From Nanostructures And Nanomaterials: Synthesis, Properties & Applications
8.4 Physical Properties of Nanomaterials
Between the dimensions on an atomic scale and the normal dimensions, which characterize bulk material is a size range where condensed matter exhibits some remarkable specific properties that may be significantly different from the physical properties of bulk materials. Some such peculiar properties are known, but there may be a lot more to be discovered. Some known physical properties of nanomaterials are related to different origins: for example, (i) large fraction of surface atoms, (ii) large surface energy, (iii) spatial confinement, and (iv) reduced imperfections. The following are just a few examples:
Nanomaterials may have a significantly lower melting point or phase transition temperature and appreciably reduced lattice constants, due to a huge fraction of surface atoms in the total amount of atoms.
Mechanical properties of nanomaterials may reach the theoretical strength, which are one or two orders of magnitude higher than that of single crystals in the bulk form. The enhancement in mechanical strength is simply due to the reduced probability of defects.
Optical properties of nanomaterials can be significantly different from bulk crystals. For example, the optical absorption peak of a semiconductor nanoparticle shifts to a short wavelength, due to an increased band gap. The color of metallic nanoparticles may change with their sizes due to surface plasmon resonance.
Electrical conductivity decreases with a reduced dimension due to increased surface scattering. However, electrical conductivity of nanomaterials could also be enhanced appreciably, due to the better ordering in microstructure, e.g. in polymeric fibrils.
Products & Services
Topics of Interest
8.5 Summary Many characterization and analytical techniques have been applied for the study of nanomaterials and nanostructures; only a few widely used methods are reviewed in this chapter. Both...
Nanomaterials are metallic, semiconductor, or isolator materials that have at least a nanosize dimension and, hence, produce quantum confinement of electron motion and render size-dependence of...
Chapter List Nanomaterials Production by Soft Chemistry Hydrothermal Synthesis of Nanomaterials Ehda in Particle Production Application of Electrospray in Nanoparticle Production Dynamic...
Nanotechnology has been discussed a few times in this column in recent years, perhaps not surprisingly because the products of nanotechnology seem to be finding applications in almost every sector of...
1.1 Introduction Nanotechnology deals with small structures or small-sized materials. The typical dimension spans from subnanometer to several hundred nanometers. A nanometer (nm) is one billionth...