Molecular Defoamers – A new age Technology

Molecular defoamers are growing field that are finding applications in many industrial processes. The use of conventional surfactants and defoamers in Industries can often create an undesirable side effect, which requires the other to sort out. Molecular defoamers represent a novel class of defoamers that break foam on a molecular level, which is unlike conventional defoamers that utilize macroscopic physical process. This is accomplished by the ability of the molecular defoamers to adsorb at the air-water interface of a foam bubble and, thereby, displace some of the surfactants that stabilize the foam. Based on a fundamental understanding of the effects of basic adsorption parameters, innovative molecular defoamers were developed that provide long term foam control; effectively reduce both surface tension and foam in a variety of emulsion polymers and decrease significantly the level of defects in Industrial applications.

To control the Foam:

Kill it (Defoam) Avoid it (Antifoam)

Defoamers – Chemicals or formulated products that destroy, or knock down, foam that has already formed. Defoamers, except in relatively large amounts, don’t prevent foam from forming.

Antifoams – Chemicals or formulated products that prevent the formation of foam. When discussing these materials, it is important to notice at what point in the process they are used. There are other factors you should consider as well.

SILICONE DEFOAMERS

A highly effective class of defoamers is obtained by combining dimethylpolysiloxanes with hydrophobic and partially hydrophilic polyethers.

The Silicone technique to defoam:

The silicone active ingredient displace surfactant molecules and thin out the lamellae leading to destable and collapse. Silica particles are transported by siloxanes onto the foam lamellae has an additional destabilizing effect on the foam. The Foam bubble bursts and the entrapped air escapes.

Silicone defoamer competitive features:

It gives better efficiency/cost compared to organic antifoams. Low surface tension Insoluble in the foaming medium Good spreading coefficient They are highly efficient and are therefore often more economical to use than organic defoamers. They control almost all types of foam encountered in any effluent. They are chemically inert and therefore resistant to chemical attack. They are thermo stable. They make for safe operating conditions. As they do not produce any undesirable degradation products, they are environmentally compatible.

MOLECULAR DEFOAMERS

Little bit of alterations have proven to provide good surfactant properties (both dynamic and equilibrium surface tension reduction) with low foam tendency, there is still a need for more efficient defoamers that can provide surfactant-like wetting performance to reduce or eliminate the tendency to cause coating defects that are often created by silicone defoamers. One class of defoamers that offers the potential for improved performance are the molecular defoamers. Unlike conventional defoamers, which utilize macroscopic physical process within the coating formulation, molecular defoamers break foam on a molecular level by adsorbing at the Liquid/Gas interface of foam bubbles and, thereby, displacing some of the foam-stabilizing surfactants with surfactants that behave otherwise. The adsorbed molecular defoamer molecules disrupt the foam stabilizing mechanisms that are imparted by the conventional surfactants adsorbed at the bubble Liquid/Gas surface, and thus allow liquid drainage to proceed until the bubble collapses.

CONCLUSIONS

Molecular defoamers represent a new age defoamers that break foam on a molecular level rather than by macroscopic physical process like conventional defoamers. This is accomplished by the ability of the molecular defoamers to adsorb at the Liquid/Gas interface of a foam bubble and, thereby, displace some of the surfactants that stabilize the foam. Based on this fundamental understanding, innovative molecular defoamers were developed foam control long term ability, a combination of low surface tension and low foam in a variety of application with very negligible level. The surface activity (low equilibrium and dynamic surface tension) of these molecules allows them to serve a dual function as wetting agents and defoamers in the systems.

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