Michael Bevan
Johns Hopkins University, MD·Engineering
Almost no real surface is flat. Biological, geological and manufactured surfaces are curved, rough and often deformable, and that matters because coatings made of tiny particles behave differently depending on the shape of the surface beneath them.
- Fields
Engineering
Materials Science
Chemistry
- Topics
colloids
self-assembly
topological defects
- Grants
- 3 known grants, through Sep 2028
What they work on
- Measure and model how spherical and ellipsoidal colloidal particles interact on spherical, cylindrical and wavy surfaces as a function of particle aspect ratio, surface coverage and substrate curvature, using optical microscopy paired with simulation.
- Characterize the structures colloids form on curved surfaces, including spatial density variations, order-parameter profiles describing local alignment, and the type and arrangement of topological defects caused by geometric frustration.
- Quantify translational and rotational self-diffusion and defect dynamics on curved surfaces, testing whether particle motion becomes unusually heterogeneous near topological defects.
- Match high-dimensional particle-scale dynamic simulations to microscopy measurements of potentials and diffusivities in a model colloidal system with tunable interactions, to obtain accurate predictive dynamics.
- Develop coarse-grained models based on reaction coordinates, low-dimensional descriptors of assembly state, that give pathways and rates for stochastic microstructure evolution and topological defect relaxation on curved surfaces.
- Implement feedback control with optimal control policies that drive differently shaped particles into low-defect liquid-crystalline and crystalline target microstructures in minimum time on varying surface topographies.
- Measure and model the dipolar interactions of porous precursor particles in nonuniform AC electric fields to learn how material properties, size, shape and internal pore structure set particle position, orientation and packing on a support.
- Measure and model particle and defect dynamics of membrane precursor particles across liquid, liquid-crystal and crystal states, both at fixed electric field and during field-induced transitions between states.
- Apply optimal feedback control policies to assemble low-defect supported membranes from differently shaped porous precursor particles, testing whether electric-field control provides a material-agnostic fabrication route.
More about the research
When micrometer-scale particles (colloids) pack onto a curved surface, perfect ordering becomes geometrically impossible, so the arrangement is forced to contain topological defects: localized mismatches in the packing pattern. These defects change the optical, mechanical, thermal and porosity properties of the resulting coating. Across three projects the lab combines optical microscopy of real particles with computer simulation to work out how particle shape, inter-particle forces and surface curvature together determine what structures form, how fast they form, and how to steer them toward a desired arrangement in real time.
Why it matters
Particle coatings on curved surfaces underpin two- and three-dimensional printing, optical coatings, flexible electronics, energy capture and storage, and membranes for chemical separations, yet defects and material-specific recipes limit manufacturing. Learning how curvature and particle shape govern assembly, and adding real-time feedback control, could yield general, material-agnostic routes to low-defect films and membranes. The projects include classroom and laboratory outreach modules using microscopy and computational visuals for pre-college students in Baltimore.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Colloidal Interactions, Structure, and Dynamics on Curvature Landscapes
NSF · Oct 2025 – Sep 2028
Dynamic Pathways & Feedback Control of Topological Defects on Topographical Surfaces
NSF · Aug 2024 – Jul 2027
Feedback Controlled Assembly of Colloidal Precursors into Low-Defect Membranes
NSF · Jul 2024 – Jun 2027
Closest labs
Bhuvnesh Bharti
Louisiana State University, LA·Engineering·Early-career
Use large-scale simulations of coupled magnetic, hydrodynamic and contact interactions, plus analytical theory, to derive design rules for how micron-scale magnetic colloids aggregate and move cooperatively in porous media and open three-dimensional fluids.
Jonathan Rothstein
University of Massachusetts, MA·Engineering
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.
Sharon Glotzer
University of Michigan, MI·Materials Science
Develop MPATHS, system-agnostic software that identifies local structural motifs from particle positions and orientations and tracks them along phase transition pathways.
The school
Johns Hopkins University: 100 labs on PI Pages, $4.1B a year on research, 622 research doctorates a year.
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