Graphene network, one of the most studied nanomaterials.
When we think of technology, we imagine devices, machines, screens. But did you know that there is a branch of science that operates at scales so small they completely escape the human eye, and that some of the most promising advances of the 21st century are being developed there?
Nanotechnology is precisely responsible for that: manipulating matter at the nanoscale. To put it in perspective, a nanometer (nm) is equivalent to one billionth of a meter, that is, 1 nm = 0.000000001 m (1 × 10⁻⁹ m).
To give you an idea of how small this scale is: a single human hair measures between 60,000 and 100,000 nanometers in width. This means that a nanoparticle can be hundreds or thousands of times smaller than the thickness of a hair.
Size comparison, from everyday objects to atomic and molecular structures. Source: http://www.gaiaciencia.com/2015/02/que-es-la-nanotecnologia/
If we search for a more detailed definition:
“Nanotechnology involves understanding the world of the small to innovate through constructing with atoms and molecules in order to respond to growing socioeconomic needs” - Prof. Dr. Luis Alberto D´Andrea.
And why is it so interesting to observe and manipulate matter at that scale? Because the properties of materials at the nanoscale differ from those at the macro or conventional level. Some of the characteristics that emerge at the nanoscale include:
Quantum effects: the behavior of electrons and other particles does not follow the rules of classical physics, but rather quantum physics comes into play, affecting optical, electronic, and magnetic properties.
Increased specific surface area: by reducing the size of particles, the surface area to volume ratio increases, meaning that the smaller the size, the greater the surface/volume ratio, which can influence reactivity, absorption, or conductivity.
Predominance of different forces: while at large scales the force of gravity dominates, at the nanoscale, electrostatic and van der Waals forces dominate.
Modification of optical properties: when materials are reduced to nanoscale, their way of interacting with light can change. In the case of nanomaterials, this can cause the color we perceive to vary according to the size of the particles. This occurs due to optical phenomena specific to that scale, which are not observed in larger materials.
Image: colloidal gold particles obtained by chemical reduction (Alshammari et al., 2012).
Change in mechanical properties: certain materials may become harder, more elastic, or even more brittle as their size decreases. This will depend on their internal structure and how they conform at the atomic level.
This set of distinct properties opens up a wide range of possibilities. We can think, design, and manufacture materials with tailored characteristics for applications that were previously unthinkable.
When did it arise?
In 1959, Richard Feynman mentioned the possibility of manipulating atoms and molecules in a lecture, but it wasn't until 1974 that Japanese scientist Norio Taniguchi proposed the term 'nanotechnology'.
Decades later, the concept began to gain traction alongside advancements in microscopy and manufacturing techniques. Today, nanotechnology is far from being a future promise: it is a reality that is already applied in multiple industries.
However, the use of nanoscale structures predates the modern concept. A notable example is the Lycurgus Cup, a Roman glass piece from the 4th century that changes color depending on how light hits it, due to the presence of metallic nanoparticles in its composition.
The Lycurgus Cup under frontal light (left) and transmitted light (right). Source: The Trustees of the British Museum / Art Resource, NY. Via Smithsonian Magazine (2013).
It can be observed that the cup exhibits changes in color when exposed to light from different directions, due to the presence of silver and gold nanoparticles.
Where do we find it?
Some areas where nanotechnology is already making its mark:
Nanomedicine: from controlled drug delivery systems to new methods of molecular-level diagnosis.
Electronics: increasingly smaller, more efficient devices with greater processing capacity.
Energy: more efficient solar panels, fast-charging batteries, and materials for energy storage.
Textiles: fabrics with antimicrobial properties or that repel liquids.
Nanotechnology is an invitation to look at the invisible and discover that there is also a world to explore there. Because when we understand how matter works at its most intimate scale, we can transform it and, with it, transform the world.
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