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Zhou R, Neek-Amal M, Peeters FM, Bai B, Sun C. Interlink between Abnormal Water Imbibition in Hydrophilic and Rapid Flow in Hydrophobic Nanochannels. PHYSICAL REVIEW LETTERS 2024; 132:184001. [PMID: 38759191 DOI: 10.1103/physrevlett.132.184001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/29/2024] [Accepted: 03/21/2024] [Indexed: 05/19/2024]
Abstract
Nanoscale extension and refinement of the Lucas-Washburn model is presented with a detailed analysis of recent experimental data and extensive molecular dynamics simulations to investigate rapid water flow and water imbibition within nanocapillaries. Through a comparative analysis of capillary rise in hydrophilic nanochannels, an unexpected reversal of the anticipated trend, with an abnormal peak, of imbibition length below the size of 3 nm was discovered in hydrophilic nanochannels, surprisingly sharing the same physical origin as the well-known peak observed in flow rate within hydrophobic nanochannels. The extended imbibition model is applicable across diverse spatiotemporal scales and validated against simulation results and existing experimental data for both hydrophilic and hydrophobic nanochannels.
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Affiliation(s)
- Runfeng Zhou
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Mehdi Neek-Amal
- Department of Physics, Shahid Rajaee Teacher Training University, 16875-163 Lavizan, Tehran, Iran
- Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
| | - Francois M Peeters
- Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
- Departamento de Física, Universidade Federal do Ceará, Fortaleza-CE 60455-760, Brazil
| | - Bofeng Bai
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Chengzhen Sun
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
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2
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Karna NK, Wohlert J, Hjorth A, Theliander H. Capillary forces exerted by a water bridge on cellulose nanocrystals: the effect of an external electric field. Phys Chem Chem Phys 2023; 25:6326-6332. [PMID: 36779301 DOI: 10.1039/d2cp05563e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Capillary forces play an important role during the dewatering and drying of nanocellulosic materials. Traditional moisture removal techniques, such as heating, have been proved to be deterimental to the properties of these materials and hence, there is a need to develop novel dewatering techniques without affecting the desired properties of materials. It is, therefore, important to explore novel methods for dewatering these high-added-value materials without negatively influencing their properties. In this context, we explore the effect of electric field on the capillary forces developed by a liquid-water bridge between two cellulosic surfaces, which may be formed during the water removal process following its displacement from the interfibrillar spaces. All-atom molecular dynamics (MD) simulations have been used to study the influence of an externally applied electric field on the capillary force exerted by a water bridge. Our results suggest that the equilibrium contact angle of water and the capillary force exerted by the water bridge between two nanocellulosic surfaces depend on the magnitude and direction of the externally applied electric fields. Hence, an external electric field can be applied to manipulate the capillary forces between two particles. The close agreement between the capillary forces measured through MD simulations and those calculated through classical equations indicates that, within the range of the electric field applied in this study, Young-Laplace equations can be safely employed to predict the capillary forces between two particles. The present study provides insights into the use of electric fields for drying of nanocellulosic materials.
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Affiliation(s)
- Nabin Kumar Karna
- Chalmers University of Technology, Chalmersplatsen-4, Sweden. .,Wallenberg Wood Science Center, The Royal Institute of Technology, Chalmers University of Technology and Linköping University, SE-10044 Stockholm, Sweden
| | - Jakob Wohlert
- Wallenberg Wood Science Center, The Royal Institute of Technology, Chalmers University of Technology and Linköping University, SE-10044 Stockholm, Sweden.,KTH Royal Institute of Technology, Stockholm, Sweden
| | - Anna Hjorth
- Chalmers University of Technology, Chalmersplatsen-4, Sweden. .,Wallenberg Wood Science Center, The Royal Institute of Technology, Chalmers University of Technology and Linköping University, SE-10044 Stockholm, Sweden
| | - Hans Theliander
- Chalmers University of Technology, Chalmersplatsen-4, Sweden.
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3
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Garcia Eijo PM, Duriez T, Cabaleiro JM, Artana G. A machine learning-based framework to design capillary-driven networks. LAB ON A CHIP 2022; 22:4860-4870. [PMID: 36377409 DOI: 10.1039/d2lc00843b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We present a novel approach for the design of capillary-driven microfluidic networks using a machine learning genetic algorithm (ML-GA). This strategy relies on a user-friendly 1D numerical tool specifically developed to generate the necessary data to train the ML-GA. This 1D model was validated using analytical results issued from a Y-shaped capillary network and experimental data. For a given microfluidic network, we defined the objective of the ML-GA to obtain the set of geometric parameters that produces the closest matching results against two prescribed curves of delivered volume against time. We performed more than 20 generations of 10 000 simulations to train the ML-GA and achieved the optimal solution of the inverse design problem. The optimisation took less than 6 hours, and the results were successfully validated using experimental data. This work establishes the utility of the presented method for the fast and reliable design of complex capillary-driven devices, enabling users to optimise their designs via an easy-to-use 1D numerical tool and machine learning technique.
