A fascinating metallo-supramolecular polymer network with thermal/magnetic/light-responsive shape-memory effects anchored by Fe 3 O 4 nanoparticles

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1 Supporting Information: A fascinating metallo-supramolecular polymer network with thermal/magnetic/light-responsive shape-memory effects anchored by Fe 3 O 4 nanoparticles Lan Du, Zhi-Yuan Xu, Cheng-Jie Fan, Gang Xiang, Ke-Ke Yang* and Yu-Zhong Wang Measurement X-ray diffraction (XRD). The Fe 3 O 4 NPs were analyzed on a Philips X Pert Pro diffractometer over the 2 θ range from at rate of 2.5 /min, using Cu-Kα radiation (λ = Å). Vibrating sample magnetometer (VSM). The magnetic properties of the Fe 3 O 4 NPs were measured with a Vibrating Sample Magnetometer at room temperature. Dynamic light scattering (DLS). The averaged diameter and distribution of the Fe 3 O 4 NPs were determined by dynamic light scattering (DLS) on a Brookhaven model BI-200SM spectrometer (Brookhaven Instruments CO., USA) equipped with a 9000AT correlator using an Innova 304 He-Ne laser (1 W, λ=532 nm). Scanning electron microscopy (SEM). The fracture surfaces of the Fe 3 O 4 NPs were observed by scanning electron microscopy (SEM, Philips, Netherlands) with using a 10 kv accelerating voltage. Methods S1: Characterization of Fe 3 O 4 nanoparticles. The oleic acid group coated Fe 3 O 4 nanoparticles were analyzed according to their physical and

2 magnetic properties. The results of XRD measurement showed that the main component of samples was Fe 3 O 4 (Figure 1S). According to the Debye-Scherrer equation, we could calculate the mean particle diameters with the XRD pattern as follow equation. D C = Kλ bcosθ (1) In the equation, θ is the angle at where the peak is exist, λ is the X-ray wave length ( Å), K is a constant, about 0.89 for magnetite and b is the width of the XRD peak at half height. And the value calculated is about 12 nm by Debye-Scherrer equation. In Figure 1S(b), the magnetism test reveals that the Fe 3 O 4 NP have perfect superparamagnetism. Dynamic Light Scattering (DLS) was employed to measure the nanoparticle size and its distribution, as showed in Figure 1S(c), the mean diameter of Fe 3 O 4 NP is about 20 nm in a narrow distribution, this value is slightly larger than what determined by XRD. Figure 1S(d) displays the SEM images of Fe 3 O 4 nanoparticles. Figure 1S. a) XRD pattern of the oleic acid group coated Fe 3 O 4 nanoparticles. b) Magnetization hysteresis curve of the oleic acid group coated Fe 3 O 4 nanoparticles under magnetic field at 300K. c) Particle size distribution of the oleic acid group coated Fe 3 O 4 nanoparticles as number percent (%).d)

3 SEM micrographs for Fe 3 O 4 nanoparticles. S2: The detailed calculation method of the molecular weight of the pre-polymer by 1 H-NMR and UV-Vis spectra For 1 H-NMR, the molecular weight of the HO-PCL-OH is calculated by the following formulas: M n = 114 I 4.06 I (2) I 4.06 and I 3.70 indicate the peak intensities of δh a and δh b in Figure 1. The molecular weight of the PCL-DA for 1 H-NMR is calculated by following formulas: M n = [( I 3.98 I ) ] (3) I and I 3.98 indicate the peak intensities of δh a and δh e in Figure , 170 and 138 are the molecular weights of the repeat unit, HDI and terminal group, respectively. The molecular weight of the PCL-DA can also be calculated from UV-vis spectra. Firstly, we need to determine the absorbance peak of different concentrations of dopamine hydrochloride in DMF (mol/ml) at 283 nm and obtain a standard curve of the content of catechol group and absorbance by Beer-Lambert Law. Then, we need to determine the absorbance peak of a known concentration PCL-DA in DMF (g/ml) at 283nm to get the content of catechol group in a known concentrations PCL-DA. Finally, the molecular weight of the PCL-DA can be calculated. S3: The storage modulus-temperature curves of the PCL-based samples.

4 Figure 2S. The storage modulus-temperature curves of the PCL 2.8K -based samples PCL 4.9K -based samples (b) and PCL 6.1K -based samples (c). (a), S4: One-way and two-way shape memory properties. One-way and two-way shape memory properties of PCL-DA-Fe 3 O 4 networks were evaluated using shape memory cycles (SMC) tested with a DMA Q800 (TA Instruments, USA) in a controlled force mode. The one-way shape memory cycle considered the T c and T m of the sample. The two key temperature of the program were T low and T high which were below T c and T m + 25 C respectively. In the programming step, the test sample is heated up to a temperature T high which is above the switching temperature for 10 min to make sure the sample is completely melted. Now, the strain was ε p (N-1).

5 Then, the sample is stretched to the maximum strain (ε m (N)) at T high. After that, the sample is cooled to a temperature (T low ) which is below T c under constant load. The purpose of this step is to fix the temporary shape completely. Kept about 5 min, and the load was removed. The strain was ε f (N). Finally, the sample was reheated, it contracts and the recovered strain was ε p (N). Then, the cycle begins again. The important quantities to be determined for describing the shape-memory properties of the material at strain were the strain recovery rate R r and the strain fixity rate R f. These can be determined according to follow equations from the strain values. R r (N) = ε m(n) ε p (N) 100% (4) ε m (N) ε p (N 1) R f (N) = ε f(n) ε p (N 1) 100% (5) ε m (N) ε p (N 1) In contrast, the two-way shape memory cycle contained a deformation step and a recovery step under a constant non-zero load. In detail, the process included the following four steps: Firstly, the samples were also kept at a temperature (T high ) which is about T m + 25 C for 10 min to make sure the sample is completely melted. Then, the specimen was strained at a constant stress,and maintaining the stress and temperature constant for 15 min. The strain of the sample was ε high (N). Then, the deformed and loaded specimen was then cooled down at 10 C/min to the low temperature which below T c, and maintaining the stress and temperature constant for 10 min. The strain of the sample was ε low (N). Finally, the sample was then reheated to T high at a rate of 10 C/min, and maintaining the stress

6 and temperature constant for 10 min. The strain of the sample was ε high (N+1). This shape memory cycle was performed repeatedly by cooling and heating under a constant load. The important characteristics of the two-way shape memory are the actuation magnitude (R act (σ)) which is the strain increment during cooling and the strain recovery magnitude (R rec ). Both were calculated from the observable sample strain for a two-way shape memory behavior as follows. R act (σ) = ε low ε high (6) R rec (N) = ε low (N) ε high (N+1) 100% (7) ε low (N) ε high (N) When the applied stress during actuation increased, the strain increment also increased. Take PCL 2.8K -DA-15%Fe 3 O 4 as an example, Figure 2S reveal that increasing the applied stress from 0.32 to 0.80 MPa raised the strain increment from 17.51% to 57.06%. According to the curve of strain-temperature, we choose 0.48 MPa as the experimental standard. Because when the stress raised to 0.48 MPa, the strain increment reach to a relatively high value (26.02%). And compared to higher stress, the strain recovery is better. Figure 3S. Strain-temperature protocol for PCL 2.8K -DA-15%Fe 3 O 4 at different constant stresses σ, 0.32 MPa, 0.48 MPa, 0.64 MPa, 0.80 MPa.

7 S5: The magnetocaloric effect and photothermal effect of the Fe 3 O 4 NPs and the networks Figure 4S. The magnetocaloric effect of the Fe 3 O 4 NPs(i) and the PCL-DA-Fe 3 O 4 networks with 5% (iv), 15% (iii) and 30% (ii) Fe 3 O 4 contents Figure 5S. (a).the photothermal effect of the PCL 4.9K -DA-15%Fe 3 O 4 networks with different distances between sample and light source: (i) 15 cm, (ii) 20 cm, (iii) 25 cm; (b), (c). The photothermal effect of the Fe 3 O 4 NPs (i) and the PCL-DA-Fe 3 O 4 networks with 0% (ii) 5% (iii), 15% (iv) and 30% (v) Fe 3 O 4 contents with the distance of 20 cm S6: Evaluation of magnetic-responsive two-way shape-memory effect.

8 The inductive heating was accomplished by putting the sample in an alternating magnetic field at a frequency of ƒ=300 khz. This experimental device allows variation of the magnetic field strength H in the center of the coil between 0 and 4.5 ka/m by adjusting the power of a high-frequency generator (Duolin electrical, Chengdu, China, Modol No. HGP-6A). The investigation of magnetic-responsive two-way shape-memory effect: at first, a straight sample with 100 g weight was heated to 80 ºC which result in the sample elongated. Then, after the sample with weight was removed to room temperature to cool for a while, the sample elongation again because of crystallization induced elongation. Finally, removing the sample to an alternating magnetic field, we could find that the sample contract with the alternating magnetic field on and the sample elongate with the alternating magnetic field off. S7: Evaluation of the light-responsive two-way shape-memory effect. The inductive heating was accomplished by putting the sample in a near-infrared light. The investigation of light-responsive two-way shape-memory effect: at first, a straight sample with 100 g weight was heated to 80 ºC which result in the sample elongated. Then, after the sample with weight was removed to room temperature to cool for a while, the sample elongation again because of crystallization induced elongation. Finally, using near-infrared laser to exposure the sample from 20 cm, we could find that the sample contract with the laser on and the sample elongate with the laser off. And the power density delivered to the sample was about 9.2 mw/mm 2 (Lasever Inc. Ningbo, China, Modol NO. LSR808H-FC-7.5W) S8: The healing behavior of the pure chemically cross-linked PCL film.

9 The tensile tests were carried out to evaluate the healing ability of the pure chemically cross-linked PCL film. Three strips of samples were be chosen, i.e., a non-damaged strip, a damaged strip without any treatment and a damaged strip healed at 100 C for 10 h. Figure 6S. Typical engineering stress-strain curve for the pure chemically cross-linked PCL film in original state (a), just damaged (b) and healed at 100 C for 10h (c). S9: The healing behavior of the PCL 4.9 K-DA-15%Fe 3 O 4 network at 80 C. The tensile tests were carried out to evaluate the healing ability of the PCL 4.9 K-DA-15%Fe 3 O 4 network at 80 C. Figure 7S. Typical engineering stress-strain curve for the PCL 4.9 K-DA-15%Fe 3 O 4 in original state (a), just damaged (b) and healed at 80 C for 10h (c).