Oleic acid-coated particles

The preparation of the y - FefO nanoparticles and mixtures was as follows. Oleic-acid-coated hydrophobic particles were s mthesized by the coprecipitation of Fe(II) and Fe(III) cations using ammonia. The s mthesized NPs were, on average, 11 nm in size. In order to promote NP growth,... 

KPS as initiator [163]. Liu et al. [164] started with bilayer oleic-acid-coated iron oxide nanoparticles and applied the combination of soap-free and seeded emulsion polymerization (Fig. 20a) to produce GMA-functionalized magnetic poly(MMA-DVB-GMA) microspheres. This was followed by modification of the PGMA shell with EDA to introduce amino groups that can react with the organic dye fiuorescein isothiocyanate and that impart multifunctional, photoluminescence, superparamag-netic and pH-responsive properties to the particles (Fig. 20b). 

Ramfrez et al. encapsulated double-layer (oleic acid and SDS) surfactant-coated magnetite into polystyrene particles by miniemulsion polymerization [171]. In the three-step process, oleic-acid-coated magnetite and oleic acid/SDS double-coated magnetite were prepared in the first and second step, respectively. The third step consists of the preparation of a miniemulsion by stirring 1 h for pre-emulsification, followed by ultrasonication for 2 min using St as monomer with hexadecane and SDS in water. The encapsulation of magnetite was accomplished by cosonication of an St miniemulsion and SDS-stabilized magnetite nanoparticles. The polymerization was initiated by KPS at 80°C. 

F re 2.14 Oleic acid-coated magnetite particles in octane. 

BAM showed bright regions due to the Ag particles and dark regions occupied primarily by oleic acid (Fig. 10b). TEM showed monolayer domains of surfactant-coated silver particles within regions of oleic acid. Vertical transfer onto quartz plates of up to eight layers with good linearity was reported. 

The saponified fatty acids which are used are most often palmitic, stearic or oleic acid but the way in which they confer a hydrophobic nature to the surface of the ink particle is not well understood. If enough calcium ions are present (and these sometimes need to be added to the system) insoluble calcium salts of the fatty acids are probably produced and these may coat the surface of the print particle making it hydrophobic. The ink particle then adheres to an air bubble and can be floated out of the stock. The saponified fatty acids are often called collectors —a term which comes from mineral flotation. 

We now focus on a ferrofluid of single-domain particles of the amorphous alloy Fei cC c (x 0.2-0.3). The particles were coated with a surfactant (oleic acid) and dispersed in a carrier hquid (xylene). The particle shape is nearly spherical (see Fig 3.14) and the average particle diameter d = 5.3 0.3nm. The... 

Solution phase chemical synthesis is a convenient way for making surfactant coated magnetic nanoparticles, as described in various reviews [12-18]. Monodisperse Co nanoparticles with standard deviation less than 10% are synthesized by decomposition of Co2(CO)8 [19-22] or Co(rj3-C8Hi3X n4-C8Hi2) [23] and reduction of cobalt salt [24,25] in the presence of oleic acid and trialkylphosphine, or trialkylphosphine oxide, or alkylamine. Monodisperse iron nanoparticles are normally prepared from decomposition of Fe(CO)5 [26-28]. However, metallic iron-based particles from this decomposition procedure are difficult to characterize due to the chemical instability. A recent synthesis using decomposition of Fe[NSiMe3)2]2 offers a promising approach to monodisperse Fe nanocrystals [29]. 

The encapsulation of magnetite particles into polystyrene particles was efficiently achieved by a miniemulsion process using oleoyl sarcosine acid [ 109] or the more efficient oleic acid as first surfactant system to handle the interface magnetite/styrene, and SDS to stabilize the interface styrene/water, thus creating a polymer-coated ferrofluid (Fig. 15b). Since the magnetite particles were very small (ca. 10 nm), each polymer particle was able to incorporate many inorganic nanoparticles. A content of 20 wt% could be incorporated in this way. 

Surelease. a product of Colorcon. is produced by first melt extruding ethylcellulose with oleic acid and dibutyl sebacate (DBS) (or fractionated coconut oil) to form a molten plasticized polymeric blend. This molten blend of plasticized ethylcellulose is then introduced into an ammoniated water solution under high shear and pressure to disperse small droplets of plasticized ethylcellulose into the water phase (67). Ammonium oleate is produced in situ during this emulsification process to stabilize the colloidal ethylcellulose particles (67). Additional purified water is then added to reduce the final solids content of the pseudolatex dispersion to 25%. The Surelease coating system does not contain an ionic surfactant, and therefore does not exhibit the pH-dependent drug relea.se observed with Aquacoat ECD (66),... 

Lubricants are fatty acids or salts of fatty acids such as stearic or oleic acids in ethanol solvent. The lubricant coats the silver particles during the miUmg process and is retained during subsequent processing because it becomes chemisorbed on the particle surfaces. Untreated particles appear as aggregates of submicron particles, typically 100 pm in size, presumably due to the high surface tension of the... 

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