Micellar water characterisation via laser light scattering

 The size and charge of the micelles may impact their performance and stability. This technology may provide a new way to easily characterise these formulations.

A popular facial cleanser on the cosmetic market right now is micellar water. Many companies carry this product and tout its ability to remove dirt, oil, and makeup while not irritating skin. As seen in Figure 1, micellar water is applied to a cotton pad and then wiped across facial skin to remove impurities. The main ingredients of the commercial cleanser are water, surfactant, and moisturiser, with fragrance often added.

When an aqueous solution has a certain amount of surfactant molecules, micelles are formed. The hydrophilic heads of the surfactant molecules orient themselves toward the water molecules while the hydrophobic tails orient towards each other, avoiding contact with water. These spherical aggregates are widely used in drug delivery, cosmetics, water treatment, detergents, and more. Characterisation of these micelles can help qualify their performance. One common way of characterising solutions like these is using non-invasive laser light scattering. This technique can be used to measure particle size, charge, and rheological properties. Currently, it is not clear whether a qualification or characterisation method of micellar water formulations has been established. The presence of micelles and the solution’s dilute nature makes it a candidate for characterisation by laser light scattering.