Gothenburg, Sweden--Polymer technology researcher Christian Müller of Chalmers University of Technology has found a way to differentiate between designer clothing and knockoffs: he has produced a photonic textile (http://www.laserfocusworld.com/articles/print/volume-48/issue-04/features/smart-photonic-textiles-begin-to-weave-their-magic.html) technology that consists of threads with unique optical properties that can be used to create invisible patterns in fabrics that are only visible under polarized light. An Applied Physics Letters paper (http://apl.aip.org/resource/1/applab/v101/i17/p171907_s1?isAuthorized=no) details the technology.
According to Swedish Customs, trade in counterfeit and pirated goods has exploded the past few years in Sweden, the EU, and globally. The situation impacts companies, their employees and unknowing consumers. It is often difficult to see the difference between a genuine garment and a knockoff.
The partially invisible thread is made of polyethylene and a dye molecule that absorbs visible light. The thread can be weaved into a pattern that is invisible to the naked eye, but which can be seen using a polarization filter. "The production process itself is uncomplicated," he says. "Clothing manufacturers could start using the thread right away to put a signature pattern in their garments. The equipment needed to see the pattern is fairly simple, and is already in place at Swedish Customs, for example."
The invisible thread can be created using several different dye molecules and several different synthetic fiber textiles such as nylon. The dye molecule can also be bonded to natural fibers such as wool and silk. The technology can be used both for clothes and for different types of expensive specialty fabrics such as the textile used in vehicles and caravans, the idea being for a brand to be associated with its own special combination of textile fibers and dye molecules.
"It is very difficult for pirate manufacturers to copy the unique combination," says Christian Müller. "They can obtain the equipment needed to read the pattern and ascertain the optical spectrum produced by a specific signature, but they cannot know which combination of components will produce the specific spectrum. And there are loads of different dye molecules available for use."
There is a similar technology available for creating invisible patterns on banknotes, which is used in Switzerland. From a long term perspective, Christian Müller's discovery could also be used to manufacture "smart textiles", such as clothing that changes colors based on electrical charge.
SOURCE: Chalmers University of Technology; http://www.chalmers.se/en/news/Pages/Invisible-pattern-can-put-a-stop-to-counterfeit-designer-clothing.aspx
IMAGE: Using invisible thread can help clothing manufacturers create a logotype that is part of the actual fabric and that only becomes visible under polarized light. The technology produces a specific optical spectrum that is very difficult for pirate manufacturers to copy. (Image credit: Chalmers University of Technology)
