SURFACE-CHEMISTRY OF EMULSION POLYMERIZATION

The emulsion polymerization of styrene has been studied using several surface chemical techniques. Evidence has been obtained from dye adsor ption, latex morphology, and microelectrophoresis studies, which indic ate that two quite different mechanisms can operate, depending on the process conditions. Use of a water-insoluble initiator appears to favo r micellar nucleation, whereas persulfate initiator tends to produce l atex via homogeneous nucleation in the aqueous phase. An atomic force microscope adapted to measure surface forces was used to study the int eractions between polystyrene in water and surfactant solutions. The s trong hydrophobic attraction observed presents a likely explanation fo r the buildup of latex particles in the homogeneous nucleation process .