Microemulsion Polymerization. 1. Small-Angle Neutron Scattering Study of Monomer Partitioning

To achieve a better understanding of the kinetics of microemulsion polymerization, we have examined monomer partitioning between micelles and polymer particles during polymerization of aqueous microemulsions of dodecyltrimethylammonium bromide surfactant and styrene, n -butyl methacrylate, tert -butyl methacrylate, and n -hexyl methacrylate monomers. Polymerizing microemulsions are simulated by equilibrium mixtures of unpolymerized and fully polymerized microemulsions for which the monomer partitioning is accurately measured using small-angle neutron scattering. Experimental results are semiquantitatively reproduced by modeling the monomer partitioning as a competition between the Flory−Huggins bulk polymer free energy and the Helfrich curvature elastic energy of the surfactant monolayers.