Mechanoresponsive Healable Metallo-Supramolecular Polymers

Transcription

1 Supporting Information Mechanoresponsive Healable Metallo-Supramolecular Polymers Guangning Hong, Huan Zhang, Yangju Lin, Yinjun Chen, Yuanze Xu, Wengui Weng* and Haiping Xia* Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian , P. R. China and 1

2 Table of Contents Materials Synthesis Figure S1 Figure S2 Figure S3 Figure S4 Figure S5 Figure S6 Figure S7 Table S1 Figure S8 Figure S9 Figure S10 Figure S11 Figure S12 Figure S13 Figure S14 Figure S15 Figure S16 Figure S17 Figure S18 Figure S19 Figure S20 Figure S21 Figure S22 Reference 2

3 Materials Synthesis Materials All reagents, chemicals, materials and solvents were obtained from Sinopharm, Sigma-Aldrich and Aladdin, and used as received unless otherwise noted. PTHF was dried at 70 o C under vacuum for 4 h before use. Spiropyran was also dried under vacuum before use. DMF, diisopropylanmine (DIPA) were distilled under N 2 over CaH 2 prior to use. All reactions were performed under N 2 atmosphere unless otherwise specified and all glassware was flame dried under vacuum before use. General Methods All reactions requiring inert gas were performed under N 2 atmosphere. NMR spectra were recorded on a 400 MHz Brucker Avance Ⅱ 400 spectrometer at 25 C using residual protonated solvent signals as internal standard. Gel permeation chromatography (GPC) data were calibrated against polystyrene standards and collected on a Waters 1515 equipped with a Waters 2414 Refractive Index Detector using THF as eluent. Synthesis of Spiropyran Diol (2-(8-(Hydroxymethyl)-3,3 -dimethyl-6-nitrospiro[chromene-2,2 -indolin]-1 -yl)e thanol) was synthesized according to the procedure published by Greg O Bryan. 1 Indolium bromide was converted to indole 5 by grinding in a mortar and pestle with potassium hydroxide in open air until a fine paste was obtained. This green chemistry approach resulted in near quantitative yield of indole 6 after extraction of the paste. Hydrolysis of 3-chloromethyl-5-nitrosalicylaldehyde 7 gave methylhydroxy substituted salicylaldehyde 8 in good yield after recrystallization from water. Spiropyran diol was prepared by condensation of 6 and 8 in refluxing 50% aqueous ethanol, which gave the product as a precipitate. The crude product was recrystallized from acetonitrile to afford the pure spiropyran. 1 H NMR (400 MHz; acetone-d6) δ(ppm): [8.23 & 8.05] (d, 2H, J = 3 Hz, Ar-H o-no 2 ), 7.18 (d, 1 H, J = 10.5 Hz, ArCH=CH-), 7.13 (m, 2 H, Ar-H m-nr 2 ), 6.83 (t, 1H, J = 7 Hz, Ar-H p-nr 2 ), 6.70 (d, 1 H, J = 7.5 Hz, Ar o-nr 2 ), 6.08 (d, 1 H, J = 10.5 Hz,-CH=CHAr), 4.43 (s, 2 H, 3

4 ArCH 2 OH), (m, 2 H, NCH 2 CH 2 OH), (m, 2H, NCH 2 CH 2 OH), [1.28 & 1.19] (s, 3 H, C(CH 3 ) 2 ). Thermogravimetric Analysis (TGA) Samples (100:0, 0:100 and the control) of about 8 mg were loaded onto a TA STD Q600 instrument under nitrogen atmosphere. The weight loss was recorded from room temperature to 700 C with a heating speed of 10 C min -1. Transition Electron Microscopy (TEM) TEM was carried out on a JEM-1400 microscope operated at a voltage of 120 KV. Samples were made by dropping dilute solutions of the metallo-supramolecular polymers on carbon coated copper grids followed by drying in vacuo. UV-vis Spectroscopy The UV-vis absorbance data were collected by use of a Cary 5000 UV spectrometer. Figure S1. Synthesis route of the spiropyran diol. 4

