This results in Ostwald ripening
of the Bi precipitates, which may become sufficiently brittle to be a reliability concern.
As a result, larger particles grow at the expense of smaller particles by exchanging molecules of oil through the aqueous solution; a process referred to as Ostwald ripening
can be reduced by adding oils of very low polarity to very polar oils.
The crystal grew under a process known as Ostwald ripening
O diametro medio das esferas aumenta pela eliminacao das esferas menores com o consequente crescimento das maiores pelo processo conhecido por Ostwald ripening
The cause of Ostwald ripening
is due to that the solubility of monomers in water increases with a decreasing monomer droplet size, and larger monomer droplets therefore grow in size at the expense of smaller ones through monomer diffusion (10-12).
Keywords: Miniemulsion, Ostwald ripening
, enhanced nucelation, hybrid latexes, encapsulation, droplet and particle size distributions, reaction kinetics, reaction mechanisms
1 does not consider the effect of Ostwald ripening
in the population balance of the drops, although its influence on the aggregation rate can be appraised (Cruz-Barrios et al.
D, the most effective substances against emulsion breakdown (creaming, flocculation, Ostwald ripening
, coalescence and phase inversion) are block and graft polymers, such as hydrophobically modified inulin in oil-in-water (o/w) emulsions and chains of polyhydroxy-stearic acid and polyethyleneoxide in water-in-oil emulsions (w/o).
(10, 11) based on dissolution of the minor phase molecules from the surface of smaller domains having higher surface energy, diffusion of the molecules through the liquid matrix, and condensation on the more thermodynamically stable larger domains was recently proposed (7-9, 12, 13) as the dominant coarsening mechanism in quiescent melts (as encountered in compression molding) of polymer blends of high molecular weight and high viscosity matrices.
This promotes the diffusive transfer of oil through the water phase, a phenomenon known as Ostwald ripening