How do nail polish drying drops and sprays work?

Pergunta:

Como funcionam as gotas e sprays secantes de esmalte?

Resposta:

Para entender como eles funcionam, você deve entender como o esmalte seca. Primeiro, você precisa saber o seguinte: As moléculas são realmente pequenas. Muitos milhões de moléculas cabem na cabeça de um alfinete. Mesmo os microscópios mais avançados jamais poderiam vê-las diretamente ou observá-las em movimento. Somente dispositivos especiais altamente avançados podem chegar perto de fazer isso.

So, we’ll just pretend to have a microscopic vision and can see molecules. If you use this microscope vision, you could look down into the freshly applied nail polish layer and see that there were millions of molecules shaped much like playing cards used in games. These cards would be mostly standing on their edges and piled on top of each other to form many layers. These molecules are not just floating free in a solvent. Instead, they are randomly stacked to form a crazy-looking “house of cards.”  This house of cards would be only semi-stable and would slowly fall apart as the solvents evaporate.

As the polish dried, this house of cards would begin to fall down in slow motion until all the cards are lying flat on their sides. In other words, as the nail polish dries and solvents evaporate away, these tiny “playing-card-shaped” thickener molecules settle onto the nail plate, on their sides, lying as flat as possible. This is one reason why dry nail polish forms a thinner layer than when wet. Some of this loss of thickness is due to the solvents evaporating away.  Most of it is due to thickener molecules settling into new positions and flattening against the nail plate in piles. 

How do nail polish drying drops and sprays work? They contain ingredients that target the thickener molecules to cause their “house of cards” to fall very, very rapidly, instead of in slow motion. As the thickener molecules pile up on the nail plate, this pushes the solvents to the surface. The solvents then blend with ingredients in the drops or spray and evaporate away.

Now you can see why I first explained how traditional, solvent-based nail polishes dry. All that a nail polish dryer does is to slightly speed up the process. These dryers do not completely remove the nail polish solvents, so the layer of nail polish will still take a while before it is fully hardened. Even so, polish dryers will knock a good ten to fifteen minutes from the initial drying process.