Imagine a single-coloured piece of cloth that suddenly displays a colourful pattern when the ambient temperature changes. Upon further temperature change, a completely different pattern shows up. Doctoral student Marjan Kooroshnia at the University of Borås has developed methods that enable just such changes.
“My research was conducted by undertaking a series of design experiments using leuco dye-based thermochromic inks, which resulted in various working methods and two pedagogical tools in the context of textile design,” she says. “Now I hope that other designers and researchers can further develop these methods. In my research, I have also prepared two educational aids that can facilitate communication regarding, understanding of, and design with thermochromic inks, but still we need to have both terminologies and a thermochromic colour system in order to understand how thermochromic inks behave in relation to other static pigments and varies temperatures.”
Marjan Kooroshnia began her research on already existing descriptions of leuco dye-based thermochromic inks; below their activation temperature they are coloured, and above their activation temperature they are clear or have a light hue. In addition, they are usually blended with static pigments, allowing them to change from one colour to another. After a lot of testing in the printing lab, she managed to mix the inks so that they looked similar when they were in a non-heated state and they change to different colours as result of increasing temperature.
Then, she explored thermochromic inks with different activation temperatures in order to create a wide spectrum of colours that would appear at different temperatures. She used thermochromic inks with activation temperatures of 27, 37 and 47°C to create a dynamic pattern that colour changing effects that appear in sequence due to increasing temperature.
Marjan Kooroshnia has also created two educational tools that can facilitate communication regarding, understanding of, and design with thermochromic inks. One consists of different colour swatches printed with static pigment that can be placed along an artificial thermometer. Another is thermochromic colour sample spectra where thermochromic colour transitions are demonstrated step by step from non-heated, to heated, and back to a cooled state. In addition, she has begun to create a thermochromic colour system, which will be used to teach and study thermochromic inks. So far, one suggestion for the system in a shape of pyramid works the best, but it needs further development.