The Effect of Neutral Polymer and Nonionic Surfactant Adsorption on the Electroacoustic Signals of Colloidal Silica

The Effect of an Absorbed Polyelectrolyte Layer on the Dynamic Mobility of a Colloidal Particle

“…This problem has already been studied by Carasso et al [3]. The only point in considering it here is to verify that the new formulation (7.5) yields the same result as that obtained by Carasso.…”

“…It is the same as the equation of motion derived by Carasso et al [3], but it has an added term 1 p E s , where 1 p is the polymer charge density. The first term on the left-hand side of this equation is the net elastic force due to deformation of the polymer; g is the shear modulus of the polymer, y is distance from the particle surface and V is the local polymer velocity.…”

“…In their electroacoustic study of nonionic polymer layers, Carasso et al [3] devised a method for measuring the surface mobility factor M. This method can also be applied to charged polymer layers. The first step involves the measurement of the dynamic mobility spectrum for the uncoated colloid.…”

“…The final term on the left-hand side of (5.1) is the drag force of the liquid on the polymer. Here u is the liquid velocity and a is the polymer drag coefficient, a quantity that increases as the polyelectrolyte layer becomes more compact (see Appendix A of [3]). The equation of motion for the liquid has a similar form, viz h @ 2 u @y 2 p e E s a V À u 0:…”

“…This ESA spectrum depends on the structure of the polyelectrolyte coating. In their ESA study of nonionic polymer layers on colloidal particles, Carasso et al [3] developed a theory for the change in the ESA spectrum due to polymer addition. They used this theory to determine the thickness, elasticity and porous drag coefficient for various polymer layers from their ESA measurements The aim of this paper is to extend Carasso's approach to charged polymer layers.…”