What is Emulsion? Types, Examples and Quiz


In the previous article on Emulsifiers, the concept of emulsion was highlighted on.

What is Emulsion?

Emulsion is definitely a common term in the chemistry world. Emulsion is the mixing or colliding of one liquid with another liquid the are normally insoluble in each other. It is a type of Colloid action. Although, the mixture of the two immiscible (insoluble) liquids will separate again after a period of time, unless an Emulsifier is added to it.

Emulsions can occur naturally, such as milk, which is an emulsion of fat globules dispersed in water. They can also be created intentionally for various industrial, scientific, and culinary applications. Emulsions are commonly used in food preparation, cosmetics, pharmaceuticals, and photography, among other fields.

To stabilize an emulsion and prevent the droplets from coalescing and separating, emulsifiers or surfactants are often added. Emulsifiers have both hydrophilic (water-attracting) and lipophilic (oil-attracting) properties, which allow them to adsorb at the interface between the oil and water, reducing the surface tension and providing stability to the emulsion.

Emulsions can have different properties depending on the ratio of the dispersed and continuous phases, the size of the droplets, and the nature of the substances involved. They can range from thin and fluid-like to thick and creamy, and their stability can vary from temporary to long-lasting.

Types of Emulsion

1) Water-in-Oil Emulsion: Here, the water is suspended in an oil mix. This emulsifier suitable for stabilizing this type of emulsion is more soluble in water and less soluble in oil. An Example is Ice cream, butter, ointments and so on. W/O emulsions are used when it is desirable to have an oil-based system with water droplets dispersed within it.

2) Oil-in-Water Emulsion: Here, the oil is suspended in water mix. This emulsifier suitable for stabilizing this type of emulsion is more soluble in oil and less soluble in water. An Example is Lotions, milk, mayonnaise, and so onO/W emulsions are typically used when it is desirable to have a water-based system with oil droplets dispersed within it.

water and gas

3) Multiple Emulsion: These emulsions involve the presence of both oil-in-water and water-in-oil droplets. They are denoted as either W/O/W (water-in-oil-in-water) or O/W/O (oil-in-water-in-oil) emulsions. Multiple emulsions are created by incorporating one emulsion into another using appropriate emulsifiers and techniques. They find applications in areas such as food, pharmaceuticals, and cosmetics.

4) Nanoemulsion: are emulsions with droplets that are extremely small, typically on the nanometer scale. They are thermodynamically stable and have a transparent or translucent appearance. Nanoemulsions have gained attention due to their enhanced stability, increased surface area, and potential for improved delivery of active ingredients in various industries, including pharmaceuticals, food, and cosmetics.

5) Pickering Emulsion: are stabilized by solid particles that adsorb at the oil-water interface, forming a protective layer. These solid particles can be inorganic materials like clays or organic compounds. Pickering emulsions are known for their robust stability and find applications in areas such as food science, cosmetics, and advanced materials


It's worth noting that emulsions can also be classified based on their viscosity, such as low-viscosity emulsions (e.g., salad dressings) and high-viscosity emulsions (e.g., creams and lotions). The specific type of emulsion formed depends on the formulation and the desired properties for a particular application.

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