Recommended Emulsifier for Anhydrous Dimethicone and Oil Serum

To combine Dimethicone 1000 with natural oils or hydrocarbons in an anhydrous (water-free) system and prevent separation, you need a silicone-based compatibilizer that features an alkyl chain (like a Lauryl group). This alkyl chain allows the ingredient to bridge the gap between the silicone phase and the oil phase.

Based on your requirements and the ingredients available, here are the best recommendations:

1. The Best Compatibilizer: SiliSolve Plus™ (Lauryl PEG-9 Polydimethylsiloxyethyl Dimethicone)

This is the most effective choice for your anhydrous serum. Unlike standard silicone emulsifiers, the Lauryl modification makes it highly compatible with both silicones and various types of oils (vegetable oils, mineral oils, and esters).

• Function: It acts as a bridge to keep the Dimethicone and oils from separating.
• Usage Rate: 1-3% is typically sufficient for anhydrous systems.
• Advantage: It is an odorless, high-purity grade suitable for face and hair products.

2. The Stabilizer: Oil-Fix™ S (Silica Dimethyl Silylate)

In an anhydrous serum, separation often occurs because the ingredients have different densities and polarities. Adding a gelling agent can physically trap the droplets and prevent them from merging.

• Function: It thickens the silicone/oil blend into a gel or high-viscosity serum, which significantly improves long-term stability.
• Usage Rate: 0.5-2% for a slight thickening and stabilization; 3-5% for a thicker gel texture.
• Advantage: It also provides a "matte" finish and reduces the greasy feel of the oils.

3. Comparison with Previous Suggestions

• PEG/PPG-18/18 Dimethicone: This is primarily a Water-in-Silicone emulsifier. While it can help, it lacks the Lauryl (alkyl) group found in SiliSolve Plus™, making it less effective at bridging silicones with natural oils.
• Lauryl PEG-8 Dimethicone: While this has the necessary Lauryl group, it is specifically noted in the technical data to be incompatible with Dimethicone 100cSt and higher. Since you are using Dimethicone 1000, this ingredient is not recommended for your specific formula.

Recommended Formulation Strategy:

For a professional, stable anhydrous hair or face serum:

1. Main Phase: Mix your Dimethicone 1000 and other silicones.
2. Oil Phase: Mix your natural oils or esters.
3. Compatibility: Add 2-3% SiliSolve Plus™ to the silicone phase first, then slowly blend in the oil phase.
4. Stability Boost: If the texture is too thin or still shows signs of separation, add 1% Oil-Fix™ S to increase the viscosity and lock the mixture together.