The hair care products that are part of our daily routines, from shampoos and conditioners to styling aids, are significantly enhanced by the inclusion of polymers. These polymers play a pivotal role in improving the effectiveness of these products, offering a range of benefits that help us achieve our desired hair outcomes.
Polymers are large molecules composed of many smaller molecular units known as monomers, which are chemically bonded together. Think of a polymer as a chain, with each link in the chain representing a monomer. This chemical structure allows polymers to exhibit diverse properties and functionalities in hair care formulations, such as improving texture, providing hold, and conditioning the hair.
In this discussion, we will explore the various types of polymers commonly used in hair care products, examining their specific roles and how they contribute to better hair quality. To ensure the information presented is both accurate and comprehensive, I’ve consulted a hair scientist and cosmetic formulator with a PhD in Chemistry. His expertise offers invaluable insights into the science behind polymers in hair care, helping us understand why these ingredients are so beneficial in our favorite products.
What are Polymers?
The word polymer is a combination of “Poly” and “mer” where poly means many, and mer stands for units.
A polymer is a large molecule formed by the chemical bonding of several smaller molecular units. The small repeating units are called monomers (a single unit). So, the polymer is a chemical compound formed by the bonding of several monomers.
Polymer science has greatly impacted our modern world, with polymers incorporated into almost all aspects of life. Intriguingly, the science behind polymers was inspired by Mother Nature herself.
From a vast range of naturally occurring polymers that are used in many different applications, Mother Nature has gifted us with natural polymers.
For example, starch is a polymer formed by repeating units of sugar molecules. Protein is also a polymer formed by combining several amino acids.
Plastic is a synthetic polymer and today is almost everywhere. Cellulose is another example of a natural polymer present in wood and plant bodies.
By studying natural polymers, scientists have been able to make amazing advancements in the development of synthetic polymers that can be used for a wide range of applications in our daily lives.
Polymers are regularly used in cosmetics, skincare, and hair care products to help improve the overall product aesthetics as well as its stability.
Furthermore, they help form a protective film over skin or hair surfaces. In particular, for items designed for use on hair such as shampoo and conditioner, polymers can add strength to hair fibers while also improving its health and sensorial feel.1, 2-3
Now, let’s get into the fundamentals of polymer science as it would help us understand the logic of using polymeric ingredients in a formulation.
Polymers and Polymerization
A polymer is a large chemical molecule formed by the chemical bonding of monomer molecules. The polymer has a large molecular structure and higher molecular weight.
The chemical reaction carrying out this process is called polymerization. The chemical illustration below describes a simplified chemical reaction involving monomers reacting to form a large polymer.
Amino acids are biological chemical compounds that combine to form a large polymer called protein.
The small fragments of amino acid polymers are called peptides, whereas several of them combine and form a protein called a polypeptide – highlighting the importance of polymers in our bodies. Hair is a polymeric structure composed of keratin protein, created in the same manner.
Several amino acids combine in a genetically coded pattern to form double strands of keratin structure.
Two amino acid molecules react to form a dipeptide (dimer – two units) which goes on to combine other amino acids forming a large protein structure.
A perfect illustration of synthetic polymeric chemistry is found in PVC plastic. PVC is polyvinyl chloride, which is a plastic used to manufacture plastic goods including sanitary and water pipes.
It is prepared by the polymerization of vinyl chloride combined to form a large polyvinyl-chloride (PVC).
To summarize, the distinctive characteristics of polymers are as follows:
● Polymers are large molecules with higher molecular weights.
● Monomers combine to form a polymer.
● The fascinating fact is, the chemical and physical properties of a polymer might be very different from the chemical and physical properties of its smaller building blocks (monomers).
Why Do We Have Polymers in Hair Care Products?
Benefits of Hair Fiber
Polymers are multifunctional ingredients that can be used to address nearly any hair science need. There is a wide range of polymers available on the market today for all sorts of applications.4,5
Polymers deliver several benefits to hair care products:
● Hair conditioning
● Detangling
● Restores the mechanical strength of hair fiber, making it stronger.
● Slip and improved wet and dry combing of hair.
● Superior sensorial feel on wet and dry hair.
● Hair fixing or style retention.
● Film forming over the surface of the hair shaft to alter its cosmetic properties and aesthetic response.
● Improves the stability of the product, especially in an oil-in-water or water-in-oil emulsion.
● Boosting the product viscosity.
When selecting a polymer for a certain formulation, the desired result should be taken into account. Additionally, it is essential to consider the chemical properties associated with that specific class of polymer to achieve the most accurate outcome.
For example, incorporating thickening polymer can significantly increase the product’s viscosity and provide a desirable gelling effect.
Types of Polymers used in Hair Care Products
Below, polymers are divided according to their functionalities and the roles they play in a formulation.
