受賞記事
小角中性子散乱・レオロジーによる構造解析を利用した化粧品用ナノサイズエマルション製剤の開発
2014 年 24 巻 2 号 p. 111-114
詳細
2014 年 24 巻 2 号 p. 111-114
A stable nanoemulsion consisting of nanometer-sized oil droplets in water having a self-standing capability was prepared by high-pressure emulsification. Rheological measurements show that the nanoemulsion has a high viscosity and a yield stress. Small-angle neutron scattering (SANS) revealed the presence of an ordered crystal-like lattice structure in addition to spherical domains with a diameter of ca. 30 nm. Nonfluidity of nanoemulsion is ascribed to crystal-like lattice structure of nanodroplets. A mixed solution of 2-hydroxyethyl cellulose and the nanoemulsion has shear-thickening behavior (shear-induced gelation). Real-time SANS measurements with a Couette geometry as a function of shear rate (Rheo-SANS) revealed that a possible mechanism of gelation was proposed from the viewpoint of shear-induced percolation transition. Furthermore, mixtures of the nanoemulsion and poly (acrylic acid) solutions were opaque and kept the same interdomain distance and high viscosity. We estimated that it had phase-separated structure between nanoemulsion phase and poly (acrylic acid) solution phase.
