Thermoplastics are non-crosslinked polymers. Their central feature is that they are
moldable. Typical examples of thermoplastic polymers are Polyolefines, Polyesters,
Polyamides, Polyacrylates and Polyvinylchloride. Most of these polymers are stable
in the molten state. Thus they can be treated by extrusion technology or injection
molding. During these processes high temperatures and strong mechanical stresses are
applied. Thermochromic pigments developed in our laboratory can be already added to
the raw polymer before the extrusion process. In this way, a technology compatible
production of thermochromic foils and injection molded plastics in which the
thermochromic dye is evenly distributed in the total polymer volume could be
demonstrated for the first time. Switching temperatures from 0°C to 70°C and a
variety of colors are available at the moment, whereby the color changes can take
place reversible or irreversible.
A vacuum deposition of transparent electrodes on the thermochromic polymer material
in an ultra high vacuum of about 10-7 Torr enables a hybrid active-passive
color switching. Thermal or electron beam techniques have been successfully used for
the preparation of the electrodes.