UNIHAVRE, FR 3038 CNRS, URCOM, Normandie Univ., Le Havre, 76600, France.
Int J Cosmet Sci. 2020 Apr;42(2):198-207. doi: 10.1111/ics.12604. Epub 2020 Mar 2.
The increasing interest for the Pickering emulsions is based on the possibility to replace classical emulsifiers by the solid particles. This approach is extremely attractive for the cosmetic field. But, the main difficulty is to obtain stable emulsions with appreciable skin feel. However, there is no information about the texture of such systems. The aim of this study is to formulate and describe the textural properties of cosmetic Pickering emulsions compared with conventional systems.
Three metal oxides were selected: titanium dioxide, zinc oxide and silicon dioxide, able to form stable and totally emulsified systems. A conventional emulsifier was used to formulate the emulsion of reference. Finally, the mixture of two emulsifying systems, combining both, surfactant and particles, was also studied. Then, a sensory panel was asked to quantify the intensities of the perception of the seven discriminating attributes.
Each particle brought its properties to the textural perception of the emulsion. TiO particles ensured the whitening effect of the emulsions, SiO provided the screech residue, whereas ZnO gave intermediate results. The conventional surfactant was perceived as glossy, greasy and more difficult to spread. The particle/surfactant mixtures gave mostly in-between results.
The study shows that the sensory profile of Pickering emulsions is indirectly and directly governed by the particle properties used for the emulsion stabilization: indirectly, through affecting the emulsion orientation (oil in water or water in oil), the droplet organization and viscosity, and directly, through the particle perception on the skin surface.
Pickering 乳液越来越受到关注，是因为可以用固体颗粒替代传统的乳化剂。这种方法在化妆品领域极具吸引力。但主要的困难是获得具有良好肤感的稳定乳液。然而，关于此类体系的质感尚无信息。本研究的目的是配制并描述与传统体系相比的化妆品 Pickering 乳液的质构特性。
选择三种金属氧化物：二氧化钛、氧化锌和二氧化硅，能够形成稳定的完全乳化体系。使用常规乳化剂来配制参考乳液。最后，还研究了结合表面活性剂和颗粒的两种乳化体系混合物。然后，感官小组被要求定量感知七个有区别属性的强度。
每种颗粒都为乳液的质感感知带来了自身的特性。TiO2 颗粒确保了乳液的增白效果，SiO2 提供了磨砂残留，而 ZnO 则给出了中等的结果。常规表面活性剂被感知为有光泽、油腻且更难涂抹。颗粒/表面活性剂混合物大多给出了中等结果。
研究表明，Pickering 乳液的感官特征是由用于乳液稳定的颗粒特性间接和直接控制的：通过影响乳液的定向（油包水或水包油）、液滴组织和粘度间接控制，通过颗粒在皮肤表面的感知直接控制。
