Hybrid materials classification

It is evident that a completely consistent classification of organic-inorganic mesoporous hybrid materials based on silica is hard to deduce. Before we proceed, some (hopefully) clarifying remarks on this issue will be made. 

Table I Proposed classification of hybrid materials, showing the dimensionality of different structures with respect to both organic connectivity between metal centers (O") and extended inorganic connectivity (I") (see text for explanation)...

In this review, nanoporous dielectric materials have been presented. The preparation techniques, methods of pore generation, and materials classification were discussed. Inorganic, organic, and hybrid films were also discussed. The nanoporous dielectric films were classified by preparation method, which includes block copolymer, solvent as porogen approach, surfactant templating, and sol-gel approach. This is still a very active field of research because no one film has satisfied all the stringent requirements in semiconductor device processing. 

A classification of methods for preparing polymer-layered inorganic solid compounds takes into account the main processes involved in the synthesis of the final hybrid material. The nature of both the 2D host solid and the guest polyma- determines the pathway applicable to obtain a particular nanocomposite and, in certain cases, is decisive in the behavior of the resulting material. In... 

Despite an univocal definition of the term hybrid is still missing in the literature, a possible general classification has been reported by Gomez-Romero in the case of bicomponent systems, which represent the most frequently reported materials. Figure 17.6 reports a similar classification scheme, suitably adapted to the nanosized materials that are most commonly reported in electroanalytical applications. Composites constitute a family of hybrid materials that play major... 

Figure 2 Classification of reports on PEG-hybrid materials in medical and technological fields.

In Section 13.2, we introduce the materials used in OLEDs. The most obvious classification of the organic materials used in OLEDs is small molecule versus polymer. This distinction relates more to the processing methods used than to the basic principles of operation of the final device. Small molecule materials are typically coated by thermal evaporation in vacuum, whereas polymers are usually spin-coated from solution. Vacuum evaporation lends itself to easy coaling of successive layers. With solution processing, one must consider the compatibility of each layer with the solvents used for coating subsequent layers. Increasingly, multilayered polymer devices arc being described in the literature and, naturally, hybrid devices with layers of both polymer and small molecule have been made. 

Fig. 15.1 Classification of sp2- and sp3-hybridized nanostructured carbon materials. CNTs are considered as open-end tubes, thus also exposing prismatic edge surfaces.

Although the terms nanocomposite and hybrid are often used to define similar materials, we will use the classification indicated by Vilatelaand Eder [1], Nanocomposites are multiphase materials, in which one phase is dispersed in a second phase, resulting in a combination of the individual properties of the component materials. The volume fraction of the nanocarbon is typically less than a few percent. Nanocarbon hybrids are instead formed by both components with similar volume fractions. The inorganic compound (such as semiconductor nanoparticles) is deposited onto the surface of the... 

In this chapter, supramolecular chemistry related to developments in materials fabrication and functionalization at the mesoscale are discussed, with an emphasis on those systems based on organic-inorganic hybrid structures. The contents of this chapter are classified into (1) supramolecular chemistry within mesoscopic media, (2) supramolecular assembly at the mesoscale, and (3) supramolecular materials at the mesoscale. Despite this classification these topics have considerable similarities. 

Hybrid framework compounds, including both metal-organic coordination polymers and systems that contain extended inorganic connectivity (extended inorganic hybrids), have recently developed into an important new class of solid-state materials. We examine the diversity of this complex class of materials, propose a simple but systematic classification, and explore the chemical and geometrical factors that influence their formation. We also discuss the growing evidence that many hybrid frameworks tend to form under thermodynamic rather than kinetic control when the synthesis is carried out under hydrothermal conditions. Finally, we explore the potential applications of hybrid frameworks in areas such as gas separations and storage,... 

The three general categories of materials are metals, ceramics (inorganic materials), and polymers. This broad classification is based mainly on the nature of the chemical bonds, which are metallic, ionic, and covalent. However, these latter divisions do not have particularly distinct boundaries in most cases, because the chemical bond is often a hybrid of these three types. For example, most covalent bonds have some degree of ionic character... 

This chapter is concerned with the essential classification of the materials used to repair teeth and restore their function. As far as direct restoratives are concerned, we follow the classification on Mount et al. [1] and consider that the two basic types of modem tooth-coloured materials are the composite resins and the glass-ionomer cements. They are fundamentally different, and though hybrids have been attempted, combining their advantages is not feasible for sound scientific reasons. 

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