La presente invention concerne un convertisseur de couleur comprenant au moins une couche comprenant au moins un colorant fluorescent organique et au moins une couche de barriere ayant une faible permeabilite a l'oxygene.

Anisotropic surface modification of TiO2 nanoparticles was achieved applying a Pickering emulsion approach. TiO2 nanoparticles were prepared by sol-gel routes which allowed an excellent control over their size and morphology. The obtained colloids were further used as stabilizers in the formation of oil-in-water Pickering emulsion. For reasons of comparison, also commercially available titanium dioxide nanoparticles (Evonik AEROXIDE TiO2 P25) were used in the functionalization experiments. An organophosphorus coupling agent present in the oil phase coordinated to the surface of the anatase nanoparticles. In such a way an anisotropic surface modification of the particles was achieved which increased the stability of the Pickering emulsion. Spectroscopic studies revealed the presence of organophosphorus coupling agents which exhibited a covalent bonding to the surface of the particles. Thermogravimetric analyses confirmed a lower surface coverage of the particles modified in emulsion compared to those modified in suspension. Reactions of organophosphorus coupling agents containing an additional methacrylate group applying an organic monomer (methyl methacrylate) as the oil phase of the Pickering emulsion resulted in hybrid TiO2@polymer spheres. Spectroscopic characterization of the resulting particles revealed that the phosphonates were coordinated to the TiO2 surface and at the same time copolymerized with the MMA within the oil droplet. Morphological investigations of the isolated final product showed that the material was composed of polymer spheres with the stabilizing TiO2 nanoparticles on their surface.

Storage shells: The assembly of negatively charged graphene oxide and positively charged oxide nanoparticles by electrostatic interactions, and subsequent chemical reduction, leads to metal oxides encapsulated in flexible and ultrathin graphene shells (see picture). These electrochemically active nanoparticles show a remarkable lithium storage capacity, with an excellent cycle performance. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Polysiloxane-PEO hybrid polymers were used as precipitation environments for La(OH)3 nanoobjects.

Polysiloxanes in combination with metal oxides show interesting properties as nanocomposites for optical or medical applications. The formation of covalent connections between the metal oxide and the polysiloxane is an important method to overcome phase separation between the two components, but it also can have an influence on the morphology of the final materials. In this contribution we report a method for the synthesis of hybrid materials based on polysiloxanes and various metal oxides in which both components are tightly connected to each other. Alkoxysilane modified polysiloxanes were obtained by hydrosilation reactions between vinyl triethoxysilane and poly(dimethylsiloxane-co-methylhydrosiloxane) (PDMS-co-PMHS). The thus functionalized polymers were used in a sol-gel process applying Stöber conditions and hybrid nanoparticles were obtained. Following the same pathway, different metal alkoxides (M(OR)4; M = Ti, Zr; R = ethyl, isopropyl) were coordinated to allyl acetoacetate (AAA) and the resulting complexes were applied in a hydrosilation reaction with PDMS-co-PMHS. Metal oxide hybrid nanoparticles were obtained through a sol–gel process.

Well-defined complexes of Ti and Zr alkoxides and beta-keto ester ligands carrying polymerizable double bonds were copolymerized with methyl methacrylate applying atom transfer radical polymerization. The structure and the morphology of the obtained hybrid polymers were investigated using NMR, FT-IR, and size exclusion chromatography. All methods revealed an incorporation of both comonomers in the polymer backbone. NMR,and FT-IR analyses demonstrated that after polymerization the chemical linkage between the metal alkoxides and the organic macromolecules was preserved. The alkoxide-containing macromolecules were used as precursors in the formation of metal oxide-containing nanocomposites applying the sol-gel process. The decomposition temperature of the final nanocomposites increased depending on the chemical composition of the materials. Small-angle X-ray scattering investigations revealed a short-range order for the polymers containing Ti-alkoxides which disappeared after carrying out the sol-gel process due to the hydrolysis of the well-defined complexes. Transmission electron microscopy showed the formation of amorphous metal oxide nanoparticles inside the polymer network with diameters of a few nanometers. The particles were highly dispersed due to the low mobility of the alkoxides in the matrix during the sol-gel process.

