Nanotechnology for Textiles, Scents and Flavours
The textile industry is an early adopter of new ideas and technologies. Textiles are not only for the fashion conscious - they have important applications in the aerospace, automotive, construction, healthcare and sportswear industries. Already on the market are socks and leisurewear with embedded silver nanoparticles that combat odour through killing bacteria – and this capability has been extended successfully to wound dressings. Several brands of clothing, including some designer labels, have incorporated self-cleaning and stain repellent nanotechnologies, very convenient for school clothes - and, of course, the less a garment needs to be washed, the more energy is saved! More glamorous applications include embedding gold nanoparticles into natural fabrics such as wool. The gold nanoparticles impart soft colours from pale soft greens, to browns and beiges, depending on the particle size and shape. These colours are stable, and may even provide some antibacterial properties to the fabrics, as an added bonus!
Across the globe a tremendous amount of research is taking place in electrospinning techniques. The spun, polymer-based nanofibres can be 'loaded' with different additives which could be nanoparticles, enzymes, drugs or catalysts. Some combinations can be antibacterial and sprayed on to wounds as a kind of healing 'web', others can be conductive or even form filters or membranes.
Scientists are also working on nanoelectronic devices that can be embedded into textiles to provide special support systems for individuals in dangerous professions or sports. Some garments can now provide life-signs monitoring, internal temperature monitoring, chemical sensing and also power generation and storage to enable communication with the outside world. Garments with this kind of technology can be vital for the safety of say firefighters working in dangerous situations in isolation from their colleagues, or even for skiers or their rescuers to give early warning signs of hypothermia.
In some establishments, research is ongoing into man-made nanofibres where clay minerals, carbon nanotubes or nanoparticulate metal oxides are used to impart new properties. These properties provide halogen-free, flame retardancy for a fabric, increased strength and shock-absorbency, heat and UV radiation stability, and even brighter colouration! Other work is ongoing in the very exciting area of inkjet printing onto textiles. This is opening up many possibilities, not just for the customised or localised printing of textiles to an individual design, but inkjet techniques can be used to create flexible electronic materials, sensing materials, and even the materials of the future with printed-on displays!
Scents and Flavours
A surprisingly interesting and lucrative field for the application of nanotechnology is in encapsulation and delivery technologies, especially for flavours and fragrances. These technologies were first developed for the delivery of pharmaceutical drugs, and have now found new applications in foods and household products. Encapsulation is an ideal way to improve the attributes and performance of a less-than-stable substance that might be affected by light or air, or have a tendency to sediment. Encapsulation gives active ingredients a longer shelf life, stability and protection from harsh processing environments so they can be delivered in a perfect state at 'the moment of consumption'! For the food industry, it is a way of delivering enhanced taste, or ensuring that daily doses of vitamins and minerals are met – this is discussed in more detail below. In household products, nano encapsulationtechniques can aid in the deposition of a cleaner or polish onto a surface such as a floor or counter; they can provide long lasting scents in household fragrances, and the slow release of enzymic and other agents in washing machines and dishwashers, helping reduce energy and water use.