(7ct) Nuclear Spin Hyperpolarization for Characterization of Materials, Surfaces, and Interfaces

With unmatched chemical specificity and the ability to probe materials across length- and timescales, nuclear magnetic resonance spectroscopy (NMR) and imaging (MRI) are two of the most powerful analytical techniques available to engineers, scientists, and medical professionals. Despite these strengths, sensitivity is limited by the degree of equilibrium nuclear spin polarization, typically at parts per million levels. In order to probe to surfaces, interfaces, and low-concentration solutions, methods for nuclear spin “hyperpolarization” are needed. My laboratory will pursue the development of methodology for targeted, high sensitivity spectroscopy for chemical engineering applications such as structure and chemistry at surfaces and interfaces.

I completed my PhD in Chemical Engineering with Prof. Jeffrey Reimer at UC Berkeley where I investigated optical methods of nuclear spin hyperpolarization in semiconductors, culminating in the discovery of a method to spatially control hyperpolarization and directly image depletion layers at the surface of bulk gallium arsenide¹. This work is an excellent example of how controlling spin hyperpolarization provides both the sensitivity and selectivity to probe surfaces and interfaces.

During my postdoctoral research with Prof. Alexander Pines I have worked on a wide range of topics ranging from fundamental spin dynamics to geochemical exploration with novel magnetic resonance detection in boreholes. My work in combining dynamic nuclear polarization with photophysics in diamonds has resulted in one of the highest levels of room-temperature hyperpolarization ever observed². As a faculty member, I will leverage my fundamental understanding of spin interactions for chemical engineering applications. This project will be generally organized as follows:

1. Understanding the transport and equilibrium properties of interacting spins from microscopic to macroscopic scales.
2. Targeting and localization of hyperpolarization as a selective chemical and structural probe at surfaces and interfaces.
3. Chemical engineering applications to interfaces, surface science, and catalysis.

I also seek to extend NMR beyond the traditional model requiring a high-field superconducting magnet in a dedicated facility. Low-field NMR allows the use of cheap, portable magnets in benchtop and truly portable systems. Zero-field NMR allows the observation of spin-interactions that are invisible in the presence of a magnetic field, providing additional information about material structure, geometry, and dynamics³. Furthermore, zero-field experiments are free from the deleterious effects of inhomogeneous magnetic susceptibility, enabling high-resolution study of heterogeneous materials.

1. King, J. P. et al. “Optically rewritable patterns of nuclear magnetization in gallium arsenide.” Nature Communications 3:918 doi: 10.1038/ncomms1918 (2012).
2. King, J. P. et al. “Room-temperature in situ nuclear spin hyperpolarization from optically pumped nitrogen vacancy centres in diamond.” Nature Communications 6:8965 doi: 10.1038/ncomms9965 (2015).
3. J. W. Blanchard, T. F. Sjolander, J. P. King, M. P. Ledbetter, E. H. Levine, V. S. Bajaj, D. Budker, and A. Pines. “Measurement of untruncated nuclear spin interactions via zero- to ultralow-field nuclear magnetic resonance.” Phys. Rev. B 92, 220202(R) (2015).

Teaching Interests:

My teaching philosophy can be stated concisely: effective teaching is the facilitation of effective learning. While this statement is simple, in practice it presents these challenges: How do we define effective learning? How do we assess if learning has occurred? What steps do we take based on this assessment? I will present my plan to address these challenges in the chemical engineering curriculum. I am interested in teaching all aspects of the core curriculum, but with my background would be especially interested in teaching thermodynamics, fluid dynamics, and transport phenomena at the undergraduate and graduate levels. I would also develop special classes in the theory and application of spectroscopic techniques.