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Affiliation(s)
- Pedro Manuel Garcia Eijo
- Laboratorio de Fluidodinámica, Facultad de Ingeniería, Universidad de Buenos Aires, C1063ACV, Buenos Aires, Argentina.
| | - Thomas Duriez
- Laboratorio de Fluidodinámica, Facultad de Ingeniería, Universidad de Buenos Aires, C1063ACV, Buenos Aires, Argentina.
| | - Juan Martín Cabaleiro
- Laboratorio de Fluidodinámica, Facultad de Ingeniería, Universidad de Buenos Aires, C1063ACV, Buenos Aires, Argentina.
| | - Guillermo Artana
- Laboratorio de Fluidodinámica, Facultad de Ingeniería, Universidad de Buenos Aires, C1063ACV, Buenos Aires, Argentina.
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Garcia Eijo PM, Cabaleiro JM, Artana G. Capillary Flow Dynamics in Composite Rectangular Microchannels with Rough Walls. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:13296-13304. [PMID: 36269940 DOI: 10.1021/acs.langmuir.2c02496] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
In this article, we consider rectangular microchannels composed of glass and thin polymeric walls with different roughness in which opposed walls are of the same material but adjacent walls are not. We propose a model for fluid capillary transport into these rectangular microchannels when horizontally positioned and focus our research on how the microchannel aspect ratio modifies the motion during the initial viscous regimes. The model relies on an effective static contact angle and an effective friction coefficient that averages local magnitudes in the cross section. An extensive experimental investigation with different microchannels enabled us to obtain these coefficients for different aspect ratios. While for low aspect ratios, the effective contact angle presents the smallest values, the effective friction coefficient shows the larger ones. With rough surfaces, the spontaneous occurrence of pinning and depinning events associated with sharp wall defects notably reduces the effective static contact angle even when high aspect ratios are used. The obtained values of the effective friction coefficient show good agreement with previous literature investigations for rough and smooth lateral wall surfaces. Finally, we propose a nondimensional time to establish when contact angle effects dominate the dynamics. We found that for the materials and fluid properties used in this work, these effects become negligible for times larger than t ∼ 1 s.
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Affiliation(s)
- Pedro Manuel Garcia Eijo
- Laboratorio de Fluidodinámica, Facultad de Ingeniería, Universidad de Buenos Aires, C1063ACVBuenos Aires, Argentina
| | - Juan Martín Cabaleiro
- Laboratorio de Fluidodinámica, Facultad de Ingeniería, Universidad de Buenos Aires, C1063ACVBuenos Aires, Argentina
| | - Guillermo Artana
- Laboratorio de Fluidodinámica, Facultad de Ingeniería, Universidad de Buenos Aires, C1063ACVBuenos Aires, Argentina
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Wu F, Lin J, Wang L, Lin S. Polymer Vesicles in a Nanochannel under Flow Fields: A DPD Simulation Study. MACROMOL THEOR SIMUL 2022. [DOI: 10.1002/mats.202200027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Fangsheng Wu
- Shanghai Key Laboratory of Advanced Polymeric Materials Key Laboratory for Ultrafine Materials of Ministry of Education Frontiers Science Center for Materiobiology and Dynamic Chemistry School of Materials Science and Engineering East China University of Science and Technology Shanghai 200237 China
| | - Jiaping Lin
- Shanghai Key Laboratory of Advanced Polymeric Materials Key Laboratory for Ultrafine Materials of Ministry of Education Frontiers Science Center for Materiobiology and Dynamic Chemistry School of Materials Science and Engineering East China University of Science and Technology Shanghai 200237 China
| | - Liquan Wang
- Shanghai Key Laboratory of Advanced Polymeric Materials Key Laboratory for Ultrafine Materials of Ministry of Education Frontiers Science Center for Materiobiology and Dynamic Chemistry School of Materials Science and Engineering East China University of Science and Technology Shanghai 200237 China
| | - Shaoliang Lin
- Shanghai Key Laboratory of Advanced Polymeric Materials Key Laboratory for Ultrafine Materials of Ministry of Education Frontiers Science Center for Materiobiology and Dynamic Chemistry School of Materials Science and Engineering East China University of Science and Technology Shanghai 200237 China
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Kubochkin N, Gambaryan-Roisman T. Capillary-Driven Flow in Corner Geometries. Curr Opin Colloid Interface Sci 2022. [DOI: 10.1016/j.cocis.2022.101575] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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A H, Yang Z, Hu R, Chen YF. Roles of energy dissipation and asymmetric wettability in spontaneous imbibition dynamics in a nanochannel. J Colloid Interface Sci 2021; 607:1023-1035. [PMID: 34571292 DOI: 10.1016/j.jcis.2021.09.051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/29/2021] [Accepted: 09/09/2021] [Indexed: 01/28/2023]
