In this part, we will see some example of the cosmetics product and the chemistry behind the products. Besides that, we will see how the chemistry can give the function of the different products.
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Woman at Her Toilette
Henri Marie Raymond de Toulouse-Lautrec-Monfa (1889) |
A cosmetic can be defined as a substance that is applied directly to the human body for "
cleansing, beautifying, promoting attractiveness, or
altering the appearance". Hence, this the example for cosmetic products:
Shampoo, hair dyes, hand and body soaps, skin creams, lipsticks, mascara, nail varnish, perfumes, colognes, deodorants, mouthwashes, anti-perspirants, toothpastes, and other cosmetics and toiletries.
However, some of them we have discussed in previous parts, (
Shampoo and hair dyes), so in this section we will try to discuss about skin creams, lipsticks, mascara, nail varnish, perfumes, colognes, and as well razor technology.
The recipe of cosmetics basically have been used for more than a millennium. In 1400 BC, three Egyptian females were buried with various cosmetics which are two jars contained a cleansing cream made of oil and lime. Besides that, ancient medical texts describe prescription for body 'scrub' lotions. In these days, the global cosmetics market is approximately £100 billion per year with UK cosmetics market is £1 billion per year in 2007.
Skin Creams
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| Skin Creams |
Generally, there are 2 types of skin creams, hand creams and face creams, and both of them are typically comprise oil droplets in water (emulsions). Besides that, most of skin creams contain humectants such as glycerol, propylene glycol, or sorbitol, which have characteristics of highly hydrophilic, very low volatility, and bind strongly to water to keep skin hydrated. Moreover, other components include silicone oils (e.g PDMS), paraffin, and fatty acid esters are also used for the formation of protective film on skin after oil has penetrated and water has evaporated.
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| Common chemicals for skin creams |
The use of PDMS in cosmetics is shown above in skin creams. The synthesis of PDMS in industry is shwon below:
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| The synthesis of PDMS in industry |
PDMS adds 'spreadability' and smoothness to product such as facial cosmetics, lotions, creams, anti-perspirants, and deodorants. In lipsticks, eye shadows and blushers, silicones enhance surface texture and provide longevity to help the product to stay on the skin and maintain its colour.
PDMS manufacturers such as Dow Corning see 'Personal Care' products as a major growth sector over the next decade, but Canada is seeking a PDMS ban. Besides that, this sector comprised 18% of its global silicone sales (22 000 tonnes) in 2002.
Lipsticks
Lipsticks provide a softening, protecting film for the lips, as well as colour ranging from soft and unobtrusive to dazzling. A typical lipstick formulation contains: purified castor oil (from plant-based triglycerides), other oils, waxes, hydrocarbons, esters, organic dyes and pigments, polymers, perfumes, preservatives, lanolin (a waxy sebum obtained from sheep).
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| Common organic dyes in lipstick |
Castor oil (typically 50% w/w of the lipstick) acts as a solvent for organic dye(s) and blend of oils and waxes tunes the melting point. It ensures that lipstick remains a waxy solid in its container, but it flows smoothly when it touches the lips.
Mascara
It is used to darken, thicken and define eyelashes and it was invented in 1913 by US chemist T.L. William for his sister. The original formulation was simply a mixture of coal dust and vaseline, and after that a mail order company, Maybelline, was founded in 1915.
A typical modern Mascara formulation contains:
Water, Iron oxides, poly(N-vinylpyrrolidone), carnauba wac, myristyl lactate, beeswax, glyceryl caprylate, paraffin, cetyl dimethicone, stearic acid, phenoxyethanol, parabens, hydroxyethyl cellulose, tocopherol acetate, magnesium silicate, panthenol (provitamin B5), silk amino acids.
Generally, the formulation can be translated as:
- Film formers: poly(N-vinylpyrrolidone), hydroxyethyl cellulose
- Skin conditioning agent and emulsifier: cetyl dimethicone, stearic acid, panthenol (provitamin B5), silk amino acids
- Pigment: Iron oxide
- Antioxidant: tocopherol acetate
- Fungicides and bacteriocide: parabens
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| Parabens |
Parabens is also used in shampoo, toothpaste, shaving gel, and moisturisers. Other ingredients act as anti-caking and bulking agent, moisturisers, humectants, etc.
Eye Shadow
In general, the chemical compositions of eye shadow consists of 2 parts, pigments and binders. The pigment that commonly used are:
- Ultramarine blue (an inorganic aluminosilicate comprising Al, O, Si, Na, and S)
- Iron oxides of various shades (including black)
- Chromium oxide for green
- Titanium dioxide. White pigment used for its excellent opacity; it hides or mutes the natural skin colour, hence modifying colours.
Besides the pigment, there is also binder, which commonly esters, lanolin, and/or hydrocarbons are used.
Nail polish
In nail polish, the compositions mainly are pigments, binder, and carrier. Firstly, ultramarine blue, organic pigments or dyes, iron oxides, or chromium oxide are used for the pigments. Then, the binder which has 2 types, solvent-based binder and aqueous-based binder. In solvent-based binder, nitrocellulose and plasticizer are used (it gives fast drying time), but in aqueous-based binder, film-forming poly(vinyl acetate) latex is used. The binder provides a dye-impregnated polymeric film that adheres to the nail on evaporation. Lastly is the carrier which generally is the mixture of hydrocarbons and esters (n-butyl acetate, ethyl acetate).
Besides nail polish, there is as well nail polish remover to remove the dye. Various solvents such as acetone, water, castor oil, linseed oil, triethanolamine (plus colourants) can be used as remover. The castor oil is an emollient, which means it can keep fingernails and surrounding skin soft. Besides the solvents, there is also the addition of 10 ppm of denatonium benzoate which the bitterest known compound. The purpose of this addition is to avoid children swallow the nail polish remover.
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| Denatonium benzoate |
Perfumes and Colognes
In general, the word perfume comes from latin,
per (through) and
fumus (smoke). Then, perfume comprises various synthetic chemicals, animal oils (e.g musk), extract of fragrant plants, etc. dissolved in denaturated ethanol. In the other hands, cologne comes from french which is
eau de Cologne (water of cologne, 1709) and cologne is much more dilute and less expensive versions of perfumes.
Nowadays, more than 4 000 aromatic plant and animal substances and more than 2 000 synthetic organic chemicals as essential oils are used by perfumers to formulate modern cosmetics and toiletries. The first synthesised essential oil was vanillin in 1871 which led to the development of modern synthetic perfumes.
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| Vanillin |
In blended fragrances, there are usually have 3 components which are:
1. The first impact, or top notes, which comes from volatile components that diffuse to the nose quickly. A typical example is phenylacetaldehyde.
2. The fundamental odour, or middle note, is produced by components such as 2-phenylethanol (aroma of roses).
3. The end note is a residual, longer lasting scent carried by substances like civeton, a cyclic organic compound with a musk-like odour. The end note of a perfume is the fragrance that lingers.
Moreover, in figure below, there are some common organic fragrances that is used in perfumes or colognes.
Chanel No. 5
Ernest Beaux created first 'wholly synthetic perfume' Chanel No. 5 for Coco Chanel in 1921 and this perfumers to regularly use aldehyde (2 methylundecanal) in his formulation.
Chanel No. 5 comprises:
- Top notes: aldehydes, neroli, lemon, etc.
- middle notes: ylang-ylang, jasmine, rose, etc.
- Base notes: vetiver, sandalwood, vanilla, etc.
Moreover, Chanel No. 5 actually contains 80 different ingredients and today a bottle of Chanel No. 5 is old every 30 seconds
Razor Technology and Styptic Pencil
Nowadays, Gillette (founded 1901) has 73% of global razor market by value. From the figure above, it is shown blue lubricious strip at the upper part which is a polymer of poly(ethylene oxide). In 1960s, there was a major technical innovation which teflon (polytetrafluoroethane)-coated razor blades. Teflon is used to coat the chromium steel razor blade because teflon can binds strongly chromium.
The razor tip of the blade is very sharp with just 30 nm wide (around 300 atoms). Then, initial thick teflon coating reduced to much thinner layer during first, so the first shave is actually not as good as subsequent shaves. Moreover, 20% of male consumers cannot tell the difference in performance between teflon-coated and uncoated razor, which the consumer perception is very important.
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| Gillette's Fusion (left) and Venus (right) |
In one of the Gillette's research laboratory at Reading, it was found that men use 30-1200 strokes per shave. This research was done by using a miniature camera within razor head. Hence, Gillette launched Fusion in 2006 which comprises 30 razor components and it has more than 20 patents. This research team spent 8 years of in-house research which included thousands of shaving studies conducted globally. Besides tha, Gillette also launched razors for women which is called Venus. It has the same technology, but different razor head. Venus has rounded head which so less obtrusive for arm-pit shaving. Furthermore, legs have fewer nerve ends, finer hair follicles than faces, so woman can happily use a relatively blunt razor for longer.
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| Styptic pencil |
Besides razor blade, there is another product that play a role in shaving, which is styptic pencil. Styptic pencils comprises active ingredients which is Al
2(SO
4)
3.and inactive ingredient (TiO
2). Cationic Al(III) causes a rapid coagulation of anionic red blood cells, which leads to rapid blood clotting, so it protects the skin from infection.
Lipsticks provide a softening, protecting film for the lips, as well as colour ranging from soft and unobtrusive to dazzling. A typical lipstick formulation contains: purified castor oil (from plant-based triglycerides), other oils, waxes, hydrocarbons, esters, organic dyes and pigments, polymers, perfumes, preservatives, lanolin (a waxy sebum obtained from sheep). 
In general, the chemical compositions of eye shadow consists of 2 parts, pigments and binders. The pigment that commonly used are:
In nail polish, the compositions mainly are pigments, binder, and carrier. Firstly, ultramarine blue, organic pigments or dyes, iron oxides, or chromium oxide are used for the pigments. Then, the binder which has 2 types, solvent-based binder and aqueous-based binder. In solvent-based binder, nitrocellulose and plasticizer are used (it gives fast drying time), but in aqueous-based binder, film-forming poly(vinyl acetate) latex is used. The binder provides a dye-impregnated polymeric film that adheres to the nail on evaporation. Lastly is the carrier which generally is the mixture of hydrocarbons and esters (n-butyl acetate, ethyl acetate). 
Nowadays, more than 4 000 aromatic plant and animal substances and more than 2 000 synthetic organic chemicals as essential oils are used by perfumers to formulate modern cosmetics and toiletries. The first synthesised essential oil was vanillin in 1871 which led to the development of modern synthetic perfumes.
1. The first impact, or top notes, which comes from volatile components that diffuse to the nose quickly. A typical example is phenylacetaldehyde.
2. The fundamental odour, or middle note, is produced by components such as 2-phenylethanol (aroma of roses).
Ernest Beaux created first 'wholly synthetic perfume' Chanel No. 5 for Coco Chanel in 1921 and this perfumers to regularly use aldehyde (2 methylundecanal) in his formulation.
Nowadays, Gillette (founded 1901) has 73% of global razor market by value. From the figure above, it is shown blue lubricious strip at the upper part which is a polymer of poly(ethylene oxide). In 1960s, there was a major technical innovation which teflon (polytetrafluoroethane)-coated razor blades. Teflon is used to coat the chromium steel razor blade because teflon can binds strongly chromium.
The razor tip of the blade is very sharp with just 30 nm wide (around 300 atoms). Then, initial thick teflon coating reduced to much thinner layer during first, so the first shave is actually not as good as subsequent shaves. Moreover, 20% of male consumers cannot tell the difference in performance between teflon-coated and uncoated razor, which the consumer perception is very important.
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