theoretical predictions using generalized free volume theory [G. J. Fleer and R. Tuinier, Phys. Rev....

Université de Fribourg

Origin of suppressed demixing in casein/xanthan mixtures

Gruijthuijsen, Kitty van ; Herle, Vishweshwara ; Tuinier, Remco ; Schurtenberger, Peter ; Stradner, Anna

In: Soft Matter, 2012, vol. 8, no. 5, p. 1547-1555

We explore the properties of casein/xanthan mixtures for xanthan concentrations beyond those inducing phase separation. Previous work has successfully described the onset of demixing by depletion theory in the protein limit, where the xanthan polysaccharides , the polymers , are larger than the caseins from skim milk powder, the colloids (S. Bhat et al., J. Phys.: Condens. Matter, 2006, L339). We...

Université de Fribourg

A simple patchy colloid model for the phase behavior of lysozyme dispersions

Gögelein, Christoph ; Nägele, Gerhard ; Tuinier, Remco ; Gibaud, Thomas ; Stradner, Anna ; Schurtenberger, Peter

In: The Journal of Chemical Physics, 2008, vol. 129, no. 8, p. 085102

We propose a minimal model for spherical proteins with aeolotopic pair interactions to describe the equilibrium phase behavior of lysozyme. The repulsive screened Coulomb interactions between the particles are taken into account assuming that the net charges are smeared out homogeneously over the spherical protein surfaces. We incorporate attractive surface patches, with the interactions between...

Université de Fribourg

Spinodal decomposition in a food colloid–biopolymer mixture: evidence for a linear regime

Bhat, Suresh ; Tuinier, Remco ; Schurtenberger, Peter

In: Journal of Physics: Condensed Matter, 2006, vol. 18, p. L339–L346

We investigate phase separation and structural evolution in a complex food colloid (casein micelles) and biopolymer (xanthan) mixture using small-angle light scattering. We demonstrate that phase separation is induced by a depletion mechanism, and that the resulting coexistence curve can be described by osmotic equilibrium theory for mixtures of colloids and polymer chains in a background...