Hi it's me Michelle from Lab Muffin Beauty Science. I'm a chemistry PhD
graduate who loves skincare science, and today I'm going to be telling you about
how miceller water works. Micellar water is a type of cleanser that's super
popular with makeup artists and beauty addicts. The most famous micellar water
is probably Bioderma Sensibio H2O. Apparently one bottle of this is sold
every five seconds worldwide. A quick chemistry side note: it's H2O,
as in the letter O, not the number zero. This is a pet peeve of mine as a chemist
because H2O is the molecular formula for water. What this means is
that there are 2 hydrogen atoms bonded to 1 oxygen atom. So we have two
Hs and one O. H20 would mean that there are 20 hydrogens bonded together,
which just doesn't happen, except maybe once in a star, somewhere. Anyway, back to
micellar water! Micellar waters are cleansers that you pour into a cotton
pad, then wipe over your skin. You don't need to rinse them after you use them, so
it's almost like makeup wipe liquid in a bottle. How do they work? We're going to
have to talk about the physical chemistry of surfactants to understand
what's going on. The key ingredients in micellar water are a surfactant or
multiple surfactants, and water. Oil and water usually repel each other and oil
won't dissolve in water or vice versa, which is why you can't wash an oily dish
with plain water. This is because oil is non-polar and water is polar.
It's like oil is velcro but water is a magnet: they just don't work together.
This is a chemical principle that's commonly known as "like dissolves like",
which means that oil and water don't form sticky interactions with each other.
But if you add surfactants to the mix, that's a different story.
Surfactants are nifty little molecules that have two halves: a hydrophilic head
that's attracted to water and repels oil, and a hydrophobic or lipophilic half
that's attracted to oils and grease and repels water.
It's like you've sticky taped a magnet to velcro. Now everything can stick
together in a big happy heap. In chemistry this happy mixture is called
an emulsion. Because getting oil and water to hang out together happily is
really handy, you'll find surfactants in lots of products: soaps, shampoos,
dishwashing detergent, laundry powders, moisturisers, foundations, mayonnaise, milk,
ice cream, and of course, micellar water. For example with an oily dish, the
surfactants in the detergent can sink into the oil. Then when you scrub the
dish, the surfactants break up the oil into droplets. Since the surfactants hang
out at the surface between oil and water, they sort of hide the oil from the water.
It's like it smuggles the oil into the water so you can wash it away. It's the
same idea with mayonnaise. Oil and vinegar usually don't mix, but if you
have lecithin from egg yolk as an emulsifier or surfactant, it can smuggle
in droplets of oil into the vinegar, and they stay together as a thick creamy
delicious goop. When you use micellar water, you pour the product onto a cotton
pad. Cotton is made of cellulose which is polar,
so the hydrophilic heads are going to stick to the cotton like magnets and the
hydrophobic tails are going to stick out on the surface of the pad like velcro.
And guess what? Make up and oils and grease are non-polar, so they're like
velcro as well. So when you wipe the pad over your skin, the tails will grab the
makeup and oils and grease so you end up with clean skin. You might be wondering
when I'm going to start talking about micelles. Micelles aren't actually that
important to how micellar water works. When you add a surfactant to water,
like if you mix dishwashing detergent with tap water, we have the hydrophilic
heads and the hydrophobic tails of the surfactants and a bunch of water. Since
the hydrophobic tails don't like water and the hydrophilic heads do, the
surfactant molecules are going to arrange themselves or self-assemble so
the tails aren't touching the water. They can do this in two ways. The tails
can stick out of the water into the air at the surface, sort of like ostriches
burying their heads into the sand. Or they can arrange themselves into little
balls with the heads at the surface and the tails on the inside, sort of like
tiny pin cushions. These little balls are called micelles. Any surfactant in water
will form micelles. The main difference with micellar water is that it's
formulated so that the surfactants aren't as damaging to your skin as a
standard rinse off cleanser. Unfortunately since surfactants are sticky
they tend to stick to things in your skin such as proteins, which changes
the structure of your skin. Since your skin's main role is to act as a barrier
to keep water in and unwanted germs and chemicals out, this means that you can
end up with a leaky barrier. Micellar waters are made so that the surfactants
won't do this as much as a standard rinse off cleanser. For example they tend
to contain gentler surfactants than a regular cleanser. They're also sometimes
formulated with moisturizing ingredients like fatty acid esters to keep the skin
barrier intact. But for some people who have sensitive skin, even micellar water
might be too much. So if you find that your skin is dry or itchy or tight after
you use micellar water, you can try wiping it off or rinsing it off with a
wet towel or just water. So that's how micellar water works! I hope you found this
video useful. If you liked it please subscribe to my channel, check out my
blog, follow me on Instagram, send me cake, send me science memes and I'll see you
next time for more beauty science :)