In this work, experiments, molecular dynamics (MD) simulations, and theoretical analysis are conducted to study ion transport in thin carbon nanotubes (CNTs). Diverse nonlinear relationships between the ionic conductance (G) and the ion concentration (C) are observed. MD simulations show that the distinct GC dependences are caused by the functionalization of the CNT entrance, which affects the energy barrier for ion transport and changes the ionic conductance. The various GC relationships are also predicted using the electrokinetic theory by considering the potential generated by the functional groups at the CNT entrance. Practically, the number of functional groups at the CNT entrance is influenced by several factors, including both intrinsic and external effects, which make it difficult to regulate the ionic conductance and pose a challenge to CNT-based nanofluidic systems in practical applications.

1.
R. B.
Schoch
,
J.
Han
, and
P.
Renaud
, “
Transport phenomena in nanofluidics
,”
Rev. Mod. Phys.
80
,
839
(
2008
).
2.
Z.
Cheng
,
Z.
Ning
,
W.
Zhang
, and
S.
Ke
, “
Theoretical investigation of electroviscous flows in hydrophilic slit nanopores: Effects of ion concentration and pore size
,”
Phys. Fluids
32
,
022005
(
2020
).
3.
Z.
Li
,
Nanofluidics: An Introduction
(
CRC Press
,
2018
).
4.
E.
Amani
,
M.
Mehrabian
, and
S.
Movahed
, “
A discrete phase hybrid continuum-atomistic model for electrokinetics in nanofluidics
,”
Phys. Fluids
30
,
072003
(
2018
).
5.
X.
Gao
,
T.
Zhao
, and
Z.
Li
, “
Controlling flow direction in nanochannels by electric field strength
,”
Phys. Rev. E
92
,
023017
(
2015
).
6.
C.-C.
Chang
,
R.-J.
Yang
,
M.
Wang
,
J.-J.
Miau
, and
V.
Lebiga
, “
Liquid flow retardation in nanospaces due to electroviscosity: Electrical double layer overlap, hydrodynamic slippage, and ambient atmospheric CO2 dissolution
,”
Phys. Fluids
24
,
072001
(
2012
).
7.
Y.
Jin
,
R.
Tao
, and
Z.
Li
, “
Understanding flow enhancement in graphene-coated nanochannels
,”
Electrophoresis
40
,
859
(
2019
).
8.
S.
Luo
,
C.
Li
,
F.
Li
,
J.
Wang
, and
Z.
Li
, “
Ice crystallization in shear flows
,”
J. Phys. Chem. C
123
,
21042
(
2019
).
9.
S.
Ghosh
,
A.
Sood
, and
N.
Kumar
, “
Carbon nanotube flow sensors
,”
Science
299
,
1042
(
2003
).
10.
J.
Wu
,
K. S.
Paudel
,
C.
Strasinger
,
D.
Hammell
,
A. L.
Stinchcomb
, and
B. J.
Hinds
, “
Programmable transdermal drug delivery of nicotine using carbon nanotube membranes
,”
Proc. Natl. Acad. Sci. U. S. A.
107
,
11698
(
2010
).
11.
H. G.
Park
and
Y.
Jung
, “
Carbon nanofluidics of rapid water transport for energy applications
,”
Chem. Soc. Rev.
43
,
565
(
2014
).
12.
F.
Faraji
and
A.
Rajabpour
, “
Temperature gradient-induced fluid pumping inside a single-wall carbon nanotube: A non-equilibrium molecular dynamics study
,”
Phys. Fluids
28
,
092004
(
2016
).
13.
A.
Kalra
,
S.
Garde
, and
G.
Hummer
, “
Osmotic water transport through carbon nanotube membranes
,”
Proc. Natl. Acad. Sci. U. S. A.
100
,
10175
(
2003
).
14.
B.
Corry
, “
Water and ion transport through functionalised carbon nanotubes: Implications for desalination technology
,”
Energy Environ. Sci.
4
,
751
(
2011
).
15.
F.
Fornasiero
,
H. G.
Park
,
J. K.
Holt
,
M.
Stadermann
,
C. P.
Grigoropoulos
,
A.
Noy
, and
O.
Bakajin
, “
Ion exclusion by sub-2-nm carbon nanotube pores
,”
Proc. Natl. Acad. Sci. U. S. A.
105
,
17250
(
2008
).
16.
H.
Sui
,
B.-G.
Han
,
J. K.
Lee
,
P.
Walian
, and
B. K.
Jap
, “
Structural basis of water-specific transport through the AQP1 water channel
,”
Nature
414
,
872
(
2001
).
17.
T. I.
Brelidze
,
X.
Niu
, and
K. L.
Magleby
, “
A ring of eight conserved negatively charged amino acids doubles the conductance of BK channels and prevents inward rectification
,”
Proc. Natl. Acad. Sci. U. S. A.
100
,
9017
(
2003
).
18.
S.
Dalla Bernardina
,
E.
Paineau
,
J.-B.
Brubach
,
P.
Judeinstein
,
S.
Rouzière
,
P.
Launois
, and
P.
Roy
, “
Water in carbon nanotubes: The peculiar hydrogen bond network revealed by infrared spectroscopy
,”
J. Am. Chem. Soc.
138
,
10437
(
2016
).
19.
H.
Liu
,
J.
He
,
J.
Tang
,
H.
Liu
,
P.
Pang
,
D.
Cao
,
P.
Krstic
,
S.
Joseph
,
S.
Lindsay
, and
C.
Nuckolls
, “
Translocation of single-stranded DNA through single-walled carbon nanotubes
,”
Science
327
,
64
(
2010
).
20.
S.
Guo
,
S. F.
Buchsbaum
,
E. R.
Meshot
,
M. W.
Davenport
,
Z.
Siwy
, and
F.
Fornasiero
, “
Giant conductance and anomalous concentration dependence in sub-5 nm carbon nanotube nanochannels
,”
Biophys. J.
108
,
175a
(
2015
).
21.
E.
Secchi
,
A.
Niguès
,
L.
Jubin
,
A.
Siria
, and
L.
Bocquet
, “
Scaling behavior for ionic transport and its fluctuations in individual carbon nanotubes
,”
Phys. Rev. Lett.
116
,
154501
(
2016
).
22.
H.
Amiri
,
K. L.
Shepard
,
C.
Nuckolls
, and
R.
Hernández Sánchez
, “
Single-walled carbon nanotubes: Mimics of biological ion channels
,”
Nano Lett.
17
,
1204
(
2017
).
23.
P.
Pang
,
J.
He
,
J. H.
Park
,
P. S.
Krstić
, and
S.
Lindsay
, “
Origin of giant ionic currents in carbon nanotube channels
,”
ACS Nano
5
,
7277
(
2011
).
24.
Y.-C.
Yao
,
A.
Taqieddin
,
M. A.
Alibakhshi
,
M.
Wanunu
,
N. R.
Aluru
, and
A.
Noy
, “
Strong electroosmotic coupling dominates ion conductance of 1.5 nm diameter carbon nanotube porins
,”
ACS Nano
13
,
12851
(
2019
).
25.
R. H.
Tunuguntla
,
R. Y.
Henley
,
Y.-C.
Yao
,
T. A.
Pham
,
M.
Wanunu
, and
A.
Noy
, “
Enhanced water permeability and tunable ion selectivity in subnanometer carbon nanotube porins
,”
Science
357
,
792
(
2017
).
26.
J.
Wu
,
K.
Gerstandt
,
H.
Zhang
,
J.
Liu
, and
B. J.
Hinds
, “
Electrophoretically induced aqueous flow through single-walled carbon nanotube membranes
,”
Nat. Nanotechnol.
7
,
133
(
2012
).
27.
K.
Yazda
,
S.
Tahir
,
T.
Michel
,
B.
Loubet
,
M.
Manghi
,
J.
Bentin
,
F.
Picaud
,
J.
Palmeri
,
F.
Henn
, and
V.
Jourdain
, “
Voltage-activated transport of ions through single-walled carbon nanotubes
,”
Nanoscale
9
,
11976
(
2017
).
28.
J.
Geng
,
K.
Kim
,
J.
Zhang
,
A.
Escalada
,
R.
Tunuguntla
,
L. R.
Comolli
,
F. I.
Allen
,
A. V.
Shnyrova
,
K. R.
Cho
,
D.
