Hair Conditioners: While shampoos represent the most common type of hair product, conditioners are a close second. They are designed to improve the look and feel of hair. A hair conditioner is a hair care product that changes the texture and appearance of hair. Hair conditioner is often a viscous liquid that is applied and massaged into the hair. A hair conditioner is usually used after washing the hair with shampoo. They are allowed to stay in the hair for a short time (usually 30 seconds to a couple of minutes) and then rinsed. After being rinsed thoroughly, they make the hair easier to comb, frizz-free, soft feeling, reduce static charges, improve shine, and protect hair from future damage. Conditioners contain a variety of conditioning and moisturizing ingredients that are left behind on the hair after rinsing and affect the hair characteristics. The primary conditioning agents include quaternized surfactants (quats), cationic polymers, silicones, emollients, and humectants. Hair conditioners may contain moisturizers, oils, and sunscreen, among other ingredients. Conditioners are frequently acidic, as low pH protonates the keratin’s amino acids. The hydrogen ions give the hair a positive charge and create more hydrogen bonds among the keratin scales, giving the hair a more compact structure. Organic acids such as citric acid are usually used to maintain acidity.
Using oils for hair conditioning purposes is not a new concept. The late Victorian era saw the use of Macassar oil as a hair conditioner. From almond oil, castor oil, olive oil, mustard oil to coconut oil, and many others; oiling as a precursor to shampooing has been a traditional practice across many countries, including India. Contemporary cosmetic conditioners combine the nourishing properties of these essential oils with ingredients like silicon, humectants, and acidity regulators to nourish the hair from inside out, reconstruct damaged areas and maintain the pH level. Oils are also combined with other herbal agents to make hair nourishing packs and masks.
Mechanism of conditioning
Quats (also known as cationic surfactants) and cationic polymers remain on the hair via electrostatic interactions. These ingredients are positively charged when placed in a solution of water. They are attracted to the negatively charged, damaged protein sites on the hair. This positive/negative interaction prevents them from being removed. On hair, they coat the fibers and counteract the problem characteristics.
Some conditioning ingredients are not cationic. These do not offer the best results, but they have benefits of their own. Some anionic surfactants, which carry no electric charge, will stick to the hair in useful quantities. Unlike cationic surfactants, they can be mixed with anionic surfactants to produce conditioning shampoos. Other ingredients, like esters, oils, and polymers, are added to improve luster, add comb-ability, and assure that the conditioning ingredients stay mixed in the bottle.
Silicones and emollients rely on their hydrophobic nature to plate out on the hair. Conditioners can be emulsions composed of water and these hydrophobic materials. They also contain emulsifiers which keep the oily materials suspended in solution. However, as the product becomes more dilute when applied on hair and rinsed, the oily materials separate and remain on the hair where they can counteract hair problems.
Types of Conditioners
1. Pack conditioners are heavy and thick, with a high content of fatty surfactants that can bind to the hair structure and “glue” the hair surface scales together. These are usually applied to the hair for a longer time. The surfactants are based on long, straight aliphatic fatty acid chains similar to saturated fatty acids. Their molecules tend to crystallize easily, giving the conditioner higher viscosity, and they tend to form thicker layers on the hair surface.
2. Leave-in conditioners are thinner and have different surfactants, which add only a little material to the hair. They are based on unsaturated fatty acid chains, which are bent, not straight. This shape makes them less prone to crystallizing, making a lighter, less viscous mixture and providing a significantly thinner layer on the hair. The difference between the pack and leave-in conditioners is similar to the difference between fats and oils, the latter being less viscous. The Leave-in conditioner is designed to be used in a similar way to hair oil, preventing the tangling of hair and keeping it smooth. Its use is particularly prevalent by those with naturally curly or kinky hair. There are many variants available in the market, from the rich creamy ones to the silicon-based varieties that are light and velvety in texture.
3. Ordinary conditioners combine some aspects of the pack and leave-in conditioners. Ordinary conditioners are generally applied directly after using shampoo, and manufacturers usually produce a conditioner counterpart for different types of shampoo for this purpose.
4. Hold conditioners, based on cationic polyelectrolyte polymers, to hold the hair in the desired shape. These have a function and composition similar to diluted hair gels.
There are several types of hair conditioner ingredients, differing in composition and functionality:
- Moisturizers that hold moisture in the hair. Usually, these contain high proportions of humectants. These could also be provided by natural oils such as almond oil.
- Reconstructors, usually contain hydrolyzed protein. Their role is supposed to penetrate the hair and strengthen its structure through polymer crosslinking.
- Acidifiers, acidity regulators which maintain the conditioner’s pH at about 3.5. In contact with an acidic environment, the hair’s somewhat scaly surface tightens up, as the hydrogen bonds between the keratin molecules are strengthened.
- Detanglers, which modify the hair surface by pH as acidifiers, or by coating it with polymers, as glossers.
- Thermal protectors, usually heat-absorbing polymers, shield the hair against excessive heat, caused by, e.g., blow-drying, curling irons, or hot rollers.
- Glossers, light-reflecting chemicals which bind to the hair surface. Usually polymers, silicones, e.g., Dimethicone or Cyclomethicone.
- Oils (EFAs – essential fatty acids), which can help dry/porous hair become more soft and pliable. The scalp produces sebum and EFAs are the closest things to natural sebum.
- Surfactants – Approximately 97% of hair consists of a protein called keratin. The surface of keratin contains negatively charged amino acids. Hair conditioners, therefore, usually contain cationic surfactants, which do not wash out completely, because their hydrophilic ends strongly bind to keratin. The hydrophobic ends of the surfactant molecules then act as the new hair surface.
- Lubricants, such as fatty alcohols, panthenol, dimethicone, etc.
- Sequestrants, for better function in hard water.
- Antistatic agents
- Sunscreen, for protection against protein degradation and color loss. Currently, benzophenone-4 and Ethylhexyl methoxycinnamate are the two sunscreens most commonly used in hair products. Cinnamidopyltrimonium chloride and a few others are used to a much lesser degree. The common sunscreens used on skin are rarely used for hair products due to their texture and weight effects. Table.1 gives a prototype formula for conditioning preparation with suggested ingredients.
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