The use of organosilica sol-gels for controlled in-situ formation of metal nanoparticles is investigated. The use of an organically-modified alkoxysilane precursor provides chemically interacting nanopores for the sequestration and binding of metal ions followed by chemical reduction to form metal nanoparticles. The sol-gel matrix acts as a structural template to enable growth of the metal nanoparticles within its porous silica framework, and prevents clustering to form precipitate. Furthermore, simple redox chemistry is used to convert pre-formed copper nanoparticles in the sol-gel matrix into silver and gold nanoparticles. A particularly important aspect of this synthesis method is that all the reaction chemistry is performed under ambient conditions. The particles are characterized by high resolution transmission electron microscopy for their sizes and size distribution. The elemental composition of the particles is determined by energy dispersive X-ray analysis.

Polyimide-clay nanocomposites were prepared by blending 2.5 and 5 wt.% of PGV (Na+-montmorillonite) and two organically modified PGV (PGVC10COOH, PGVC12) with a methanol solution of PMR-15 precursor. DMA results showed a significant increase in the thermomechanical properties (E' and E'') of 2.5 wt.% clay loaded nanocomposites in comparison with the neat polyimide. Increasing the clay loading to 5 wt.% degraded these properties. Higher Tgs were observed for 2.5 wt.% nanocomposites compared to the neat polyimide. A lower CTE was observed only for the PGV/PMR-15 nanocomposite. Flexural properties measurements for the 2.5 wt.% nanocomposites showed an improvement in the modulus, strength and elongation. This trend in the tensile properties was not observed for the 5 wt.% nanocomposites.

Sugar-based amphiphilic molecules are used as templates in the sol-gel processing of thin silica films. The films are prepared relying on solvent evaporation-induced self-assembly during dip-coating in a humidity controlled chamber. Different surfactants, such as the commercially available alkyl glycosides (e.g. n-octyl β-D-glucopyranoside and n-dodecyl β-D-maltopyranoside), are compared with respect to their ability to cooperatively self-assemble in alcoholic silicate solutions. The larger polar headgroup (maltose) decreases the critical packing parameter and thus beneficially influences the formation of a favorable hexagonal phase over the lamellar phase, which is formed with the glucose-based surfactant. The inorganic-organic composite films show a strong influence on the humidity during their synthesis. For nonstructured films, ordering could be achieved by exposing the as-deposited films to a high humidity for several hours. The final material is characterized by X-ray diffraction, nitrogen sorption and solid state NMR techniques.

Silicon-boron and silicon-aluminum imide gels were prepared by catalyzed ammonolyses of the precursors 2,4,6-tris[tris(dimethylamino)silylamino]borazine, {[(CH3)2N]3SiNH}3B3N3H3, 1, 2-(dimethylamino)4,6-di[tris(dimethylamino)silylaminoborazine, {[(CH3)2N]3SiNH}2B3(NMe2)N3H3, 2, and tris(dimethylaminosilylamino)-(tetrahydrofuran)alane, C4H8O)Al[NHSi(NMe2)3]3, 3, respectively. All the gels exhibited mesoporous structures with high surface area.

A new method has been developed for the synthesis of shaped-controlled bridged silsesquioxanes by the acid hydrolysis of urea-derived silylated precursors. This method is based on the ability of the hydrogen bonds of the urea groups to organize the molecules in a supramolecular architecture and provides after hydrolysis a new access to hybrid materials with controlled morphologies. A chirality transcription from a molecular precursor to a hybrid solid has been achieved. A right- and a left-handed helices have been obtained respectively from the chiral (R,R)- and the (S,S)-enantiomers of the diureido derivatives of trans-diaminocyclohexane. In a related way, a long range ordered hybrid solid has been obtained. Long carbon chain as spacer between the urea groups of the precursor affords lamellar hybrid silicas.

The CEA/DAM megajoule-class pulsed Nd:glass laser devoted to Inertial Confinement Fusion (ICF) research is requiring 7,000-m2 of coated area onto 10,000 optical components. Among these different optics, two specific examples of applied sol-gel chemistry will be described. First one is dealing with the 240 44-cm square cavity-end mirrors needing to be highly-reflective (HR)-coated onto deformable substrates. Such large dielectric mirrors are using interference quaterwave stacks of SiO2 and ZrO2-PVP (PolyVinylPyrrolidone) thin films, both starting from sol-gel colloidal suspensions (sols). The ZrO2-PVP high index layer is a nanohybrid material prepared from mixing nanosized-zirconia suspension with a transparent polymer solution (PVP). The oxide/polymer ratio of the hybrid system has been optimized regarding refractive index value and laser damage threshold. UV-curing of the nanohybrid has enabled optical coating stacking up to 20 layers, achieving 99% minimum reflection over the whole coated surface. FT-IR spectroscopy has been used to highlight particles/polymer chemical interactions and also polymer modifications under UV-irradiation.

