Datta Lab  |  Soft Materials in Complex Environments
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The milk we drink in the morning (a colloidal dispersion), the gel we put into our hair (a polymer solution), and the plaque that we try to scrub off our teeth (a biofilm) are all familiar examples of soft materials. Such materials also hold great promise in helping to solve engineering challenges like water remediation, oil recovery, carbon sequestration, and drug delivery.

As a field, we have made tremendous progress in understanding the bulk behavior of soft materials. However, applications often rely on how these materials behave in complex environments: where confinement, tortuosity, and other physical/chemical factors alter material microstructure, the material itself alters the environment, and these coupled interactions give rise to non-trivial emergent behavior.
Understanding and controlling these interactions is a new frontier for engineering; this is what our lab aims to do.

We tackle this challenge by integrating microscopy and image analysis, microfluidics and rheology, and materials processing and characterization. We also complement our experiments with theoretical modeling, using ideas from fluid dynamics, polymer physics, soft mechanics, equilibrium and non-equilibrium statistical mechanics, and network theory. Our work is thus highly collaborative and multi-disciplinary, combining expertise from engineering, physics, chemistry, biology, and materials science.

We strive to do fundamental research that can make a meaningful, positive impact in society; we do this by focusing on materials and environments relevant to emerging problems in energy, environmental science, and biotechnology. Descriptions of some of our ongoing projects are below, and the results are described in our publications. To find out more, please get in touch!

Fluid flow in porous rocks

Many geophysical situations involve multi-phase flow through a porous rock; key examples include contamination of groundwater aquifers, oil migration and recovery, methane venting, and subsurface CO2 storage. It is difficult to accurately model and control these flows; the physics of how fluids navigate the disordered, tortuous channels of a 3D porous rock is poorly understood. Even just visualizing flow in 3D rocks is typically impossible. After all, rocks are opaque!

Our lab has developed expertise to make disordered porous rocks, with controllable pore structures, that are transparent. This capability allows us to visualize multi-phase flow within them in 3D, with high spatial and temporal resolution, over length scales ranging from smaller than a pore to that of the entire medium. We have already used this platform to elucidate the physical origin of fluctuations and instabilities in some immiscible fluid flows. We are currently building on our work to answer questions like:
  • - How do structural heterogeneities impact flow behavior?
  • - How does the complex rheology of a polymer solution impact how it navigates the pore space?
  • - How do colloidal dispersions reshape the pore space and alter subsequent flow through it?

Structure, mechanics, and transport in deformable porous materials

Many gels, clays, soils, biological structures, foods, pharmaceutical products, and coatings are deformable porous materials that change their structure in response to osmotic and mechanical stresses. We seek to develop better ways to model and control this behavior for applications in agriculture, formulations, and drug delivery.

Our lab has developed tools to study diverse deformable porous materials including packings of soft particles, bulk gels, polymeric microcapsules, and even biological organs. We are using these tools to study the coupling between structure, mechanics, and transport in these systems and answer questions like:
  • - How is flow through a porous medium linked to deformations of its solid matrix?
  • - How can osmotic stresses be used to control deformations in gels?
  • - How does confinement impact these processes?

Soft matter physics in the body

We are beginning to find that many aspects of the structure and functioning of structures in the body--gels, tissues, and even organs--can be described using ideas from soft matter physics. For example, we have shown how dietary fibers can change the structure of mucus in the gut, regulating its protective barrier properties. Remarkably, these interactions can be understood in the framework of polymer physics--thus revealing new physics in the body, and elucidating new principles to understand and control biological processes.

Our lab has developed new experimental and computational tools to probe how polymer properties, fluid dynamics, and soft mechanics can regulate biological structures in the body. We are using these tools to address questions like:
  • - How do the physico-chemical properties of mucus alter transport through it?
  • - How do biomechanical factors regulate the dynamics of respiration?

Emergent behaviors of bacterial communities

Bacterial communities can be beneficial; for example, they can be leveraged in environmental applications to remove pollutants or treat wastewater. They can also be harmful; for example, overgrowth of "bad" bacteria in the gut or the airways is linked to conditions like colitis or cystic fibrosis, respectively. Recent work has resulted in increasingly sophisticated ways to characterize the composition and structure of these communities. However, strategies to control their functions remain lacking.

Our lab has developed tools to study how physical and chemical effects shape bacterial communities and their functions. We have also developed tools to create communities with well-defined architectures and compositions. We are using these tools to understand and control how collective behaviors, like macroscopic motion, robustness to stresses, and the ability to perform chemical reactions, emerge in bacterial communities. Specifically, we seek to answer questions like:
  • - How do environmental stresses impact the spatio-temporal organization of bacterial communities?
  • - How does confinement in porous media alter bacterial behavior?
  • - How can we use 3D printing to create functional communities?

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