Having had over 50 manicures in my life, i decided it was time to do a little research into the science behind these little bottles of magic.
Good-ol Nail varnish
Here’s a list of basic ingredients for a typical nail polish, and what they do:
Nitrocellulose – forms a shiny&hard film (highly flammable polymer, found in gunpowder)
Adhesive polymers (resins) – provides good adhesion of nitrocellulose to nail surface
Plasticizers (eg. castor oil, stearate esters, camphor) – adds flexibility and prevents cracking&flaking
Pigments/Dyes (eg. micas, pearl essence) – adds colour
Thixotropic thickeners – recall DFD lectures: “thixotropic substances are highly viscous at rest but become more fluid when shaken”
UV filters – prevents sunlight from changing the colour of pigments
Volatile solvent (eg. butyl acetate, ethyl acetate) – evaporates, leaving behind a pretty mani. Also the cause of nail varnish’s characteristic smell. And makes my dog sneeze.
The dish on Gelish
A gelish mani involves the same steps as any other normal mani (2 coats of colour with base and top coat), with an addition of a UV/LED lamp to set the gelish (only UVA rays). The hand is placed under the light for about 2 mins, but usually it sets in seconds. Gel nail polishes are formulated with photoinitiators and resins. When exposed to the right band of UV light, polymerization occurs and the polish hardens or cures.
PROS – fast, shiny, lasts for 3weeks & odourless!
If you ever wondered what’s that last cold liquid they wipe your perfectly gelly nails with.. its ISOPROPANOL – removes the sticky uncured inhibition layer on top (gooey layer left when oxygen prevents proper curing).
If you ever attempt to apply gelish outdoors, UV light from sunlight will harden ur brush as polymerization takes place. For this reason, all gelish nail polish (even clear colourless ones) are sold in opaque bottles.
Is it safe?
When you return to the salon in 3 weeks time for a new colour, they wrap ur fingertips in acetone filled cotton and aluminium foil. Pure acetone is very drying and can make your nails brittle and peel! Unlike diluted acetone in normal varnish remover. Moisturizing may help.
Also, the surface of the nail is usually abraded/roughed with an emery board, before gel polish is applied. This supposedly enhances adhesion. However, it may weaken your nail and lead to breakage and possibly infection over time.
UVA rays can cause aging and sunspots. So far nothing is proven, at the level of emission it is said that lamps are not harmful. But… better not to indulge too much too often yaaa
Like most things in science, a mistake often ends up as the biggest discovery.
In a typical nail varnish, the solvent evaporates very slowly. If a solvent that evaporates too quickly is used, the remaining solvent tends to pool together (bringing the pigment along with it), leading to a crackled aka shattered film finish. The solvent in shatter nail polish is typically ETHANOL which evaporates way faster than other acetate solvents.
From a design flaw to the next big thing, science is awesome.
Nail expert sources:
The next time I get my nails painted, i’ll be thinking about the polymerization happening on my fingertips!