(3bu) Development of Tools to Characterize Complex Soft Matter Systems at the Nanometer Length-Scale

Polymeric materials are used in a wide variety of commercial applications, from nanocomposites in the aerospace industry to biopolymers in the pharmaceutical industry, due to their highly tunable properties. Typically, design of the polymer at the molecular level dictates its macroscopic properties. However, as increasingly complex soft matter systems are developed, such as ion-containing polymer systems for electrolytic applications in batteries and fuel cells, the relationship between polymer structure and properties at different length-scales is unknown a priori, making it difficult to use an efficient materials design loop when developing new materials. Often, this disconnect is due to the intrinsic link between macroscopic performance and properties at the nanometer-length scale that are difficult to measure experimentally and predict from chemical structure. For example, in polymer electrolytes bulk ionic conductivity can be predicted from a polymer’s monomeric friction coefficient, which can only be measured via neutron scattering [1]. My research group will develop experimental and computational tools to measure properties at the molecular length-scale in order to develop models for structure-property relationships in complex soft matter systems such as hybrid polymer-based electrolytes and supramolecular biomaterials. We will use directed self-assembly as a platform to fabricate model systems with tunable and precise nanostructures for nanoscale characterization. Through the development and implementation of advanced scattering techniques, including resonant X-ray, neutron and in-situ scattering, we will directly probe the physics of these materials at the molecular-level. Finally, we will use the insights gained from experiments in conjunction with molecular dynamics simulations to develop new force fields that accurately capture the physics of these complex soft matter systems, through inclusion of parameters such as polarizability. Through a combined computational and experimental approach, my research group will develop tools to characterize complex soft matter systems at the nanometer length-scale in order to develop structure-property relationships to inform new materials design for energy and biological applications.

Research Experience:

Ph.D. Dissertation: Thermodynamics and Dynamics of Block Copolymer Electrolytes

Advisor: Nitash P. Balsara, Department of Chemical Engineering, University California Berkeley

Solid polymer electrolytes can help enable beyond Li-ion battery technologies with improved energy density and safety. My dissertation research focused on experimentally determining the effect of salt concentration on the molecular-level physics of block copolymer electrolytes through the synthesis and characterization of a model system. I began my PhD by synthesizing a library of diblock copolymers and used small angle X-ray scattering experiments to construct a phase diagram of morphology as a function of copolymer properties, temperature, and salt concentration [2, 3, 4]. Based on my vast experimental dataset, I developed a theoretical framework to quantify the effect of salt concentration on the thermodynamics of block copolymer electrolytes [5]. In addition, through neutron scattering and spectroscopy, I measured the effect of salt concentration on polymer dynamics on the monomer- and single-chain-length-scales [1]. This was the first study to cover the time window of 0.1-100 ns in polymer electrolytes. Throughout my PhD, I strove to apply and develop fundamental polymer physics to provide new insights to design electrolyte materials for next-generation batteries.

Postdoctoral Research (starting September 2020): Directed Self-Assembly of Tunable Copolymers for Semiconductor Manufacturing

Advisor: Paul Nealey, Pritzker School of Molecular Engineering, University of Chicago

Selected Publications: (7 of 24)

(1) Loo, W. S., Faraone, A. A., Grundy, L. S., Gao, K. W., Balsara, N. P.; Polymer Dynamics in Block Copolymer Electrolytes Detected by Neutron Spin Echo. ACS Macro Lett., 2020, 9, 639-645.

(2) Loo, W. S., Jiang, X., Maslyn, J. A., Oh, H. J., Zhu, C., Downing, K. H., Balsara, N. P. Reentrant phase behavior and coexistence in asymmetric block copolymer electrolytes. Soft Matter, 2018, 14, 2789 – 2795.

(3) Loo, W. S., Galluzzo, M. D., Li, X., Maslyn, J. A., Oh, H. J., Mongcopa, K. I., Zhu, C., Wang, A. A., Wang, X., Garetz, B. A., Balsara, N. P.; Phase Behavior of Mixtures of Block Copolymers and a Lithium Salt, J. Phy. Chem. B, 2018, 122 (33), 8065-8074.

(4) Loo, W. S., Balsara, N. P.; Organizing Thermodynamic Data obtained from Salt-Containing Polymer Blends and Block Copolymers, J Poly. Sci. B, 2019, 57, 1177-1187.

