Fe3+-, pH-, Thermoresponsive Supramolecular Hydrogel with

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Fe3+-, pH-, thermo-responsive supramolecular hydrogel with multi-shape memory effect Xiaoxia Le, Wei Lu, He Xiao, Li Wang, Chunxin Ma, Jiawei Zhang, Youju Huang, and Tao Chen ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.7b00169 • Publication Date (Web): 21 Feb 2017 Downloaded from http://pubs.acs.org on February 25, 2017

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ACS Applied Materials & Interfaces

Fe3+-, pH-, thermo-responsive supramolecular hydrogel with multi-shape memory effect

Xiaoxia Le, Wei Lu, He Xiao, Li Wang, Chunxin Ma, Jiawei Zhang*, Youju Huang, Tao Chen* Division of Polymer and Composite Materials, Key Laboratory of Marine Materials and Related Technologies, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo, 315201, P. R. China

Keywords: multi-responsive, multi-shape memory effect, tunable mechanical properties, supramolecular hydrogel, reversible switches

Abstract Poor, non-tunable mechanical properties as well as finite shape memory performance pose a barrier to shape memory hydrogels to realize practical applications. Here, a new shape memory hydrogel with tunable mechanical properties and multi-shape memory effect was presented. Three programmable reversible systems including PBA-diol ester bonds, AAc-Fe3+ and coil-helix transition of agar were applied to memorize temporary shapes and endow the hydrogel with outstanding multi-shape memory functionalities. Moreover, through changing the crosslinking densities, the mechanical properties of the as-prepared hydrogel can be adjusted.

1. INTRODUCTION As one kind of smart polymers, shape memory polymers (SMPs), which can fix temporary shapes and recover to original shapes under external stimuli1, 2, have aroused tremendous attention 1 ACS Paragon Plus Environment


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because of their promising application in textile, biomedical and so on3-5. Usually, there are two different crosslinks, one for keeping the permanent shape, and the other one is reversible, the formation and breakage of the reversible crosslinks contribute to the shape memory and shape recovery process. The traditional SMPs are usually polymers with thermo-responsiveness, in which the vitrification or crystallization of switching domains is the main driving force for shape memory. The follow-up development of SMPs are focused on changing external stimuli from direct heat to light, electricity, magnetic field by using photo-thermal effect, electro-thermal effect and magneto-thermal effect, which are actually still applying the morphology transformation of polymers through indirectly heat6-9. Due to the reversible and dynamical nature, reversible interactions10-14, such as hydrogen bonds15-17, host-guest recognition18, 19, metal-ligand coordination20-24 etc. are now utilized to realize shape memory performance25. By introducing reversible switches, SMPs, most of them are shape memory hydrogels (SMHs), can response to much more stimuli such as light19,

26

, heat16,

27

,

chemical28, 29, ultrasound30 and so forth, which broaden the way for memorizing temporary shapes and would expand the potential applications in other fields31. For example, Liu et al. have reported an unprecedented CO2-triggered shape memory behavior on the basis of diaminotriazine hydrogen bonds32. Willner et al. have developed DNA hydrogels with shape memory performance by regulating pH value33, 34. In addition, shape memory effect can be realized by applying host-guest interactions as temporary crosslinks 18, 35. Since the number of fixed temporary shapes normally has a great impact on the potential application, constructing multi-SMPs, which could keep two or more temporary shapes, has attracted broad attention. In our previous works, triple shape memory effect has been achieved by combining two non-interfering switchable interactions such as Alg-Ca2+ and PBA-diol ester bonds36, CS-Mn+ and Schiff base bonds37. However, there are still some challenges 2 ACS Paragon Plus Environment

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to develop supramolecular shape memory hydrogels with tunable mechanical strength as well as multi-shape memory effect for real promising applications. Herein, we present a novel Fe3+-, pH-, thermo-responsive hydrogel with tunable mechanical properties also multi-shape memory effect. Briefly, mechanical properties can be tuned by changing the crosslinking densities. Moreover, the coordination interactions between acrylic acid (AAc) and Fe3+ ions, the reversible PBA-diol ester bonds formed by phenylboronic acid groups (PBA) and adjacent hydroxyl groups of glucosamine, and the coil-helix transition of agar can all be employed to stabilize the temporary shapes to realize shape memory behavior. In addition, by combining the three reversible switches, programmable multi-shape memory effect can be realized. The presented strategy could enrich the construction as well as application of surpamolecular shape memory hydrogels.

