CJAMY. Camille Goubert’s column is broadcast daily on the program “Cijami”, which is presented on France 5 from Monday to Friday at 5 pm.
When it rains or when you get out of the shower, hair that is not straight and long knows that their hair has wavy and even curls. This effect of water on hair is explained by the structure of hair, in which water is able to penetrate to increase its length and – temporarily – modify its structure.
Water seeps under the hair scales
Hair absorbs an average of 30% of its weight in water. A real sponge! This is because if their nature lends itself, they start curling when it rains. To understand, you need to know that the hair is a bit stiff: it is a tube. Except that, instead of the insect, we find the marrow, a type of tunnel with very loose cells. The outer part of the hair, the cuticle, is a scale-like protection that protects the hair. And in the middle is the cortex, which is made of keratin fibers. It is this that gives the hair their elasticity and strength. And this is where water comes in to accomplish its task: because when it infiltrates under the cuticle scales, it disrupts the chemical bonds, and more accurately the hydrogen bonds, between the keratin fibers.
Wet hair can stretch 30% of its length
Hydrogen atoms in keratin prefer to bind to water rather than bond with each other. The hair is filled with water, it is swollen, it is relaxed and can stretch 30% of its length. It is this reorganization of keratin that causes wet hair to change shape. Depending on its basic nature, it is curled or frizzy. Once dried, the hair recovers its hydrogen bonds and does not proceed except to heat them… or repeat them again.
Hair has so much ability to absorb liquid that in the summer of 2020 Mauritius residents and hairdressers donated hair to spread the oil. Because once assembled in sausages inside simple tights, up to 3 kg of oil can be absorbed by the hair.