Second example is concerning development of a silica-based hybrid material to protect silvercoated light reflector used in laser pumping cavity. These metallic reflectors require a protective overlayer in order to preserve high-reflectivity front surfaces for long periods of operation under intense broadband flashlamp light and typical airborne contaminants. The so-called ormosil coating has been optimized in term of thickness and composition to enhance silver resistance to oxidation and tarnishing under UV-irradiation, to protect silver layer from clean-room cleaning procedure, to withstand 10,000 flashlamp glow-discharges exposure with the lowest possible change in the reflection value. To fulfil these requirements, the developed hybrid sol-gel material acts as an oxidation dense barrier, is chemical-resistant, is durable and remain transparent in the 400-1000nm wavelength range. Moreover, the sol-gel process allows industrial protective coating deposition onto large-sized and multi-shaped reflectors. These new protected reflectors will need to be replaced much less often than reflectors employed in current solid-state lasers, ensuring both higher performance and lower operating costs.

Environmental laws concerning the water are becoming more and more stringent year after year in European Union (AT2950 France, Legge Merli in Italy). The classical silver halide photoprocessing requires at least 3 steps which are the development, the fixing and the wash. The washing step uses a large amount of water which is discarded in the sewer. By July 2000 a new French regulation imposed that the volume of wash water has to be divided by 5 and the nature of pollutants (silver in different species) has to be maintained below 1 mg/L. The Kodak Water Saving Treatment System has been designed to help our customers to be in compliance with the law. This system has two functions, the release of a biocide cocktail and the trapping of silver. Two aluminosilicate gels (imogolite -like material) allow the treatment to occur, the first one releases biocides in the water flow and allows the processor to remain clean, the second one which is an hybrid organic-inorganic composite (imogolite modified by a controlled hydrolysis of a mercaptoalkyl silicium alkoxide) allows to trap silver. These gels are extremely robust versus time and chemical environment (pH). This paper will describe the synthetic way, the gel system characterization (Raman) and the obtained performances in various configurations after one year on the market. Other applications of these hybrid organic -inorganic composites in photographic fields will be also discussed.

Use of organosilanes as hybrid systems is of increasing importance for their promising applications in the optical field. Considerable attention has been paid to the study of the inorganic network. However, poor information concerning the organic part involved in the solgel process is available. This is yet a fundamental requirement for optical applications where homogeneity at molecular scale is essential. Taking into account the specificity of the sol-gel medium, characteristics of the organic part have to be adapted with the view of optimizing the properties of the final material. Hybrid material used in this study consisted of organosilane precursor with methacrylate functions, titanium isoproxide, methacrylic acid and photoinitiator. The polycondensation of the inorganic component was achieved sequentially and simultaneously with the photopolymerization of the organic one to provide a mutually interpenetrating network. Polymerization in the UV range presents the advantages of fast-curing at temperature compatible with fragile substrates and spatio-temporal selectivity of the reaction. Characteristics of the photopolymerization process taking place in hybrid sol-gel materials were investigated by UV and Real Time FTIR spectroscopy. Besides the study of the organic network, NMR investigations led information relative to the inorganic network formation during the sol maturation. The whole results provide insights into the optimization of the photochemical step. Indeed, it was demonstrated that titanium components added as passive components to increase the refractive index of the layer, can induce polymerization under a medium pressure mercury arc lamp irradiation. In addition, mix photoactive systems involving an organic photoinitiator and titanium components were investigated and led to a better efficiency for the photoinitiation. Final materials with higher conversion ratio of the methacrylate function and requiring shorter irradiation times were achieved.

