Surface nanoreactor

Finally, reactions in the surface nanoreactors were found to be important for biological objects such as DNA and pheromones some hypotheses were advanced that the analogues of the surface nanoreactors might have played a significant role in biological evolution. 

Possibilities offered from structuring the surface as array of nanoreactors... 

Fig. 3 shows a conceptual example of the possibilities offered from structuring the surface of oxides in terms of array of Ti02 nanotubes which can be viewed as an ensemble of nanoreactors. The SEM image in the inset of Fig. 3 shows an example of the Ti02 nanostructures obtained in the case of anodic oxidation of titanium foils. ... 

Fig. 3 Concept of nanoengineering of oxide catalytic surface in terms of nanoreactor array, some of the possibilities offered by this concept (in particular in terms of realizing multifunctional catalysts for cascade reactions in nanoconfined liquids) and a SEM image of an array of Xi02 nanotubes produced by anodic oxidation of Ti foils. Source Centi et alN...

Dendrimers are a special class of arborescent monodisperse nanometer sized molecules that have been used in the synthesis of Au NPs as surface stabilizers or nanoreactor/templates for nanoparticle growth. Moreover, these hybrid nanomaterials have great potential for application in different fields such as sensors, imaging in cells, electrooptical devices, catalysis, drug delivery agents, and so on. 

G. Tovar describes one of the novel chemical applications of modern colloidal systems by using such miniemulsions (in addition to classical suspension polymerization) for molecular imprinting. Here, the stable nanoreactor situation is used to synthesize particle surfaces with molecular sized cavities for biomedically relevant species or species to be separated from each other. Such receptor sites are nowadays preferentially made by the pathways of modern colloid chemistry. 

A further possible extension regards the possibility to optimize the design of the hosting metal-oxide support, and to structure the surface in terms of nanoreactors that host the liquid film (Figure 2.15) [140]. By anodic oxidation and other techniques it is possible to prepare various metal oxides showing a nanostructure characterized by an ordered array of ID elements, such as nanotubes. The possibilities offered for catalysis by this design in the case of Ti02 materials have been discussed recently. 

Organized and constrained media may provide cavities and surfaces, sometimes called microreactors or nanoreactors,171 that can control the selectivity of photochemical reactions of reactants. There are many types of microreactors, for example, molecular aggregates of micelles or monolayers, macrocyclic host cavities of crown ethers or cyclodextrins and microporous solid cavities and/or surfaces of zeolites, silica or... 

Recently, dendrimers loaded with Cu ions were used as template for silica formation [68]. As is well known,poly (propylene)imine dendrimer (DAB-Am-64) serves as a nanoreactor for well controlled nanoparticle formation [69]. However, when such dendrimers alone are used as silica templates [68], it does not lead to high porosity (BET surface area is 290 m /g) and does not provide ordering (Fig. 8). The latter factor is important for optical properties, but of no concern for catalytic applications. However, as silica cast over Cu-DAB-Am-64 lacks interpenetrating pore system and easy access to CuO particles, this destroys any hopes for catalytic applications as well. 

Gitsov et al 10) produced a nanoreactor fi om laccase and linear poly(ethylene oxide)-dendritic poly(benzyl ether) diblock copolymers. A notable feature of this system is the presence of hydrophobic dendritic pockets that increase the local concentration of water-insoluble organic compounds near the active site where they are oxidized. Li and Hsieh (77) employed a hydrogel fiber membrane, with a large surface area and improved organic solvent solubility in order to facilitate lipase reactions. He (72) grafted lipase onto silica particles, which permitted him to carry out synthesis of polyesters, polycarbonates, polyphosphates, and their copolymers at temperatures up to 150°C. 

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