The development of new materials always leads to advances in technology and creates innovative solutions to old problems. Nanomaterials and nanotechnologies are the current key elds with great challenges and possibilities. Nanomaterials, also called nanostructured materials, are single phase or multiphase materials with size less than 100 nm at least in one of the dimensions. For example, ultrathin coatings have one nanoscale dimension, nanotubes and nanowires have nanoscale in two dimensions, whereas nanoparticles (NP) are nanoscale in all three dimensions. A nanometer is one billionth of a meter or one thousandth of a micron and is equivalent to chopping a 1 cm length thread into ten pieces and then chopping one of the pieces into a million pieces, as schematically illustrated in Figure 5.1. The magnication required to visualize NPs would be equivalent to enlarging an apple to the size of the Earth. A comparison of nanobers with human hair is shown in Figure 5.2.