Celebrating All Things Nano

October 9 is National Nanotechnology Day. Today we celebrate scientific advances that have made our world smarter, more sustainable, and healthier.

Last updated 9/30/2021

Some of the most marvelous developments of our time come from a single number: 10-9. This number represents all the unique properties, phenomena, and processes scientists have found at sizes between roughly 1–100 nanometers (nm). A nanometer is one-billionth of a meter, roughly the size of 10 atoms. To better understand the scale of a nanometer, consider a single strand of human hair: It’s approximately 80,000–100,000 nm wide. Scientists have been able take advantage of phenomena at the nanoscale to create smaller computers, faster processors, greener catalysts, and new ways to treat deadly diseases.  And it’s for this exciting reason that every year on October 9 (10/9), we celebrate National Nanotechnology Day!

Nanotech’s creative beginnings

Nanoscale materials have been used for centuries. Although they probably didn’t realize why it worked, 4th century Romans used colloidal gold and silver (metal particles sizes around 10–100 nm) to create glass that changed color depending on the angle light struck the surface. The art evolved into a science in the 19th century when scientists such as Michael Faraday studied how metal colloids produced different colors under certain conditions.

In the 1950s, research into colloids allowed for the development of many materials, including specialized papers, paints, and thin films. A 1959 talk by renowned physicist Richard Feynman planted many of the seeds for nanotechnology; it was essentially a thought experiment about the creation of nanomachines that could directly manipulate atoms. However, because nanoparticles are smaller than the wavelength of visible light (380–750 nm), they cannot be studied with a typical light microscope or other conventional equipment. Therefore, much of the work concerning nanoscale materials remained theoretical until 1981, when the invention of the scanning tunneling microscope enabled researchers to create images of actual nanoparticles.

In 1985, Richard Smalley and his colleagues reported the discovery of Buckminster fullerene (C60, aka buckyballs). A brand-new allotrope of elemental carbon, buckyballs exhibited exceptional strength and stability for molecules of their size, as well as unusual electronic properties. Within two years, hundreds of scientists were turning their attention to C60 and exploring other nanoscale materials. The field has been rapidly growing ever since.

Buckminster fullerene or buckyball
Buckminster fullerene (C60), aka buckyball, is a hollow sphere of 60 covalently bonded carbon atoms. Discovery of this form of carbon, with its unusual electronic properties, exceptional strength, and stability, set the stage for the field of nanotechnology.
Image credit: Thinkstock.com

According to the American Society of Mechanical Engineers (ASME), the top five current trends in nanotechnology research are stronger materials and higher strength composites, scalability of production, more commercialization, sustainability, and nanomedicine. For example, the tensile strength of carbon nanotubes and graphene (single atom-thick sheets of carbon) is about 100 times that of steel. Consequently, carbon fibers and nanotubes have found commercial applications in things like helmets, bicycle frames, and car frames (e.g., the Lamborghini Aventador chassis).

Why smaller is better

Nano-sized particles have many different properties from their bulk counterparts, especially metals and inorganic compounds. For one thing, the ratio of atoms on the surface to those inside the nanoparticle is much higher. This means more surface atoms are available for reacting (think more powerful catalysts), and they have fewer interatomic interactions holding them in place (think reduced melting points). Gravity, being mass-dependent, becomes much less important than electromagnetic forces, which support the formation of colloids.

Plus, in metal and semiconductor nanoparticles, properties like color, fluorescence, electrical conductivity, and magnetic permeability become dependent on the precise particle size. In bulk materials (> 100 nm), the highest occupied orbital and the lowest unoccupied orbital of individual atoms overlap and blend together to make energy bands, wherein the gap between the bands—called band gap—governs the material’s optical, electronic, and chemical behavior.

But smaller than 100 nm, the bands are still quantized (unblended), and the size of the band gap increases as the particle size decreases. With such a phenomenon, you can “tune” the properties of the material by creating different particle sizes

Infographic: Nanotechnology
By Andy Brunning
Credit: Chemical & Engineering News

Putting nanotech into tech

Nanoscience is ideal for a number of technological applications that improve our daily life. Here are some prime examples:

Huge medical advances from nanomaterials

Nanomaterials are the right size for medical applications, since much of biology takes place at a nanoscale. Cell membranes are typically 5–10 nm thick, mitochondria are 1–2 nm long, and water molecules are about 0.2 nm wide.

Here are some amazing ways nanotechnology has improved medical diagnostics, monitoring, and treatments that protect and prolong human life:

Important Risk Considerations

According to the National Institutes of Health, nanomaterials will be have a tremendous impact on society: improving energy usage and transmission, new modes of computing and data storage, new ways to monitor the freshness of food, constructing lightweight, wear-resistant materials for transportation and building, and safer, more effective consumer products. But as with any technology, nanotechnology comes with a price.  Working safely with the nanomaterials is a challenge for the exact same reasons as they are exciting—their properties and their size.

Studies show that nanomaterials are easier to inhale and may even stick around in the lungs for a while, raising concerns about the development of airway diseases. And as nanomaterials are used more and more in clothing, beauty products, and electronic devices, unintended release in the environment and bloodstream are concerns that researchers are actively studying to safeguard life and the earth

For more information about nanotechnology, the latest news about nanotechnology, and a variety of helpful resources check out acs.org/nano and nano.gov.

Examples of nanomaterials

Nanotechnology encompasses both particles that are less than 100 nm and materials with repeating structures in the 1 – 100 nm range. Here are some examples.

Quantum dots of Ag4Br4 (red/white) inside the pores of an aluminosilicate zeolite.
Quantum dots of Ag4Br4 (red/white) inside the pores of an aluminosilicate zeolite.
Credit: Chemical & Engineering News

Gold iridium catalyst
Gold/Iridium (green/blue) nanoparticles on a surface of titanium dioxide (white and gold).
Credit: Chemical & Engineering News

The aluminosilicate zeolite, ZSM-5, a common catalyst in petroleum refining
The aluminosilicate zeolite, ZSM-5, a common catalyst in petroleum refining.
Credit: Wikipedia

Metal organic framework  composed of metal ions with triazolate linkers
Metal-organic framework (Co is purple, C is gray, N is blue, O is red, Cl is green, and H atoms are omitted) composed of metal ions with triazolate linkers.
Credit: Chemical & Engineering News

Check out these fun ideas to investigate the advances in nanotechnology and how it is impacting our everyday lives on National Nanotechnology Day.

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