Physicists develop new method for manipulating minuscule drops

April 16, 2014 by Joost Bruysters

Researchers from the University of Twente MESA+ research institute, the Foundation for Fundamental Research on Matter (FOM) and the Eindhoven University of Technology have, in cooperation with industrial partners ASML and Océ, developed a new method for manipulating minuscule drops. The fundamental research can be helpful in completely different fields: from minuscule laboratories on chips, to the semiconductor and oil industries. The research was published today in the leading scientific journal Nature Communications.

The researchers from the University of Twente Physics of Complex Fluids department are the global leader in the field of 'electrowetting'. This technology enables you to deform small and set them in motion by means of an external electric field. Electrowetting is useful in many fields, such as in lab-on-a-chip technology, optofluidics and display technology.

Marble run

In their research, published today, the researchers reversed the method. They show that you can also use the electric field to slow down drops or bring them to a complete halt.

In their experiments, the researchers let drops slide down over a highly water resistant, inclined surface. By locally applying an on the inclined plane, they succeeded in slowing down drops or even bringing them to a standstill (see film). Professor Frieder Mugele, who was involved in the research, compares the effect with a marble run: "On a marble run, marbles initially accelerate. If you make a small hole in the run, which is deep enough, and if there is sufficient friction, the marbles eventually come to a complete halt. In our research we do exactly the same thing. In this case, however, the small hole is not a physical hole, but a 'potential hole', generated by an adjustable voltage." The researchers developed a scientific model that accurately describes the observed drop behaviour.

Targeted manipulation

The new method allows scientists to very precisely manipulate small drops. This is ideal for microfluidic systems, such as labs-on-a-chip (small laboratories the size of a chip), applications of which include performing blood tests. This new method allows, for example, for separating drops containing a cancer cell from drops containing another cell. The advantage of the method is that it permits a large flow of drops, while you still remain able to accurately manipulate individual drops (see film), as the scientists demonstrated in an earlier publication this year in the journal Lab-on-a-Chip. In addition, the method can be used for a variety of applications ranging from cleaning chips in the semiconductor industry and conducting research into methods for extracting more oil from existing oil fields.

Explore further: Measuring speed in flying inkjet drops

Related Stories

Measuring speed in flying inkjet drops

March 13, 2014

Physicists from the FOM workgroup Physics of Fluids (MESA+) at the University of Twente and from Océ-Technologies have developed a method to measure detailed speed data in flying inkjet drops. Their research was recently ...

Exotic shapes for liquid drops have many applications

December 3, 2013

( —Oil and water don't mix, as any chemist or cook knows. Tom Russell, a polymer scientist from the University of Massachusetts who now holds a Visiting Faculty appointment with Berkeley Lab's Materials Sciences ...

A breakthrough in medical acoustics

January 27, 2014

Researchers at the University of Twente, Delft University of Technology (TU Delft) and Erasmus MC (University Medical Center Rotterdam) have achieved a breakthrough in the field of medical ultrasound. Ultrasound irradiation ...

Recommended for you

Toward mass-producible quantum computers

May 26, 2017

Quantum computers are experimental devices that offer large speedups on some computational problems. One promising approach to building them involves harnessing nanometer-scale atomic defects in diamond materials.

New technology could revolutionize 3-D printing

May 26, 2017

A technology originally developed to smooth out and pattern high-powered laser beams for the National Ignition Facility (NIF) can be used to 3-D print metal objects faster than ever before, according to a new study by Lawrence ...

Solving the riddle of the snow globe

May 25, 2017

If you've shaken a snow globe, you've enjoyed watching its tiny particles slowly sink to the bottom. But do all small objects drift the same way and at the same pace?


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.