Supporting Information Graphene-elastomer composites with segregated nanostructured network for liquid and strain sensing application Yong Lin, Xuchu Dong, Shuqi Liu, Song Chen, Yong Wei, Lan Liu* College of Materials Science and Engineering, Key Lab of Guangdong Province for High Property and Functional Macromolecular Materials, South China University of Technology, Guangzhou 510640, P. R. China * Corresponding author. E-mail: psliulan@scut.edu.cn Tel: +86 20-87114857. S-1
Figure S1. SEM images of segregated S-NRGE-0.42 composites (a and b) and homogeneous H-NRGE-0.42 composites (c and d). Figure S2. Comparison of mechanical properties of S-NRGE and H-NRGE as a function of GE content. (a) Tensile strength, (b) Elongation at break. S-2
Figure S3. Photographs of illumination changes for segregated S-NRGE-0.63 composites during immersing-drying process. Figure S4. Schematic of microstructural development for the segregated S-NRGE composites during the immersing-drying process. S-3
Table S1 The experimental formula for preparation of NR composites. Samples Neat GE-0.21 GE-0.42 GE-0.63 GE-0.84 GE-1.66 GE-3.27 GE 0 α 0.25 0.5 1.0 2.0 4.0 NRL 83.4 83.4 83.4 83.4 83.4 83.4 83.4 ZnO 2.5 2.5 2.5 2.5 2.5 2.5 2.5 SA 1 1 1 1 1 1 1 MB 0.5 0.5 0.5 0.5 0.5 0.5 0.5 CZ DM 0.25 0.25 0.25 0.25 0.25 0.25 0.25 S OP-10 α parts per fifty parts of solid rubber. S-4
Table S2 The comparison of electrical percolation threshold (φ c ) and conductivity for elastomer-ge composites previously reported. Samples φ c Conductivity (S m -1 ) Ref. TPU a /GE 0.05 vol% ~10-11 1 ENR b /GE 0.23 vol% ~10-10 2 SBR/GE 0.39 vol% ~10-9 3 NR/GE 0.21 vol% ~10-8 4 SBR/GE 0.55 vol% ~10-8 5 SBR/GE 1.76 vol% ~10-7 6 NR/GE 0.62 vol% ~10-7 7 S-NRGE 0.40 vol% ~10-6 a TPU: Thermoplastic polyurethane; b ENR: Epoxidized natural rubber. S-5
Table S3 Comparison of liquid sensing performance of polymer composites previously reported. Samples Responsivity Response time (s) Ref. TPU a /CB b 0~70 ~200 8 TPU/PP c /CB 0~4 120 9 PLA d /MWNT e 0~2 120~600 10 PC f /CNT g 0~2000 0~12000 11 PLA/MWNT 0~12 30~600 12 NR/MWNT/RGO h 1- ~250 13 NR/RGO@CNC i ~20000 180~500 14 NR/CB/CNs j 40~38000 85~560 15 H-NRGE-1.67 -- -- S-NRGE-0.42 234 56 S-NRGE-0.63 6700 114 S-NRGE-0.84 56700 350 a TPU: Thermoplastic polyurethane, b CB: Carbon black, c PP: Polypropylene, d Poly(Ɛ-caprolactone), e MWNT: Multiwalled carbon nanotubes, f PC: Polycarbonate, g CNT: Carbon nanotubes, h RGO: Reduced grapheme oxide, i CNs: Cellulose nanowhiskers. S-6
Table S4 Interaction parameters χ and characteristics of solvents and NR used in the present work. Substances Solubility parameter ((J/cm 3 ) 1/2, 25 C) Molar volume (cm 3 /mol, 25 C) Boiling point ( C) χ NR 16.7 - - - Xylene 18.0 123.3 144.4 0.088 Toluene 18.2 106.2 110.6 0.100 Petroleum ether 15.1 12 60~90 0.121 n-hexane 14.9 124.3 69 0.157 Tetrahydrofuran 18.8 80.9 65.4 0.148 Dichloromethane 19.9 64.0 39.8 0.269 S-7
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