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Title: Correlating Elastic Properties and Molecular Organization of an Ionic Organic Nanostructure

Mechanical and structural properties of ionically self-assembled nanostructures of meso-tetra(4-sulfonatophenyl)porphyrin (TSPP) and meso-tetra(4-pyridyl)porphyrin (TPyP) are presented. This is the first time that elastic modulus of an ionic porphyrin nanostructure has been reported. X-ray photoelectron spectroscopy (XPS), UV-visible spectra, and elemental analysis all support a stoichiometric 1 : 1 TSPP to TPyP composition. Atomic force microscopy (AFM) revealed that the porphyrin nanostructure is composed of stacked ribbons about 20 nm tall, 70 nm wide, and several microns in length. High resolution transmission electron microscopy (HRTEM) images showed clear lattice fringes 1.5 ± 0.2 nm in width aligned along the length of the nanorod. Selected area electron diffraction (SAED) and powder X-ray diffraction patterns of TSPP:TPyP are consistent with an orthorhombic system and space group Imm2 with lattice parameters a ¼ 26.71 °A, b ¼ 20.16 °A, and c ¼ 8.61 °A. Crystallographic data is consistent with an arrangement of alternating face-to-face TSPP and TPyP molecules forming ordered columns along the length of the nanorods. The structural integrity of the solid is attributed to combined noncovalent interactions that include ionic, hydrogen bonding, and p–p interactions. The values of Young’s modulus obtained for the crystalline TSPP:TPyP nanorods averaged 6.5 ± 1.3 GPa. Thismore » modulus is comparable to those reported for covalently bonded flexible polymeric systems. The robust bonding character of the TSPP:TPyP nanostructures combined with their mechanical properties makes them excellent candidates for flexible optoelectronic devices.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [1]
  1. Washington State Univ., Pullman, WA (United States)
  2. Charles Evans and Associates, Sunnyvale, CA (United States)
  3. Alfred Univ., NY (United States)
  4. Univ. of Wisconsin, Madison, WI (United States)
Publication Date:
OSTI Identifier:
1227056
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nanoscale (Online); Journal Volume: 6; Journal Issue: 1
Publisher:
Royal Society of Chemistry
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 36 MATERIALS SCIENCE Environmental Molecular Sciences Laboratory