Abstract
HYPOTHESIS The imbibition dynamics is controlled by energy dissipation mechanisms and influenced by asymmetric wettability in a nanochannel. We hypothesize that the imbibition dynamics can be described by a combined model of the Lucas-Washburn equation and the Cox-Voinov law considering velocity-dependent contact angles. METHODS Molecular dynamics simulations are utilized to investigate the imbibition dynamics. A wide range of wetting conditions is achieved via adjusting the liquid-solid interaction parameters, and the spontaneous imbibition processes are quantified and compared. FINDINGS The critical condition for the occurrence of spontaneous imbibition is analyzed from a surface energy perspective. The analyses of energy conversion and dissipation indicate that the viscous dissipation is dominant during spontaneous imbibition. The classical Lucas-Washburn equation is modified with the Cox-Voinov law considering the effect of the dynamic contact angle and an effective equilibrium contact angle. We show that the proposed theory well captures the imbibition dynamics embodied in the growth of imbibition length as well as the transient interface shape and velocity for both the symmetric and asymmetric wetting conditions. In nanochannels with asymmetric wettability, the imbibition length difference between the sidewalls and interface oscillations increases with wetting disparity. Our findings deepen the understanding of imbibition dynamics on the nanoscale, and provide a theoretical reference for relevant applications.
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Affiliation(s)
- Hubao A
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China; Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of the Ministry of Education, Wuhan University, Wuhan 430072, China
| | - Zhibing Yang
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China; Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of the Ministry of Education, Wuhan University, Wuhan 430072, China.
| | - Ran Hu
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China; Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of the Ministry of Education, Wuhan University, Wuhan 430072, China
| | - Yi-Feng Chen
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China; Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of the Ministry of Education, Wuhan University, Wuhan 430072, China
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Davoodabadi A, Ghasemi H. Evaporation in nano/molecular materials. Adv Colloid Interface Sci 2021; 290:102385. [PMID: 33662599 DOI: 10.1016/j.cis.2021.102385] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/17/2021] [Accepted: 02/18/2021] [Indexed: 12/29/2022]
Abstract
Evaporation is a physical phenomenon with fundamental significance to both nature and technology ranging from plant transpiration to DNA engineering. Various analytical and empirical relationships have been proposed to characterize evaporation kinetics at macroscopic scales. However, theoretical models to describe the kinetics of evaporation from nano and sub-nanometer (molecular) confinements are absent. On the other hand, the fast advancements in technology concentrated on development of nano/molecular-scale devices demand appropriate models that can accurately predict physics of phase-change in these systems. A thorough understanding of the physics of evaporation in nano/molecular materials is, thus, of critical importance to develop the required models. This understanding is also crucial to explain the intriguing evaporation-related phenomena that only take place when the characteristic length of the system drops to several nanometers. Here, we comprehensively review the underlying physics of evaporation phenomenon and discuss the effects of nano/molecular confinement on evaporation. The role of liquid-wall interface-related phenomena including the effects of disjoining pressure and flow slippage on evaporation from nano/molecular confinements are discussed. Different driving forces that can induce evaporation in small confinements, such as heat transfer, pressure drop, cavitation and density fluctuations are elaborated. Hydrophobic confinement induced evaporation and its potential application for synthetic ion channels are discussed in detail. Evaporation of water as molecular clusters rather than isolated molecules is discussed. Despite the lack of experimental investigations on evaporation at nanoscale, there exist an extensive body of literature that have applied different simulation techniques to predict the phase change behavior of liquids in nanoconfinements. We infer that exploring the effect of electrostatic interactions and flow slippage to enhance evaporation from nanoconduits is an interesting topic for future endeavors. Further future studies could be devoted to developing nano/molecular channels with evaporation-based gating mechanism and utilization of 2D materials to tune energy barrier for evaporation leading to enhanced evaporation.
