As The Toast searches for its one true Gal Scientist, we will be running a ton of wonderful one-off pieces by female scientists of all shapes and sizes and fields and education levels, which we are sure you will enjoy. They’ll live here, so you can always find them.
I got my first gel manicure last week and it was AWESOME. Sure, it looks amazing and hasn’t chipped all week but it’s the chemistry that really blew my mind.
Chemistry gets a pretty bad rap. In school it’s a class to survive rather than enjoy. In the news any mention of chemicals is usually a safety warning, something to avoid rather than celebrate. Like nail polish, fear of chemicals is also aggressively marketed to women, particularly through advertisements for “natural” or “chemical free” cosmetics. This makes worrying about the safety of chemicals seem more feminine, perhaps a bit irrational, and definitely unscientific.
Some scientists like to make clever jokes about how clever they are for not falling for “chemical free” marketing. Yes, “chemical free” is kind of ridiculous and technically impossible, but I also understand the underlying sentiment of wanting to find products made with better, more sustainable, or less harsh chemicals. As a scientist I also understand just wanting to learn more about the ingredients in the products that I use. What’s unscientific about wanting to know how things work and how they’re made?
So let’s start with the chemistry of regular nail polish, because it is made of things like explosive cotton and fish scales. The main ingredient in regular nail lacquer is nitrocellulose, a mixture of an indigestible plant fiber and the stuff that makes nitroglycerin or TNT explode. While it was originally used for things like gunpowder and blast mining in the 19th century, today we also use it in all sorts of other things like ping pong balls and the sticky stuff that holds rows of staples together. When it’s dried on your fingers it doesn’t pose much more of a threat to your safety than your own fingernails, which you shouldn’t be lighting on fire anyway.
In the bottle, the nitrocellulose is dissolved in a chemical solvent called ethyl acetate. This solvent is what gives nail polish its “chemical” smell, because it evaporates very quickly and reaches your nose first. Once it’s painted on the nail, the solvent gradually evaporates away entirely and the nitrocellulose is left behind, drying into a solid film on your nail. The same solvent molecule is used to make non-acetone nail polish remover, which simply re-dissolves the nitrocellulose back into a liquid so it can be wiped off.
Along with the nitrocellulose, the solvent, some pigments and plasticizers, nail polish might also include “pearl essence” to give it a nice shiny look. Pearl essence shines like the beautiful silvery iridescence of fish scales because it is made out of ground up beautiful iridescent fish scales. Now that we’ve decimated many fish populations with overfishing, cheaper mineral alternatives are more commonly used.
Gel nail polish works in a totally different way. Unlike nitrocellulose polish, which will dry out gradually as the solvent evaporates, gel polish will never dry unless it is activated by ultraviolet light. Like a superhero gaining super strength after a dose of radiation, a “photo-initiator” molecule mixed into the polish can absorb the UV energy, break itself in half and make two super-charged molecules. These charged molecules are called free radicals — a type of chemical that gets an especially bad rap, because that extra energy can be used to break all sorts of chemical bonds where it’s not supposed to. In the nail polish, the extra energy jump-starts a chain reaction that transforms the liquid polish into a hard layer of plastic within seconds.
In most gel polishes, the photoinitiator is benzoyl peroxide, which is also a common ingredient of over the counter acne creams where its job is to peel the top layer of skin off your face. In nail polish it’s mixed with the liquid form of a plastic called methacrylate. The free radical from the benzoyl peroxide pushes electrons around in the liquid methacrylate monomers (“mono” = single, “mer” = part) so they form bonds with each other and create a solid polymer (“poly” = many). Methacrylate in its many different forms is used in all sorts of other applications where strong and flexible plastics are needed, like for fixing broken car windshields or as BONE CEMENT in orthopedic surgery.
The chemistry involved in balancing the amount of methacrylate monomers and benzoyl peroxide can be tricky. The Nail Systems International website describes the process with an analogy that us women-from-olden-times can understand: “think of how different a recipe would be if you altered the number of eggs or cups of flour.” Too little photoinitiator and the plastic will take so long to harden you might get a sunburn from the UV. Too much and the reaction will happen so quickly and generate so much heat that it could burn your fingers. Just like baking.
Condescending explainer websites are of course not the only gendered aspect of nail polish chemistry. Beyond chemophobia and cosmetics, nail polish is often seen as decorative and frivolous, superficial “girl stuff.” But when we look closely at the molecules in the list of the ingredients, we find that nail polish is also totally hard core.
