Nanopartides morphology

Venier-Julienne, M.C. and Benoit, J.P. (1996) Preparation, purification and morphology of polymeric nanopartides as drug carriers. Pharmaceutica Acta Helvetiae, 71, 121—128. 

Hydrothermal synthesis is a powerful method used for the fabrication of nanophase materials due to the relatively low temperature during synthesis, facile separation of nanopartides in the product, and ready availability of apparatus for such syntheses. Versatile physical and chemical properties of nanomaterials can be obtained with the use of this method that involves various techniques (e.g., control of reaction time, temperature and choice of oxidant and its concentration). Several extensive reviews are available that discuss the fundamental properties and applications of this method [2, 3]. These reviews cover the synthesis of nanomaterials with different pore textures, different types of composition [2, 4—6], and different dimensionalities in terms of morphology [6-8]. 

Gold nanostructures of various sizes and morphologies were synthesized at room temperature using naturally occurring biodegradable plant surfactants [ 76]. The sizes and shapes (spherical, prisms, and hexagonal) of the synthesized nanopartides were dependent on the concentration of the gold ions and the type of plant surfactant used for preparation. 

Presently, the scientific community is making every effort to study irmovative catalytic materials that combine morphological features suited to a fast counterdiffusion of PO, surface properties designed to favor the desorption of PO and limited side-reactions deriving from acid or base-catalyzed reactions - especially those leading to heavy product accumulation - as well as to stabilizing metal nanopartides. 

Fig. 1.6 Summary of representative morphologies of bimetallic nanopartides (Reprinted with permission from ref 16a, Kunitake and Toshima groups,/ Am. Chem. Soc. 2003, 725, 11034).

The planar order of nanostructures deposited by chemical routes has become an important issue, because of the competition with solid-state nanotechnology cap>able of the fabrication of fine two-dimensional structures. The main concern is with the layers of nanopartides produced by chemical self-assembly, because methods of electrostatic self-assembly and LB is not capable of producing two-dimensional ordered arrays of nanopartides. The features of the lateral arrangement of particles, which are buried under layers of either closely packed amphiphilic compounds or polymers, are usually smeared and difficult to observe. In the case of relatively thick (quasi-3D) films, produced by electrodeposition and sol-gel techniques, the morphology study usually reveals polycrystallites. Therefore, the quality of these materials can be assessed by the size of the crystallites and by the presence of preferential orientation, which may cause anisotropy of the electrical and optical prop>erties of materials. 

Morphology and crystallography of chemically self-assembled nanopartides... 

Thomas Russell is Silvio O. Conte Distinguished Professor, Polymer Science and Engineering Department Director, Energy Frontier Research Center (EFRC), Polymer-Based Materials for Harvesting Solar Energy. His research interests are polymer-based nanoscopic structures, polymer-based nanopartide assemblies, electrohydrodynamic instabilities in thin polymer films, surface and interladal properties of polymers, polymer morphology kinetics of phase transitions, and supercritical fluid/polymer interactions. 

Incorporation of nanopartides affects blend rheology through the morphology modification and/or viscoelasticity of the phases. Most tests have been carried out in dynamic shearing. Owing to the lack of theoretical analysis of tertiary systems only the experimental data have been presented. 

Elias, L., Fenouillot, F., Majeste, J.C., and Cassagnau, Ph. (2007) Morphology and rheology of immisdble polymer blends filled with silica nanopartides. Polymer, 48, 6029. 

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