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Lei W, Fong NWS, Jarvis KL, McKenzie DR. Quantifying Moisture Penetration in Encapsulated Devices by Heavy Water Mass Spectrometry: A Standard Moisture Leak Using Poly(ether-ether-ketone). ACS APPLIED MATERIALS & INTERFACES 2021; 13:13666-13675. [PMID: 33688725 DOI: 10.1021/acsami.0c23115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Moisture penetration into active biomedical implants such as the bionic ear and eye is a major problem in healthcare since surgery is required to replace devices affected by corrosion. Existing methods for measuring moisture leak rates such as the commercially available dynamic relative humidity method are not sufficiently sensitive to guarantee security against moisture penetration. Helium leak detection is highly sensitive but is challenged by the unknown relation to the moisture leak rate because of mixed flow modes involving liquid water. A standard moisture leak traceable to fundamental units is not currently available, preventing direct comparison of moisture and helium leak rates in the same device. Here, we demonstrate a practical calibrated moisture leak based on the stable polymer poly(ether-ether-ketone), for calibrating heavy water mass spectrometry. Using biomedical test structures from manufactured encapsulations, we show that in the majority of cases, calibrated measurements of molar moisture leak rates exceed the helium leak rate, especially for very small and large leaks. Comparison with theory shows that LaPlace pressure is the driving force for the enhanced moisture flows. We recommend that the compliance limit for helium testing in biomedical devices be reduced by one order of magnitude.
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Affiliation(s)
- Wenwen Lei
- National Measurement Institute, 36 Bradfield Road, West Lindfield, New South Wales 2071, Australia
| | - Nicole W S Fong
- School of Physics, University of Sydney, New South Wales 2006, Australia
| | | | - David R McKenzie
- School of Physics, University of Sydney, New South Wales 2006, Australia
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Zhang L, Wu K, Chen Z, Li J, Yu X, Hui G, Yang M. The increased viscosity effect for fracturing fluid imbibition in shale. Chem Eng Sci 2021. [DOI: 10.1016/j.ces.2020.116352] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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11
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Karna NK, Wohlert J, Lidén A, Mattsson T, Theliander H. Wettability of cellulose surfaces under the influence of an external electric field. J Colloid Interface Sci 2021; 589:347-355. [PMID: 33476890 DOI: 10.1016/j.jcis.2021.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 12/12/2020] [Accepted: 01/01/2021] [Indexed: 11/15/2022]
Abstract
HYPOTHESIS Interfacial tensions play an important role in dewatering of hydrophilic materials like nanofibrillated cellulose, and are affected by the molecular organization of water at the interface. Application of an electric field influences the orientation of water molecules along the field direction. Hence, it should be possible to alter the interfacial free energies to tune the wettability of cellulose surface through application of an external electric field thus, aiding the dewatering process. SIMULATIONS Molecular dynamics simulations of cellulose surface in contact with water under the influence of an external electric field have been conducted with GLYCAM-06 forcefield. The effect of variation in electric field intensity and directions on the spreading coefficient has been addressed via orientational preference of water molecules and interfacial free energy analyses. FINDINGS The application of electric field influences the interfacial free energy difference at the cellulose-water interface. The spreading coefficient increases with the electric field directed parallel to the cellulose-water interface while it decreases in the perpendicular electric field. Variation in interfacial free energies seems to explain the change in contact angle adequately in presence of an electric field. The wettability of cellulose surface can be tuned by the application of an external electric field.
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Affiliation(s)
- Nabin Kumar Karna
- Division of Forest Products and Chemical Engineering, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 412 96 Göteborg, Sweden; Wallenberg Wood Science Center, KTH Royal Institute of Technology, SE-10044, Sweden.
| | - Jakob Wohlert
- Wallenberg Wood Science Center, KTH Royal Institute of Technology, SE-10044, Sweden; Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, SE-10044, Sweden.
| | - Anna Lidén
- Division of Forest Products and Chemical Engineering, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 412 96 Göteborg, Sweden.
| | - Tuve Mattsson
- Division of Forest Products and Chemical Engineering, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 412 96 Göteborg, Sweden; Wallenberg Wood Science Center, KTH Royal Institute of Technology, SE-10044, Sweden.
| | - Hans Theliander
- Division of Forest Products and Chemical Engineering, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 412 96 Göteborg, Sweden; Wallenberg Wood Science Center, KTH Royal Institute of Technology, SE-10044, Sweden.
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Badizad MH, Koleini MM, Greenwell HC, Ayatollahi S, Ghazanfari MH. A Deep Look into the Dynamics of Saltwater Imbibition in a Calcite Nanochannel: Temperature Impacts Capillarity Regimes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:9035-9046. [PMID: 32551693 DOI: 10.1021/acs.langmuir.0c00437] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This research concerns fundamentals of spontaneous transport of saltwater (1 mol·dm-3 NaCl solution) in nanopores of calcium carbonates. A fully atomistic model was adopted to scrutinize the temperature dependence of flow regimes during solution transport under CaCO3 nanoconfinement. The early time of capillary filling is inertia-dominated, and the solution penetrates with a near-planar meniscus at constant velocity. Following a transition period, the meniscus angle falls to a stabilized value, characterizing the capillary-viscous advancement in the calcite channel. At this stage, brine displacement follows a parabolic relationship consistent with the classical Lucas-Washburn (LW) theory. Approaching the slit outlet, the meniscus contact lines spread widely on the solid substrate and brine leaves the channel at a constant rate, in oppose to the LW law. The brine imbibition rate considerably increases at higher temperatures as a result of lower viscosity and greater tendency to form wetting layers on slit walls. We also pointed out a longer primary inertial regime and delayed onset of the viscous-capillary regime at higher temperatures. Throughout the whole span of capillary displacement, transport of sodium and chloride ions is tied to dynamics and diffusion of the water phase, even at the mineral interface. The results presented in this study are of broad implications in diverse science and technological applications.
