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Title: Control of the hierarchical assembly of π-conjugated optoelectronic peptides by pH and flow

Self-assembled nanoaggregates of p-conjugated peptides possess optoelectronic properties due to electron delocalization over the conjugated peptide groups that make them attractive candidates for the fabrication of bioelectronic materials. We present a computational and theoretical study to resolve the microscopic effects of pH and flow on the non-equilibrium morphology and kinetics of early-stage assembly of an experimentally-realizable optoelectronic peptide that displays pH triggerable assembly. Employing coarse-grained molecular dynamics simulations, we probe the effects of pH on growth kinetics and aggregate morphology to show that control of the peptide protonation state by pH can be used to modulate the assembly rates, degree of molecular alignment, and resulting morphologies within the self-assembling nanoaggregates. We also quantify the time and length scales at which convective flows employed in directed assembly compete with microscopic diffusion to show that flow influences cluster alignment and assembly rate during early-stage assembly only at extremely high shear rates. This suggests that observed improvements in optoelectronic properties at experimentally-accessible shear rates are due to the alignment of large aggregates of hundreds of monomers on time scales in excess of hundreds of nanoseconds. Lastly, our work provides new fundamental understanding of the effects of pH and flow to control the morphologymore » and kinetics of early-stage assembly of p-conjugated peptides and lays the groundwork for the rational manipulation of environmental conditions to direct assembly and the attendant emergent optoelectronic properties.« less
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Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Organic and Biomolecular Chemistry
Additional Journal Information:
Journal Volume: 2017; Journal ID: ISSN 1477-0520
Royal Society of Chemistry
Research Org:
Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Contributing Orgs:
This research used resources of the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02- 05CH11231. R.A.M. acknowledges a graduate fellowship from the Computational Science and Engineering Program at the University of Illinois.
Country of Publication:
United States
36 MATERIALS SCIENCE; self-assembly; pi-conjugated oligopeptides; molecular simulation
OSTI Identifier: