(2be) Supporting the Circular Economy and Advanced Manufacturing through Soft-Matter Simulations and Theory

Advanced manufacturing and the circular economy have emerged in the last decade as powerful tools for reducing waste and combatting the climate crisis. These technologies rely on the design and processing of soft-matter materials such as nanogel suspensions, slurries, biomaterials, and polymer melts. My goal is to lead a research group to develop predictive models for the design and processing of soft matter materials. My group will initially focus on three research topics related to this overarching goal.

1. Development of soft-matter constitutive equations through coarse graining

Emerging manufacturing techniques subject fluids to complex flow environments, leading to heterogeneous behaviors such as shear-induced aggregation in slurries and micro phase separation in polymer melt that not captured by existing constitutive equations derived from experimental shear rheology. My group will develop coarse-grained continuum constitutive equations for materials in complex flows from more detailed models using a thermodynamically consistent coarse graining method consisting of alternating Monte Carlo and dynamic steps. The Monte Carlo steps will calculate the stress tensor of the coarse-grained system, and the dynamics steps will determine how the coarse-grained stress relaxes. We will initially employ this algorithm to discrete element models to develop constitutive equations for application towards ceramics printing and to slip-spring models to obtain constitutive equations for polymer melts. This method is highly general and will also be used to develop constitutive equations for biological fluids such as blood and algae solutions.

2. Plastic recycling in the circular economy

Development of a truly circular economy for plastics requires conversion of finished products into raw materials. Polyolefins comprise the largest share of plastic waste but are difficult to recycle because they typically enter the waster stream as immiscible blends. As they are melted and cooled, these blends microseparate into immiscible domains with poor surface adhesion degrading the performance of the recycled plastic. The poor adhesion can be partially mitigated by the presence of compatibilizers at the interface between domains. My group will use continuum theory and simulations to develop predictive models for the mechanical performance of recycled polyolefin blends by answering three key questions. First, how does the morphology of crystalizing melts depend on blend composition? Second, how effective are compatibilizers at migrating towards the interface as the melt crystalizes? Finally, how do micromorphology and compatibilizers influence the mechanical properties of recycled blends? These results will be used to develop processing strategies for optimizing the performance of recycled plastics.

3. Bioprinting

The 3D printing of biomimetic tissue structures is now in reach due to advances in embedded ink-writing of biomaterials containing living cells. The viability and proliferation of cells in the printed structures can be reduced due to damaged sustained during printing. The amount of cellular damage depends on the magnitude, duration, and type of stresses the cell experience as they flow through the printer. My group will develop a theoretical framework for determining the stresses deformable particle (cells, capsules, droplets, microgels) experience in the complex (non-linear, heterogeneous) flow fields found in 3D printers. The framework will be used to develop two key advances in the field of deformable bodies: a Fokker-Plank equation for deformable particles in complex flows and particle level simulation methods that account for deformability. These results will be used to develop predictive models of cell damage in embedded ink-writing and will have application to a variety of industrial and pharmaceutical processes that utilize deformable particles such as water filtration, oil recovery, and drug delivery.

Teaching Interests:

My educational and research background has given me the knowledge and experience necessary to teach all undergraduate chemical engineering courses, as well as graduate level fluid mechanics and mathematics courses. I am interested in teaching and developing classes in rheology and applied mathematics. I have been a teaching assistant for the introductory graduate fluid mechanics course at Cornell University and a microhydrodynamics elective course at Stanford University. In teaching undergraduate courses, I believe that it is important to maintain a balance between teaching fundamental physical mechanism and engineering practice. I will emphasize communication skills and teamwork through presentations and group work when appropriate for the course in order to prepare students for the collaborative nature of modern engineering. At the graduate level, I believe it is important to connect the core mathematical concepts taught in introductory courses to active areas of research in order to give an anchor for some of the abstract concepts introduced at the graduate level.

Ph.D. Dissertation: Micromechanical modeling of heterogeneous dispersions

Ph.D. Advisor: Prof. Roseanna N. Zia

Postdoc Project: Continuum simulation of polymer deposition in Fused-Filament Fabrication

Postdoc Advisor: Prof. Peter D. Olmsted

NRC Postdoc: Coarse-grained, temperature dependent constitutive equations for entangled polymer melts

Mentor: Dr. Jonathan E. Seppala