Research ArticleChemistry

Ionic liquid–based click-ionogels

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Science Advances  23 Aug 2019:
Vol. 5, no. 8, eaax0648
DOI: 10.1126/sciadv.aax0648
  • Fig. 1 Preparation of click-ionogels.

    (A) Composition of solutions A and B. (B) Preparation process and structural characterization of the click-ionogels. (C) Photographs showing that the click-ionogels can be molded in various shapes, including a circle (undyed), butterfly and leaves (dyed with methyl orange), and fish (dyed with methylene blue). Photo credit: Yongyuan Ren, Soochow University.

  • Fig. 2 Mechanical properties of click-ionogels.

    (A) Photographs demonstrating stretching and compression of click-ionogels. Mechanical properties of click-ionogel, IC gel, and CC gel; (B) tensile stress strain; (C) compressive stress-strain; and (D and E) cyclic tensile stress-strain fatigue tests. Photo credit: Yongyuan Ren, Soochow University.

  • Fig. 3 Mechanical properties of anti-freezing click-ionogels at low temperatures.

    (A) Photographs of a click-ionogel stretched above liquid nitrogen (about −50°C). (B) Tensile stress-strain and (C) compressive stress-strain curves for the click-ionogels from −40° to 0°C. (D) Storage moduli (G′) and loss moduli (G″) of hydrogels from −30°C to 100° and the click-ionogels from −80° to 180°C. (E) Dynamic scanning calorimetry (DSC) results of neat IL-BF4, dry polymer (drying the click-ionogel when the solvent is methanol), click-ionogel, and hydrogel between −100° and 20°C. The inset is the spectra enlargement of the dry polymer and click-ionogels. (F) Schematic hydrogen bonds between IL-BF4 and PEGDA segments. (G) 1H NMR spectra of IL-BF4, PEGDA, and IL-BF4/PEGDA. Photo credit: Yongyuan Ren, Soochow University.

  • Fig. 4 The mechanical performances of thermally stable click-ionogels.

    (A) Tensile stress and (B) compressive stress-strain curves for click-ionogels from 30° to 120°C. (C) Stability of the hydrogel and click-ionogels under long-term exposure to air at 50° and 250°C, respectively. (D) Thermal decomposition curves of the hydrogel and click-ionogels from 30° to 800°C.

  • Fig. 5 The electrochemical performances of click-ionogels.

    (A) Conductivity of click-ionogels from −60 to 200°C. (B) Decomposition voltage of the hydrogel and click-ionogels. (C) Scheme of TENG mechanism. The pictures and output currents of TENG under extreme conditions, such as (D and F) strain, (E and G) bent, and (H) low temperature and high temperature. Photo credit: Yongyuan Ren, Soochow University.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/8/eaax0648/DC1

    Fig. S1. Transmittance test of click-ionogels in the visible range.

    Fig. S2. 1H NMR characterization of BVIm-BF4.

    Fig. S3. 1H NMR characterization of IL-BF4.

    Fig. S4. 1H NMR characterization of poly(ionic liquid)s (PIL-BF4).

    Fig. S5. Preparation of ionic cross-linked gels.

    Fig. S6. Preparation of covalently cross-linked gels.

    Fig. S7. FT-IR spectra of precursor solution before and after the polymerization.

    Fig. S8. SSNMR spectra of PEGDA and click-ionogel.

    Fig. S9. Mechanism of Wijs method.

    Fig. S10. The storage moduli (G′) and loss moduli (G″) of ionic cross-linked CH3OH gels and ionic cross-linked IL-BF4 gels.

    Fig. S11. The interaction energy of polyacid-based BTCA with PIL-BF4 and IL-BF4 calculated via DFT, respectively.

    Fig. S12. Photos of PC organogels, EG organogels, and click-ionogels ignited by flames.

    Fig. S13. SEM microimages of click-ionogels before and after drying-out treatment.

    Table S1. The physicochemical properties of ILs with different cations and anions.

    Table S2. Gelation time of covalent cross-linking network gel using TEA as catalyst at 25°C.

    Table S3. The effect of the molar ratio of PETA to PEGDA on mechanical properties of click-ionogels.

    Table S4. Summary of the temperature range of different gels.

    Movie S1. Anti-freezing properties of click-ionogel.

    Movie S2. Gels ignited by flame.

  • Supplementary Materials

    The PDF file includes:

    • Fig. S1. Transmittance test of click-ionogels in the visible range.
    • Fig. S2. 1H NMR characterization of BVIm-BF4.
    • Fig. S3. 1H NMR characterization of IL-BF4.
    • Fig. S4. 1H NMR characterization of poly(ionic liquid)s (PIL-BF4).
    • Fig. S5. Preparation of ionic cross-linked gels.
    • Fig. S6. Preparation of covalently cross-linked gels.
    • Fig. S7. FT-IR spectra of precursor solution before and after the polymerization.
    • Fig. S8. SSNMR spectra of PEGDA and click-ionogel.
    • Fig. S9. Mechanism of Wijs method.
    • Fig. S10. The storage moduli (G′) and loss moduli (G″) of ionic cross-linked CH3OH gels and ionic cross-linked IL-BF4 gels.
    • Fig. S11. The interaction energy of polyacid-based BTCA with PIL-BF4 and IL-BF4 calculated via DFT, respectively.
    • Fig. S12. Photos of PC organogels, EG organogels, and click-ionogels ignited by flames.
    • Fig. S13. SEM microimages of click-ionogels before and after drying-out treatment.
    • Table S1. The physicochemical properties of ILs with different cations and anions.
    • Table S2. Gelation time of covalent cross-linking network gel using TEA as catalyst at 25°C.
    • Table S3. The effect of the molar ratio of PETA to PEGDA on mechanical properties of click-ionogels.
    • Table S4. Summary of the temperature range of different gels.

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    Other Supplementary Material for this manuscript includes the following:

    • Movie S1 (.mp4 format). Anti-freezing properties of click-ionogel.
    • Movie S2 (.mp4 format). Gels ignited by flame.

    Files in this Data Supplement:

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