Nanostrukturierung von Festkörpern mit amphiphilen Polymeren

Amphiphilic block copolymers are versatile structure-directing agents for the synthesis of organic nanostructured materials. Chemically well characterized and easily accessible, they can be utilized for a rich variety of applications. While the prefabrication of an ABC “nanoreactor” or a mesoscopic casting mold occur via spontaneous self-assembly (exo-and endo-templating), during biomimetic mineralization the structure of the resulting inorganic-ABC hybrid material is induced upon combining thc components. The underlying methodologies are illustrated using recently published, representative examples.     

Bildung von Calciumtelluriten durch Festkörperreaktionen

By solid state reactions of TeO₂ with CaO or CaCO₃ at temperatures of 500–730°C the compounds CaTe₂O₅ and CaTeO₃ are formed. SrTe₂O₅ and BaTe₂O₅ are obtained under similar conditions as CaTe₂O₅. There are two crystalline modifications of CaTeO₃, which is oxidized by air at higher temperatures. With an excess of CaO or CaCO₃, TeO₂ reacts to give tellurium and Ca₃TeO₆, the latter crystallizing with a cryolite lattice and a₀ = 5.556 Å, b₀ = 5.786 Å, c₀ = 7.982 Å, β ≈? 90°.