After seeing in February the “Prospects of nanotechnology in the solar energy sector”, let’s now focus on those for packaging.
Due to tight legislations and importance of consumers’ perception, packaging is a field driven by incremental improvements rather than by sudden revolutions. As such, new technologies are slowly penetrating and the first uses of nanotechnology in packaging are nothing but new. Indeed, in the 60’s, metallization was developed as an alternative to aluminium foil to improve resource efficiency while maintaining barrier properties. Aluminium layers at nano-scale became established in the 1970s and 1980s while silicium oxides layers followed in the 1990s ¹.
Currently identified benefits of nanotechnology for food packaging are very extensive. Besides being a key enabler of Smart & Intelligent Packaging, eg. by being used in nano(bio)sensors to indicate quality of foodstuffs, let’s consider further nanotechnology applications to help improving materials to reduce product waste:
by imparting easy emptying feature to the packaging to avoid as much as 30% of the product waste at the end of life of packaging such as tubes.
by extending shelf-life of packed goods thanks to antimicrobial properties of selected nanoparticles coated on films surfaces.
by improving polymers performance such as barrier to gas permeation or UV but also mechanical properties, durability, temperature resistance, etc.
The liquid and viscous products residues in packages can be tuned by decreasing the packaging surface affinity for the packed substance. Alternatives based on nano have emerged since the use of Teflon in packaging is hindered due to its high cost, processing temperatures and low acceptability/recyclability because of its fluorinated content. Chemical vapor deposition (CVD) can be used to texture PET resulting in a hydrophobic layer.Electrospray has also been used to create superhydro/oleo/amphiphobic surfaces using polystyrene (PS), titania or graphene among others. Recently, the MIT developed the first permanently wet slippery surface that can be used for easy-to-empty packaging (LiquidGlide, see picture).
The most studied nanomaterials to improve the barrier properties of polymeric nanocomposites are layered nanomaterials such as clays, an indeed quite natural material used since the dawn of humanity. Furthermore, more recently and trendily, graphene was used to obtain semi-transparent barrier layer.
The incorporation of active substances (e.g. antimicrobials and antioxidants) within the package polymer matrix or as coatings are used in the development of active packaging. Antimicrobial nanocomposites or nanocoatings preserve the packaged foodstuffs longer by inhibiting microbial growth generally using for example titania nanoparticles, which are becoming more and more common in eg. textile or medical applications.
As seen, number nanotechnology based solutions have emerged but still fail a more widespread use due to cost, regulatory compliance, environmental, safety or societal issues. Although some studies demonstrated that nanoparticles do not migrate in the packed food, the safety concerns, consumer-perception driven technology acceptance and good dispersion of nanoparticles in the polymer are significant obstacles for the greater use of nano in packaging. All these challenges are tackled with an industrial perspective in the OptiNanoPro project coordinated by IRIS.
Keen to toast for nano with graphene packed beer? Graphene deposited on plastic bottles using microwave plasma led to over 10-fold decrease in the oxygen permeation allowing to replace glass bottles².
¹ H.-C. Langowski, Trends, Sustainability, Acceptance: Challenges for Plastic Packaging, Kunststoffe international 2015/11
² C. Casiraghi, J. Robertson, and A. C. Ferrari, “Diamond-like carbon for data and beer storage,” Materials Today, vol. 10, pp. 44-53, 1// 2007
Original Source: http://www.iris-eng.com/tiny-but-full-of-promises-2nd-episode-the-promises-of-nanotechnology-in-packaging/