Difference Between Antifoam and Defoamer

The key difference between antifoam and defoamer is that antifoam agents can prevent foam from forming, whereas defoamers can control the amount of existing foam.

Antifoam and defoamer are two ant-foaming agents that have different application depending on their mode of action and timing. There are many different types of antifoaming agents, such as silicone compounds, alcohol compounds, organic compounds, etc.

1. Overview and Key Difference
2. What is an Antifoam
3. What is a Defoamer
4. Side by Side Comparison –Antifoam vs Defoamer in Tabular Form
5. Summary

What is an Antifoam?

Antifoam is a chemical additive that can prevent the formation of foam. Generally, manufacturers use antifoam agents in their formulas if they anticipate the tendency for the formation of foam during its use. Antifoams are generally slightly soluble in foaming solutions, and they can cause a decrease in surface tension.

Figure 01: Polydimethylsiloxane, a Widely Used Antifoaming Agent

The most commonly used antifoams include silicone compounds and high boiling alcohols, including oleyl alcohol and octylphenoxyethanol. Typically, these compounds are added batch-wise when required. The batch dosage can range from 5 to 20 ppm. Moreover, these additives play an important role in increasing the washing effectiveness. This occurs by entrapping air from forming in the system that can allow easier and unrestricted flow of filtrate through the screens and washers.

What is a Defoamer?

Defoamer is an antifoaming agent that can control the existing foam in liquids that are useful in different industries. The defoamers can eliminate any existing foam in the liquid, but they cannot prevent the formation of new foam. The most common examples of defoamers include insoluble oils, polydimethylsiloxanes and some other silicone compounds, alcohols, stearates and glycols. We can name a defoamer as a chemical additive. This chemical additive is applied when we need to break a foam already formed.

Difference Between Antifoam and Defoamer

Figure 02: Action of Defoamer

Generally, these compounds are insoluble in the foaming medium and have surface-active properties. As a specific feature of defoamers, we can identify their low viscosity and the ability to spread rapidly on foamy surfaces. Moreover, defoamers have an affinity for air-liquid surface. They destabilize the foam lamellas. This destabilization causes the rupture of the air bubbles, and it can cause the breakdown of surface foam.

There are different types of defoamers, such as oil-based defoamers, powder defoamers, water-based defoamers, silicone-based defoamers, alkyl polyacrylates, and EO/PO based defoamers. Among them, oil-based defoamers are the most common additive type.

What is the Difference Between Antifoam and Defoamer?

Antifoams and defoamers are antifoaming agents we can use as chemical additives in industries. The key difference between antifoam and defoamer is that antifoam agents can prevent foam from forming, whereas defoamers can control the amount of existing foam. Therefore, antifoams reduce foam formation while defoamers reduce existing foam. Besides, silicone compounds and high boiling alcohols including oleyl alcohol and octylphenoxyethanol are examples of antifoams while oil-based defoamers, powder defoamers, water-based defoamers, silicone-based defoamers, alkyl polyacrylates, and EO/PO based defoamers are examples of defoamers.

The following infographic summarizes the difference between antifoam and defoamer in tabular form.

Summary – Antifoam vs Defoamer

Reference:

1. “Antifoams.” Overview | ScienceDirect Topics, Available here.
2. “Defoamer.” Wikipedia, Wikimedia Foundation, 27 Jan. 2021, Available here.

Image Courtesy:

1. “PmdsStructure” By Smokefoot – Own work (Public Domain) via Commons Wikimedia
1. “Antifoam” By Langbein Rise (talk) – I created this work entirely by myself. (Public Domain) via Commons Wikimedia