Materials whose dielectric constant varies spatially with submicrometer periodicity exhibit diffractive optical properties which are potentially valuable in a number of existing and emerging applications. Here, such systems are fabricated by exploiting the spontaneous crystallization of monodisperse silica spheres into close-packed arrays. By reliance on a vertical deposition technique to pack the spherical colloids into close-packed silica−air arrays, high quality samples can be prepared with thicknesses up to 50 μm. These samples are planar and thus suitable for optical characterization. Scanning electron microscopy (SEM) of these materials illustrates the close-packed ordering of the spherical colloids in planes parallel to the substrate; cross-sectional SEM micrographs of the arrays as well as optical methods are used to measure sample thickness and uniformity. Normal-incidence transmission spectra in the visible and near-infrared regions show distinct peaks due to diffraction from the colloidal layer...

Single-Crystal Colloidal Multilayers of Controlled Thickness

Organic/inorganic hybrid materials prepared by the sol−gel approach have rapidly become a fascinating new field of research in materials science. The explosion of activity in this area in the past decade has made tremendous progress in both the fundamental understanding of the sol−gel process and the development and applications of new organic/inorganic hybrid materials. In this review, a brief summary of the research activities in the field of organic/inorganic nanocomposite materials and a general background of the sol−gel chemistry are first given. The emphasis of this report, however, is placed on the synthesis, structure−property response, and potential applications of the organic/inorganic hybrid networks that possess chemical bonding between the organic and inorganic phases, particularly those systems that were developed in our laboratory since 1985.

Organic/Inorganic Hybrid Network Materials by the Sol−Gel Approach

https://ir.nctu.edu.tw:443/bitstream/11536/30755/1/000083929000013.pdf

Synthesis and characterization of novel segmented polyurethane/clay nanocomposites

Homogeneously dispersed organic–inorganic hybrid nanocomposites can be obtained by increasing the interfacial interactions between both components via the formation of hydrogen bonds or covalent bonds, by mixing various polymers or via the adequate choice of the inorganic precursors The mechanical response of these advanced functional materials is an issue of paramount importance when industrial applications are targeted Large progress in the understanding of the mechanical properties of O–I hybrids has been gained by testing these materials under different conditions (static and dynamic, low and large deformations up to fracture) and using specific techniques developed for the mechanical characterization of conventional materials such as polymers, glasses or ceramics However, the mechanical properties of hybrid O–I materials are dependent on their micro- and nanostructures and on the nature and extent of the O–I interfaces Consequently, predictable mechanical properties for hybrids still represent a major challenge for hybrid materials science Industrial attraction for hybrid materials has been emphasized by the development of new functional coatings An important issue is the interface between the film and the substrate since strong adhesion can be tailored and ensures that delamination of the film will be limited

Mechanical properties of hybrid organic–inorganic materials

A diverse and entirely new class of monomer and polymer technology based on polyhedral oligomeric silsesquioxane (POSS) reagents has been developed. POSS reagents are unique in that they are physically large (approx. 15 A diameter and 1000 amu) and are composed of a robust silicon–oxygen framework that can be easily functionalized with a variety of organic substituents. Appropriate functionalization of POSS cages allows for their incorporation into traditional thermoplastic resins without modification of existing manufacturing processes. The incorporation of POSS segments into linear copolymer systems results in increased glass transition and decomposition temperatures, increased oxygen permeability and reduced flammability and heat evolution, as well as modified mechanical properties relative to conventional organic systems. © 1998 John Wiley & Sons, Ltd.

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Polyhedral oligomeric silsesquioxane(POSS)‐based polymers

Some General Trends in the Area of Organic-Inorganic Composites Organic-Inorganic Hybrids with a Crystalline Polymer Matrix Inorganic-Protein Interactions in the Synthesis of a Ferrimagnetic Nancomposite Ion-Exchange Intercalation into the MPS[3 Layered Compounds: Design of Nanocomposites with Unusual Magnetic Electrical, and Nonlinear Optical Properties Preparation and Characterization of Nanocomposites of Poly(ethylene oxide) with Layered Solids Polymer-Clay Hybrids (Perfluorosulfonate Ionomer)-(Inorganic Oxide) Nanocomposites: Organic Modification of Surfaces of Silicon Oxide Nanoparticles Grown In Situ Nanostructured Organic-Inorganic Hybrid Materials Synthesized Through Simultaneous Processes Multiple Size Scale Structures in Silica-Siloxane Composites Studied by Small-Angle Scattering Composite Polymer Colloid Nucleated by Functionalized Silica Vinyl-Polymer-Modified Hybrid Materials and Photoacid-Catalyzed Sol-Gel Reactions Hybrid Organic-Inorganic Interpenetrating Networks A New Route to Polymer-Filled Glass: Hybrid Interpenetrating Networks with Appreciable Toughness Solidification of Colloidal Crystals of Silica Thermo-irreversible Gelation and Percolation-Based Mechanical Response via Metal-Olefin Coordination in Diene Polymers Hybrid Organic-Inorganic Silica Materials: Chemical Evidence for Organization in the Solid Hybrid Organic-Inorganic Materials: The Sol-Gel Approach Sol-Gel-Derived Silica-Siloxane Composite Materials: Effect of Reaction Conditions in Polymer-Rich Systems Hypervalent Spiro Polysiliconate and Polygermylate Ionomers: Novel Ladder and Network Materials Hexylene- and Phenylene-Bridged Polysiloxane Network Materials Structural Design of High-Performance Polymers for Sol-Gel Processing Preparation and Properties of High-Clarity Polyamide-Silica Hybrid Materials Preparation and Mechanical Properties of Polybenzoxazole-Silica Hybrid Materials Morphological Studies of Conductive Polyemers Deposited onto High-T[c Superconductors Novel Organic-Inorganic Composite Materials for Photonics Inorganic-Organic Hybrid Coatings for Metals and Glass Surfaces Surface Modification of Carbon Fibers for Advanced Composite Materials

Hybrid Organic-Inorganic Composites

Molecular composites were prepared from sulfonated modifications of polysulfone and polyphenylsulfone by incorporating relatively stiff polybenzimidazole (PBI) chains into them. The composites were characterized by Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), thermal mechanical analysis (TMA), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The FT-IR results demonstrated strong specific interactions between the sulfonated polymers and the PBI, which was presumed to be the reason for the enhanced miscibility observed. Miscibility was also indicated in the DSC and TMA results, by the presence of a single glass transition temperature (which was composition dependent), although there did appear to be a small degree of phase separation. TGA results showed improvements in the thermal stability of the polymer matrix because of the incorporation of PBI. Results from SEM were also consistent with considerable miscibility. Microcellular foams processed from these molecular composites had partial open-cell cell structures, with average cell sizes ranging from 0.2 to 5 μm, in unusual bimodal cell-size distributions.

Molecular composites by incorporation of a rod-like polymer into a functionalized high-performance polymer, and their conversion into microcellular foams

C. Y-C. Lee

Papers

Hybrid Organic-Inorganic Composites

Molecular composites by incorporation of a rod-like polymer into a functionalized high-performance polymer, and their conversion into microcellular foams