Why the use of Skin Cleansers ?

Is the use of skin cleansers an other form of commercial or is it really essential to people 's hygiene?

<< ...

-> Penetration of skin folds and follicles orifices by pure water is inefficient.

Bacteria and most types of dirt are not water soluble, and therefore, require large ammounts of water for removal from the skin

Part of the dirt and grime is redeposited on the skin if only a limited quantity of water is used. The final result is a mere redistribution of dirt, and not its removal.

To counteract these failings, surfactants are used to facilitate wetting of skin and prevent redeposition of dirt particles by emulsifying, solubilizing, and dispersing them. >>

Numerous surfactants, like the ones we saw in the chapter I wrote before : The surfactants : Defifintion[http://cosmetic-formulation-leeloutte.blogspot.com/2007/02/surfactants-definition.html] , have been developped in recent years and are contained in skin cleansers as shower gels.

Skin cleansers : A little bit of History

First, I want to thank you "Touchy" for your kindness and the book about surfactants you lent to me .. Merci à toi ^_^!!

For what's following, I will take the information as they are from that book, chapter "Surfactants For Skin Cleansers" PAUL THAU, Technology Surveillance, Inc., Clark, New Jersey.

<< Soap is the forerunner of modern-day skin cleansers and originated in the Ancient civilizations bordering the Mediterranean. The Phoenicians were certainly familiar with the use of soap as early as 600 B.C. They carried it to the South of France, and from there its use spread to Spain, Italy and Germany.

The importance of adequate skin cleansing to health was clearly proved after the soapmaker's art was lost with the fall of the Roman empire.

The soapless centuries between 500 A.D and 1500 A.D were notorious for the devastating plagues that nearly depopulated an unhygienic Western Europe.

Soap remained a rare commodity until about 1791 when the French surgeon Nicholas Leblanc discovered an inexpensive method of obtaining alkali from sodium chloride.

Within a decade, soap making techniques became available to all, and soap became an item of daily use. >>

After soaps, other skin cleansers appeared just as shower gels. We will see in the next chapter why all those skin cleansers are so important for hygien.

Shower gels

What are you searching for in a shower gel?


Do you want it to be extremely foaming or not too much? Do you like it light on the skin or do you like it to have a layer or "cream" on your skin while applying it along your body?


Actually, every shower gel is different, be it in the aspect, the touch side, the color or most importantly, its fragrance!



Actually consumers choose their shower gels considering the fragrance's aspect first. So, of course, the choice of the fragrance used is very important. And depending on the seasons or people's mood at a certain period of the year, the marketing service focuses a part of their work on this question. Especially when you developp a new product.



Actually, when you formulate a shower gel, it is a bit like when you buy this cosmetic. You smell the fragrance first, you look at the color, the aspect, and you try it at home to test its particularity on the skin, during and after the shower.



Of course it is a bit more complex, since you have to take in consideration the viscosity of the product for it to fit the exact requirements, but as a chemist technician just as a consumer, the feeling and reaction while having this product in your hand is quite similar. :-)



What is your favorite shower gel? And why do you like it particularly?

I hope someone will stop by and answer this question ;-)



See you for the little details about how formulating a shower gel is a bit different from formulating a white product (cream for instance).



^_^ I'm back ^o^!!

A little sorry message to all my readers.. you are becoming more and more numerous but also from many different countries worldwide!! wow, don't hesitate to leave comments here and there, I'd like to hear from you !! really.

So, a little bit from me since i've stopped writing here!! ^^
I have been to Korea, Seoul, for three months, from March of this year, and it was such a great experience!! Now I am back in France and I am so glad to live in Paris again.

It's been two weeks now that I found a work as a cosmetic formulator in Paris, and in the company I've already been to, for my training period! So I am so happy, since I already know some people there, and since work is so interesting! I am working on shower gels developpment! So i will be introducing shower gels a little bit through this blog later, when I have clear info on the subject to present to you all.

But for now, i don't have time for myself..but soon..soon!!

Let's keep reading!!

Thank you all. :-)

Emulsion Composition and Role

- " Composition of a classical cosmetic formulation :


Surfactants

Hydrosoluble Polymeres , thickeners

Preservatives

Antibacterians, antiseptic

Humectants and Moisterizers

Pigments

Perfumes

Colorants

Divers additives


photo taken from http://www.lavbeauty.com/skincare.jpg


Aqueous phase :

Composition :

- Sterilised/Deminerilised Water which serves as an excipient.

- Consistency Agents : Those are ploymers able to modify the reological comportment of formulations.

- Chelating Agents : molecule specialised in the capture and the immobilisation of ionic substances coming from cleansing water in order to reduice the risks of oxydation.

- Humectant Agents : added to limit the loss of water in the product.

- pH Regulator : to adjust the pH of the formula (to avoid the fact the product is agressive for the skin).

- Moistening Agents : provoke an immediat and long term effect of skin hydration.


Aqueous phase Functions :

- permits the development of viscosing polymers.

- Takes in actives, preservatives and colorants which are hydrosolubles.

- Restaurates the epidermis hydration by bringing elements able to fix water in the corneous layer of the skin, (elements as water and moisterizing agents).


- Oily phase :

Composition :

- Emollient : it nourishes the skin and play a role in the touchside and texture of the final product.

- Conditioning agents : form a film on the skin or hair to limit agression of surfactants.

