Humans have always been interested in modifying the appearance of their hair. Among the varied methods of hair styling, one notable method is the “perm,” a permanent styling achieved through alteration of the hair’s chemical structure. In the 20th century, technological advancements made the perm possible, although early methods using heating devices damaged hair because of excessive heat. However, in the 1940s, the cold wave (which could produce waves in hair without damaging it) was introduced.
It alters the hair’s disulfide bonds, which are responsible for waving (although, additionally, the hair’s moisture content also has an effect on the physical properties of hair). Hair perming has two phases: physical (where the hair is wrapped in curlers or rods) and chemical (where chemicals break down and reform the hair’s disulfide bonds). A person who gets a perm treatment is usually advised to avoid shampooing for a day or more and to apply hair conditioner to avoid damaging the hair. Introduction
Throughout history, women and men alike have been doing things to change the styles, textures, and wave patterns of their hair in order to enhance their appearance. Different kinds of hair modification processes and hair treatments have been devised for this purpose, and one of the most famous treatments still used in modern times is the permanent hair wave treatment or simply the “perm” treatment. The curls created from a perm treatment results from the alteration of the hair’s chemical structure and these curls cannot be un-done unless though other chemical treatments.
People have been looking for ways to make curls or waves “permanent”, thus the popularity of this method. History of the Perm The perm can trace its roots in Ancient Egypt, where women fashion curls on their hair by using a mixture of soil and water, rolling them using primitive curlers, and then baking them in the sun in order to apply heat. This same principle was subsequently used in later times, wherein waves are created by setting damp or treated hair on curlers, then applying heat to make the curls hold. This method however, does not produce permanent results.
By the dawn of the 20th century, technical and scientific innovations made permanent waves possible. One such invention is the “Nestle Permanent Hair Wave,” a contraption created by Charles Nessler. It makes use of electricity (instead of the sun) to apply heat to the hair, and it activates the “waving lotion” used to produce curls. This machine was first publicly displayed in October 8, 1906, and was widely available in the market by the 1920s. During that time however, heating devices do not have thermostats (meaning, the amount of heat is not regulated), so perm treatments can result in dry, fizzy, and unmanageable hair.
In the 1940s, the cold wave was introduced and became the precursor to the modern perming process, as we know it today. The first permanent cold wave was done using the combined action of thioglycolic acid with hydrogen peroxide. In this process, the amount of heat can also easily be adjusted so hair can be curled closer to the scalp. Hair Structure and Chemistry The main constituent of hair is a protein called keratin, which contains long chains of amino acids, and carbons bearing oxygen atoms. Keratin, in particular, contains a large amount of the amino acid, cystine, which can form disulfide bonds between protein chains.
Keratin develops in the follicle, an indentation deep down in the layers of the skin. Each hair strand has a cortex in its center. This cortex is made up of microfibers, which are held together by four types of bonds: hydrogen bonds, ionic/salt bonds, cystine bonds, and polypeptide bonds, which give hair its strength and form. Surrounding the cortex is the medulla, which is where side bonds (that give hair the “wave” pattern) are found. Water is also an important element it determining the hair’s physical and chemical properties and makes up about 10-13% of its composition. The Process: How Perming is Done
The perming process involves two parts: the physical phase (which involves the wrapping hair in molds) and the chemical phase. The modern method of perming hair involves chemicals that break and reform disulfide bonds (which dictate the hair’s shape). Hair perms can be created by using either acidic or alkaline solutions. Since different types of hair have different pH levels, the effectiveness of the perm will depend on the type of solution used. Alkaline perms are best for coarse, resistant, and inelastic hair, while acid perms (which are milder) are best for delicate or damaged hair.
Hair is washed first, and then wrapped around a curler or rod. A perming lotion, which reacts with the keratin in the cortex, is then applied. The solution in the lotion softens the hair by breaking the disulfide bonds and cross-links within and between protein chains. Heat can be applied to help loosen the hair for acid perms, but alkaline perms can be used at room temperature. Hair will then swell, soften, and stretch to take the form of the molds or curlers. After treatment, the perming lotion is washed off and a neutralizing solution is applied.
The neutralizing solution is the one that re-forms the disulfide bonds so that the curls will set and become permanent. Those who have undergone a perm treatment are usually advised to eschew shampooing for a while, since shampoo may interrupt the “curing“ process. However, it can sometimes be advisable to use a conditioner, since newly-permed hair can be prone to damage. What Happens to Hair During Perming Side bonds in the hair’s medulla are made up of three bonds: hydrogen bonds, ionic/salt bonds, and disulfide bonds.
Disulfide bonds are what makes hair hold its shape, and are composed of bonds between two sulfur atoms. This bond is what gets altered in a perm treatment. Knowledge of these bonds is useful in understanding the process of hair perming. What happens during perming is that the disulfide bonds are broken by a reducing agent (the perming solution). The principle is that when these bonds are broken, they can shift positions in relation to each other and will readily take on the shape of the mold (usually curlers or perming rods).
An oxidizing agent (the “neutralizer”) is then applied so that the disulfide bonds will reform in their new positions, and this will permanently change the shape of the hair. Typical reducing agents include ammonium hydroxide and ammonium thioglycolate, while the most commonly used reducing agent is hydrogen peroxide.
References
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