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Xiao K, Zhou Y, Kong XY, Xie G, Li P, Zhang Z, Wen L, Jiang L. Electrostatic-Charge- and Electric-Field-Induced Smart Gating for Water Transportation. ACS NANO 2016; 10:9703-9709. [PMID: 27648730 DOI: 10.1021/acsnano.6b05682] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Regulating and controlling the transport of water across nanochannels is of great importance in both fundamental research and practical applications because it is difficult to externally control water flow through nanochannels as in biological channels. To date, only a few hydrophobic nanochannels controlling the transport of water have been reported, all of which use exotic hydrophobic molecules. However, the effect of electrostatic charges, which plays an indispensable role in membrane proteins and dominates the energetics of water permeation across aquaporins, has not gained enough attention to control water transport through a solid-state nanochannel/nanopore. Here, we report electrostatic-charge-induced water gating of a single ion track-etched sub-10 nm channel. This system can directly realize the gating transition between an open, conductive state and a closed, nonconductive state by regulating the surface charge density through a process that involves alternating capillary evaporation and capillary condensation. Compared to the introduction of exotic hydrophobic molecules, water gating controlled by electrostatic charges is simple, convenient, and effective. Such a system anticipates potential applications including desalination, controllable valves, and drug delivery systems.
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Affiliation(s)
- Kai Xiao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Green Printing, Institute of Chemistry, and ‡Key Laboratory of Bioinspired Smart Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing, 100190, People's Republic of China
| | - Yahong Zhou
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Green Printing, Institute of Chemistry, and ‡Key Laboratory of Bioinspired Smart Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing, 100190, People's Republic of China
| | - Xiang-Yu Kong
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Green Printing, Institute of Chemistry, and ‡Key Laboratory of Bioinspired Smart Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing, 100190, People's Republic of China
| | - Ganhua Xie
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Green Printing, Institute of Chemistry, and ‡Key Laboratory of Bioinspired Smart Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing, 100190, People's Republic of China
| | - Pei Li
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Green Printing, Institute of Chemistry, and ‡Key Laboratory of Bioinspired Smart Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing, 100190, People's Republic of China
| | - Zhen Zhang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Green Printing, Institute of Chemistry, and ‡Key Laboratory of Bioinspired Smart Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing, 100190, People's Republic of China
| | - Liping Wen
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Green Printing, Institute of Chemistry, and ‡Key Laboratory of Bioinspired Smart Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing, 100190, People's Republic of China
| | - Lei Jiang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Green Printing, Institute of Chemistry, and ‡Key Laboratory of Bioinspired Smart Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing, 100190, People's Republic of China
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Innes L, Gutierrez D, Mann W, Buchsbaum SF, Siwy ZS. Presence of electrolyte promotes wetting and hydrophobic gating in nanopores with residual surface charges. Analyst 2015; 140:4804-12. [DOI: 10.1039/c4an02244k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Single nanopores containing hydrophobic and hydrophilic islands on the pore walls exhibit salt concentration modulated hydrophobic gating, with more concentrated solutions promoting wetting.
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Affiliation(s)
- Laura Innes
- Department of Physics and Astronomy
- University of California
- Irvine
- USA
| | - Diego Gutierrez
- Department of Physics and Astronomy
- University of California
- Irvine
- USA
- Department of Physics
| | - William Mann
- Department of Physics and Astronomy
- University of California
- Irvine
- USA
- Department of Physics
| | | | - Zuzanna S. Siwy
- Department of Physics and Astronomy
- University of California
- Irvine
- USA
- Department of Chemistry
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Powell MR, Cleary L, Davenport M, Shea KJ, Siwy ZS. Electric-field-induced wetting and dewetting in single hydrophobic nanopores. NATURE NANOTECHNOLOGY 2011; 6:798-802. [PMID: 22036811 DOI: 10.1038/nnano.2011.189] [Citation(s) in RCA: 209] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 09/28/2011] [Indexed: 05/22/2023]
Abstract
The behaviour of water in nanopores is very different from that of bulk water. Close to hydrophobic surfaces, the water density has been found to be lower than in the bulk, and if confined in a sufficiently narrow hydrophobic nanopore, water can spontaneously evaporate. Molecular dynamics simulations have suggested that a nanopore can be switched between dry and wet states by applying an electric potential across the nanopore membrane. Nanopores with hydrophobic walls could therefore create a gate system for water, and also for ionic and neutral species. Here, we show that single hydrophobic nanopores can undergo reversible wetting and dewetting due to condensation and evaporation of water inside the pores. The reversible process is observed as fluctuations between conducting and non-conducting ionic states and can be regulated by a transmembrane electric potential.
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Kim J, Byun D, Hong J. Novel method of generating water-in-oil(W∕O) droplets in a microchannel with grooved walls. BIOMICROFLUIDICS 2011; 5:14106. [PMID: 21483660 PMCID: PMC3073009 DOI: 10.1063/1.3567102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 02/17/2011] [Indexed: 05/30/2023]
Abstract
We present a novel method of generating and retrieving droplets stored in microfluidic grooves or cavity structures. First we designed and fabricated polydimethylsiloxane microchannels with grooves on the walls and then produced a two-phase flow of oil and aqueous phases to form aqueous phase droplets in an oil state. We propose the following three mechanisms of droplet generation: the contact line on the groove wall continues moving along the wall and descends to the bottom of the cavity, confining the aqueous phase in the cavity; once the interface between the oil and aqueous phases moves into the cavity, the interface contacts the top of the neighboring groove; and a spherical droplet forms at the corner in the cavity due to surface tension. The viscosity of the oil phase and the surface tension of the interface determine whether a droplet can be generated. Then, we could adjust the velocity of the interface and the aspect ratio of the cavity to achieve the optimal conditions for generating the single droplet. We observed that the largest droplet is stably generated without a daughter droplet at typical values of free-stream velocity (10 μl∕min) and groove pitch 110 μm for all three cases with different oil phases (20, 50, and 84 cP). This technique is expected to serve as a platform for droplet-based reaction systems, particularly with regard to monitoring cell behavior, in vitro expression, and possibly even micropolymerase chain reaction chambers.
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Parikesit GOF, Vrouwe EX, Blom MT, Westerweel J. Observation of hydrophobic-like behavior in geometrically patterned hydrophilic microchannels. BIOMICROFLUIDICS 2010; 4:44103. [PMID: 21042432 PMCID: PMC2966485 DOI: 10.1063/1.3499416] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 09/18/2010] [Indexed: 05/07/2023]
Abstract
We present our observation of meta-hydrophobicity, where geometrically patterned surfaces make hydrophilic microchannels exhibit hydrophobic-like behaviors. We analyze the wetting-induced energy decrease that results from the surface geometries and experimentally demonstrate how those geometries can modulate the dynamics of capillary-driven wetting and evaporation-driven drying of microfluidic systems. Our results also show that the modulated wetting dynamics can be employed to generate regulated patterns of microbubbles.
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