Nanomaterials are short for nano-scale structural materials. In a narrow sense, they refer to solid materials composed of nanoparticles, where the size of the nanoparticles does not exceed 100nm. In a broad sense, they refer to various solid ultrafine materials whose microstructures are limited by the nanoscale (1-100nm) in at least one dimension. Before 1994, nanostructured materials only included nanoparticles and the nanoblocks and nanofilms they formed. Now, the meaning of nanostructured materials also includes nanoassembly systems, which include not only the components of the nanoparticle entities, but also the matrix with nanoscale space that supports them. In other words, nanomaterials include: nanoparticles, nanoblocks, nanofilms and nanoassembly systems. 1 nanometer = 10-9 meters. Nano is a unit of length. The length of 1nm is about the length of 4 to 5 atoms arranged together, or 1nm is equivalent to one hundred thousandth of the diameter of a hair.