Chemistry in the studio – but without a lab coat

You know the moment: apply the gel, put your hand under the lamp, and you're done! But what exactly happens?

In this article, we explain the polymerization of UV gel – understandable for anyone who would like to know a little more.

What is polymerization anyway?

Polymerization is a chemical process in which many small molecules (monomers) combine to form long chains (polymers). This is exactly what happens when gel cures on the nail.

What exactly happens during the polymerization of UV gel?

When you apply UV gel and cure it under the lamp, a complex chemical process takes place in just a few seconds. It transforms a liquid or gel-like substance into a hard, stable plastic – the polymer.

The three main ingredients in UV gel:

1. Monomers
   → Small molecules that can join together to form chains.
   (e.g. urethane acrylate, methacrylate compounds)

2. Oligomers
   → Shorter molecular chains that make the gel more stable.

3. Photoinitiators
   → These start the reaction as soon as they are exposed to UV or LED light.

This is how polymerization works – step by step:

1. Light hits the gel
   The UV or LED lamp emits light at a specific wavelength (e.g. 365–405 nm).

2. Photoinitiators absorb the light
   These molecules are light-sensitive. They are activated by light.

3. Start of radical formation
   The activated photoinitiators release so-called free radicals – extremely reactive molecules.

4. Chain reaction begins
   These radicals attack the double bonds of the monomers – the monomers “hook” together to form long chains.

5. Networking is created
   The chains also connect with each other crosswise to form a three-dimensional network = solid, hardened gel .

Why does it sometimes get warm?

The reaction is exothermic – that is:
Heat is released when the molecules combine.
Especially with thicker layers or highly reactive gels, this can lead to a heat surge (so-called "heat spike").

Good to know:

• UV and LED gels differ in the photoinitiators → therefore they require different lamp types.

• If the lamp is too weak or old, the gel will not harden completely → this can lead to lifting or allergies.

• The dispersion layer gel (“sweat layer”) is a by-product of polymerization – it contains molecules that have not fully reacted and is removed after curing.

In short:

This is how it works in the nail salon:

1. The gel contains monomers + photoinitiators

2. The UV or LED lamp activates the photoinitiator

3. This triggers the reaction of the monomers

4. The gel hardens – a solid polymer network is formed

Result: A shiny, firm nail surface that lasts!

That's why it sometimes burns

The resulting reaction is exothermic — heat is released . If applied thickly or if the nail is sensitive, it may sting briefly.

Tips to prevent burning:

• Work in thin layers

• Use high-quality gels with controlled heat development

• If necessary: briefly remove from the lamp & then cure again

And what about security?

• Modern gels are highly developed & tested

• Important: Good ventilation in the studio

• Gloves or dust extraction help with filing work