Properties of soft crystalline materials such as synthetic polymers are governed by locations of constituent atoms. Determining atomic-scale structures in these materials is difficult because they degrade rapidly when studied by electron microscopy, and techniques such as x-ray scattering average over volumes much larger than coherent blocks of the unit cells. To our knowledge, there are no direct atomic-scale images of synthetic polymers. I will present results on crystalline sheets formed by self-assembly of an amphiphilic diblock copolypeptoids in water. Low-dose images of the sheets were obtained by cryogenic electron microscopy. Sorting and averaging algorithms, developed by the structural biology community, were used to extract high resolution information from low dose images. Superposition of images results in micrographs that show the locations of atoms in the polypeptoid crystals. In particular, we determine the orientation of phenyl rings and the location of individual bromine atoms that are in the peptoid side-chains. Efforts to apply this approach to other synthetic polymers are currently underway.

Imaging atoms in crystalline polymer films

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.