ChemistryChemistryforfor

CosmeticsCosmetics

Dr Lida SchoenDr Lida SchoenAmsterdamAmsterdam

Lida Schoen Chemistry of hair and skin products 2

Human skinHuman skinHuman skinHuman skin

Lida Schoen Chemistry of hair and skin products 3

‘‘Dirt’ on the skinDirt’ on the skin‘‘Dirt’ on the skinDirt’ 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 soapCleaning the skin: water and soapCleaning the skin: water and soapCleaning the skin: water and soap

Lida Schoen Chemistry of hair and skin products 5

Washing dirt from textilesWashing dirt from textilesWashing dirt from textilesWashing dirt from textiles

with water and soap

Lida Schoen Chemistry of hair and skin products 6

‘‘Cosmetic’ cleanersCosmetic’ cleaners‘‘Cosmetic’ cleanersCosmetic’ cleaners

Showergel (=shampoo)

Lida Schoen Chemistry of hair and skin products 7

‘‘Cosmetic’ emulsionCosmetic’ emulsion‘‘Cosmetic’ emulsionCosmetic’ emulsion

• Water• Oil• Emulsifier• Additions

– Perfume– Colour

Lida Schoen Chemistry of hair and skin products 8

Emulsion: microEmulsion: microEmulsion: microEmulsion: micro

Lida Schoen Chemistry of hair and skin products 9

Emulsion: macroEmulsion: macroEmulsion: macroEmulsion: macro

Lida Schoen Chemistry of hair and skin products 10

CreamCream

• 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

Flowers, herbalsFlowers, herbals

Lida Schoen Chemistry of hair and skin products 12

Hair under microscopeHair under microscopeHair under microscopeHair under microscope

Lida Schoen Chemistry of hair and skin products 13

Chemistry: keratinChemistry: keratin

• Hydrogen bridges

• Ion-ion (salt) bonds

• Disulfide (sulpher) bonds

Lida Schoen Chemistry of hair and skin products 14

Keratin (2)Keratin (2)

Lida Schoen Chemistry of hair and skin products 15

Keratin (3)Keratin (3)

pH = 5,5pH = 5,5

Lida Schoen Chemistry of hair and skin products 16

Keratin (4)Keratin (4)

cystin

Lida Schoen Chemistry of hair and skin products 17

All bonds (schematic)All bonds (schematic)

Lida Schoen Chemistry of hair and skin products 18

Lida Schoen Chemistry of hair and skin products 19

Melanin in cortexMelanin 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

Lida Schoen Chemistry of hair and skin products 21

HaHaiir colourr colour

Lida Schoen Chemistry of hair and skin products 22

Hair cleaning: shampooHair cleaning: shampooHair cleaning: shampooHair 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

Ether sulfatesEther sulfatesEther sulfatesEther 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: electrolyteThickener: electrolyteThickener: electrolyteThickener: electrolyte

• detergent in water: micelles

• NaCl (3-4%)

Lida Schoen Chemistry of hair and skin products 25

Conditioner in the past: egg yolkConditioner in the past: egg yolkConditioner in the past: egg yolkConditioner in the past: egg yolkEgg shampoo:• Egg yolk: lecithin

Conditioner today: man madeConditioner today: man made•quat = quaternary ammonium compound•silicone

Lida Schoen Chemistry of hair and skin products 26

HaHaiir in formr in form 1775

today

Lida Schoen Chemistry of hair and skin products 27

Hair gel at schoolHair 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

Bleaching (1)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

• 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.

Bleaching (2)Bleaching (2)

Lida Schoen Chemistry of hair and skin products 30

Types of haTypes of haiir r cocolloouurriinngg

– permanent

– semi-permanent– temporarily

• OxidativeOxidative

• DirectDirect

Lida Schoen Chemistry of hair and skin products 31

HaHaiir r cocolloouurriinngg productsproducts

• Natural• Metal• Permanent (synthetic dyes)• Semi-permanent (natural en synthetic dyes)• Temporarily (synthetic dyes)

Lida Schoen Chemistry of hair and skin products 32

Lida Schoen Chemistry of hair and skin products 33

Lida Schoen Chemistry of hair and skin products 34

hennawalnut

Lida Schoen Chemistry of hair and skin products 35

Semi-permanent haSemi-permanent haiir r cocolloouurriinngg

• in and under cuticle• 4-6 washings• till 30% grey covering

Lida Schoen Chemistry of hair and skin products 36

Metal ‘dyes’Metal ‘dyes’Metal ‘dyes’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 haPermanent haiir r cocolloouurriinnggPermanent haPermanent haiir r cocolloouurriinngg

• Oxidative dyes: ‘development’ with hydrogen peroxide

• Not washable• Till 100% grey covering

Lida Schoen Chemistry of hair and skin products 38

Developers and couplersDevelopers and couplersDevelopers and couplersDevelopers and couplers

NH2

NH2

NH2

NH2

CH3

NH2

OH

NH2

OH

CH3

NH2

OH

NH2

NH2

OH

OH

NH2

OH

CH3

Ontwikkelaars

Koppelaars

p-Fenyleendiamine Tolueen-2,5-diamine p-Aminofenol 4-Amino-m-cresol

m-Fenyleendiamine m-Aminofenol p-Amino-o-cresol Resorcinol

= developers

= couplers

Lida Schoen Chemistry of hair and skin products 39

Examples of couplingsExamples of couplingsExamples of couplingsExamples of couplings

Lida Schoen Chemistry of hair and skin products 40

Summary chemical ‘trick’Summary chemical ‘trick’Summary chemical ‘trick’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

Bath saltsBath saltsBath saltsBath salts

1. Salt1. kitchen salt: NaCl (cheap, crystals)

2. soda : Na2CO3 (softener)

3. bicarbonate: NaHCO3 (solubility)

4. phosphate: Na3PO4 (complexer)

2. Perfume

3. Colour (water soluble food colour)

4. Extra (chamomile, herbals)

Lida Schoen Chemistry of hair and skin products 42

Perfume (1)Perfume (1)Perfume (1)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

citrusgreenfruity

lime, lemon ,mandarin, orange, grass, apple,pineapple, cassis, raspberry, peach

TOP

MIDDLE

BASE

floral

woodypowdery

jasmin, rose, violet,muguet

sandalwood,cedarwood,ambery, musky,vanilla, sweet hay

Lida Schoen Chemistry of hair and skin products 44

‘‘Our’ Chanel AllureOur’ 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

DilutionDilution

• 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 DescriptionAllure – Fragrance DescriptionAllure – Fragrance DescriptionAllure – 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.