At the Miramón Technological Park in Donostia-San Sebasitan, the Cidetec Technology Centre is carrying out research in the field of electrochemistry, designing new thermochemical and electrochemical materials. At Cidetec they are mainly working with polymeric materials. Changes in the structure of these materials are effected to induce colour changes in them. Only prototypes are designed at this centre; no actual product manufacture takes place.
Thermochromic is the term for materials which, on subjecting them to a determined temperature, have the capacity to change colour. These processes may be reversible or irreversible. The reversible ones are those which, after undergoing the colour change, return to their initial colour when the temperature drops. On the other hand, irreversible materials are those which change colour just once and stay that colour - a process that is highly suitable for certain applications such as in frozen foods. With the aim of controlling the food standard or quality, the food wrapping material will change colour when the safe temperature limit is passed, i.e. the colour change gives a warning.
It is also possible to obtain colour change in certain materials independently of the temperature, using electric current to provoke the change. Materials with this property are called electrochromic.
These materials turn out to be suitable for other applications where temperature change is not required. They can be used, for example, in glass, changing its colour allowing less or more light to pass through from the outside. In the lenses of a pair of glasses, in car windows or even in the windows of our house, this property can have great uses. At Cidetec they are currently undertaking research on inducing colour changes in curved glass.