These magical polishes are such fun. You could spend hours examining how the temperature in your fingers fluctuate and sometimes it can come as a surprise when your hand feels cold but your pinky is hot. Not only that but it feels like its a living breathing ombre.
The science is surprisingly complex for something as simple as nail polish, but I would like to simplyfy it.
Thermal polishes use pigments known as leuco dyes consisting of tiny little spheres called microcapsules
Inside the microcapsule there are three types of chemicals:
Dye . Weak Acid . Solvent
The dye - a coloured chemical undergoes a reversible reaction, combining with a H+ ion to become colourless
The weak acid - a colourless chemical, undergoes a reversible reaction, combining with the H+ ion to become colourful
So there are these two components fighting over who gets the H+
The solvent - controls which situation occurs! It has a melting point around the temperature you want the colour to change. When the solvent is liquid (hot), the H+ prefers to stick to the dye (colourless dye).Polish is mixed with the leuco dyes to make a rainbow of impressive colours When the polish is warm,the H+ prefers to stick to the dye making the leuco dye colourless and you only see the regular pigment, but when the polish is cool, the colour you see is a combination of the leuco dye and the regular pigment.