Electrostatic surface heterogeneity on the order of a few nanometers is common in colloidal and bacterial systems, dominating adhesion and aggregation and inducing deviations from classical DLVO theory based on a uniform distribution of surface charge. Topographical heterogeneity and roughness also strongly influence adhesion. In this work, a model is introduced to quantify the spatial fluctuat...

Theory is developed to address a significant problem of how two charged dielectric particles interact in the presence of a polarizable medium that is a dilute solution of a strong electrolyte. The electrostatic force is defined by characteristic parameters for the interacting particles (charge, radius, and dielectric constant) and for the medium (permittivity and Debye length), and is expressed...

This chapter describes the effect of pH-changes on the surface forces in thin, surfactant-free aqueous films containing a low background concentration of sodium chloride. Despite their exceedingly low surface elasticities, the surfactant-free aqueous films that have an equilibrium thickness about 100 nm are metastable for pH-values between 5 and 10. The extended DLVO theory was used to calculat...

In this work the colloid stability mechanisms of two sulfonated latexes prepared by different methods are studied. One of the latexes (JM1) was prepared by surfactant-free emulsion copolymerization of styrene (St) and sodiun styrene sulfonate (NaSS), while the second latex (SN9) was prepared by a twostage “shot-growth” emulsion polymerization process using NaSS as ionic comonomer, which is incl...

Dynamic light scattering and electrophoretic mobility measurements have been used to characterize the size, size distribution and zeta potentials (zeta-potentials) of egg yolk phosphatidylcholine (EYPC) liposomes in the presence of monovalent ions ( Na(+) and K(+)). To study the stability of liposomes the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory has been extended by introducing the hydrat...

The interparticle interactions in colloidal suspensions of charged disks of Laponite clay in water were investigated using dynamic light scattering (DLS) and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. We studied the effects of clay concentration (C(L)), the concentration of externally added salt (C(S)), and temperature (T) on the microscopic dynamics of the clay suspensions. The fast (τ1) ...

Foam systems have been attracting extensive attention due to their importance in a variety of applications, e.g., in the cleaning industry, and in bubble flotation. In the context of flotation chemistry, flotation performance is strongly affected by bubble coalescence, which in turn relies significantly on the surface forces upon the liquid film between bubbles. Conventionally, unusual short-ra...