Polymerization-induced phase separations and concurrent sol-gel transitions in the hydrolysis and polycondensation of alkylene-bridged polysilsesquioxane system resulted in the formation of co-continuous macroporous gels. Gel morphology with co-continuous macropores and micrometer-sized gel skeletons was obtained in the composition region containing much higher amount of water compared with the case with other alkyltrialkoxysilane sol-gel systems. A narrow pore size distribution and high volume fraction of macropores were obtained in the median size range from few micrometers down to 0.1μm.

Optical properties of metal and semiconductor nanoparticles are sensitively dependent upon electronic coupling between the individual particles. In another work, we have demonstrated the ability to regulate inter-particle electronic coupling between metal nanoparticles based on the solution-phase properties of the dendrimers used to encapsulate and stabilize the particles. Here, we attempt to apply the knowledge derived in those studies of metal nanoparticles to understand the optical response observed in dendrimer-stabilized CdS quantum dots. Absorption and photoluminescence measurements have been combined with TEM to determine if dendrimerrelated aggregation phenomena affect optical response in these systems. The results show that dendrimer-stabilized CdS nanoparticles exhibit quite different aggregation behavior from the analogous metal nanoparticles. In direct contrast to the metal systems, the dendrimer-stabilized CdS nanoparticles tend to flocculate at low pH and are most stable at high pH. The degree of protection offered at high pH is dependent on the terminal functional groups of the dendrimer. Carboxylated dendrimers give higher protection than aminated dendimers and yield significantly higher luminescence efficiencies. The results challenge our prior conclusions regarding aggregation mechanisms in dendrimer nanocomposites and will provide important insight for future efforts to incorporate these nanoparticles into photovoltaic or luminescent devices.

We here report the synthesis of ordered ceramic materials with hierarchy produced by an in-situ mineralization of ordered wood cellular structures with surfactant-templated sol-gel at different pH. At low pH, a silicic acid is coated onto inner surface of wood cellular structure and it penetrates into pores left, where degraded lignin and hemicellulose are leached out, to form a positive replica, while at high pH the precipitating silica particles due to fast condensation clog the cells and pit structures to form a negative replica of wood. The calcined monoliths produced in different pHs contain ordered wood cellular structures, multi-layered cell walls, pits, vessels well-preserved with positive or negative contrasts, respectively. The surfactant-templated mineralization produces ordered hexagonal nanopores with 20Å in the cell walls after calcination.

A direct synthetic method has been developed to produce hybrid materials composed of polymeric matrices infiltrated with layered inorganic particles. Magnesium chloride hexahydrate and (3-aminopropyl)triethoxysilane (ATES) were employed to produce lamellar organicallymodified magnesium silicate clays with structures analogous to the inorganic 2:1 phyllosilicates. Amino-functionalised Mg-phyllosilicates were prepared inside a poly(ethylene oxide) (PEO) matrix under quasi non-aqueous conditions. Nanostructured PEO-organoclay composites in bulk and films have been prepared with different layered inorganic particle loadings. X-ray diffraction patterns recorded showed for all samples reflections characteristic of crystalline PEO and layered magnesium organosilicate. Increasing the inorganic content of the composites resulted in the disappearance of the X-ray reflections characteristic of crystalline PEO.

Depth profiled positronium annihilation lifetime spectroscopy (PALS) has been used to probe the pore characteristics (size, distribution, and interconnectivity) in thin, porous films, including silica, organic and hybrid films. PALS has good sensitivity to and resolution of all pores (both interconnected and closed) in the size range from 0.3 nm to 30 nm, even in films buried under a diffusion barrier. In this technique a focussed beam of several keV positrons forms positronium (Ps, the electron-positron bound state) with a depth distribution that depends on the selected positron beam energy. Ps inherently localizes in the pores where its natural (vacuum) annihilation lifetime of 142 ns is reduced by collisions with the pore surfaces. The collisionally reduced Ps lifetime is correlated with pore size and is the key feature in transforming a Ps lifetime distribution into a pore size distribution. In hybrid films made porous by a degradable porogen PALS readily detects a percolation threshold with increasing porosity that represents the transition from closed pores to interconnected pores. PALS is a non-destructive, depth profiling technique with the only requirement that positrons can be implanted into the porous film where Ps can form.

