(6gj) Low-Cost, Scalable, and Rapid Platforms in Ultrathin Materials Synthesis for Water and Energy Technologies

With the impending rise in global temperatures over the next century, technologies that address water scarcity or reduce emissions will be critical for mitigating the consequences of global warming. However, many proposed innovations in water and energy technologies require the ability to design novel nanomaterials and nanostructures with unprecedented structural and compositional control, such as ultralow polydispersity pore sizes in membranes to replace energy intensive distillations. With increasingly stringent requirements for precise atomic placement in these materials and the desire to deploy their associated technologies at scale, there is a need for processes that can make materials with sub-nanometer precision that can be performed cheaply and scalably. Further, the future search for nanomaterials will require both novel frameworks to create previously unsynthesizable materials and the development of platforms that can rapidly screen materials properties.

My research interests focus on developing novel low-cost, scalable, and rapid platforms for the engineering of ultrathin materials with atomically-precise nanostructures necessary for water and energy technologies.

I plan to establish an independent and self-sustaining research program that will build upon my past research experience in vapor-phase, layer-by-layer synthetic processes, kinetic modeling, both ex situ and in situ structure and spectroscopic characterization tools, and computer-controlled deposition and testing equipment. Processes that can make ultrathin (<50 nm) films will be essential for creating advanced membrane and catalyst materials where thinner coatings dramatically increase efficiency and performance. Additionally, because vapor-phase chemistries do not require solvents, they can be easily combined with roll-to-roll processing and paired with in situ characterization methods, making them ideal for rapid materials screening. Filling the gap in large, high quality, consistent experimental datasets provides a great opportunity for collaboration with computational researchers who focus on materials.

Because control over confinement and composition in ultrathin coatings have been identified as critical areas for improvement in catalyst and membrane design, my group will initially propose projects related to: (a) controlling pore sizes in ultrathin materials through the vapor-phase synthesis of coordination polymers and MOFs for catalysis and membranes, (b) layer-by-layer ternary materials synthesis through laser-control of temperature for gas separation and electronics applications, and (c) ultrathin organic coatings for breaking scaling relations in electrochemical O₂ and CO₂ catalysis.

Graduate Research

My Ph.D. dissertation with Professor Stacey F. Bent at Stanford University in the Department of Chemical Engineering focused on the development of one novel platform to enable new nanotechnologies, molecular layer deposition (MLD). Derived from atomic layer deposition, this process is a new vapor-phase method for creating coordination networks and polymeric films with sub-nanometer thickness and compositional control that uses surface reactions to grow films layer-by-layer. In addition to working with collaborators to create several new organic chemistries for this platform, I lead the development of an MLD-based electrochemically active manganese alkoxide catalyst film for the production of oxygen. By blending carbon species into manganese oxide, the catalyst showed improved structural stability during electrochemical cycling when compared to traditional manganese oxide. To address a major gap in understanding, I also developed a new paradigm to explain the nucleation and growth behavior of MLD-grown films, dramatically broadening the applicability of this approach. By varying monomer selection, and combining synchrotron-based X-ray characterization methods with kinetic modelling, I was able to draw correlations between the choice of monomers and the resulting film structure and growth rate. The combination of organic and inorganic moieties for the formation of previously unmade materials structures is just beginning to be realized (e.g. metal-organic frameworks), and because these materials can be quickly and easy tested through vapor-phase synthesis techniques, there is great potential to expand work and knowledge in this area.

Postdoctoral Research

I am currently in my second year of postdoctoral research with Professor Jeffrey C. Grossman at the Massachusetts Institute of Technology in the Department of Materials Science. During my time here, I have been building upon my prior work to expand the toolkit for atomic-level control of surfaces while concomitantly applying these advances to membrane architectures. In the United States, ~15% of all energy consumption is used for separations, largely through distillation. In some industries, there is a potential to significantly reduce this energy consumption through the introduction of membrane separation technologies. However, in many cases, membrane fouling prevents their widespread deployment. One promising approach that has already been shown to dramatically reduce fouling is to make membranes electrically conductive. However, current methods for making conductive membranes destroy their underlying structure, or are expensive and non-scalable to produce.

Using the insights gained during my PhD, we have come up with a completely new way to make these membranes conductive while maintaining their structure. By infiltrating traditional polymeric membranes with inorganic precursors, they can be laser annealed into a graphitic form without losing their porosity. By replacing expensive metal or graphene-based conductive coatings with cheaper alternatives, membranes can begin to leverage electric fields for new architectures and improved separation efficiency.

