Choosing Trimethylsiloxysilicate for Water-Based Liquid Eyeshadow Formulation

To formulate a liquid eyeshadow similar to the Sisley Paris Ombre Eclat Liquide, which is known for its lightweight, fresh, and long-wearing "second-skin" texture, the choice of film formers and stabilizers is critical.

1. Choosing the Right Trimethylsiloxysilicate (TMS)

For a mainly water-based product applied to the delicate eyelid area, you should use Silicone Film (Comfort-Wear, Hard, Isododecane Base).

• Why this version? While "Very Long-Wear" versions provide maximum durability, they can feel tight or "crack" on the moving eyelid. The Comfort-Wear version (Trimethylsiloxysilicate dissolved in Isododecane) provides a balance of excellent water resistance and a lightweight feel that remains comfortable throughout the day.
• Compatibility: Since your formula already contains Isododecane, this liquid version will integrate seamlessly into your Phase B (Oil Phase) before being emulsified into the water gel.

2. Recommended Ingredients for Your Formula

Based on your provided list, here are the specific components that match the high-performance profile of luxury liquid eyeshadows:

• Base & Thickener: Sepimax Zen (Polyacrylate Crosspolymer-6) is the perfect choice. It is highly stable with pigments and provides that "fresh" water-break feel upon application. Note that 2% will create a relatively thick cream-gel; for a more fluid "liquid" feel, you might experiment with 1.0–1.5%.
• Secondary Film Former: Vinyl Film (Medium Wear, Soft) (VP/Hexadecene Copolymer). This is essential for dispersing the high load of pearls/pigments and ensuring the color stays smooth and even without settling into fine lines.
• Texture Enhancers:
  • AminoSilk™ (Lauroyl Lysine): Adds a silky, "expensive" slip and improves the adhesion of the powders to the skin.
  • WhiteMatte3™ (Boron Nitride): Provides a soft-focus effect and helps the formula glide on smoothly.
• Pearls & Fillers:
  • Synthetic Fluorphlogopite (9 Micron & 20 Micron, Silane Coated): Silane coating is superior for water-based formulas because it makes the pearls hydrophobic, helping them stay suspended in the gel and adhere better to the skin for a "no-crease" finish.
  • MatteSilica 10™ (Silica Microspheres): Helps with oil absorption and provides a smooth, non-sticky finish.
• Solvent & Antioxidant: Use Isododecane (Germany) as your volatile carrier and Vitamin E (Tocopheryl Acetate) to protect the formula and skin.

3. Formulation & Mixing Insight

To achieve the Sisley-like texture:

1. Phase A (Water Phase): Hydrate the Sepimax Zen in the water/glycol mix until a clear, smooth gel forms.
2. Phase B (Oil/Film Phase): Mix the Silicone Film (TMS), Vinyl Film, and Isododecane. Then, disperse the Lauroyl Lysine and Boron Nitride into this oil phase.
3. Phase C (Pigment Phase): Add your silane-coated pearls and iron oxides. It is often best to disperse these into the Oil Phase (Phase B) first to ensure every particle is "wetted" by the film formers before introducing them to the water gel.
4. Emulsification: Slowly add the combined Phase B/C into Phase A while mixing with high shear. The Sepimax Zen will trap the oil droplets and pigments in its network, creating a stable, long-wearing liquid eyeshadow.

For the preservative, ensure you use a broad-spectrum system compatible with high-pigment loads.