Sol-Gel Science and Technology

The sol-gel method is known to produce materials from solutions either in bulk, coating films, fibers or powders. It is also known that this method makes low temperature processing of materials possible. This technology has dramatically grown in these two or three decades. Sol-Gel Science and Technology covers optical, electronic and magnetic, chemical, mechanical, biomedical and biotechnological materials. Concerning the microstructures, the sol-gel method applies to porous materials, dense materials like glasses and ceramics, organic-inorganic hybrids and nanocomposites. The four volumes of this reference treat four areas that are timely, important and seeing great research activity: -Sol-gel prepared ferroelectrics and related materials. -Sol-gel processing of titanium oxides: photocatalyst and other applications. -Sol-gel prepared organic-inorganic hybrids and nanocomposites. -Sol-gel processing of porous materials: application to catalysts, enzymes, chemical analysis, sensors, and membranes. The goal of these four volumes is to disseminate the recent research results published in recent issues of Journal of Sol-Gel Science and Technology, which is a unique journal devoted to Sol-Gel. Papers have been selected from those published in volumes 16-25 of the Journal of Sol-Gel Science and Technology spanning the years 1999-2002. Volume 1 presents papers on preparation, structure, properties and applications of ferroelectrics and related materials, such as, piezoelectric and pyroelectric materials. Representative ferroelectric materials include BaTiO3, Pb(Ti,Zr)O3, PbTiO3, LiNbO3, KNbO3, LiTaO3, and Pb(ZnNb)O3. Generally, these materials have a high dielectric constant and are characterized by large piezoelectric, pyroelectric and electrooptic effects as well as nonlinear optical effects. On the basis of these unique properties, ferroelectric materials have been applied to produce active elements of various devices. Volume 2 contains papers on sol-gel processing of titanium oxides for photocatalyst and other recent applications. Titanium dioxide, TiO2, is both an old and new material with a variety of interesting functions. Conventionally, TiO2 was used mainly as light-scattering particles in porcelain enamel, ceramic glaze, white points and the suspension-type eraser. A more recent application of similar nature is the incorporation of TiO2 into UV- shielding cosmetics, which protect human skin from UV damage. TiO2 is also employed as nucleating agent for crystallization of glass, providing glass-ceramics. Papers on sol-gel prepared organic-inorganic hybrids and nanocomposites are compiled in Volume 3. Typical organic-inorganic hybrids have a microstructure in which inorganic species like -Si-O-Ti-O- are combined with organic polymers like polymethylmethacrylate chains at the molecular level. Volume 4 compiles papers on the gel as porous material. Porous gels with nano-size pores and micron-size pores are applied to formation of catalysts, enzymes, chemical analysis, sensors and membranes. Pore surfaces are significant because they serve as the absorption and reaction site for catalysts, enzymes, chemical reaction, and sensing molecules or atoms.