Why UoM chemists are all in a lather
Research impact and institutes 16th January 2020
No head on your beer? No froth on your coffee? No bubble in your bath? It may not be earth-shatteringly awful when it happens, but it sure is disappointing.
Luckily, researchers at The University of Manchester have made a breakthrough that could help bartenders make the perfect head of beer that lasts all the way to the end of your pint – just in time for Dry January! Oh…
Foam-mo
Foams are vital to a whole range of products and applications. It’s not just foam party promoters and bubble bath manufacturers who get in a lather about delivering good lather.
In fact, foam can play an integral role in extinguishing fires, cleaning up oil spills, filling cavities and unblocking drains. And of course, it’s also an important ingredient in a much-needed cappuccino at the start of the day and a relaxing bubble bath (or pint) at the end of the day.
Foams created by liquids that contain a single additive – a substance added to something in order to produce a specific effect, such as preservation – are relatively simple, which means their behaviour is easily understood and predictable.
However, where two or more additives are included, the waters become a little murkier. Thankfully, a team of chemists at The University of Manchester have made an important breakthrough in this understanding.
When does the bubble burst?
“For decades scientists have tried to get a handle on how to control reliably the lifetime and stability of foams made from liquids that contain mixed additives,” says Dr Richard Campbell – Lead Researcher of the study, which was published last month in the journal Chemical Communications.
“While the behaviour of foams made up with just one additive is quite well understood, as soon as mixtures like those used in products were studied, the results from research studies failed to paint a consistent picture,” he explains. “This is important, as some products benefit from foams that are ultra-stable and others from foams that are very unstable.”
The team devised a structural approach that rationalised the foam film stability of polyelectrolyte/surfactant mixtures using neutron reflectivity data. This gave them a new insight into the behaviour of the foams – namely that the “provision of electrostatic or steric stabilization in thin foam films is related to the spatial distributions of molecules interacting from opposing air/water interfaces”.
In layman’s terms, the team found they were able to relate the stability of the foam’s film to the surface arrangement of the additives – the liquid coating of the air bubble that prevents it from bursting.
Bring the bubbly
This insight could help product manufacturers mould and modify chemical elements in order to create exactly the right kind of foam – or lack of. For example, it could allow manufacturers to design washing detergents that do not produce excess foam – as the foam can prevent the clothes being cleaned properly.
“It was only through our use of neutrons at a world-leading facility [the Institut Laue-Langevin in France] that it was possible to make this advance, because only this measurement technique could tell us how the different additives arrange themselves at the liquid surface to provide foam film stability,” Dr Campbell explains.
The researchers now hope the insight will assist in the development of new products that have impact in the field of materials science, and that benefit the environment.
Someone pass us the bubbly!
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Words – Hayley Cox
Images – Endre Majoros, Steve Parker, Martin Abegglen, Jennifer Morrow
Chemistrymaterials scienceMaterials Science and Textilesresearch impact
