liquid crystal material itself is micro-encapsulated - i.e., contained within microscopic spherical capsules typically just 10 microns in diameter. Billions of these capsules are mixed with a suitable base to make thermochromic printing ink or, for example, with plastics destined for injection moulding. The thermochromic pigment in the Smart
<P>A self-adhesive 150 x 150mm sheet printed with a thermochromic liquid crystal ink which changes colour when heated above 27°C.</P><P>A sample pack is also available, containing a 50 x 150mm thermocolour sheet and a 1m length of resistance wire which can be attached to the back of the sheet and used as a heating element when a small current is passed through it.</P> Liquid Crystal is one of the most beautiful yet versatile smart materials around. It is a living protein and is very sensitive to temperature changes. It responds to temperature between 24C and 29C, and transitions between the colours red, green and blue.
Thermocolour sheets are self-adhesive and consist of a thin layer of liquid crystal that has been printed on to a black background. Liquid Crystals are organic chemicals with twisted helical molecular structures, which expand, or contract with increases or decreases in temperature, not unlike a spring.
A change in the crystal temperature can result in a change of spacing between the layers and therefore in the reflected wavelength. The color of the thermochromic liquid crystal can therefore continuously range from non-reflective (black) through the spectral colors to black again, depending on the temperature. Typically, the high temperature ...