So next time you’re at the salon and trying to decide what kind of polish you want, just think: gunpowder or bone cement? fish scales or radioactive super-power?
Tags: beauty, Christina Agapakis, gal science, science
This is AWESOME. I’ve always wondered how nail polish worked exactly even though I knew some of the various ingredients it was made out of. I also recently got my first gel manicure and that shit is a miracle. I kept enthusiastically describing it to everyone, and not many people seemed to think it was as amazing as I thought – probably because ugh, girl stuff for girls. SCIENCE.
I’ve never used gel nail polish – what does it feel like as your nails dry? Given the chemistry described it seems like it would be a different sensation than regular nail polish. (I was talking about evaporative cooling with someone & said “you know, like how your fingers get cold when nail polish is drying” – but he had never used nail polish, so it wasn’t such a helpful example.)
Is that the same feeling you get after pouring meths on your hand to make your callouses more callousey?
I’ve never heard of that! I guess you get it from anything that evaporates quickly from your skin. I always thought it was particularly distinctive on nail beds but callouses are kind of similar – hardened up skin. I don’t think I’ve had polish on my nails in a decade but I sure remember that sensation.
It’s what we were told to do to toughen our hands up for rowing. Not quite sure how it works exactly, but the meths evaporates and somehow hardens the skin somewhat? Sounds really dubious, but it works! Helps cut down on the blister stage.
It’s been over 10 years since I did that now, but yep, can still remember the weird tingly cold sensation.
Anyway, that might be a good extra example to have up your sleeve.
Also works for guitar players!
I have no idea what meths is but now I am imagining you rubbing crystal meth all over your hands
It’s UK for isopropyl (rubbing alcohol).
In NZ it’s short for Methylated Spirits. Probably UK as well?
Oops! I thought they were the same thing, but it looks like they’re just used for overlapping purposes.
Ha! “I’m addicted to meth now, but my nails look GREAT!”
You don’t actually notice when it dries! Basically the manicurist will just paint it on your nails as you do with regular nail polish, then instructs you to slide your hand under the UV light thing, which is kind of just a box in a half circle shape with a little tray your hands rest on. And then your hand is kind of warm for 30 seconds, not uncomfortably so, and then it’s all dry! Because it’s such a fast process you don’t feel anything except the warmth of the light.
That’s fascinating! From the description in the piece it sounds like “dry” isn’t even really the right way of thinking about it – it doesn’t actually lose any moisture, instead it changes from substance to another while on your fingernail. Very cool.
(Wait, but how do you get it off, then? Have you gotten to that part yet? Can you just peel it off, like a fruit rollup?) (Do they still have fruit rollups?)
REMOVING THEM IS ALSO SUPER COOL
I’ve gotten two gel manicures – the most recent time I just peeled them off myself after about two weeks because it wasn’t a great polish job and the polish was starting to bubble up around the edges so I could just grab a corner and tug, and it comes off in one thick strip. The first time, though, I had the polish on FOR A MONTH without it ever chipping because the manicurist was amazing, and I had to go in to get it removed, which costs about $5 and involves the manicurist soaking a cotton ball in acetone and smushing it to each of your fingers with aluminium foil, so you have pointy aluminium foil fingers for 20 minutes while you watch Blue Jasmine on the nail salon’s TV.
I don’t know why it takes so long for the acetone to sink in and dissolve the polish? Anyone? Science?
I’m not sure, but this is the trick I’ve always used to remove particularly stubborn glitter polishes!
Ooh, thank you! There’s always that one last damn sparkle that won’t give up its perch on my toe. Now I’m going to roll them into acetone burritos and git ‘er done right.
Would applying it in direct sunlight have the same effect?
I’ve had gel manicures and I feel like they’re more secure on my nails- they cling or apply pressure in a way that regular nail polish doesn’t. It’s the same effect for me as using a fast-dry topcoat. I wonder if the chemical makeup is similar?
Me too! My mind is blown!!
This was SUPER FASCINATING and I love having this new knowledge about something I put on my body on the regular! Also, interesting note about the chemical smell – I’ve never thought about it before, but I was always more wary of nail polish because of that smell, whereas I assume, perfumes/any other scented cosmetic, are just as ‘chemically’ 🙂
WHY do I ever consider any part of modern life mundane when honestly it is all made of science fiction and explosions and maybe also witchcraft? I mean, not witchcraft, but “Pearl essence shines like the beautiful silvery iridescence of fish scales because it is made out of ground up beautiful iridescent fish scales” sure sounds like alchemy to me.