In this report we introduce new types of organic-inorganic hybrid mesoporous materials, in which organic and inorganic moieties are distributed homogeneously at the molecular level in the framework, forming a covalently bonded network. Possessing unique surfaces on which both organic and inorganic components are exposed, these materials are expected to have applications in various areas as catalysts, adsorbents and separators, and as hosts for nano-cluster synthesis. The hybrid mesoporous materials showed not only unique surface properties but also unique structural features in micron- or angstrom-scales. Mesoporous materials containing ethylene groups in the main framework formed a variety of particle morphologies of hexagonal rod, spherical, and decaoctahedral shapes in the sizes of 1-10 μm. Mesoporous material containing phenylene groups showed novel crystal-like 7.6 Å periodicity in the pore walls. The mesoporous material has periodically arranged hydrophobic-hydrophilic surfaces, which is a great advantage for use as catalyst and host material for inclusion chemistry.

Organic-inorganic hybrid materials were synthesized for use of lithium battery electrode by two strategies: 1) core-shell strategy for tri-dimensional transition metal oxide and 2) intercalation strategy for bi-dimensional (lamellar) transition metal oxide. We choose conductive polymers as an organic component for high electric conductivity and 3d-transition metal oxides as an inorganic counterpart for large capacity and processibility. Polypyrrole/maghemite and poly(3,4-ethylenedioxythiophene) (PEDOT)/vanadium pentoxide hybrids will be presented and compared with their pristine materials for core-shell and intercalation strategies, respectively. Polypyrrole/maghemite showed an enhanced electrochemical reversibility and capacity up to ∼270 mAh/g in the potential range between 1.3 and 4.3 V vs. Li at 8 mA/g. PEDOT/vanadium pentoxide also exhibited improved reversibility and capacity up to ∼330 mAh/g at 15 mA/g between 2.0 ∼ 4.4 V vs. Li on the second discharge. XRD, IR, electron microscopy, XPS and Xray absorption spectroscopy were used to characterize the samples, and to examine oxidation state of the transition metals, doping character of the polymer and the nature of interaction between the polymer and the transition metal oxides.

Organically-modified silicate (Ormosil) films have been found to provide good corrosion resistance for metal substrates and are potential replacement systems for hexavalent chromiumbased conversion coatings. Significant enhancement in corrosion resistance properties were observed upon addition of sub-micron to micron-sized particles (TiO2, Al2O3, SiN, TiN) to the Ormosil coating as determined using accelerated salt spray and electrochemical analysis. Rcorr values derived from potentiodynamic polarization curves were found to increase from 1520 to (3800 - 4680) kΩcm2 upon addition of various concentrations of TiO2, Al2O3, SiN or TiN particles to the Ormosil thin film. Similarly, Epit values were found to range from +0.2 V for the non-doped Ormosil to (0.6 – 1.9) V for particle-doped Ormosil thin films.

Interactions between the dye Red 17 (4-(amino-N, N-diethanol)-2-methyl-4'-nitroazobenzene) having nonlinear optical (NLO) properties and metallo-organic sol-gel precursors M(OR)n (M = Ti, Zr, Si and Sn; R = CnH2n+1) have been investigated by means of UV-VIS spectrophotometry and liquid state NMR (1H, 29Si and 119Sn) techniques. The presence of titanium, zirconium or tin alkoxides make strong modifications in the UV-VIS absorption spectrum of the Red 17 in solution. On the contrary, when the Red 17 is grafted to alkoxysilyl groups, only minor changes were observed. The resulting bathochromic shift of about 30 nm observed with transition metal or tin alkoxides was found to be due to Lewis acid-base type interactions between the Red 17 and the metallic centre.

Recently microporous and mesoporous materials were found to be particularly suitable for a new type of applications in the mechanical field. This paper reports experimental features about the dissipative forced intrusion of water in highly hydrophobic mesoporous materials: this phenomenon can be used to develop a new type of dampers and/or actuators. Silica-based materials behavior was investigated. Among them, MCM-41 exhibit original and interesting properties towards the potential developments of dampers and appear to be of great interest for the comprehension of energy dissipation mechanisms.

O-aminobenzenesulfonic acid is incorporated between the sheets of Cu2Cr(OH)6Cl. H2O hydrotalcite-type materials. After heating, a narrow ESR signal characterisitic of conductive polymer behavior is observed for the hybrid phase. The reaction of polymerization fails in absence of the confinement supplied by the LDH host structure and of air atmosphere. The nanocomposite presents an electrochemical behavior in agreement with the presence of large polyanilinesulfonate (PAniS) units, whereas the electropolymerization gives rise first to the formation of dimers. Spin density is found to be greater with the electropolymerization after few cycles than after the heat treatment.

Fluorescence spectroscopy has been used to study the miscibility of methyl silsesquioxane (MSSQ)/poly(methyl methacrylate-co-dimethylaminoethyl methacrylate) [P(MMA-co-DMAEMA)] hybrid nanocomposites, which are useful in fabricating the next generation of spin-on, ultra-low dielectric constant materials in the microelectronic industries. In this work, we have attached the pyrene group into the PMMA side chains. MSSQ with different amount of initial -SiOH (silanol) endgroups are used to study the effect of endgroup functionality on the phase separation behavior of the hybrid nanocomposites. Pyrene excimer fluorescence results reveal that MSSQ is miscible with P(MMA-co-DMAEMA) only up to 6 wt% P(MMA-co-DMAEMA) loading level, thus establishing an upper limit on local miscibility with MSSQ. As the P(MMA-co-DMAEMA) loading level increases, the excimer to monomer ratios also increase, suggesting that the MSSQ/P(MMA-co-DMAEMA) hybrid nanocomposites move toward greater immiscibility. This ratio approaches that of the neat polymer for domain sizes > 5 nm (SAXS, SANS). The fluorescence results also show that, the lower the amount of initial silanol groups in MSSQ, the greater the immiscibility of the MSSQ and porogen, which ultimately translates into larger pores upon porogen burnout.

Methacrylate-substituted tetranuclear tantalum, zirconium and titanium oxide clusters (Zr4O2(OMc)12, Ti4O2(OPri)6(OMc)6, and Ta4O4(OEt)8(OMc)4) were prepared by reaction of the alkoxides with methacrylic acid. The clusters were then polymerized with methyl methacrylate as co-monomers in different molar ratios (0.5–2 mol% of the functionalized cluster). In the resulting inorganic-organic hybrid polymers, the clusters crosslink the polymer chains very efficiently. The physical properties and structural features of the hybrid polymers, investigated by their swelling behavior, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), 13C MAS NMR and impedance spectroscopy, exhibit a clear dependence on the cluster portion in the polymer and on the cluster type.

The design, synthesis and stimuli-responsive behavior of organically-modified silicates (ORMOSILS) is reported. The ORMOSILS behave as ‘smart’ materials by undergoing structural changes at the molecular level to respond to changes in environmental variables. Typical responses in the form of swelling/shrinkage with respect to changes in temperature, pH, and salt concentrations are presented. Finally, the nature of predominant mechanism responsible for the sol-gel's behavior towards combined stimuli of high temperature and low pH is discussed.

Mesostructured TiO2-surfactant hybrid xerogels and thin films are prepared by Evaporation-Induced Self Assembly (EISA). These organized structures are reproducibly formed through cooperative self-assembly between hydrophilic Ti-oxo species and a micellar template after selective solvent evaporation from ethanol/HCl/H2O media. The construction of these networks is tailored by tuning the hydrolysis-condensation of the metallic cations with the self-assembly of the organic counterparts (“hydrophilic matching” approach). The hybrids present hexagonal mesostructure (p6m). The formation kinetics of the mesophase is followed by SAXS, interferometry and mass spectrometry (MS) analysis of the vapor phase. An adequate thermal treatment of the organized hybrids leads to high surface (150-400m2 g-1) phosphorus-free mesoporous titania films or powders, with walls containing anatase nanocrystallites. This approach can be successfully extended to other non-silicate based meso-structured materials.

