1. Surfactants and Humectants in Cosmetics
Week 7
Surfactants and Humectants in Cosmetics

2. Surfactants Reduce Surface Tension
the word “surfactant” is a shortened form of the phrase “surface active ingredient.”
 This molecular composition means they have the ability to reduce the surface tension when placed into solutions of oil and water. 

3. How do cosmetic surfactants work?
the Critical Micelle Concentration (CMC) they arrange themselves in spherical structures called micelles.

4. Surfactants uses cosmetics
 practical applications of surfactants in cosmetics
1.Cleansing 2. Emulsification 3. Solubilization 4. Conditioning 5. Special effects

5. Cleansing Surfactants
The useful thing about micelles is that they can help suspend oil in water. When a small amount of oily materials is put into an aqueous solution of surfactants, it will migrate into the center portion of the micelle. So, when you put a surfactant solution on a surface like hair or skin, the oil that is there will be drawn away from the surface and into the micelles. When the surfactant solution is rinsed away, the surface is clean.

8. Emulsification
While cleansing cosmetics remove oils, many cosmetic products are design to add oily materials to the skin and hair. These ingredients usually can’t be applied directly because they have undesirable aesthetic characteristics in their concentrated form. For this reason, cosmetic chemists create emulsions using surfactants.

10. Solubilization
The problem with most emulsions is that they usually create opaque products. However, there are times when a cosmetic chemist wants a clear formula but still wants to blend an oil in a mostly water formula. Fortunately, there are surfactants that have the ability to create particles so small that light passes through them and the solutions remain clear. Molecules that do this are solubilizing surfactants. They are used to blend oily materials like fragrances or natural ingredients into clear solutions. An example would be a surfactant like Polysorbate 20.

12. Conditioning
Since surfactants often contain an “oily” part on their molecule, they have conditioning properties that can improve the feel and look of the surfaces of skin and hair. For them to work this way, the surfactants have to be left behind and also be non-irritating. This can be achieved through a leave-on cosmetic product or by using surfactants that can bond to surfaces through an electrostatic charge

14. Special effects
For example, some surfactants have anti-microbial effects so they can be used as a preservative. Certain surfactants can be used to create an elegant, pearly effect in cosmetics to increase their aesthetic appeal. They can be used for thickening systems, reducing irritation and improving formula stability.

16. humectants in cosmetics
Humectants (or moisturizers) are important cosmetic ingredients allowing to prevent loss of moisture thereby retaining the skin's natural moisture. Some compounds also have the ability to actively attract moisture.

17. cosmetic products, including shampoo, conditioner, frizz serum, lotions, creams, lip treatments, cleansers, after-sun lotion, and some soaps or body lotions
All humectants have common hydroxyl groups which allow them to participate in hydrogen bonding and attract water. This process attracts moisture from the outer layer of the skin or, in high humidity, from the atmosphere. 

19. Examples of some humectants include:
Propylene glycol, hexylene glycol, and butylene glycol
Glyceryl triacetate
Neoagarobiose
Sugar alcohols (sugar polyols) such as glycerol, sorbitol, xylitol, maltitol
Polymeric polyols such as polydextrose
Quillaia
Urea
Aloe vera gel
MP diol
Alpha hydroxy acids such as lactic acid
Honey
Lithium chloride