Munoz
,
Y. M.
Wang
,
C. P.
Grigoropoulos
,
C. M.
Ajo-Franklin
,
V. A.
Frolov
, and
A.
Noy
, “
Stochastic transport through carbon nanotubes in lipid bilayers and live cell membranes
,”
Nature
514
,
612
(
2014
).
29.
X.
Gao
,
T.
Zhao
, and
Z.
Li
, “
Fluid breakup in carbon nanotubes: An explanation of ultrafast ion transport
,”
Phys. Fluids
29
,
092003
(
2017
).
30.
P.
Biesheuvel
and
M.
Bazant
, “
Analysis of ionic conductance of carbon nanotubes
,”
Phys. Rev. E
94
,
050601
(
2016
).
31.
J. A.
Thomas
and
A. J.
McGaughey
, “
Water flow in carbon nanotubes: Transition to subcontinuum transport
,”
Phys. Rev. Lett.
102
,
184502
(
2009
).
32.
J. A.
Thomas
and
A. J. H.
McGaughey
, “
Density, distribution, and orientation of water molecules inside and outside carbon nanotubes
,”
J. Chem. Phys.
128
,
084715
(
2008
).
33.
A. I.
Kolesnikov
,
J.-M.
Zanotti
,
C.-K.
Loong
,
P.
Thiyagarajan
,
A. P.
Moravsky
,
R. O.
Loutfy
, and
C. J.
Burnham
, “
Anomalously soft dynamics of water in a nanotube: A revelation of nanoscale confinement
,”
Phys. Rev. Lett.
93
,
035503
(
2004
).
34.
J.
Mo
,
L.
Li
,
J.
Zhou
,
D.
Xu
,
B.
Huang
, and
Z.
Li
, “
Fluid infiltration pressure for hydrophobic nanochannels
,”
Phys. Rev. E
91
,
033022
(
2015
).
35.
S. S.
Wong
,
E.
Joselevich
,
A. T.
Woolley
,
C. L.
Cheung
, and
C. M.
Lieber
, “
Covalently functionalized nanotubes as nanometre- sized probes in chemistry and biology
,”
Nature
394
,
52
(
1998
).
36.
X.
Zhang
,
W.
Zhou
,
F.
Xu
,
M.
Wei
, and
Y.
Wang
, “
Resistance of water transport in carbon nanotube membranes
,”
Nanoscale
10
,
13242
(
2018
).
37.
Y.
Li
,
W.
Kim
,
Y.
Zhang
,
M.
Rolandi
,
D.
Wang
, and
H.
Dai
, “
Growth of single-walled carbon nanotubes from discrete catalytic nanoparticles of various sizes
,”
J. Phys. Chem. B
105
,
11424
(
2001
).
38.
D.
Lin
,
S.
Zhang
,
W.
Liu
,
Y.
Yu
, and
J.
Zhang
, “
Carburization of Fe/Ni catalyst for efficient growth of single‐walled carbon nanotubes
,”
Small
15
,
1902240
(
2019
).
39.
A.
Jorio
,
A.
Souza Filho
,
G.
Dresselhaus
,
M.
Dresselhaus
,
A.
Swan
,
M.
Ünlü
,
B.
Goldberg
,
M.
Pimenta
,
J.
Hafner
, and
C.
Lieber
, “
G-band resonant Raman study of 62 isolated single-wall carbon nanotubes
,”
Phys. Rev. B
65
,
155412
(
2002
).
40.
S.
Plimpton
, “
Fast parallel algorithms for short-range molecular dynamics
,”
J. Comput. Phys.
117
,
1
(
1995
).
41.
S.
Luo
,
J.
Wang
, and
Z.
Li
, “
Homogeneous ice nucleation under shear
,”
J. Phys. Chem. B
124
,
3701
3708
(
2020
).
42.
B. V.
Raghavan
and
M.
Ostoja-Starzewski
, “
Shear-thinning of molecular fluids in Couette flow
,”
Phys. Fluids
29
,
023103
(
2017
).
43.
Y.
Jin
,
T.
Ng
,
R.
Tao
,
S.
Luo
,
Y.
Su
, and
Z.
Li
, “
Coupling effects in electromechanical ion transport in graphene nanochannels
,”
Phys. Rev. E
102
,
033112
(
2020
).
44.
W. L.
Jorgensen
,
D. S.
Maxwell
, and
J.
Tirado-Rives
, “
Development and testing of the OPLS all-atom force field on conformational energetics and properties of organic liquids
,”
J. Am. Chem. Soc.
118
,
11225
(
1996
).
45.
H. J. C.
Berendsen
,
J. R.
Grigera
, and
T. P.
Straatsma
, “
The missing term in effective pair potentials
,”
J. Phys. Chem. A
91
,
6269
(
1987
).
46.
I. S.
Joung
and
T. E.
Cheatham
 III
, “
Determination of alkali and halide monovalent ion parameters for use in explicitly solvated biomolecular simulations
,”
J. Phys. Chem. B
112
,
9020
(
2008
).
47.
E.
Chełmecka
,
K.
Pasterny
,
T.
Kupka
, and
L.
Stobiński
, “
DFT studies of COOH tip-functionalized zigzag and armchair single wall carbon nanotubes
,”
J. Mol. Model.
18
,
2241
(
2012
).
48.
A.
Grossfield
, WHAM: The weighted histogram analysis method, version 2.06,
2012
.
49.
T. K.
Rostovtseva
,
V. M.
Aguilella
,
I.
Vodyanoy
,
S. M.
Bezrukov
, and
V. A.
Parsegian
, “
Membrane surface-charge titration probed by gramicidin A channel conductance
,”
Biophys. J.
75
,
1783
(
1998
).
50.
B. W.
Urban
,
S. B.
Hladky
, and
D. A.
Haydon
, “
Ion movements in gramicidin pores. An example of single-file transport
,”
Biochim. Biophys. Acta Biomembr.
602
,
331
(
1980
).
51.
E.
Neher
,
J.
Sandblom
, and
G.
Eisenman
, “
Ionic selectivity, saturation, and block in gramicidin A channels
,”
J. Membr. Biol.
40
,
97
(
1978
).
52.
Y.
Noh
and
N. R.
Aluru
, “
Ion transport in electrically imperfect nanopores
,”
ACS Nano
14
,
10518
(
2020
).
53.
S.
Joseph
,
R. J.
Mashl
,
E.
Jakobsson
, and
N. R.
Aluru
, “
Electrolytic transport in modified carbon nanotubes
,”
Nano Lett.
3
,
1399
(
2003
).
54.
C.
Fang
,
Z.
Yu
, and
R.
Qiao
, “
Impact of surface ionization on water transport and salt leakage through graphene oxide membranes
,”
J. Phys. Chem. C
121
,
13412
(
2017
).
55.
I.
Kosińska
, “
How the asymmetry of internal potential influences the shape of I–V characteristic of nanochannels
,”
J. Chem. Phys.
124
,
244707
(
2006
).
56.
A.
Fuliński
,
I.
Kosińska
, and
Z.
Siwy
, “
On the validity of continuous modelling of ion transport through nanochannels
,”
Europhys. Lett.
67
,
683
(
2004
).
57.
M.
Przybylski
,
M. O.
Glocker
,
U.
Nestel
,
V.
Schnaible
,
M.
Blüggel
,
K.
Diederichs
,
J.
Weckesser
,
M.
Schad
,
A.
Schmid
, and
W.
Welte
, “
X-ray crystallographic and mass spectrometric structure determination and functional characterization of succinylated porin from Rhodobacter capsulatus: Implications for ion selectivity and single-channel conductance
,”
Protein Sci.
5
,
1477
(
1996
).
58.
B.
Nadler
,
Z.
Schuss
,
U.
Hollerbach
, and
R.
Eisenberg
, “
Saturation of conductance in single ion channels: The blocking effect of the near reaction field
,”
Phys. Rev. E
70
,
051912
(
2004
).
59.
R. S.
Eisenberg
,
M. M.
Kl/osek
, and
Z.
Schuss
, “
Diffusion as a chemical reaction: Stochastic trajectories between fixed concentrations
,”
J. Chem. Phys.
102
,
1767
(
1995
).

Supplementary Material

You do not currently have access to this content.