Showing papers by "Philippe Belleville published in 2006"

Hierarchically structured transparent hybrid membranes by in situ growth of mesostructured organosilica in host polymer

Abstract: The elaborate performances characterizing natural materials result from functional hierarchical constructions at scales ranging from nanometres to millimetres, each construction allowing the material to fit the physical or chemical demands occurring at these different levels. Hierarchically structured materials start to demonstrate a high input in numerous promising applied domains such as sensors, catalysis, optics, fuel cells, smart biologic and cosmetic vectors. In particular, hierarchical hybrid materials permit the accommodation of a maximum of elementary functions in a small volume, thereby optimizing complementary possibilities and properties between inorganic and organic components. The reported strategies combine sol-gel chemistry, self-assembly routes using templates that tune the material's architecture and texture with the use of larger inorganic, organic or biological templates such as latex, organogelator-derived fibres, nanolithographic techniques or controlled phase separation. We propose an approach to forming transparent hierarchical hybrid functionalized membranes using in situ generation of mesostructured hybrid phases inside a non-porogenic hydrophobic polymeric host matrix. We demonstrate that the control of the multiple affinities existing between organic and inorganic components allows us to design the length-scale partitioning of hybrid nanomaterials with tuned functionalities and desirable size organization from angstrom to centimetre. After functionalization of the mesoporous hybrid silica component, the resulting membranes have good ionic conductivity offering interesting perspectives for the design of solid electrolytes, fuel cells and other ion-transport microdevices.

Nanostructured Hybrid Solar Cells Based on Self-Assembled Mesoporous Titania Thin Films

Abstract: Nanocrystalline mesostructured porous titania thin films with optimized coating and thermal curing conditions have been prepared for the first time using spin-coating deposition technique. The X-ray diffraction (XRD) and the grazing incidence small-angle X-ray scattering (GI-SAXS) measurements revealed that the crystallization and diffuse sintering of amorphous TiO2 into anatase are simultaneously starting between 400 and 500 °C curing temperature, leading to a gridlike open-pore-shape transformation. The environmental ellipsometric porosimetry (EEP) measurements show that the 550 °C-cured TiO2 films exhibit a high porous volume (0.30 cm3 g-1), a large surface area (172 m2 cm-3), and a Young modulus of 1.05 GPa. All solid-state dye-sensitized solar cells (DSSC) based on nanocrystalline mesostructured TiO2 films and poly(3-octylthiophene) as hole conductor allow reproducible achievement of energy conversion efficiencies of about 0.52%. These values, obtained with thin TiO2 films (250 nm), are very promising.

Process for preparing a sol-gel solution and use of this solution to form a coating to protect a substrate having a metal surface

Abstract: The invention relates to a process for preparing a stable sol-gel solution. The solution may be used to form coating materials for metallic substrates, such as silver-based substrates for use in mirrors. The process includes the steps of preparing a sol-gel solution by bringing one or more molecular metal and/or metalloid precursors into contact with a medium comprising an organic solvent, adding at least one mercaptoorganosilane compound to the solution, hydrolyzing the solution obtained, and then adding one or more complexing agents to the solution.

Process For Producing a Coating Based on an Oxide Ceramic that Conforms to the Geometry of a Substrate Having Features in Relief

Abstract: The invention relates to a process for producing layers made of oxide ceramic that conform to substrates having features in relief comprising: a step of depositing on said substrate a layer of a sol-gel solution that is a precursor of said ceramic; a heat treatment step of said layer with a view to converting it to the ceramic; said steps being optionally repeated one or more times, characterized in that the sol-gel solution that is a precursor of said ceramic is prepared by a process successively comprising the following steps: a) preparing a first solution by bringing the molecular precursor or precursors of the metals intended to be incorporated into the composition of the ceramic into contact with a medium comprising a diol solvent and optionally an aliphatic monoalcohol; b) leaving the solution obtained in a) to stand for a sufficient time needed to obtain a solution that has a substantially constant viscosity; c) diluting the solution obtained in b) to a predetermined amount with a dial solvent optionally identical to that from step a) or a solvent that is miscible with the dial solvent used in step a).

Method of Preparing Stable Oxide Ceramic Precursor Sol-Gel Solutions Based on Lead, Titanium, Zirconium and Lanthanide(s) and Method of Preparing Said Ceramic

Abstract: The invention relates to a method of preparing a stable oxide ceramic precursor sol-gel solution based on lead, titanium, zirconium and lanthanide(s). The invention comprises the following successive steps consisting in: a) preparing a sol-gel solution by bringing a molecular lead precursor, a molecular titanium precursor, a molecular zirconium precursor and a molecular lanthanide precursor into contact with a medium comprising a diol solvent and optionally an aliphatic monoalcohol; b) leaving the solution thus obtained to stand for a sufficient period of time in order to obtain a solution having an essentially-constant viscosity; and c) diluting the solution obtained in the preceding step with a diol solvent identical to that used in step a or a solvent that is miscible with said solvent, at a predetermined rate. The invention can be used to prepare an oxide ceramic material comprising lead, a lanthanide metal, titanium and zirconium.

