I joined MIT as a postdoctoral associate in 2006, after finishing my Ph.D. with Prof. T. Sridhar at Monash University, Australia. During my Ph.D. work, I studied the extensional flow behavior of polymer solutions using the filament stretching extensional rheometric technique. At MIT, I work at the Institute for Soldier Nanotechnologies, under the combined supervision of Prof. G. H. McKinley (Mechanical Engineering), and Prof. G. C. Rutledge (Chemical Engineering). The major focus of my research at MIT-ISN is to understand the role that the fluid viscoelasticity plays in manufacturing polymer fibers using the electrospinning process. A brief description of the projects I am invovled in is provided below.

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Electro-spinning of polymer solutions

Electro-spinning is a process of manufacturing fine fibers from polymeric fluids using an electric field. Recent interest in electro-spinning arises from its potential use in the fabrication of  nano-fibers for various applications. In a typical electro-spinning process the polymeric fluid undergoes substantial deformation at very large deformation rates. This invokes a characteristic viscoelastic response from the fluid which critically influences, both the stability of the process, as well as the final characteristics of the product fiber. In the current research project these effects are systematically being studied. Particular emphasis is being directed towards the understanding of how the fluid properties affect the diameter of the product fibers. The  goals of this project are as follows.
 

• To construct a reduced dimensionality model for electro-spinning of nanofibers including the effects of viscoelasticity and surface evaporation.
• To develop a stable experimental system for electro-spinning of polymer melts.
• To develop protocols that would allow electro-spinning of fluids with nano-filler components (like nano-tubes, nano-clay, ferrofluid particles etc).

Extensional rheology of polymer melts and solutions

The dynamics of polymer molecules in extensional flows is interesting since such flows arise in a number of important polymer processing operations like melt spinning, film blowing, injection molding etc. The above mentioned electro-spinning process also uses a predominantly extensional mode of deformation. These processes typically elongate the polymeric fluids by large amounts, leading to substantial orientation, and stretching, of the polymer chains. The resulting stress in the fluid gives rise to spectacular non-Newtonian effects which play a critical role in determining the stability of the process. These non-linear effects in extensional flow can now be studied using the Filament Stretching Extensional Rheometer (FiSER), from a fundamental stand-point. Current topics of interest include characterization of extensional flow behavior in polymer melts.