(6es) Dynamics of Soft Material Systems Under Electric Fields | AIChE

(6es) Dynamics of Soft Material Systems Under Electric Fields


Sengupta, R. - Presenter, Carnegie Mellon University
Research Group Vision and Impact:

I want to have an impact as a researcher in developing tools for controlling and processing soft material systems using external fields, with a thrust to electric fields. Soft material systems, for example, colloidal dispersions, emulsions and surfactant solutions are important in many chemical engineering processes like formulations design, enhanced oil recovery, and pharmaceutical product development. These systems have properties in between solids and liquids, and their structure can be controlled by forces of the magnitude of thermal fluctuations. The processing of these materials is not simple because flow and processing forces affect their structure and properties.

The response of soft materials scales as the square of the electric fields, unlike other traditional fields which produce a linear response. This means that the same effect can be achieved using a significantly smaller value of the electric field. However, despite tremendous potential, we lack a fundamental understanding of the effect of electric fields on soft materials. This limits the commercial applications of electric field driven technology for processing soft material systems. I want to use my background in electrohydrodynamics and field driven surfactant transport to develop electric fields as a robust tool to manipulate soft materials.

I will work in two different directions under this research theme: (1) uncover fundamental physics of these systems under deterministic electric fields; (2) develop stochastic models to predict system response under fluctuating fields. The first research direction is aimed to thoroughly understand the system under controlled environments. The second direction will provide insight into the system behavior under more realistic processing conditions, where disturbances in operating variables create stochastic fields. I will employ a combination of theoretical, computational and experimental techniques in my research group.

Research Experience:

I have expertise in both computational and experimental methods in the areas of fluid mechanics and interfacial science. During my Master’s dissertation under Prof. Mahesh Tirumkudulu, I developed an experimental platform to measure the speed of crack propagation in thin films of drying colloidal dispersions. In my PhD under Prof. Lynn Walker and Prof. Aditya Khair, I worked on boundary integral computations and asymptotic theory to predict the deformation and breakup of drops under external electric fields. I implemented the computations for constant as well as stochastic external fields. I complemented the computations with experiments on the breakup of oil drops, and drops loaded with colloidal suspensions under electric fields. I also designed an experimental platform to quantify surfactant transport to oil-water interfaces under an electric field. I have a strong background in theoretical, computational and experimental tools, and I plan to combine these approaches in solving future research problems.

Research Interests:

My interest lies in determining the response of soft material systems to external fields (both deterministic and stochastic), in particular electric fields, and use this expertise to control their processing, and inform the design of tailored soft material systems. I hope to extend my work on surfactant transport under electric fields to quantify interfacial rheology as a function of electric fields. This will provide insight into the interfacial properties that are of significance in electrocoalescence of drops, and guide work on electric field assisted emulsification. I also hope to build collaborations with material scientists and chemists to design tailored materials that respond specifically to electric fields.

Another research area I want to delve into in the future is electrokinetic methods for water desalination. This technology uses electric current to remove ionic impurities in water by their adsorption to electrodes or ion-exchange membranes. Despite advances in electrode materials, and cell and membrane design, the lack of coherent models for charge/discharge mechanisms of electrodes, ion adsorption at electrodes and membrane transport equations limits the desalination efficiency of this method. I hope to use my background in electric field driven flows and surfactant adsorption to contribute to this area by elucidating mechanisms of transport and adsorption of ionic impurities in these systems.

PhD Dissertation:

Coupling electric fields and surfactants to quantify the mechanics of fluid-fluid interfaces, under the supervision of Prof. Lynn M. Walker and Prof. Aditya S. Khair, Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA.

Teaching Interests:

My core teaching interests are in the fundamental subjects of fluid mechanics, transport phenomena, mathematical and numerical methods, both at the undergraduate and graduate level. My goal in education will be to develop courses related to soft materials. More specifically, I want to include concepts of electrohydrodynamics in graduate level soft matter or fluid mechanics courses. I even plan to incorporate introductory concepts on soft materials in undergraduate courses to get students excited in this field.

I have had the opportunity to be a teaching assistant for six courses during my academic career. These include undergraduate courses on Heat and Mass Transfer, and Chemical Reaction Engineering, as well as graduate courses on Interfacial Waves, Advanced Mathematical Methods, and Mathematical Modeling of Chemical Engineering Processes. The primary responsibility was to hold frequent office hours, but I have had the opportunity to give lectures and develop questions for exams in some of the courses.