Colloids-Properties of a Colloid

Colloids can be understood as any substance consisting of particles that are considerably larger than atoms or molecules but are too small to be seen by the naked eye. The colloid particles are microscopic and cannot be observed without an electron microscope. A colloid is a mixture of two or more substances mixed together, but these are not combined chemically. The colloid has a wide range of differential properties where the behaviour change is observed with the dispersion medium.

This article talks about the properties of a colloid. You will find brief information on the concept of colloid in chemistry, a thorough explanation of the properties of a colloid, and other related topics.

What are Colloids?

Colloids can be defined as a mixture in which one or more than one substance/s are scattered as considerably large solid particles, liquid droplets, or gaseous medium. It can be said that colloids are a mixture of substances in which one substance is divided into minute particles that are also known as colloidal particles. 

They range from 1 to 1000 nm (nanometer) in diameter, which makes them easily visible when seen through an optical microscope, but there are also some of them which have to be seen through an ultramicroscope; therefore, when a beam of light is passed through a colloid the path of the light becomes visible, and hence it can be said that colloids do not settle down when they are left undisturbed.

A few examples of colloids are milk, cream, fog, smoke, cloud, blood, etc.

Considering all these examples, you would have understood that colloidal particles are stable.

Physical properties of Colloids

• Colloids are small enough to scatter a beam of light passing through it (Tyndall effect), making its path visible.

• A special process called configuration is used to separate colloidal particles, i.e., they can not be separated using the process of filtration.

• A colloid is a heterogeneous mixture.

• These are too small to be seen by the unaided eye.

• They do not settle down when they are left undisturbed.

• They are stable if the interaction energy due to attractive particles is less than kT (k- constant, T- absolute temperature).

• Some colloids are translucent in nature, and that is because of the Tyndall effect, while others can be opaque or have a bit of colour.

Electrical properties of Colloids

Electrophoresis – In this process, the electric field is applied to the colloidal solution, making colloidal particles’ movement possible. Based on the accumulation near the electrodes, the particle charge is predicted. In case the colloidal particles get collected around the negative electrode, the charges of the particle are positive, whereas, if the colloidal particles get collected around the positive electrode, the particle charges are negative. 

Electrical double-layer theory – According to the electrical double layer theory, the charge travels to the colloidal particles by placing ions so that they are further absorbed in immovable points. At the same time, the second layer has diffused mobile ions. Both the layers have equal charges. 

Electro-osmosis – In the process of electro-osmosis, the colloidal solution dispersing medium is influenced by the particles and the electric field. 

Optical properties of Colloids

According to Tyndall’s effect, it is a phenomenon where the light is scattered in different parts by the colloidal particles. The particles which are already present in the solution do absorb the light. After the light is absorbed completely, a part of the light is scattered in different directions. The results that come out lead to the Tyndall effect. 

Kinetic properties of Colloids

When the colloidal dispersion is observed under the microscope, it can be concluded that the particles are moving continuously. This zigzag movement in the colloidal solution is referred to as the Brownian effect. This movement occurs because of the molecule’s unique bombardment available in the dispersed medium. 

Conclusion

With this, we come to an end to the discussion about the properties of a colloid. A mixture in which one or more than one substance/s are scattered as considerably large solid particles, liquid droplets, or gaseous medium. A few examples of colloids are milk, cream, fog, smoke, cloud, blood, and so on. 

In this article describing the properties of a colloid mixture, we studied the concept of the properties of a colloid in length. We covered several other topics, such as introduction to colloid, properties of a Colloid, and other related topics in detail.