In the second experiment (10% of methyl oleate), less than 10%
of the formed droplets had a size of the order of 0.8 lm. About 50%
of droplets had a size lower or equal to 1.5 lmand 10% had a diameter
superior to 3.5 lm. After a month of ageing, the drops average
size was about 4.6 lm, with a maximal size around 9.2 lm for 10%
of droplets and a minimal size of 3 lm. The droplets size also tripled
during the storage.
Such a diameter increase may be due to flocculation or to coalescence.
In the first case, it would mean that the emulsion degradation
is reversible, and that after a certain excitement the
emulsion would take back the initial droplets size distribution. In
the second case, the degradation is irreversible and it would be
necessary to re-emulsify the mixture. Microscopy observations
(Supplementary data S4) showed that the size of the primary droplets
did not increase, whereas aggregates are getting larger after
1 month. Flocculation is thus the driving mechanism for emulsion
destabilization in our systems.