1. Chemistry for Cosmetics
Dr Lida Schoen
Amsterdam

2. Chemistry of hair and skin products
Human skin
Lida Schoen
Chemistry of hair and skin products

3. Chemistry of hair and skin products
‘Dirt’ on the skin
water soluble (sweat);
oil soluble (sebum, grease);
non soluble (sand, skin flakes).
Rubbing with water and soap can remove all three.
Lida Schoen
Chemistry of hair and skin products

4. Cleaning the skin: water and soap
Lida Schoen
Chemistry of hair and skin products

5. Washing dirt from textiles
with water and soap
Lida Schoen
Chemistry of hair and skin products

6. Chemistry of hair and skin products
‘Cosmetic’ cleaners
Showergel (=shampoo)
Lida Schoen
Chemistry of hair and skin products

7. Chemistry of hair and skin products
‘Cosmetic’ emulsion
Water
Oil
Emulsifier
Additions
Perfume
Colour
Lida Schoen
Chemistry of hair and skin products

8. Chemistry of hair and skin products
Emulsion: micro
Lida Schoen
Chemistry of hair and skin products

9. Chemistry of hair and skin products
Emulsion: macro
Lida Schoen
Chemistry of hair and skin products

10. Chemistry of hair and skin products
Cream
2-3% emulsifier + thickener (for stabilisation)
10% oil like
mineral like paraffin (cheap, doesn’t deteriorate)
vegetable like avocado (what’s good to eat …),
animal like mink (snob appeal)
Water
Perfume
Additive, like
dihydroxyacetone (artificial tanning)
herbals
Lida Schoen
Chemistry of hair and skin products

11. Chemistry of hair and skin products
Flowers, herbals
Lida Schoen
Chemistry of hair and skin products

12. Chemistry of hair and skin products
Hair under microscope
Lida Schoen
Chemistry of hair and skin products

13. Chemistry of hair and skin products
Chemistry: keratin
Hydrogen bridges
Ion-ion (salt) bonds
Disulfide (sulpher) bonds
Lida Schoen
Chemistry of hair and skin products

14. Chemistry of hair and skin products
Keratin (2)
Lida Schoen
Chemistry of hair and skin products

15. Chemistry of hair and skin products
Keratin (3)
pH = 5,5
Lida Schoen
Chemistry of hair and skin products

16. Chemistry of hair and skin products
Keratin (4)
cystin
Lida Schoen
Chemistry of hair and skin products

17. Chemistry of hair and skin products
All bonds (schematic)
Lida Schoen
Chemistry of hair and skin products

18. Chemistry of hair and skin products
Lida Schoen
Chemistry of hair and skin products

19. Chemistry of hair and skin products
Melanin in cortex
Eumelanin
black-brown;
large molecules;
easy to light up.
Pheomelanin
yellow-red;
smaller molecules;
difficult to light up.
Lida Schoen
Chemistry of hair and skin products

20. Chemistry of hair and skin products
Lida Schoen
Chemistry of hair and skin products

21. Chemistry of hair and skin products
Hair colour
Lida Schoen
Chemistry of hair and skin products

22. Hair cleaning: shampoo
Detergent: sodium lauryl (=C12) ether sulphate:
cheap
skin friendly
good foam
easy to thicken (with NaCl)
Lida Schoen
Chemistry of hair and skin products

23. Chemistry of hair and skin products
Ether sulfates
Vegetable oil, after hydrolysation and reduction, ethoxylation with ethylene oxide
Alkyl alcohol esterified with sulphuric acid: CH3-(CH2)10-CH2(OCH2CH2)n)OSO3- Na+ with 1<n<4
Lida Schoen
Chemistry of hair and skin products

24. Thickener: electrolyte
detergent in water: micelles
NaCl (3-4%)
Lida Schoen
Chemistry of hair and skin products

25. Conditioner in the past: egg yolk
Egg shampoo:
Egg yolk: lecithin
Conditioner today: man made
quat = quaternary ammonium compound
silicone
Lida Schoen
Chemistry of hair and skin products

26. Chemistry of hair and skin products
Hair in form
today
Lida Schoen
Chemistry of hair and skin products

27. Chemistry of hair and skin products
Hair gel at school
Carbomer (brand name in Europe): neutralised cross linked polymer of acrylic (propene) acid
CH2=CH-COO-Na+
Lida Schoen
Chemistry of hair and skin products

28. Chemistry of hair and skin products
Bleaching (1)
Decomposition of melanin by oxidation in alkaline (ammonia) environment;
carboxylated derivatives soluble at higher pH’s.
Lida Schoen
Chemistry of hair and skin products

29. Chemistry of hair and skin products
Bleaching (2)
Bleaching powder: persulphate: (O3S-O-O-SO3)2-
2 Na2S2O8 -> 2 Na2S2O7 + O2
Hydrogen peroxide, (max. 12%, pH = 4), optimum melanin bleaching at pH  pKa (11,5) of the peroxide-anion.
In practice: pH = 10. H2O2(aq) 12% not stable at pH = 10.
Lida Schoen
Chemistry of hair and skin products

30. Types of hair colouring
permanent
semi-permanent
temporarily
Oxidative
Direct
Lida Schoen
Chemistry of hair and skin products

31. Hair colouring products
Natural
Metal
Permanent (synthetic dyes)
Semi-permanent (natural en synthetic dyes)
Temporarily (synthetic dyes)
Lida Schoen
Chemistry of hair and skin products

32. Chemistry of hair and skin products
Lida Schoen
Chemistry of hair and skin products

33. Chemistry of hair and skin products
Lida Schoen
Chemistry of hair and skin products

34. Chemistry of hair and skin products
walnut
henna
Lida Schoen
Chemistry of hair and skin products

35. Semi-permanent hair colouring
in and under cuticle
4-6 washings
till 30% grey covering
Lida Schoen
Chemistry of hair and skin products

36. Chemistry of hair and skin products
Metal ‘dyes’
Acetates or sulphates of: lead, silver, iron, copper, cobalt, bismuth, manganese, zinc
Sulphide bonds with sulphur from keratin
Toxic properties!
Sensitive to oxidation
Lida Schoen
Chemistry of hair and skin products

37. Permanent hair colouring
Oxidative dyes: ‘development’ with hydrogen peroxide
Not washable
Till 100% grey covering
Lida Schoen
Chemistry of hair and skin products

38. Developers and couplers
Lida Schoen
Chemistry of hair and skin products

39. Chemistry of hair and skin products
Examples of couplings
Lida Schoen
Chemistry of hair and skin products

40. Summary chemical ‘trick’
Mix two (or more) kinds of small molecules;
cover hair with mixture;
small molecules intrude the hair cortex (higher pH will help to open cuticula);
inside the cortex small molecules react to much bigger molecules;
The big molecules are captured in the cortex, they can’t leave: permanent hair dye
Lida Schoen
Chemistry of hair and skin products

41. Chemistry of hair and skin products
Bath salts
Salt
kitchen salt: NaCl (cheap, crystals)
soda : Na2CO3 (softener)
bicarbonate: NaHCO3 (solubility)
phosphate: Na3PO4 (complexer)
Perfume
Colour (water soluble food colour)
Extra (chamomile, herbals)
Lida Schoen
Chemistry of hair and skin products

42. Chemistry of hair and skin products
Perfume (1)
Natural (past) and synthetic (aldehydes, ketones, esters)
Mixture of 3 groups ‘notes’:
Top;
Middle;
Base.
Lida Schoen
Chemistry of hair and skin products

43. Chemistry of hair and skin products
TOP
lime, lemon ,
mandarin, orange, grass, apple,
pineapple, cassis, raspberry, peach
citrus
green
fruity
MIDDLE
jasmin, rose, violet,
muguet
floral
sandalwood,
cedarwood,
ambery,
musky,
vanilla,
sweet hay
BASE
woody
powdery
Lida Schoen
Chemistry of hair and skin products

44. Chemistry of hair and skin products
‘Our’ Chanel Allure
citrus: 15 drops (top)
lily of the valley: 8 drops (top/ middle)
rose: 2 drops (middle)
jasmin: 10 drops (middle)
floral bouquet: 5 drops (middle)
sensual: 10 drops (base)
Lida Schoen
Chemistry of hair and skin products

45. Chemistry of hair and skin products
Dilution
With min 70% alcohol
Denaturated (tax reasons) with bergamot (citrus) or DEP (di-ethylphtalate)
Perfume: 20% oils
Eau de Toilette: 5% oils
Lida Schoen
Chemistry of hair and skin products

46. Allure – Fragrance Description
From the Chanel website:
The concept of Allure was Coco Chanel’s ideal: an innocent seduction without artifice, an unforgettable elegance transcending words and conventions.
Fragrance family: floral, fresh, oriental. A faceted fragrance that mixes notes of the Orient with abstract flowers.
A simple jewel that combines 6 complex facets. In Allure, you’ll find bergamot, mandarin, water lily & magnolia, jasmine and may roses, vetiver and finally, the velvety sensuality of vanilla.
Lida Schoen
Chemistry of hair and skin products