Using both analytic and numerical analyses of the Poisson–Nernst–Planck equations, we theoretically investigate the electric conductivity of a conical channel which, in accordance with recent experiments, exhibits a strong non-linear pressure dependence. This mechanosensitive diodic behavior stems from the pressure-sensitive build-up or depletion of salt in the pore. From our analytic results, we find that the optimal geometry for this diodic behavior strongly depends on the flow rate with the ideal ratio of tip-to-base-radii being equal to 0.22 at zero-flow. With increased flow, this optimal ratio becomes smaller and, simultaneously, the diodic performance becomes weaker. Consequently an optimal diode is obtained at zero-flow, which is realized by applying a pressure drop that is proportional to the applied potential and to the inverse square of the tip radius, thereby countering electro-osmotic flow. When the applied pressure deviates from this ideal pressure drop the diodic performance falls sharply, explaining the dramatic mechanosensitivity observed in experiments.

1.
Z.
Zhang
,
L.
Wen
, and
L.
Jiang
, “
Nanofluidics for osmotic energy conversion
,”
Nat. Rev. Mater.
6
,
622
(
2021
).
2.
D.-K.
Kim
,
C.
Duan
,
Y.-F.
Chen
, and
A.
Majumdar
, “
Power generation from concentration gradient by reverse electrodialysis in ion-selective nanochannels
,”
Microfluid. Nanofluid.
9
,
1215
(
2010
).
3.
A.
Siria
,
P.
Poncharal
,
A.-L.
Biance
,
R.
Fulcrand
,
X.
Blase
,
S. T.
Purcell
, and
L.
Bocquet
, “
Giant osmotic energy conversion measured in a single transmembrane boron nitride nanotube
,”
Nature
494
,
455
(
2013
).
4.
A.
Siria
,
M.-L.
Bocquet
, and
L.
Bocquet
, “
New avenues for the large-scale harvesting of blue energy
,”
Nat. Rev. Chem.
1
,
0091
(
2017
).
5.
M.
Elimelech
and
W. A.
Phillip
, “
The future of seawater desalination: Energy, technology, and the environment
,”
Science
333
,
712
(
2011
).
6.
A.
Campione
,
L.
Gurreri
,
M.
Ciofalo
,
G.
Micale
,
A.
Tamburini
, and
A.
Cipollina
, “
Electrodialysis for water desalination: A critical assessment of recent developments on process fundamentals, models and applications
,”
Desalination
434
,
121
(
2018
).
7.
X.
Wang
,
C.
Cheng
,
S.
Wang
, and
S.
Liu
, “
Electroosmotic pumps and their applications in microfluidic systems
,”
Microfluid. Nanofluid.
6
,
145
(
2009
).
8.
T. M.
Squires
and
S. R.
Quake
, “
Microfluidics: Fluid physics at the nanoliter scale
,”
Rev. Mod. Phys.
77
,
977
(
2005
).
9.
L.
Bocquet
and
E.
Charlaix
, “
Nanofluidics, from bulk to interfaces
,”
Chem. Soc. Rev.
39
,
1073
(
2010
).
10.
R. B.
Schoch
,
J.
Han
, and
P.
Renaud
, “
Transport phenomena in nanofluidics
,”
Rev. Mod. Phys.
80
,
839
(
2008
).
11.
J. C.
Eijkel
and
A.
van den Berg
, “
Nanofluidics: What is it and what can we expect from it?
,”
Microfluid. Nanofluid.
1
,
249
(
2005
).
12.
B. L.
Werkhoven
,
J. C.
Everts
,
S.
Samin
, and
R.
van Roij
, “
Flow-induced surface charge heterogeneity in electrokinetics due to stern-layer conductance coupled to reaction kinetics
,”
Phys. Rev. Lett.
120
,
264502
(
2018
).
13.
B. L.
Werkhoven
,
S.
Samin
, and
R.
van Roij
, “
Dynamic Stern layers in charge-regulating electrokinetic systems: Three regimes from an analytical approach
,”
Eur. Phys. J. Spec. Top.
227
,
2539
(
2019
).
14.
P.
Ober
,
W. Q.
Boon
,
M.
Dijkstra
,
E. H.
Backus
,
R.
van Roij
, and
M.
Bonn
, “
Liquid flow reversibly creates a macroscopic surface charge gradient
,”
Nat. Commun.
12
(
1
),
4102
(
2021
).
15.
S.
Levine
,
J.
Marriott
,
G.
Neale
, and
N.
Epstein
, “
Theory of electrokinetic flow in fine cylindrical capillaries at high zeta-potentials
,”
J. Colloid Interface Sci.
52
,
136
(
1975
).
16.
M.
