Supporting Information for

Mussel-inspired, Self-healing Polymer Blends

Shengju Song,†, ‡, # Haoyu Yang,†, # Yijie Cui,† Yifeng Tang,† Yanzheng Chen,† Biao Yang,§ Jikang

Yuan,%,* Jijun Huang†,*

†College of Materials Science and Opto-Electronic Technology and Center of Materials Science and

Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China

‡R. & D. Department, China Academy of Launch Vehicle Technology, Beijing 100076, P. R. China

§School of Materials Science and Mechanical Engineering, Beijing Technology and Business

University, Beijing 100048, P. R. China

%School of Materials Science and Energy Engineering, Foshan University, Foshan, Guangdong

528225, P. R. China

*Corresponding authors: jiyuan929@163.com (J. K.Y) and jjh06@mit.edu (J. J. H)

#S.J.S and H.Y.Y contributed equally to the work.

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1H NMR Analysis of DMA, PDMA, and PDMA/PU Blends. DMA was confirmed by 1H NMR

with deuterated dimethyl sulfoxide (d6-DMSO) as a good solvent: 1H NMR (400 MHz, DMSO, 273

K), 6.4–6.6(3H, m, Ph), 5.5 (1H, d, CH2=C–), 5.25 (1H, d, CH2=C–), 3.3 (2H, q, CH2–NH–), 2.5 (2H,

tr, CH2–Ph), 1.8 (3H, s, CH3–C–). The structure of PDMA was also confirmed by 1H NMR (Fig. S1)

with deuterated dimethyl sulfoxide (d6-DMSO) as a good solvent.

Comparison of 1H NMR spectra was made between DMA, PDMA, PDMA/PU (10/90),

PDMA/PU(20/80), and PU, as shown in Fig. S2. Clearly, the blend contains the DMA units,

confirming the effectiveness of our strategy for forming novel, mussel-inspired, multi-phased materials.

Fig. S1. 1H NMR spectra of neat PDMA.

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Fig. S2. Comparison of 1H NMR spectra between DMA, neat PDMA, PDMA/PU (10/90), PDMA/PU(20/80), and PU.

Mass Spectroscopy Analysis of PDMA and PDMA/PU Blends. MALDI-TOF mass spectrometry

was performed on a Bruker Autoreflex III equipped with a 355 nm N2 laser in the reflector mode and

20 kV acceleration voltage. Dithranol (Aldrich, 97%) was used as the matrix. Sodium or potassium

trifluoroacetate was added for ion formation. Samples were prepared from CH3OH solution by mixing

matrix (~20 mg/mL), sample (~10 mg/mL) and salt (~10 mg/mL) in a ratio of 10:1:1. The weight

average molecular weight of neat PDMA was seen to be around 1650 g/mol with or without prior

purification (Fig. S3); the same value emerged for the molecular weight of PDMA in PDMA/PU but

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this blend showed a much broader molecular weights distribution largely as a result of the chain

transfer effect during free radical polymerization.

Fig. S3. Comparison of mass spectra revealed by MALDI-TOF-MS between neat PDMA and PDMA/PU(10/90). PDMA was measured with and without prior purification.

Differential Scanning Calorimetry Analysis (DSC) of PDMA/PU Blends. Thermal analysis of the

formed blends was performed with a differential scanning calorimeter (DSC Q100, TA Instruments

Inc.) under nitrogen atmosphere. The samples of 3 －5 mg were heated to 100 °C (or 150 °C) at 10

°C/min and maintained for 3 min to erase the prior thermal history. Subsequently, the samples were

cooled to ―100 °C at a rate of 10 °C/min. Then, the samples were re-heated to 200 °C at a rate of 10

°C/min. The data in second heat were used for analysis.

Dynamic Mechanical Analysis of PDMA/PU Blends. The dynamic mechanical properties of

PDMA/PU blends were evaluated using a TA dynamic mechanical analyzer Q800 under tension mode.

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Rectangular-shaped specimens were cut from the strips and had a size of 30×6.0×0.60 mm3 for

testing. The dynamic testing was conducted from ―100 to +100 °C at a heating rate 3 °C/min under 1

Hz and a strain of 0.1%. Storage and loss moduli as well as loss tangent were recorded as a function of

temperature.

Fig. S4. TEM photomicrographs showing phase separation for: (a) PDMA/PU(5/95) (b)

PDMA/PU(15/85), (c) PDMA/PU(20/80), and (d) PDMA/PU(30/70).

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Fig. S5. Phase-separated morphology for: (a) PDMA/PU(10/90) revealed by AFM imaging, and (b)

PDMA/PU(20/80) revealed by SEM imaging.

Fig. S6. DSC analysis of PDMA/PU blends and Tg of PU soft segments as a function of the PDMA

content deduced from DSC curves.

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Fig. S7. Dynamic mechanical analysis of neat PDMA: (a) storage and loss moduli as a function of

temperature, and (b) Tan delta as a function of temperature.

Fig. S8. Tensile strength of PDMA/PU blends as a function of the PDMA concentration.

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Fig. S9. Tensile stress vs. strain curves for PDMA/PU blends before and after healing: (a) PDMA/PU

(2/98), (b) PDMA/PU(5/95), (c) PDMA/PU(15/85), (d) PDMA/PU(20/80), and (e) PDMA/PU(30/70).

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