Single-Molecule Electron Transport in Peptoids

Prempin, Brittany; Samajdar, Rajarshi; Chhabra, Hemani; Meigooni, Moeen; Aksimentiev, Aleksei; Tajkhorshid, Emad; Moore, Jeffrey S.; Schroeder, Charles M.

doi:10.1021/acs.jpcb.5c07788

Single-Molecule Electron Transport in Peptoids

Journal Article · Wed Mar 04 00:00:00 EST 2026 · Journal of Physical Chemistry. B

DOI:https://doi.org/10.1021/acs.jpcb.5c07788· OSTI ID:3023769

Prempin, Brittany ^[1]; Samajdar, Rajarshi ^[1]; ^[1]; Meigooni, Moeen ^[1]; ^[1]; ^[1]; ^[1]; ^[2]

University of Illinois Urbana-Champaign, IL (United States)
University of Illinois Urbana-Champaign, IL (United States); Princeton University, NJ (United States)

Peptoids are structural analogs of peptides in which side chains are appended to the backbone nitrogen rather than the α-carbon. The sequence-defined modularity of peptoids enables precise control over structure−function relationships, enabling applications in energy storage and biomedical materials. Despite recent progress, the role of sequence and conformation on electron transport in peptoid molecules is not fully understood. Here, we synthesize a library of peptoid oligomers and characterize their molecular electronic properties using the scanning tunneling microscope-break junction (STM-BJ) technique. Our results show well-defined electron transport behavior for peptoid sequences containing aromatic side groups lacking hydrogen bonds (H-bonds) and without chemical substitutions at the N−C_α position. This behavior fundamentally differs from electron transport in peptides, where H-bond interactions give rise to higher conductance states. All-atom molecular dynamics (MD) simulations are used to understand the conformational heterogeneity of peptoids, and molecular conformations obtained from MD simulations are used in quantum mechanical calculations based on the nonequilibrium Green’s function−density functional theory (NEGF-DFT) formalism. In all cases, computational results are in reasonable qualitative agreement with experiments. Our work demonstrates that the conductance behavior of peptoids depends on monomer identity, including side-chain aromaticity and substitution at the N−C_α position. Overall, this work provides new insights into the structure−function relationships governing electron transport in peptoid-based materials and establishes design rules for peptoid-based molecular junctions.

View Accepted Manuscript (DOE)

Research Organization:: University of Illinois Urbana-Champaign, IL (United States)

Sponsoring Organization:: Army Research Office (ARO); USDOE Office of Science (SC), Basic Energy Sciences (BES)

Grant/Contract Number:: SC0022035

Other Award/Contract Number:: W911NF-22-2-0246

OSTI ID:: 3023769

Journal Information:: Journal of Physical Chemistry. B, Journal Name: Journal of Physical Chemistry. B Journal Issue: 11 Vol. 130; ISSN 1520-6106; ISSN 1520-5207

Publisher:: American Chemical SocietyCopyright Statement

Country of Publication:: United States

Language:: English

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