Thank you SCIENCE for letting us play nimbly with chemicals and their properties, while, theoretically, laughing heartily.
and occasionally laughing heartily in earnest
tricksy SCIENCE with its theoretical laughter
And they went to the Rainbow Fish and said “hey, we want to grind up your beautiful scales into nail polish,” and the Rainbow Fish was all “um… I’m not sure how I feel about that” and they said “YOU FEEL SELFISH THAT’S WHAT” so the Rainbow Fish said “all right, fine.”
And that’s why nail polish is all the colors of the rainbow.
Can we talk about what happens when you apply a fast-dry topcoat to regular polish? Fascinating!
Yes! I’ve always wanted to know how that works! (Or doesn’t work, sometimes with horrible consequences…)
I’ve tried a lot of duds but recently got the “Seche Vite” brand and DAMN, does it work. But it feels like I’m pouring cement over my nails, which can’t be good. They need to breathe, right? Be exposed to air? Or is that a misconception?
The body is a mystery.
The thing I hate about Seche Vite is that the formula is so think, it evaporates super quickly and after a month I have a lot of useless gummy polish in bottle, because I’m never going to use it all up in a month. I sometimes buy the tiny sample sizes at Sally’s Beauty, but even those I don’t use up quickly enough.
They sell a thinning solution for this issue, so you can just put a couple drops in the thick goopy Seche Vite bottle and it works normally again, but goddamn am I going to spent $15 on one tiny bottle of topcoat. I found an OPI fast-drying topcoat I like way better anyway. Also! Apparently Seche Vite shrinks the layer of polish underneath? I’ve never noticed this but apparently the coloured nail polish will contract and shrink after you apply Seche Vite, so it looks like you didn’t quite paint the whole nail.
I just recently tried seche vite too. Amazing results, but the toulene in it makes it pretty toxic. After using it in a closed room I had a headache and felt exhausted, which apparently a dose of toulene can do. Now I only use it in well ventilated areas.
STRAIGHT-UP FORMALDEHYDE ON MY NAILS
I have always wanted to embalm something….
Anecdote: a friend of mine bought the Essie one once and while we were waiting in the gas line during Hurricane Sandy we both had enough time to paint our nails and throw the quick-dry topcoat on before we were able to get gas.
IT WAS SO COOL.
Thank you for this! I’ve always wondered how the magic of gel nail polish worked! (And by “always,” I mean “since I got my first gel manicure in June.”)
I FUCKING LOVE CHEMISTRY.
ME TOO
My favorite part of any science class was getting to draw the molecular structures (or in the case of plant biology, how to draw cell structures), the more complex the better. Molecules! Atoms! It’s all so pretty! I just love seeing what stuff is made of, and how it’s made or used.
Totally. I’ve started taking pre-requisite orgo classes and drawing all the rings and structures and wedges and dashes and making sure everything has the proper geometry is so damn satisfying. Coming from an art/graphic background, it’s a fun cross-over.
fair-skinned redhead checking in here to wring her tragically unpainted hands about UV and whatnot
Same here. One time, a salon had me dry my regularly-painted nails under a UV light, and I was like, “I’m going to need some sunscreen before I even go near that thing.”
yeah me too 🙁
Bone cement, eh? So, that means it should be possible to turn your fingernails into giant bone claws for destroying your enemies?
aaaagh, sorry, I’m doing it again. I just have a hard time thinking about science in terms other than cartoon supervillainy.
why would you apologize for that? Focus is important!
“This makes worrying about the safety of chemicals seem more feminine, perhaps a bit irrational, and definitely unscientific…. What’s unscientific about wanting to know how things work and how they’re made?”
THANK YOU THANK YOU THANK YOU.
Please also share male tear cheese recipe.
Yes! re male tear cheese. I feel like you really buried the lede there.
Yeah, I need to hear the heroic tale of the male tear cheese.
Here is the some info on the tear cheese story for those who are interested: http://www.dezeen.com/2013/11/20/olafur-eliasson-…
OMG you weren’t even close to kidding. I’m simultaneously grossed out and fascinated! Well done, you!
