Uniform-sized silicone oil microemulsions: Preparation, investigation of stability and deposition on hair surface

Emulsions are commonly used in foods, pharmaceuticals and home-personal-care products. For emulsion based products, it is highly desirable to control the droplet size distribution to improve storage stability, appearance and in-use property. We report preparation of uniform-sized silicone oil microemulsions with different droplets diameters (1.4–40.0 μm) using SPG membrane emulsification technique. These microemulsions were then added into model shampoos and conditioners to investigate the effects of size, uniformity, and storage stability on silicone oil deposition on hair surface. We observed much improved storage stability of uniform-sized microemulsions when the droplets diameter was ⩽22.7 μm. The uniform-sized microemulsion of 40.0 μm was less stable but still more stable than non-uniform sized microemulsions prepared by conventional homogenizer. The results clearly indicated that uniform-sized droplets enhanced the deposition of silicone oil on hair and deposition increased with decreasing droplet size. Hair switches washed with small uniform-sized droplets had lower values of coefficient of friction compared with those washed with larger uniform and non-uniform droplets. Moreover the addition of alginate thickener in the shampoos and conditioners further enhanced the deposition of silicone oil on hair. The good correlation between silicone oil droplets stability, deposition on hair and resultant friction of hair support that droplet size and uniformity are important factors for controlling the stability and deposition property of emulsion based products such as shampoo and conditioner.

Uniform-sized silicone oil microemulsions with different droplet diameters were successfully prepared using membrane emulsification technique in comparison with conventional homogenizer. Size and uniformity of silicone oil droplets have important influence on the deposition property of hair surface.Figure optionsDownload high-quality image (98 K)Download as PowerPoint slideHighlights
► ME technique is promising to prepare uniform-sized silicone oil emulsions.
► Droplet size and uniformity have important effect on silicone oil deposition on hair.
► Size distribution is vital to control emulsion stability, deposition and hair friction.
► Alginate plays a significant role to enhance the silicone oil deposition on hair.