Everyday Science: Nail polish is high tech.

Women are constantly judged for either wearing too much makeup or too little. There is no sweet spot because everyone has an opinion on what one must look like. This gets worse when you’re in an academic research setting. Makeup is almost considered a sign of nonchalance and messed up priorities. At one point in my life, I loved wearing nail paint and slowly the taboo around it in the lab got to me. Just recently, I started painting my nails again and it got me thinking how complicated nail paint formulation is. It is one of the most mechanically tested cosmetic products. It has to form a thin, pigmented film on the nail and then sustain all kinds of assault our digits are exposed to. Customers are constantly looking for durable formulations.

Nail paints contain a film-forming, explosive polymer called nitrocellulose dispersed in an organic solvent like ethyl acetate. Now, by itself, nitrocellulose is brittle and can chip off easily. So to improve adhesion and longevity, plasticizers like camphor are added. It is interesting to note that ping-pong balls are made with the exact same materials! Maybe I could make some nail paint with the box of orange ping-pong balls in my storage.

The 21st century has seen the miracle of gel nail paints. Gels are everywhere in nature. The precious collagen under our skin is a protein hydrogel. It means that many small collagen molecules can bind to each other to make a mesh that can hold water. The key to gel formation is that upon exposure to an external impetus, the free molecules can turn into a cross-linked mesh (like low temperature for making Jell-O). Gel nail paints are made of methacrylate monomers mixed with photoinitiator molecules.

When exposed to UV light, the photoinitiator molecules are activated. Then like conspiracy theorists, they go around activating others. Activated methacrylate molecules can bind to each other to form incredibly strong acrylate bonds, which is why after all the nail painting and UV cross-linking; the gel nail paints take forever to come off. Acrylate bonds are no joke.

Photo by Karolina Grabowska on Pexels.com

For people with careers that need their nails to look good all the time, the pay-off with gel nail paint is great. But for a non-serious diva like me, gel paints are just too much hassle. I wondered to myself if we can make gels under white light in the lab, why nail paints cannot be photoinitiated under normal light.

After deep diving into ingredient lists of various nail paints, I discovered that many nail paint companies falsely market their formulations as “gel” nail paints. Nevertheless, I also found that Chanel and Sally Hansen make nail paints that cure under white light. In fact, Sally Hansen trademarked its formulation as Miracle Gel. Both these formulations use TPO-L as a photoinitiator, which has an absorbance in the visible spectrum. These products promise to perform equivalent to the UV gel nail paints. Now I know how to splurge my savings next month.

I am excited to see how the nail paint formulation evolves. After all, we all need a splash of color in our lives.

WORDS: Purnima Manghnani.

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