2. EXPERIMENTAL SECTION 2.1 Materials. Agar powder (gel strength of 700-900 g/cm2), 3-Aminophenylboronic acid (APBA), D-(+)-glucosamine hydrochloride (GA), potassium carbonate (K2CO3), acryloyl chloride, acrylic acid (AAc), Glycine(≥99.0%), NaOH, FeCl3·6H2O, EDTA·2Na, rhodamine B (red dye) were purchased from Aladdin. Ammonium persulfate (APS), acrylamide (AAm), NaHCO3, methyl alcohol, methylene dichloride, tetrahydrofuran, ethyl acetate were commercially offered by Sinopharm Chemical Reagent Co., Ltd. Chemical reagents such as APS and AAm were used through recrystallization, and the others were used directly. 2.2 Synthesis of N-Acryloyl-3-aminophenylboronic Acid (AAPBA). AAPBA was synthesized in accordance with previous report and the synthetic route was shown in Scheme S138. 3-Aminophenylboronic acid (APBA) and NaHCO3 were dissolved in the mixed solution containing 3 ACS Paragon Plus Environment


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H2O and THF (v/v=2:1), then put into ice bath. After that, acryloyl chloride was cautiously added dropwise to the solution under intensive stirring over 1 h. Then the solution was stirred for another 2 h. The above solution was evaporated to obtain a crude product after being extracted with ethyl acetate. 80 mL H2O was added for recrystallization at 90 oC. Subsequently, the acicular crystals were filtered, washed and dried. The structure of AAPBA was characterized by the 400 MHz 1

HNMR (d6-DMSO) spectrum (Figure S1). 2.3 Synthesis of N-Acryloyl Glucosamine (AGA)39. According to previous report, AGA was

synthesized and the synthetic route was shown in Scheme S2. 5 g D-(+)-Glucosamine hydrochloride (GA) and 3.2 g potassium carbonate (K2CO3) were dissolved in 125 mL methanol. The mixed solution was cooled using an ice-salt bath. Acryloyl chloride was then added into above solution and reacted for 0.5 h under the rotational speed of 1500 r/min. The reaction was kept for another 4 h at 25 oC, and then was filtrated to move away solid impurity. After concentrating by rotary evaporation, white slurry was obtained. Column chromatography was then used for purification of the crude product with dichloromethane/methanol as eluent (ratio 4:1). White powder was obtained after dried overnight in 35 oC vacuum oven. The structure of AGA was confirmed by the 400 MHz 1HNMR (D2O) spectrum (Figure S2). 2.4 Preparation of Hydrogels. Agar powder (50 mg), AM monomers (450 mg), AAc monomers (15 wt% of AAm), AAPBA monomers (10 wt% of AAm) and AGA monomers (10 wt% of AAm) were first dissolved in 2.5 mL H2O at 90 oC for 10 min, the polymerization of monomers may not happen at this stage because of the absence of initiator. Then, APS solution (1 wt% of AAm) was added and oscillated rapidly. After that, the transparent, low-viscosity solution was transfused into corresponding molds, including a home-made mold consisting of two glass plates (2 mm) and one silica plate (1 mm or 2 mm), syringes with diameter of 1 cm. After cooling in refrigerator for 30 4 ACS Paragon Plus Environment

