What Are Nanomaterials?

Nanometer (nm) is a unit of length like meters and micrometers. One nanometre can be expressed in scientific notation as 1×10−9 m, which is similar to the size of chemical bonds. Nanotechnology is a science and technology that studies the law of motion and interaction of a system composed of substances with a size between 1 and 100 nanometers, as well as possible technical problems in practical applications. Disciplines derived from these studies include: nanoelectronics, mechanics, biology, materials science and processing. Nanomaterials refer to materials with at least one dimension in the nanoscale (1-100nm) in three-dimensional space. It is a new generation of materials composed of nanoparticles with sizes between atoms, molecules and macroscopic systems. Different from the usual bulk macro material system, nanomaterials have a variety of special properties. Nanomaterials enable people to understand nature to a new level. It is a new field between atoms, molecules and macroscopic systems, which has never explored in the past. The study of nanomaterials will bring to people a deeper understanding of the transition from micro to macro. Characteristics of nanomaterials When the particle size is reduced to the nanometer level, it will cause new characteristics of sound, light, electricity, magnetism, and heat. For example: the widely studied II-VI group semiconductor cadmium sulfide, the position of the absorption band boundary and the peak position of the emission spectrum will be significantly blue-shifted as the grain size decreases. According to this principle, cadmium sulfide with different energy gaps can be obtained by controlling the grain size, which will greatly enrich the research content of materials and hope to obtain new uses. Both micron and nano-sized cadmium sulfide are composed of sulfur and cadmium, but by controlling the preparation conditions, materials with different band gaps and luminescent properties can be obtained. In other words, new materials have been obtained through nanotechnology. Nanoparticles often have a large specific surface area. The specific surface area per gram of this solid can reach hundreds or even thousands of square meters, which makes them useful as highly active adsorbents and catalysts in hydrogen storage, organic synthesis and environmental protection. For nanoceramics, nanocrystallization is expected to solve the brittleness problem of ceramics and may exhibit similar plasticity to materials such as metals. Application prospects of nanomaterials The application prospects of nanomaterials are very broad, such as: nanoelectronic devices, medicine and health, aerospace, aviation and space exploration, environment, resources and energy, biotechnology, etc. We know that gene DNA has a double helix structure, the diameter of this double helix structure is about tens of nanometers. Using synthetic light-emitting semiconductor grains with a grain size of only a few nanometers, selectively adsorbing or acting on different base pairs, can "illuminate" the structure of DNA. In short, these nanocrystals are labeled with DNA molecules. Although scientists have been studying the application of nanomaterials, many technologies are still difficult to directly benefit mankind. Below are a few examples of the application of nanomaterials: Titanium dioxide nanotubes. A variety of layered materials can form tubular materials, and the most familiar one is carbon nanotubes. Titanium dioxide nanotube is an open, hollow tube with a specific surface area of 400m2/g, which may have broad application prospects in adsorbents and photocatalysts. Intracrystalline nanocomposite ceramics. Large lighter-colored crystal grains have some dark particles inside. When the ceramic is damaged by external force, the dark particles in these crystals are like nails to inhibit the spread of cracks and play the role of strengthening and toughening ceramic materials. Titanium dioxide nanoparticles. Titanium dioxide is only about 7 nanometers. Thus, such small nanoparticles cannot be seen with the naked eye and only can be seen with the help of an electron microscope. The application of TiO2 nanoparticles as photocatalyst is extensively used for the removal of micropollutants in water treatment and as an alternate to the traditional disinfection techniques.