Mineralogy Lecture Series: Hy Si Bui

Description

Dr. Hy Si Bui, a senior principal scientist and head of transversal and physical chemistry of applied research at L'Oréal, will give a talk entitled "Rheology in Cosmetics -- How Material Science Allows Us to Develop Better Cosmetic Products" for the Department of Earth & Planetary Sciences.

Abstract:

Cosmetic products can be in anhydrous liquid form (e.g., liquid lipstick or lip gloss), or in oil-in-water (O/W) or water-in-oil (W/O) emulsion form as seen in liquid foundations, skincare products, sunscreen, and lotion. In addition, some products are also in gel form (e.g., hair styling gel or foundation gels). The cosmetic formulations contain many ingredients including polymers, surfactants, oils, water, pigments, and preservatives. Interactions between these ingredients play an important role in influencing stability, texture, performance, and sensory characteristics of the final products. Therefore, rheology is employed during various stages of product development, starting from the proof of technical concept to the sensory evaluations, in addition to addressing stability issues and other scale-up issues during manufacturing.

This talk will focus on the challenges in cosmetic science and the application of rheology to the field, illustrated through some examples in make-up and skin care by using the thermoplastic elastomer (TPE). From understanding the phase behavior of the TPE such as Styrene-Ethylene/Butylene-Styrene block copolymer associated with the other resin or copolymer, we are able to create many cosmetic products for consumers such as a lip gloss that can last for two to four hours or a skin tightening product that can reduce eye bag and wrinkle instantly.