Heterocoagulation. Part 5.—Adsorption of a carboxylated polymer latex on monodispersed hydrated metal oxides

Abstract

The adsorption of a monodispersed polymer latex [poly(methyl methacrylate co-methacrylic acid)] with a radius of 40 nm on much larger spherical hydrated aluminium oxide and haematite particles of narrow size distribution was studied as a function of pH, temperature, ionic strength and particle number concentration. The thermodynamics and the kinetics of this heterosystem have been analysed taking the double layer properties of both types of particles into consideration. By measuring the adsorption isotherms of the latex on the (hydrated) metal oxide particles, it was possible directly to compare the experimentally determined interaction energies with the calculated values. The expression based on the classical theory of the electrical double layer greatly overestimates the electrostatic energy. However, the recently derived expression using the two-dimensional Poisson—Boltzmann equation is in excellent agreement with the experimental findings.