Research ArticleMATERIALS SCIENCE

Poly(amide-imide) materials for transparent and flexible displays

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Science Advances  26 Oct 2018:
Vol. 4, no. 10, eaau1956
DOI: 10.1126/sciadv.aau1956
  • Fig. 1 Transparent and thermostable poly(amide-imide)s with low CTE.

    (A) Synthetic route to PAIs. (B) Photo of PAI(s-u) freestanding film. Photo credit: Byungyong Lee. (C) Relationship of transmittance and CTE as a function of u diamine content in the PAI.

  • Fig. 2 Analysis of thermal expansion behavior of poly(amide-imide)s.

    (A) Representative 2D GIWAXS data of the PAI(s-s), PAI(s-u), PAI(u-s), and PAI(u-u). (B) Azimuthal profile in the qz direction, which was deconvoluted assuming Gaussian functions. arb. units, arbitrary units. (C) A plot of π-π stacking distance versus u(u + s). (D) A plot of CTE versus π-π stacking distance.

  • Fig. 3 Optimized structures of poly(amide-imide)s’ repeating units.

    Optimized structures of PAI(s-s) (A), PAI(s-u) (B), PAI(u-s) (C), and PAI(u-u) (D) repeating units by DFT calculations. Their corresponding binding energies are also given. The red dotted lines indicate hydrogen bonds. The π-π stacking structures between two biphenyl units along with the distances between two phenyl rings are separately shown on the right side.

  • Fig. 4 TFT device fabricated on poly(amide-imide) film.

    (A) Schematic structure of the transparent and flexible IGZO TFT fabricated on PAI(s-u). (B and C) Electrical characteristics (B) and transmittance spectra (C) of the IZGO TFTs. (D) TFT performance as a function of bending radius.

  • Table 1 Characterization of PAIs.
    Polymer codeu/(u + s)*ηinh
    (dl g−1)
    λco (nm)T550 (%)§Td5 (°C)CTE (ppm/°C)
    In N2In airSecond runThird run
    PAI(s-s)0.003.76371884574328.79.5
    PAI(s-su)0.253.90371884684746.17.4
    PAI(su-s)0.252.90364884974795.65.2
    PAI(s-u)0.503.98371884784844.24.4
    PAI(u-s)0.503.02371894854864.65.7
    PAI(su-su)0.503.40371884824924.84.8
    PAI(su-u)0.753.62371885114965.66.1
    PAI(u-u)1.003.50371884654767.57.6

    *Molar fraction of uDA-originated repeating units in the total diamine content.

    †Inherent viscosity measured in NMP at 0.5 g dl−1 concentration at 30°C.

    ‡Cutoff wavelength determined by UV-vis spectra of freestanding polymer films 70 to 80 μm thick.

    §Transmittance at 550 nm.

    ║5% weight loss temperature measured by TGA at a heating rate of 10°C/min.

    ¶Calculated from the mean coefficient of linear thermal expansion between 50° and 250°C in the second and third heating runs, respectively.

    Supplementary Materials

    • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/10/eaau1956/DC1

      Fig. S1. Synthetic route to uDA.

      Fig. S2. 1H NMR spectra of the nitro intermediate 2 and uDA.

      Fig. S3. 13C NMR spectra of the nitro intermediate 2 and uDA.

      Fig. S4. FTIR spectra of the nitro intermediate 2 and uDA.

      Fig. S5. Synthetic route to diacids.

      Fig. S6. 1H NMR spectra of the diacids uDAc and sDAc.

      Fig. S7. 13C NMR spectra of the diacids uDAc and sDAc.

      Fig. S8. FTIR spectrum of uDAc.

      Fig. S9. 1H-NMR spectra of PAIs.

      Fig. S10. Photos of PAI films.

      Fig. S11. UV-vis spectra of PAIs.

      Fig. S12. TGA data of PAIs.

      Fig. S13. DSC data of representative PAIs.

      Fig. S14. DMA data of PAIs.

      Fig. S15. TMA data of PAIs.

      Fig. S16. 2D GIWAXS data of PAIs.

      Fig. S17. 1D deconvoluted plot of the GIWAXS data in out-of-plane direction.