Double hydrophilic block copolymers were used to control the growth of inorganic particles and directly prepare hybrid colloidal suspensions. Colloids of metal hydrous oxides were obtained by forced hydrolysis of metal ions in presence of the copolymers. The block copolymers contain a metal-complexing polyelectrolyte block and a stabilizing neutral block. The role of the first block is to ensure a controlled growth of the inorganic phase, while simultaneously, the second block ensures the colloidal stabilization. Phase diagrams presenting the conditions under which precipitation is inhibited are established. The nanoparticles are then characterized in terms of sizes, morphologies and surface charges. The main parameters controlling the size were identified: the copolymer-to-metal ratio and the metal prehydrolysis ratio. The synthesis steps were characterized. First, a key step of induced micellization of the hydrophilic copolymers leads to hybrid core-shell assemblies. The second step consists in mineralization of the micellar core. The suspension polycondensation leads to hairy particles whose morphologies depend on the nature of the metal and on synthesis parameters.

A new approach for depositing polymer/inorganic hybrid films using gas phase deposition technology has been developed and is the focus of this work. These films combine the high hardness and scratch resistance of inorganic SiO2 films with properties such as flexibility and toughness usually associated with softer polymeric films. The gas phase deposition process eliminates several of the key problems associated with the traditional wet chemical preparation of hybrid materials namely, a reduction in process steps and the elimination of harmful solvents from the process. In addition, gas phase deposition processes generate inherently denser materials then wet chemical processes eliminating post deposition annealing procedures that may damage the substrate. In this study, films are deposited on polycarbonate (PC) and silicon substrates using a novel plasma reactor. In this system, two gas streams, activated by separate plasmas, are combined to form a hybrid thin film.

Films are grown from the precursor Tetraethoxysilane (TEOS), 1,2 Bis(trimethylsiloxy)ethane (TMSE) and Tripropylsilane (TPS) evaluated with respect to mechanical, chemical and optical properties, using scratch resistance (Taber abrasion), Methyl Ethyl Ketone (MEK), adhesion and visible transmission measurements. Structural and chemical properties of the deposited films are determined using IR spectroscopic measurements coupled with spectroscopic ellipsometry. The process chemistry and mechanisms are studied using in situ mass spectroscopy, in situ FTIR and spectroscopic ellipsometry.

A novel synthetic pathway to obtain collagen-silica biohybrids using a co-gelation process is described. Concentration control of the inorganic and organic precursors leads to various morphologies. Of special interest is the possibility to obtain, through collagen templating, silica fibres that are maintained after protein removal.

High molecular weight polysilsesquioxanes with carboxylate functionalities were prepared by sol-gel polymerization of organotrialkoxysilanes bearing tert-butyl ester groups. Trialkoxysilyl-containing monomers of the type (RO)3Si(CH2)3C(O)OtBu (R = Me, Et) were prepared by hydrosilation of the corresponding vinylic tert-butyl esters CH3CHCH2C(O)OtBu. Acid- or base-catalyzed polymerization of the monomers leads to very high molecular weight polymers with relatively narrow polydispersities. The polymerization results in complete condensation of the alkoxy groups while the tert-butyl ester functionality remains fully intact. Partial or full deprotection of the tert-butyl group can easily be achieved to yield the corresponding carboxylic acid polymers. The ester and carboxylic acid functionalities of these new materials allow for their potential use in a variety of applications such as scavenging of heavy metals.

Organosilica powders with uniformly distributed bridging benzene groups have been synthesized from the condensation of bis- or tris-(triethoxysilyl)benzene in the presence of cetyltrimethylammoniumbromide. The syntheses were performed under strong acidic conditions and the organic groups were always incorporated without cleavage of the Si-C bonds as indicated by solid state MAS NMR studies. Depending on the nature of the precursors, materials with different ordering were obtained: a 2D-hexagonal (p6m) phase was formed from the 1,3-bis(triethoxysilyl)benzene, whereas the 1,4-bis(triethoxysilyl)benzene lead to a cubic Pm3n phase. The surfactant was removed either by solvent extraction or by controlled calcination, which did not affect the mesostructure of the materials.

Organisation of silicon-based hybrid materials prepared by sol-gel of (MeO)3-nSiMen-(C6H4)2-SiMen(OMe)3-n (n = 0, 1, 2) was evaluated and evidences the possibility of self-association of the macromolecular units at the sol step and reorientation process at the ageing step.

