Fluorinated Oils and Cosmetics

by Ralph Hill - Internet Technology Researcher and Writerby Ralph Hill - Internet Technology Researcher and Writer

Of the many unusual (from a traditional perspective) chemicals finding their way in to modern cosmetics and skin care are fluorinated oils. A quick search regarding the development and uses of these specialty oils finds us looking at synthetic fluids commonly associated with air-conditioning. So how do oils used in such a dissimilar industry to beauty find its way in to cosmetics and skin care?

Fluorinated oils are more commonly associated with air-conditioningFluorinated oils are more commonly associated with air-conditioning

To understand why fluorinated oils are used in cosmetics we need to look at the properties of these oils. There are different types of fluorinated oils and the specific type of this article is the perfluorinated oils or perfluorocarbons (PFCs)
Perfluorinated oils are essentially silicone based fluids with oil like properties. One of the types of fluorinated oil used in cosmetics was patented by Daikin industries (Japanese Air-conditioning giant) who use PFCs in refrigeration as an alternative to CFCs. It was developed primarily due to its low temperature properties and (Fluorinated oils do not change viscosity at temperature extremes) higher density than water.
Perfluorocarbons are more importantly an inert and non-flammable alternative to Hydrocarbon oils.

These key properties of being inert, having no smell and colour, non-flammable, non-corrosive, low viscosity and hydrocarbon free along with low toxicity and short retention time in the body also makes them a good candidate for cosmetics, particularly in the use of make-up and skin care.

Fluorinated oils and other materials such as silicones obtain their properties by treatment with Fluorine: the most chemically reactive and electronegative of all the elements. Fluorine's large electronegativity and small atomic radius gives it remarkable bonding characteristics, particularly in conjunction with carbon.
Flourines properties are most recognised in the production of low friction plastics such as Teflon, (non-stick surfaces) and in halons such as Freon. (airconditioning fluids)

In cosmetics, fluorine-modified oil and silicone derivatives exhibit high water- and oil-repellency to provide cosmetics, which wear, long (increasing usable daily life span) and have a good feel on use.

Some powders used in cosmetics are also flourine treated, and the use of the fluorinated oils solve the oil repellency problems encountered with non-flouronated oils such as vegatable and mineral oils. Flouronated oils also exhibit low water absorption properties, another desirable feature for an oil in make-up.

The properties of perfluorodecalin has seen it used in a wide variety of applications including an artificial blood called Fluosol The properties of perfluorodecalin has seen it used in a wide variety of applications including an artificial blood called Fluosol

Perfluorodecalin (PFD)

One of the more interesting fluorinated oils is perfluorodecalin. This high purity perfluorocarbon is chemically and biologically inert, and its ability to dissolve (or physically carry) gases, (and more specifically oxygen) makes it especialy useful in medical and skin care applications.

PFD can in fact, dissolve large amounts of oxygen, (100 ml of perfluorodecalin at 25C will dissolve 49 ml of oxygen under certain conditions) and this property has seen it used in a wide variety of applications from an artificial blood called Fluosol to a component of storage mediums for organs and tissues for transplant.

Oxygenated perfluorocarbons administered in emulsions are known to increase surface oxygen concentration but without the need for a pressure chamber. Consequently, they are extremely useful for repair of scar tissue, leg ulcers and radiation burns. The same effect has been used to grow cell cultures.

As a development of the medical applications, perfluorodecalin is now used as an ingredient in several cosmetic and skin care products, where its ability to dissolve and carry gasses such as oxygen is belived to revitalise skin and help reduce wrinkles.
It is also lipophobic and hydrophobic forming a third phase which facilitates emulsion formulation.

Typical concentrations range between 5 20% depending on the type of formualtion, and it can be found in a wide variety of products including face & neck creams & gels, eye contour products, oxygen masks, and hair care. (Where its non-greasy and ability to prevent sebum build up is useful as a detangling agent)

Beneficial claims

As with many compounds and chemicals used in skin care products, the claims of what miraculous feats can be achieved is often driven by the marketers imagination and not the science.
There have been claims that some formulations containing as little as 6% perfluorodecalin can increase oxygen pressure in the skin by 100%. In one particular advertising statement, there is a claim that Perfluorodecalin delivers Pure Oxygen for rapid cell function. There are references to clinical trails and studies, however no specific details are provided.
In another brands marketing information, references are made to Perfluorodecalins role in gasotransportation, along with ensuring the 'aeration' of skincells. In another product, perfluorodecalin was listed in the ingredients as being a oxygen substitute. If all of this is factual, then Perfluorodecalin is indeed a highly benificial ingredient. However.....

The chemical structure of perfluorodecalin. Note there are no Oxygen atomsThe chemical structure of perfluorodecalin. Note there are no Oxygen atoms

While it is easy to get quite enthusiastic about Perfluorodecalin because of its medical successes as an artificial blood, we must understand that it does not actually contain any oxygen in its molecular structure. (it comprises of 10 Carbon atoms and 17 Flourine atoms)
Perfluorodecalin can indeed move oxygen, and this is facilitated by a process known as passive diffusion.
Passive diffusion takes advantage of gasses' affinity to move from areas of greater concentration to areas lesser concentration until it reaches a state of equilibrium.
In the human body, oxygen moves from the lungs (high concentration) to the blood (low concentration). Then, once the blood reaches the capillaries, the oxygen moves from the blood (high concentration) to the tissues (low concentration). The claims of the skin care marketers imply that the oxygen is taken or transported from the atmosphere (high concentration) and delivered through the bilayer membrane to lower levels of the epidermis. (Low concentration) This happens to a certain degree due to the passive diffusion characteristics of the oil, however while it is true that perfluorodecalin does indeed dissolve gases,(one of it's benificial properties) these gasses include carbon dioxide and nitrogen, so unless the perfluorodecalin in the formula is already fully saturated with oxygen, (or being applied in a pure oxygen envirionment) there are the obvious questions on how can it deliver pure oxygen to the skin surface.
The reality is of course, that due to the laws of physics, Perfluorodecalin can not transport or deliver more oxygen than it is surrounded by. Perhaps a little creative pseudoscience is employed by some skin care marketers?
Whatever the claims, Perfluorodecalin in skin care formulations does indeed have beneficial properties, but perhaps not so earth shattering and efficient as some assert. Research continues.

Other perfluorocarbons

Other variations typically used in cosmetics as skin conditioners, hair de-tanglers, solvents etc include: Perfluoromethylcyclopentane, Perfluoroperhydrophenanthrene, Perfluoro-1,3-dimethylcyclohexane, Perfluoromethyldecalin, and Perfluoroperhydrobenzyltetralin.

Typical perfluorocarbon properties

  • Odourless, colourless, non-volatile, low viscosity liquids
  • Non-sensitising, Non-irritant Non-greasy
  • Refreshes and smoothes the skin
  • Enhances the appearance of tacky and sticky final products
  • Can be used in colour products for enhanced colour endurance
  • Creates a third phase emulsion and acts as a co-emulsifier
  • Creates a thin film application with basic water proofing properties
  • Creates transient gel structure
  • Does not interfere with the normal function of the skin

Negative aspects

PFCs are recognised as extremely potent greenhouse gases, and they are a long-term problem with a lifetime up to 50,000 years.

PFCs are one of the classes of compounds regulated in the Kyoto Protocol.(The United Nations Framework Convention on Climate Change)

Most of the PFCs creating the greenhouse warming potential however, are from industrial use such as aluminium smelters.

The vow volume use in skin care and medical applications have no reported effect on the environment to date.


About the Author

Ralph Hill is technology writer, illustrator and editor for Virtual Beauty Corporation. He has a background in science, electronics and electro-mechanical devices, but enjoys researching and writing on a myriad of skin care related topics including cosmetic chemistry and anatomy & physiology.




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