On the colloidal stability of polystyrene particles prepared with different kinds of surface active initiators

The stability of polystyrene latexes prepared with two different kinds of surface active initiators, poly(ethylene)glycol-sulfonate-azo-compounds and 2,2′-azobis(N-2-methylpropanoyl-2-amino-alkyl-1)sulfonate compounds, is investigated. Both types of initiators can be used in aqueous emulsion polymerizations as initiating and stabilizing systems. The experimentally observed stability during polymerization strongly depends on the poly(ethylene glycol) and alkyl chain length of both types of initiators. The calculated barrier height of the overall interaction energy between latex particles stabilized with either initiator end groups fits nicely with the experimentally observed stability during polymerization.