Groundbreaking Imaging Technique Unveils First-Ever 2D Chainmail-Inspired Material

An innovative imaging method conceived at Cornell has uncovered the first two-dimensional, mechanically interlinked polymer – affirming a leap forward in both material innovation and electron microscopy.

Mirroring the interwoven links found in chainmail, the nanoscale substance was created by scientists at Northwestern University and possesses extraordinary flexibility and toughness, making it a potential candidate for uses like lightweight body armor and ballistic textiles.

Released on Jan. 16 in the journal Science, the research marks several significant advancements. The material showcases 100 trillion mechanical connections per square centimeter, the highest bond density ever accomplished, based on the researchers’ findings. The polymer’s elevated crystallinity and interlocking architecture were validated at Cornell, where tilt-corrected bright field imaging processed a crystalline material at the atomic level for the first time.

“The outcomes were astounding – sharp and high-contrast – clearly depicting the structure,” stated Schuyler Zixiao Shi, a doctoral candidate who conducted the imaging under the guidance of David Muller, the Samuel B. Eckert Professor in the School of Applied and Engineering Physics and co-director of the Kavli Institute at Cornell.

Shi and Muller were co-authors of the study, which was spearheaded by William Dichtel, a chemistry professor at Northwestern.

In 2021, Cornell’s electron microscopists established a global record by imaging complex metal oxides with atomic precision using a technique known as electron ptychography. Nevertheless, imaging polymers presents an added obstacle – they are extremely responsive to electron beams, and their structures can swiftly deteriorate under high-energy electron exposure.

To tackle this challenge, teams led by Muller and Lena Kourkoutis, the late associate professor of applied and engineering physics, devised an imaging technique referred to as tilted-corrected bright field. This approach allows for the imaging of beam-sensitive substances, such as polymers and biological samples, with a resolution comparable to that of electron ptychography.

The primary developer of this technique, Yu Yue, Ph.D. ’23, laid the groundwork for this advancement. Building upon this foundation, Shi illustrated the method’s extraordinary capability by achieving atomic-resolution imaging of the novel polymer, uncovering its intricate chainmail-like arrangement for the first time.

“Unlike electron ptychography, this method necessitates considerably fewer computing resources while securing comparable resolution when the signal on electron detectors is weak,” Shi noted. “With tilted-corrected bright field, researchers were enabled to visualize the zigzag polymer chains knitting together into a flexible 2D chainmail composition that bends locally while preserving its strength.”

Shi further mentioned that in addition to its independent functions, tilted-corrected bright field can act as a real-time diagnostic instrument for ptychography, offering valuable insights and cutting down on computational time for ptychographic reconstructions.

Schuyler Zixiao Shi and Diane Tessaglia-Hymes, communications expert for Cornell Engineering, contributed to this article.