Although nanometer-scale kinetic and dynamic processes in liquids are a unifying feature of industrial chemistry, advanced materials and biology, our measurement capabilities to directly visualize and quantify these processes are usually limited to large objects and slow behavior. Recent technological advances in electron microscopy instrumentation, including ambient liquid sample holders and fast cameras that detect electrons directly, have overcome these limitations to provide a previously unobtainable feat - direct, high-frame rate and high-spatial-resolution video electron microscopy of fluids, soft materials and interfaces between different materials. This project involves the acquisition of these combined instrumental capabilities for incorporation with a state-of-the-art electron microscope at the University of California, Santa Barbara. Combined with advanced dynamic image analysis methods, these new capabilities provide a foundational tool for fundamental studies of kinetic and dynamic processes in liquids at the single-molecule and single-particle level and establish core expertise in dynamic liquid nanostructure visualization on the campus. The new capabilities also inspire a new generation of researchers to push the boundaries of liquid electron microscopy and the science it enables.
This Major Research Instrumentation grant allows acquisition of an in-situ liquid cell holder with on-chip temperature, flow and electrochemical control, together with a third-generation direct electron detector. Combined with a newly installed state-of-the-art electron microscope, ThermoFisher/FEI Talos F200X G2, this acquisition allows for direct visualization of liquids with high spatial (0.2 nm) and temporal (above 1 kHz) resolution under a range of ambient conditions and applied electrical fields through on-chip high-field circuitry on the liquid cell. The ability to modify the sample-cell interface in the liquid cell and use flow to rapidly exchange fluids help realize unprecedented experiments to directly observe a wide range of physicochemical processes in unconfined, nano-confined and interfacial fluids including phase transformations, molecular motions and interactions, as well as chemical and electrochemical reactions. The large data sets from these experiments benefit from a suite of newly developed video microscopy analysis tools to resolve and quantify the complex and often subtle features of kinetic and dynamic processes in nanoscale liquids. These powerful new tools are deployed to address some of the most impenetrable and vexing scientific challenges in materials science and structural biology, including (i) metastable and unstable phase separation during nanoconfinement and nanomaterial synthesis, (ii) single-molecule electrochemical characterization of catalytic materials, and (iii) fundamental mechanisms of aggregation and coacervation in disordered biomolecules.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
