Basics and Applications of Pickering Emulsion

Abstract

Pickering emulsion, which stabilizes by adsorbing fine particles to the oil-water interface, is a technology discovered over 100 years ago. Why has it not been used in cosmetic formulations, despite its unique emulsification properties, texture, and stability that differ from conventional surfactant-based emulsification methods? In this review, we explain the basic information you need to know to use it in cosmetics, including the basic emulsification mechanism, the key elements of its stabilization, the selection of the type of oil to control the contact angle, and the preparation method. We then describe L/A (Liquid-in-Air), a system in which droplets are dispersed in air, which is an area that can only be developed using Pickering emulsion. In the second half of the article, we also introduce a development example in which our company applied Pickering emulsion to a sunscreen. This sunscreen was developed as an O/W type sunscreen formulation by emulsifying an oil phase containing a UV absorber using silica, which is a common cosmetic ingredient. As a result, it has become possible to develop a sunscreen formulation that not only continues to protect the skin from UV rays and does not wash away even in the harsh environment of the ocean, but also has the revolutionary effect of using seawater to further enhance the sunscreen's UV protection function.