Can I just compliment whoever posted this with their choice of break before the jump? I was all, ugh, science (you know, just having a flashback to high school, not because I hate actual science), but then EXPLODING COTTON AND FISH SCALES happened, and you’d better believe I was going to click. And now my mind, she is blown. And I just chipped my polish this morning, so I’m going to be painting them tonight and singing a little ditty about molecules while I do it.
thank u that was me
Yay! I’ve gotten a few gel manicures and now that I know a little more about they work I am further fascinated. And I learned someone new last time that I will share. When I mentioned I’d gone ahead and peeled one off because they were starting to pull away, my manicurist tells me “oh, well if you want to keep them longer and they do that, throw some clear regular nail polish on. You can also put any kind of regular nail polish over your gels if you want a lighter color or you get bored, then wipe it off with regular nail polish remover, if you want.” I didn’t ever think to do any of this. Maybe everyone knew this, but I didn’t!
Yeah man! Back when I was getting gel manicures on the reg (because I found I had to keep doing it once I started) I would get light colours and then paint over them with dark colours and change them up. The regular nail polish would not chip much because of the hard base.
Now I’m frugal and also kind of over performative femininity (at least some forms) so I have just regular person nails.
This is my favorite Gal Science yet.
Okay, so what is up with these “UV-free gel polishes” I’m seeing in the drugstore now? (Yes, this where I get my beauty learnings. Low-budget femme, c’est moi.) Does not compute!
ooh good question! It looks like they come with an “activator” that you paint on first, and then the gel polish that you paint on while the activator is still wet. maybe there’s one chemical in the activator and another in the polish, and when you combine them together, they make a really sensitive photoinitiator?
I mean, there’s some uv light just, always around, you know? so maybe the chemical is sensitive enough that it just needs ambient light to start the chemical reaction that hardens your nails, but because it’s so sensitive, they can’t just ship it as a finished product, because it would all just harden in transit, so they separate it into two parts that you just combine on top of your nail?
this is the most interested in nail polish I have ever been!
This is what I want to know. I’ve been assuming it’s like how they just slap the word greek on some slightly thicker yogurt and just go with it.
Love this!
I didn’t know exactly how the uv was setting the polish and now I’m super happy to get it.
What about shellac?
They say in the nail place that gel and shellac are different but I don’t quite believe it. Is there any science there that you can share?
So what I’m hearing is, these chemicals (nitrocellulose, methyl acetate, benzoyl peroxide, methyl acrylate) “doesn’t pose much more of a threat to your safety.” Really? What about inhaling these chemicals while putting on or removing polish? What about the UV lights that set the gel polish? Shouldn’t “science” have something to say about the safety of chemical exposure?
I literally said, "That is so cool!" five different times while I was reading this.
Nitrocellulose? Isn’t that what old time film stock was made from? You know the stuff it explodes easily.
Nitrocellulose? Isn't that what old time film stock was made from? You know the stuff it explodes easily.
Okay, but can I still get mad about advertisers using the general public’s perceived lack of knowledge about science and chemicals to scare them into certain purchasing decisions? Cause that’s SO ANNOYINGLY PATRONIZING. (YOU’RE a sodium diacetate!)
But for serious, gel polish is fantastic. Even if I turned my fingers blue and totally jacked up my nails trying to get it off at home…
Science has quite a lot to say about it. Googling finds studies showing that if you work in a nail bar or a factory producing nail varnishes, there may be a small risk to pregnant women, for example. So if you’re working somewhere where you’d be exposed to those kind of chemicals in large quantities, it’s really important that there is legislation to protect you from losing your job and being forced to stay in that environment. The risk to anyone just putting on nail varnish at home every few days or every couple of weeks is going to be absolutely minimal, though.
I don’t know, why would you assume Science doesn’t look at the safety of household and cosmetic chemicals? They’re pretty tightly regulated in North America and the EU, and where there are scandals it’s nearly always more likely to affect workers who are experiencing high levels of exposure rather than consumers who experience much lower rates of exposure. And that’s much more of a capitalism and labour rights issue than a science issue.
i am so reassured i am not the only person whose mind flashed to polymerization reactions while her fingers were held captive under a UV light.
also, this was so excellent. just – so much fun to read.
I love Acquarella’s less toxic, water based nail lacquers for my toes! Wears like iron, doesn’t make my nails peel, and no nasty smells. Bit of a learning curve to get it on but
Between this and a recent article in Mosaic on how hair dye is NOT just “paint for hair”, I now feel totally up on my Chemistry of Feminine Arts. Wait… can this be a new subject?
Between this and a recent article in Mosaic on how hair dye is NOT just "paint for hair", I now feel totally up on my Chemistry of Feminine Arts. Wait… can this be a new subject?
This is a pretty late reply, but I just wanted to confirm. The answer is yes. How do I know?
…I may or may not have turned my own nails into bone claws on the regular.