Research ArticleMATERIALS SCIENCE

Solution-processed transparent ferroelectric nylon thin films

See allHide authors and affiliations

Science Advances  16 Aug 2019:
Vol. 5, no. 8, eaav3489
DOI: 10.1126/sciadv.aav3489
  • Fig. 1 Solution-processed ferroelectric nylon thin films.

    D-E hysteresis loop (top) and switching current (bottom) of (A) nylon-11 and (B) nylon-5, respectively. The insets show the respective chemical structures.

  • Fig. 2 Dissolution mechanism of nylons in the TFA:acetone mixture.

    (A) Boiling point (B. P.) and (B) vapor pressure (V. P.) of the solvent mixture of TFA:acetone as a function of acetone mole fraction (Xacetone). The inset shows the schematic of the interactions between TFA and acetone molecules for 50:50 mol % TFA:acetone. (C) 1H shift of the NMR (850.3 MHz at 298 K) spectra for different solvent mixtures of TFA:acetone-d6 as a function of acetone mole fraction. (D) 1H shift of the NMR (850.3 MHz at 298 K) spectra of nylon-11 solution for different solvent mixtures of TFA:acetone-d6 as a function of acetone mole fraction. The solubility region for nylons is marked in green. The insolubility region due to the shielding of the proton is marked in red. The inset shows the schematic of the shielding of TFA by acetone molecules for 75:25 mol % TFA:acetone.

  • Fig. 3 Transparent solution-processed nylon-11 thin films.

    Tapping mode AFM height image of the (A) conventionally spin-coated and (B) SQ thin films. (C) Ultraviolet-visible absorption as a function of wavelength on a double logarithmic scale of the conventionally spin-coated thin film and the SQ thin films. The dashed lines are the calculated absorbance using Eq. 1. The inset shows optical quality of the SQ thin films; the images of the logo of the Max Planck Institute for Polymer Research are taken through the SQ thin film (left) and the conventionally spin-coated films (right). Photo credit: Saleem Anwar, Max Planck Institute for Polymer Research. (D) Evolution of the roughness of the conventionally spin-coated and the SQ thin film upon variation in thicknesses. The RMS roughness is measured by AFM height topography, while calculated roughness is determined using optical absorption measurement. The calculated roughness agrees well with the experimental roughness obtained by AFM. The dashed lines are guide to the eye.

  • Fig. 4 Ferroelectric order in the SQ thin film of nylon-11.

    (A) WAXD patterns for the SQ thin film and the benchmark MQS film. The δ′ phase of nylon-11 has (001) peak at low q values and a broader peak at higher q values due to the superposition of (100)/(010) reflections. The solid lines show the deconvolution of the (100) and (010) reflections. The reported literature values for the δ′ phase are shown by black bars. (B) Room-temperature Fourier transform infrared (FTIR) spectra of the amide I and amide II bands for the SQ thin film and MQS film of nylon-11. (C) 1H magic angle spinning (MAS) and (D) 13C cross-polarization/MAS (CP/MAS) solid-state NMR spectra of the SQ thin film and MQS film. a.u., arbitrary units.

  • Fig. 5 Performance of nylon-11 ferroelectric thin film capacitors.

    (A) ±Pr (normalized to their initial value) as a function of the cumulative number of cycles. Nylon-11 ferroelectric capacitors outperform P(VDF-TrFE). (B) Data retention as a function of time measured for a period longer than a week. The inset shows the histogram of the Pr values obtained for thin film (240 nm) capacitors from different fabrication batches. The SQ thin films show a narrow distribution in Pr. (C) D-E hysteresis loops for various film thicknesses as a function of applied bias and electric field (inset). (D) The evolution of Ec and the yield of functional ferroelectric capacitors with film thickness. The dashed lines are a guide to eye.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/8/eaav3489/DC1

    Fig. S1. D-E hysteresis loop and switching current of MQS nylon-11.

    Fig. S2. 13C solution NMR spectra of the TFA:acetone-d6 mixture.

    Fig. S3. 1H solution NMR spectra of the TFA:acetone-d6 mixture.

    Fig. S4.1H-NMR DOSY measurement (850.3 MHz at 298 K) of nylon-11 solution in pure TFA (red spectrum) and 50:50 mol % mixture of TFA:acetone-d6 (black spectrum).

    Fig. S5. Haze as a function of film thickness of nylon-11.

    Fig. S6. DSC curves of SQ and MQS nylon-11 films.

    Fig. S7. Room-temperature FTIR spectra of the SQ thin film compared with MQS film of nylon-11.

    Fig. S8. WAXD pattern of the MQS film along the parallel and perpendicular to the stretch direction.

    Table S1. Literature overview of the crystalline phases of nylon-11 at room temperature.

    Table S2. Comparing the ferroelectric properties, Pr, and EC of nylon-11 and nylon-5 with those of PVDF and P(VDF-TrFE) reported in literature.

    References (3444)

  • Supplementary Materials

    This PDF file includes:

    • Fig. S1. D-E hysteresis loop and switching current of MQS nylon-11.
    • Fig. S2. 13C solution NMR spectra of the TFA:acetone-d6 mixture.
    • Fig. S3. 1H solution NMR spectra of the TFA:acetone-d6 mixture.
    • Fig. S4.1H-NMR DOSY measurement (850.3 MHz at 298 K) of nylon-11 solution in pure TFA (red spectrum) and 50:50 mol % mixture of TFA:acetone-d6 (black spectrum).
    • Fig. S5. Haze as a function of film thickness of nylon-11.
    • Fig. S6. DSC curves of SQ and MQS nylon-11 films.
    • Fig. S7. Room-temperature FTIR spectra of the SQ thin film compared with MQS film of nylon-11.
    • Fig. S8. WAXD pattern of the MQS film along the parallel and perpendicular to the stretch direction.
    • Table S1. Literature overview of the crystalline phases of nylon-11 at room temperature.
    • Table S2. Comparing the ferroelectric properties, Pr, and EC of nylon-11 and nylon-5 with those of PVDF and P(VDF-TrFE) reported in literature.
    • References (3444)

    Download PDF

    Files in this Data Supplement:

Stay Connected to Science Advances


Editor's Blog

Navigate This Article