Discrete particle encapsulation

Another commonly used application-specific method is discrete particle encapsulation (DPE). In this method, selected chemicals are used to form a thin polymeric shell around each nanoparticle providing the characteristics a user needs. Then a second thin-shell coating is added, so the nanoparticle will disperse in the best needed format. This shell contains spacer molecules that prevent the nanoparticles from coming into contact with each other. The result is steric stabilisation for nanoparticles in non liquid solvents and polymers, and electrosteric stabilisation for those needing to disperse in a fluid. 

Wurster DE, Lindlof JA. Apparatus for the encapsulation of discrete particles. U.S. Patent 1965 3,196,827. 

At low alkali addition levels, the bitumen was attached to air bubbles as discrete particles. This mode of bitumen attachment is also seen at reduced temperatures and is akin to the type of mechanism encountered in mineral flotation. At more reasonable alkali addition levels however, the bitumen will encapsulate the air bubble. The size of the droplets increases with increasing dosage of alkali. Bitumen droplet size was found to be invariant with depth in the separation vessel, and this invariance implies that bitumen droplets do not coalesce as they rise through the middlings phase. 

Encapsulated type. Discrete particles of the colorant are trapped inside zircon crystals, e.g., the iron coral pink where very fine particles of red Fe203 are incorporated in zircon crystals. 

Encapsulation of PNIPAM inside non-temperature-sensitive (PSS/PAH) capsules templated on PS cores was achieved by the same ship in a bottle synthesis [37], providing temperature-responsive microcapsules. Encapsulated PNIPAM collapsed when the temperature of the system increased above 34 °C, forming discrete particles inside the capsule, without modification of the shell (Fig. 3.6). This prop-... 

Lattice type. The dopant ion replaces a Zr ion in the zircon lattice, e.g., vanadium blue (V replaces Zr ) and praseodymium yellow replaces Zr ). Encapsulated type. Discrete particles of the colorant are trapped inside zircon crystals, e.g., the iron coral pink where very fine particles of red Fe203 are incorporated in zircon crystals. 

P. Chereau, FrP 1318773 (1963) CA 58, 13702 (1963), claims rocket fuel or incendiary composed of a combustible metal, eg, Al, Mg, or Li or a liquid fuel such as kerosine, in fine grains or droplets encapsulated in situ by formation of a polymer skin. Thus, 0.18 of 2,4-tolylene diisocyanate is dissolved in 41.8g of paraffin oil. A portion (24.5g) of this mixt is added drop by drop to a stirred soln contg 2g of ethylene glycol in 250g water. Discrete spherical particles... 

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