It's easy to make bubbles, but try making hundreds of thousands of them a minute - all the same size.
Rice University engineers can do that and much more. Rice chemical and biomolecular engineer Sibani Lisa Biswal and lead author and graduate student Daniel Vecchiolla have created a microfluidic device that pumps out more than 15,000 microscopic bubbles a second and can be tuned to make them in one, two or three distinct sizes.
A sequence shows the progression of bidisperse foam generation in a microfluidic device created at Rice University. When bubbles enter, they pinch the preceding bubble into two before becoming a wall against which the next bubble will be pinched.
Credit: Biswal Lab/Rice University
The work featured on the cover of the Royal Society of Chemistry journal Soft Matter enables customizable, "wet" foams in small amounts for applications that include chemical and biological studies.
The best part is that the bubbles themselves do the hard part.
A movie that demonstrates the mechanism shows elongated bubbles shooting through a tube into an input channel. Each arrow-like bubble moves with enough force to split the bubble ahead of it, but the arrow remains intact.
It takes its place between the new "daughter" bubbles and becomes a "wall" that holds the next bubble in place for splitting. In that way, only every other bubble entering the expansion splits from the inter-bubble forces.
Vecchiolla described the process as "metronomic," the tick being a bubble splitting and the tock a bubble that remains whole.
When the input is centered and all the other parameters - the type of liquid, its viscosity, the flow rate and the width of the channel - are right, the device fills with large bubbles in the middle and two ranks of identical, smaller bubbles along the edges. When the input is offset, the stream produces bubbles in three sizes.
"There's interest in using monodisperse bubbles for material applications and miniaturized reactors, so there's been a lot of studies about the generation of uniformly sized gas bubbles," Biswal said. "But there have been very few that looked at using neighboring bubbles to create these daughter bubbles. We're able to generate well-ordered foam systems and control the size distribution."
Recent alumna Vidya Giri helped create the microfluidic channels, which are about one-twentieth of an inch wide with a feeder channel of about 70 microns.
Biswal is an associate professor of chemical and biomolecular engineering and of materials science and nanoengineering. The National Science Foundation supported the research.
Read the abstract at https:/
Foam favorable for oil extraction: http://news.
Clues to foam formation could help find oil: http://news.
Department of Chemical and Biomolecular Engineering: https:/
Department of Materials Science and NanoEngineering: https:/
George R. Brown School of Engineering: https:/
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,962 undergraduates and 3,027 graduate students, Rice's undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for lots of race/class interaction and No. 2 for quality of life by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl.
David Ruth | EurekAlert!
Carbon-loving materials designed to reduce industrial emissions
06.07.2020 | DOE/Oak Ridge National Laboratory
Thermophones offer new route to radically simplify array design, research shows
03.07.2020 | University of Exeter
Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.
Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....
Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.
Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...
A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...
Live event – July 1, 2020 - 11:00 to 11:45 (CET)
"Automation in Aerospace Industry @ Fraunhofer IFAM"
The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM l Stade is presenting its forward-looking R&D portfolio for the first time at...
With an X-ray experiment at the European Synchrotron ESRF in Grenoble (France), Empa researchers were able to demonstrate how well their real-time acoustic monitoring of laser weld seams works. With almost 90 percent reliability, they detected the formation of unwanted pores that impair the quality of weld seams. Thanks to a special evaluation method based on artificial intelligence (AI), the detection process is completed in just 70 milliseconds.
Laser welding is a process suitable for joining metals and thermoplastics. It has become particularly well established in highly automated production, for...
02.07.2020 | Event News
19.05.2020 | Event News
07.04.2020 | Event News
06.07.2020 | Health and Medicine
06.07.2020 | Social Sciences
06.07.2020 | Materials Sciences