Core-shelled nanocomposite particles

Chen, T.Y. and Somasundaran, R, Preparation of novel core-shell nanocomposite particles by controlled polymer bridging, J. Am. Ceram. Soc., 81, 140, 1998. 

Wang, D., He, J., Rosenzweig, N. and Rosenzweig, Z. (2004) Superparamagnetic Fe203 beads-CdSe/ZnS quantum dots core-shell nanocomposite particles for cell separation. Nano Lett., 4, 409—413. 

Core-shelled nanocomposite particles with polystyrene sphere core and ... 

Core-shell nanocomposite of Mg(OH)2/PMMA with an average particle size of ca. 500nm where Mg(OH)2 is the core and PMMA is the shell was successfidly prepared by the emulsion polymerization of MMA in the presence of surface modified Mj OH)2. The grapelike ( re-shell microspheres with PMMA nodules could he obtained as stable latex. 

Metal nanoparticles embedded in thermosensitive core-shell microgel particles can also work efficiently as catalyst for this reaction. Figure 13 shows the oxidation reaction of benzyl alcohol to benzaldehyde in aqueous media by using microgel-metal nanocomposite particles as catalyst. All reactions were carried out at room temperature using aerobic conditions. It is worth noting that the reaction conditions are very mild and no phase transfer catalyst is needed. It has been found that microgel-metal nanocomposites efficiently catalyze the aerobic oxidation of benzyl alcohol at room temperature. No byproducts have been detected by GC after the reaction, and water is the only product formed besides the aldehyde. 

Cho Choi, J.-W., Yee, A. F., Laine, R. M. Toughening of cubic silsesquioxane epoxy nanocomposites using core-shell rubber particles A three-component hybrid system. Macromolecules 37 (2004) 3267-3276. 

In the case of oxide solid solutions [28-31] or complex oxide formation [26,32-39], a high chemical homogeneity of the precursor promotes fast and uniform formation of the target product during its thermal processing. However, even in the case of non-reacting components, it was shown that cryogel synthesis is useful for the synthesis of nanocomposites [27, 40-54]. It is also possible to synthesize core-shell oxide particles by this method when precipitatimi of the components is performed not simultaneously, but sequentially [55]. 

There is technological interest concerning the use of composite particles in functional coatings, and a number of excellent reviews have been prepared on conductive nanocomposites [53-56]. Although the synthesis of composites always demands some entrapment (encapsulation) of polymers, the following sections will illustrate mainly the core-shell composite particles. These composite particles can be divided broadly into either organic-ICP or inorganic-ICP. 

Giani E, Spamacci K, Laus M, Palamone G, Kapeliouchko V, Arcella V (2003) PTFE-poly-styrene core-shell nanospheres and nanocomposites. Macromolecules 36(12) 4360-4367 17. Antonioli D, Deregibus S, Panzarasa G, Spamacci K, Laus M, Berti L, Frezza L, Gambini M, Boarino L, Enrico E, Comoretto D (2012) PTFE-PMMA core-shell colloidal particles as building blocks for self-assembled opals synthesis, properties and optical response. Polym Int61(8) 1294... 

Figure 5.15 Discharge and charge profiles of (a] the anatase nano-Ti02 particles and (b) rutile Ti02-carbon core-shell nanocomposite at a constant current density of 0.1 mA/cm in the voltage range 1.4-2.5 V. Reprinted from Ref. 71, Copyright 2006, with permission from Elsevier.

Z. Ai, G. Sun, Q. Zhou, C. Xie, Polyacrylate-core/Ti02-shell nanocomposite particles prepared by in situ emulsion polymerization. J. App. Polym. Sci. 102,1466-1470 (2006)... 

Fig. 7.8 TEM images of the Si SiOx/C nanocomposite nanoparticles produced by hydrothermal carbonization of glucose and Si and further carbonization at 750 °C under N2. (a) Overview of the Si SiOx/C nanocomposites and a TEM image at higher magnification (in the inset) showing uniform spherical particles (b) HRTEM image clearly showing the core/shell structure (c), (d) HRTEM image displaying details of the silicon nanoparticles coated with SiOxand carbon.

As for the linear properties, numerous approaches have been proposed to predict and explain the nonlinear optical response of nanocomposite materials beyond the hypothesis leading to the simple model presented above ( 3.2.2). Especially, Eq. (27) does not hold as soon as metal concentration is large and, a fortiori, reaches the percolation threshold. Several EMT or topological methods have then been developed to account for such regimes and for different types of material morphology, using different calculation methods [38, 81, 83, 88, 96-116]. Let us mention works devoted to ellipsoidal [99, 100, 109] or cylindrical [97] inclusions, effect of a shape distribution [110, 115], core-shell particles [114, 116], layered composites [103], nonlinear inclusions in a nonlinear host medium [88], linear inclusions in a nonlinear host medium [108], percolated media and fractals [101, 104-106, 108]. Attempts to simulate in a nonlinear EMT the influence of temperature have also been reported [107, 113]. 

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