Research ArticleCHEMICAL PHYSICS

Sequencing conjugated polymers by eye

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Science Advances  15 Jun 2018:
Vol. 4, no. 6, eaas9543
DOI: 10.1126/sciadv.aas9543
  • Fig. 1 Vacuum deposition and STM imaging of C14DPPF-F polymers.

    (A) Molecular structure of C14DPPF-F. (B) Schematic representation of the experimental setup. HV, high voltage. (C) STM image showing C14DPPF-F adsorbed on Au(111) after annealing to 100°C. The polymer backbones appear as bright rows, and the alkyl side chains are seen as darker rows perpendicular to the backbones. Vbias = −1.8 V, I = 300 pA.

  • Fig. 2 High-resolution STM images of C14DPPF-F polymers on Au(111).

    (A) Submolecular resolution of the polymer backbone and the interdigitation of the alkyl side chains. White arrows indicate gaps in the alkyl chain interdigitation. (B) Molecular model of the polymer backbone overlaid on a section of C14DPPF-F (C atoms are shown in gray, O in red, N in blue, and H in white). The alkyl chains have been substituted with CH3 groups for better visualization. An ABBA defect is visible in the center of the image. Vbias = −1.8 V, I = 300 pA.

  • Fig. 3 Analysis of the mass distribution and defect frequency of C14DPPF-F.

    (A) Histogram of molecular weight distribution determined from STM images (see text for detailed methodology). (B) Frequency of ABBA defects as a function of the polymer chain length expressed as number of (AB) monomers or molecular weight. A linear dependence is visible.

  • Fig. 4 Molecular structure and intermolecular interactions of pristine and defective C14DPPF-F polymers.

    (A and B) Structure of defect-free C14DPPF-F in the all-trans configuration (A) and with a single furan-furan cis arrangement (B), demonstrating specular and parallel DPP orientations, respectively. (C and D) Schematic representation of interstrand interactions for the polymer configurations corresponding to (A) and (B), respectively. The alkyl chains are represented by thin gray lines, and the DPP units are represented by green segments. (E and F) Structure of C14DPPF-F around an ABBA defect in the all-trans configuration (E) and with a single furan-furan cis arrangement (F). The DPP units across the defect are arranged in a parallel and specular orientation, respectively. (G and H) Schematic representation of interstrand interactions for the polymer configurations corresponding to (E) and (F), respectively. The ABBA defects are represented by red dots, and larger gaps in the chain interdigitation are represented by gray-shaded areas.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/6/eaas9543/DC1

    section S1. Synthesis of the C14DPPF-F polymer

    section S2. XRD data of C14DPPF-F thin films

    section S3. Conformation energy difference in model system via ab initio calculations

    section S4. Assignment of A and B units in submonomeric resolved STM images of C14DPPF-F

    section S5. SEC analysis of C14DPPF-F

    section S6. Surface-adsorbed C14DPPF-F polymer strands

    section S7. Preliminary ESD-STM data on PDPPTPT

    fig. S1. XRD of a drop cast thin film of C14DPPF-F.

    fig. S2. Ab initio calculations of the conformation of alkyl chains with respect to the polymer backbone.

    fig. S3. Gas-phase optimized structure of a C14DPPF-F oligomer.

    fig. S4. High-resolution STM images of C14DPPF-F and corresponding molecular models.

    fig. S5. GPC molecular weight analysis of C14DPPF-F at 80°C.

    fig. S6. GPC molecular weight analysis of C14DPPF-F at 160°C.

    fig. S7. STM images of C14DPPF-F polymers deposited on Au(111) and Ag(111).

    fig. S8. STM images of C14DPPF-F polymers deposited on Ag(111) after annealing to 100°C.

    fig. S9. STM images of PDPPTPT polymers deposited on Au(111) after annealing to 100°C.

    References (3236)

  • Supplementary Materials

    This PDF file includes:

    • section S1. Synthesis of the C14DPPF-F polymer
    • section S2. XRD data of C14DPPF-F thin films
    • section S3. Conformation energy difference in model system via ab initio calculations
    • section S4. Assignment of A and B units in submonomeric resolved STM images of C14DPPF-F
    • section S5. SEC analysis of C14DPPF-F
    • section S6. Surface-adsorbed C14DPPF-F polymer strands
    • section S7. Preliminary ESD-STM data on PDPPTPT
    • fig. S1. XRD of a drop cast thin film of C14DPPF-F.
    • fig. S2. Ab initio calculations of the conformation of alkyl chains with respect to the polymer backbone.
    • fig. S3. Gas-phase optimized structure of a C14DPPF-F oligomer.
    • fig. S4. High-resolution STM images of C14DPPF-F and corresponding molecular models.
    • fig. S5. GPC molecular weight analysis of C14DPPF-F at 80°C.
    • fig. S6. GPC molecular weight analysis of C14DPPF-F at 160°C.
    • fig. S7. STM images of C14DPPF-F polymers deposited on Au(111) and Ag(111).
    • fig. S8. STM images of C14DPPF-F polymers deposited on Ag(111) after annealing to 100°C.
    • fig. S9. STM images of PDPPTPT polymers deposited on Au(111) after annealing to 100°C.
    • References (32–36)

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