86 | colour- and optically-changing smart materials
Ma^kfhpZee Monosmart material | Monosmart application Colour- and optically changing smart material: THERMOCHROMIC PAINT (LIQUID CRYSTALS WITH A SYNTHETIC BINDER) Indication of temperature differences (weather) by colour change
Sigmar Polke, Germany Wall installation | Musée d’Art Moderne de la Ville de Paris, ARC, Paris, France (1988) Two years after completing his Hydrowand for the German pavilion at the XLII. Biennale in Venice the artist covered a convex-curved wall with a large area of temperature-sensitive, colour-changing paint composed of liquid crystals and a synthetic binder. Through the use of three different types of liquid crystal that changed colour over three different temperature ranges, the Thermowand was meant to show the daily path of the sun by reacting to the sunlight falling upon it. The thermochromic dispersion paint used liquid crystal substances specifically selected to cover the temperature ranges 20°C to 22°C, 20°C to 25°C and 27°C to 33°C. The canvass for his painting was a damp-proof aluminium membrane glued to the wall. The paint contained toluene. It was therefore poisonous and had to be applied wearing a breathing mask. The possible colour spectrum ranged from black (cold, < 20°C) through violet-red, red, yellow, yellow-green and green-blue to turquoise (warm, > 26°C). The plan was that the roof construction would create a permanently changing “shadow drawing”. As the sunlight did not manage to reach the Thermowand as planned, an infrared lamp was installed to demonstrate how the wall worked.
Thermowand: wall with the applied thermochromic paint in the cold state (black). | Detailed photograph of paint coatings at different temperatures.