Jonathan Rothstein
University of Massachusetts, MA·Engineering
Some water-walking insects and bacterial swarms move across a liquid surface by releasing chemicals that change the surface tension, the 'skin' on the water. The surface pulls more strongly on one side than the other, and the object is pushed forward.
- Fields
Engineering
Physics
- Topics
Marangoni propulsion
Marangoni surfing
surface tension
- Grants
- 1 known grant, through Jul 2027
What they work on
- Measure how self-propelled Marangoni surfers move on levitating spherical water drops in microgravity aboard the International Space Station, focusing on how the drop's overall curvature changes their propulsion.
- Separate the effects of overall drop curvature from the gravity-induced bending of the surface around each particle by comparing ISS experiments with ground-based measurements.
- Build a combined computational and experimental framework that links particle motion, the transport of chemicals the surfers release, and interface curvature and confinement.
- Study how groups of Marangoni surfers interact, assemble and disassemble on curved interfaces, to inform the design of surfers and of self-assembly processes.
More about the research
This is called Marangoni surfing. Engineers have built small surfers that use the same trick for environmental sensing, for moving fluids in tiny channels, and for self-assembly at interfaces. Little is known about how these surfers behave on curved surfaces, such as the outside of a droplet. On Earth, gravity makes large spherical interfaces hard to create, so this question is difficult to study there.
Why it matters
Design rules for surfers that propel themselves along curved interfaces could support advances in small-scale robotics and microfluidics. A better understanding of self-assembly could help speed up the production of small structured materials. The project may also clarify how antibiotic-resistant bacteria colonize and survive at fluid interfaces, which could suggest new strategies against infectious disease.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Harishankar Manikantan
University of California-Davis, CA·Engineering·Early-career
Use asymptotic theory to calculate hydrodynamic interactions between pairs of particles in realistic non-Newtonian interfaces, including membranes and monolayers whose resistance to flow changes with deformation.
Kenneth Kamrin
University of California-Berkeley, CA·Engineering
Test whether dense granular flows depend strongly on gravity magnitude by running rotating drum experiments aboard the International Space Station using the Multi-use Variable-gravity Platform centrifuge, spanning near-weightlessness to above Earth gravity.
Chris Roh
Cornell University, NY·Engineering·Early-career
Compare the fluid dynamics of whirligig beetle propulsion at the water surface and in deep water through experiments, to see how surface tension changes how they swim.
The school
University of Massachusetts: 28 labs on PI Pages, $282M a year on research, 337 research doctorates a year.
Reach out
A start for your email. Fill in the brackets.