Chemical and Biomolecular Engineering at Illinois

Soft Materials and Complex Fluids

Faculty: Ying Diao, Jonathan Higdon, Simon Rogers, Charles Schroeder, Diwakar Shukla, Charles Sing

The Rheology and Microstructure of Soft Matter

Soft materials such as foods, biofluids, personal care products, polymers, oils, paints and coatings and cements undergo intervals of fast flow or strong deformation during their formation, processing, handling, or transport. Performing these tasks quickly, efficiently, and with minimal material loss or process down-time requires an understanding of a material’s rheology. Rheology is study of how materials flow and deform. At Illinois, we use state-of-the-art rheometers to study the viscoelasticity of soft materials.

Viscoelasticity is when a material behaves like a solid and a liquid on different timescales. Silly Putty ™ is a common example of a viscoelastic material that a lot of people are familiar with. It bounces like a solid ball at short times and flows like a thick liquid and long times. To fully understand what happens within a material when it’s undergoing deformation or being flowed, we use scattering methods. Light, X-ray, and neutrons are all used to observe the microstructure of soft matter. The coupling of the bulk rheological and microscopic scattering measurements provides a more complete picture of a material’s behavior and provides an opportunity to engineer the next generation of smart materials.

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Combination of experimental and theoretical approaches for studying rheological properties and tracking microstructure evolution.

Polymer Physics

Polymer physics is a highly active area of research at the University of Illinois Department of Chemical and Biomolecular Engineering Illinois ChBE, focusing on the dynamical and equilibrium properties of long chain macromolecules. ChBE faculty are at the forefront of experimental, computational, and theoretical efforts to provide new ways of understanding and manipulating these materials. Examples of research projects include single chain manipulation of synthetic and biological polymers, understanding non-equilibrium chain dynamics, and controlling nanometer-level solution and melt assembly using block copolymers (in and out of equilibrium). Our work also includes the study of “hybrid” systems, such as understanding the structure and melt rheology of nanocomposites, controlling the structure and dynamics of charged polymers, applying statistical mechanical theory to polymers, and understanding polymer problems in biophysical contexts. These investigations span the continuum between fundamental theory, experimental, and applied research, often in a single project. Many of these projects are collaborative and leverage strong ties in the Departments of Mechanical Science and Engineering and Materials Science and Engineering.

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Research efforts at Illinois are focused on both experimental and theoretical studies of the conformational structure and dynamics of single polymer chains. Small molecules and their interactions with polymers are relevant to the study of DNA-protein interactions and can be studied via computational, coarse-grained models.

 

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Block copolymers, including systems that incorporate charge, can self assemble into nano-structured materials. Polymer physics can be used to inform the design of these systems for materials relevant in energy applications.

Single Polymer Dynamics

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Single DNA molecules are stretched in fluid flow generated in microfluidic devices and visualized using fluorescence microscopy.

At Illinois, we use cutting-edge methods and single molecule techniques to directly observe the dynamics of polymer chains in fluid flow and under non-equilibrium conditions. This approach provides a “window” into studying the molecular behavior of single polymer chains. Long chain macromolecules play an indispensable role in modern society. The intrinsic chemical and physical properties of polymers, in conjunction with processing conditions, give rise to polymeric materials with desired functionality.

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Single chains respond to their environment due to small-molecules, charges, or applied fields. Research at Illinois is focused on understanding single-chain and bulk material response of these systems to stimuli for the development of novel sensory materials.

How does molecular scale behavior give rise to emergent, bulk-level material properties? We use single polymer studies to uncover fundamentally new information regarding the static and dynamic morphology of polymers.

Research in this area brings to bear the power of single molecule techniques to study polymers with complex architectures and heterogeneous chemistries, thereby pushing the current state-of-the-art of the field in new directions.

Self and directed assembly

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Self-assembly processes induce symmetry and order from highly disorganized systems.

Self-assembly is the ‘miraculous’ process by which order emerges out of disorder, a process by which Mother Nature makes highly exquisite forms of matter, including life itself. For production of chemical products, self-assembly processes have a profound impact on the solid-state properties of materials. For instances, difference in crystal packing influences bioavailability and stability of pharmaceutical compounds; morphology of organic semiconductors are critical in determining their charge transport characteristics; controlling the nanoscopic phase separation is key to achieving high-efficiency organic solar cells. Using external forces such as fluid flow, intermolecular interactions and surface structures, we seek to direct the molecular assembly processes to follow the kinetic pathways that yield the desired material properties.

Advanced functional materials

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Printed flexible, transparent sensor chip based on semiconducting polymers for personalized health and environmental monitoring.

Advanced and functional materials hold the key to addressing the grand challenges of our time: sustainable energy, a clean environment and better medicines. These materials range from fuel cells, photovoltaics, electronics, and catalysts to a broad spectrum of biomaterials and nanomaterials. The discovery and development of novel functional materials not only bring about new applications and improved performances, but also enable innovative approaches of material manufacturing in an energy-efficient, environmental-friendly and cost-effective fashion. Research at Illinois is focused at the forefront of materials design and processing to bring a sustainable future closer to reality.