Viscosity Loss in Facial Cleanser with Phenoxyethanol and Salt

Hello,

Thank you for sharing your facial cleanser formula and the issue you encountered.

It's common for Phenoxyethanol to reduce the viscosity of surfactant-based formulations, especially those thickened with salt. This happens because Phenoxyethanol can interfere with the structure (like micelles or liquid crystalline phases) that the surfactants and salt form to create viscosity.

The staff's suggestion to pre-mix Phenoxyethanol with water before adding it to the main mixture is a good approach. This dilutes the Phenoxyethanol and allows it to be incorporated more gently into the surfactant system, minimizing disruption.

Here's how you can apply the staff's suggestion:

1. Combine the 84% water and the 1% Phenoxyethanol from your formula.
2. Mix well until the Phenoxyethanol is completely dissolved in the water.
3. Use this water/Phenoxyethanol mixture as your liquid base. Add the BabyFoam (10%), AminoWash (5%), and Lactic Acid (to adjust pH) as per your formula.
4. After adding these ingredients, gradually add the salt ("เล็กน้อยเพื่อให้หนืด") while stirring. Since Phenoxyethanol is now present from the beginning, the amount of salt required to achieve the desired viscosity might be different than before. You may need to experiment to find the optimal amount.
5. Ensure the pH is adjusted to your desired range after all ingredients are added.

By incorporating Phenoxyethanol earlier and in a diluted form, you may be able to maintain the viscosity better. Adjusting the salt level after adding all ingredients is key to optimizing the thickening in this type of surfactant system.

I hope this helps!