(630c) Morphological Characterization of 2D Polymers and Materials: TEM Imaging Processing and Computational Analysis

Recent research has shown an increased interest in the development of polymers that can extend covalently in two dimensions. This type of material has the potential to combine the mechanical strength and in-plane energy conduction of conventional two-dimensional (2D) materials with the low densities, synthetic processability, and organic composition of their one-dimensional counterparts. 2D polymers and materials possess unique properties such as ultra-thinness, well-organized pore structures, and high chemical stability, making them highly attractive for a range of applications, including nanotechnology and devices. One promising area of research involves altering the 2D layered structure of these materials to create barriers through staggered platelet stacking or perm-selective separation membranes via aligned pore structures. Nevertheless, comprehensive studies are required to validate the 2D formation and layered stacking structure, which necessitates combining material characterization techniques and computational tools.

In our recent study, we designed and synthesized a 2D polyaramide-1 (2DPA-1) using irreversible polycondensation chemistry [1]. This approach offers mechanical processability and high chemical stability, making it an ideal candidate for further investigation. Our current work focuses on exploring how the 2DPA-1 polymer molecules, which are noncovalently linked by interlayer hydrogen bonds, can be realigned into highly organized nanofilms using various techniques such as solvent retreatment, spinning coating, drop-casting, and scotch tape exfoliation. To analyze the resulting 2D structures, we use a combination of transmission electron microscopy (TEM) imaging and computational processing tools. These tools enable us to assess the ultra-thin sheet-like structure (0.4 nm thickness) and estimate possible 2D platelet orientations and layered structural packing. The image processing tools also allow for high throughput structural analysis of 2D platelets and polymers. Overall, our study provides insights into 2D material morphologies and highlights the importance of combining material characterization techniques and computational tools to fully understand their properties and potential applications.

[1] Zeng, Y., Gordiichuk, P., Ichihara, T., Zhang, G., Sandoz-Rosado, E., Wetzel, E. D., ... & Strano, M. S. (2022). Irreversible synthesis of an ultrastrong two-dimensional polymeric material. Nature, 602(7895), 91-95.