droplet size makes nano-emulsions break by the Ostwaldripening
mechanism [12–14] in time periods which pose a great
limitation for developing applications different than nanoparticle
preparation. In fact, only an extremely low solubility of the
dispersed phase, as presented by silicone oils, would give the
stability needed for most of the applications. In this context,
Mason research group has published several papers studying
nano-emulsions with silicone oils as dispersed phase, [15–17].
These nano-emulsions show great stability even for such a high
concentration that droplets are deformed to a foam-like structure
[3], but no applications have been yet developed for these nanoemulsions.
Due to the limitations in the stability of nano-emulsions, a
revision of the most recent literature results in few papers proposing
new applications, and in most of them, nano-emulsions
must be prepared shortly before their use.
With respect to agrochemical applications, in a recent
reference [18] nano-emulsions are proposed for solubilizing
water-insoluble pesticides, the classical potential application.
Nano-emulsions are formed before the application by dilution
of a concentrate containing oil, surfactant, the active and 50% of
water. It is claimed that the nano-emulsions obtained show good
stability, but the diameter increases about five times in 14 h,
from 40 to 200 nm. Therefore, application should be carried out
a few hours after preparation for obtaining the advantages
of small droplet size. In this paper, the preparation of nanoemulsions
is presented as a novelty when comparing with
commercial microemulsion formulations which also result by
dilution in nano-emulsions. This fact demonstrates that application
of nano-emulsions for solubilizing pesticides is not a
potential application but a commercial one.