NP Surfactant templating

Figure 2.8 Illustration of two-step preparation of NP/surfactant-templated tungstated...

Figure 2.9 TEM image of NP/surfactant-templated W0 c/Zr02 (calcined at 600 = C)...

The two forms of NP-supported W0 c/Zr02 materials (prepared from NP/surfactant templating and sol-gel chemistry) are active for the dehydration of methanol to dimethylether [89], according to methanol oxidation studies [90,91]. It is hypothesized that these NP-supported materials contain a larger amount of polytungstates than conventionally prepared W0 c/Zr02 and therefore are more active [89],... 

Two kinds of solution were prepared in advance. Solution A was a water solution containing an Si source, which was obtained by hydrolyzing metal alkoxide (tetraethylorthosilicate, TEOS) with a dilute tetrapropylammoniumhydroxide (TPA-OH)/water solution at room temperature. The molar ratio of Si to the template was 3. In peparation of ZSM-S zeolite nanoerystals, aluminium isopropoxide as an A1 source and sodium chloride were added into solution A. Solution B was an oi mic solution containing surfectant Nonionie surfactants, poljraxyethylene (15) cxslylether (C-15), polyoxyethylene (15) nonylphenylether (NP-15), and polyoxyethylene (15) oleylether (O-15), and ionic surfoctnnts, sodium bis(2-ethylhexyl) sulfosucdnate (AOT) and... 

This chapter describes the non-LBL approaches of tandem assembly and interfacial stabilization for the formation of closed shell structures, with an emphasis on ensembles in which NPs constitute the shell. Tandem assembly is a versatile and environmentally friendly route to the formation of useful NP-shelled capsules. In contrast to sacrificial core templating and LBL assembly methods, tandem assembly has the important differentiating feature that it avoids the incineration or solvent dissolution step to generate the hollow interior of the capsule. Enhancements in optical, mechanical, catalytic, and release properties of such materials hold great promise for their application in photoresponsive delivery systems, catalysis, and encapsulation. Interfacial stabilization routes are found to yield NP-shelled structures in the form of emulsions and foams that have enhanced stability over those from conventional, surfactant-based approaches. Unusual interactions of the NP with fluid interfaces have made possible new structures, such as water-in-air foams, colloidosomes, and anisotropic particles. 

Microemulsion formation represents one of the most popular template syntheses suitable surfactant molecules are dissolved in a hydrophobic solvent to form small vesicles cmitaining an aqueous medium (Fig. 6.5) [63, 102-107]. Such a methodology is adopted in the synthesis of metal NPs the chemical reduction of metal ion precursors to zero-valence metal occurs in the aqueous phase. After a... 

To act as possible "conductive bridges between adjacent CNTs, it would also be favorable when the metal NPs are in the vicinity of the CNTs. For this reason, a system in which the AuNPs are grown on the CNTs would be beneficial. This methodology also allows one to control the concentration of AuNPs in the final CNT dispersions. The inability to do this was shown to be the main disadvantage of the synthetic methodologies utilized in the previous section that dealt with QD-containing composites. An amphiphilic block copolymer or water-soluble homopolymer can be used both as a surfactant for the dispersion of individual CNTs, and as a template onto which AuNPs can be grown. 

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