This book, a collection of 12 original contributions and 4 reviews, provides a selection of the most recent advances in the preparation, characterization, and applications of polymeric nanocomposites comprising nanoparticles. The concept of nanoparticle-reinforced polymers came about three decades ago, following the outstanding discovery of fullerenes and carbon nanotubes. One of the main ideas behind this approach is to improve the matrix mechanical performance. The nanoparticles exhibit higher specific surface area, surface energy, and density compared to microparticles and, hence, lower nanofiller concentrations are needed to attain properties comparable to, or even better than, those obtained by conventional microfiller loadings, which facilitates processing and minimizes the increase in composite weight. The addition of nanoparticles into different polymer matrices opens up an important research area in the field of composite materials. Moreover, many different types of inorganic nanoparticles, such as quantum dots, metal oxides, and ceramic and metallic nanoparticles, have been incorporated into polymers for their application in a wide range of fields, ranging from medicine to photovoltaics, packaging, and structural applications.

Silicon based materials and polymers are made of silicon containing polymers, mainly macromolecular siloxanes (silicones). This book covers the different kinds of siliconbased polymers: silicones, silsesquioxanes (POSS), and silicon-based copolymers. Other silicon containig polymers: polycarbosilanes, polysilazanes, siloxane-organic copolymers, silicon derived high-tech ceramics: silicon carbide and oxycarbide, silicon nitride, etc. have also a very important practical meaning and a hudge number of practical applications. These materials make up products in a variety of industries and products, including technical and medical applicatons. Polycrystalline silicon is the basic material for large scale photovoltaic (PV) applications as solar cells. Technical applications of crystalline (c-Si) and amorphous (a-Si) silicon (fully inorganic materials), silicon nanowires are still quickly growing, especially in the fi eld of microelectronics, optoelectronics, photonics. and photovoltaics, catalysts, and different electronic devices (e.g. sensors, thermoelectric devices). This book is ideal for researchers and as such covers the industrial perspective of using each class of silicon based materials. Discusses silanes, silane coupling agents (SCA), silica, silicates, silane modified fillers, silsesquioxanes, silicones, and other silicon polymers and copolymers for practical applications as polymeric materials and very useful ingredients in materials science.

BACKGROUND Polysiloxanes have chains constructed of alternately arranged silicon and oxygen atoms with organic groups attached to the silicon atoms. This structure gives them a unique combination of properties that hold great interest for a host of practical applications. Although they have been known and manufactured for many years, their applications continue to expand rapidly and this boosts progress in the generation of new and modified polysiloxanes. Polysiloxanes constitute the oldf'"' known class of silicon-based polymers and the broadest one when viewed in terms of the variety of structures differing in topology and the constitution of organic substituents. There are also many and various types of siloxane copolymers, some of purely siloxane structure and others of siloxane-organic composition. There is no doubt that polysiloxanes are the most technologically important silicon-based polymers. The broad class of model materials known as silicones is based on polysiloxanes. They are also the best known, as most research in the area of silicon polymers has for many years been directed towards the synthesis of new polysiloxanes, to understanding their properties and to extending their applications.

Silicon Based Polymers presents highlights in advanced research and technological innovations using macromolecular organosilicon compounds and systems, as presented in the 2007 ISPO congress. Silicon-containing materials and polymers are used all over the world and in a variety of industries, domestic products and high technology applications. Among them, silicones are certainly the most well–known, however there are still new properties discovered and preparative processes developed all the time, therefore adding to their potential. Less known, but in preparation for the future, are other silicon containing-polymers which are now close to maturity and in fact some are already available like polysilsesquioxanes and polysilanes. All these silicon based materials can adopt very different structures like chains, dendrimers, hyperbranched and networks, physical and chemical gels. The result is a vast array of materials with applications in various areas such as optics, electronics, ionic electrolytes, liquid crystals, biomaterials, ceramics and concrete, paints and coatings ... all needed to face the environmental, energetical and technological issues of today. Some industrial aspects of the applications of these materials will also be presented.

This issue of Current Topics in Microbiology and Immunology records the proceedings of a Workshop on the Immunology of Sili cones held at the Natcher Conference Center, National Institutes of Health, Bethesda, Maryland, March 13 and 14, 1995. A large num ber of investigators from North America and Europe met to discuss available data on how the immune system responds to silicones and related materials. Some aspects of this field are controversial. Nonetheless, the meeting was marked by a civil and open ex change of scientific information and divergent interpretations, re flecting the traditions of scientific communication. Each invited participant was asked to submit an article sum marizing his/her presentation. Most of the papers are published as submitted, with only editorial changes to conform with the guide lines given to each contributor or revisions to clarify aspects of the paper. The papers should not be regarded as peer-reviewed publi cations. This preface will attempt to outline some of the immu nological areas of investigation relating to silicones.

This book provides the first unified reference work for silicon-based polymers. It brings together in one volume research on the synthesis, properties, chemistry, electronic structure, applications, and technology of these materials. The volume is built around a series of critical overviews of these rapidly advancing fields and is supplemented by a substantial number of shorter papers that focus on current findings. It also provides insight into possible directions for future scientific and technological advances in the field.