Hybrid materials like organo-phyllosilicates exhibit new properties which make them potential candidates for many industrials applications as rubber reinforcement, environmental barriers…. With this aim, a series of new layered inorganic-organic solids, with organic functionalities directly bonded to the inorganic sheets via the Si-C bond, were prepared by a template sol-gel synthesis under soft conditions (room temperature) using octyltriethoxysilane as the silica source, aluminum acetylacetonate as the alumina source, magnesium nitrate and sodium hydroxide. These hybrid materials belong to the 2:1 trioctahedral phyllosilicates family with inorganic compositions close to saponite. The ratio of Al (x) could be varied between 0 and 0.33. The x-ray diffraction patterns agree with a layers structure (presence of the (00l) peak series and the (060) peak). The high d001 spacing values (2.4-2.6 nm) can be related to the octyl chains present in the interlayer space. DRIFT and 13C NMR spectra indicate that the Si-C bonds are intact and siloxanes are fully hydrolyzed giving SiOAl and SiOMg bonds. 27Al and 29Si NMR were carried out in order to determine the repartition of the different elements in the layer: Al substitutes for Si in the tetrahedral layer and for Mg in the octahedral one. These results were determined by elemental analysis. The DTA-TG results show that the organic matter start to decompose in air above 250°C but its complete removal needs temperatures higher then 800°C. The aspect of the materials depends on the value of x; it varies from greasy, waxy, waxy powdery and finally powdery. The hydrophilicity of the solids depends strongly on the aluminum content.

The organic-inorganic (O-I) hybrid networks were prepared from well-defined O-I precursors (a) alkoxysilane-endcapped oligomers (ASO) and (b) epoxy-functional silsesquioxane (SSQO) clusters (EC). ASO precursors were crosslinked by sol-gel polycondensation and EC by the reaction of the epoxy groups with oligomeric diamine Jeffamine D2000. Formation, structure and mechanical properties of the networks were followed by SEC, NMR, SAXS and DMA. The O-I block copolymer network is composed of SSQO domains forming network junctions linked by an oligomer chain. Structure of the SSQO crosslink “points” ranges from compact polyhedral cages to large loose SSQO clusters in dependence on the precursor type and catalysis of the sol-gel process. Interphase interaction and mechanical properties of the O-I networks are discussed.

We present results on new periodic mesoporous organosilicas synthesized with 1,4-bis(triethoxysilyl)benzene (BTEB), 1,2-bis(trimethoxysilyl)ethane (BTME) and bis[3-(trimethoxysilyl)propyl]amine (BTMPA). The materials show high inner surfaces up to 830 m2/g and pore diameters in the range of 2.7 to 3.7 nm depending on the structure directing agent used. In case of BTEB as precursor and triblock copolymer Pluronic P123 as structure directing agent exceptional thick pore walls were obtained (7.2 nm). Characterization was carried out by P-XRD, nitrogen physisorption analysis, thermoanalytical methods and IR spectroscopy.

Hydrothermal syntheses and structural characterizations of some new open framework chalcogenides are described here. Open framework sulfides are often formed with supertetrahedral clusters as the basic structural building units, but it is demonstrated here that non-cluster based open framework sulfides can also be prepared. Selenides and tellurides have a stronger tendency to form non-cluster based materials. In some cases, it is possible to make materials in which the inorganic framework consists of at least two chalcogen atoms. Such a compositional diversity makes it feasible to tune structural, electronic, and optical properties.

The present work investigates the intrinsic photosensitivity of a family of poly(alkyl)(aryl)silanes and poly(hydridophenyl)silane for use in the development of photoimprinted waveguide devices. Limited testing of passive optical behavior (e.g. absorption, refractive index) and photosensitive response was performed for these materials in thin film form. It was determined that the materials exhibited dramatic photobleaching under 248 nm (KrF excimer laser) exposure. Based on a Kramers-Kronig analysis of the absorption changes, refractive index changes on the order of - 0.1 are estimated. Confirmation of this calculation has been provided via ellipsometry which estimates refractive index changes at 632 nm of -0.14 ± 0.01. In addition, embedded strips have been photoimprinted into the material to confirm waveguiding capacity of the films. Possible sources of photosensitivity in this material and its potential for application in various device configurations will be discussed.

In this work, diacetylenic-containing chiral lipid, 1,2-bis(10,12- tricosadiyonyl)-sn-glycero-3-phosphatidylcholine (DC8,9PC) was used simultaneously as a structure-directing template, “morphogen” and photoactive monomer to synthesize high aspect ratio helical tubules and ribbons consisting of polymerizable periodic mesostructured silica-lipid walls with a twisted lamellar architecture. Intercalation of silica in the ordered hybrid lamellar mesostructure significantly increased the photochemical reactivity of the diacetylenic moieties, such that eneyne conjugation became facile compared with non-mineralized tubules or tubules coated in a surface film of silica.