(5) Loo, W. S., Sethi, G. K., Teran, A. A., Galluzzo, M. D., Maslyn, J. A., Oh, H. J., Moncopa, K. I., Balsara, N. P.; Composition Dependence of Flory Huggins Interactions Parameters of Block Copolymer Electrolytes and the Isotaksis Point, Macromolecules, 2019, 52 (15), 5590-5601.

(6) Loo, W. S., Mongcopa, K.I., Gribble, D.A., Faraone, A.A., Balsara, N.P.; Investigating the Effect of Added Salt on the Chain Dimensions of Poly(ethylene oxide) through Small Angle Neutron Scattering, Macromolecules, 2019, 52 (22), 8724-8732.

(7) Li, X.*, Loo, W. S.*, Jiang, X., Wang, X., Galluzzo, M., Mongcopa, K. I., Wang, A., Balsara, N. P., Garetz, B.; Confined versus Unconfined Crystallization in Block Copolymer/Salt Mixtures Studied by Depolarized Light Scattering, Macromolecules, 2019, 52 3, 982-991. (^* Equal Contributions)

Successful Proposals:

NIST Center for Neutron Research, NGB/NG-7 SANS, NSE, 2019.

Advanced Light Source, Beamline 11.0.1.2 RSoXS, 2018 and Beamline 7.3.3SAXS/WAXS, 2018.

Stanford Synchrotron Radiation Lightsouce, Beamline 1-5 SAXS/WAXS, 2017.

Awards:

2019, Finalist, Excellence in Graduate Polymer Research (AIChE)

2019, Recipient, Women in Chemical Engineering (WIC) Travel Award (AIChE)

2019, Participant, MIT Rising Stars in Chemical Engineering

2019, Finalist, Padden Award (APS DPOLY)

2018, Excellence in Lab Safety Award: Large Chemical Sciences (UC Berkeley)

2016 – 2020, National Science Foundation Graduate Research Fellowship

2015, MIT Eloranta Research Fellowship

2015, MIT Department of Chemical Engineering Outstanding Teaching Assistant Award

2014, 2015, MIT Department of Chemical Engineering Special Service Award

Teaching Experience:

Throughout my career, I have found teaching and sharing my passion for chemical engineering and polymer science to be extremely rewarding. Therefore, I have sought out a variety of teaching and mentorship opportunities. While I was an undergraduate at MIT, I served as a Teaching Assistant for the Chemical Engineering Project Laboratory (10.67) course, in which I mentored two student teams on semester-long research projects. Throughout the course, I supervised laboratory experiments and helped my students develop their technical communication skills through written reports and oral presentations. For my service, I was awarded the Outstanding Teaching Assistant Award for an undergraduate course in the Department of Chemical Engineering. Throughout graduate school, I served as a Graduate Student Instructor (GSI) for three core Chemical Engineering undergraduate courses: Mass Transport and Separations, Thermodynamics, and Introduction to Chemical Engineering. As a GSI, I led weekly lectures through discussion sections, held office hours, organized review sessions, and wrote problem sets and exams. I used mid-term questionnaires to gather direct input on my teaching style from my students and adjusted my approach accordingly to ensure the best possible learning environment. Outside of formal teaching, I served as a mentor to local URM high school students through Students for Environmental Energy Development (SEED). Through SEED, I taught bi-weekly lessons about different forms of alternative energy and mentored a group of students through a semester-long science fair project that focused on their choice of alternative energy. In my lab at UC Berkeley, I have mentored two undergraduate and three graduate students through their first projects.

Teaching Interests:

As a formally trained chemical engineer, I am qualified and eager to teach core courses including thermodynamics, kinetics and reaction engineering, and transport phenomena at the undergraduate and graduate levels. In addition, I am excited to develop elective courses that directly reflect my research interests such as polymer science at the undergraduate level and polymer physics/statistical mechanics, spectroscopy, and advanced characterization techniques of soft materials at the graduate level. I recognize that diverse teaching methods are needed in order to be successful in a classroom of diverse students, and I plan to implement a variety of learning strategies into my courses including interactive hands-on activities and labs, research papers, and innovative design projects. I am passionate about bringing emerging applications of chemical engineering such as flow batteries, drug delivery, and therapeutic agent processing/manufacturing into the classroom to help engage students. As an educator, it is my responsibility to promote anti-racism within science in order to best support the scientific and professional development of BIPOC students and early career researchers. I am committed to creating an inclusive and supportive research group, recruiting and mentoring BIPOC students and making science more accessible through outreach.