The Nanoscience Paradigm: “Size Matters!”

The essential feature of nanomaterials is that their physical and chemical properties are size dependent, making it possible to engineer the material properties not only by defining its chemical composition, but also by tailoring the size, shape, and surface chemistry of the nanostructures, and the way in which individual building blocks are assembled. This chapter addresses the origin of the size dependence of the properties of nanomaterials, which can be traced to two fundamental nanoscale effects: (a) the increase in the surface/volume ratio with decreasing size, and (b) spatial confinement effects. Furthermore, the definition and classification of nanomaterials is introduced, and the techniques used to fabricate and study them are briefly addressed, with emphasis on nanoparticles of inorganic materials.