Clevertex - Grado Zero Espace Srl

of UV rays with wavelength 350-380 nm. Within 30 seconds after UV radiation, the colour of the fabric
disappeared. Sway UV® was used in T-shirts, polo shirts and jumpers.
C.T.I. also commercialised photochromic textile screen inks under DynaColor. The inks are off-white
when not exposed to UV radiation and gain colour as soon as they are exposed to UV light. They
claim that their ink is ideal for t-shirts and other apparel.
Electro-chromic dyes
Electro-chromic dyes and switches are used nowadays in combination with conductive fibres or
polymers for fashion applications to result in colour-changing fabrics.
Researchers at the department Fiber and Polymer Science at Clemson University, U.S., designed
fibres that can quickly change their colour, hue, depth of shade or optical transparency by application
of an electrical or magnetic field in 2001. They figured out that the visible radiation absorption and the
colour of electro- and magneto active oligomeric molecules can be changed by varying the electrical
or magnetic field. The research group made two approaches. On the one hand they modified the
surface of electrically conductive polymers as polyanilline, polypyrrole, polythiophene and
polythiophene with thiols. On the other hand, they attached molecular devices to the surfaces of
conductive polymers. However, research does not seem to go on [143].
Another possible chameleon technology uses microscopic capsules, embedded in a fabric, that
change colour when exposed to electricity. However, challenge to use this in real life environment is
the power source [144].
2.2.3 Applications in the clothing sector
2.2.3.1 Research projects and products
Thermochromic dyes
In the beginning of the 1990s garments with thermochromic materials were presented on a fashion
show to celebrate the 150 th anniversary of the Royal Society of Chemistry in London. Tight-fitting
garments were shown that are black in colour when hanging in the wardrobe. But, when wearing
them, they shimmer in rainbow colours. At this time, the chemicals company Merck, UK, modified the
materials so that they alter hue at different temperatures. Thermochromic pigments were launched on
the market under the brand name Licritherm by Merck.
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