Geometrical control of ionic current rectification in a configurable nanofluidic diode.
Control of ionic current in a nanofluidic system and development of the elements analogous to electrical circuits have been the subject of theoretical and experimental investigations over the past decade. Here, we theoretically and experimentally explore a new technique for rectification of ionic current using asymmetric 2D nanochannels. These nanochannels have a rectangular cross section and a stepped structure consisting of a shallow and a deep side. Control of height and length of each side enables us to obtain optimum rectification at each ionic strength. A 1D model based on the Poisson-Nernst-Planck equation is derived and validated against the full 2D numerical solution, and a nondimensional concentration is presented as a function of nanochannel dimensions, surface charge, and the electrolyte concentration that summarizes the rectification behavior of such geometries. The rectification factor reaches a maximum at certain electrolyte concentration predicted by this nondimensional number and decays away from it. This method of fabrication and control of a nanofluidic diode does not require modification of the surface charge and facilitates the integration with lab-on-a-chip fluidic circuits. Experimental results obtained from the stepped nanochannels are in good agreement with the 1D theoretical model.
Department of Mechanical Engineering, Boston University , Boston, Massachusetts 02215, USA.
Mohammad Amin
MA
Alibakhshi
School of Aerospace Engineering, Tsinghua University , Beijing 100084, China.
Binqi
0000-0002-4103-1589
B
Liu
Applied Mechanics Laboratory, Department of Engineering Mechanics and Center for Nano and Micro Mechanics, Tsinghua University , Beijing 100084, China.
Zhiping
Z
Xu
Department of Mechanical Engineering, Boston University , Boston, Massachusetts 02215, USA.
Chuanhua
C
Duan
Phys Rev E Stat Nonlin Soft Matter Phys. 2007 Oct;76(4 Pt 1):041202
17994972
Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Apr;79(4 Pt 2):046305
19518331
Phys Rev Lett. 2007 Jul 27;99(4):044501
17678369
J Am Chem Soc. 2009 Jun 17;131(23):8211-20
19507907
J Chem Phys. 2013 Jan 28;138(4):044706
23387614
Nano Lett. 2007 Mar;7(3):552-6
17311462
Phys Rev E Stat Nonlin Soft Matter Phys. 2015 Sep;92(3):033018
26465567
J Colloid Interface Sci. 2011 Aug 1;360(1):262-71
21546029
J Am Chem Soc. 2004 Sep 8;126(35):10850-1
15339163
ACS Nano. 2008 Aug;2(8):1589-602
19206361
Phys Rev Lett. 2015 Sep 25;115(13):134503
26451560
J Phys Chem B. 2006 Oct 26;110(42):21205-9
17048946
Nano Lett. 2009 Nov;9(11):3820-5
19603791
Nano Lett. 2006 Jan;6(1):89-95
16402793
Lab Chip. 2016 Apr 7;16(7):1171-7
26960551
Phys Rev Lett. 2009 Oct 9;103(15):154502
19905643
J Chem Phys. 2015 Dec 14;143(22):224705
26671394
J Colloid Interface Sci. 2008 Sep 15;325(2):526-38
18639883
Anal Chem. 2009 Apr 15;81(8):3128-33
19298060
Anal Chem. 2014 Nov 18;86(22):11174-80
25365680
Sci Rep. 2016 Apr 26;6:24936
27112404
Biosens Bioelectron. 2013 Dec 15;50:78-83
23835221
Phys Rev Lett. 2004 Jul 16;93(3):035901
15323836
ACS Nano. 2016 Mar 22;10 (3):3214-21
26816294
Nano Lett. 2005 May;5(5):943-8
15884899
Nat Commun. 2011 Oct 18;2:506
22009038
Annu Rev Anal Chem (Palo Alto Calif). 2014;7:317-35
24818814
Nano Lett. 2005 Nov;5(11):2274-80
16277467
Nano Lett. 2007 Sep;7(9):2886-91
17691852
Nano Lett. 2007 Mar;7(3):547-51
17311461
ACS Nano. 2009 Mar 24;3(3):575-84
19220010
Nano Lett. 2007 Oct;7(10):3165-71
17894519