Colloidal Systems
In our lab, we are deeply interested in gaining insight into the physics and rheology of particulate systems. Our research primarily focuses on understanding the coupling between intricate structures that different particles form at mesoscale, as a result of their interactions at the microscale, and ultimately the emergent rheological/ mechanics of the colloidal system at the macroscale. We pursue this through detailed simulations and aim to build a truly multi-scale physical description to colloidal rheology, and more generally soft glassy materials.
Thixotropy and rheological hysteresis in colloidal systems
Part of our research focuses on the physics and rheology of colloids, with a particular emphasis on their structure evolution under flowing conditions, and its coupling to the overall rheological response of the system. This is generally referred to thixotropy, referring to time-dependent nature of colloidal rheology. By employing computational techniques like Dissipative Particle Dynamics (DPD), we aim to build systematic structure-flow-property relationship for a wide spectrum of different particulate systems. These include studying the role of particle interactions (adhesion, friction, hydrodynamic, etc.), flow geometry and dynamics, flow type (Poiseulle, simple drag, contracting flows, etc.), particle size dispersity and more.
Dense suspensions
We investigate the rheological complexities of dense suspensions under shear, focusing on their non-Newtonian behavior such as continuous and discontinuous shearthickening. Through detailed simulations of particles with different characteristic (rough and frictional, smooth and frictionless), we uncover the microscopic and mesoscopic origins shear-thickening in these exciting systems. Exploring variations in particle shapes and geometries, we are very much interested in better understanding the relationship between the particle-level tribological characteristics/dynamics, the force/contact clusters that form under different flow regimes, and the bulk rheological features of dense suspensions (we care as much about the normal stresses as we do about shear viscosity).
Emergence of rigidity
We have a keen interest in better understanding colloidal gels, from emergence of rigidity to yielding and rheological hysteresis in attractive colloids. We have built foundational understandings of the formation and coarsening of the colloidal structures both under quiescent and flowing conditions, allowing us to structurally describe concepts such as mutation, aging, and memory formation in colloidal gels. The ultimate goal of our work has always been to enable new structure [and hence mechanical] design of attractive colloidal gels with desirable and maybe even tunable properties.