Sadeghi
,
M. H.
Saidi
, and
A.
Sadeghi
, “
Electroosmotic flow and ionic conductance in a pH-regulated rectangular nanochannel
,”
Phys. Fluids
29
,
062002
(
2017
).
17.
M.
Sadeghi
,
M. H.
Saidi
,
A.
Moosavi
, and
A.
Sadeghi
, “
Geometry effect on electrokinetic flow and ionic conductance in pH-regulated nanochannels
,”
Phys. Fluids
29
,
122006
(
2017
).
18.
S.
Chanda
and
P. A.
Tsai
, “
Competition between electroosmotic and chemiosmotic flow in charged nanofluidics
,”
Phys. Fluids
33
(
3
),
032008
(
2021
).
19.
N.
Laohakunakorn
,
V. V.
Thacker
,
M.
Muthukumar
, and
U. F.
Keyser
, “
Electroosmotic flow reversal outside glass nanopores
,”
Nano Lett.
15
,
695
(
2015
).
20.
W.-J.
Lan
,
M. A.
Edwards
,
L.
Luo
,
R. T.
Perera
,
X.
Wu
,
C. R.
Martin
, and
H. S.
White
, “
Voltage-rectified current and fluid flow in conical nanopores
,”
Acc. Chem. Res.
49
,
2605
(
2016
).
21.
G. W.
Bishop
,
M. M.
Lopez
, Jr.
,
P.
Ramiah Rajasekaran
,
X.
Wu
, and
C. R.
Martin
, “
Electroosmotic flow rectification in membranes with asymmetrically shaped pores: Effects of current and pore density
,”
J. Phys. Chem. C
119
,
16633
(
2015
).
22.
Z.
Asghar
,
M.
Waqas
,
M. A.
Gondal
, and
W. A.
Khan
, “
Electro-osmotically driven generalized Newtonian blood flow in a divergent micro-channel
,”
Alexandria Eng. J.
61
,
4519
(
2022
).
23.
Z.
Asghar
,
M. W.
Saeed Khan
,
M. A.
Gondal
, and
A.
Ghaffari
, “
Channel flow of non-Newtonian fluid due to peristalsis under external electric and magnetic field
,”
Proc. Inst. Mech. Eng., Part E
(published online
2022
).
24.
H. S.
White
and
A.
Bund
, “
Ion current rectification at nanopores in glass membranes
,”
Langmuir
24
,
2212
(
2008
).
25.
C.
Wen
,
S.
Zeng
,
S.
Li
,
Z.
Zhang
, and
S.-L.
Zhang
, “
On rectification of ionic current in nanopores
,”
Anal. Chem.
91
,
14597
(
2019
).
26.
J. E.
Proctor
, “
Theory of ion transport and ion current rectification in nanofluidic diodes
,”
MSc thesis
(
Clemson University
,
2021
).
27.
D.
Woermann
, “
Electrochemical transport properties of a cone-shaped nanopore: High and low electrical conductivity states depending on the sign of an applied electrical potential difference
,”
Phys. Chem. Chem. Phys.
5
,
1853
(
2003
).
28.
D.
Woermann
, “
Electrochemical transport properties of a cone-shaped nanopore: Revisited
,”
Phys. Chem. Chem. Phys.
6
,
3130
(
2004
).
29.
M. L.
Kovarik
,
K.
Zhou
, and
S. C.
Jacobson
, “
Effect of conical nanopore diameter on ion current rectification
,”
J. Phys. Chem. B
113
,
15960
(
2009
).
30.
C.-Y.
Lin
,
L.-H.
Yeh
, and
Z. S.
Siwy
, “
Voltage-induced modulation of ionic concentrations and ion current rectification in mesopores with highly charged pore walls
,”
J. Phys. Chem. Lett.
9
,
393
(
2018
).
31.
I.
Vlassiouk
,
T. R.
Kozel
, and
Z. S.
Siwy
, “
Biosensing with nanofluidic diodes
,”
J. Am. Chem. Soc.
131
,
8211
(
2009
).
32.
S. N.
Bush
,
T. T.
Volta
, and
C. R.
Martin
, “
Chemical sensing and chemoresponsive pumping with conical-pore polymeric membranes
,”
Nanomaterials
10
,
571
(
2020
).
33.
X.
Hou
,
W.
Guo
, and
L.
Jiang
, “
Biomimetic smart nanopores and nanochannels
,”
Chem. Soc. Rev.
40
,
2385
(
2011
).
34.
A.
Piruska
,
M.
Gong
,
J. V.
Sweedler
, and
P. W.
Bohn
, “
Nanofluidics in chemical analysis
,”
Chem. Soc. Rev.
39
,
1060
(
2010
).
35.
M.
