Today’s Video of the Day from the American Chemical Society series Reactions describes the chemistry of artificial hair color.
In ancient times, people colored their hair using vinegar, nutshells, berries, and lead. By 1907, French chemist Eugene Schueller had developed a hair color formula that used paraphenylenediamine (PPD), a compound that is still used in some dyes today.
The hair shaft is protected by a layer of keratin cells called the cuticle. Non-permanent dyes coat the cuticle but then fade quickly, while permanent dyes penetrate the cuticle to reach the inner layer of the hair’s shaft known as the cortex.
By Chrissy Sexton, Earth.com Staff Writer
Video Credit: American Chemical Society