Characterizations and properties of hairy latex particles

Industrial latex composed of a hydrophobic core surrounded by a charged hydrophilic layer exhibits excellent stability toward monovalent salt. That feature is classically attributed to a steric effect due to a loss of entropy during overlapping of coating materials. The so-called electrosteric stabilization is, however, not a straightforward function of the nature of the hydrophilic corona. This suspension was characterized in dilute solution by scattering and electrophoresis techniques. In contrast to spherical brushes the interface between the core and the corona is not well defined. The layer is more similar to a highly hydrated nonuniform gel with few longer strands that control the hydrodynamic properties than to a polyelectrolyte brush whose dependence on ionic strength reflects the concentration of counterions inside a well-defined structure. Thus the steric contribution to stabilization of these hairy particles appears to be insignificant in the range studied. The highly hydrated nature and the global charge of the layer are two predominant factors for the stability of the particles.