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The structural characteristics of nanomaterials

Physical properties

Published on 30 January 2017

Nanostructured materials offer some unique properties. However, to develop innovative uses for these materials, acquiring in-depth knowledge of the characteristics of materials structured at the nanometric scale is crucial. 

 

Observing and working with materials structured at the nanometric scale is the only way to acquire this in-depth knowledge. Near-field microscopes (atomic-force and scanning-tunneling) are used to observe matter at the atomic scale, and, in certain conditions, move individual atoms. Without these powerful microscopes, which are used with modelling and calculation software, exploring matter at this scale would be impossible. It is these tools that enable researchers to look at how a material is structured, identify its unique properties, and, as a result, come up with new uses for the material.

 

A nanoparticle moves very differently than a larger-sized particle. For example, when it comes to nanoparticles, thermal agitation plays a major—and sometimes the main—role in how particles position themselves. Thermal agitation is another way of saying that at the nanometric scale, all particles are constantly moving. And the higher an object's temperature, the more the particles that make it up are "agitated." In a crystal, for example, the atoms, which are bound together, are constantly vibrating. The frequency and amplitude of the vibration determine important characteristics like electrical conductivity or light absorption. In gases, all particles are also constantly moving, resulting in constant collisions between particles and difficult-to-predict overall movement.

 

Assembling atoms at the nanometric scale can create new and unexpected properties, often totally different from the properties of the same atoms assembled at the macroscopic scale. Useful "nano" properties include mechanical resistance, chemical reactivity, electrical conductivity, thermal conductivity, and fluorescence. The capacity to assemble atoms at the nanometric scale will ultimately open up new possibilities to create materials whose basic chemical, mechanical, optical, biological, and other properties can be substantially modified. Gold is a good example. At the macroscopic scale, gold is chemically inactive. However, gold nanoparticles measuring a few nanometers are chemically reactive. All types of materials—metals, metal oxides and ceramics, polymers, and carbon-based materials—can be enhanced in this way. These nanomaterials are characterized by original structures and properties.


Because nanomaterials have a wide variety of often-novel properties, the potential applications are equally varied. Using nanomaterials opens up a host of new possibilities. Nanomaterials can drive both incremental and disruptive innovations in a number of industries, from healthcare, energy, transportation, and construction to civil engineering, farming and food, electronics, and the environment. The technical innovations made possible by nanotechnologies are mainly due to enhanced material properties. Therefore, all industries from the most traditional (construction, mechanical engineering) to the most sophisticated (electronics, healthcare, space) are concerned.

Our societies are becoming increasingly dependent on a number of strategic raw materials. The mineral and construction industries and the high-tech industries all use precious metals like platinum, gold, and rhodium; rare-earth minerals; and elements like lithium, tungsten, cobalt, titanium, copper, tin, antimony, and germanium. Advanced and often multifunctional nanostructured materials are starting to be used as alternatives to these traditional materials in many of the systems and technologies we use every day. Nanomaterials will help reduce our dependence on increasingly-scarce resources by fueling the development of innovative products and better-performing technologies with lower environmental impacts. And more efficient product and materials lifecycles will further contribute to conserving resources by facilitating the 4 Rs: Reduce, Reuse, Recycle, Recover. This in turn will support the development of the circular economy.

 

The many reasons for developing nanomaterials include improving performance, reducing pollution, saving energy, and making more efficient use of and conserving natural resources.

 

Nanostructuring materials creates new properties that were once impossible to obtain from a single material, such as flexibility and resistance, for instance. The surfaces of parts can also be given special properties through nanostructuring. Coatings can be used to make mechanical parts harder and more corrosion-resistant and reduce friction. Cutting and machining tools are another area where nanomaterials can bring improvements. When used on tools to machine parts made from super alloys for the aeronautics industry, nanostructured titanium nitride coatings can substantially improve cutting speed and lengthen machine tool lifespans. In other industries, nanoparticles deposited on solid substrates can increase the speed of chemical reactions and make the reactions more selective. This can improve reaction yields, saving on raw materials and energy and reducing waste. 

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​Further Reading:


Overview of France's public hearings in 2009: Dossier du maître d'ouvrage sur des options générales en matière de développement et de régulation des nanotechnologies (2009) http://cpdp.debatpublic.fr/cpdp-nano/;

 

Nanotechnologies - Techniques de l'Ingénieur;

www.techniques-ingenieur.fr (Ref. ti155)

·         Nanosciences : concepts, caractérisation et aspects sécurité (Ref. 42194)

·         Nanomatériaux : synthèse et élaboration (Ref. 42195)

·         Nanomatériaux : propriétés et applications (Ref. 42635)

·         Nanotechnologies pour l'électronique, l'optique et la photonique (Ref. 42198)

·         Nanotechnologies pour l'énergie, l'environnement et la santé (Ref. 42514)

·         Annuaire des nanotechnologies (Ref. 42605)