Researchers from the Georgia Institute of Technology have developed a new type of foam that could benefit a large number of industries ranging from automobiles to airplanes.
The new foam, called the capillary foam shows for the first time that the combined presence of particles and a small amount of oil in water-based foams can lead to exceptional foam stability when neither the particles nor the oil can stabilize the foams alone.
“It’s very difficult to stabilize foams, and we want foams that are stable for months or years,” said Sven Behrens, study co-author and professor at Georgia Tech’s School of Chemical & Biomolecular Engineering. “We’ve developed a way to make foams that is much easier and more broadly applicable than what is traditionally used.”
There are two traditional ways of stabilizing foam using additives with specific set of properties. In the first method, Surfactants, which are similar to detergents, are added to stabilize foams and the second method uses microscopic particles as additives for example talc powder.
The new study shows how particles with general properties can be used along with a little amount of oil.
“It sounds like we’re making the system more complicated by adding oil to the mix, but it’s a small amount of oil that could be something as simple as vegetable oil,” said Carson Meredith professor in the School of Chemical & Biomolecular Engineering.
The combined action of oil and particles stabilizes the air bubbles in the new foam. This synergy of oil and particulate is counterintuitive because oils usually decrease foam stability and are commonly used as defoaming agents. But just like the water-bridged grains of sand that hold a sand castle together, particles in the capillary foam form a stabilizing network connected by oil bridges.
“This is a novel phenomenon that people haven’t discussed before, so we need to know more about why this works,” Meredith said.
“We’re looking at several different application areas where it could be used as a product,” Behrens said in conclusion.
Image courtesy of Gary Meek