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What is nanotecnology?

The contribution of this section has been done by F. Antolini (ENEA)

What is nanotechnology?

It is not easy to give a definition of Nanotechnology. In 2006, Nature nanomaterials (Nature nanotechnology 1, 8-10, 2006) asked to different researchers the meaning of this term receiving different answers. There are three main concepts that can define the nanotechnology:

i) the size limitation of materials and devices included between 1-100 nm;

ii) the nanostructure has to be man made;

iii) the nanostructure has special properties due exclusively to its size.

Taking into account these criteria a good definition of Nanotechnology is the design, characterization, production, and application of structures, devices, and systems by controlled manipulation of size and shape at the nanometer scale (atomic, molecular, and macromolecular scale) that produces structures, devices, and systems with at least one novel/superior characteristic or property (;

As consequence of this definition Nanomaterials are the materials that have at least one dimension less than 100 nm, synthesised by man, having new or superior properties with respect to the corresponding bulk material.

Recently also the European Commission gave a definition of nanomaterial. Here is added the idea that also the amount of the material is important to define a material as nanomaterial. The contribution of human is also less important and a particular interest is given to the safety.

"2 ‘Nanomaterial’ means a natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50 % or more of the particles in the number size distribution, one or more external dimensions is in the size range 1 nm-100 nm.

In specific cases and where warranted by concerns for the environment, health, safety or competitiveness the number size distribution threshold of 50 % may be replaced by a threshold between 1 and 50 %.

3. By derogation from point 2, fullerenes, graphene flakes and single wall carbon nanotubes with one or more external dimensions below 1 nm should be considered as nanomaterials."


What does it means "nano"?

Probably the following picture explains better than words the meanning of nanomaterials and nanotechnology.





















What makes the nanomaterials so different and intriguing?

The interest of nanotechnology stems from the properties that these materials display with respect to their bulk counterparts. From the chemical point of view the nano-materials have the same composition of the corresponding bulk materials, but due to their reduced size and high surface to volume ratio they give rise to different properties with respect to the bulk counterpart.

Reduced size: the fundamental electronic, magnetic, optical, chemical properties are modified by decreased size of the materials (quantum size effect). These changes modulate the macroscopic properties of the final material.

High surface to volume ratio: In nanomaterials, the small feature size ensures that many atoms, perhaps half or more in some cases, will be near interfaces. Surface properties such as energy levels, electronic structure, and reactivity can be quite different from interior states, and give rise to quite different material properties.


Nanotechnology is a multidisciplinary research area

The Nanotechnology is a multidisciplinary research area: Physics, Materials science, Chemistry and Biology are its scientific basis. Ideally from Physics stems nanotechnology for functional devices, from Materials science and Chemistry stems nanotechnology for new bulk, composites and coatings materials, from Biology stems nanobiotechnology for new markers for diagnostic, drug delivery etc.



Nanomaterials: a brief history

Nanotechnologies were already used in the manufacturing of objects since ancient times. A remarkable example of this is the Licurgus Cup exposed at London British Museum.

The Licurgus Cup (IV century d.C British Museum London) is “green” when observed in reflection, is “red” when illuminated in transmission. This effect is due to the gold and silver nanoclusters inside the glass.

Another important example is its application in pottery decoration.   The Mastro Giorgio pottery (1528, Ceramic Museum of Gubbio)  is a good example showing how the red and yellow colours, due to the presence of silver and copper nanoclusters, were used.

Nanomaterials Classification


All conventional materials like metals, semiconductors, glass, ceramic or polymers can in principle be obtained with a nano-scale dimension. The classification of nanomaterials can follow different criteria like the size, the phase composition and the way of manufacturing.


Nanomaterials classification: the size

Following the “dimension” criterion here are reported some examples of 3, 2 and 1 dimension materials.

3 dimension (3D) materials: quantum dots or nanoparticles and Fullerene.

Nanoparticles are formed by tens or hundreds of atoms and can have different size and shape.

Fullerene is formed by carbon atoms forming a “ball” of nanometer diameter.

2  (2D) dimension materials: Carbon nanotubes

Carbon nanotubes are linear structures that can reach microns of length with nanometric diameter. They can be single or multiwall.

1 dimension (1D) materials: Graphene and inorganic layer

Graphene is formed by a layer of a carbon atoms, while other inorganic layers can be grown to modify the surfaces of bulk materials

Nanolayers are a very important class of nanomaterials. Often they are used to modify the surface of bulk materials.


Nanomaterials classification: the phase composition

In the nanocomposites (phase composition  criterion) materials a nanomaterial (nanoparticles, nanotubes, layers) acts as a filler of a matrix material that in most cases is a polymer.

The nanomaterial contribute to the nanocomposites new or improved properties (mechanical, electrical, optical etc.).

In the nanocomposites the material matrix can be different from a polymer. Another common matrix is the ceramic or the glass (inorganic nano-composites): the glass is mixed with nanoparticles to obtain different colors.


Applications of the Nanomaterials and Nanotechnology

The are several applications of the nanomaterials in different fields. Below are listed the most important areas where nanotechnology affects. In all these fields there is a strong effort to bring to the market the research on nanotechnologies and nanomaterials.

Medicine: diagnostics, drug delivery, synthetic bones.

Energy: energy production, energy saving, fuel cells.

Information and Communication Technology: optoelectronic devices, TV, displays, memory storages.

Heavy industry: construction (nanoparticle in glass, coatings etc.), automotive, aerospace, catalysis.

Consumer goods: food packaging, food detection of contaminants, sporting goods, textiles, cosmetics.

Nanomaterials real products

Nanotechnology already is part of our life. There are a lot of products on the market made by using nanotechnology. Below is reported some record of the impact of nanotechnology and nanomaterials on real products (source “The Project on Emerging Nanotechnologies”