Supplementary Information
Mimicking how Plants Control CO2 Influx: CO2 Activation of
Ion Current Rectification in Nanochannels
Yanglei Xu‡, Minghui Zhang‡, Tong Tian, Ying Shang, Zheyi Meng, Jiaqiao Jiang, Jin Zhai*,
Yao Wang*
Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, Key
Laboratory of Beijing Energy, School of Chemistry and Environment, Beihang University, Beijing 100191, P. R.
China.
*zhaijin@buaa.edu.cn; yao@buaa.edu.cn
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Supplementary Figures
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CH3OH e
H2O
Figure S1. Synthesis strategy of DEDA. 1H NMR (δ, ppm, CDCl3): 12.490 (s, -COOH),
3.345-3.384 (t, COOH-CH2-), 3.285 (s, -N-N(CH3)2), 2.219-2.251 (t, =N-CH2-), 2.171 (s,
-N=CCH3), 1.282-1.336 (d, -(CH2)9-).
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Figure S2. Synthesis strategy of DEPBA. 1H NMR (ppm, 400 MHz, DMSO-d6) δ7.02-6.96
(m, 2H), 6.52-6.46 (m, 2H), 2.94-2.90 (s, 6H), 2.54-2.48 (m, 2H), 2.16-2.10 (m, 2H),
1.80-1.78 (s, 3H), 1.78-1.70 (m, 2H).
Figure S3. The infrared spectrum of PET before and after DPBDA or DEDA modification.
Figure S4. The corresponding XPS spectra of PET films before and after DEPBA
modification.
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Figure S5. The corresponding XPS spectra of PET films before and after DEDA
modification.
Figure S6. Ionic transport properties of the nanochannel before and after DEDA modification
were examined by current measurements. The corresponding I-V curves of modification
progress on pH=4 (HCl).
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Figure S7. I-V curves of CO2 and N2 bubbling in DEDA -modified nanochannels.
Figure S8. The current-voltage (I-V) curves of the nanochannel with amine groups when
bubbling with CO2 and pH to 4.0 solution.
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Figure S9. Ion rectification ratio of CO2 responsive nanochannels modified with DEPBA and
EDA.
Figure S10. The current-voltage (I-V) curves of the nanochannels with amidine groups when
bubbling with CO2 or adding HCO3- solution.
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Figure S11. I-V properties of gas responsive functionalized nanochannels (a) before and (b)
after DEDA modification when bubbling CO2 for different time. (c) The CO2 activated gating
ratio of nanochannels at -2.0 V voltage before and after phenylamidine modification. (d) Ion
rectification ratio of gas responsive nanochannels before and after modification.
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Figure S12. SEM image of the base of the nanochannels. The diameter was ~300 nm. The
diameter of the base was estimated by environmental scanning electronic microscope. The
SEM image of the base side was obtained by a Hitachi S-4300 microscope at an accelerating
voltage of 5 kV.
Figure S13. The Poisson and Nernst-Planck (PNP) model.
Figure S14. Schematic illustrations of modification progress. The surface functional
groups changed from -COOH groups (step 1) to -NH2 groups (step 2), and then modified by
DEPBA or DEDA (step 3), R = C(CH2)(CH2)3C6H6, (DEPBA) or COCH2, (DEDA).
Supplementary Note
The diameter of the small opening which was called tip (dtip) was estimated by the
following relation:
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Where L is the length of the channel, I and U is the measured current and the applied
voltage, respectively, dtip is the tip diameter, D is the base diameter, k(c) is the special
conductivity of the electrolyte. For 1 M KCl solution at 25 oC, k(c) is 0.11173 Ω-1cm-1. In this
work, the base diameter was ~300 nm, and the tip diameter was ~10 nm.
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