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Egon Matijević

Bio: Egon Matijević is an academic researcher from Center for Advanced Materials. The author has contributed to research in topics: Particle & Particle size. The author has an hindex of 81, co-authored 466 publications receiving 25015 citations. Previous affiliations of Egon Matijević include Yokohama National University & Yokohama City University.


Papers
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Journal ArticleDOI
01 Mar 1978
TL;DR: In this article, the methods of preparation of ferric hydrous oxide sots consisting of particles, uniform in shape, of narrow size distribution are described in detail, and complete domains are given in terms of the ferric salt and corresponding acid concentrations which delineate regions of particle formation of given chemical composition and shape.
Abstract: The methods of preparation of ferric hydrous oxide sots consisting of particles, uniform in shape, of narrow size distribution are described in detail. To produce such sots, acidic solutions, containing ferric ions and nitrate, perchlorate, or chloride ions, respectively, were aged at elevated temperatures for times ranging from a few hours to a few weeks. Solids formed from the solutions containing chloride consisted of either β-FeOOH or α-Fe2O3 depending on the concentration of ferric and chloride ions, whereas particles generated in solutions containing nitrate or perchlorate ions consisted of α-Fe2O3. Particle shape varied greatly as the conditions of colloid preparation were altered. It was possible to produce systems consisting of cubic, ellipsoidal, pyramidal, rodlike, and spherical particles. Such dispersions differed greatly in color. Complete domains are given in terms of ferric salt and corresponding acid concentrations which delineate regions of particle formation of given chemical composition and shape. Electrokinetic measurements show relatively small difference in point of zero charge for the various sots studied.

724 citations

Journal ArticleDOI
TL;DR: In this article, the achievements and problems in the preparation of uniform colloids by precipitation from homogeneous electrolyte solutions are reviewed, and the physical and chemical mechanisms of their formation are discussed.
Abstract: The achievements and problems in the preparation of uniform colloids by precipitation from homogeneous electrolyte solutions are reviewed. Specifically, the syntheses of [open quotes]monodispersed[close quotes] particles of simple and mixed compositions as well as of coated and hollow particles of different shapes are described, and the physical and chemical mechanisms of their formation are discussed. 126 refs., 25 figs., 1 tab.

639 citations

Journal ArticleDOI
01 Mar 1980
TL;DR: In this article, the formation of iron oxides by aging ferrous hydroxide gels at elevated temperatures was studied as a function of various parameters, including the nature of the anions present in the system.
Abstract: The formation of iron (hydrous) oxides by aging ferrous hydroxide gels at elevated temperatures was studied as a function of various parameters. It was found that the composition and the morphology of the resulting solids depended strongly on the nature of the anions present in the system. Spherical magnetite particles of narrow size distribution, with mean diameters ranging between 0.03 and 1.1 μm, were obtained if FeSO4 was interacted with KOH in the presence of nitrate ion and the resulting gelatinous suspension was kept at 90°C for several hours. The particle size distribution of the magnetite sol was affected by the excess concentration of Fe(II) species in equilibrium with the ferrous hydroxide precipitate. If oxygen was present in addition to nitrate ion, rodlike α-FeOOH particles crystallized along with the magnetite on aging of some ferrous hydroxide gels. A mechanism of the magnetite formation under the conditions of these experiments is offered.

610 citations

Journal ArticleDOI
TL;DR: In this paper, a review article deals with the preparation, characterization and mechanisms of formation of uniform simple and composite metal particles of different modal diameters and shapes by reduction of metal ions, in uncomplexed or complexed state with suitable reducing agents and appropriate additives.
Abstract: This review article deals with the preparation, characterization and mechanisms of formation of uniform simple and composite metal particles of different modal diameters and shapes In principle, such dispersions can be obtained by reduction of metal ions, in uncomplexed or complexed state, with suitable reducing agents and appropriate additives The effect of the redox potential in a given oxidation/reduction system on the nature of the final particles is discussed in some detail In another approach monodispersed particles of metal compounds are prepared first and then reduced to pure metals either in a liquid or a gaseous medium In doing so, one can produce powders of a given morphology by selecting the precursor particles of the desired shape A special case is represented by coated particles, consisting of cores and shells of different chemical composition Depending on the materials, it is possible to reduce either one or both components by appropriate chemical reactions

518 citations

Journal ArticleDOI
01 Apr 2003
TL;DR: Stable concentrated aqueous dispersions of silver nanoparticles of narrow size distribution were prepared by reducing silver nitrate solutions with ascorbic acid in the presence of Daxad 19 (sodium salt of a high-molecular-weight naphthalene sulfonate formaldehyde condensate) as stabilizing agent.
Abstract: Stable concentrated aqueous dispersions of silver nanoparticles of narrow size distribution were prepared by reducing silver nitrate solutions with ascorbic acid in the presence of Daxad 19 (sodium salt of a high-molecular-weight naphthalene sulfonate formaldehyde condensate) as stabilizing agent. The latter has excellent ability to prevent the aggregation of nanosize silver at high ionic strength and high concentration of metal (up to 0.3 mol dm(-3)). The presence of the dispersing agent on the surface of silver particles was confirmed by ATR-FTIR spectroscopy and electrokinetic measurements, explaining both the negative charge over the entire pH range and the electrosteric effect responsible for their long-term stability. The other experimental conditions, i.e., the pH of the reacting solutions, the concentration of the stabilizing agent, and the metal/dispersant ratio, also have a significant impact on the size and stability of these dispersions. The final nanosize silver can be obtained as dried powder, and can be fully redispersed in deionized water by sonication.

