The key difference between gel and emulsion is that a gel is a semisolid substance, whereas an emulsion is a liquid.
A gel and an emulsion are two different substances having closely similar properties. Although emulsions are liquid substances, sometimes we can find them as semisolid compounds if we are using it for topical application purposes.
CONTENTS
1. Overview and Key Difference
2. What is Gel
3. What is Emulsion
4. Side by Side Comparison – Gel vs Emulsion in Tabular Form
5. Summary
What is a Gel
A gel is a semisolid having properties ranging from soft and weak to hard and tough. We can define a gel as a dilute crosslinked system showing no flow properties in its steady state. It is a soft, solid-like material having two or more components, including a liquid component. Gels are mostly liquid by weight, but they behave as solid material due to the presence of 3D crosslinked structure. The formation of a gel is known as gelation.
Figure 1: Silica Gel
Gelation is the formation of a gel from a mixture of polymers. In this process, branched polymers cause the formation of linkages between branches. Gelation is a type of crosslinking, and it leads to the formation of a large polymer network.
During the gelation process, a single macroscopic molecule forms at some point, and we call this point as the gel point. At this point, the mixture loses its fluidity and viscosity and becomes very large. We can detect the gel point of a system easily via observing a sudden change in viscosity. After the completion of the formation of this infinite network material, we can call it a “gel”, and this gel does not dissolve in the solvent. However, the gel can undergo swelling.
What is Emulsion?
An emulsion is a fine dispersion of minute droplets of one liquid in another in which it is not soluble or miscible. We can describe an emulsion as a mixture of two liquids which are immiscible with each other. An emulsion is a type of colloid. We often tend to use the two terms emulsion and colloid interchangeably, but the term emulsion specifically explains the mixture of two liquids that form a colloid.
Figure 02: Paint is an Emulsion
Typically, an emulsion has two phases: a continuous phase and a discontinuous phase. In this two-phase system, the discontinuous phase distributes throughout the continuous phase. When the continuous phase is water, we can name the emulsion or the colloid as a hydrocolloid. The boundary between the two liquid in an emulsion is called the “interface”.
Furthermore, an emulsion has a cloudy appearance. This appearance is a result of the presence of a phase interface that can scatter a light beam which passes through the emulsion. When all the light rays are scattered equally, an emulsion appears as a white liquid.
What is the Difference Between Gel and Emulsion?
Gel and emulsion are two different chemical substances. The key difference between gel and emulsion is that a gel is a semisolid substance, whereas an emulsion is a liquid. However, we can find some emulsions in the semisolid state according to its application. Fruit jelly, gelatin mixture, ointments, etc. are some examples of gels while paint, butter, egg yolk, etc. are examples of emulsions.
Below infographic summarizes the differences between gel and emulsion.
Summary – Gel vs Emulsion
A gel and an emulsion are two different chemical substances. The key difference between gel and emulsion is that a gel is a semisolid substance, whereas an emulsion is a liquid. However, sometimes we can find some emulsions in the semisolid state according to its application.
Reference:
1. Helmenstine, Anne Marie. “Emulsion Definition and Examples.” ThoughtCo, Feb. 11, 2020, Available here.
Image Courtesy:
1. “Silica gel” By KENPEI – KENPEI's photo (CC BY-SA 3.0) via Commons Wikimedia
2. “Download Wall Painting Paint A Wall Free Photo” (CC0) via Needpix.com