      Fig. S18. 1D deconvoluted plot of the GIWAXS data in in-plane direction.

      Fig. S19. A plot of CTE and π-π stacking distance versus β-relaxation temperature determined by the DMA.

      Fig. S20. Synthetic route to model compound amide-uDA and imide-uDA.

      Fig. S21. 1H NMR spectra of model compounds amide-uDA and imide-uDA.

      Fig. S22. 13C NMR spectra of model compound amide-uDA and imide-uDA.

      Fig. S23. FTIR spectra of model compound amide-uDA and imide-uDA.

      Fig. S24. Chemical and crystal structures of model compound amide-uDA and imide-uDA.

      Fig. S25. Ten most stable structures of PAI(s-s).

      Fig. S26. Ten most stable structures of PAI(s-u).

      Fig. S27. Ten most stable structures of PAI(u-s).

      Fig. S28. Ten most stable structures of PAI(u-u).

      Fig. S29. Transfer characteristics of the IGZO TFTs under study.

      Table S1. Solubility of PAIs

      Table S2. Birefringence of PAIs

      Table S3. Transition temperatures of PAIs identified by the DMA

      Table S4. Summary of the GIWAXS peak positions

      Tables S5. Crystal data and structure refinement for amide-uDA

      Tables S6. Crystal data and structure refinement for imide-uDA

      Table S7. Bonding energies and geometric features of the 10 most stable dimeric structures for each of PAI(s-s), PAI(s-u), PAI(u-s), and PAI(u-u)

    • Supplementary Materials

      This PDF file includes:

      • Fig. S1. Synthetic route to uDA.
      • Fig. S2. 1H NMR spectra of the nitro intermediate 2 and uDA.
      • Fig. S3. 13C NMR spectra of the nitro intermediate 2 and uDA.
      • Fig. S4. FTIR spectra of the nitro intermediate 2 and uDA.
      • Fig. S5. Synthetic route to diacids.
      • Fig. S6. 1H NMR spectra of the diacids uDAc and sDAc.
      • Fig. S7. 13C NMR spectra of the diacids uDAc and sDAc.
      • Fig. S8. FTIR spectrum of uDAc.
      • Fig. S9. 1H-NMR spectra of PAIs.
      • Fig. S10. Photos of PAI films.
      • Fig. S11. UV-vis spectra of PAIs.
      • Fig. S12. TGA data of PAIs.
      • Fig. S13. DSC data of representative PAIs.
      • Fig. S14. DMA data of PAIs.
      • Fig. S15. TMA data of PAIs.
      • Fig. S16. 2D GIWAXS data of PAIs.
      • Fig. S17. 1D deconvoluted plot of the GIWAXS data in out-of-plane direction.
      • Fig. S18. 1D deconvoluted plot of the GIWAXS data in in-plane direction.
      • Fig. S19. A plot of CTE and π-π stacking distance versus β-relaxation temperature determined by the DMA.
      • Fig. S20. Synthetic route to model compound amide-uDA and imide-uDA.
      • Fig. S21. 1H NMR spectra of model compounds amide-uDA and imide-uDA.
      • Fig. S22. 13C NMR spectra of model compound amide-uDA and imide-uDA.
      • Fig. S23. FTIR spectra of model compound amide-uDA and imide-uDA.
      • Fig. S24. Chemical and crystal structures of model compound amide-uDA and imide-uDA.
      • Fig. S25. Ten most stable structures of PAI(s-s).
      • Fig. S26. Ten most stable structures of PAI(s-u).
      • Fig. S27. Ten most stable structures of PAI(u-s).
      • Fig. S28. Ten most stable structures of PAI(u-u).
      • Fig. S29. Transfer characteristics of the IGZO TFTs under study.
      • Table S1. Solubility of PAIs
      • Table S2. Birefringence of PAIs
      • Table S3. Transition temperatures of PAIs identified by the DMA
      • Table S4. Summary of the GIWAXS peak positions
      • Tables S5. Crystal data and structure refinement for amide-uDA
      • Tables S6. Crystal data and structure refinement for imide-uDA
      • Table S7. Bonding energies and geometric features of the 10 most stable dimeric structures for each of PAI(s-s), PAI(s-u), PAI(u-s), and PAI(u-u)

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