What are the mechanical properties of nanomaterials

Nano-Portal: Safe working with nanomaterials

Silver ions have an antimicrobial effect. Silver nanoparticles give off (due to the surface effect) larger amounts of silver ions than macroscale silver. Thus, smaller amounts of the starting material are necessary to achieve an antimicrobial effect (Greßler et al. 2009).

Some nanomaterials (especially carbon compounds such as graphene and carbon nanotubes) have extreme tensile strength and stability at low weight. If CNTs are used in composite materials, they enable weight savings with constant or increased stability. Other nanomaterials (e.g. silicon dioxide) are applied to surfaces and thus increase their scratch resistance (Greßler et al. 2011).

Quantum effects occur, for example, with quantum dots. These consist of around 10,000 atoms of a semiconducting material and do not have a continuous, but a discrete charge distribution. The resulting physical properties enable a variety of applications, for example in photovoltaics, digital data processing or the generation of light (source: Welt der Physik).

The changed optical properties of nanomaterials are used in a variety of applications: titanium dioxide nanoparticles are - in contrast to macroscale titanium dioxide - transparent and enable effective UV protection without leaving any discolouration. Other nanomaterials such as silicon dioxide are used in anti-reflective, IR reflective and absorption layers. In photovoltaics, nanotechnologies enable increased efficiency by optimally adjusting the band gap (Möller et al. 2013). The optical properties of nanomaterials change not only from macro to nanoscale shapes, but also within the nanoscale range: The color of gold nanoparticles changes depending on the particle size.

If ferromagnetic materials are severely comminuted (particle size less than 100 nm), they consist of a single so-called Weiss region (region in which all atoms have parallel magnetic moments) and have a high magnetic moment. The magnetization of such particles can easily be canceled. One speaks of superparamagnetism. Superparamagnetic nanoparticles allow the production of ferrofluids, which are used, for example, in the medical field (hyperthermia treatment of tumors) (SNC 2010).

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