Advanced Electron Microscopy of Nanophased Synthetic Polymers and Soft Complexes for Energy and Medicine Applications

Abstract

After decades of developments, electron microscopy has become a powerful and irreplaceable tool in understanding the ionic, electrical, mechanical, chemical, and other functional performances of next-generation polymers and soft complexes. The recent progress in electron microscopy of nanostructured polymers and soft assemblies is important for applications in many different fields, including, but not limited to, mesoporous and nanoporous materials, absorbents, membranes, solid electrolytes, battery electrodes, ion- and electron-transporting materials, organic semiconductors, soft robotics, optoelectronic devices, biomass, soft magnetic materials, and pharmaceutical drug design. For synthetic polymers and soft complexes, there are four main characteristics that differentiate them from their inorganic or biomacromolecular counterparts in electron microscopy studies: (1) lower contrast, (2) abundance of light elements, (3) polydispersity or nanomorphological variations, and (4) large changes induced by electron beams. Since 2011, the Center for Nanophase Materials Sciences (CNMS) at Oak Ridge National Laboratory has been working with numerous facility users on nanostructured polymer composites, block copolymers, polymer brushes, conjugated molecules, organic–inorganic hybrid nanomaterials, organic–inorganic interfaces, organic crystals, and other soft complexes. This review crystalizes some of the essential challenges, successes, failures, and techniques during the process in the past ten years. It also presents some outlooks and future expectations on the basis of these works at the intersection of electron microscopy, soft matter, and artificial intelligence. Machine learning is expected to automate and facilitate image processing and information extraction of polymer and soft hybrid nanostructures in aspects such as dose-controlled imaging and structure analysis.

Machine learning in electron microscopy for advanced nanocharacterization: current developments, available tools and future outlook

“…Therefore, the processing of more complex data, such as the generated by Electron Spectroscopy (ES), still remains a challenge even more arduous than the previously reviewed EM image analysis. 193 This section shines light on whether the advances on spectroscopy can compare to the imaging ones, and in which situations the employed methods can share convenience. In the process, we pinpoint suggestions to push the development of these data types, trying to imitate the ascending trend observed in EM image processing.…”

Cryo-EM for battery materials and interfaces: Workflow, achievements, and perspectives

“…It is cautious to apply ultrasonic treatment for better dispersion because the high-energy wave may destroy the fragile samples, such as Li metal and SEI/cathode electrolyte interphase (CEI). For those large particles and buried solid-solid interface, cryo-FIB or cryo-ultramicrotomy ( Chen, 2021 ) is suggested to thin the sample. If possible, placing a TEM grid in the batteries as a part of the current collector is a smart way to achieve a sample approaching its real electrochemical states, for example, directly plating Li/Na metal on it ( Wang et al., 2018 ).…”

Molecular self-assembled monolayers anomalously enhance thermal conductance across polymer–semiconductor interfaces

“…[5][6][7][8][9] In particular, when polymers are employed in microelectronic devices, their relatively low thermal conductivities bring in a significantly low ITC issue. [10][11][12] Therefore, a careful design of the interface is vital for a hybrid system to achieve good interfacial thermal transport. [13][14][15] Various methods can be used to improve the ITC.…”