Liquid Powder Sunscreen Formulation: Is an Emulsifier Needed?
Question
I want to formulate a liquid powder sunscreen that feels like water mixed with powder. The desired texture should be non-sticky and non-oily, leaving only powder residue on the skin.
The formulation will contain mineral sunscreens like Zinc oxide and Titanium dioxide, potentially along with Thanaka powder and Iron oxide.
I want to avoid using silicones.
For this type of liquid powder formulation (suspension), is it necessary to include an emulsifier?
Answer
Based on your goal of creating a liquid powder (แป้งน้ำ) formulation that feels like water mixed with powder, you generally do not need an emulsifier.
Here's why:
- A liquid powder is typically a suspension, where solid particles (like Zinc oxide, Titanium dioxide, Thanaka powder, Iron oxide) are dispersed in a liquid base (like water).
- You would shake the product well before each use to temporarily disperse the powders.
- Emulsifiers are used to create emulsions (like lotions or creams), which blend oil and water phases together into a stable mixture. This would result in a different texture than the simple water-powder feel you desire.
Your description of wanting a product that is "not sticky, not oily, with only powder residue on the skin" perfectly matches the characteristics of a non-emulsified liquid powder suspension.
As mentioned in the previous reply, dispersing high concentrations of mineral powders like Zinc oxide and Titanium dioxide without dispersants (often silicones or oils) can sometimes be challenging and might result in a slightly dry or difficult-to-spread texture. However, this approach aligns with your requirement to avoid silicones and achieve a simple, non-greasy feel.
Therefore, to achieve the desired liquid powder texture, you should not use an emulsifier.