5 ppm Figure S2. 1 H NMR spectrum of spiropyran diol (400 MHz, acetone-d6) Figure S3. Synthesis route of the ligand macromolecule 2. 5

6 Retention Time / Min Figure S4. GPC trace of ligand macromolecule ppm ppm Figure S5. 1 H NMR spectrum of ligand macromolecule 2 (400 MHz, CDCl 3 ). 6

7 0:0 100:0 0:100 A B C Figure S6. Images of the metallo-supramolecular films (100:0 and 0:100) and the control 0:0 film. A: as prepared; B: irradiated with intense white light for 10 min; C: Fractured and retracted. Figure S7. Synthesis route of the macromolecule 3. Table S1. Effects of metal ion on the colour changes of polymers containing SP. 7

8 No. (1) (2) Light Vis UV Vis UV Image Composition 3 2 No. (3) (4) Light Vis UV Vis UV Image Composition 3+Eu 3+ 2+Eu 3+ No. (5) (6) Light Vis UV Vis UV Image Composition 3+Eu 3+ +PMDETA 2+Eu 3+ +PMDETA To test the effect of metal ions on the color changing of SP, a new macromolecule 3 containing SP units but no BTP moieties was synthesized. Macromolecule 3 was also synthesized via a polyurethane reaction method (Figure S7). The feed ratio was controlled to have similar SP contents in both 2 and mg polymer was first dissolved in 0.5 ml chloroform, then the color of the solution was checked under visible light or UV light. To the solution was added Eu(CF 3 SO 3 ) 3 (0.016 mmol), and the color of the solution was checked under visible light or UV light. Finally, to the solution was further added N,N,N',N',N''- 8

9 pentamethyldiethylenetriamine (PMDETA) (0.016 mmol), and the colour of the solution was again checked under visible light or UV light. The chloroform solution of 2 is light yellow under visible light, but it turned violet when irradiated with UV light (Table S1). The color change was reversible. Upon the addition of a small amount of Eu(CF 3 SO 3 ) 3, the solution quickly turned into yellow, which further turned into light brown after being subjected to UV irradiation, suggesting the possible complexation of Eu 3+ with MC moieties. Further addition of strongly coordinating PMDETA into the solution of 2 and Eu(CF 3 SO 3 ) 3 led to a solution exhibiting light induced color changing property similar to that of solution of 2. This indicates that the competitive binding from strong PMDETA ligand eliminate the effect of metal ion. Macromolecule 3 exhibited similar color changing behaviors. (a) (b) Figure S8. TEM of (a) 100:0 and (b) 0:100. Methanol was used to prepare solution of 100:0 for drop casting. The scale bar is 100 nm. 9

10 Figure S9. Snapshots during tensile test of the film made from simply blending of macromolecule 4, Zn 2+ salt and SP diol. (a) before deformation; (b) ε Eng = 600%.;(c) after failure. Macromolecule 4 containing BTP ligand but no SP was synthesized by the procedure reported elsewhere 2 and dry film was made by physically blending the polymer solution with SP diol as well as stoichiometric amount of Zn(OTf) 2 (the molar ratio of SP to BTP was kept the same as that in 100:0). The film was bleached to colorless by intense white light before stretching started. No colour variation was observed, implying that physically blended SP cannot be mechanically activated during tensile testing and the BTP-coordinated metal ions were unable to activate the mechanophores in the experimental time scale. 10

11 Intensity / a.u. Intensity / a.u. (a) % 30% 50% 70% 100% 300% 500% 700% 900% 1100% 1300% q / nm -1 (b) % 50% 100% 200% 300% 700% 500% 900% q / nm -1 Figure S10. SAXS data for a 100:0 film (a) and a 0:100 film (b) stretched at various engineering strains ε Eng as indicated in the legend. The curves are plotted in linear scale. 11