Gholinejad
,
A. J.
Moghadam
, and
S. A.
Mousavi Shaegh
, “
Analysis of preconcentration patterns in microfluidic ion concentration polarization devices
,”
Phys. Fluids
34
,
012014
(
2022
).
36.
M.
Gholinejad
,
A.
Jabari Moghadam
,
D.-T.
Phan
,
A. K.
Miri
, and
S. A.
Mousavi Shaegh
, “
Design and application of ion concentration polarization for preconcentrating charged analytes
,”
Phys. Fluids
33
,
051301
(
2021
).
37.
M.
Gholinejad
,
A.
Jabari Moghadam
,
S. A.
Mousavi Shaegh
, and
A. K.
Miri
, “
Multifactorial analysis of ion concentration polarization for microfluidic preconcentrating applications using response surface method
,”
Phys. Fluids
32
,
072012
(
2020
).
38.
Y.
Gong
,
C.
Zhang
,
X.
Weng
,
B.
Peng
, and
H.
Jiang
, “
Electrokinetically induced concentration of diluted sample by liquid metal embedded microfluidic chip
,”
Phys. Fluids
34
,
022006
(
2022
).
39.
C.
Li
,
T.
Xiong
,
P.
Yu
,
J.
Fei
, and
L.
Mao
, “
Synaptic iontronic devices for brain-mimicking functions: Fundamentals and applications
,”
ACS Appl. Bio Mater.
4
,
71
(
2021
).
40.
S.
Ghosal
,
J. D.
Sherwood
, and
H.-C.
Chang
, “
Solid-state nanopore hydrodynamics and transport
,”
Biomicrofluidics
13
,
011301
(
2019
).
41.
H.
Chun
and
T. D.
Chung
, “
Iontronics
,”
Annu. Rev. Anal. Chem.
8
,
441
(
2015
).
42.
J.
Jung
,
J.
Kim
,
J.
Lee
,
Y.-W.
Oh
,
S.
Jung
,
I.-S.
Kang
, and
K.
Choi
, “
Modulation of ionic current rectification direction for biomimetic aluminum oxide membrane by surface modification
,”
AIP Adv.
12
,
035141
(
2022
).
43.
C. D.
Cox
,
N.
Bavi
, and
B.
Martinac
, “
Biophysical principles of ion-channel-mediated mechanosensory transduction
,”
Cell Rep.
29
(
1
),
1
(
2019
).
44.
A.
Anishkin
,
S. H.
Loukin
,
J.
Teng
, and
C.
Kung
, “
Feeling the hidden mechanical forces in lipid bilayer is an original sense
,”
Proc. Natl. Acad. Sci. U. S. A.
111
,
7898
(
2014
).
45.
F.
Qian
,
W.
Zhang
,
D.
Huang
,
W.
Li
,
Q.
Wang
, and
C.
Zhao
, “
Electrokinetic power generation in conical nanochannels: Regulation effects due to conicity
,”
Phys. Chem. Chem. Phys.
22
,
2386
(
2020
).
46.
L.
Jubin
,
A.
Poggioli
,
A.
Siria
, and
L.
Bocquet
, “
Dramatic pressure-sensitive ion conduction in conical nanopores
,”
Proc. Natl. Acad. Sci. U. S. A.
115
,
4063
(
2018
).
47.
D.
Pandey
and
S.
Bhattacharyya
, “
Influence of finite ion size and dielectric decrement on the ion current rectification in a single conical nanopore
,”
Phys. Fluids
33
,
062006
(
2021
).
48.
W.-J.
Lan
,
D. A.
Holden
, and
H. S.
White
, “
Pressure-dependent ion current rectification in conical-shaped glass nanopores
,”
J. Am. Chem. Soc.
133
,
13300
(
2011
).
49.
C.
Kubeil
and
A.
Bund
, “
The role of nanopore geometry for the rectification of ionic currents
,”
J. Phys. Chem. C
115
,
7866
(
2011
).
50.
I.
Vlassiouk
,
S.
Smirnov
, and
Z.
Siwy
, “
Nanofluidic ionic diodes. Comparison of analytical and numerical solutions
,”
ACS Nano
2
,
1589
(
2008
).
51.
P.
Ramirez
,
P. Y.
Apel
,
J.
Cervera
, and
S.
Mafé
, “
Pore structure and function of synthetic nanopores with fixed charges: Tip shape and rectification properties
,”
Nanotechnology
19
,
315707
(
2008
).
52.
J.
Cervera
,
B.
Schiedt
,
R.
Neumann
,
S.
Mafé
, and
P.
Ramírez
, “
Ionic conduction, rectification, and selectivity in single conical nanopores
,”
J. Chem. Phys.
124
,
104706
(
2006
).
