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Types of Surfactants
Anionic surfactants:
Anionic surfactants carry a negative charge when ionized. It provides a lot of lather and detergency in the shampoo. The most commonly used anionics are sodium laureth sulphate and sodium lauryl sulfate. Sodium, ammonium, and triethanolammonium (TEA) lauryl sulfates are often found in hair care shampoos. These ingredients can be harsh and irritating to the scalp.
Cationic surfactants:
Cationic surfactants carry positive charge when ionized. They do pose a dangerous threat to the eyes if used in large quantities. The gentleness of your hair care shampoo depends on the surfactant used. Cationic molecules have the ability to cling to wet surfaces by static attraction. Consequently they are not removed during the rinsing process and form the basis of conditioning.
Nonionic surfactants:
Nonionic surfactants have no charge to the molecule, it is not used as a cleaning agent, but are often used in combination with the primary cleanser to change or modify it's actions. They can strip the hair and lead to scalp irritation due to excessive defatting. These include laureth-3 or 4, cocamide DEA or coco glucosides. We explore some of these in future research articles.
Amphoteric surfactants:
Amphoteric surfactant carries both positive and negative charges when ionized. They are very useful for decreasing the irritancy of a formulation while increasing the active content level of the product and quality of the lather produced. Each amphoteric surfactant has cationic and anionic charge groups, positive and negative. Most amphoteric shampoo surfactants are used in baby shampoos, because they are gentle and won't burn the eyes. By far the most used is cocamidopropyl betaine, or occasionally cocamido betaine.
Surfactant Functions in Shampoo
Surfactants will influence six essential attributes of shampoo: cleansing, foam, condition, viscosity and aesthetic appeal combined with safety and mildness in use.
Cleansing:
Cleansing is a function of the primary surfactant. To be an effective cleansing agent the surfactant system must work quickly at a relatively low temperature. It must also be effective in hard and soft water, be able to remove lipids and other soils and residue left after previous hair treatments and it must not leave any residues of its own. It must be non-toxic and reasonably non-irritant to skin and eyes.
Foam:
Foam is also a function of the primary surfactant. The main ingredients used for this purpose for decades are ALS and SLES.
Conditioning:
There are many ways of improving hair conditions. SLES and other anionic surfactants leave the hair feeling dry and difficult to manage. The introduction of a suitable secondary surfactant reduces this.
Viscosity:
Products must have sufficient viscosity to stay on the palm of the hand prior to application but must not come out of the bottle as a lump. Anionic systems may be thickened by the addition of electrolytes or non-ionic compounds or by betaines.
Aesthetic Appeal:
Although color, odor and pretty pictures on the label are essential factors for aesthetic appeal, the products appearance is also important. It must be opaque or clear. Clarity requires the complete solubility of all ingredients.
Safety and Mildness:
These are essential attributes of a hair care product that may be used every day and which can come into contact with the skin and eyes. Alkyl Sulfates and alky ether sulfates are aggressive surfactants that can irritate eyes and scalp and cause skin dryness.
I hope this information has given you a better understanding of the inter-workings of hair care shampoo. I will leave the answer of whether it's shampoo or a chemical cocktail up to you. One fact is certain, there are an awful lot of chemicals in that shampoo bottle in your bathroom.
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These statements have not been evaluated by the Food and Drug Administration and are not intended to diagnose, treat, cure or prevent any disease. |
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