12 Absorbance / a.u. Absorbance / a.u :0 As prepared 0:0 White light 0:0 Fractured Wavelength / nm Figure S11. The UV-vis spectra of the control film 0: :0 As prepared 100:0 White light 100:0 Fractured Wavelength / nm Figure S12. The UV-vis spectra of the metallo-supramolecular film 100:0. 12

13 Absorbance / a.u. Absorbance / a.u :100 As prepared 0:100 White light 0:100 Fractured Wavelength / nm Figure S13. The UV-vis spectra of the metallo-supramolecular film 0: :0 100:0 0: Wavelength / nm Figure S14. The UV-vis spectra of the metallo-supramolecular films (100:0 and 0:100) and the control 0:0 film after being fractured and retraction. 13

14 (a) (b) (c) (d) Figure S15. Self-healing of Zn 2+ containing films (100:0) by dropping toluene. (a) 0 h, (b) 2 h, (c) 4 h, (d) 8 h. (a) (b) (c) (d) Figure S16. Self-healing of Eu 3+ containing films (0:100) by dropping toluene. (a) 0 h, (b) 2 h, (c) 4 h, (d) 8 h. 14

15 Eng / MPa Uncut Cut Chloroform Toluene Eng / % Figure S17. Stress-strain curves of self-healed Zn 2+ containing films (75:0). Cut films were treated with chloroform and toluene for 3 h and 8 h, respectively, before drying. Eng / MPa Uncut Cut Chloroform Toluene Eng / % Figure S18. Stress-strain curves of self-healed Eu 3+ containing films (0:75). Cut films were treated with chloroform and toluene for 3 h and 8 h, respectively, before drying. As evident by self-healing experiment of 0:100, Eu 3+ containing films are unable to self-heal by solvent treatment. With an aim to testing if more free BTP ligands can improve the self-healing property of the metallo-supramolecular films, two other samples of 75:0 (no Eu 3+ ions and 75% of the BTP ligands bind to Zn 2+ ions) and 0:75 (no Zn 2+ ions and 75% of the BTP ligands bind to Eu 3+ ions) were prepared and their self-healing behaviors were investigated. For 75:0 films, the stress - strain curves of the pristine sample and solvent treated 15

16 healed samples are exactly overlapped, which suggest that 75:0 films fully recover the mechanical properties with solvent treatments. The treated 0:75 films (Figure S17) however showed weak ability to self-heal. 75:0 and 0:75 films emerged similar self-healing properties with 100:0 and 0:100, indicating that presence of some certain amount of unbound ligands did little help to the self-healing of the metallo-supramolecular films containing Eu 3+ only. 16

17 (a) (b) (c) (d) Figure S19. Self-healing of Eu 3+ containing films (0:100) by dropping chloroform. (a) 0 h, (b) 1 h, (c) 3 h, (d) 8 h. (a) (b) (c) (d) Figure S20. Self-healing of Eu 3+ containing films (0:100) by dropping toluene. (a) 0 h, (b) 1 h, (c) 3 h, (d) 8 h. 17

18 Eng / MPa Mass / % Uncut Cut Colroform Toluene Eng / % Figure S21. Stress-strain curves of self-healed control films (0:0). Cut films were treated with either chloroform or toluene for 8 h followed by drying. Control sample showed little healing with solvent treatment, indicating that supramolecular interactions in the metallo-supramolecular are critical to the healing :0 100:0 0: Temperature / o C Figure S22. TGA traces of 100:0, 0:100 films and the control sample 0:0 with a heating rate of 10 C min -1. Reference 1. O Bryan, G.; Wong, B. M.; McElhanon, J. R. ACS Appl. Mater. Interf. 2010, 2, Yuan, J.; Fang, X.; Zhang, L.; Hong, G.; Lin, Y.; Zheng, Q.; Xu, Y.; Ruan, Y.; Weng, W.; Xia, H.; Chen, G. J. Mater. Chem. 2012, 22,