Physics of fluids and active matter at interfaces


We are an interdisciplinary research group interested in understanding active matter systems at interfaces.

The group focuses on investigating the fundamental physics behind intriguing phenomena observed in soft matter, such as polymer solutions, and
active matter, such as bacteria suspensions.

The following subjects are relevant to the problems we like to think about
low Reynolds number fluid mechanics • Physics of living systems • environmental science • rheology • colloid science • coral reef restoration • bioremediation

We are part of the Mechanical Science and Engineering Department in the Grainger College of Engineering at the University of Illinois.

We thank the Oil Spill Recovery Institute for funding
>>> Biodegradation and transport of oil droplets

We thank the National Science Foundation for funding
>>> Collaborative Research: ECO-CBET: From Molecules to Sustainable Reef Platforms: Engineering Ecosystems for Coral Recruitment and Survival
>>> Convergence: RAISE: Engineering Coral Reef Recovery


We are a highly interdisciplinary research team with interests in the field of soft matter. Examples of soft matter include colloidal suspensions, polymer solutions, foams, granular materials, and biological materials. These materials are "soft" in the sense that they are deformed by thermal or mechanical stresses that are comparable to thermal fluctuations at room temperature.

We implement the tools of microfluidics, microscopy, high-speed imaging, and quantitative image analysis to experimentally study problems that lie at the interface of low-Reynolds numbers fluid mechanics, biophysics, and environmental science.

Our approach spans orders of magnitude in length, from single molecules to single cells to the environment, and time. We use observations in controlled fluid environments in combination with quantitative image analysis to understand physical mechanisms and chemical processes that we use to build mathematical models and predictive frameworks.

See below for a sample of ongoing and open projects in the lab.

  • Portfolio Item

    Oil degradation by marine bacteria

    How do single bacteria rid the oceans of hydrocarbon pollution?
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    Complex fluids and polymer physics

    How do single molecules driven far-from-equilibrium affect material properties such as viscoelasticity?
  • Portfolio Item

    Oil degradation in porous media

    How do physically and chemically heterogeneous microenvironments affect hydrocarbon degradation by bacteria?
  • Portfolio Item

    Cell growth at fluid interfaces

    What is life like when trapped in two dimensions?
  • Portfolio Item

    Particle tracking and microrheology

    How small of a sample is needed to determine its material properties?
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    Microfluidics and imaging techniques

    What new phenomena can we observe using the latest technologies?

Want to learn more?

We are always available and happy to discuss our research interests. Come visit the lab!

Meet The Team

''Més que un club''
Member Photo
Gabriel Juarez
Principal Investigator
Member Photo
Koumudhi Deshpande
Grad, ME PhD
Topic: Electro-inertial flows
Member Photo
Daniel Gysbers
Grad, Phys PhD
Topic: Larval settlement
Member Photo
Blake Langeslay
Grad, Phys PhD
Topic: Active nematics


  • Mark A. Levenstein (Postdoc; Larval settlement)

  • Giridar Vishwanathan (PhD; Inertial oscillatory flows)

  • Vincent Hickl (PhD; Microbial oil biodegradation)

  • Sameh Kattom (Undergraduate, Larval settlement)

  • Hima Pamu (Undergraduate, Microbial oil biodegradation)

  • Will Fahy (Undergraduate, Active nematics)

  • Interested in joining?

    We are always interested in recruiting creative and highly motivated individuals (Postdoc, graduate, and undergraduate) looking to conduct high-impact research with us.

    Unfortunately, there are no openings at this time. Please check back later for updates. Do not contact the PI regarding openings.

    Journal articles

    under review and published

    1. Stress and Alignment Response to Curved Obstacles in Growing Bacterial Monolayers
      B. Langeslay, W. Fahy, and G. Juarez
      Physical Review E, 109, 054608, (2024)

    2. Synchronous oscillatory electro-inertial focusing for microparticle manipulation
      G. Vishwanathan and G. Juarez
      Biomicrofluidics, 17, 064105 (2023)

    3. Coral larval settlement induction using tissue-associated and exuded coralline algae metabolites and the identification of putative chemical cues
      Z. A. Quinlan, M. Bennett, M. G. I. Arts, M. Levenstein, D. Flores, H. M. Tholen, L. Tichy, G. Juarez, A. F. Haas, V. F. Chamberland, K. R. W. Latijnhouwers, M. J. A. Vermeij, A. J. Wagoner Johnson, K. L. Marhaver and L. W. Kelly
      Proceedings of the Royal Society B, 290, 20231476 (2023)

    4. Hydrodynamic Treadmill Reveals Reduced Rising Speeds of Oil Droplets Deformed by Marine Bacteria
      V. Hickl, H. H. Pamu, and G. Juarez
      Environmental Science and Technology, 57, 37, 14082–14089 (2023)

    5. Microdomains and stress distributions in bacterial monolayers on curved substrates
      B. Langeslay and G. Juarez
      Soft Matter, 19, 3605-3613 (2023)

    6. Understanding the aggregation and flow response of donor-acceptor conjugated polymers
      J. J. Kwok, G. Vishwanathan, K. S. Park, B. B. Patel, D. Zhao, G. Juarez, and Y. Diao
      Macromolecules, 55, 10153-10166 (2022)

