Nanoparticles and its applications

Those objects that have at least one dimension which is not more than 100 nm, is called as nanoparticles and study of nanoparticles is called as nanotechnology. These particles exhibit some special properties which are mainly due to their small size that is enough to accommodate their electrons and to produce the quantum effects. Because the properties of materials change as their size approaches to nano-scale and as the percentage of atoms at the surface of a material becomes significant. The high surface area to volume ratio of nanoparticles provides a tremendous driving force for their diffusion, especially at the elevated temperatures. Suspensions of nanoparticles are possible because of the interaction of the particle surface with the solvent is strong that is enough to overcome the density differences, which otherwise usually result in a material either sinking or floating in a liquid. Moreover, the nanoparticles have been found to impart some extra properties to various day to day products. These particles can have the amorphous or crystalline form and their surfaces can act as carriers for liquid droplets or gases. Examples of materials in crystalline nanoparticles form are fullerenes and carbon nanotubes, while the traditional crystalline solid forms are graphite and diamond.

Nanoparticle research is currently an area of intense scientific interest due to a wide variety of potential applications. There are two approaches that are used in the synthesis of nanoparticles are: a) 'top down' and b) 'bottom up'. In top down method, the bulk material (solid phase) is dissociated into small size particle (nanoparticle) by external force and it also sub divide into two more process one is dry grinding and second one is wet grinding. In bottom up method, the nanoparticles are produced by the process of molecular condensation in liquid and gaseous phase. Nowadays, the green synthesis of nanomaterial is very popular because of its eco friendly and profitable nature than the chemical synthesis. Nanoparticle characterization is necessary to create a general understanding regarding the control over the nanoparticle synthesis and to find out their applications. Characterization is done by using a variety of different techniques which are electron microscopy (TEM, SEM), atomic force microscopy (AFM), dynamic light scattering (DLS), x-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF), ultraviolet-visible spectroscopy, dual polarisation interferometry and nuclear magnetic resonance (NMR).

Applications of nanoparticles:

01. Electronics (nanowiring that have a low boiling point)
02. Transportation and telecommunication
03. Imaging
04. Biomedical applications
05. Pollution remediation
06. Cosmetics
07. Coatings
08. Materials (high temperature superconductivity material)
09. Mechanical engineering
10. Nanopaints
11. Chemical Catalysis

Despite these, there is a heightened concern today that the development of nanotechnology will negatively impact public health, and it is indisputable that engineered nanomaterials are a source of nanoparticle pollution when not safely manufactured, handled, and disposed of or recycled. Monitoring of nanoparticle exposure and their control strategies are required. Indeed, there is a need for a new discipline - nanotoxicology - that would evaluate the health threats posed by nanoparticles. Further, the development of laws and policies are required in order for safely managing all aspects of nanomaterial manufacturing, industrial and commercial use, and recycling.

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