This research was conducted to clarify the membrane formation mechanism of crosslinked polyurea microcapsules by phase separation method, specially the role of polymeric surfactant of poly(ethylene-alt-maleic anhydride),(poly(E-MA))at the interface of O/W emulsion. Because of its toxicity, alternative chemicals should be chosen. This understanding may make possible to find the alternative chemicals. It was found that poly(E-MA)was necessary for the formation of crosslinked polyurea membrane. The addition of sodium dodecyl sulfate (SDS) prohibited the membrane formation reaction at the interface, even in the care of poly(E-MA) concentration enough for polymeric microcapsule formation. From the results in this study, poly(E-MA) as polymeric surfactant was found to be adsorbed on the interface of O/W emulsion and provide the reaction site for the membrane formation of polymeric microcapsules