Natural Polymers or Gums for Aesthetic and Viscosity
Hair care products often take advantage of plant-extracted gums to enhance the viscosity of the formulation, improve the sensorial aesthetic of the product, and deliver ease of application.
Xanthan gum is particularly popular among them. It is a natural polysaccharide polymer where several different sugar molecules are bonded to form a long polymeric chain.
Guar gum is another natural thickening polymer extracted from guar beans. It is also a large polymer containing multiple polysaccharides units.
Cationic Conditioning Polymer
Cationic polymers are perhaps the most often and abundantly used polymer in hair care formulations. Cationic means the polymer carries a positively charged group attached to the polymer backbone.
The polymer structure is designed with a large hydrophobic chain attached to a quaternary nitrogen group carrying a positive charge.
Featuring a positive charge, cationic polymers bind to the keratin protein of hair by an electrostatic chemical bond due to its opposing negative charges.
The quaternary nitrogen group attaches these polymers to the strand’s surface while its long hydrophobic chain adds conditioning and detangling benefits to hair. This electrostatic chemical bonding is responsible for hair conditioning.6,7
Haircare products commonly include a variety of ingredients, which we explore below.
● Guar Hydroxypropyltrimonium Chloride (GHPTC): GHPTC is a guar gum-modified cationic conditioning polymer that attaches itself to keratin proteins and acts as an effective agent for hair conditioners. It is commonly added in conditioning shampoos formulated for damaged, porous, and fragile hairs. It also facilitates the deposition of emollients, natural oils, and anti-dandruff active ingredients.
● Polyquaternium(s): Polyquaternium is the internationally accepted naming system for cationic polymers, which are also known as synthetic cationic polymers. Formulators now have access to an array of polymers, also called “polyquats” in scientific literature, frequently utilized within hair care products.
● Polyquaternium – 10: It is a cationic cellulose-derived conditioning polymer that is also commonly used in conditioning shampoos, conditioners, and treatment masks. It is a relatively heavy polymer with a higher positive charge density, which makes it an ideal ingredient for excessively damaged and fragile hair fibers (chemically treated, color treated, bleached, UV damaged, and African-American Hair). Its benefits include detangling hair, making it easy to comb (whether wet or dry), and improving mechanical strength.
● Polyquaternium – 6: Due to its positive charge density on its nitrogen group, it demonstrates a higher deposition in chemically treated hair. It provides deep conditioning, restores the mechanical strength of already compromised damaged hair fiber, and improves its cosmetic features. It is normally used in hair conditioners and treatment masks.
● Polyquaternium – 7: This is compatible with anionic surfactants and is often used in hair shampoos. It has a large molecular structure and weight and forms a film over the hair shaft. This coating improves the surface properties of the hair shaft, addresses cuticular damage, and provides a slip to the surface. This improves combability and manageability. Its large molecule size and weight allow it to form a protective film over the hair shaft. This coating improves the surface properties of your hair, addresses cuticular damage, and provides slip to the hair surface. As a result, you will experience improved manageability of your strands.
Other common examples of polyquaternium series are:
-Polyquaternium – 5
-Polyquaternium – 22
-Polyquaternium – 28
-Polyquaternium – 37
-Polyquaternium – 39
-Polyquaternium – 47
-Polyquaternium – 53
-And many more
Styling Polymers
Hair styling products have been formulated to shape hair into desired styles and maintain them, even in the presence of varying humidity and temperature levels.
Almost all styling products contain styling polymers. Styling polymers create a protective barrier around the hair, safeguarding it from extreme humidity and low-temperature conditions. These film-forming polymers coat each strand of hair to preserve its inner protein structure.
These polymers dry rapidly and provide a glossy appearance on the hair shaft. This quick drying ensures film becomes firm quickly and gives a definite style to hair fibers.5
Polyvinylpyrrolidone (PVP) is an early adopter of the popular hair-styling polymers. While it offers outstanding hold and lasting style retention, its film falls apart once dried, resulting in unwanted flaking. Furthermore, under humid conditions, it suffers from poor styling performance.
The latest advancement in hair science has created a new generation of styling polymers, providing better style retention even when the humidity is high and without any unpleasant flaking.
Other styling polymers are:
- PVP/VA (a modified version of PVP)
- Polyquaternium-55 (a cationic hair styling polymer with superior hold and humidity resistance)
- Polyquaternium – 69
Viscosity Boosting Polymers
Every product must possess a suitable viscosity for it to be used effectively and remain stable during storage. If not, results may be unsatisfactory or the entire product could become compromised over time.
Viscosity-boosting polymers are used in hair shampoos, creams, and styling formulations. When selecting a polymer, there are various factors to consider such as the product type, desired viscosity level, and its compatibility with other ingredients.
