Metal-core/polymer-shell hybridized

Metal-Core/Polymer-Shell Hybridized Nanocrystals. 153... 

In our research group, this kind of metal-core/polymer-shell type hybridized NCs have been first prepared by the co-reprecipitation method [45], and it was found that LSP dramatically damped without changing its resonance frequency. We have investigated the damping mechanism in detail, and the revealed reasons have provided a novel material design to avoid the LSP damping [47,49]. 

Co-reprecipitation method [45] is one of the improved reprecipitation method to prepare a metal-core/polymer-shell type hybridized NCs, in which silver (Ag) NPs aqueous dispersion liquid was employed as a poor medium, instead of water in the... 

Figure 5 displays the SEM and TEM images of Ag core/poly(ADA)-shell hybridized NCs [50], Actually, Ag core was clearly covered with almost uniform poly(ADA) shell. The thickness of the shell was about 5 nm, and the morphology of the core/shell nanostructure in the present hybridized NCs was dependent remarkably on microwave irradiation conditions [50], For example, the above-mentioned microwave irradiation condition is the most desirable, and the core/shell nanostructure could not be formed successfully when the irradiation condition was 500 W, 20 s or 200 W, 40 s. After co-reprecipitation, the dispersion liquid is considered to be a mixture of Ag NPs and ADA NCs. The heated ADA NCs were probably partially melted by microwave irradiation, and may easily collide and fuse with Ag NPs at the elevated temperature. As a result, molten ADA monomer could adsorb effectively on the surface of Ag core, and was then recrystallized to form solid-state polymerizable ADA shell during the cooling process after microwave irradiation [50]. The present co-reprecipitation and microwave-irradiation method is available for the fabrication of another type of metal-core/ji-conjugated polymer-shell hybridized NCs [107]. 

Polymer-Core/Metal-Shell Hybridized Nanocrystals. 161... 

This polymer-core/metal-shell type of the hybridized NCs has an inverse nanostructure of Sect. 3. Our research group has recently estabUshed the unique fabrication process, visible-light-driven photocatalytic reduction method [53], to PDA-core/metal-shell hybridized NCs. 

The hybrid materials such as oxide/polymer nanocomposites can be prepared by this method. For example, the nanoscale heterogeneity can be of controlled size in metal/ceramic nanocomposites. The reduction of metal-oxides with hydrogen gives nanocomposite powders such as Fe core in the silicon oxide or Fe203 [147] and NiFc204 shell [148]. Metal particles of several nanometers size with narrow size distribution are statistically distributed in the oxide matrix without any agglomerates, as a result of binding the metal complex to oxide matrix. The narrow particle size distribution cannot be obtained if complexion of ions appears (Table 5.6). 

As mentioned earlier in situ approach has also been used for the synthesis of conducting polymer-metal hybrid nanocomposites. Xu et al. [35] have reported the decoration of PPy nanotubes with gold nanoparticles by an in situ reduction process. They prepared PPy nanotubes by MO-FeCl3 self-degrade template method and then reduced HAuCLi within PPy nanotubes in the presence of different surfactants such as sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB) and Tween-80. Nanowires of silver PAni nanocomposites have been reported via in situ polymerization method [36]. In this method aniline is oxidized by ammonium persulfate (APS) in the presence of dodecylbenzene sulfonic acid (DBSA) and silver nitrate (AgN03). In another approach gold-PAni core-shell... 

---