Polyquaternium or Polyquat
Polyquaternium or polyquat are cationic conditioning ingredients present in almost every single hair care product we find in the marketplace today. The words “polyquat” or “polyquaternium” is the combination of two words, “poly & quat” and “poly & quaternium.” In chemistry, poly stands for polymer; it is a chemical compound made up of multiple units bonded together, while quat or quaternium suggests a positively charged species.
Thus, all polyquats or polyquaterniums are cationic polymers carrying a net positive charge. They are also known as “quanternized polymers.” These polymers are added into hair care formulations to improve hair fiber’s overall quality due to their strong affinity for hair.
Since their introduction in the early 60s, they are almost an integral part of hair care products. Recent advancements have led to introduce new versions of these polyquats with improved results and substantivity with hairs. Despite the fact of their topmost benefits, they have come under intense scrutiny in recent times because of their synthetic nature and accumulative build-up on the hair’s surface.
The most commonly employed cationic polymers are; Guar Hydroxypropyltrimonium chloride Polyquaternium 6, 7, 10, 22, 28, 37
We have around 40 different polyquats registered today. The number mentioned in their INCI name (e.g. 6 for Polyquaternium-6) represents their order or registration sequence. In today’s short blog, I’ll touch on some basics polyquats, their interaction with hair, as well as the build-up problem associated with them.
Polyquats in a Hair Care Product: The Performers
Haircare products aim to improve the overall quality of our hairs. Hair damage is a prevalent problem among the vast majority of consumers. Everyday grooming, combing, chemical treatments, and excessive exposure to solar radiation indict significant damage to hair fibers. It loses protein content; hair becomes weak, brittle without any shine and life; thus, we need a recovery plan.
The hair surface is the most exposed and can be fiercely damaged. The outer cuticle layer becomes eroded, and the inner cortex gets exposed. Moreover, hair proteins are oxidized and get negative sites all along its hair shaft. This cause frizzes and fly away problem leading to difficulty in everyday manageability and styling. At this point, we need something that can restore the outer surface of the hair shaft, improve detangling, minimize fiber-to-fiber friction, and address frizz. Cationic ingredients are an excellent remedy for this purpose.
The Basic Chemistry of Polyquats
Polyquats or polyquaternium are cationic polymers. They are synthetic organic polymers with a large carbon chain backbone attached to positive nitrogen centers. Over the years, polymer chemists have developed a large number of such polymers with different backbone structures and varying degrees of positive nitrogen centers.
These polyquates available today differ in their molecular weight, structure, and magnitude of positive charge (nitrogen level); that’s why these polyquats have varying binding strength or substantivity to hair fibers. This also gives formulation scientists a diverse range of polymers suitable for different kinds of products.
Nature-modified polyquats are more popular among formulators. A typical example is Guar Hydroxypropyltrimonium chloride and Polyquaternium 10, both often added in rinse-off formulations (shampoo, other cleansers).
Guar gum is synthetically modified to have a quaternized nitrogen to improve its detangling and conditioning benefits compared to its parent natural guar gum. While polyquaternium 10 is cationic cellulose derived from natural cellulose ( a natural polymer extracted from wood). Both these ingredients are available in different grades, having different molecular weights and nitrogen levels. They improve hair surface properties by boosting detangling and providing ease of combing for wet and dry hairs.
So, how do these quats work in a haircare formulation?
Polyquat’s in Action
Positive charges love negatives; in other words, they are attracted to each other. Polyquat polymers carry a positive charge while hair bears negative charges at its shaft, which brings them in a coulombic interaction (the interaction between electric charges, which is electrostatic in nature), where polymer binds to the negative site at the hair surface.
Polymer nitrogen gets attached to hair while long carbon chains point at the surface, offering hydrophobic lubricity. Therefore, “hair conditioning by polyquats” is pure because of their binding to the proteins at the hair’s surface. The stronger the binding, the better the hair conditioning. However, a big challenge to this interaction is water wash-off during the rinse-off stages. The polyquats should offer a wash-off resistance to deliver long-lasting conditioning.
Cationic Build-up Problem & Remedy
A negative perception about polyquat polymers is the build-up potential at the hair shaft. This build-up is caused by repeated applications and over usage of hair care formulations containing polyquats. The overuse of products containing cationic polymers leads to weighing down or limp, heavy and greasy hairs. Increased use alters the hair surface, prevents penetration of actives and water molecules into the hair fiber, and makes hair dull. All conditioning ingredients may cause the build-up, while polymers with higher molecular weight and more positive charges have a greater tendency to cause this problem.
Interestingly, not everyone will get this build-up. The deposition of any ingredient depends upon the physical conditions of your hair. The build-up problem is more profound for chemically altered hair due to increased negative sites and depleted hair diameter.
Common Examples with Higher Build-up Potential
Polyquaternium 6 (molecular weight 150,000 units) demonstrates a higher deposition at chemically treated hair and is known to cause significant build-up, which is potentially due to higher charges present at its molecule.
Another polyquat with significant build-up is polyquaternium-7 due to its larger molecular size and higher molecular weight (1,600,000 units). That’s why it is preferred for deep conditioning treatments for extremely curly, kinky, or coily hairs.
Polyquaternium 10 has multiple grades with varying molecular weights. Its heavier versions may also cause build-up depending upon the version used. Lower molecular versions are preferred for naturally curly wavy hair, while heavier grades are used for deep conditioning products. Guar Hydropropyltrimonium Chloride is another common conditioner used in shampoos, yet it is known for its build-up because of its higher molecular weight and charge density.
A properly adjusted hair care regimen can avoid any such build-up on your hair. Primarily, avoid overuse of cationic formulations such as deep conditioning shampoo or conditioners, masks, or leave-in. Having them once or twice a week might be more than enough. You can easily figure out how much you need by carefully examining your hair with your styling regimen and feel (touch your hair).
Once in a while, wash your hair with an anti-residue shampoo to remove any build-up. Please carefully choose an anti-residue shampoo, and avoid sulfates as they are harsh and may cause further adverse results.
Should We Have Polyquat-Free Regimen?
“Never judge a book by its cover”!!
Polyquats are fantastic active and functional ingredients offering superior hair conditioning, boosting the overall hair quality. The problem of build-up must not overshadow their overall performance and efficacy. A simple rule is “excess of everything is bad,” so try to have a balance in your hair care regimen to avoid any excessive build-up.
Moreover, a formulation is a combination of several ingredients working together as a team to deliver your hair the desired results. A single product should not be singled out or canceled based on one ingredient. In other words, a single ingredient or only polyquat should not be held responsible for the build-up.
Your hair is the result of teamwork by all the components present in the formulation. It’s the formulator’s job to ensure these ingredients work synergistically to have beautiful, stylish hair.
So, don’t be concerned by polyquats in your product, as they are excellent multifunctional actives for your hair.