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Affiliation(s)
- Mohammad Hasan Badizad
- Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran 11365-11155, Iran
| | - Mohammad Mehdi Koleini
- Sharif Upstream Petroleum Research Institute (SUPRI), Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran 11365-9465, Iran
| | | | - Shahab Ayatollahi
- Sharif Upstream Petroleum Research Institute (SUPRI), Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran 11365-9465, Iran
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Nazari M, Davoodabadi A, Huang D, Luo T, Ghasemi H. On interfacial viscosity in nanochannels. NANOSCALE 2020; 12:14626-14635. [PMID: 32614001 DOI: 10.1039/d0nr02294b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Capillary driven transport of liquids in nanoscopic channels is an omnipresent phenomenon in nature and technology including fluid flow in the human body and plants, drug delivery, nanofluidic devices, and energy/water systems. However, the kinetics of this mass transport mechanism remains in question as the well-known Lucas-Washburn (LW) model predicts significantly faster flow rates compared to the experimental observations. We here showed the role of interfacial viscosity in capillary motion slowdown in nanochannels through a combination of experimental, analytical and molecular dynamics techniques. We showed that the slower liquid flow is due to the formation of a thin liquid layer adjacent to the channel walls with a viscosity substantially greater than the bulk liquid. By incorporating the effect of the interfacial layer, we presented a theoretical model that accurately predicts the capillarity kinetics in nanochannels of different heights. Non-equilibrium molecular dynamics simulation confirmed the obtained interfacial viscosities. The viscosities of isopropanol and ethanol within the interfacial layer were 9.048 mPa s and 4.405 mPa s, respectively (i.e. 279% and 276% greater than their bulk values). We also showed that the interfacial layers are 6.4 nm- and 5.3 nm-thick for isopropanol and ethanol, respectively.
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Affiliation(s)
- Masoumeh Nazari
- Department of Mechanical Engineering, University of Houston, 4726 Calhoun Rd, Houston, Texas 77204, USA.
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Abstract
Nanoconfined fluids (NCFs), which are confined in nanospaces, exhibit distinctive nanoscale effects, including surface effects, small-size effects, quantum effects, and others. The continuous medium hypothesis in fluid mechanics is not valid in this context because of the comparable characteristic length of spaces and molecular mean free path, and accordingly, the classical continuum theories developed for the bulk fluids usually cannot describe the mass and energy transport of NCFs. In this Perspective, we summarize the nanoscale effects on the thermodynamics, mass transport, flow dynamics, heat transfer, phase change, and energy transport of NCFs and highlight the related representative works. The applications of NCFs in the fields of membrane separation, oil and gas production, energy harvesting and storage, and biological engineering are especially indicated. Currently, the theoretical description framework of NCFs is still missing, and it is expected that this framework can be established by adopting the classical continuum theories with the consideration of nanoscale effects.
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Affiliation(s)
- Chengzhen Sun
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Shaanxi 710049, China
| | - Runfeng Zhou
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Shaanxi 710049, China
| | - Zhixiang Zhao
- School of Urban Planning and Municipal Engineering, Xi'an Polytechnic University, Shaanxi 710048, China
| | - Bofeng Bai
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Shaanxi 710049, China
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15
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Willmott GR, Briole A, Szczepaniak F. Inertial capillary uptake of drops. Phys Rev E 2020; 101:043109. [PMID: 32422711 DOI: 10.1103/physreve.101.043109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 03/25/2020] [Indexed: 11/07/2022]
Abstract
Uptake of liquid drops into capillary tubes has been experimentally studied and quantitatively analyzed. In experiments, drops of water and aqueous glycerol (≤50 wt %) were drawn into cylindrical borosilicate glass and quartz tubes with an inner diameter of 0.50-0.75 mm. The meniscus height rise was measured using high-speed images captured at 4000 frames per second, and results within a conservatively defined inertial regime indicate constant uptake velocity. An increase in the inertial velocity with drop curvature was observed due to increasing Laplace pressure in the drop, as drop sizes were comparable to the width of the capillary tubes. Measured velocities were slower than predicted by a purely inertial-capillary model and best described by introducing a contact line friction, consistent with the observed variability and viscosity dependence of the results. Mean friction coefficients in borosilicate capillaries ranged from 169±1 for 50 wt % glycerol drops to 218±1 for water drops. Peaks in the instantaneous Laplace pressure caused by surface oscillations were also measured. Correlations with uptake velocity were qualitatively apparent, with a delay between peaks of similar magnitude to the inertial-capillary oscillation time.
