Microemulsions are spontaneously formed systems and exhibit
nano-dispersed structures[59]. Microemulsions have special fea-tures, such as: thermodynamically stable[60], large interfacial area,
ultralow interfacial tension and optical transparency[59].The Gibbs
free energy of the microemulsions is negative or zero (ΔGfr0). The
size of the drops in microemulsions is much smaller than for
emulsions. Researchers as Ramadhas[61] and Rao[62] indicated
that generally they are in the range of 0.001–0.15mm. This corre-sponds with Ochoterena et al.[55]who reported the range size of
the drops in microemulsions to be of the order of 0.005–0.02mm.