Structural, thermodynamic and light scattering properties of PMMA latex as a square well fluid in benzene

Abstract

Using the square well potential function as the basic description, various liquid state properties of polymethylmethacrylate (PMMA) dispersions in benzene were derived. The structure factors and reduced scattering intensities of these latex particles, predicted by this model, are compared with results obtained from light scattering experiments by Nieuwenhuis and Vrij. Fourier Transformation of structure factors were performed to obtain the radial distribution functions (RDF) and from these RDF's, co-ordination numbers of the latex particles were computed. The potential parameters fitted to generate the structure factors were also used to evaluate the long wave limit structure factor S(0) which, in turn, is used to obtain the diffusion coefficient of the latex at various concentrations. The present calculations clearly indicate some sort of ordering of the particles in dispersion. At all concentrations, the dispersion shows a close-packed structure. The results are in good agreement with previous experiments, showing that the square well potential is capable of explaining liquid state properties of the dispersed systems very well.