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Affiliation(s)
- Geoff R Willmott
- Department of Physics and School of Chemical Sciences, The University of Auckland, Auckland, New Zealand, and The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand
| | - Alice Briole
- Départements Physique et Chimie, École normale supérieure de Lyon, 69342 Lyon, France
| | - Florence Szczepaniak
- Départements Physique et Chimie, École normale supérieure de Lyon, 69342 Lyon, France
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Huang P, Shen L, Gan Y, Maggi F, El-Zein A, Pan Z. Atomistic Study of Dynamic Contact Angles in CO 2-Water-Silica System. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5324-5332. [PMID: 30869902 DOI: 10.1021/acs.langmuir.9b00076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The dynamic wetting for the CO2-water-silica system occurring in deep reservoirs is complex because of the interactions among multiple phases. This work aims to quantify the contact angle of CO2-water flow in the silica channel at six different flow velocities using molecular dynamics. The dynamic contact angle values at different contact line velocities are obtained for the CO2-water-silica system. By calculating the rates of the adsorption-desorption process of CO2 and water molecules on the silica surface using molecular dynamics simulations, it has been found that the results of the dynamic contact angle can be explained by the molecular kinetic theory and predicted from the equilibrium molecular simulations. Moreover, the capillary pressure at different contact line velocities is predicted according to the Young-Laplace equation. The change in contact angles at different velocities is compared with empirical equations in terms of capillary number. The results of this study can help us better understand the dynamic process of the multiphase flow at the nanoscale under realistic reservoir conditions.
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Affiliation(s)
- Pengyu Huang
- School of Civil Engineering , Building J05 , The University of Sydney , Sydney , NSW 2006 , Australia
| | - Luming Shen
- School of Civil Engineering , Building J05 , The University of Sydney , Sydney , NSW 2006 , Australia
| | - Yixiang Gan
- School of Civil Engineering , Building J05 , The University of Sydney , Sydney , NSW 2006 , Australia
| | - Federico Maggi
- School of Civil Engineering , Building J05 , The University of Sydney , Sydney , NSW 2006 , Australia
| | - Abbas El-Zein
- School of Civil Engineering , Building J05 , The University of Sydney , Sydney , NSW 2006 , Australia
| | - Zhejun Pan
- CSIRO Energy , Private Bag 10 , Clayton South , VIC 3169 , Australia
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17
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Feng D, Li X, Wang X, Li J, Zhang T, Sun Z, He M, Liu Q, Qin J, Han S, Hu J. Anomalous Capillary Rise under Nanoconfinement: A View of Molecular Kinetic Theory. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:7714-7725. [PMID: 29889541 DOI: 10.1021/acs.langmuir.8b01397] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Understanding the capillary filling behaviors in nanopores is crucial for many science and engineering problems. Compared with the classical Bell-Cameron-Lucas-Washburn (BCLW) theory, anomalous coefficient is always observed because of the increasing role of surfaces. Here, a molecular kinetics approach is adopted to explain the mechanism of anomalous behaviors at the molecular level; a unified model taking account of the confined liquid properties (viscosity and density) and slip boundary condition is proposed to demonstrate the macroscopic consequences, and the model results are successfully validated against the published literature. The results show that (1) the effective viscosity induced by the interaction from the pore wall, as a function of wettability and the pore dimension (nanoslit height or nanotube diameter), may remarkably slow down the capillary filling process more than theoretically predicted. (2) The true slip, where water molecules directly slide on the walls, strongly depends on the wettability and will increase as the contact angle increases. In the hydrophilic nanopores, though, the magnitude may be comparable with the pore dimensions and promote the capillary filling compared with the classical BCLW model. (3) Compared with the other model, the proposed model can successfully predict the capillary filling for both faster or slower capillary filling process; meanwhile, it can capture the underlying physics behind these behaviors at the molecular level based on the effective viscosity and slippage. (4) The surface effects have different influence on the capillary filling in nanoslits and nanotubes, and the relative magnitude will change with the variation of wettability as well as the pore dimension.