Hybrid TiO(2)-polysiloxane nanoparticles as well as hybrid TiO(2)-polysiloxane gels were prepared and characterized applying solvent-induced aggregation effects of titanium alkoxide-modified polysiloxane block copolymers. The functionalized polymers were prepared by the covalent attachment of coordination sites that allow the binding to metal alkoxides (M(OR)(4); M = Ti; R = ethyl, butyl, isopropyl). Composition and structure of the hybrid polymers were investigated by NMR and FT-IR spectroscopy. In a second step the metal-alkoxide functionalities were hydrolyzed to form the respective metal oxides. Depending on the solvent in which the hydrolysis took place, hybrid nanoparticles or gels were obtained as a result of the different compatibility of the polysiloxane blocks towards the polarity of the solvents. The formed materials were investigated by NMR, FT-IR, atomic force microscopy (AFM), electron microscopy, and dynamic light scattering (DLS).

The use of various phosphonic acid derivatives – some of which contain polymerizable groups – as surface modifying agents for nanoparticles was studied both in-situ during the synthesis of lanthanide-based (Ln = Nd, Eu, Yb) nanoparticles at room temperature as well as in a separate step after the particle preparation by a hydrothermal method. In the single-pot in-situ method the phosphonic acid esters served as growth-limiting agent during particle formation leading to small nanoparticles with a size of only a few nanometers as determined by dynamic light scattering as well as transmission electron and atomic force microscopy. Free phosphonic acids as well as their silyl esters were used to modify the hydrothermally prepared neodymium hydroxide nanorods which had diameters of approx. 20 nm and a length ranging up to a few micrometers. The surface modification was confirmed by infrared spectroscopy and thermogravimetric analysis.

Hybrid inorganic-organic polymers were prepared applying poly(ethylene oxide) (PEO) crosslinked polysiloxanes as a matrix for the precipitation of metal or metal oxide nanoparticles. Polysiloxanes as flexible and hydrophobic polymer backbones were crosslinked with end-group functionalized PEO by using Pt-catalyzed hydrosilation reactions. Systematic variation of the chain length of the different components resulted in tunable matrices with adjustable hydrophilic regions. The chemical nature of the polysiloxane backbone and the thermal stability of the crosslinked polymer system facilitated nanoparticle preparation through different mechanisms. The crosslinked hybrid polymers were infiltrated with solutions of lanthanide salts, cobalt carbonyl or HAuCl 4 allowing the application of three different chemical methods (hydrolysis, thermal decomposition, reduction) for nanoparticle preparation. FT-IR, SEM and TEM analyses were used to characterize the insoluble hybrid systems.

Metal-alkoxides containing polymerizable groups are regularly used as precursors for inorganic–organic hybrid materials applying the combination of the sol–gel process and organic polymerizations. Here we report the synthesis of acetoacetoxy derivatives that are linked to methacrylate groups via alkyl chains of different chain length. The coordination of the resulting molecules to titanium- and zirconium-alkoxides (M(OR)4; M = Ti, Zr; R = ethyl, butyl, isopropyl) was investigated applying NMR and FT-IR measurements. The results were related to structural data of the dinuclear complex [Ti(O i Pr)3(EAA)]2 (HEAA: ethyl acetoacetate) which was obtained by single crystal X-ray diffraction. The study revealed that the β-keto ester groups acted as chelating ligands in all cases and thus polymerizable coordination compounds were formed. However, NMR analyses in solution showed that transesterification of the methacrylic-type monomers occurred even at mild conditions as a side reaction in a ratio which was found to be dependent on the type of metal alkoxide used.