Among known molecular magnets, Prussian blue (catena-[MFe III {Fe II (CN) 6 }] (M Li, Na, K, NH 4 )) and related cyanometallate-based coordination polymers offer a range of compounds with unique versatility. The variety of structures and magnetic properties of this family of compounds has been extensively investigated, [1] and recently reviewed. [2] Although much work has focused on the relationship between the unitcell structure and magnetic properties, relatively few attempts have been made towards understanding and controlling the growth mechanism of these magnetic coordination polymers. This is an important aspect in the study of molecular magnets because compounds with appropriate magnetic properties require further fabrication and processing if functional devices and materials are to be produced.Recently, organic supramolecular templates and organized reaction media have been used for the construction of higherorder assembly of traditional inorganic solids, such as silica, [3] calcium carbonate, [4] and iron oxides. [5] These processes allow the control of properties such as particle size, particle shape, surface texture, and organization to be integrated directly into the synthesis method. It seems feasible that similar strategies could also be developed for the coupled synthesis and construction of both molecular materials and coordination polymers to produce complex functional materials that are organized beyond the length scale of the unit cell. As a first step towards this objective, we address the possibility of coupling the synthesis of Prussian blue crystals with its emergent properties such as size, shape, and higher-order assembly.Periodically banded arrangements (Liesgang bands) have been produced previously for the precipitation of Prussian blue on perfluorinated membranes. [6] Similarly, a dissipative structure has been briefly reported. [7] More recently, the growth of Prussian blue under Langmuir monolayers [8] and in the interlayer spaces of lamellar vesicles has been described. [9] These studies have focused on the spatial confinement of Prussian blue rather than the colloidal and mesoscale properties of the constituent crystals. Herein, we show that by confining the synthesis to nanoscale water droplets formed in reverse microemulsions prepared from the anionic surfactant sodium bis(2-ethylhexyl)sulfosuccinate (AOT), hydrophobic Prussian blue nanoparticles with a uniform shape and size can be routinely prepared. A related material, [Cu 2 {Fe(CN) 6 }], has been recently synthesized in microemulsion media, although the resulting nanoparticles were highly disorganized. [10] In our experiments, the growth of the nanoparticles within the restricted reaction field is controlled by a multistep process involving the slow photoreduction of [Fe(C 2 O 4 ) 3 ] 3À to produce Fe II ions that subsequently react with [Fe(CN) 6 ] 3À ions to generate nuclei and clusters of Prussian blue encapsulated within the water droplets. Growth of the molecular magnet occurs by further exchange and fusion between...

Although considerable effort has been dedicated to the controlled synthesis of nanoparticles with classical inorganic structures, there are few reports on the formation of nanoscale materials based on supramolecular compounds such as transition metal coordination polymers. Here we describe the synthesis of crystalline nanoparticles of three different molecule-based magnetic materials, cobalt hexacyanoferrate, cobalt pentacyanonitrosylferrate, and chromium hexacyanochromate, by coprecipitation reactions involving mixtures of water-in-oil microemulsions. The cobalt-containing nanoparticles are regular in shape and size and have dimensions between 12 and 22 nm depending on the concentration of the reactants trapped within the water droplets. At sufficiently high particle concentrations, superlattice structures are formed by solvent evaporation. Growth of the nanoparticles occurs by interdroplet aggregation of primary clusters that are nucleated in the confined spaces of the microemulsion reaction field.

This study showed pronounced changes in the Raman scattering of silicon powder during high-energy ball milling. The powders were milled for 1–18 h in a steel ball mill in argon. The approximate pressure imposed on particles was 2 GPa. The spectra of the as-milled powders were compared with the initial silicon. It was found from the Raman peak position shifts that milling generated strains in the silicon lattice, bringing about a transformation of cubic silicon to tetragonal silicon and amorphization. The relative amount of new phases was determined from the area under the measured Raman peaks.

Please cite this article as: Schöbel, M., Altendorfer, W., Degischer, H.P., Vaucher, S., Buslaps, T., Di Michiel, M., Hofmann, M., Internal stresses and voids in SiC particle reinforced aluminum composites for heat sink applications, Composites Science and Technology (2011), doi: 10.1016/j.compscitech.2011 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. of 19Internal stresses and voids in SiC particle reinforced aluminum composites for heat sink applications of 19 AbstractMetal matrix composites (MMC) are being developed for power electronic IGBT modules, where the heat generated by the high power densities has to be dissipated from the chips into a heat sink. As a means of increasing long term stability a base plate material is needed with a good thermal conductivity (TC) combined with a low coefficient of thermal expansion (CTE) matching the ceramic insulator. SiC particle reinforced aluminum (AlSiC) offers the high TC of a metal with the low CTE of a ceramic. Internal stresses are generated at the matrix-particle interfaces due to the CTE mismatch between the constituents of the MMC during changing temperatures. Neutron and synchrotron diffraction was performed to evaluate the micro stresses during thermal cycling. The changes in void volume fraction, caused by plastic matrix deformation, are visualized by synchrotron tomography. The silicon content in the matrix connecting the particles to a network of hybrid reinforcement contributes essentially to the long term stability by an interpenetrating composite architecture.

Crystal tectonics involves the chemical-based construction and self-assembly of organized materials from solid-state building blocks, such as inorganic nanoparticles. This Perspective describes, through a series of examples, how the architectural complexity of materials with higher-order structure can be controlled by organic templating, interparticle molecular recognition and mesophase transformation. It is shown how the coupling of synthesis and self-assembly over multiple length scales is leading to new horizons in the chemistry of organized matter.