Procede de preparation d'une solution sol-gel et utilisation de cette solution pour constituer un revetement pour proteger un substrat a surface metallique

Abstract: L'invention a trait a un procede de preparation d'une solution sol-gel stable comprenant successivement les etapes suivantes : a) preparer une solution sol-gel par mise en contact d'un ou plusieurs precurseurs moleculaires de metal et/ou de metalloide avec un milieu comprenant un solvant organique; b) ajouter a la solution obtenue en a) au moins un compose mercaptoorganosilane ; c) hydrolyser la solution obtenue en b) ; d) ajouter a la solution obtenue en c) un ou plusieurs agents complexants choisis parmi les acides carboxyliques, les composes β-dicetones, les composes hydroxamates . Utilisation de cette solution pour constituer des materiaux de revetements de substrats metalliques, en particulier de substrat a base d'argent, tel que les miroirs.

Method for preparing a sol-gel solution and use thereof to form a metal substrate protective coating

Abstract: The invention concerns a method for preparing a stable sol-gel solution including the following successive steps: a) preparing a sol-gel solution by contacting one or more metal and/or metalloid precursors with a medium comprising an organic solvent; b) adding to the solution obtained at a) at least one mercaptoorganosilane compound; c) hydrolyzing the solution obtained at b); d) adding to the solution obtained at c) one or more complexing agents selected among carboxylic acids, β-diketone compounds, hydroxamate compounds. The invention also concerns the use of said solution for forming coating materials for metal substrates, in particular silver-based substrate, such as mirrors.

Revetement a base de mgo pour l'isolation electrique de substrats semi-conducteurs et procede de fabrication

Abstract: La presente invention se rapporte a un revetement inorganique a base d'oxyde de magnesium (MgO) destine a l'isolation electrique de substrats semi-conducteurs tel que du carbure de silicium (SiC), et a un procede de fabrication d'un tel revetement isolant Le procede de l'invention comprend les etapes de preparation d'une solution traitante d'au moins un organomagnesien hydrolysable et/ou d'au moins un sel de magnesium hydrolysable susceptible de former une couche polymerique homogene d'oxy-hydroxyde de magnesium par reaction d'hydrolyse-condensation avec de l'eau ; de depot de la solution traitante de l'organomagnesien hydrolysable ou du sel de magnesium hydrolysable sur une surface pour former une couche a base d'oxyde de magnesium ; et de densification de la couche formee a une temperature inferieure ou egale a 1000°C

Method of preparing oxide ceramic based on lead, titanium, zirconium and lanthanide(s)

Abstract: The invention relates to a method of preparing a stable oxide ceramic precursor sol-gel solution based on lead, titanium, zirconium and lanthanide(s). The invention comprises the following successive steps consisting in: a) preparing a sol-gel solution by bringing a molecular lead precursor, a molecular titanium precursor, a molecular zirconium precursor and a molecular lanthanide precursor into contact with a medium comprising a diol solvent and optionally an aliphatic monoalcohol; b) leaving the solution thus obtained to stand for a sufficient period of time in order to obtain a solution having an essentially-constant viscosity; and c) diluting the solution obtained in the preceding step with a diol solvent identical to that used in step a or a solvent that is miscible with said solvent, at a predetermined rate. The invention can be used to prepare an oxide ceramic material comprising lead, a lanthanide metal, titanium and zirconium.

Method for producing a ceramic oxide based coating conformable with the geometry of a substrate having raised designs

Abstract: The invention concerns a method for making conformable ceramic oxide layers on substrates having raised designs including: a step of depositing on said substrate a layer of sol-gel solution precursor of said ceramics; a step of heat treatment of said layer to transform same into ceramics; said steps being optionally repeated one or more times The invention is characterized in that the sol-gel solution precursor of said ceramics is prepared by a method including the following successive steps: a) preparing a first solution by contacting one or more molecular precursors of metals designed to be constituents of the ceramics in a medium comprising a diol solvent and optionally an aliphatic monoalcohol; b) allowing the solution obtained in a) to rest during sufficient time required to obtain a solution having a substantially constant viscosity; c) diluting at a predetermined proportion the solution obtained in b) with a diol solvent optionally identical to the one in step a) or a solvent miscible with the diol solvent used in step a)