NanoSphere-treated fabric from Swiss manufacturer Schoeller has become the first product to qualify for the 'Nanotechnology' quality label.
It has passed the complete sequence of tests set by the German Hohenstein Institutes to achieve this first.
In October 2005, Germany's Hohenstein Institutes announced that in conjunction with NanoMat – a network of various research institutes and leading suppliers of nanomaterials – a definition of nanotechnology to be applied to the textile sector had been established.
While included in the advertising claims of many textile manufacturers, there was no uniform definition of the term 'nanotechnology', leading to considerable confusion amongst retailers and consumers, NanoMat said, and because the majority of products claiming nanotechnology benefits simply exist in theoretical form, or at best as prototypes, the following definition was created to relate back to the nanoscience involved:
'Nanotechnology comprises the emerging applications of Nanoscience. Nanosience is dealing with functional systems based on the use of sub-units with specific size-dependent properties of the individual sub-units or of a system of those'
The Hohenstein quality label is already established in the area of wear comfort, and is now being expanded as an indication of nanotech benefit.
In order for a textile product to be able to use the Hohenstein quality label, however, it will not be sufficient for nanoparticles (1 nanometre = 10-9 m = 0.000001 mm) to be incorporated within the fibre or for the fibres to be enclosed in a nanoscale coating (nanofilm).
Rather, the nanoparticles or nanolayers in or on the textile must be systematically arranged and demonstrably result in a new function.
In addition, the nanotechnology must only be perceptible to the wearer by means of a demonstrably improved function, and have a negligible effect on the textile properties.
Textile technological parameters tested in addition to the nanofinish are resistance to care treatments, any effect on health, and wear comfort.
"Up to now, the Schoeller product is the only one to pass the complete test routine without fault," Dr Jan Beringer, head of Intelligent Textiles in the Textile Services and Innovations Department at Hohenstein Institutes and responsible for the new Hohenstein Nanotechnology Quality Label.
In its study, Hohenstein analysed the material components and tested the dirt repelling properties, the effect on the skin, the abrasion resistance and resistance to washing. Even after 5,000 cycles in the abrasion test, which corresponds to practical wear of clothing textiles, the structures in the micro and nano area of the first Schoeller samples tested were still clearly recogniseable. This is due to the fact that Schoeller has developed a special coating matrix for NanoSphere technology which fixes the nanoparticles in such a way as to ensure that they cannot become detached and are firmly anchored into the surface of the fabric.
Top results were also achieved in water and oil repellency. In its new state, the textile sample displays a very high level of hydrophobia, very good repellence of oil-water emulsions and very good oleophobia - in an AATCC test, the oil grade 8 (highest possible score) was recorded.
Even after 50 washing and drying cycles and reactivation by brief ironing NanoSphere, still achieved the oil grade 7.
Skin tolerance also tested positively and NanoSphere is therefore the very first nano-material to be permitted to use the new quality label, having passed the complete Hohenstein test procedure.
"In today's market there are so many empty promises and the market is becoming very uneasy in its reaction to everything that calls itself 'nano'," says Schoeller CEO Hans-Jürgen Hübner. "This neutral quality label from the independent Hohenstein Institutes is therefore a good thing. First, it tests for genuine or fake and then determines important utility values. It therefore supplies a lot of practical information and acts as proof of quality for the consumer.
"The consumer now recognises that this is a label which can be relied on, which is why we decided to submit ourselves to testing."
The authenticity of nanotextiles can only be analysed, he explained, by using expensive special appliances such as atomic force microscopes (AFM) or high resolution reflection electron microscopes (REM), which is why the term 'nano' is being so extremely overused.
