Supporting Information

Mechanically strong and thermally insulating polyimide aerogels by

homogeneity reinforcement of electrospun nanofibers

Xingyu Zhao a, Fan Yang a, Zicheng Wang b, Piming Ma b, Weifu Dong b, Haoqing

Hou c, Wei Fan a,*, and Tianxi Liu a,b,*

a State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,

College of Materials Science and Engineering, Innovation Center for Textile Science

and Technology, Donghua University, 2999 North Renmin Road, Shanghai 201620,

China.

b Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School

of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China.

c Department of Chemistry and Chemical Engineering, Jiangxi Normal University,

Nanchang 330022, China.

* Corresponding Author.

E-mail: txliu@dhu.edu.cn or txliu@fudan.edu.cn (T. X. Liu), weifan@dhu.edu.cn (W.

Fan)

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Experimental details

Characterization

The morphologies of the short polyimide nanofibers and aerogels were observed by

scanning electron microscope (SEM, HitachiS-8010, Japan). Thermogravimetric

analysis (TGA) was performed on a NETZSCH TG 209 F1 Libra under air with a

heating rate of 10 °C/min from 100 to 800 °C. The mechanical property test was

performed on a universal testing machine (SANS UTM2102, China) equipped with a

100 N sensor at a compression rate of 40 mm min -1. Thermographic images were

taken by an infrared thermal camera (TiS40, Fluke Co., Ltd, USA). The thermal

conductivity was measured by a Hot Disk Thermal Constants Analyzer (Hot Disk TPS

2500S, Sweden) with a Kapton sensor (Hot Disk 5465). The applied measurement

time and heating power were 10 s and 10 mW, respectively.

Figure captions

Fig. S1. SEM images of short polyimide nanofibers (A) before and (B) after

dispersion.

Fig. S2. SEM images of (A) NRPI-5 and (B) NRPI-20.

Fig. S3. Stress-strain curve of NRPI-10 aerogel with a high strain (90%). Inset shows

the digital photos of NRPI-10 before and after compression.

Fig. S4. SEM image of NRPI-20 with clear nanofiber agglomeration.

Fig. S5. Stress-strain curve of NRPI aerogels with different short polyimide nanofiber

lengths.

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Fig. S6. The relative modulus (defined as the measured Young’s modulus E divided

by the Young’s modulus of the constituent solid Es) of NRPI aerogels with or without

polyimide nanofibers.

Fig. S7. Compressive cycles of NRPI-10 aerogels at the strain of 25% for 100 cycles.

Fig. S8. Finite element method (FEM) model of NRPI-0.

Fig. S9. Finite element method (FEM) model of NRPI-10.

Fig S10. Thermal conductivity of NRPI-0 and NRPI-10 aerogels in axial and radial

directions.

Fig. S11. TGA curve of NRPI-10 under air atmosphere.

Fig. S1. SEM images of short polyimide nanofibers (A) before and (B) after

dispersion.

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Fig. S2. SEM images of (A) NRPI-5 and (B) NRPI-20.

Fig. S3. Stress-strain curve of NRPI-10 aerogel with a high strain (90%). Inset shows

the digital photos of NRPI-10 before and after compression.

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Fig. S4. SEM image of NRPI-20 with clear nanofiber agglomeration.

Fig. S5. Stress-strain curve of NRPI aerogels with different short polyimide nanofiber

lengths.

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Fig. S6. The relative modulus (defined as the measured Young’s modulus E divided

by the Young’s modulus of the constituent solid Es) of NRPI aerogels with or without

polyimide nanofibers.

Fig. S7. Compressive cycles of NRPI-10 aerogels at the strain of 25% for 100 cycles.

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Fig. S8. Finite element method (FEM) model of NRPI-0.

Fig. S9. Finite element method (FEM) model of NRPI-10.

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Fig S10. Thermal conductivity of NRPI-0 and NRPI-10 aerogels in axial and radial

directions.

Fig. S11. TGA curve of NRPI-10 under air atmosphere.

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