Title: Atomic-level engineering and imaging of polypeptoid crystal lattices

Abstract

The rational design of supramolecular nanomaterials fundamentally depends upon an atomic-level understanding of their structure and how it responds to chemical modifications. Here we studied a series of crystalline diblock copolypeptoids by a combination of sequence-controlled synthesis, cryogenic transmission electron microscopy, and molecular dynamics simulation. This family of amphiphilic polypeptoids formed free-floating 2-dimensional monolayer nanosheets, in which individual polymer chains and their relative orientations could be directly observed. Furthermore, bromine atom side-chain substituents in nanosheets were directly visualized by cryogenic transmission electron microscopy, revealing atomic details in position space inaccessible by conventional scattering techniques. While the polypeptoid backbone conformation was conserved across the set of molecules, the nanosheets exhibited different lattice packing geometries dependent on the aromatic side chainparasubstitutions. Peptoids are inherently achiral, yet we showed that sequences containing an asymmetric aromatic substitution pattern pack with alternating rows adopting opposite backbone chiralities. These atomic-level insights into peptoid nanosheet crystal structure provide guidance for the future design of bioinspired nanomaterials with more precisely controlled structures and properties.

Authors:

Xuan, Sunting  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-6499-9122"
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Jiang, Xi  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-9589-7513"
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Spencer, Ryan K.  ^[3];

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• Search DOE PAGES for ORCID "0000-0002-1043-3913"
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Li, Nan K. ^[1]; Prendergast, David ^[1]; Balsara, Nitash P.  ^[4];

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• Search DOE PAGES for ORCID "0000-0002-0106-5565"
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Zuckermann, Ronald N.  ^[1]

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• Search DOE PAGES for ORCID "0000-0002-3055-8860"
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+ Show Author Affiliations

1. Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720,, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720,
2. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720,
3. Department of Chemistry, University of California, Irvine, CA 92697,, Department of Chemical Engineering &, Materials Science, University of California, Irvine, CA 92697,
4. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720,, College of Chemistry, University of California, Berkeley, CA 94720

Publication Date:

2019-10-21

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1571319

Alternate Identifier(s):

OSTI ID: 1594936

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Published Article

Journal Name:

Proceedings of the National Academy of Sciences of the United States of America

Additional Journal Information:

Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Volume: 116 Journal Issue: 45; Journal ID: ISSN 0027-8424

Publisher:

Proceedings of the National Academy of Sciences

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; peptoid polymers; cryo-TEM; supramolecular assembly; polymer amphiphiles; nanosheets