We have discovered a novel chemisorption method using octadecyltrimethoxysilane (ODMS), titanium tetraisopropoxide (TTIP), water, and toluene [1] to form highly-ordered self-assembled monolayers (SAM) of ODMS. The SAMs were formed rapidly from the active solution even when it was kept for three months. The solution and layers were characterized by several methods. We propose a mechanism for the rapid formation of the ODMS-SAM.

Polyhedral oligomeric silsesquioxane (POSS) based materials are a class of organic/inorganic hybrid nanomaterials with many interesting properties. Recent experiments have demonstrated that self-assembly of tethered POSS nanocubes is a promising route to the synthesis of novel materials with highly ordered, complex nanostructures. Using a coarsegrained model developed for tethered POSS, we perform molecular simulations of POSS molecules tethered by short polymers to investigate how the novel architecture of these hybrid building blocks can be exploited to achieve useful structures via self-assembly. We systematically explore the parameters that control the assembly process and the resulting equilibrium structures, including concentration, temperature, tethered POSS molecular topology, and solvent conditions. We report preliminary results of lamellar and cylindrical structures that are typically found in conventional block copolymer and surfactant systems, but with interesting modifications of the phase behavior caused by the bulkiness and cubic geometry of the POSS molecules.

Polymer layered-silicate nanocomposites have attracted great attention due to their unique nanostructure and properties. The property of the nanocomposite is determined by the morphology of the nanocomposite. The typical morphologies of the nanocomposite are the intercalated and exfoliated nanostructures. In this study, the layered-silicate epoxy nanocomposite with different morphology can be controlled and achieved. The different morphology could include the intercalated nanostructure with the 15 Å increase of the interplanar spacing, the intercalated one with ∼150 Å increase of the gallery and fully exfoliated nanostructure.

The development and characterization of fluoroaryl functionalized organic-inorganic hybrid polymers for optical waveguide applications is presented. The materials are prepared from organoalkoxysilanes in a two-step process. The first step is the formation of the inorganic polysiloxane network by hydrolysis and polycondensation in order to obtain a soluble resin. This can be mixed with a photo initiator and applied onto a substrate as a photo-sensitive film. Micro patterns (waveguides with core and cladding) are then manufactured in a second step by exposure to UV-light through a mask. The polymers are characterized with respect to application in the fabrication of telecom optical waveguide devices. Thus, special attention is turned to optical losses in the telecom wavelengths at 1310 nm and 1550 nm as well as to refractive indices. During all stages of ORMOCER® preparation, structure-property correlations are deduced from presented characterization data.Various spectroscopic tools give an insight into network structures of polycondensate resins and cured hybrid polymer samples. 29Si-NMR in particular is used for the quantitative analysis of siloxane species. With the aid of molecular modeling, structural characteristics of oligomeric intermediates as determined by experiment are visualized. ORMOCER® resins with low optical losses of 0.28 dB/cm at 1310 nm and 0.42 dB/cm at 1550 nm, respectively, are prepared. Subsequent micropatterning by means of photolithography results in waveguide and other test patterns. A low optical loss of 0.51 dB/cm at 1550 nm is measured on a waveguide manufactured from a photopatternable fluoroaryl functionalized ORMOCER®.

Synthetic routes to high refractive index curable polyaromatics and halogenated aromatic functional silicone resins were developed. Organo silanes containing anthracenylmethyl-, naphthylmethyl- and iodobenzyl- groups were synthesized and used as precursors for the preparation of stable and soluble aryl-functional silicone resins. Alternatively the direct iodination of pre-formed aromatic-functional resins was investigated. We demonstrated the preparation of coatings with RI as high as 1.770 at 633 nm representing a significant optical enhancement as compared to traditional silicone and organic coatings.

Using reverse emulsion systems, we were able to trigger mineralization confined at an oil-water interface. In this process, the alcoxide silica precursor is dissolved in the oil continuous phase of the emulsion and diffuses through the bulk to the interface where it starts to hydrolyze and condense as soon as a certain concentration threshold is attained. The process takes place only in the presence of a water soluble surfactant inside the droplet. This surfactant leads to the presence of a controlled mesoporosity inside the silica shells. The obtained objects could be used in different encapsulation applications.

The X-ray powder diffraction spectrum of MoS2 with intercalated 5, 5, 7, 12, 12, 14-hexamethyl-1, 4, 8, 11-tetraazacyclotetradecane-1-acetic acid shows well-defined peaks as well as broad scattering. The X-ray scattering of this compound was simulated by generating model particles and calculating their X-ray scattering by evaluating the Debye sum. The match between the measured and simulated spectra was improved by trial-and-error. Matching the peak widths shows that the particles contain a total of about 6600 MoS2 units in about eight layers. The layers are oriented in the same direction (not turbostratic). However, they are translated randomly in the plane perpendicular to the stacking direction. In contrast to prior work on intercalation compounds, which considered various types of periodic reconstruction within the MoS2 layer, we obtain the best match with a non-periodic reconstruction in addition to a periodic superlattice. It involves dimer and trimer groupings of the molybdenum atoms with a random choice of centers. The intercalated tetraazamacrocycles form a two-dimensional glass. The effects of the key model assumptions on the calculated spectrum are demonstrated.

A new family of materials that synergistically combine the attributes of both organic and inorganic properties for use in organic light emitting diodes (OLEDs) is presented. The hybrid materials are based on 3-D inorganic cores of octavinylsilsesquioxanes (OVS). The resultant materials have high Tg's (120–210°C), are formed from minimal step/high yield reactions and readily available starting reagents, are monodisperse (PDI<1.1), can be highly purified via common chroma-tographic techniques, and form defect-free amorphous films via spin-dip coating. For example TPD is known for its good hole injection/transport properties in OLED applications but suffers from a low Tg (65°C). TPD-OVS hybrid material has a Tg of 142°C while maintaining similar injection/transport properties to TPD. Photoluminescence analysis of the hybrid thin film reveals: 1) a 30 nm blue shift versus their dilute solution counterparts; and 2) 5 hour annealing cycles to within 10°C of their Tg show no indication of eximer formation (no red shift) that often causes reduced efficiencies in polymer LEDs.

The conductivity and magnetotransport properties of compression molded half-metallic CrO2/Polyimide composites over a range of different metallic concentrations have been studied. The conductivity measurements on these composites show negative slope of resistance versus temperature. The magnetoresistance measurement indicates obvious enhancement at low temperatures. The maximum in magnetoresistance (MR) is found to be temperature and metal volume fraction dependent. Significant differences in high and low temperature magnetoresistive behavior in the composite have been observed. The high field, 15 T MR measurements show 23% and 19% MR enhancement at 5K and 75 K, respectively. Thus, it is found that the polymer barrier can contribute to enhancing magnetoresistive properties of the composite.

Building upon earlier success in forming materials with crystalline ordering of POSS via the telechelic architecture with POSS end-capping polyethylene glycols, here we report similar ordering in PEG-POSS thermoplastic polyurethane applicable to a novel hybrid hydrogel. Thus, a unique series of hybrid thermoplastic polyurethanes (TPUs) were synthesized using poly(ethylene glycol) (PEG) as soft segment and incorporating an isobutyl-functionalized POSS diol (TMP POSS diol) in the hard segment. The molecular weight of PEG was systematically varied to include 10, 20, and 35 kDa while the mole ratio of PEG to POSS diol (as chain extender) was chosen as 8:1. The diisocyanate employed for TPU polymerization was 4, 4'-methylenebis(phenyl-isocyanate) (MDI). Wide-angle X-ray diffraction (WAXD) studies revealed that both the hydrophilic soft segments (PEG) and hydrophobic hard segments (POSS) can form crystalline structures driven by micro-phase separation, itself due to thermodynamic incompatibility. Differential scanning calorimetry (DSC) and rheological studies revealed that thermal history is important in controlling the crystallization of a POSS-rich nanophase. Increasing the cooling rate monotonically decreases the crystallinity of POSS-rich phase and results in a decrease in the ultimate dynamic storage modulus following POSS crystallization and an increase of the loss angle for temperatures above Tm of PEG and below Tm of POSS. We conclude that both composition and thermal history are key factors in determing the internal network built by the POSS nanophase, which will have a significant influence on the properties of the resulting hybrid hydrogels now being studied.

Self-extinguishing PMMA/Clay nanocomposites with conventional flame retardant agents, decabromodiphenyl oxide (DB) and antimony trioxide (AO) have been prepared by melt blending using Brabender. The combustion behavior was first investigated by subjecting slabs of the polymer to UL-94 V0 testing. We found that the polymers with only the retardant agents or the clay could not pass. On the other hand all polymers with both components were self-extinguishing. DMA results show that the introduction of 5 wt% clay improves PMMA bending modulus by 28 % and increases Tg by 8 °C. the addition of clay can effectively avoid dripping during burning test. Based on the cone calorimeter data, the general mechanism is proposed that the synergy between the char formation promoted by the clay in condense phase and free radical capture in gas phase due to the DB and AO makes the material become self-extinguishing.

The integration of electro-ionically active inorganic species in polymer matrices allows for the design of either electrode or electrolyte materials depending on the conducting or insulating properties of the polymer used. Conducting polymers can be used as the basis for a variety of hybrid electrode systems, whereas other polymers such as polybenzimidazoles have been used as electrolyte membranes by themselves or in combination with inorganic solid acids. We will discuss the general approach of hybrid design with this in mind and specifically we will describe our recent results on the use of polyoxometalate-containing hybrids in energy storage and conversion devices. In this respect we have worked in our laboratory on electrochemical supercapacitors and fuel cells but emphasis should be made on the broader potential fields of application of this type of materials.

Molybdenum dioxide and vanadium-doped molybdenum dioxide microcrystals were synthesized by a totally new method involving a redox-active monomer route. The two related dioxides had virtually identical crystal structures and the three precursors used in the process could be subsequently divided in two subgroups of two members each, based on their strong similarities in composition and crystal structure, respectively. Molybdenum trioxide (orthorhombic and hexagonal forms) and the vanadium-doped (10%, molar) molybdenum trioxide (hexagonal form) were used in the redox process with excess pyrrole, and at relatively high temperature (325°C) and long reaction time (12 days), formed a heterogeneous new type of organic-inorganic microcomposite. The new material could be described as a molybdenum dioxide crystal in a polymer box, with the size of the crystallite grain depending on the dimensions of the initial molybdenum trioxide grain and the ratio between the unit cell volumes of the initial and final oxide. The procedure took advantage of the relatively high reduction potentials of the Mo6+ and V5+ oxide surface centers towards the oxidative polymerization of pyrrole at intermediate temperatures, and the high catalytic activity of the metal cations in the molybdenum trioxide-based materials towards the total oxidation of the carbon atoms in the organic moiety, at elevated temperatures. This new synthetic route offers good perspectives as precursor composites for nanocrystal engineering in practical applications like heterogeneous catalysis, chemical sensing, nanostructured metallic catalysts, etc.

Planar waveguides with low losses in the infrared (from 0.6–1.1 dB/cm) were prepared with sol-gel derived poly(oxyethylene)/siloxane hybrid doped with zirconium(IV) n-propoxide (ZPO) and methacryloxypropyltrimethoxysilane (MAPTMS). The doped nanohybrids were characterized by small angle X-ray scattering, 29Si nuclear magnetic resonance and photoluminescence spectroscopy and compared with the undoped hybrid material. The results indicate an effective interaction between the zirconium particles and the siliceous nanodomains.

To achieve a simplified microstructure patterning process, patterning in thin films with a singlestep exposure to UV-light or E-beam process for fabrication of integrated optical waveguides and components is of great interest in optics, because the complicated structure developing stage by wet chemical or plasma etching is not required. In this paper, we describe our study on the microstructure patterning in TiO2-doped hybrid glassy polymer thin films by irradiating with focused E-beam. An anhydrous sol-gel process based on hydrolysis and condensation of metal alkoxides with boric acid under non-hydrous conditions was applied to homogeneously incorporating TiO2 into silica network, and transparent glassy TiO2-doped thin films with varied TiO2 concentrations (up to 40 mol%) were prepared by spin coating the hybrid polymer onto fused silica substrates and silicon wafers. The TiO2-doped hybrid material showed a low OH absorption, low optical losses at the telecommunication windows (<0.40 dB/cm at 1550 nm and <0.20 dB/cm at 1310 nm respectively), good thermo-optical linearity and good thermal stability up to 200 °C. Single-step direct surface patterning in the TiO2-doped hybrid glassy films with focused electron beams irradiation showed that fine structure with resolution at submicron level can be fabricated. As the process does not need a developing (etching) process, the profiles of the lines fabricated by the E-beam direct writing showed few distortion. The high precise patterning microstructure with submicron feature sizes in the TiO2-doped hybrid glassy thin films may provide potentials for applications to the fabrication of optical gratings.

The atomic force microscopic technique is utilized to study the spatial distribution of silica nanoparticles embedded in poly(tetraethylene glycol diacrylate) matrix. The cast samples of these hybrid materials show distinct mechanical property change as the weight ratio (SiO2/polyacrylate) reaches 40%. The morphological observation from spin-coated films on silicon substrates shows pronounced nanoparticle network formation correlated to the elasticity transition. The percolating particles reduce the local strain field, i.e. inhibit the deformation of the stratum, and cause the dramatic increase in the Young's modulus. Our experimental result is consistent with recent theoretical prediction [1].

Imide-oligosiloxanes hybrid nanocomposites (Imide HYBRIMER) were synthesized and their unique structure and thermal and mechanical properties were investigated. Imide HYBRIMER was made by reaction with nano-sized amine oligosiloxane (AO) and dianhydride, where oligosiloxane moieties were cross-linked by imide bonds to form three-dimensional nanocomposite. The AO were prepared from condensation reaction with aminopropyltirmethoxysilane (APTS) and diphenylsilanediol (DPSD) under base catalysts without water and solvents. The preparation of imide HYBRIMER was completed through the thermal imidization of amic acids, which were formed by reaction with amines groups in the AO and two different kinds of dianhydrides. The imide HYBRIMER were stable up to 400°C and thermal expansion coefficients measured by thermo-mechanical analysis (TMA) were varied from 33 to 80 ppm/°C. Higher thermal stabilities and mechanical strengths could be obtained by incorporating siloxane moieties in hybrid nanocomposites. The imide HYBRIMER, which has three dimensional network, could induce very low birefringence about 0.003, which was lower than that of linear typed polyimides.