The Polymer Physics and Complex Fluids Group actively develops novel methods for investigating the equilibrium and non-equilibrium properties of complex particles and complex fluids. We develop and employ cutting-edge theoretical and computational tools to understand the complex interplays within complex fluids, including polymer and biopolymer solutions, extra- and intra-celluar dynamics, and highly confined polyelectrolyte systems.
Currently, advanced simulation models are able to capture the thermodynamics and dynamics of molecules on the nanoscale, while continuum models have been successful in describing material mechanics on the bulk scale. However, a bridge linking the nanoscale to the bulk properties is direly needed. Our group aims to develop multi-spatial/temporal scale methods that seek to link nanoscale properties to microscale mechanics, and microscale mechanics to macroscale phenomena.
Polymer materials are everywhere, they are found in the materials that construct the keyboard we type on to the biological building blocks of our body (DNA, cell membranes). Their properties depend on their chemical composition, topology, size, density and the surrounding matrix. Our group explores the properties of these wonderful molecules in solution.
One challenge for microfluidic and nanofluidic devices for medical diagnostics is whether the reactions that occur inside the devices are highly reproducible. To achieve reproducibliity, one must either have high number of reactions for statistics or control the dynamics and conformation of the molecules. In microflow devices, the number of molecules are few, so the big question is how does one control the dynamics and conformation of biomolecules in microflow ? Our simulations show a physical mechanism with which one may achieve a degree of control.
How do we trap a molecule at a particular location in a micron-scale device ? We explore the possibility of DNA trapping at the flow stagnation point using counter-rotating vortices.
What happens when a semi-flexible string is confined in a space smaller than its shortest flexible segment ? This is what occurs for DNA molecules that are put in nanochannels smaller than 100 nm. Interesting and unexpected behavior of these molecules are found due to the complex interplay between the constricted conformation entropy, electrostatic interactions, hydrodynamic interactions, and bending rigidity.
We are interested in the similarity between the dynamics of blood cells in flow and the dynamics of polymers in flow. It has been known for more than 100 years that blood is a complex, non-Newtonian fluid, with propoerties that depend on the concentration of blood cells. We develop novel methods to study the effects of particle deformation on flow properties.