scale energy production has yet to be realized. Solar energy technology seems a good bet for the future, but advances in the synthesis of photovoltaic materials will have to precede further development.
Like solar energy, nuclear fusion looks promising in the long run. In this future technology for central power generation, the materials problems are severe and somewhat less well defined than in the photovoltaic area. Some of the problems of conventional nuclear energy will be encountered here, but the most challenging research is likely to be focused on the development of structural materials that will survive the extremely harsh conditions expected in the fusion reactor. For the most part, such materials do not exist today, and future success in this area will be determined by the ability of scientists to come up with innovative solutions.
The advanced materials needed for defense and for aerospace have very special purposes. They often do not have the commercial applications that would justify support for their development in the private sector. Thus government agencies must take the lead in supporting synthesis of novel materials for military applications. Outstanding needs include systems having unique optical and electronic properties as well as systems having unusual strength and toughness.
The materials needed for defense and aerospace span such a wide range that only a few possibilities for materials synthesis in this area can be described here. One such possibility is the development of multitechnology chips that combine infrared detectors with electronic and optical processors. The technical issues here include problems of synthesizing each of the component materials in the presence of the others without destroying the function of any of them.
The Department of Defense has unique needs for new materials in developing its “low observables” or “stealth” technology. The synthesis of such materials requires improved understanding of the physics of detection and of the properties of materials that will be needed to defy detection. The interplay between synthesis, processing, and physics in this area must be strong, especially if the resulting materials are to maintain structural properties with minimal increase in mass and volume.
The Department of Defense also needs unusual materials for sensing and surveillance. Applications range from tracking submarines to detecting toxic chemicals. For example, it would be very useful to find a material superior to polyvinylidenefluoride as an element in acoustic detectors. Electronic ceramics, redox polymers, biomaterials, and membranes are all likely to play roles in advanced chemical sensing systems.
These few examples illustrate the diversity of defense- and aerospace-