    7. Tubulation and dispersion of oil by bacterial growth on droplets
      V. Hickl and G. Juarez
      Soft Matter, 18, 7217-7228 (2022)

    8. Millimeter-scale topography facilitates coral larval settlement in wave-driven oscillatory flow
      M. A. Levenstein, D. J. Gysbers, K. L. Marhaver, S. Kattom, Z. A. Quinlan, H. M. Tholen, L. Tichy, L. W. Kelley, M. A. Vermeij, A. J. Wagoner Johnson, and G. Juarez
      PLoS ONE, 17, e0274088 (2022)

    9. Multicurvature viscous streaming: flow topology and particle manipulation
      Y. Bhosale, G. Vishwanathan, G. Upadhyay, T. Parthasarathy, G. Juarez, and M. Gazzola
      Proceedings of the National Academy of Sciences, 119, e2120538119 (2022)

    10. Effect of dispersants on bacterial colonization of oil droplets: a microfluidic approach
      V. Hickl and G. Juarez
      Marine Pollution Bulletin, 178, 113645 (2022)

    11. Hyperactivation is Sufficient to Release Porcine Sperm from Immobilized Oviduct Glycans
      M. Sharif, V. Hickl, G. Juarez, X. Di, K. Kerns, P. Sutovsky, N. Bovin, and D. J. Miller
      Scientific Reports, 12, 6446 (2022)

    12. A tradeoff between physical encounters and consumption determines an optimal droplet size for degradation
      V. I. Fernandez, R. Stocker, and G. Juarez
      Scientific Reports, 12, 4734 (2022)

    13. Composite Substrates Reveal Inorganic Material Cues for Coral Larval Settlement
      M. A. Levenstein, K. L. Marhaver, Z. A. Quinlan, H. M. Tholen, L. Tichy, J. Yus, I. Lightcap, L. W. Kelley, G. Juarez, M. J. A. Vermeij and A. J. Wagoner Johnson
      ACS Sustainable Chemistry and Engineering, 10, 12, 3960-3971 (2022)

    14. Assembly and characterization of an external driver for the generation of sub-kilohertz oscillatory flows in microchannels
      G. Vishwanathan and G. Juarez
      Journal of Visualized Experiments (179), e63294 (2022)

    15. Inertial focusing in planar pulsatile flows
      G. Vishwanathan and G. Juarez
      Journal of Fluid Mechanics, 921, R1 (2021)

    16. Generation and application of sub-kilohertz oscillatory flows in microchannels
      G. Vishwanathan and G. Juarez
      Microfluidics Nanofluidics, 24, 69 (2020)

    17. Steady streaming flows in viscoelastic liquids
      G. Vishwanathan and G. Juarez
      Journal of non-Newtonian Fluid Mechanics, 271, 104143 (2019)

    18. Steady streaming viscometry of Newtonian liquids in microfluidic devices
      G. Vishwanathan and G. Juarez
      Physics of Fluids, 31, 041701 (2019)

    19. Modeling the impact of dilution on the microbial degradation time of dispersed oil in marine environments
      V. I. Fernandez, R. Stocker, and G. Juarez
      Oilfield Microbiology, CRC Press, 215-232, (2019)

    20. Designing engineering tasks for collaborative problem solving
      S. Shehab, E. Mercier, M. Kersh, G. Juarez, and H. Zhao
      12th International Conference on Computer Supported Learning, 2, 825-826 (2017)

    21. Regular and irregular splashing of drops on geometric targets
      G. Juarez, T. Gastopoulos, Y. Zhang, M. L. Siegel, and P. E. Arratia
      Physics of Fluids, 24, 091105 (2012)

    22. Splash control of drop impacts with small geometric targets
      G. Juarez, T. Gastopoulos, Y. Zhang, M. L. Siegel, and P. E. Arratia
      Physical Review E, 85, 026319 (2012)

    23. Mixing by cutting and shuffling 3D granular flow in spherical tumblers
      G. Juarez, I. C. Christov, J. M. Ottino, and R. M. Lueptow
      Chemical Engineering Science, 73, 195-207 (2012)

    24. Extensional rheology of DNA suspensions in microfluidic devices
      G. Juarez and P. E. Arratia
      Soft Matter, 7, 9444 (2011)

    25. Transition to centrifuging granular flow in rotating tumblers: a modified Froude number
      G. Juarez, P. Chen, and R. M. Lueptow
      New Journal of Physics, 13, 053055 (2011)

    26. Motility of small nematodes in wet granular media
      G. Juarez, K. Lu, J. Sznitman, and P. E. Arratia
      Europhysics Letters, 92, 44002 (2010)

    27. Mixing by cutting and shuffling
      G. Juarez, R. M. Lueptow, J. M. Ottino, R. Sturman, and S. Wiggins
      Europhysics Letters, 91, 20003 (2010)

    28. Granular coarsening: Phase space and evolution analogies
      G. Juarez, R. M. Lueptow, and J. M. Ottino
      Physical Review E, 81, 012301 (2010)

    29. Axial band scaling for bidisperse mixtures in granular tumblers
      G. Juarez, J. M. Ottino, and R. M. Lueptow
      Physical Review E, 78, 031306 (2008)

    Image and video gallery