particle formation takes place these reactions appear to be occurring via a suspension polymerization process this terminology is normally associated with radical chain growth mechanism of polymerization where high molecular weight polymers are formed at a very early stage in the polymerization that is initiated with an oil soluble initiator this is compatible with the present case where the step growth thiol ene mechanism can occur inside the monomer droplet when initiated by the oil soluble initiator further evidence that these are suspension polymerizations comes from the fact that the size of the polymer particles decreases with increasing surfactant concentration and increasing homogenization energy in contrast emulsion polymerizations typically require water soluble initiators and typically need particle nucleation to occur when the growing polymer chain in the aqueous phases reaches a critical molecular weight and phase inversion because thiol ene polymerizations only achieve appreciable molecular weights at high conversions i e they are step growth polymerizations the latter phenomenon is not likely to occur in our systems conventional emulsion and micro emulsion polymerizations generally do not exhibit a dependence of particle size on homogenization energy in contrast to what we have seen here additionally the experiments shown here have a surfactant concentration above the critical micelle concentration u201c cmc u201d the cmc of sds is approximately 0 009 mole l 10 wt sds in water is 0 35 mole l and if emulsion polymerizations by micellar nucleation were occurring then the.