Phase inversion emulsification technique is an effective physical method to prepare waterborne dispersions of polymeric resins In this study

a multi-hollow epoxy resin sphere was obtained by incompletephase inversion emulsification．The dynamic morphological evolution of water droplets dispersed in bisphenoL A epoxy resin／emulsifier (a multi-block copolymer)during phase inversion process was investigated with scanning electron microscopy．It is shown that small discrete water droplets are dispersed in the epoxy resin continuous phase at low water content. In this case．the dynamic coalescence among the small water droplets is ignored．With increasing water content

the dynamic coalescence becomesremarkable and larger water drops are formed by the coalescence among the small water droplets The larger water drops are randomly distributed within the continuous phase．Meanwhile

some necklace like structures with varied length co-exist with the small water droplets and larger water drops Incomplete phase inversion is achieved through the coalescence among the larger water drops

and some small water droplets are entrapped therein．In this caSe

a kind of multi-hoHow sphere is obtained．While．in some local regions

all the nearest small water droplets coalesce simultaneously to be continuous phase to achieve complete phase inversion

and small discrete waterborne particles are obtained The dynamic coalescence among the small water droplets dispersed in epoxy resin continuous phase could be analyzed in terms of theimproved Smoluchowski equation．