title: Thermodynamic factors impacting the peptide-driven self-assembly of perylene diimide nanofibers.
abstract: Synthetic peptides offer enormous potential to encode the assembly of molecular electronic components, provided that the complex range of interactions is distilled into simple design rules. Here, we report a spectroscopic investigation of aggregation in an extensive series of peptide-perylene diiimide conjugates designed to interrogate the effect of structural variations. By fitting different contributions to temperature dependent optical absorption spectra, we quantify both the thermodynamics and the nature of aggregation for peptides by incrementally varying hydrophobicity, charge density, length, as well as asymmetric substitution with a hexyl chain, and stereocenter inversion. We find that coarse effects like hydrophobicity and hexyl substitution have the greatest impact on aggregation thermodynamics, which are separated into enthalpic and entropic contributions. Moreover, significant peptide packing effects are resolved via stereocenter inversion studies, particularly when examining the nature of aggregates formed and the coupling between π electronic orbitals. Our results develop a quantitative framework for establishing structure-function relationships that will underpin the design of self-assembling peptide electronic materials.
authors.affiliation: MacDiarmid Institute for Advanced Materials and Nanotechnology, ‡School of Chemical and Physical Sciences, Victoria University of Wellington , P.O. Box 600, Wellington 6012, New Zealand.
authors.forename: Galen L
authors.initials: GL
authors.lastname: Eakins
authors.forename: Joseph K
authors.initials: JK
authors.lastname: Gallaher
authors.forename: Robert A
authors.initials: RA
authors.lastname: Keyzers
authors.forename: Alexander
authors.initials: A
authors.lastname: Falber
authors.forename: James E A
authors.initials: JE
authors.lastname: Webb
authors.forename: Alistair
authors.initials: A
authors.lastname: Laos
authors.forename: Yaron
authors.initials: Y
authors.lastname: Tidhar
authors.forename: Haim
authors.initials: H
authors.lastname: Weissman
authors.forename: Boris
authors.initials: B
authors.lastname: Rybtchinski
authors.forename: Pall
authors.initials: P
authors.lastname: Thordarson
authors.forename: Justin M
authors.initials: JM
authors.lastname: Hodgkiss
mesh_terms: D000595:Amino Acid Sequence; D019277:Entropy; D057927:Hydrophobic and Hydrophilic Interactions; D007094:Imides / Q000737:chemistry*; D057139:Nanofibers / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry; D013237:Stereoisomerism; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D007094:Imides; D010455:Peptides; C521332:perylenediimide; D014867:Water; D010569:Perylene