HAIR AND SKIN CARE

Through our modem lifestyles wc have become accustomed to chemical-based products that clean and protect our hair and skin. These include soaps, shampoos, conditioners, moisturizers, sunscreens, and many other products formulated to help us maintain a healthy look. 

The essential ingredients of all these hair and skin products are part of a broad class of compounds called surfactants, which is short for surface active agents. All surfactant molecules are polar on one end and nonpolar on the other. Because of their nonpolar ends, they resist dissolving In water and instead cling to water s surface where their nonpolar ends stick up out of the water. Pour some oil onto the surfactant containing water and the nonpolar tails will cling to the oil s surface. In this way, surfactants bind together the surfaces of water and a nonpolar material. 

With a little agitation, the surfactant s surface-seeking behavior causes the formation of high-surface-area suds. With such an increased surface area, significant amounts of the oil are able to mix in with the water, forming a single phase known as an etvulsion.So, surfactants don t help nonpolar materials to dissolve in water. Instead, they just help these two materials to become very mixed. 

The prototypical shampoo surfactant Is the detergent sodium lauryl sulfate, (see Section 7.4.) A big advantage of detergents Is that in hard water they don t form 

Add UV-absorbing compounds to a skin moisturizer and you have sunblock lotion. Making a sunblock lotion water resistant, however, is problematic. Upon exposure to water, the surfactants within the lotion help to remove the lotion. Manufacturers generally recommend that you reapply the lotion after swimming. Lotions that minimize the use of surfactants have increased water resistance, but they tend to be oily or greasy. For these reasons, many water-resistant formulas include compounds that polymerize into a nonpolar, water-resistant film that helps to hold the sunscreen agent on the skin when wet. 

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Lanolin is a wax made in the sebaceous glands of sheep and washed out of wool with detergents. It is used in many hair- and skin-care products. 

Sodium PCA is hygroscopic, attracting moisture from the air. It is used as a humectant (moisturizer) for hair- and skin-care products. It is a stronger hydrating agent than the traditional compounds used for this purpose, such as glycerin, propylene glycol, or sorbitol. 

Discussed here are only the main chemicals used to formulate hair-and skin-care products. As any casual look at an ingredients list tells you, there are many other chemicals that serve other purposes. 

Synthetic surfactants are commonly used in shampoos, sometimes for reasons of cost and sometimes for performance. Non-ideal mixing in micelles can result when the repulsions between different surfactant head-groups are not uniform, such as when an anionic sulfonate is mixed with a non-ionic ethoxylate or when an anionic is mixed with a betaine. This causes the cmc of the mixture to be smaller than would be the case for ideal mixing, or for either surfactant alone. Such a reduction in cmc can be used to reduce the surfactant monomer concentration in a shampoo. This is an advantage since reducing the monomer concentration reduces the amount of eye and skin irritation experienced when the shampoo is used [904], Other synthetics offer other benefits. For example, some silicone surfactants can not only function as emulsifiers in hair and skin care products, but also act to improve feel, gloss, sheen, emolliency, conditioning and foam stabilization [905]. 

With these properties, saponified polyvinyl acetate-silicone copolymers can be used in cosmetic formulations (e.g., for hair and skin care) such as shampoos, lotions, and cremes or as a fabric care agent. 

Use To reduce overall irritancy from other ingredients in hair- and skin-care preparations. 

Aqueous viscoelastic surfactant solutions for hair and skin care are disclosed in U.S. Patent 5,965,502. Rheology conditions are specified for optimum flow behavior, in terms of the shear modulus as a function of temperature and pH. A representative graph of the storage and loss modulus as a function of angular frequency is presented in the patent and this is shown in Figure 4.8. Cited compositions contain anionic, betainic, and nonionic surfactants, electrolytes, and a water-soluble polymer. A nonionic gel personal cleanser is specified in U.S. Patent... 

Nonsubstantive photofilters, such as salicylic acid derivatives and octyl methoxycinnamate or benzophenone derivatives, have been included in leave-on formulations for skin and hair. Revlon possesses a patent describing the use of benzophenone and PABA derivatives with cationic surfactants and nonionic film formers in a mousse for hair protection [84], L Oreal has included camphorbenzalkonium sulfate as a proprietary photofilter in hair and skin care formulations [85-92],... 

AqiM-Tein C. [Mi rodc] Animal collagen amino acids and acetamide MEA moisturizer, substantivity agent fa hair and skin care MTods. 

BloCare . [Amerchol Amerchol Europe] Hyaluronic acid derivs. emollient, humectant, conditioner, softener, moisturizer, lubricant f( r hair and skin care prods. 

BimnintB. [Brodcs Industries] Minoal protein derivs. moisturizer for hair and skin care cosmetics. 

Cationic Collagen Polypeptides. [May-brotd ] Cationic collagen polypepdd substantivi agent, film former, protective colloid for hair and skin care prods. 

Collagen Hydrolyzate Cosmetic. [May-brook] Hydrolyzed collagen protective colloid film former, moisturizer, substantivity agent for hair and skin care prods. 

Copolymer 845, 937,958. aSF] PVP/ dimethylaminoethyl methacrylate copolymer film-forming resin, conditioner for hair and skin care prods. 

HydrocolL [Brooks Industries] Geladn or cdlagen ods. for hair and skin care cosmedcs. 

Kera-Qimt WKP. [Mt brodt] Coco-dimonium hydroxyprcqryl hydrolyzed keratin substantivity agent, moistur-izo, protective film-formn fta hair and skin care prods. 

Lonza Insta-Pearl . [Lonza] Proprietary blend pearlescent for hair and skin care pr. ... 

Mirapd . [Rhone-Poulenc Surf. Rhone-Poulenc France] Polyquatemiums polymer for hair and skin care prods. conditioner, antistat emollient, lubricant... 

N-Hance. [Aqualon] Guar hydroxy-propyltrimonium chloride substantive polymerfor hair and skin care fuods. 

Quat-Pro. [Maybrotde] Hydrolyzed protein derivs. cadonic substantivity agent, moisturizer, film-former to hair and skin care prods. 

Quat-Soy. Prooks Industries] Hydrolyzed soy protein ods. to hair and skin care cosmetics. 

Qninta Pro Cone. [Mt rook] Hydrolyzed coUi en, ttiedioninm hydrolyzed ctdlagen efoosulfaie, cadonk ocdlagen polypqitides, hydrolyzed keratin, collagen amino acids xoiein blend for hair and skin care prods. 

Solo-Veg. [Brodts Industries] Hydrolyzed v etable protein or blends ft)r hair and skin care cosmetics. 

Soy-Quat C. (Mt lnook] Cocodimo-nium hydroxypropyl hydrolyzed soy protein cationic subsundvi i ent, conditioner, moistuTizer for hair and skin care prods. 

Belsil. [Wacker Chemie GmbH Wacker Silicones] Silicotte compds. condi-tkmer for hair and skin care prods., deccxative cosmetics. 

EmCon. [Fanning] Lecitiiin emollioit, moisturizer, emulsifier, superfatting agent, humectant, mold rdease agent fn hair and skin care prods. 

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