Reversible and Irreversible Binding of Nanoparticles to Polymeric Surfaces

Reversible and irreversible binding of CdSe-nanoparticles and nanorods to polymeric surfaces via a strong, multiple hydrogen bond (= Hamilton-receptor/barbituric acid) is described. Based on ROMP-copolymers, the supramolecular interaction on a thin polymer film is controlled by living polymerization methods, attaching the Hamilton-receptor in various architectures, and concentrations. Strong binding is observed with CdSe-nanoparticles and CdSe-nanorods, whose surfaces are equipped with matching barbituric acid-moieties. Addition of polar solvents, able to break the hydrogen bonds leads to the detachment of the nanoparticles from the polymeric film. Irreversible binding is observed if an azide/alkine-“click”-reaction is conducted after supramolecular recognition of the nanoparticles on the polymeric surface. Thus reversible or irreversible attachment of the nanosized objects can be achieved

Organically modified mixed-oxide sol-gel films with complex compositions and pore structures

Films with polymodal porosity (macro-, meso- and micropores) as well as complex materials compositions (different metals, different organic groups) were prepared. First, self-assembled polystyrene spheres on glass slides were coated with a sol prepared from tetraethoxysilane, phenyl- or methyltriethoxysilane and ethyl acetoacetate-stabilized zirconium propoxide or titanium iso-propoxide in the presence of a non-ionic surfactant. Macropores were created by dissolving the polystyrene porogen. Subsequent calcination at different temperatures resulted in the sequential formation of meso- and micropores. Post-calcination treatment with phosphonic acids allowed the introduction of a second type of organic group

Titanium alkoxo oximates, with surfactant-like properties of the oximate ligands, as precursors for porous TiO2 and mixed oxide sol-gel films

Titanium alkoxo oximates with long-chain alkyl groups were used as sol-gel precursors for simultaneous deceleration of the reaction rates of Ti(OR)(4) and creation of porosity upon calcination due to surfactant-like properties. Both titania and hybrid silica-titania films with high surface areas were obtained. Extraction studies showed that only part of the employed oxime is coordinated, but both coordinated and non-coordinated oxim(at)e contribute to pore formation upon heat treatment. Sorption properties of silica-titania hybrid materials were studied by investigating temperature-programmed desorption of toluene