Emulsion - Emulsion

Also called an emulsion. A type of dispersion system in which one liquid is dispersed as tiny particles within another liquid. Milk is one example, in which oil is dispersed as tiny particles within water, so it is called an oil-in-water type emulsion. In contrast, a water-in-oil type emulsion is one in which water droplets are dispersed in oil or other organic liquids. Generally, emulsions are unstable, and in many cases the oil and water droplets combine and separate into two phases, but the dispersion can be maintained by adding a surfactant. Surfactants used for this purpose are called emulsifiers.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

エマルションともいう．分散系の一種で，液体中にほかの液体が微粒子として分散したもの．牛乳などはその一例で，これは水中に油が微粒子となって分散しているので，水中油滴型(oil in water type)エマルションという．これに対して，油，そのほかの有機液体中に水滴が分散したものを油中水滴型(water in oil type)エマルションという．一般に不安定で，油滴や水滴が合一して2相に分離するものが多いが，界面活性剤を添加しておくと分散状態が持続される．この目的に使用される界面活性剤のことを，乳化剤という．

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