Electron or hole conductivity in conjugated polymers provided their initial thrust, but conductive polymers also display interesting electrochemical properties which constitute the base for their application in different types of electro-ionic devices. A further step in the development of functional materials based on conductive polymers is provided by the design of hybrid materials. In hybrid organic-inorganic materials based on conductive polymers, the electroactivity of molecular doping species or other inorganic components is added to that of the polymers themselves, leading to a whole new spectrum of hybrid materials that allow for the harnessing and control of the electrochemical properties of molecular species and put them to work in the development of all sorts of functional materials and devices, from sensors or catalysts to rechargeable lithium batteries, supercapacitors or photoelectrochemical devices. In this chapter we present several examples of this type of functional materials, their synthesis, properties and applications. We will present a general overview of this field and will discuss in some detail the design of insertion electrodes based on conducting polymers and hybrid organicinorganic materials based on them, analyzing their peculiar ion-inserting mechanisms and their possible application in energy storage devices.

We report in this paper how electrospray mass spectrometry (ESMS) and nanospray mass spectrometry (NMS) are promising for analyzing precursors and nano-scale semiconductor (IIVI) materials up to 1.5 nm and mixed valence clusters (Co/Cd). We show that both ion modes in ESMS and NMS provide insight concerning the structure analysis, the composition and the stability of these materials.

Microencapsulation provides protection and sustained or controlled release of active core agents. The sol-gel process has opened up a new way for encapsulating oil droplets within an inorganic capsule. Silica microcapsules were prepared in silica precursor-oil mixtures/NH4OH water microemulsion system. In this step, the formation of capsules incorporating oil depended strongly on the type of silica precursor. A spherical silica microsheres were only obtained when oligomer, synthesized by the hydrolysis and co-condensation of equiweight of TEOS (tetraethylorthosilicate) and MTMS (methyltrimethoxysilane), was used as the wall materials. The particles size of silica microcapsules was in the range of 1 ∼ 100 μm, depending on processing parameter such as a shear rate and O/W ratio etc. In controlled release system, the shell porosity is important to give an appropriate permeability, corresponding to the release rate. The pore structure, responsible for permeability, was adjusted by doping alkyl silane, and investigated with nitrogen sorption measurement.

Silica mesoporous thin films have been synthesised with a self-assembling process employing cetyltrimethylammonium bromide as the organic template and tetraethyl orthosilicate as the silica source. Mesoporous films with Pm3n cubic phase phases have been obtained and the films have been thermally treated in air with a progressive heating schedule from asdeposited up to 1000°C. The evolution of the microstructure has been studied with transmission Fourier transformed infrared (FTIR) spectroscopy.

FTIR spectra of the as-deposited films have shown the presence of cyclic species, which at temperatures larger than 350°C have been no more observed. In the 1000-1300 cm-1 region several overlapped absorption bands have been detected. In particular, the pair LO3-TO3, the cyclic species absorption bands and the pair LO4-TO4 have been resolved. These last bands, in particular, are associated with disorder-order transitions in the silica microstructure. These disorder-induced optical modes are due to the large interface area and related to bond strains.

The evolution of the bands in the 1000-1300 cm-1 region has been followed with the Berreman configuration, performing the transmission FTIR analysis at 45° with respect to the normal incidence angle. The LO3 band, which in silica sol-gel films is indicative of the network condensation and is activated by scattering of the light in the pores, was resolved as a single sharp band from 250°C.

The magnetic and structural properties of sol-gel derived organic/inorganic nanocomposites doped with Fe(II), Fe(III), Nd(III) and Eu (III) ions are discussed. These hybrids consist of poly(oxyethylene)-based chains grafted onto siloxane nanodomains by urea cross-linkages. Small angle X-ray scattering data show the presence of spatial correlations of siloxane domains embedded in the polymer matrix. The magnetic properties of rare-earth doped samples are determined by single ion crystal-field-splitted levels (Eu3+ J=0; Nd3+ J=9/2) and the small thermal irreversibility is mainly associated to structural effects. Fe2+-doped samples behave as simple paramagnet with residual antiferromagnetic interactions. Fe3+-doped hybrids are much more complex, with magnetic hysterisis, exchange anisotropy and thermal irreversibility at low temperatures. Néel temperatures increase up to 14K for the highest (∼5.5%) Fe3+ mass concentration.