Chem, Volume 3 Supplemental Information Dynamic Au-Thiolate Interaction Induced Rapid Self-Healing Nanocomposite Hydrogels with Remarkable Mechanical Behaviors Haili Qin, Tan Zhang, He-Nan Li, Huai-Ping Cong, Markus Antonietti, and Shu-Hong Yu
Supplemental Figures A B Figure S1. Morphology characterization and size distribution of used gold NPs, related to Figure 2. (A) TEM image of gold NPs deposited on the copper grid covered with ultrathin carbon film, showing well-dispersed and uniform particles. (B) Size distribution histograms of gold NPs, calculated to be 16 ± 5 nm. Figure S2. TEM image of Au/BACA nanocomposite, revealing well monodispersed property, related to Figure 2.
A B Figure S3. XRD pattern and swelling property of GNP hydrogels, related to Figure 2. (A) XRD pattern of dried GNP hydrogel showing diffraction peaks attributed to the gold nanoparticles incorporated in the hydrogel, and (B) Optical images showing the GNP hydrogel in original and swollen states at room temperature. Figure S4. Element mappings of the freeze-dried GNP hydrogel, related to Figure 2. The blue spots representing for gold atoms were dispersed uniformly over the whole picture, indicating the evenly distributed gold nanoparticles in the hydrogels.
A B C Figure S5. SEM images of freeze-dried GNP-0 and CP-15 hydrogels, related to Figure 2. SEM images of (A) freeze-dried GNP-0 hydrogel without gold NPs, (B) CP-15 with gold NPs physically incorporated in the network and (C) detailed analysis of pore size for CP-15 and GNP-15 hydrogels using mercury intrusion porosimeter. Both images and curves showed a broad pore distribution in the network when using organic crosslinking agents due to the irregular crosslinks in the polymerization, quite different from that when using our large and multifunctional crosslinking agents.
Figure S6. UV-Vis spectra and optical images of GNP hydrogel at different stretch, related to Figure 2. Figure S7. Optical images of as-prepared GNP hydrogels with varied contents of gold NPs, related to Figure 3.
A B C Figure S8. The effect of BACA and monomer concentrations and size of gold NP used on mechanical property of GNP hydrogels, related to Figure 3. The mechanical behaviors of our GNP hydrogels with the identical 0.75 mg/ml of gold NPs and various contents of (A) BACA and (B) monomer and (C) particle size. Based on the tensile stress-strain curves above, 0.5 mg of BACA and 800 mg of monomer and average size of 16 nm were chosen as the optimal conditions for the polymerization of our GNP hydrogels.
A B C Figure S9. Systematic analysis of the origin of enhancement on mechanics, related to Figure 3. (A) Optical images for preparation GNP-0 (etching) gel through an etching process. (B) SEM image of freeze-dried GNP-0 (etching) gel, inset: scheme for gel network without gold NP. (C) Stress-strain curves of GNP-15, GNP-0 (etching) and GNP-0 gels. Figure S10. Tensile stress-strain curves of GNP-15 hydrogel with different positions and types of a 1/3 notch, related to Figure 3.
Figure S11. Schematic illustration of the energy-dissipating mechanism of the damaged GNP hydrogels when stretched, related to Figure 3. Figure S12. Schematic mechanism for self-healing of GNP hydrogels under the irradiation of NIR laser (808 nm), related to Figure 4. The separated GNP hydrogel pieces were healed arising from the dynamic and reversible RS-Au bond induced surface reconstruction of hydrogel under the laser.
Figure S13. Control experiment of self-healing procedure without NIR irradiation, related to Figure 4. Optical images of GNP-20 hydrogel pieces in the self-healing procedure without NIR irradiation. Finally, no healing was observed. Figure S14. Schematic illustration for the healing mechanism between GNP-15 and GNP-0 hydrogel pieces, related to Figure 4. Figure S15. Schematic illustration for the healing mechanism between two GNP-0 hydrogel pieces with the aid of gold NPs, related to Figure 4.
Figure S16. Optical images for self-healing experiments of GNP hydrogels using heat as the external stimulus, related to Figure 4. The temperature of oven used was decided by the healing experiment under NIR irradiation, in which the gel was heated to nearly 45 o C. A B Figure S17. Control healing experiments of GNP-0 gels under various stimuli, related to Figure 4. Optical images for healing experiments of GNP-0 gels under the conditions of (a) NIR irradiation and (b) oven, and the temperature of oven used was decided by the healing experiment under NIR irradiation, in which the gel was heated to nearly 45 o C
Figure S18. DSC thermograms for GNP-0 and GNP-15 polymer network, related to Figure 4. A B C Figure S19. Stress-strain curves of the healed and pristine samples of GNP-5, GNP-10, and GNP-20, related to Figure 4. Stress-strain curves recorded in real-time on the tensile machine when loading for stretch of healed and as-prepared (a) GNP-5, (b) GNP-10, and (c) GNP-20 hydrogels.
Figure S20. Tensile stress-strain curves of healed sample of GNP-15 hydrogel pieces under NIR laser cycled for 10 times, related to Figure 4. Figure S21. Dependence of the power of NIR laser after penetration of GNP gels with thickness of gels performed, inset: optical images of GNP gels upon the NIR laser penetration, related to Figure 4.
Figure S22. Dependence of thermal responsiveness of GNP hydrogel with time under the irradiation of NIR laser and optical images for healing experiments at different time, related to Figure 4. Figure S23. Optical image for the real-time analysis of the opto-thermal performance, related to Figure 5.
Table S1. Comparison of self-healing performances of different hydrogels, related to Figure 4. Substance Healing mechanism Healing Healing Healing Ref. condition efficiency time Clay/G3-binder Non-covalent bonds Contact Horizontally _ S1 /vertically stable P(NaSS-co-MPTC) Ionic bonds Water 99% 24 h S2 PA6ACA Hydrogen bonds Low ph 66 ± 7% 24 h S3 solution DMAAm/TiNSs/ Photolatent Light Elongation 20 min S4 Laponite modulation (λ > 260 nm) of 500% βcd-ad-fc Host-guest Water 52% 24 h S5 interactions DNODN Hydrogen bonds and Contact Withstand S6 aromatic interactions shaking CEC-I-OSA-I-ADH Imine and PBS ~80% 3 h S7 acylhydrazone bonds solution GNP RS-Au bonds NIR laser (808 nm) 96% (Elongation of 2300%) 1 min Our work
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