Phenolic foam-derived magnetic carbon foams (MCFs) with tunable electromagnetic wave absorption behavior

Journal Pre-proofs Phenolic Foam-Derived Magnetic Carbon Foams (MCFs) with Tunable Electromagnetic Wave Absorption Behavior Zhichao Lou, Ru Li, Peng Wang, Yao Zhang, Bo Chen, Caoxing Huang, Chaochao Wang, He Han, Yanjun Li PII: DOI: Reference:

S1385-8947(19)32986-9 https://doi.org/10.1016/j.cej.2019.123571 CEJ 123571

To appear in:

Chemical Engineering Journal

Received Date: Revised Date: Accepted Date:

16 August 2019 17 November 2019 19 November 2019

Please cite this article as: Z. Lou, R. Li, P. Wang, Y. Zhang, B. Chen, C. Huang, C. Wang, H. Han, Y. Li, Phenolic Foam-Derived Magnetic Carbon Foams (MCFs) with Tunable Electromagnetic Wave Absorption Behavior, Chemical Engineering Journal (2019), doi: https://doi.org/10.1016/j.cej.2019.123571

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© 2019 Published by Elsevier B.V.

Phenolic Foam-Derived Ultralight Porous Magnetic Carbon Foams (MCFs) with Tunable Electromagnetic Wave Absorption Behavior by Modulating Composition and Skeleton Microstructure Zhichao Lou1,2, Ru Li1, Peng Wang3, Yao Zhang1, Bo Chen4, Caoxing Huang5, Chaochao Wang1, He Han1,6, Yanjun Li1,* 1. College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China. 2. Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing 210037, China 3. State Key Laboratory of Pharmaceutical Biotechnology, Department of Sports Medicine and Adult Reconstructive Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China 4. Materials Science and Devices Institute, Suzhou University of Science and Technology, Suzhou 215009, China 5. College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China 6. Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China *Corresponding Author: [email protected]

Figure S1. (A-C) Diagram of solid and translucent reaction vessels. (C) Weights and the lids for placing the weights. (D) Schematic diagram of foaming reaction under control of external pressure.

Table S1. The naming of the samples. Concentration of Fe(acac)3

Pressure

DMF solution (g/mL)

(MPa)

Foam-0

0

0.4

No

Foam-1

0.04

0.4

No

Foam-2

0.08

0.4

No

Foam-3

0.12

0.4

No

CF

0

0.4

Yes

MCF-1

0.04

0.4

Yes

MCF-2

0.08

0.4

Yes

MCF-3

0.12

0.4

Yes

MCF-4

0.12

0.2

Yes

MCF-5

0.12

0.6

Yes

Name

Carbonization

Figure S2. The schematic diagram (A) and physical photograph (B) of the mold for the sample preparation. (C) The practicality photograph of the toroidal-shaped (Φout: 7.0 mm, Φin: 3.04 mm) testing sample. (D) The diagram of the experimental components of the network analyzer.

Figure S3. (A) SEM images of the cross-section of CF. The graphite-like sheets are pointed by yellow arrows. (B) EDS mapping images of C, Fe and C elements in CF.

Figure S4. (A) SEM images of the cross-section of MCF-1. The graphite-like sheets are pointed by yellow arrows. (B) EDS mapping images of C, Fe and C elements in MCF-1.

Figure S5. (A) SEM images of the cross-section of MCF-2. The graphite-like sheets are pointed by yellow arrows. (B) EDS mapping images of C, Fe and C elements in MCF-2.

Figure S6. The representative images of the obtained samples, along with the corresponding micro-CT cross-section and 3D reconstruction images.

Table S2. The percentages of the functional groups of the samples. C 1s (atom %) C=C

C-C

C-O

Fe3C

Foam-0

19.2

58.0

22.8

0

CF

64.8

35.2

0

0

MCF-1

38.1

38.8

0

23.1

MCF-2

31.9

26.6

0

41.5

MCF-3

27.8

24.1

0

48.1

Figure S7. (A) The reaction pathway of phenolic resin during the pyrolysis processes. (B) The reaction pathway of Fe(acac)3 during the pyrolysis processes.

Figure S8. VSM curves of CF, MCF-1, MCF-2, MCF-3, MCF-4 and MCF-5.

Figure S9. Force-distance curves of the compressive strength testing of the samples. Insert: physical image of the testing process for MCF-3 as a sample.

Table S3. Results of the compressive strength test. Samples

Foam-0

CF

MCF-1

MCF-2

MCF-3

0.15±0.02

0.05±0.01

0.08±0.02

0.21±0.04

0.35±0.02

Compressive strength (MPa)

Figure S10. (A-C) Dielectric parameters (real permittivity, imaginary permittivity and dielectric loss) of CF, respectively. (D-F) Magnetic parameters (real permeability, imaginary permeability and magnetic loss) of CF, respectively.

Figure S11. Frequency dependence of RL values of CF.

Figure S12. Frequency dependence of RL values at various thickness ranges: (A) 3.75-5.00 mm, (B) 2.25-3.20 mm, and (C) 1.65-2.20 mm.

Figure S13. (A) Frequency dependence of microwave transmitting in MCF-3. Inset shows the photograph of thickness for MCF-3/paraffin composites using Vernier caliper. (B) Reflection loss value of MCF-3 at 3.47 mm. (C) C0 curves of MCF-1 (black), MCF-2 (red) and MCF-3 (blue). (D) The attenuation constant values (a) of MCF-1 (black), MCF-2 (red) and MCF-3 (blue). (E) Curves of Zin/Z0 vs frequency for MCF-1 (black), MCF-2 (red) and MCF-3 (blue).

Figure S14. The five-point BET surface area analysis for MCF-3, MCF-4 and MCF-5.

Table S4. The summarized absorption properties for the obtained carbon-based absorbers. Matching

Matching

frequency (GHz)

thickness (mm)

-15.37

5.72

4.50

MCF-1

-41.33

13.64

2.15

MCF-2

-53.74

13.16

4.00

MCF-3

-54.02

8.92

3.05

MCF-4

-43.97

8.68

2.70

MCF-5

-41.33

13.64

2.15

Absorbers

RLmin (dB)

CF

Figure S15. (A-C) Dielectric parameters (real permittivity, imaginary permittivity and dielectric loss) of MCF-3, MCF-4 and MCF-5. (D-F) Magnetic parameters (real permeability, imaginary permeability and magnetic loss) of MCF-3, MCF-4 and MCF-5.

Four-point probe characterization Four-point probe meter (KDY-1) of K.D. Technology Co., Ltd. in Guangzhou. MCF-3, MCF-4 and MCF-5 are pressed into disc-shape with diameter of 8 mm and thickness of 1~2 mm. The resistances of the samples are calculated according to the following equation (1): 𝑅0 = 𝑉/𝐼 ∙ 𝐹𝑆𝑃 ∙ 𝐹(𝑊/𝑆) ∙ 𝐹(𝑆/𝐷) ∙ 𝐹𝑟 (1) where W corresponds to the thickness of the sample, F(W/S) is the thickness correction coefficient, F(S/D) is the diameter correction coefficient, 𝐹𝑆𝑃 represents probe spacing correction coefficient which is normally 4.532. The conductivities (σ) for the three MCFs are calculated according to the following equation (2): σ = W/𝑅0 (2) The skin depth (δ) values are obtained according to the following equation (3) as below: δ=

1 𝜋𝑓𝜇0𝜇𝑖𝜎

(3)

where f is the frequency, μ is the permeability of vacuum which is normally 4Πx10-7, and μi is the relative permeability. 

Magnetic porous graphitic carbon-based foams are synthesized



Ultralight EMW absorbers with strong capacity, broad frequency and thin thickness



The mechanism of the EMW absorption behavior has been discussed in depth.



Effect of internal cell-wall thickness on EMW absorption behavior is investigated



Effective adsorption from C to Ku band is achieved via adjusting absorber thickness

Declaration of interests ☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

☐The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: