Dimethicone (Polydimethylsiloxane)

What is Dimethicone (Polydimethylsiloxane)?

Dimethicone (Polydimethylsiloxane) Molecular Formula: (C2H6OSi)

Molecular Weight: Between 5000-100000.

Chemical Name: Polydimethylsiloxane

CAS Number: 9006-65-9

It is known by two names. One of these is Dimethicone and the other is Polydimethylsiloxane. It is referred to as silicone oil. It is a silicone-based polymer.

It is a chemical with viscoelastic properties. For this reason, it has been observed to have moisturizing effects on human skin.

Dimethicones are among the most commonly used elastomers. It is the simplest member of the silicone family.

Other names are as follows;

• Dimethicone
• Dimethicone
• Polydimethylsiloxane
• Polydimethylsiloxane
• Dimethyl Silicone
• Methyl Silicone
• Silicone Oil
• Emulsified Silicone Oil
• Polymer
• Silicone
• Emulsifier
• 9006-65-9
• PDMS
• Elastomer
• Organic Silicone Oil
• DM 350
• DM 1000
• DM 5000

How is it Produced?

The production of silicone oils is obtained by reacting Octamethylcyclotetrasiloxane and Hexamethyldisiloxane in the presence of concentrated sulfuric acid and in the presence of tetramethylammonium hydroxide catalyst.

What are the Physical and Chemical Properties of Dimethicone?

It is a viscous liquid in a transparent form that is tasteless, colorless, odorless, and non-toxic.

Viscosity varies according to molecular weight. Accordingly, as the molecular weight increases, the viscosity increases. Kinematic viscosity ranges between 10-6 and 10+6.

As for solubility, it dissolves well in benzene. In addition, it has partial solubility in Toluene, Xylene, ethyl ether, butanol, and ethyl alcohol. It is slightly soluble in acetone. It is not soluble in paraffin oil and vegetable oil. Similarly, it is not soluble in water.

It has chemical stability.

Its density at 25 °C is 0.963 g/cm3.

Dimethicone (Polydimethylsiloxane) Melting point is -50 °C.

Boiling Point: 200-300 °C (varies)

What are the Types of Dimethicone (Polydimethylsiloxane)?

Polydimethylsiloxane types vary according to their viscosities. These are as follows.

• 1.5= Viscosity 1.5 mm2/s (Volatile Silicone)
• 2= Viscosity 2 mm2/s (Volatile Silicone)
• 3= Viscosity 3 mm2/s (Volatile Silicone)
• 4= Viscosity 4 mm2/s (Volatile Silicone)
• 5= Viscosity 5 mm/s (Volatile Silicone)
• 10= Viscosity 10 mm2/s (Volatile Silicone)
• 20= Viscosity 20 mm2/s (Volatile Silicone)
• 50= Viscosity 50 mm2/s (Volatile Silicone)
• 100= Viscosity 100 mm2/s (Volatile Silicone)
• 200= Viscosity 200 mm2/s (Volatile Silicone)
• 350= Viscosity 350 mm2/s (Volatile Silicone)
• 500= Viscosity 500 mm2/s (Volatile Silicone)
• 1000= Viscosity 1000 mm2/s (Volatile Silicone)
• 12500= Viscosity 12500 mm2/s (Volatile Silicone)
• 60000= Viscosity 60000 mm2/s (Volatile Silicone)

What is the Role of Polydimethylsiloxane (PDMS) in Pharmaceutical Applications?

There are some conditions for a dimethicone to be legally considered an active drug class. Silicone in the pharmaceutical industry must be National Formulary (NF) grade.

This type of PDMS is used as an active OTC with its high hydrophobic property and partial protection it can offer with some water-immiscible effects. The properties that make these silicone polymers stand out in the pharmaceutical and cosmetic industries are as follows.

• It provides not only lubricity properties but also good emollient properties due to having a surface tension lower than critical surface wetting tensions.
• Low molecular weight PDMS cyclic oligomers act in cream formulations to provide treatment against acne and psoriasis.
• Low molecular weight linear PDMS oligomers function as a volatile carrier and solvent instead of different propellants.
• The boiling point of some polydimethylsiloxanes is 100 °C. In comparison, its heat of evaporation is lower than water. It has hydrophobic properties. Its non-burning sensation on the skin in formulations made by mixing with Ethyl Alcohol explains why this type of PDMS is used as an ingredient for anhydrous antifungal conditions.
• High molecular weight Polydimethylsiloxanes are resistant to washing after penetrating the body. It ensures that UV absorbers do not easily come off the body in case of contact with seawater. In this way, it helps in the manufacture of water-resistant sunscreens.
• High molecular weight polydimethylsiloxane can be highly hydrophobic. However, it is quite permeable to moisture and gases. Therefore, it has an abrasive effect in the application area. These are undesirable properties. Scientists are conducting studies to eliminate these inconveniences of silicones such as PDMS in the pharmaceutical and cosmetic industries.

What are the Usage Areas of Dimethicone (Polydimethylsiloxane)?

• The most common among the usage areas is the Cosmetics industry. In this field, it has excellent hydrophobic moisture resistance and good light transmittance. Due to its oil properties, it is heavily used in the manufacture of skin care products because it fills fine lines on the skin and fills irregular skin textures.
• It is used in the manufacture of makeup materials, body lotions, moisturizers in the cosmetics industry, and hair conditioners.
• It is also used in personal care products because it provides emollient properties.
• Dimethicone (Polydimethylsiloxane) natural silicone derivatives provide a smooth feel to the skin by creating a permeable barrier, preventing moisture loss from the skin.
• It is used in the manufacture of products used to eliminate skin irritations caused by diapers on baby skin. Here, it increases moisture while reducing itching and irritation.
• It is used in shampoos, hair conditioners, and the manufacture of hair care products.
• It can be used as a surfactant, antifoaming chemical.
• Dimethicone (Polydimethylsiloxane) is used in the manufacture of root canal sealers.
• Silicone oils are used in the manufacture of some pesticides that are less harmful to the environment.
• It is used for the production of silicone emulsion used in silicone masterbatch production. These silicone oils can be high molecular weight or low molecular weight. This generally varies according to the usage area and properties of the silicone masterbatch.
• In pharmaceutical products, silicone oil is used together with Titanium dioxide, corn starch, Beef Gelatin, and active substance in the manufacture of some capsules.
• It is used together with Liquid Paraffin (Paraffin Oil) in the oil phase in the production of roll-on deodorants.
• It is used for defoaming and stabilizing oils in the nuts industry.
• New usage is emerging in the manufacture of soft lithography in biomedical microelectromechanical systems.

What are the Factors Affecting Prices?

In terms of price, it is directly proportional to Dimethicone usage areas. As the usage area of Dimethicone increases, the price of Polydimethylsiloxane will increase.

Polydimethylsiloxane prices change depending on the production of this chemical substance. As its production increases, the price of Dimethicone will decrease.

Dimethicone (Polydimethylsiloxane) prices vary depending on the number and stocks of companies selling Dimethicone (Polydimethylsiloxane). Dimethicone (Polydimethylsiloxane) prices decrease as Dimethicone (Polydimethylsiloxane) stocks increase.