Chemistry of Gum
It's an old home remedy that really works: getting chewing gum out of someone's hair using peanut butter. To understand how peanut butter works on chewing gum in hair, it's important to learn what each is made of and how they react when mixed together. Gum is made up of a natural gum base, usually from trees, mixed with sugars, syrups, food coloring and flavorings. The gum base molecules will cling tightly to the proteins in the dry hair. However, the gum base is hydrophobic, or "afraid of water" in Greek. This means that the gum doesn't dissolve in water. If you attempt to wash the gum out of the hair, the water will have no effect on the gum. Interestingly, because gum is hydrophobic, you can't get gum stuck in already wet hair. Dry hair, however, becomes a sticky mess with chewing gum.
Chemistry of Peanut Butter
Peanut butter is a paste made from ground and roasted peanuts. Peanuts produce a lot of oil during the process of becoming peanut butter, and some manufacturers even add some extra peanut oil into the formula for extra creaminess and enhanced taste. In other words, peanut butter contains lots of oils and fats. These are also hydrophobic substances. When gum is stuck in dry hair, take a generous slab of peanut butter and rub it all around the chewing gum. Work it into the gummy hair as much as possible.
Peanut Butter Meets Gum
The oils in the peanut butter attract the gum base in the chewing gum. That means the hydrophobic materials in both substances find it easier to stick to each other than the proteins of the dry hair. The oils in the peanut butter get in between the hair and the gum and makes the gum stiffer and less sticky. Keep working the peanut butter around the gum and you'll soon find you can pull out big chunks of gum. Make sure the peanut butter coats all the gum surface, and keep massaging it in until all the gum has been removed. Wash hair as normal and nobody will ever be able to tell there was once chewing gum in the hair. Salad oil and mayonnaise will also work the same way with chewing gum and hair because they too are oils.