Summary

During the poster session, I will present a more thorough overview of my past and current research, as well as my plan for future research activities, which will continue the development of new platforms for controlling surface properties to enable advanced membrane and catalyst devices. Using my PhD and postdoctoral experience in the assembly of computer-controlled deposition and testing equipment, my future vision is to develop rapid materials screening approaches that leverage the synthetic ease of vapor-phase processes combined with in situ spectroscopic and ellipsometric characterization. By expanding the materials processing toolkit and building fundamental insight into the origins of nanostructures, it is my goal to advance the field of materials development, enabling access to unsynthesizable materials structures which will be critical for future water and energy technologies.

Teaching Interests:

My primary goal in teaching is to enable students to be successful in their future careers by inspiring them to seek understanding and knowledge, by equipping them with the tools to articulate and answer important questions, and by providing them with an inclusive and active teaching style conducive to effective learning. I plan to rely heavily on recent pedagogical advancements in my teaching practice, focusing on active learning approaches, as well as the use of computer, streaming, and video tools to both reduce the redundancy of repeated yearly classes and to broaden access to the teaching materials I produce.

In addition to serving for four quarters as a TA at the University of Washington in computer science, where I taught the introductory Computer Programming I course and the senior level Programming Languages course, I also TAed at Stanford University for the senior level Kinetics and Reactor Design course for two quarters, for which I received a Teaching Assistant Award. I delivered several guest lectures in this kinetics course, served as the departmental Head TA Mentor for two years, and was honored with Stanford’s university-wide Centennial Teaching Assistant Award. I have also worked to improve teaching at Stanford and MIT by helping to run and design material for the Stanford ChemE yearly TA training and by co-organizing an Inclusive Teaching Workshop at MIT.

Because of my educational background, teaching experience, and training in pedagogy, I am confident in my ability to teach any core chemical engineering course at the undergraduate or graduate level. In particular, I am interested in courses that leverage my experience in kinetics, spectroscopy, or synchrotron-based characterization, such as a course in Kinetics and Reactor Design, Surface Chemistry, or Spectroscopy.

Selected Publications:

1. David S. Bergsman, et al. "Manganese Alkoxide Films Grown by Hybrid Atomic/Molecular Layer Deposition for Electrochemical Applications." Under Review
2. Richard G. Closser, Mie Lillethorup, David S. Bergsman, Stacey F. Bent. “Growth of a Surface-Tethered, All-Carbon Backboned Fluoropolymer by Photoactivated Molecular Layer Deposition.” ACS Appl. Mater. Interfaces, 11 (2019) 21988
3. David S. Bergsman^‡, Tzu-Ling Liu^‡, et al. "Formation and Ripening of Self-Assembled Multilayers from the Vapor-Phase Deposition of Dodecanethiol on Copper Oxide," Chem. Mater., 30 (2018) 5694
4. Callisto MacIsaac, ..., David S. Bergsman, Stacey F. Bent. "Atomic and Molecular Layer Deposition of Hybrid Mo-Thiolate Thin Films with Enhanced Catalytic Activity," Advanced Functional Materials, 28 (2018) 1800852
5. David S. Bergsman, Richard Closser, Stacey F. Bent. "Mechanistic Studies of Chain Termination and Monomer Absorption in Molecular Layer Deposition" Chemistry of Materials, 30 (2018) 5087
6. Richard G. Closser, David S. Bergsman, and Stacey F. Bent. "Molecular Layer Deposition of a Highly Stable Silicon Oxycarbide Thin Film Using an Organic Chlorosilane and Water," ACS Applied Materials and Interfaces, 10 (2018) 24266
7. Mie Lillethorup, David S. Bergsman, et al. "Photoactivated Molecular Layer Deposition through Iodo-Ene Coupling Chemistry," Chemistry of Materials, 29 (2017) 9897–9906
8. David S. Bergsman, et al. "Effect of Backbone Chemistry on the Structure of Polyurea Films Deposited by Molecular Layer Deposition," Chemistry of Materials, 29 (2017), 1192
9. Richard G. Closser, David S. Bergsman, Luis Ruelas, Fatemeh S. M. Hashemi, Stacey F. Bent. "Correcting Defects in Area Selective Molecular Layer Deposition," Journal of Vacuum Science& Technology A, 35 (2017) 031509 (Editor's Pick)
10. David Bergsman, Han Zhou, Stacey F. Bent. "Molecular Layer Deposition of Nanoscale Organic Films for Nanoelectronics Applications," ECS Transactions, 64 (2014), 87