Chemistry for Cosmetics Dr Lida Schoen Amsterdam

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Chemistry of hair and skin products Hair in form 1775 today Lida Schoen Chemistry of hair and skin products

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

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

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

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

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

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

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

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

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

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

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

Developers and couplers Lida Schoen Chemistry of hair and skin products

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

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

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

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

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

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

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

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