426 citations


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Journal ArticleDOI
TL;DR: A review of gold nanoparticles can be found in this article, where the most stable metal nanoparticles, called gold colloids (AuNPs), have been used for catalysis and biology applications.
Abstract: Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

11,752 citations

Journal ArticleDOI
TL;DR: Monolayers of alkanethiolates on gold are probably the most studied SAMs to date and offer the needed design flexibility, both at the individual molecular and at the material levels, and offer a vehicle for investigation of specific interactions at interfaces, and of the effect of increasing molecular complexity on the structure and stability of two-dimensional assemblies.
Abstract: The field of self-assembled monolayers (SAMs) has witnessed tremendous growth in synthetic sophistication and depth of characterization over the past 15 years.1 However, it is interesting to comment on the modest beginning and on important milestones. The field really began much earlier than is now recognized. In 1946 Zisman published the preparation of a monomolecular layer by adsorption (self-assembly) of a surfactant onto a clean metal surface.2 At that time, the potential of self-assembly was not recognized, and this publication initiated only a limited level of interest. Early work initiated in Kuhn’s laboratory at Gottingen, applying many years of experience in using chlorosilane derivative to hydrophobize glass, was followed by the more recent discovery, when Nuzzo and Allara showed that SAMs of alkanethiolates on gold can be prepared by adsorption of di-n-alkyl disulfides from dilute solutions.3 Getting away from the moisture-sensitive alkyl trichlorosilanes, as well as working with crystalline gold surfaces, were two important reasons for the success of these SAMs. Many self-assembly systems have since been investigated, but monolayers of alkanethiolates on gold are probably the most studied SAMs to date. The formation of monolayers by self-assembly of surfactant molecules at surfaces is one example of the general phenomena of self-assembly. In nature, self-assembly results in supermolecular hierarchical organizations of interlocking components that provides very complex systems.4 SAMs offer unique opportunities to increase fundamental understanding of self-organization, structure-property relationships, and interfacial phenomena. The ability to tailor both head and tail groups of the constituent molecules makes SAMs excellent systems for a more fundamental understanding of phenomena affected by competing intermolecular, molecular-substrates and molecule-solvent interactions like ordering and growth, wetting, adhesion, lubrication, and corrosion. That SAMs are well-defined and accessible makes them good model systems for studies of physical chemistry and statistical physics in two dimensions, and the crossover to three dimensions. SAMs provide the needed design flexibility, both at the individual molecular and at the material levels, and offer a vehicle for investigation of specific interactions at interfaces, and of the effect of increasing molecular complexity on the structure and stability of two-dimensional assemblies. These studies may eventually produce the design capabilities needed for assemblies of three-dimensional structures.5 However, this will require studies of more complex systems and the combination of what has been learned from SAMs with macromolecular science. The exponential growth in SAM research is a demonstration of the changes chemistry as a disciAbraham Ulman was born in Haifa, Israel, in 1946. He studied chemistry in the Bar-Ilan University in Ramat-Gan, Israel, and received his B.Sc. in 1969. He received his M.Sc. in phosphorus chemistry from Bar-Ilan University in 1971. After a brief period in industry, he moved to the Weizmann Institute in Rehovot, Israel, and received his Ph.D. in 1978 for work on heterosubstituted porphyrins. He then spent two years at Northwestern University in Evanston, IL, where his main interest was onedimensional organic conductors. In 1985 he joined the Corporate Research Laboratories of Eastman Kodak Company, in Rochester, NY, where his research interests were molecular design of materials for nonlinear optics and self-assembled monolayers. In 1994 he moved to Polytechnic University where he is the Alstadt-Lord-Mark Professor of Chemistry. His interests encompass self-assembled monolayers, surface engineering, polymers at interface, and surfaces phenomena. 1533 Chem. Rev. 1996, 96, 1533−1554

7,465 citations

Journal ArticleDOI
13 Dec 2002-Science
TL;DR: Monodisperse samples of silver nanocubes were synthesized in large quantities by reducing silver nitrate with ethylene glycol in the presence of poly(vinyl pyrrolidone) (PVP), characterized by a slightly truncated shape bounded by {100, {110}, and {111} facets.
Abstract: Monodisperse samples of silver nanocubes were synthesized in large quantities by reducing silver nitrate with ethylene glycol in the presence of poly(vinyl pyrrolidone) (PVP). These cubes were single crystals and were characterized by a slightly truncated shape bounded by {100}, {110}, and {111} facets. The presence of PVP and its molar ratio (in terms of repeating unit) relative to silver nitrate both played important roles in determining the geometric shape and size of the product. The silver cubes could serve as sacrificial templates to generate single-crystalline nanoboxes of gold: hollow polyhedra bounded by six {100} and eight {111} facets. Controlling the size, shape, and structure of metal nanoparticles is technologically important because of the strong correlation between these parameters and optical, electrical, and catalytic properties.

5,992 citations

Journal ArticleDOI
TL;DR: This review focuses on the synthesis, protection, functionalization, and application of magnetic nanoparticles, as well as the magnetic properties of nanostructured systems.
Abstract: This review focuses on the synthesis, protection, functionalization, and application of magnetic nanoparticles, as well as the magnetic properties of nanostructured systems. Substantial progress in the size and shape control of magnetic nanoparticles has been made by developing methods such as co-precipitation, thermal decomposition and/or reduction, micelle synthesis, and hydrothermal synthesis. A major challenge still is protection against corrosion, and therefore suitable protection strategies will be emphasized, for example, surfactant/polymer coating, silica coating and carbon coating of magnetic nanoparticles or embedding them in a matrix/support. Properly protected magnetic nanoparticles can be used as building blocks for the fabrication of various functional systems, and their application in catalysis and biotechnology will be briefly reviewed. Finally, some future trends and perspectives in these research areas will be outlined.

5,956 citations