Nanomaterials have the structural features in between of those of atoms or molecules and the bulk materials. The properties of nanomaterials change as their size approaches the nanoscale.

Thermal properties : Nanomaterials have lower melting temperatures, when the particle size decreases below 100 nm. It is due to the fact that the surface energy level increases as size decreases. Also due to a huge fraction of surface atoms in the total amount of atoms.

Example: The melting point of gold particles lower to about 300°C for particles with diameters of less than 5 nm, which is much lower than the normal melting point of 1063°C for gold.

Electrical properties : Nanomaterials can hold considerably more energy than conventional ones because of their large grain boundary area. They are materials in which an optical absorption band can be introduced, or an existing band can be altered by the passage of current through these materials, or by the application of an electric field.

Examples: Nickel-metal hydride batteries made of nanocrystalline nickel can hold considerably more energy than conventional ones and require far less frequent recharging and to last much longer.

Examples: Nickel-metal hydride batteries made of nanocrystalline nickel can hold considerably more energy than conventional ones and require far less frequent recharging and to last much longer.

For example, the nearly spherical, defect-free silicon nanospheres with diameters from 20 to 50 nm possess hardness of up to 50GPa or four times greater than that of the bulk silicon.

Magnetic properties : Ferromagnetism of a substance refers to its high susceptibility to magnetization. Ferromagnetic particles get unstable when particle size reduces below a certain value. In nanomaterials a large number of atoms will be present at the surface. These atoms will have less-co-ordination number and hence posses local magnetic moment with in themselves. Surface energy provides sufficient energy for domains to spontaneously change. As a result, ferromagnetic materials become paramagnetic.

Also, non-ferromagnetic bulk materials exhibit ferromagnetic-like behavior when prepared in nano range.

Example: Bulk gold and Pt are non-magnetic, but at the nano size they are magnetic. Magnets made of nanocrystalline yttrium-samarium-cobalt grains possess very unusual magnetic properties and are used in submarines, land-based power generators, and medical diagnostics.