Fumed Silica as a Thickener in Clear Gel Sunscreen

Based on your interest in Arosil and its use as a thickener in a clear gel sunscreen, here is some general information about fumed silica:

Fumed silica is a common ingredient used to thicken and modify the flow properties (rheology) of cosmetic formulations.

Hydrophilic vs. Hydrophobic Fumed Silica

The main difference between different grades of fumed silica lies in their surface treatment:

• Hydrophilic Fumed Silica: This type has a surface that attracts water. It is typically used to thicken and stabilize water-based systems.
• Hydrophobic Fumed Silica: This type has been chemically treated to repel water and is more compatible with oils, silicones, and organic solvents. It is used to thicken non-polar systems.

Using Fumed Silica in Clear Gel Sunscreen

For a clear gel sunscreen, the suitability of fumed silica depends on the base of your gel:

• If your gel is primarily water-based, you would generally use a hydrophilic fumed silica as the thickener.
• If your gel is based on oils or silicones, a hydrophobic fumed silica would be more appropriate.

Achieving a truly clear gel with fumed silica requires excellent dispersion of the powder into the liquid phase to avoid visible particles or cloudiness.

Since specific "Arosil" products were not found in the database, please refer to the technical data sheet of the specific fumed silica product you have to determine if it is hydrophilic or hydrophobic and its recommended applications.