*3.2.3 Emulsion-coacervation method*

Like the methods described in Sections 3.2.1 and 3.2.2, the emulsion-coacervation method uses the emulsion as a template, the difference is that the formation and stabilization of the polymer shell can be achieved by physical coacervation, chemical crosslinking, photopolymerization, sonochemical techniques, *in situ* polymerization, atom transfer radical polymerization (ATRP), and addition-fragmentation chain

transfer (RAFT) [5, 33, 34]. Therefore, the materials commonly used for the fabrication of nanocapsules are usually monomers, polymers possessing cross-linking function groups or polyelectrolytes [35]. The general procedure involves the formation of the nanoemulsion firstly, coacervation phase stabilization, and finally, monomer/ polymer crosslinking. Thus, some factors that are also necessary for the fabrication of nanocapsules by the emulsion-coacervation method include the addition of coacervation or crosslinking agents and the modification of certain variables, such as pH and temperature [36]. The main advantage of this method is that it permits to obtain a rigid nanocapsule shell structure, which can help to minimize the leakage of the payloads to the external phase. However, the final product may contain monomer residues that did not react [33].
