Uncovering Self-Assembly Pathways in Polymer Blends by X-Ray Scattering

ABSTRACT

Understanding the implications of component formulation is crucial to industrial use and scale-up of molecular, polymeric, and composite materials. Each new blended additive, however, expands both the compositional dimensionality and the processing complexity, complicating material optimization but introducing possibilities for synthesizing metastable materials with novel functional properties. For nanoscale structures, the exceptional brilliance of synchrotron X-ray sources renders small-angle X-ray scattering (SAXS) a rapid and information-rich characterization method well-suited to this challenge. This talk will feature research at the Center for Functional Nanomaterials applying synchrotron x-ray scattering to accelerate the discovery and design of nanomaterials using self-assembling polymer blend films. I will discuss the use of high-throughput SAXS on combinatorial samples for fine-grained delineation of nanoscale morphologies across a complete ternary composition space. I will also show how machine-guided autonomous SAXS aids the discovery of emergent morphologies in the lithographically directed self-assembly of block copolymer blends. Finally, I will present a new platform for characterizing soft nanomaterial films that combines spray-processing with in situ SAXS. Using this platform reveals how assembly pathways leading to distinct, metastable nanoscale morphologies can be selected on demand by modestly adjusting casting conditions. Taken together, these advances demonstrate the power of leveraging X-ray scattering to direct the nonequilibrium self-assembly of blended nanomaterials.

BIOGRAPHY

Gregory Doerk is a staff scientist at the Center for Functional Nanomaterials (CFN), a Department of Energy (DOE) scientific user facility operated at Brookhaven National Laboratory. Dr. Doerk earned his PhD in Chemical Engineering from the University of California, Berkeley in 2010. Prior to joining the CFN, he performed postdoctoral research at IBM, investigating polymer-directed self-assembly for integrated circuit patterning, and then worked as a research staff member at HGST, a Western Digital company. Dr. Doerk is a recipient of the 2021 DOE Office of Science Early Career Research Program Award. His current research merges polymer self-assembly, new instrumentation, and high-throughput methods to produce new materials for chemical separations, advanced electronics, and energy harvesting.