Polymer-coated nanoparticles

Kim BJ et al (2007) Importance of end-group structure in controlling the interfacial activity of polymer-coated nanoparticles. Macromolecules 40(6) 1796-1798... 

Absorption through the oral mucosa can take place in two ways i) inter- or paracellular pathway, which is a passive transport through the lipid matrix between the cells and ii) trans- or intracellular pathway through the cell walls, which can be either passive or active transport. The following dosage forms may be used i) polymer-coated nanoparticles, ii) special tablets, iii) pol)mtier films, and iv) gels (patches) [112-119]. 

Plasma is effective in the fabrication of nanocomposites, such as nanoparticles composed of one material and covered by a nanolayer of another. Relevant examples include, in particular, carbon-coated magnetic metal particles produced in thermal arc plasma (McHenry et al., 1994), as well as polymer-coated nanoparticles with improved adhesion, corrosion resistance, and surface passivation produced in RF plasma in a fluidized bed (Shi et al.,... 

The synthesis of core-shell magnetic nanoparticles from polyacrylic acid (PAA) graft copolymers containing side chains of PEO and PPO (Fig. 5) was demonstrated by Hatton et al. [102]. Using a mixture of the polymers at a temperature of 180°C, amine-terminated PEO and PPO were coupled onto the PAA via amidation. Super-paramagnetic polymer-coated nanoparticles were synthesized by the hydrolysis and condensation of Fe(II) and Fe(III) chloride salts in the presence of PPO- or PEO-modified PAA copolymers. The extraction of organic compounds from aqueous media towards the copolymer shell of hydrophobic PPO segments can be applied in the field of water purification. 

Polymer-coated nanoparticles in the 10-50 nm size range with a bismuth sulfide (61283) core and showing superior enhancement capabilities and a circulation time of greater than 2 h have been described. The polymer coating (polyvinylpyrrolidone) prevented aggregation and protein interference, and concentrated the contrast capabilities of the imaging agent. 

Besides rings, spontaneous formation of nanoparticle strip patterns has been observed on dewetting a dilute film of polymer coated nanoparticles floating on a water surface [577]. Hybridization of branched DNA trimers and Au nanoparticle DNA conjugates have been employed to produce discrete self-assembled nanoparticle dendrimers [578]. Self-assembly of triangular and hexagonal CdS nanocrystals into complex structures such as rods and arrows has been observed [579]. Furthermore, self-assembly of CdSe nanoparticle-copolymer mixtures has been observed wherein the copolymers assemble into cylindrical domains that dictate the distribution of the nanoparticles [580]. 

Zhao JJ, Bae SC, Xie F, Granick S (2001) Diffusion of polymer-coated nanoparticles studied by fluorescence correlation spectroscopy. Macromolecules 34(10) 3123-3126... 

Bull MM, Chung WJ, Anderson SR, Kim S-J, Shim I-B, Paik H-J, Pyun J (2010) Synthesis of ferromagnetic polymer coated nanoparticles on multi-gram scale with tunable particle size. J Mater Chem 20(29) 6023... 

Another method to synthesize hollow nanocapsules involves the use of nanoparticle templates as the core, growing a shell around them, then subsequently removing the core by dissolution [30-32]. Although this approach is reminiscent of the sacrificial core method, the nanoparticles are first trapped and aligned in membrane pores by vacuum filtration rather than coated while in aqueous solution. The nanoparticles are employed as templates for polymer nucleation and growth Polymerization of a conducting polymer around the nanoparticles results in polymer-coated particles and, following dissolution of the core particles, hollow polymer nanocapsules are obtained. 

Figure 3. Various type of SERS active metallic nanostructures (a) metal-island films (b) metal-coated nanospheres (semi-nanoshells) (c) metal-coated random nanostructures and (d) polymer coatings embedded with metal nanoparticles. Inset An SEM image of silver-coated polystyrene spheres.

In a more general way, the loading of metal salts into preformed block copolymer micelles has become the most used route for the incorporation of precursors into block copolymer nanostructures because it allows precursor loading with tolerable loading times, it is quite versatile, and it is applicable to a wide variety of precursor/block copolymer/solvent systems. The accordingly synthesized polymer-coated metallic or semiconducting nanoparticles exhibit increased stability, which results in, e.g., protection against oxidation as illustrated by Antonietti et al. [108]. 

Figure 10.5 Spherical ensembles of citrate-stabilized Au nanoparticles onto polymer-coated Si02 cores. Au/Si02 particle sizes (a) 40/330 nm (b) 60/460 nm (c) 80/550 nm. Scale = 200 nm.34 (Reprinted with permission from B. Sadtler and A. Wei, Chem. Commun. 2002, 1604-1605. Copyright the Royal Society of Chemistry.)...

Lee WA, Pernodet N, Li B, Lin CH, Hatchwell E, Rafailovich MH. Multicomponent polymer coating to block photocatalytic activity of Ti02 nanoparticles. Chem Commun 2007 4815-17. 

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. 

Allcock and coworkers developed derivatives of the phosphazene polymers suitable for biomedical applications [35, 36]. Long-circulating in the blood, 100-120 nm in diameter, PEO-coated nanoparticles of the poly(organophospazenes) containing amino acids have been prepared. The PEO-polyphosphazene copolymer or poloxamine 908 (a tetrafunctional PEO copolymer) has been deposited on their surface [37]. 

Wang, Y., et al. (2004), Polymer coating/encapsulation of nanoparticles using a supercritical anti-solvent process, /. Supercrit. Fluids, 28, 85-99. 

If stabilizers or polymers are added post sonication or during sonication, then metal colloids result. These stabilizers could be alkyl thiols, PVP, oleic acid, and SDS. If the sonication is done in the presence of oxygen then oxides are formed. The size of the self-assembled monolayer-coated nanoparticles is determined by the surfactant concentration in the coating solution. 

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