(4bn) Sustainable Materials: From Energy Storage to Biomaterials and New Opportunities in Chemical Engineering Research

Energy, water, and healthcare are three major challenges humanity is facing today and it is widely accepted that the solutions to these problems need to be more sustainable, will use renewable resources, and at the same time will be affordable. Origin and development of the modern Chemical Engineering in the last century was mostly based on usage of petroleum based sources and sustainable, bio-based alternatives have not received the same attention in development. Social and political pressures are driving industrial interest in alternative materials, but transformative advances in measurements, methods and models are critical to success and Chemical Engineers will play an important role for this transformation. Specifically, for the development of alternative materials, it is important that we select suitable materials system, understand and optimize their properties as a function of structural hierarchy (from molecular to macro scale) using conventional and newly developed measurement techniques, develop and optimize processing strategies. In this spirit, as a new faculty, I would like to investigate the synthesis/processing-structure-property relationships for various sustainable materials, with the goal of applying these materials to different challenging applications, ranging from energy storage to new generation bio-materials.

Specifically, I would like to develop a research program in the following areas:

A.Mechanics of bio-based/bio-inspired soft materials

B.Carbon materials from natural resources with hierarchical pore structures for energy storage and water purification

The research program will be developed based on my expertise in chemical engineering and materials science and the program will emphasize a multidisciplinary approach that encompasses knowledge and skills covering the chemical, physical, and life sciences and engineering. The techniques/platforms will be used in my group are lab-on-a-chip, rheology, polymer processing (electro-spinning, extrusion), high temperature materials processing, etc.

Presently, I am a postdoctoral researcher working in the polymer characterization and measurement group at the National Institute of Standards and Technology (NIST), where I am developing microfluidics/lab-on-a-chip based platform to investigate the enzymatic polymerization of biodegradable polymers.¹ The goal is to provide systematic, rigorous and quantitative characterization for these poorly understood systems. We studied Candida Antartica Lipase B (CAL B) catalyzed ring opening polymerization of ε-caprolactone to polycaprolactone ( a model system) in inexpensive metal microrecactors. Metal microreactors enabled us to perform polymerization reactions in organic media and at high temperatures. By implementing a suitable reactor design we have achieved (1) faster polymerization rate and (2) higher molecular weight of polycaprolactone in microreactors compared to that obtained in batch reactors at similar experimental conditions.

Before joining NIST, I was a post-doctoral research associate at the Polymer Science and Engineering Department of University of Massachusetts-Amherst. I was involved in investigating surface, near surface and mechanical characterization of gel/hydrogel/elastomeric materials.^2-4 The mechanical properties of gels present qualitatively contradictory behavior; they are commonly soft but also notoriously brittle. I investigated the elasticity and fracture behavior of swollen polymer networks using a simple experimental method to induce cavitation within polyacrylamide hydrogel, a common material used in many biological applications. A transition from reversible cavitation to irreversible fracture was observed with the increase of polymer volume fraction. Adapting scaling theories, it is shown quantitatively that the transition from reversible cavitation to irreversible fracture depends on the polymer volume fraction and an initial defect length scale.² Application of this simple technique (cavitation rheology) provides opportunities for studying mechanical properties in both synthetic polymer networks and biological tissues from molecular to macroscopic length scales at an arbitrary location.

In my Ph.D. research I have studied the flow and three dimensional microstructure of a liquid crystalline carbonaceous material (mesophase pitch) for different flow conditions, such as steady shear flow, dynamic flow, and processing flow using polarizing optical microscopy and X-ray diffraction.^5-9 The evolution of microstructure in different flow conditions was uniquely studied in three orthogonal planes. The systematic understanding of flow and its effect on microstructure helped us to predict/model the complex flow behavior and microstructural evolution of this material, which in turn will help to design carbon materials, such as carbon fibers, battery electrodes, carbon-carbon composites, and fuel cell separators in more efficient ways. My dissertation, ?Investigation of flow and microstructure in rheometric and processing flow conditions for liquid crystalline pitch', has been awarded the Best Dissertation in Carbon Science, 2007 for ?outstanding scientific achievement' by the Elsevier-Carbon Journal.

In addition to research, I am passionate about teaching and am inspired to educate and to mentor future scientists and engineers to meet the challenges of today's ever-changing technologies. My teaching philosophy has been developed through my experience as a lab and teaching assistant during my graduate school days, and as a supervisor during my industrial tenure. I can teach traditional undergraduate and graduate level chemical engineering courses. In addition, I intend to offer advanced graduate level courses in polymer adhesion, fabrication and characterization of nanostructured materials, viscoelasticity of polymers and biopolymers: theory and simulation.

References:

1.Kundu S, Bhangale A, William WE, Flynn KM, Gross RA, Beers KL. Immobilized enzyme catalyzed polymerization reactions in microreactors. Polymer Preprints 2010, 51(1), 745.

2.Kundu S, Crosby AJ. Cavitation and fracture behavior of polyacrylamide hydrogels, Soft Matter 5(20), 3963-3968 (2009).

3.Kundu S, Crosby AJ, Sharma R. Adhesion Behavior of Non-planar Wrinkled Surfaces, to be submitted.

4.Breid D, Kundu S, Denic V, Crosby AJ. Curvature effect on the wrinkle morphology, in preparation.

5.Kundu S, Grecov D, Rey AD, Ogale AA. Shear flow induced microstructure of a synthetic mesophase pitch, Journal of Rheology 53(1):85-113(2009).

6.Kundu S, Ogale AA. Rheostructural studies on a synthetic mesophase pitch during transient shear flow, Carbon 44(11): 2224-2235 (2006).

7.Kundu S, Ogale AA. Microstructural effects on the dynamic rheology of a discotic mesophase pitch, Rheologica Acta 46(9):1211-1222 (2007).

8.Kundu S, Naskar AK, Ogale AA, Anderson D, Arnold JR. Observations on a low-angle x-ray diffraction peak for AR-HP mesophase pitch, Carbon 46(8):1166-1169 (2008).

9.Kundu S, Ogale AA. Rheostructural studies of a discotic mesophase pitch at processing flow conditions, Rheologica Acta, In press, 2010.