One good example is carbomer. It is an anionic gelling polymer that is widely used in hair creams, pomades, and styling products.
Nearly every hair gel is crafted with carbomer as its main ingredient, which increases in viscosity upon neutralization by an alkaline agent.
The optimum pH for the highest viscosity is 6.60 – 7.10. Over the years, new versions of carbomer have emerged that are better equipped to coexist with other ingredients while also producing a greater increase in viscosity.
The examples are:
- Acrylates/C10-30 Alkyl Acrylate Crosspolymer
- Emulsion Stabilizing Polymers
Polymers are also used as co-emulsifiers facilitating the emulsification of oils and enhancing the stability of the emulsion system.
An emulsion is a white creamy formulation made by mixing oil with water. Oil normally does not dissolve or mix with water. It stays on top, however, adding a small amount of an emulsifying agent can disperse oil droplets into water. This is called emulsion and generally appears white.
Hair conditioners, creams, and pomades are all emulsions. To create a stable emulsion, polymeric emulsifying agents can do the job proficiently with lower dosage concentrations compared to traditional emulsifying agents.
Polymers not only help to reduce oil droplet size in water and decrease the water surface tension but also act as a catalyst for greater emulsification that helps maintain product stability.
Some examples in hair care are:
- Acrylates/Beheneth-25 Methacrylate Copolymer
- Polymer TR-1 & TR-2
- Silicone Polymers
Silicone polymers are strongly hydrophobic and water-insoluble. They contain a silicone functional unit bonded to either oxygen or a methyl group in a repeated pattern to form a large silicone polymer.
These silicone oils are regularly used in hair care formulations to provide slip, detangling, shine, and protection against thermal treatments.
Thanks to their hydrophobic properties, these coatings repel water from hair shafts and provide essential protection against heat damage caused by blow drying and flat ironing.8,9
Dimethicone is a common example. It is a viscous transparent liquid that provides slip, shine, detangling, and thermal protection.
Other silicone oils are:
- Cyclomethicone
- Pentasiloxane
Silicone oils are notoriously difficult to remove when you shampoo your hair, as they don’t dissolve easily in a standard washing product. The resulting build-up can weigh down the hair and make it appear limp and lifeless, robbing it of its natural body.
Polymeric Build-up Can Be a Concern – Here’s What You Need to Know
The long-term use of products that contain polymers can cause a build-up over the hair, resulting in undesirable effects.
Your hair may lose its natural look and body, as well as become dull; ultimately making it appear lackluster. Make sure to switch up your routine with non-polymer-containing products to keep your locks looking their best! Make sure to use “Anti-Residue” or “Clarifying” Shampoo to get rid of the polymeric build-up.
Summary
When it comes to hair care formulations, polymers are the popular choice. Not only do they stabilize and detangle strands, but they also offer a boost in mechanical strength as well as make styling effortless. Plus, your everyday grooming will be easier than ever!
Scientific reports have evaluated their efficacy and have found them effective in controlling hair damage and boosting overall hair quality.
Today, polymers have become essential elements of the majority of hair care products. It is truly remarkable to note the tremendous effect that these incredible molecules are having on hair care research and development.
References
1. Schueller, R.; Romanowski, P., Conditioning Agents for Hair and Skin. Taylor & Francis: 1999.
2. Lochhead Robert, Y., The Role of Polymers in Cosmetics: Recent Trends. In Cosmetic Nanotechnology, American Chemical Society: 2007; Vol. 961, pp 3-56.
3. Lochhead, R. Y., The role of polymers in cosmetics: recent trends. 2007.
4. Hössel; Dieing; Nörenberg; Pfau; Sander, Conditioning polymers in today’s shampoo formulations – efficacy, mechanism, and test methods. Inter. J. of Cosmet. Sci 2000, 22 (1), 1-10.
5. Zviak, C., The Science of Hair Care. Taylor & Francis: 1986.
6. Pfau, A.; Hössel, P.; Vogt, S.; Sander, R.; Schrepp, W., The interaction of cationic polymers with human hair. Macromolecular Symposia 1998, 126 (1), 241-252.
7. Syed, A. N.; Habib, W. W.; Kuhajda, A. M., Water-soluble polymers in hair care – Prevention and repair of damage during hair relaxing. In Water Soluble Polymers: Solution Properties and Applications, Amjad, Z., Ed. Plenum Press Div Plenum Publishing Corp: New York, 1998; pp 231-244.
8. Yahagi, K., Silicones as conditioning agents in shampoos. J. Soc. Cosmet. Chem. 1992, 43 (5), 275-284.
9. Rojas Wahl Roy, U.; Nicholson, J. R.; Kerschner Judith, L., Silicones in Personal Care Applications. In Cosmetic Nanotechnology, American Chemical Society: 2007; Vol. 961, pp 177-189.