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min, agar formed the first physical-linked network by the agar helix bundles. Upon thermal initiation (60 oC, APS), all monomers were copolymerized. For better vision, the hydrogels were dyed with rhodamine B (red). 2.5 Preparation of Hydrogels with Tunable Mechanical Properties. The mechanical properties of the hydrogels were adjusted by changing the immersing time from 0 min to 20 min in Gly-NaOH buffer (pH = 10. 6) or Fe3+ solution (0.1 M) to obtain PBA-diol ester bonds and AAc-Fe3+ coordination. 2.6 Mechanical measurements. The tensile and compression tests were conducted on a tensile-compressive tester (Instron 5567). Samples with a dumbbell shape (length: 50 mm, width: 4 mm, thickness: 2 mm) were prepared for tensile testing. And the tensile tests were conducted at a constant rate of 50 mm/min. Samples with a cylinder shape (length: 1 cm, diameter: 1 cm) were prepared for compression tests (compression rate: 10% of original height/min, maximum compressive deformation: 95%). 2.7 Evaluation of Shape Memory Behaviors. All experiments were conducted at room temperature. Straight strip of hydrogels with size of 60 mm× 2 mm × 1 mm were first bended into temporary shapes, and then were soaked into Gly-NaOH buffer (pH=10.6) or Fe3+ solution (0.1 M) for a certain time to fix the temporary shapes. By submerging the gels in Gly solution (pH = 6) or 0.3 M EDTA solution, the shape recovery process was investigated. The thermal-induced shape memory phenomenon was performed by placing a hydrogel sample with temporary shape in an oven (10 min) and then cooling in a refrigerator (4 oC) for 6 min to memorize the temporary shapes. At last, the shape recovery process was achieved in hot water (60 oC).

3. RESULTS AND DISCUSSION 5 ACS Paragon Plus Environment


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The preparation of hydrogel with multi-shape memory effect is illustrated in Scheme 1. The first network was constructed by agar through heat-cool procedure, and the second network was formed by the copolymerization of all the monomers (Scheme 1A-1D). The coordination interactions between carboxylic acid and Fe3+, the reversible PBA-diol ester bonds and the coil-helix transition of agar could be employed for stabilizing temporary shapes and realizing shape memory performance.

Scheme 1. Schematic illustration of multi-responsive shape memory hydrogel on the basis of three different crosslinks, including AAc-Fe3+, dynamic PBA-diol ester bonds and helix-coil transition of agar. A-D) The preparation process of hydrogel. E-G) The reversible interactions can be formed in the as-prepared hydrogel, through which the hydrogel shows shape memory behavior. As shown in Figure 1, our as-prepared hydrogels (existing only agar helix as crosslinking points) exhibit outstanding mechanical properties compared with previously reported supramolecular shape memory hydrogels with similar water content18, 24, 29, 40. The hydrogels were tough enough to endure high-level deformations such as compression (Figure 1A), bending (Figure 1B), ordinary stretching 6 ACS Paragon Plus Environment

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(Figure 1C), knotted stretching (Figure 1D), twisted stretching (Figure 1E) without any obvious damage. In particular, the hydrogels will recover quickly after removing the external force. More specifically, the hydrogels could achieve a maximum tensile stress of 0.1 MPa with the elongation was almost 800%, and at compressive strain of 90%, the compressive stress can reach almost 6 MPa.

Figure 1. The prepared hydrogels are quite tough, flexible and can withstand different large deformations. A) Finger compression, B) Bending, C) Stretching ordinarily, D) Stretching after knotted, E) Stretching after twisted, F) Tensile stress-strain curves and G) Compressive stress-strain curves of the as-prepared hydrogels.

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As coordination interactions between carboxylic acid and Fe3+, PBA-diol ester bonds could be formed in our hydrogels, the mechanical properties of our hydrogels can be adjusted as expected. As shown in Figure 2, the impact of crosslinking density of two different crosslinks was investigated by altering the soaking time in Gly-NaOH buffer solution (to form crosslink1) or FeCl3 solution (to form crosslink2). With increasing immersing time in Gly-NaOH buffer solution, the tensile stress, tensile strain as well as elastic modulus (Figure 2A, Figure 2B) of the hydrogel enhance at first, and then decrease. The reason may be that most dynamic PBA-diol ester bonds were formed with increasing immersing time, which are more like covalent bonds at pH=10.6 and leads to the loss of energy dissipation capacity. As to the coordination interactions between carboxylic acid and Fe3+, the tensile stress was improved from 0.1 MPa to 0.28 MPa, then drops to 0.24 MPa with prolonging immersing time. In the meanwhile, the tensile strain also shows a similar trend, in which the maximum elongation can reach 1350%. A possible explanation to the above mechanical behavior is that the Fe3+ could form a mixture of mono-, bi-, and tridentates with AAc [41]

, the longer immersing time leading to more Fe3+ enter into the internal hydrogel and also form

more mono- or bidentates with AAc. As a result, for the hydrogels, the capacity of dissipating energy first rising and then has a downward trend. The strain range used to estimate the modulus is from 0% to 100% and the elastic modulus was increased with longer immersion time. Compared to hydrogels with crosslink1 (10 min immersing in Gly-NaOH buffer) and crosslink2 (10 min immersing in FeCl3 solution), a much tougher hydrogel with 0.3 MPa of tensile stress and 1050% of tensile strain can be obtained by combining both crosslink1 and crosslink2 (crosslink1+2, through soaking into Gly-NaOH buffer and FeCl3 solution for 10 min, respectively). As the two different reversible interactions coexisting in the network, they can have a synergistic effect for energy dissipation, thus the hydrogels show better mechanical properties comparing with single crosslinked 8 ACS Paragon Plus Environment

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hydrogels. Moreover, with the increasing of crosslink density, the compressive strength presents an uptrend (Figure 3F), and crosslink through AAc-Fe3+ seems to have more obvious enhancement to the compressive strength. It is worth mentioning that after compression test, all samples can recover to their initial status and the recovery rates are all greater than 90% (Figure S3 , Figure S4), which further elucidate that our hydrogels have good self-recovery performance.

Figure 2. Tunable mechanical properties of hydrogels with different cross-links. A) Tensile stress-strain curves and B) the variation of elasticity modulus of hydrogels with different crosslinking degree of dynamic PBA-diol ester bonds by immersing in Gly-NaOH buffer solution (0-20 min). C) Tensile stress-strain curves and D) the variation of elasticity modulus of hydrogels with different crosslinking degree of PAAc-Fe3+ by immersing in FeCl3 solution (0.1 M, 0-20 min).



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E) Tensile and F) compressive stress-strain curves of hydrogels with different crosslinks (each for 10 min). Our hydrogel networks contain three different kinds of functional groups as well as agar, among which PBA groups can integrate with glucosamine groups under basic condition to form dynamic PBA-diol ester bonds, carboxylate groups can chelate Fe3+, and agar can realize coil-helix transition upon changing the temperature42, 43. All the reversible crosslinks could be employed to keep the temporary shapes of the hydrogel, and achieve shape memory performance (Figure S6 shows the shape fixity ratios and shape recovery ratios). Figure 3 shows that a straight strip of hydrogel was shaped into a heart shape and then immersed into FeCl3 solution (0.1 M). Through the AAc-Fe3+ crosslinks, the final temporary heart shape could be well fixed. After immersing into EDTA (0.3 M) solution, Fe3+ will be extracted by EDTA, the hydrogel can slowly recover (Figure S7A, Figure S7B, Figure S7C). In addition, temporary shapes can also be fixed by the formation of dynamic PBA-diol ester bonds (Figure 3C, Figure S7D, Figure S7E, Figure S7F). The hydrogel with spiral temporary shape was put into Gly-NaOH buffer solution (pH=10.6) for 10 min. Once the fixed shapes were immersed into Gly solution (pH=6), the recovery to the original state can be achieved through the disassociation of PBA-diol ester bonds (Figure S7D, Figure S7E, Figure S7F). In addition, the coil-helix transition of agar upon temperature changing can also be utilized to accomplish shape memory performance (Figure 3D, Figure S7G, Figure S7H, Figure S7I). A straight strip of hydrogel was first put into an oven (60 oC) for 10 min to become soft and could be shaped into many shapes. Then the hydrogel with a deformed “N” shape was cooled in the refrigerator (4 oC) to induce the formation of helix structure of agar, and the temporary shapes could be memorized. After putting into hot water (60 oC), the hydrogel could recover to the initial shape in a short time as agar transfer to the coil state. 10 ACS Paragon Plus Environment

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Figure 3. Dual shape memory effect based on Fe3+, pH and thermal, respectively. (A-B) Heart shape can be memorized and recovered through the chelation and damage between carboxylate and Fe3+. (A-C) On the basis of dynamic PBA-diol ester bonds, the hydrogel can memorize spiral shape and recover to permanent shape. (A-D) Attributed to agar’s responsiveness of temperatures, the hydrogel can get temporary “N” shape fixed as well as recover to original shape.

A multi-shape memory material which could remember more than two temporary shapes could meet more specific and complicated applications, but not easy to realize. As our hydrogel could respond to three different stimuli, which urge us to further explore the multi-shape memory effect. As shown in Figure 4, hydrogel was first put into an oven at 60 oC for 10 min, the hydrogel was bent and put into a refrigerator at 4 oC to fix temporary shape I. Then the hydrogel was shaped again and immersed into Gly-NaOH buffer solution (pH=10.6) to fix temporary shape II, finally the hydrogel was bent into a “W” shape and stabilized by the complexation of AAc and Fe3+. The recovery of “W” shape hydrogel from temporary shape Ⅲ to temporary shape Ⅱ was conducted by immersing in the competition ligand solution (EDTA, 0.3 M) to break the AAc-Fe3+ interaction 11 ACS Paragon Plus Environment


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(Figure S8B). By destroying the PBA-diol ester bonds in acidic condition, the hydrogel can recover to temporary shape I (Figure S8C). It will finally become straight because of the helix-coil transition of agar (Figure S8D). Here, we would like to point out that the programmable steps cannot be changed for the following reasons: firstly, Fe3+ would be deposited in Gly-NaOH buffer (pH = 10.6), therefore gels was first immersed into Gly-NaOH buffer; secondly, all the reversible switches may be damaged by heating, so heat was put at last during the recovery process. In addition, the strategy introduced here selects three different reversible interactions, by which multi-shape memory properties in a programmatic way can be realized and the procedure could also be repeated.

Figure 4. Fe3+-, pH-, thermo-induced multi-shape memory effect. (A-B) Temporary shape I was fixed by coil-helix transition of agar upon changing the temperature. (B-C) The crosslinks of dynamic PBA-diol ester bonds can be applied for memorizing temporary shape Ⅱ. (C-D) Through the chelation between Fe3+ and carboxylic groups, temporary shape Ⅲ can be fixed. (E) The mechanism of programmed multi-shape memory process.

CONCLUSIONS 12 ACS Paragon Plus Environment

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In conclusion, through integrating various reversible interactions, we present a novel supramolecular hydrogel with both tunable mechanical properties and multi-shape memory effect. The hydrogel contains a physically crosslinked agar network and a supramolecular network crosslinked by reversible PBA-diol ester bonds and AAc-Fe3+ coordination. The hydrogel exhibits good mechanical properties and the mechanical performance could be tuned by adjusting the crosslinking density. The coil-helix transition of agar, PBA-diol ester bonds and AAc-Fe3+ coordination could all be applied to fix temporary shapes and realize dual shape memory behavior. Furthermore, multi-shape memory effect can be realized through programmable integration of three reversible interactions. The presented strategy could broaden the list of shape memory hydrogels and promote the design of novel shape memory systems for real applications.

ASSOCIATED CONTENT Supporting Information The Supporting Information is available free of charge on the ACS Publications website at DOI: ******. The synthetic route of AAPBA; 1H NMR (d6-DMSO) spectrum of AAPBA; the synthetic route of AGA; 1H NMR (D2O) spectrum of AGA; the photographs of compressive tests; the graph of recovery rate of different samples after being compressed; the water contents of hydrogels with different crosslinks; the shape fixity ratios and shape recovery ratios of three reversible interactions; the pictures of dual-shape memory and shape recovery process; the recovery of multi-shape memory effect (PDF)



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AUTHOR INFORMATION Corresponding Authors *E-mail: [email protected] (J-W. Z.). *E-mail:[email protected] (T. C.). Notes The authors declare no competing financial interest.

ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (21644009), Natural science foundation of Zhejiang (LY17B040003, LY17B040004), Key Research Program of Frontier Science, Chinese Academy of Sciences (QYZDB-SSW-SLH036), Ningbo Science and Technology Bureau (2016C50009), China Postdoctoral Science Foundation (2016M590556), and Youth Innovation Promotion Association of Chinese Academy of Sciences (2017337, 2016268).

REFERENCES (1) Habault, D.; Zhang, H.; Zhao, Y. Light-Triggered Self-Healing and Shape-Memory Polymers. Chem. Soc. Rev. 2013, 42, 7244-7256. (2) Zhao, Q.; Qi, H.; Xie, T. Recent Progress in Shape Memory Polymer: New Behavior, Enabling Materials, and Mechanistic Understanding. Prog. Polym. Sci. 2015, 49-50, 79-120. (3) Liu, C.; Qin, H.; Mather, P. Review of Progress in Shape-Memory Polymers. J. Mater. Chem. 2007, 17, 1543-1558. (4) Small, W.; Singhal, P.; Wilson, T.; Maitland, D. Biomedical Applications of Thermally Activated 14 ACS Paragon Plus Environment

Page 15 of 19

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Shape Memory Polymers. J. Mater. Chem. 2010, 20, 3356-3366. (5) Sun, L.; Huang, W.; Ding, Z.; Zhao, Y.; Wang, C.; Purnawali, H.; Tang, C. Stimulus-Responsive Shape Memory Materials: A Review. Mater. Des. 2012, 33, 577-640. (6) Zhang, H.; Zhao, Y. Polymers with Dual Light-Triggered Functions of Shape Memory and Healing Using Gold Nanoparticles. ACS Appl. Mater. Interfaces 2013, 5, 13069-13075. (7) Lee, S.; Jung, J.; Oh, I. 3D Networked Graphene-Ferromagnetic Hybrids for Fast Shape Memory Polymers with Enhanced Mechanical Stiffness and Thermal Conductivity. Small 2014, 10, 3880-3886. (8) Schmidt, A. Electromagnetic Activation of Shape Memory Polymer Networks Containing Magnetic Nanoparticles. Macromol. Rapid Commun. 2006, 27, 1168-1172. (9) Liu, Y.; Lv, H.; Lan,X.; Leng, J.; Du, S. Review of Electro-Active Shape-Memory Polymer Composite. Compos. Sci. Technol. 2009, 69, 2064-2068. (10) Ma, C.; Li, T.; Zhao, Q.; Yang, X.; Wu, J.; Luo, Y.; Xie, T. Supramolecular Lego Assembly Towards Three-Dimensional Multi-Responsive Hydrogels. Adv. Mater. 2014, 26, 5665-5669. (11) Liu, K.; Kang, Y.; Wang, Z.; Zhang, X. 25th Anniversary Article: Reversible and Adaptive Functional Supramolecular Materials: “Noncovalent Interaction” Matters. Adv. Mater. 2013, 25, 5530-5548. (12) Yan, X.; Wang, F.; Zheng, B.; Huang, F. Stimuli-Responsive Supramolecular Polymeric Materials. Chem. Soc. Rev. 2012, 41, 6042-6065. (13) He, L.; Szopinski, D.; Wu, Y.; Luinstra, G.; Theato, P. Toward Self-Healing Hydrogels Using One-Pot Thiol-Ene Click and Borax-Diol Chemistry. ACS Macro Lett. 2015, 7, 673-678. (14) Meng, H.; Zheng, J.; Wen, X.; Cai, Z.; Zhang, J.; Chen, T. pH- and Sugar-Induced Shape Memory Hydrogel Based on Reversible Phenylboronic Acid–Diol Ester Bonds. Macromol. Rapid 15 ACS Paragon Plus Environment


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Commun. 2015, 36, 533-537. (15) Chen, H.; Li, Y.; Tao, G.; Wang, L.; Zhou, S. Thermo- and Water-Induced Shape Memory Poly(vinyl alcohol) Supramolecular Networks Crosslinked by Self-Complementary Quadruple Hydrogen Bonding. Polym. Chem. 2016, 7, 6637-6644. (16) Chen, Y.; Peng, L.; Liu, T.; Wang, Y.; Shi, S.; Wang, H. Poly(vinyl alcohol)−Tannic Acid Hydrogels with Excellent Mechanical Properties and Shape Memory Behaviors. ACS Appl. Mater. Interfaces 2016, 8, 27199-27206. (17) Hu, X.; Vatankhah-Varnoosfaderani, M.; Zhou, J.; Li, Q.; Sheiko, S. Weak Hydrogen Bonding Enables Hard, Strong, Tough, and Elastic Hydrogels. Adv. Mater. 2015, 27, 6899-6905. (18) Miyamae, K.; Nakahata, M.; Takashima, Y.; Harada, A. Self-Healing, Expansion–Contraction, and Shape-Memory Properties of a Preorganized Supramolecular Hydrogel through Host–Guest Interactions. Angew. Chem., Int. Ed. 2015, 54, 8984-8987. (19) Pan, M.; Yuan, Q.; Gong, X.; Zhang, S.; Li, B. A Tri-Stimuli-Responsive Shape-Memory Material Using Host–Guest Interactions as Molecular Switches. Macromol. Rapid Commun. 2016, 37, 433-438. (20) Fan, Y.; Zhou, W.; Yasin, A.; Li, H.; Yang, H. Dual-Responsive Shape Memory Hydrogels with Novel Thermoplasticity Based on A Hydrophobically Modified Polyampholyte. Soft Matter 2015, 11, 4218-4225. (21) Xu, B.; Li, Y.; Gao, F.; Zhai, X.; Sun, M.; Lu, W.; Cao, Z.; Liu, W. High Strength Multifunctional Multiwalled Hydrogel Tubes: Ion-Triggered Shape Memory, Antibacterial, and Anti-Inflammatory Efficacies. ACS Appl. Mater. Interfaces 2015, 7, 16865-16872. (22) Ren, Z.; Zhang, Y.; Li, Y.; Xu, B.; Liu, W. Hydrogen Bonded and Ionically Crosslinked High Strength Hydrogels Exhibiting Ca2+-Triggered Shape Memory Properties and Volume Shrinkage for 16 ACS Paragon Plus Environment

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Cell Detachment. J. Mater. Chem. B 2015, 3, 6347-6354. (23) Han, Y.; Bai, T.; Liu, Y.; Zhai, X.; Liu, W. Zinc Ion Uniquely Induced Triple Shape Memory Effect of Dipole–Dipole Reinforced Ultra-High Strength Hydrogels. Macromol. Rapid Commun. 2012, 33, 225-231. (24) Meng, H. Xiao, P.; Gu, J.; Wen, X.; Xu, J.; Zhao, C.; Zhang, J.; Chen, T. Self-Healable Macro-/Microscopic Shape Memory Hydrogels Based on Supramolecular Interactions. Chem. Commun. 2014, 50, 12277-12280. (25) Lu, W.; Le, X.; Zhang, J.; Huang, Y.; Chen, T. Supramolecular Shape Memory Hydrogels: A New Bridge Between Stimuli-responsive Polymers and Supramolecular Chemistry. Chem. Soc. Rev. 2017, DOI: 10.1039/C6CS00754F. (26) Feng, W.; Zhou, W.; Zhang, S.; Fan, Y.; Yasin, A.; Yang, H. UV-Controlled Shape Memory Hydrogels Triggered by Photoacid Generator. RSC Adv. 2015, 5, 81784-81789. (27) Hao, J.; Weiss, R. Mechanically Tough, Thermally Activated Shape Memory Hydrogels. ACS Macro Lett. 2013, 2, 86-89. (28) Zhao, T.; Tan, M.; Cui, Y.; Deng, C.; Huang, H.; Guo, M. Reactive Macromolecular Micelle Crosslinked Highly Elastic Hydrogel with Water-Triggered Shape-Memory Behaviour. Polym. Chem. 2014, 5, 4965-4973. (29) Yasin, A.; Li, H.; Lu, Z.; Rehman, S.; Siddiqb, M.; Yang, H. A Shape Memory Hydrogel Induced by The Interactions Between Metal Ions and Phosphate. Soft Matter 2014, 10, 972-977. (30) Li, G.; Yan, Q.; Xia, H.; Zhao, Y. Therapeutic-Ultrasound-Triggered Shape Memory of a Melamine-Enhanced Poly(vinyl alcohol) Physical Hydrogel. ACS Appl. Mater. Interfaces 2015, 7, 12067-12073. (31) Chan, B.; Low, Z.; Heng, S.; Chan, S.; Owh, C.; Loh, X. Recent Advances in Shape Memory 17 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 18 of 19

Soft Materials for Biomedical Applications. ACS Appl. Mater. Interfaces 2016, 8, 10070-10087. (32) Xu, B.; Zhang, Y.; Liu, W. Hydrogen-Bonding Toughened Hydrogels and Emerging CO2 -Responsive Shape Memory Effect. Macromol. Rapid Commun. 2015, 36, 1585-1591. (33) Hu, Y.; Guo, W.; Kahn, J.; Aleman-Garcia, M.; Willner, I. A Shape-Memory DNA-Based Hydrogel Exhibiting Two Internal Memories. Angew. Chem., Int. Ed. 2016, 55, 4210-4214. (34) Lu, C.; Guo, W.; Hu, Y.; Qi, X.; Willner, I. Multitriggered Shape-Memory Acrylamide−DNA Hydrogels. J. Am. Chem. Soc. 2015, 137, 15723-15731. (35) Yasin, A.; Zhou, W.; Yang, H.; Li, H.; Chen, Y.; Zhang, X. Shape Memory Hydrogel Based on a Hydrophobically-Modifi ed Polyacrylamide (HMPAM)/α-CD Mixture via a Host-Guest Approach. Macromol. Rapid Commun. 2015, 36, 845-851. (36) Le, X.; Lu, W.; Zheng, J.; Tong, D.; Zhao, N.; Ma, C.; Xiao, H.; Zhang, J.; Huang, Y.; Chen, T. Stretchable Supramolecular Hydrogels with Triple Shape Memory Effect. Chem. Sci. 2016, 7, 6715-6720. (37) Xiao, H.; Lu, W.; Le, X.; Ma, C.; Li, Z.; Zheng, J.; Zhang, J.; Huang, Y.; Chen, T. A Multi-Responsive Hydrogel with A Triple Shape Memory Effect Based on Reversible Switches. Chem. Commun. 2016, 52, 13292-13295. (38) Guo, Q.; Wu, Z.; Zhang, X.; Sun, L.; Li, C. Phenylboronate-Diol Crosslinked Glycopolymeric Nanocarriers for Insulin Delivery at Physiological pH. Soft Matter 2014, 10, 911-920. (39) Xue, L.; Lyu, Z.; Shi, X.; Tang, Z.; Chen, G.; Chen, H. Fast and Green Synthesis of A Smart Glyco-Surface via Aqueous Single Electron Transfer-Living Radical Polymerization. Macromol. Chem. Phys. 2014, 215, 1491-1497. (40) Nan, W.; Wang, W.; Gao, H.; Liu, W. Fabrication of A Shape Memory Hydrogel Based On Imidazole-zinc Ion Coordination For Potential Cell-encapsulating Tubular Scaffold Application. 18 ACS Paragon Plus Environment

Page 19 of 19

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Soft Matter 2013, 9, 132-137. (41) Lin, P.; Ma, S.; Wang, X.; Zhou, F. Molecularly Engineered Dual-Crosslinked Hydrogel with Ultrahigh Mechanical Strength, Toughness, and Good Self-Recovery Adv. Mater. 2015, 27, 2054-2059. (42) Chen, Q.; Zhu, L.; Zhao, C.; Wang, Q.; Zheng, J. A Robust, One-Pot Synthesis of Highly Mechanical and Recoverable Double Network Hydrogels Using Thermoreversible Sol-Gel Polysaccharide. Adv. Mater. 2013, 25, 4171-4176. (43) Chen, Q.; Zhu, L.; Chen, H.; Yan, H.; Huang, L.; Yang, J.; Zheng, J. A Novel Design Strategy for Fully Physically Linked Double Network Hydrogels with Tough, Fatigue Resistant, and Self-Healing Properties. Adv. Funct. Mater. 2015, 25, 1598-1607.

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Fe3+-, pH-, Thermoresponsive Supramolecular Hydrogel with

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