- Surfactants : molecules permiting the formulation of the emulsion.

- Perfume phase : containing perfum, antioxydant, preservatives, solubilising.


Oily phase Functions :

- Takes in actives, preservatives, colorants which are liposolubles (soluble in oil).

- Participates to the hydrolipidic film reconstruction favorisating the conservation of the epidermis hydration.

- Gives a particular final touch to the formula.





Source : http://perso.orange.fr/chimie.sup/formulation.htm

The Surfactants : How does it work ?

Surfactants, have many functions.

That's what we are going to see.

" When used for stabilising an emulsion, surfactants are caracterised with their Hydrophilic - Lipophilic Balance (HLB).

___ 0 _____________________ 18 ___ HLB scale

more lipophilic

more hydrophilic

Surfactant Properties :

The Superficial Tension

Adding a surfactant product dicreases strongly the superficial tension of water with the disposition molecules take inside the liquid.


schema taken from http://images.google.fr/images?hl=fr&q=micelle&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;ie=UTF-8&oe=UTF-8&um=1&sa=N&tab=wi

It's this disposition which is responsible of the moistening, foaming and emulsioning power.

However reaching a certain concentration in surfactants, called critical micellar concentration (cmc), the surface of the liquid being satured in surfactant molecules, those molecules join theselves together in the liquid forming micelles.

Foaming power :

Surfactants molecules consolidate the thin water layer which forms bubbles.

Cleansing power :

Lipophile parts of surfactants adhere to oily dirt.

The dirt is then captured and carried away inside the micelles, to the washing water.

Emulsifing power


An emulsion is a system constituted by a liquid that is dispersed as thin droplets in an other liquid, both liquid being non miscible.

However, using surfactants, we can have droplets of oil in water or droplets of water into oil.

> A O/W (oil in water) emulsion must have a surfactant with High HLB

schema taken http://images.google.fr/images?q=micelle&ndsp=18&svnum=10&hl=fr&start=54&sa=N

> A W/O (water in oil) emulsion must have a surfactant with low HLB



micelle including a water droplet "






schema taken fromhttp://images.google.fr/images?q=micelle&ndsp=18&svnum=10&hl=fr&start=126&sa=N

> A " human micelle" I found while searching for schemas on the net..nice right? ;-)

photo taken from http://images.google.fr/images?q=micelle&ndsp=18&svnum=10&hl=fr&start=36&sa=N

source : http://www.ac-bordeaux.fr/Etablissement/StLouis/OLYMP/cosmeto/cosmeto.pdf

The Surfactants : Definition

Definition :

" The surfactants are able to disperse oily main parts in water (cleanser power), to form foam, to stabilise emulsions and to further the interfaces moistening.

Surfactants molecules posess a 6 atoms of carbon chain which is hydrophob ('doesn't like water'), and have a polar group hydrophile (who has affinity with water).

Those molecules having both hydrophob and hydrophile parts are called "amphiphile".

The molecule can be schematised this way :

---------------------O hydrophile part
hydrophob part



Classification :

a) Anionic Surfactant :

----------------(-) the hydrophile part is anionic

Different kind of anionic surfactants :

> derivees of fat acids : RCOO-,Na+ ( R : long chain in C12 to C18 the more often) resulting from saponification of triglycerids (triester of glycerol and fat acid) of vegetal oils.

example : sodium palmitate: CH3-(CH2)14-COO- , Na+

Where do we find them ?

N.B : Soaps containing the sodium ion are tough (we find them in bar of soap), those with potassium ion are smooth (used in shave foams or as surfactants in creams).

> alkylsulfates : R-O- SO3
- R = long chain of carbon : (synthetic detergents )

exemple : ammonium dodecyl sulfate or ammonium lauryl sulfate :
C12H25 – O – SO3- , NH4+

Where do we find them ?

present in toothpaste, shampoos, bath and shower products …

b) Cationic Surfactant :

--------------------(+) the hydrophile part is cationic

Kind of Cationic surfactants :

> quaternar ammonium salts : RR1R2R3 N+, allergising and irritating for eyes and skin, are often associed with other kind of surfactnats to attenuate those effects.

They have interesting bactericids properties.

Where do we find them ?

Their conditioning properties make them enter in after-shampoos formulation.

example : cetyltrimethylammonium bromure : C16-H33 N+ (CH3)3 , Br -

c) Non-ionic Surfactant :

The hydrophile part is neutral but strongly polar. Those elements are biologically safe.

> sorbates or esters of sorbitol and fat acids

> sorbitan esters (sorbitan : C6H12O5), and fat acids

Where do we find them ?

in emulsions but also numerous shampoos for their cleanser and foaming power.

d) Amphotere or Zwitterionic Surfactants

They possess two groupments of opposite charge. Following the pH they are under a cationic form or an anionic form.

> derivatives of betaine

> amine acid and their derivative which are often used in cosmetology as co-surfactant (in addition to principal surfactants) to stabilize micro-emulsion.

They are excellent cleanser.

Where do we find them ?

Non irritating, amphoteres enter in the formulation of :

- numerous soft shampoos

- products for sensitive skin

- eye demak up

- dermatological toners and gels "

source : http://www.ac-bordeaux.fr/Etablissement/StLouis/OLYMP/cosmeto/cosmeto.pdf and translated by me