advances.sciencemag.org/cgi/content/full/6/17/eaaz4191/DC1

Supplementary Materials for

Graphene reinforced carbon fibers

Zan Gao, Jiadeng Zhu, Siavash Rajabpour, Kaushik Joshi, Małgorzata Kowalik, Brendan Croom, Yosyp Schwab,

Liwen Zhang, Clifton Bumgardner, Kenneth R. Brown, Diana Burden, James William Klett, Adri C. T. van Duin*, Leonid V. Zhigilei*, Xiaodong Li*

*Corresponding author. Email: acv13@psu.edu (A.C.T.v.D.); lz2n@virginia.edu (L.V.Z.); xl3p@virginia.edu (X.L.)

Published 24 April 2020, Sci. Adv. 6, eaaz4191 (2020)

DOI: 10.1126/sciadv.aaz4191

This PDF file includes:

Figs. S1 to S10 Table S1

Fig. S1. Photo images (A) and viscosity (B) of different PAN/graphene spinning dopes (Photo Credit:

Zan Gao, University of Virginia). (C) Amplified area of (B).

Fig. S2. TEM images of (A) pure PAN precursor fiber and (B) PAN/graphene-0.075 composite fiber

along the fiber axis. (C) XRD patterns of the precursor PAN, oxidized PAN, and carbonized PAN fibers.

(D) XRD patterns of the PAN/graphene composite fibers with different graphene concentrations.

Fig. S3. TGA tests of pure PAN and PAN/graphene-0.075 composite fibers in different atmospheres.

(A) TGA curve of the pure PAN and PAN/graphene-0.075 fibers, which were heated to 250 ℃ at a

heating rate of 5 ℃/min in air. (B) TGA curves of the pure PAN and PAN/graphene-0.075 composite

fibers held at the temperature of 250 ℃ for 2 h in air. (C) Programmed heating profile of the TGA test:

the temperature was first ramped up to 250 °C at a heating rate of 5 °C/min in air, and then kept at this

temperature for 2 h, finally the samples were heated up to 1000 °C at a heating rate of 5 °C/min under N2

gas protection. (D) TGA curves of the oxidized PAN and PAN/graphene-0.075 under N2 protection.

Fig. S4. Microstructure and mechanical properties of PAN/graphene precursor fibers. SEM images

of the PAN/graphene precursor fibers with different weight percentages of graphene, (A) 0.00 wt.%, (B)

0.01 wt.%, (C) 0.025 wt.%, (D) 0.05 wt.%, (E) 0.075 wt.% and (F) 0.1 wt.%, insert is the amplified area

of (F). Comparison of strength (G), Young’s modulus (H), and strain (I) of the as-spun PAN/graphene

fibers with different concentrations of graphene.

Fig. S5. Microstructure and mechanical properties of the oxidized PAN/graphene fibers. SEM

images of the oxidized PAN/graphene precursor fibers with different weight percentages of graphene, (A)

0.00 wt.%, (B) 0.01 wt.%, (C) 0.025 wt.%, (D) 0.05 wt.%, (E) 0.075 wt.% and (F) 0.1 wt.%. Comparison

of strength (G), Young’s modulus (H) and strain (I) of the oxidized PAN/graphene fibers with different

concentrations of graphene.

Fig. S6. Comparison of (A) strength, (B) Young’s modulus, and (C) strain of PAN and PAN/graphene-

0.075 fibers after each processing step.

Fig. S7. Production of (A) CO and (B) CO2 molecules through ReaxFF.

Fig. S8. Alignment comparison of the oxidized PAN and oxidized PAN/graphene precursor fibers

based on Herman’s orientation function.

Fig. S9. Construction of ReaxFF and MD simulation box. (A) Construction of the ReaxFF

simulation box. The oxidized PAN chain (a) and single layer graphene sheet (b) used for the simulation

system. (c) The simulation box with graphene inclusion into 32 chains of oxidized PAN matrix after

equilibration for 60 ps. (B) The construction of the MD simulation box. (a) PAN chain and infinitely long

graphene sheet used in constructing initial configuration. Graphene sheet is 41.9 nm long in x-direction,

4.8 nm long in y-direction and contains 8000 atoms. (b) Initial configuration of the PAN/graphene

structure (HOF = -0.052). The graphene sheet is placed in the xy-plane near z = 20 nm. The carbon,

nitrogen, and hydrogen atoms are shown by green, blue, and white spheres, respectively. Carbon atoms

that belong to graphene sheet are shown by bigger spheres. (c) Orientation distribution of ring normal that

belongs to PAN chains with respect to x- and z-axes.

Fig. S10. AFM images of the shear-exfoliated graphene nanosheets.

Table S1. Processing parameters of the wet-spinning of PAN/graphene composite fibers.

PAN/graphene composite fibers

Solid content concentration: 7.5 g/100 ml ((PAN + graphene)/DMSO)

Spinning flow rate: (5 μL/min)

Spool diameter (5

cm) Roller 1 Roller 2 Roller 3

Speed (rpm) 25 35 45

Total draw ratio (fiber

diameter/nozzle

diameter)

10