Clustering of binary colloidal suspensions: Experiment

Direct Measurement of Depletion and Structural Forces in Polydisperse, Charged Systems

“…[11] and [12]). Two spherical particles of radius R are interacting across gap width h in a solution of spherical macromolecules of varying radius a and bulk concentration ρ b .…”

“…Finally, the particle-particle depletion interaction predicted with Eq. [12] was converted into a particle-plate interaction by simply multiplying by two, which is valid in the Derjaguin limit of R a eff and R h. For the experiments described here, the minimum value of R/a eff was 28 (assuming the effective thickness of the double layer surrounding the macromolecules was 5 Debye lengths), while the range of particle separations sampled (0-250 nm) was much smaller than the particle radius (1.75 µm).…”

“…Equation [12], which was developed for a distribution in macromolecule size, can also be applied to systems with a distribution in macromolecule surface potential. For this analysis, a i and a j are replaced by ψ i,0 and ψ j,0 , where ψ i,0 and ψ j,0 denote the macromolecule surface potentials.…”

“…This difference arises because the virial expansion used to predict the macromolecule density distribution in Eq. [12] was calculated only to second order in macromolecule concentration. At the relatively high macromolecule concentrations used in these experiments, it is likely that higher-order terms in the expansion are also important.…”

Interactions in Colloidal Mixtures: Partial Structure Factors in Mixtures of Colloidal Silica and an Anionic Oil-in-Water Microemulsion

“…There have added degree of flexibility is not found in other colloidal been many experimental studies of the equilibrium phase mixtures. One challenge is that kinetically stable solid disbehavior (1-6) and stability, (7)(8)(9)(10)(11) of colloidal mixtures. persions are sensitive to the nature of their chemical environOne underlying theme in the study of colloidal mixtures is ment, and this sensitivity to aggregation imposes severe conthe effect that any ''microstructure'' in the solvent has on straints on the formulation of a compatible microemulsion.…”