53.
D.-H.
Lin
,
C.-Y.
Lin
,
S.
Tseng
, and
J.-P.
Hsu
, “
Influence of electroosmotic flow on the ionic current rectification in a pH-regulated, conical nanopore
,”
Nanoscale
7
,
14023
(
2015
).
54.
J.-P.
Hsu
,
S.-T.
Yang
,
C.-Y.
Lin
, and
S.
Tseng
, “
Ionic current rectification in a conical nanopore: Influences of electroosmotic flow and type of salt
,”
J. Phys. Chem. C
121
,
4576
(
2017
).
55.
Y.
Ai
,
M.
Zhang
,
S. W.
Joo
,
M. A.
Cheney
, and
S.
Qian
, “
Effects of electroosmotic flow on ionic current rectification in conical nanopores
,”
J. Phys. Chem. C
114
,
3883
(
2010
).
56.
W.
Brown
,
M.
Kvetny
,
R.
Yang
, and
G.
Wang
, “
Higher ion selectivity with lower energy usage promoted by electro-osmotic flow in the transport through conical nanopores
,”
J. Phys. Chem. C
125
,
3269
(
2021
).
57.
M.
Aarts
,
W.
Boon
,
B.
Cuénod
,
M.
Dijkstra
,
R.
van Roij
, and
E.
Alarcon-Llado
, arXiv:2206.14594 (
2022
).
58.
E.
Choi
,
C.
Wang
,
G. T.
Chang
, and
J.
Park
, “
High current ionic diode using homogeneously charged asymmetric nanochannel network membrane
,”
Nano Lett.
16
,
2189
(
2016
).
59.
S.
Dal Cengio
and
I.
Pagonabarraga
, “
Confinement-controlled rectification in a geometric nanofluidic diode
,”
J. Chem. Phys.
151
,
044707
(
2019
).
60.
A. R.
Poggioli
,
A.
Siria
, and
L.
Bocquet
, “
Beyond the tradeoff: Dynamic selectivity in ionic transport and current rectification
,”
J. Phys. Chem. B
123
,
1171
(
2019
).
61.
F.
Xiang
,
W.
Zhang
,
X.
Yang
, and
S.
Liang
, “
Ionic current rectification: A result of the series connection of nanochannels with different Dukhin numbers
,”
J. Phys. Chem. B
126
,
1779
(
2022
).
62.
A. W.
Adamson
and
A. P.
Gast
,
Physical Chemistry of Surfaces
(
Interscience Publishers
,
New York
,
1967
), Vol.
150
.
63.
R. K.
Iler
,
The Colloid Chemistry of Silica and Silicates
(
Cornell University Press
,
1955
), Vol.
80
.
64.
M.-S.
Chun
,
S.-Y.
Lee
, and
S.-M.
Yang
, “
Estimation of zeta potential by electrokinetic analysis of ionic fluid flows through a divergent microchannel
,”
J. Colloid Interface Sci.
266
,
120
(
2003
).
65.
J.
Happel
and
H.
Brenner
,
Low Reynolds Number Hydrodynamics: With Special Applications to Particulate Media
(
Springer Science & Business Media
,
2012
), Vol.
1
.
66.
T. E
Veenstra
, “
Strongly non-linear pressure-induced ion currents in conical nanopores
,”
BSc thesis
(
Utrecht University
,
2020
).
67.
B. L.
Werkhoven
and
R.
van Roij
, “
Coupled water, charge and salt transport in heterogeneous nano-fluidic systems
,”
Soft Matter
16
,
1527
(
2020
).
68.
M. W.
Khan
,
M. A.
Memon
,
M. N.
Khan
, and
M. M.
Khan
, “
Traffic noise pollution in Karachi, Pakistan
,”
J. Liaquat Univ. Med. Health Sci.
9
,
114
(
2010
).
69.
D. A.
Bies
,
C. H.
Hansen
, and
C. Q.
Howard
,
Engineering Noise Control
(
CRC Press
,
2017
).
70.
J. M.
Perry
,
K.
Zhou
,
Z. D.
Harms
, and
S. C.
Jacobson
, “
Ion transport in nanofluidic funnels
,”
ACS Nano
4
,
3897
(
2010
).
71.
A.
Marcotte
,
T.
Mouterde
,
A.
Niguès
,
A.
Siria
, and
L.
Bocquet
, “
Mechanically activated ionic transport across single-digit carbon nanotubes
,”
Nat. Mater.
19
,
1057
(
2020
).
72.
P.
Robin
,
N.
Kavokine
, and
L.
Bocquet
, “
Modeling of emergent memory and voltage spiking in ionic transport through angstrom-scale slits
,”
Science
373
,
687
(
2021
).

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