Ostwald ripening


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Ostwald ripening

[′ȯst‚vält ¦rīp·ə·niŋ]
(chemistry)
Solution-crystallizer phenomenon in which small crystals, more soluble than large ones, dissolve and reprecipitate onto larger particles.
References in periodicals archive ?
During the isothermal aging process, the diameter of the 1[micro]m Bi-rich particles in the solder bulk increased by about 50%, with aging time by Ostwald ripening. The thickness of the interfacial intermetallic compound in all the solder joints increased slightly during the aging process.
Among his topics are a general classification of polymeric surfactants and their solution properties, the adsorption and conformation of polymeric surfactants at interfaces, interaction between particles or droplets containing adsorbed polymer layers and the theory of steric stabilization, Ostwald ripening in dispersions and its prevention, emulsion coalescence and its prevention, and flow characteristics (rheology) of formulations.
The research team showed that a process called Ostwald ripening -- where the nanoparticles that grow the carbon nanotubes change in size to larger diameters -- is a key contender against producing the infinitely more useful size.
The growth and coarsening of liquid globules mainly depends on Ostwald ripening, Brownian motions, Marangoni migration, and Stokes movement.
Four important steps in chemical synthesis of nanoparticles which aid particle size and uniformity are nucleation, growth of the colloidal particles, Ostwald ripening, and stabilization.
Very polar oils can also lead to Ostwald ripening, which is related to the molecular diffusion of oil molecules through the water phase from smaller oil droplets into the thermodynamically favored larger oil droplets (for O/W emulsions).
Furthermore, based on the experimental results, we considered that the formation mechanism of the as-synthesized product of nitrogen-doped ZnS Camellia Brushfield Yellowlike structure could be explained by a synergic effect of Ostwald ripening and the self-assembled mechanism as proposed in Figure 6.
* O diametro medio das esferas aumenta pela eliminacao das esferas menores com o consequente crescimento das maiores pelo processo conhecido por Ostwald ripening.
One reason is that the stability of miniemulsified monomer droplets was insufficient to resist coalescence and 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