Aerogels were invented by S. Kistler some 80 years ago, but surprisingly, commercialization lags behind by an unusually long time lapse. This should not have been the case. Browsing through this volume it can be argued that the structure-property relationships of aerogels are well-understood. A large array of aerogels have been synthesized and characterized; "exotic" aerogels based on oxides of aluminum, tin, copper, ferromagnetic metals (iron and nickel), all refractories, all rare earths and selected actinides, organic-inorganic aerogel composites, carbide aerogels, selected pure metallic aerogels and several organic aerogels have been described and can be prepared with passable effort. Why then do not we see aerogels all over, around us, from homes to appliances to transportation?Historically and for economic reasons, most fundamental and applied research has focused on silica aerogels. But, the starting materials (mostly alkoxides) are expensive, the process (supercritical fluid drying) is also expensive and potentially hazardous and the endproduct, the silica aerogel, is environmentally unstable (hydrophilic) and mechanically weak (fragile). Tremendous progress has been made along understanding and controlling those issues. The old technology of using water-glass as the starting material for silica aerogels has been revisited; currently, alkoxides are readily replaced by sodium silicate. Hydrophobic aerogels have simultaneously circumvented both the environmental instability problems and the need for supercritical fluid drying via the so-called spring-back effect. Also, mechanically super-strong polymer cross-linked aerogels have been developed. Does not this mean that all of the main barriers to commercialization have been lifted? In principle, the answer to this question is yes. After all, large-scale production of aerogels in conventional shapes such as monolithic panels, as well as in more innovative application-specific forms, such as aerogel pellets and blankets has become possible. Many products are currently evolving, finding their ways into well-selected niche-markets. Traditional kinds of applications use aerogels as thermal and acoustic insulation.

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Hybrid organic-inorganic ionic conductors, also called ormolytes, were obtained by dissolution of LiClO 4 into silica/poly(ethylene glycol) matrices. Solid-state nuclear magnetic resonance (NMR) was used to probe the inorganic phase structure ( 29 Si) and the effects of the temperature and composition on the dynamic behavior of the ionic species ( 7 Li) and the polymer chains ( 1 H and 13 C). The NMR results between -100 and +90 °C show a strong correlation with ionic conductivity and differential scanning calorimetry experiments. The results also demonstrate that the cation mobility is assisted by segmental motion of the polymer, which is in agreement with the results previously reported for pure poly(ethylene oxide), PEO, electrolytes.