  
The Science Behind the Mug
Dragon LNG sponsor the Darwin Science Festival, which has helped us to design a Darwin Centre Science Mug!
The stylish blue mug changes colour with hot liquid to reveal logos and a photograph of a recent schools event.
The printing process
A coloured, heat sensitive coating is applied to the outside of the mug and a dye-sublimation process is used to print the images.
What is Dye Sublimation?
Tiny heaters inside the printer vaporizes the solid dye, which quickly solidifies onto paper. The paper contains a special ‘transfer toner’ which allows the image to be heat transferred onto the mugs.
What is the heat-sensitive coating?
The blue heat-sensitive coating becomes transparent and reveals the white mug and images underneath. As the mug cools it returns to its original blue colour.
The ability of a substance to change colour due to temperature is known as thermochromism.
Thermochromic paint was developed in the 1970’s and uses either liquid crystal or leuco dye technology. Liquid crystal is used for exact temperature changes, leuco dye is used for less accurate temperature changes and usually react within a 3°c range. Leuco dye technology is used in basic thermometers e.g. hot, warm, cold and in novelty items.
How does it work?
The thermochromic paint absorbs heat and as the temperature increases the molecular structure of the pigment changes.
This means that light is absorbed and emitted at different wavelengths. Our eyes see these wavelengths as colour, and so we see a change in colour.
The process is reversible and as the temperature decreases the colour returns to its original state.
Where else is thermochromism used?
Mood rings , battery testers, clothing and flat thermometers used in aquariums and for foreheads.
Exposure to ultraviolet radiation, solvents and high temperatures reduce the lifespan of leuco dyes. Temperatures above about 200-230 °C typically cause irreversible damage to leuco dyes
Whilst this product is safe to use in some dishwashers, it is not guaranteed to be dishwasher safe and we advise that it is washed by hand.
For more information visit Wikipedia.org
http://en.wikipedia.org/wiki/Thermochromism
All information here has been sourced from wikipedia |
