Small angle and quasi-elastic neutron scattering studies on polymethylmethacrylate latices in nonpolar media

Poly(methylmethacrylate) particles stabilised by poly(12-hydroxystearic acid) in a hydrocarbon medium provide, as a polymer latex, a useful system for investigating the properties of a sterically stabilised concentrated dispersion. In the present work these latices were investigated by small angle coherent neutron scattering and by quasielastic incoherent scattering. The former technique was used to probe the dimensions of the surface layer of poly(12-hydroxystearic acid) and to determine the diameter of the core particle of poly(methylmethacrylate) using dilute dispersions. In concentrated dispersions it was used to determine the structure factor. The latter was compared with that expected for an interacting system of hard spheres and reasonable agreement obtained. The quasielastic technique was used to probe the translational diffusion of the poly(12-hydroxystearic acid) molecules on the surface and the diffusion of the total particles in the concentrated systems.