Polymethylsilsesquioxane (PSQ) Separation in Serum Formula

Question

I have a stable serum formula and added Polymethylsilsesquioxane (PSQ) at 5%. However, I encountered separation issues:

When added to the water phase, the PSQ appears to separate and stay within the water part.
When added to the oil phase, white gel-like particles float on top, seemingly staying within the oil part.

How can I prevent this separation and ensure the Polymethylsilsesquioxane is properly dispersed in the formula?

MySkinRecipes Expert · Accepted Answer

Polymethylsilsesquioxane (PSQ) Dispersion Issue

You have a stable serum formula and are encountering separation when adding Polymethylsilsesquioxane (PSQ) at 5% to either the water or oil phase. When added to the water phase, the PSQ appears to separate and stay within the water part. When added to the oil phase, white gel-like particles float on top, seemingly staying within the oil part.

This issue likely occurs because your serum formula, being low in viscosity, lacks the necessary internal structure to properly suspend and hold the PSQ particles. PSQ is a powder that needs to be well-dispersed and supported within the formulation to prevent settling or separation.

While PSQ can be used in various cosmetic formulations, including serums, it requires a stable base with sufficient viscosity or a specific structure to keep the particles evenly distributed.

To address this, you can try the following methods, as suggested:

Increase Formula Viscosity with a Gel Maker: Add 0.5-0.7% of Pro Polymer to your current formula. Pro Polymer is a gel maker that creates a polymeric structure within the water phase, which can help suspend the PSQ particles and prevent them from separating. Mix the Pro Polymer into the water phase first to form a gel before incorporating other ingredients, especially if your formula contains electrolytes.
Convert to a Cream Texture: If a thicker gel is not desired, you can modify your formula to create a cream texture. Add 3-5% of Cetearyl Alcohol to your oil phase. Heat both the oil phase (containing Cetearyl Alcohol and other oil-soluble ingredients) and the water phase to 70°C separately. Then, combine the heated water phase into the heated oil phase while stirring, following your usual method for creating the serum base. The cream structure provided by Cetearyl Alcohol and the emulsifier (SiliSolve Plus) can help keep the PSQ dispersed.

Both approaches aim to provide a more robust structure to your formula, allowing the Polymethylsilsesquioxane particles to remain evenly suspended and prevent separation.