Encapsulation inorganic materials

Inorganic Materials. Sol—gel chemistry involves first the formation of a sol, which is a suspension of soHd particles in a Hquid, then of a gel, which is a diphasic material with a soHd encapsulating a solvent. A detailed description of the fundamental chemistry is available in the Hterature (2—4). The chemistry involving the most commonly used precursors, the alkoxides (M(OR) ), can be described in terms of two classes of reactions ... 

Common to all encapsulation methods is the provision for the passage of reagents and products through or past the walls of the compartment. In zeolites and mesoporous materials, this is enabled by their open porous structure. It is not surprising, then, that porous silica has been used as a material for encapsulation processes, which has already been seen in LbL methods [43], Moreover, ship-in-a-bottle approaches have been well documented, whereby the encapsulation of individual molecules, molecular clusters, and small metal particles is achieved within zeolites [67]. There is a wealth of literature on the immobilization of catalysts on silica or other inorganic materials [68-72], but this is beyond the scope of this chapter. However, these methods potentially provide another method to avoid a situation where one catalyst interferes with another, or to allow the use of a catalyst in a system limited by the reaction conditions. For example, the increased stability of a catalyst may allow a reaction to run at a desired higher temperature, or allow for the use of an otherwise insoluble catalyst [73]. 

Sealosafe A family of processes for encapsulating inorganic and organic wastes in a cementitious material suitable for landfill. The product, known as Stablex, is made from a cement and an aluminosilicate and may incorporate pulverized fly ash. Developed by C. Chappell in the United Kingdom in the 1970s and now operated in a number of countries. Offered by the Stablex Corporation, Radnor, PA. The environmental acceptability of the product has since been criticized. 

M. Alvaro, A. Corma, B. Ferrer, M.S. Galletero, H. Garcia, and E. Peris, Increasing the stability of electroluminescent phenylene vinylene polymers by encapsulation in nanoporous inorganic materials, Chem. Mater., 16 2142-2147, 2004. 

Biomimetic Synthesis of Nanoparticles Carbonyl Complexes of the Transition Metals Metallic Materials Deposition Metal-organic Precursors Polynuclear Organometallic Cluster Complexes Porous Inorganic Materials Self-assembled Inorganic Architectures Semiconductor Nanocrystal Quantum Dots Sol-Gel Encapsulation of Metal and Semiconductor Nanocrystals. 

Important research was devoted to find appropriate conditions for an efficient encapsulation/anchoring of azo dyes in/on various inorganic substrates in order to improve their light-fastness qualities and water or oil resisting properties. The most widely used inorganic materials to elaborate such dye composites were clay minerals, e.g. smectites [1] or hydrotalcite [2], but also mesoporous silica based materials [3,4]. 

Entrapment or intercalation of metal species in pores and cavities of solid supports has frequently been used for the immobilization of catalysts in inorganic materials such as zeolites, clays, charcoals, silicas, aluminas, and other solids. Though this review article focuses on the immobilization of palladium complexes on polymer supports via covalent and/or coordination bonds, recent novel approaches to polymer-supported palladium species (including palladium nanoparticles) via nonbonding immobilization, such as encapsulation and incarceration, are intriguing because of their high potential for utility. In this section, several representatives are introduced. 

For many applications, the encapsulation of inorganic material is of high interest either the inorganic components should be protected from the environment (e.g., air-sensitive components) or the environment from potentially toxic components, or polymeric films with improved color, mechanical, or gas diffusion properties, having finely distributed (and protected) inorganic material for coating applications, are desired. Furthermore, UV-blocking applications are reported [81-83],... 

Clemens, W. and K. Landfester, Miniemulsion polymerization as a means to encapsulate organic and inorganic materials. Adv. Polym. Sci. 233 (2010) 185-236. 

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