On the way to the future: nanotechnology

Photo: nanopool

These are the objectives: the ketchup bottle should be empty completely, the fruit should be protected from UV light, and the vegetables should keep for a long time. More and more, nano components are assisting in the attainment of these objectives. The razor-thin coatings and nano-particular additives in the packaging materials block unwanted gases, moisture and aromatic agents, improve thermal and mechanical characteristics and protect from UV irradiation. Thanks to nanotechnology, packaging is not only becoming more multifunctional, but also more intelligent. It is possible that smart labels will soon allow for new types of product and imitation protection.

Currently, there are about 400 to 500 nano packaging options on the market. Some processes have been in existence for several decades already. Foils and plastic bottles in particular often contain minuscule amounts of titanium dioxide or silica, which improve the barrier and protective function of the packaging and thus extend the shelf life of delicate foods. Sven Sängerlaub with the Fraunhofer Institute for Process Engineering and Packaging says that the improved characteristics could lead to material savings. It is also possible to add antibacterial characteristics to packaging by adding nano silver or nano zinc oxide, since these particles inhibit bacterial growth and propagation.

Many companies and institutes are researching further applications for nanotechnology, such as oxygen absorption in the material and non-stick coatings, among other things. KHS Plasmax GmbH coats the interior of PET bottles with glass (SiOx). This way, hardly any of the content of upside-down ketchup bottles sticks to the walls. Foil producer Klöckner Pentalast found out that nanotechnology could help to improve the scratch-resistance of foils, make the surfaces more conductive and improve thermal stability. According to estimates of the German Association for Environment and Environmental Protection (BUND), about 25% of all packaging will be equipped with nano-materials in the next decade.

Alexium Company, with locations in Perth, Australia, and Greer, South Carolina, uses nanotechnology to achieve significant effects with minimal use of material. The company’s process, originally developed by the U.S. Ministry of Defence, creates surfaces that are waterproof, oil-repellent, antimicrobial, anti-adhesive and UV resistant. The adhesion of nano particles is already being tested with textiles, paints and lacquers, packaging materials, glass and construction materials. Recently, Alexium celebrated a breakthrough with a nano composite carbon layer that makes nylon not only water-repellent and hard-wearing but also fire-retardant. This was impossible until now.

Photo: nanopool

Nanopool GmbH has developed an antibacterial liquid glass product. It is a nano silica layer that can easily and effectively be added to any surface. For this reason, the family-run company, headquartered in Hülzweiler, was presented with the Frost & Sullivan Award for new product innovation in Europe. “In addition to the antibacterial and safe characteristics of the nano finishing, the product offers many advantages: It is water and dirt repellent, and therefore the finished surfaces are easy to clean and maintain,” research analyst Ankit Ashokkumar Shukla remarked during the award ceremony.

Other advantages of the Nanopool layer: It is nearly invisible and therefore maintains the aesthetics of the original surface. In addition, liquid glass is heat and cold resistant. It remains stable in temperatures from -150° to 450°, which is why it can also be used in ovens and air conditioning units. The nano layer is applied with a cloth or a spray system. It is also possible to immerse the objects. “Nanopool has entered into successful partnerships with supermarkets and restaurant chains to protect surfaces from microbes, which in turn protects food from contamination,” commented Shukla.

However, nanotechnology critics are worried, because the small particles could be transferred from the packaging to the food or the environment. The risks are difficult to gauge, since materials in a nano-scale size sometimes react differently than in macro-scale size. To date, the registration and labelling obligation for packaging only relates to materials, but not their size. BUND considers that there is a need to act in this regard, because it has been shown in cell cultures that silica nano particles can disrupt the functions of the cell nucleus and thus the genetic constitution, the organisation states.

Since nano particles are so small, it is not clear which barriers they can cross. If they enter into the lungs, they may possibly also reach the brain. In February, Swedish researchers from Lund University published a study in the online journal “PloS One”, according to which nano particles from plastic affect the feeding habits and the lipid metabolism of fish. The carps eating nano feed moved slower, had less interest in eating and gained weight despite low amounts of food. The Chemical Industry Association points out, however, that no sweeping judgments should be made about the risks of nano-materials. A general nano law would therefore not be justified.

In the area of consumer protection in particular, there is another area of application for nanotechnology. Even today, large-size packaging or pallets include sensors that include product information for the retail market. A similar system could help shoppers in the supermarket, if all packaging were equipped with a nano sensor. Using a colour system, the products themselves could indicate whether the moisture or temperature levels have changed because there may be a hole in the packaging or the cooling chain has been interrupted.

In addition to protection from spoiled food, such sensors could also serve as proof of authenticity and protect from imitations of products and packaging. The family-run company Schreiner Group from Oberschleißheim is considering a 3D safety barcode, among other things. A silica cube with an edge length of only 30μm is supposed to be equipped with a 100nm-thin layer, into which an electronic beam drills 90,000 holes of varying depth in each side. Depth and position of the holes then create the encrypted code. The cube is not visible to the naked eye, but can be read with an electronic force microscope.