ABSTRACT
The subject of nanocomposites is especially interesting because at least one of a nanocomposite’s phases has one or more dimensions-length, width, or thickness-in the nanometer range, which is usually defined as 1 to 100 nm. This is the range where phenomena associated with atomic and molecular interactions strongly influence the macroscopic properties of the materials, but this is also the length scale where our knowledge of how to synthesize and process materials is the weakest. Nevertheless, it is very well known that the catalytic, mechanical, electronic, optical, and other properties of a material can significantly and favorably be altered when that material is fashioned from nanoscale building blocks.1-6 For instance, nanocrystalline copper is up to five times harder than conventional copper, and ceramics, which normally are brittle, can be made more easily deformable if their grain size is reduced to low nanometer range. Such improved properties can also be incorporated into nanocomposites, in which the building blocks-say, nanoscale metal or carbon particles, or nanometer-thick filaments or sheets of a ceramic-are dispersed in a matrix of another material, such as a polymer. Because the building blocks of a nanocomposite are nanoscale, they have an enormous surface area, and therefore significantly create large interfaces between the two intermixed phases. The special properties of the nanocomposite arise from the interaction of its phases at these interfaces. The challenge, however, lies in fabricating these materials with the required atomic specifications.
