Nano Res.

Electronic Supplementary Material

Self-healing superhydrophobic polyvinylidene fluoride/Fe3O4@polypyrrole fiber with core–sheath structures for superior microwave absorption

Yunan Li1, Yong Zhao1, Xianyong Lu1 (), Ying Zhu1 (), and Lei Jiang1,2

1 Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment,

Beihang University, Beijing 100191,China 2 Laboratory of Bio-inspired Smart Interfacial Science, Technology Institute of Physics and Chemistry, Chinese Academy of Science, Beijing

100190, China

Supporting information to DOI 10.1007/s12274-016-1094-x

TEM image of PVP-coated Fe3O4 nanoparticles is shown in Fig. S1(a). It can be observed that magnetite

nanoparticles exhibit spherical shape without obvious agglomeration. The histogram based on statistical results

(Fig. S1(b)) shows that the average size of Fe3O4 nanoparticles is 8.5 ± 1.5 nm. The XRD pattern (Fig. S1(c)) exhibits

prominent peaks at 2θ = 30.1°, 35.5°, 43.1°, 53.6°, 57.1°, 62.7°, 71.2° and 74.3° corresponding to (220), (311), (400),

(420), (511), (440), (620) and (533) reflections of the magnetite (JCPDS no. 19-0629), respectively. In Fig. S1(d),

the broad band in the range of 3,700 to 3,000 cm–1 is attributed to O–H stretching vibration for polyol molecules

absorbed to the nanoparticles surface [S1]. In addition, the sharp peak at about 578 cm–1 is ascribed to Fe–O

stretching vibration of Fe3O4 nanoparticles [S2]. The peaks at around 2,931–2,850, 1,460 and 1,072 cm–1 are due

to C–H stretching vibration, C–H bending vibration and C–O stretching vibration, respectively [S2]. The

characteristic peak at 1,664 cm–1 is assigned to C=O stretching vibration, suggesting that PVP was modified on

the surface of Fe3O4 nanoparticles via coordination interaction through its carbonyl group [S1]. According to

the TG curve (Fig. S1(e)), the percentage of PVP modified on the surfaces of Fe3O4 nanoparticles is 29.0 wt.%.

Magnetization curve (Fig. S1(f)) of Fe3O4 nanoparticles measured at room temperature shows that the as-

prepared Fe3O4 nanoparticles were superparamagnetic with saturation magnetization (Ms) of 56.5 emu/g. Fe3O4

nanoparticles exhibit good colloidal stability in ethanol, even though the dispersion is exposed to an external

magnetic field (inset in Fig. S1(f)).

Address correspondence to Xianyong Lu, xylu@buaa.edu.cn; Ying Zhu, zhuying@buaa.edu.cn

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Figure S1 (a) TEM image; (b) statistical histogram; (c) XRD pattern and (d) FT-IR spectrum; (e) TG curve; (f) magnetization curve of Fe3O4 nanoparticles (inset: digital photograph the ethanol dispersion of Fe3O4 nanoparticles in absence or presence of magnetic field).

Figure S2 Digital photographs of free-standing and flexible PVDF/Fe3O4@PPy0.075 film.

It can be observed from Fig. S3 that more nanoparticles are formed on the surface of PVDF/Fe3O4@PPy0.10 film

as the feeding of pyrrole monomers increases from 0.05 g to 0.10 g in chemical oxidative polymerization.

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Figure S3 SEM images of PVDF/Fe3O4@PPy0.05 film ((a) and (b)), PVDF/Fe3O4@PPy0.075 film ((c) and (d)) and PVDF/Fe3O4@PPy0.10 film ((e) and (f)).

In Fig. S4(a), peak located at 1,190 cm–1 can be ascribed to C–F characteristic stretching vibration peak of

PVDF [S3], the peaks at 840 and 1,281 cm–1 are the characteristic bands of β-phase crystallites of PVDF [S3]. In

Fig. S4(b), there are no obvious characteristic absorption peaks of Fe3O4 nanoparticles due to high content of

PVDF in PVDF/Fe3O4 fiber film. In Fig. S4(c), the band at 1,561 cm–1 is related to the C=C double bond

stretching vibrations of pyrrole rings [S4]. The peak of =C–H in-plane vibration is found at 1,051 cm–1 [S5]. The

appearance of peak at 1,664 cm–1 is attributed to carbonyl group, which indicates that PPy is slightly

overoxidized during the polymerization process [S4]. The above-mentioned results confirm that PPy was

successfully coated in PVDF/Fe3O4 film by the chemical oxidative polymerization.

Figure S4 FT-IR spectra of PVDF, PVDF/Fe3O4 fiber film and PVDF/Fe3O4@PPy0.075 film.

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Figure S5 shows the TGA curves of the samples in our experiment. According to the TG curves, we calculated

the mass fraction of the component in each sample, and the corresponding results are illustrated in Table S1.

Figure S5 TGA curves of the samples.

Table S1 Mass fraction of the components in the samples

wt.% Samples

PVDF PVP-coated Fe3O4 PPy

PVDF/Fe3O4 76.2 23.8 0

PVDF/Fe3O4@PPy0.05 75.2 23.5 1.3

PVDF/Fe3O4@PPy0.075 73.7 23.0 3.3

PVDF/Fe3O4@PPy0.10 72.3 22.5 5.2

Figure S6 C0–f curves of PVDF/Fe3O4 fiber film and F-PVDF/Fe3O4@PPyx films.

Table S2 Microwave absorption performance of PVDF/Fe3O4, F-PVDF/Fe3O4/PPyx fims

Samples Max RL

value (dB) Corresponding

d (mm) Frequency range

(GHz) (RL < –10 dB) Bandwidth

(RL < –10 dB)

PVDF/Fe3O4 –4.4 2.5 — —

F-PVDF/Fe3O4@PPy0.05 –48.8 5.0 6.0–9.7 3.7

F-PVDF/Fe3O4@PPy0.075 –21.5 2.0 13.6–18.0 4.4

F-PVDF/Fe3O4@PPy0.10 –5.9 2.5 — —

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Figure S7 The photograph of sliding angle for F-PVDF/Fe3O4@PPy0.075 film.

References

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