Aggregated particle morphology

Figure 7.5 Two topologically distinct types of mesoporous gold sponge, each with 50 volume % gold, (a) Swiss-cheese morphology produced by de-alloying, (b) aggregated particle morphology produced by sintering of nanoparticles.

ZnO particle morphologies are very complex and diversiform in comparison with Ti02. Thus, monodispersed ZnO particles with well-defined morphological characteristics, such as spherical, ellipsoidal, needle, prismatic, and rod-like shapes, have been obtained. Aggregates composed of these basic shape particles have also been achieved. The methods used for synthesis of these ZnO powders include alkali precipitation [214-216], thermal decomposition [217], hydrothermal synthesis [218], organo-zinc hydrolysis [219], spray pyrolysis [220], and other routes. 

Specific surface area of C5 polyol-boehmite is also much higher (343 m. g" ) than those of C4 polyol-boehmite (168 m. g ) or even of reference boehmite (144 m. g" ) according to the decrease of particle size previously described. In table 1, these specific surface area values measured from Na adsorption/desorption experiment (Sbet) are compared to geometric specific surface area calculated from particle morphological data (Sga,). Sbet values are slightly lower than Sgeo values probably due to particle aggregation. 

To summarize, the primary influence on dehydration rates is most likely differences in particle size (and aggregation), with morphology representing a secondary influence. However, there may be cases where morphology contributes significantly to the process and must at least be ruled out as a factor. 

A wide variety of reactor processes have been reported in the literature and especially in patents. Most reactor designs are aimed at narrowing particle size distributions, controlling copolymer composition and/or particle morphologies, or reducing wall fouling and particle aggregation. 

The cellular uptake efficiency and kinetics together with the correlation between the particle morphology and aggregation of two kind, spherical and tubeshaped particles, of mesoporous silica nanomaterials (MSNs) were investigated... 

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