ABSTRACT
It is well known that nanomaterials possess different chemical and physical properties than bulk materials of identical composition. When the particle size decreases to nanoscale, the fundamental characteristics of the material often changes, resulting in completely new properties. For instance, previously colorful materials become transparent, insulators become conductive, or the melting point of nanoparticles evidently drops when their size is below 100 nm (Nalwa 2004; Wang 2000). When the particle size decreases, the proportion of atoms found at the surface relative to the atoms in the interior of the particle increases. Thus, nano-objects have a much larger surface area per unit mass compared with bigger particles. The increase in the
1.1 Introduction ......................................................................................................3 1.2 Particle Size/Size Distribution ..........................................................................7 1.3 Aggregation and Agglomeration State ........................................................... 10 1.4 Shape ............................................................................................................... 11 1.5 Surface Area ................................................................................................... 11 1.6 Composition .................................................................................................... 12 1.7 Surface Chemistry .......................................................................................... 13 1.8 Surface Charge ............................................................................................... 15 1.9 Solubility/Dispersibility .................................................................................. 16 1.10 Control of Properties by Surface Functionalization ....................................... 16 Acknowledgments .................................................................................................... 19 References ................................................................................................................ 19
surface-to-volume ratio results in an increase in the particle surface energy, which may render them more reactive.
