![]() 38− 40 For example, addition of a long hydrocarbon (or wax) to oil dropletsĮnhances the stability of o/w nanoemulsions toward Ostwald ripening. Phase that is highly insoluble in the continuous phase. Problem can be suppressed by adding a suitable species to the droplet 19, 35− 37 In principle, this instability 13, 15 However, both o/w and w/o nanoemulsions tend to suffer from Ostwald More active formulations when used for drug delivery, 28− 31 food technology, 32, 33 or cosmetics 34 because of their much higher surface area per unit mass. 13− 27 They are much less prone to gravitational creaming or sedimentation Nanoemulsions comprise very fine droplets with a mean diameter Wettability, which is determined by the three-phase contact angleĪt the interface, θ w. 6, 7 In contrast, the key parameter for Pickering emulsions is the particle Is of the oil-in-water (o/w) or water-in-oil (w/o) type is dictatedīy the hydrophilic–hydrophobic balance of a surfactant. Whereas surfactant exchange between the interface and bulk solution Particles remain irreversibly adsorbed at the oil–water interface, They are sufficiently large and possess appropriate wettability, solid Particulate emulsifiers confer different properties compared to small Were first recognized in the early 1900s. In the long-term stability of such nanoemulsions.īy particles, or so-called Pickering emulsions, The salt concentration up to 0.43 M provided no further improvement Reduced by using 0.11 M NaCl instead of pure water. The rate of droplet ripening can be substantially Of these water-in-oil Pickering nanoemulsions is assessed using analyticalĬentrifugation. The effect of varying the NaClĬoncentration within the droplets on their initial rate of Ostwald SAXS studies conducted on a Pickering nanoemulsion prepared usingĠ.11 M NaCl confirms that the aqueous droplets are coated with a loosely The mean number of nanoparticles adsorbed ontoĮach aqueous droplet and their packing efficiency are calculated. The mean size of theseĪqueous droplets can also be tuned by systematically varying the nanoparticleĬoncentration, applied pressure, and the number of passes through Of around 250 nm is obtained at 0.11 M NaCl. Systemically increasing the salt concentration produces significantlyįiner droplets after microfluidization, until a limiting diameter Measurements indicating a mean diameter of more than 600 nm. Leads to the formation of relatively large aqueous droplets with DLS In the absence ofĪny salt, high-pressure microfluidization of such precursor emulsions Of water followed by high-shear homogenization. Precursor Pickering macroemulsions are then prepared by the addition ![]() In n-dodecane using polymerization-induced self-assembly. Stabilized diblock copolymer nanoparticles are prepared
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |