Supplementary Information Highly Strong and Elastic Graphene Fibres Prepared from Universal Graphene Oxide Precursors Guoji Huang, 1 Chengyi Hou, 1 Yuanlong Shao, 1 Hongzhi Wang, *,1 Qinghong Zhang, 1 Yaogang Li *, 2 and Meifang Zhu 1 1 State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, 201620 (People s Republic of China) 2 Engineering Research Center of Advanced Glasses Manufacturing Technology, College of Materials Science and Engineering, Donghua University, 201620 (People s Republic of China) 1
Supplementary Figure S1. a) Atomic force microscopy (AFM) images of GO sheets. b) The photograph of GO hydrogel. 2
To prove the high quality of the GO hydrogel, a FTIR spectrum is shown in Fig. S2 I. The OH stretching vibration is observed at 3418 cm 1 in the pristine NaDC spectrum (a), which slightly shifted to 3425 cm 1 when it was adsorbed on GO. The absorptions for the C H bending vibration also shifted from 2937 and 2864 cm 1 of pristine NaDC to 2936 and 2865 cm 1 of GO-triggered NaDC. The COOH stretching vibration are observed around 1558 and 1406 cm 1 of pristine NaDC, which shifted to a lower frequency region at 1560 and 1401 cm 1 of GO-triggered NaDC (b). This result indicates that NaDC molecules were well dispersed in the GO aqueous solution. After the NaDC molecules were completely dissolved by water ethanol solvent exchange, we can clearly observe the FTIR spectra for GOFs. In the GOFs spectrum (c), the peak at 3,428 cm -1 can be attributed to OH stretching vibration. The band at 2936 and 2865cm -1 is greatly lowered in intensity, furthermore, the band at 1560 cm -1 disappeared which indicates that NaDC molecules were well dissolved by the solvent exchange process. The C=O group absorption around 1725 cm -1 for the COOH groups at the edges of the sheets is lowered in intensity. The structural OH and epoxide groups are observed at 1629 cm -1 and the band at 1400 cm -1 can be ascribed to the OH deformation vibration of COOH groups. After chemical reduction the GOFs (d), the structural OH and epoxide groups absorption at 1629 cm -1 disappeared and new absorption band at 1577 cm -1 in GFs spectrum can be attributed to the skeletal vibrations in the graphene sheets, which are consistent with the reduction of GOFs 24-26. 3
Supplementary Figure S2. I) The FTIR spectra of the pristine NaDC (a), GO hydrogel with Ø GO =30%,Ø NaDC =8% (b), the GOFs after by ethanol solvent-exchange (c), reduced GFs (d), II and III) Raman spectra and XRD patterns of the GOFs, GFs, GRs, and EGRs. Further Raman spectra and XRD analysis were taken to study the structure of GOFs, GFs, GRs and the as-prepared EGRs samples. The Raman spectra in Fig. S2 II show the characteristic D- and G-bands of those samples respectively. The D-band is quite intense in the GFs, GRs and EGRs samples and the intensity ratios for the D and G bands (I D /I G ) change from 0.94 (GOFs) to 1.17 (GFs), 1.13 (GRs) and 1.26 (EGRs), respectively, these results suggested the decrease in the average size for the sp 2 domains upon the reduction of GOFs and a deeper reduction in EGRs in comparison to GFs and GRs. The X-ray diffraction studies (Fig. S2 III) further indicate that the sharp peak centered at 2θ=10.48 for GOFs and broad peak centered at 2θ=24.42 for GFs, 2θ=23.48 for GRs and 2θ=23.1 for EGRs, respectively, which are corresponding to the interlayer spacing of the ordered GO and GR, the interlayer spacing decreases due to the elimination of pendant functional groups of GO sheets by the chemical reduction 1, 25-27. 4
Supplementary Figure S3. FE-SEM images for the GFs was knotted into a loop. Scale bars: 500µm. 5
Supplementary Table S1. Comparison of the electrical conductivity, failure strain and tensile strength of our work and other GFs. Sample Conductivity (S/m) Strain (%) Tensile strength (MPa) Ref. GFs 3.08 10 4 2.0 238 Our work GRs 6.3 10 4 2.3 404 Our work EGRs 3.55 10 4 85.0 102 Our work Graphene Fibres 2.5 10 4 5.8 140 [9] Graphene Fibers 1.0 10 3 4.2 180 [10] Graphene Fibers 3.5 10 3 3.1 182 [11] Graphene 1.0 10 3 4.0 180 [16] Microtubings Giant Graphene 4.1 10 4 6.7 501 [17] Fibres Ag-Doped Giant 9.3 10 4 5.5 305 [18] Graphene Fibres Annealed Graphene 2.85 10 4 1.0 378 [19] Nanoribbons Graphene Ribbons 1.0 1.5 10 4 14.0 40 [37] Supplementary Methods FTIR spectra were recorded on a Nicolet NEXUS-670 spectrometer with KBr pellets in the 4000 500 cm -1 region. Raman spectra were recorded on a Renishaw in plus laser Raman spectrometer with λ exc =432 nm. XRD spectroscopy was carried out on a Rigaku D/max 2550 V X-ray diffractometer using Cu Ka irradiation (λ= 1.5406 Å) at 40 kv and 300 ma. AFM images of GO sheets were taken out using a Nanoscope IV SPM (Digital Instruments) at a scan rate of 1 Hz. Supplementary Movie S1. The spinning process of GOFs. Supplementary Movie S2. The stretching process of the EGR. 6