While some people may like foam on beer, liquid foaming is considered problematic in many areas,media reported. In industrial production, for example, unwanted foam slots up machines and takes up space that would otherwise be better utilized, or when foam forms in a bioreactor for cell growth, it can destroy or kill cells.
Now, a new material designed by the Massachusetts Institute of Technology (MIT) may be able to alleviate such a problem.
In general, in order to reduce foam formation, people will add alcohol to the liquid. However, these chemicals then have to be filtered out, adding cost and complexity. In addition, they may alter the chemical composition of the finished product.
Given these limitations, the team, led by Professor Kripa Varanasi, first watched a slow-motion video in which bubbles rise from the liquid, accumulating and forming foam on an immersed surface. In addition, the scientists note that each bubble initially bounces off the surface several times and eventually floats and settles around it.
This allowed researchers to create what they called a “gas-obsessed” surface. Just as hydrophilic surfaces attract water, gas-loving surfaces attract and diffuse bubbles.
It is understood that the surface of mIT is composed of three layers, each layer of texture is more fine than the previous layer, this structure is called shield, it allows a thin layer of air to maintain on the surface. As a result, when bubbles rise and hit the surface, they quickly spread and dissipate rather than bounce repeatedly. This means that they cannot accumulate on the surface, so there are very few bubbles to form.
In laboratory tests, two sheets of paper were placed in beakers filled with foamy liquid — one of which was coated with a gas-loving surface and the other was not. The result is that on unprocessed paper, the “bounce time” of the bubble is a few hundred milliseconds, while on the treated paper the number is reduced to only a few milliseconds. This difference results in the formation of a complete layer of foam on untreated materials, which are almost non-existent on gas-breathing materials.
The technology is said to be ready to be commercialised and requires little further improvement. The study was published in Advanced Materials Interfaces.