ISSN:
1435-1536
Keywords:
Microemulsion
;
hard sphere
;
metastability
;
nucleation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract In this paper we bring together some recent results concerning the stability and properties of O/W microemulsion droplets in a ternary system composed of water, decane and the nonionic surfactant pentaethylene glycol dodecylether (C12E5). Stable microemulsion droplets can be prepared when the spontaneous curvature has a finite but not too low value. Near the limit of maximum oil solubilisation the droplets adopt a spherical shape with low polydispersity. Experimental results obtained from low shear viscosity, collective and long time self-diffusion and static light scattering show that the spherical droplets interact to a very good approximation as hard spheres over a large range of volume fractions. A supersaturated microemulsion can be prepared by a rapid temperature quench (drop) into the two-phase area where a smaller droplet size coexists with excess oil. In the two-phase area, we can distinguish a region near the microemulsion phase boundary where the droplets are metastable, from a region further away from the boundary where the droplets are unstable and the oil-phase nucleates instantaneously. Treating the initial phase separation as a homogeneous nucleation it is possible to calculate an activation energy within the curvature energy approach.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01189484
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