Nanocapsules were synthesized in O/W microemulsion by complex coacervation with natural polymer of arabic gum and gelatin. The synthesis conditions of polymeric nanocapsules were analyzed. Transmission electron microscopy (TEM) and photon correlation spectroscopy (PCS) show that sizes of nanocapsules are 30～100 nm with a narrow distribution. The effects of the composition of microemulsion, the concentration of polymer and the condition of complex coacervation on the characteristics of nanocapsules were investigated. The entrapment efficiency of cypermethrin in the nanocapsules manufactured was above 60%. This method is a novel approach to produce polymeric nanocapsules in mild condition.

Key words: microemulsion, complex coacervation, nanocapsule, templating synthesis, particle size