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Affiliation(s)
- Dong Feng
- State Key Laboratory of Petroleum Resources and Engineering in China , University of Petroleum at Beijing , Beijing 102249 , P. R. China
- MOE Key Laboratory of Petroleum Engineering , China University of Petroleum (Beijing) , Beijing 102249 , P. R. China
| | - Xiangfang Li
- State Key Laboratory of Petroleum Resources and Engineering in China , University of Petroleum at Beijing , Beijing 102249 , P. R. China
- MOE Key Laboratory of Petroleum Engineering , China University of Petroleum (Beijing) , Beijing 102249 , P. R. China
| | - Xiangzeng Wang
- Shaanxi Yanchang Petroleum (Group) Corp. Ltd. , Xi'an 710075 , P. R. China
| | - Jing Li
- State Key Laboratory of Petroleum Resources and Engineering in China , University of Petroleum at Beijing , Beijing 102249 , P. R. China
- Chemical and Petroleum Engineering , University of Calgary , Calgary , Alberta T2N1N4 , Canada
| | - Tao Zhang
- State Key Laboratory of Petroleum Resources and Engineering in China , University of Petroleum at Beijing , Beijing 102249 , P. R. China
| | - Zheng Sun
- State Key Laboratory of Petroleum Resources and Engineering in China , University of Petroleum at Beijing , Beijing 102249 , P. R. China
| | - Minxia He
- State Key Laboratory of Petroleum Resources and Engineering in China , University of Petroleum at Beijing , Beijing 102249 , P. R. China
| | - Qing Liu
- State Key Laboratory of Petroleum Resources and Engineering in China , University of Petroleum at Beijing , Beijing 102249 , P. R. China
| | - Jiazheng Qin
- State Key Laboratory of Petroleum Resources and Engineering in China , University of Petroleum at Beijing , Beijing 102249 , P. R. China
| | - Song Han
- State Key Laboratory of Petroleum Resources and Engineering in China , University of Petroleum at Beijing , Beijing 102249 , P. R. China
| | - Jinchuan Hu
- State Key Laboratory of Petroleum Resources and Engineering in China , University of Petroleum at Beijing , Beijing 102249 , P. R. China
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18
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Fang C, Zhang F, Qiao R. Invasion of gas into mica nanopores: a molecular dynamics study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:224001. [PMID: 29664007 DOI: 10.1088/1361-648x/aabead] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The invasion of gas into liquid-filled nanopores is encountered in many engineering problems but is not yet well understood. We report molecular dynamics simulations of the invasion of methane gas into water-filled mica pores with widths of 2-6 nm. Gas invades into a pore only when the pressure exceeds a breakthrough pressure and a thin residual water film is left on the mica wall as the gas phase moves deeper into the pore. The gas breakthrough pressure of pores as narrow as 2 nm can be modeled reasonably well by the capillary pressure if the finite thickness of residual liquid water film and the liquid-gas interface are taken into account. The movement of the front of the liquid meniscus during gas invasion can be quantitatively described using the classical hydrodynamics when the negative slip length on the strongly hydrophilic mica walls is taken into account. Understanding the molecular mechanisms underlying the gas invasion in the system studied here will form the foundation for quantitative prediction of gas invasion in practical porous media.
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Affiliation(s)
- Chao Fang
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061, United States of America
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19
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Ebrahimi F, Ramazani F, Sahimi M. Nanojunction Effects on Water Flow in Carbon Nanotubes. Sci Rep 2018; 8:7752. [PMID: 29773862 PMCID: PMC5958144 DOI: 10.1038/s41598-018-26072-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 05/03/2018] [Indexed: 11/15/2022] Open
Abstract
We report on the results of extensive molecular dynamics simulation of water imbibition in carbon nanotubes (CNTs), connected together by converging or diverging nanojunctions in various configurations. The goal of the study is to understand the effect of the nanojunctions on the interface motion, as well as the differences between what we study and water imbibition in microchannels. While the dynamics of water uptake in the entrance CNT is the same as that of imbibition in straight CNTs, with the main source of energy dissipation being the friction at the entrance, water uptake in the exit CNT is more complex due to significant energy loss in the nanojunctions. We derive an approximate but accurate expression for the pressure drop in the nanojunction. A remarkable difference between dynamic wetting of nano- and microjunctions is that, whereas water absorption time in the latter depends only on the ratios of the radii and of the lengths of the channels, the same is not true about the former, which is shown to be strongly dependent upon the size of each segment of the nanojunction. Interface pinning-depinning also occurs at the convex edges.
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Affiliation(s)
- Fatemeh Ebrahimi
- Physics Department, University of Birjand, Birjand, 97175-615, Iran
| | | | - Muhammad Sahimi
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California, 90089-1211, USA.
