Researchers from the Norwegian University of Science and Technology have developed a new method to control how drops of oil behave using electricity, which could have applications in the cosmetics industry.
Emulsifiers are used in many make-up products to keep the mixture stable and prevent separation, and the new study, published in the journal Nature Communications, shows how designing droplets of oil using electricity creates a technique that could be used for many applications, including cosmetics.
"We have conducted a very simple experiment to show that we can control particles on the surface of oil droplets using an electric field," explains Jon Otto Fossum, professor in the Department of Physics at the university.
Fossum and his team used micrometre-sized particles of clay and silicone oil droplets for their experiment.
First, the clay particles coated the droplet, but when the voltage was turned on, the clay particles made a ring around the drop.
By controlling the strength of the electrical voltage, researchers can control how the particles accumulate in the ring, much like the way your eye controls how much the pupil opens in response to light, says the research.
"It is also interesting that we have shown that we can use an electric voltage and environmentally friendly clay particles to control droplets, which means that we might be able to design these kinds of emulsions without adding chemicals,” continues Fossum.
“This could be important for applications where you want to avoid introducing foreign chemicals into the environment.”
"The physical or chemical control of emulsions is very important for many areas of technology and for many different applications," he ends.
Fossum says the next step is to expand understanding of what the experiment illustrates, and to perform more laboratory experiments with particles other than clay, and with other types of fluids.
At the same time, the researchers are exploring some of the ideas they have about how their technique can be applied.