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20
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Wang X, Zhang Z, Torsæter O, He J. Atomistic insights into the nanofluid transport through an ultra-confined capillary. Phys Chem Chem Phys 2018; 20:4831-4839. [PMID: 29383352 DOI: 10.1039/c7cp08140e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nanofluid or nanoparticle (NP) transport in confined channels is of great importance for many biological and industrial processes. In this study, molecular dynamics simulation has been employed to investigate the spontaneous two-phase displacement process in an ultra-confined capillary controlled by the surface wettability of NPs. The results clearly show that the presence of NPs modulates the fluid-fluid meniscus and hinders the displacement process compared with the NP-free case. From the perspective of motion behavior, hydrophilic NPs disperse in the water phase or adsorb on the capillary, while hydrophobic and mixed-wet NPs are mainly distributed in the fluid phase. The NPs dispersed into fluids tend to increase the viscosity of the fluids, while the adsorbed NPs contribute to the wettability alteration of the solid capillary. Via capillary number calculations, it is uncovered that the viscosity increase of fluids is responsible for the hindered spontaneous displacement process by hydrophobic and mixed NPs. The wettability alteration of the capillary induced by adsorbed NPs dominates the enhanced displacement in the case of hydrophilic NPs. Our findings provide guidance for modifying the rate of capillary filling and reveal the microscopic mechanism transporting NPs into porous media, which is significant to the design of NPs for target applications.
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Affiliation(s)
- Xiao Wang
- NTNU Nanomechanical Lab, Department of Structural Engineering, Faculty of Engineering, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway.
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21
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Karna NK, Rojano Crisson A, Wagemann E, Walther JH, Zambrano HA. Effect of an external electric field on capillary filling of water in hydrophilic silica nanochannels. Phys Chem Chem Phys 2018; 20:18262-18270. [DOI: 10.1039/c8cp03186j] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Development of functional nanofluidic devices requires understanding the fundamentals of capillary driven flow in nanochannels.
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Affiliation(s)
- Nabin Kumar Karna
- Department of Chemical Engineering, Universidad de Concepcion
- Concepcion
- Chile
- Technology Development Unit
- Coronel
| | | | - Enrique Wagemann
- Department of Chemical Engineering, Universidad de Concepcion
- Concepcion
- Chile
| | - Jens H. Walther
- Technical University of Denmark
- Copenhagen
- Denmark
- Chair of Computational Science
- ETH Zurich
| | - Harvey A. Zambrano
- Department of Mechanical Engineering, Universidad Tecnica Federico Santa Maria
- Valparaiso
- Chile
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22
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Shen D, Chen D, Yang Z, Liu H, Chen T, Sun L, Fukuda T. Electron Beam Irradiation Induced Multiwalled Carbon Nanotubes Fusion inside SEM. SCANNING 2017; 2017:8563931. [PMID: 29201267 PMCID: PMC5672700 DOI: 10.1155/2017/8563931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 08/09/2017] [Accepted: 08/30/2017] [Indexed: 06/07/2023]
Abstract
This paper reported a method of multiwalled carbon nanotubes (MWCNTs) fusion inside a scanning electron microscope (SEM). A CNT was picked up by nanorobotics manipulator system which was constructed in SEM with 21 DOFs and 1 nm resolution. The CNT was picked up and placed on two manipulators. The tensile force was 140 nN when the CNT was pulled into two parts. Then, two parts of the CNT were connected to each other by two manipulators. The adhered force between two parts was measured to be about 20 nN. When the two parts of CNT were connected again, the contact area was fused by focused electron beam irradiation for 3 minutes. The tensile force of the junction was measured to be about 100 nN. However, after fusion, the tensile force was five times larger than the tensile force connected only by van der Waals force. This force was 70 percent of the tensile force before pulling out of CNTs. The results revealed that the electron beam irradiation was a promising method for CNT fusion. We hope this technology will be applied to nanoelectronics in the near future.
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Affiliation(s)
- Daming Shen
- Robotics and Microsystem Center, Soochow University, Suzhou 215006, China
- School of Mechatronics Engineering, Harbin University of Science and Technology, Harbin 150080, China
| | - Donglei Chen
- Robotics and Microsystem Center, Soochow University, Suzhou 215006, China
| | - Zhan Yang
- Robotics and Microsystem Center, Soochow University, Suzhou 215006, China
| | - Huicong Liu
- Robotics and Microsystem Center, Soochow University, Suzhou 215006, China
| | - Tao Chen
- Robotics and Microsystem Center, Soochow University, Suzhou 215006, China
| | - Lining Sun
- Robotics and Microsystem Center, Soochow University, Suzhou 215006, China
| | - Toshio Fukuda
- Department of Micro-Nano Systems Engineering, Nagoya University, Nagoya 464-0814, Japan
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23
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Li H, Zhong J, Pang Y, Zandavi SH, Persad AH, Xu Y, Mostowfi F, Sinton D. Direct visualization of fluid dynamics in sub-10 nm nanochannels. NANOSCALE 2017; 9:9556-9561. [PMID: 28664968 DOI: 10.1039/c7nr02176c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Optical microscopy is the most direct method to probe fluid dynamics at small scales. However, contrast between fluid phases vanishes at ∼10 nm lengthscales, limiting direct optical interrogation to larger systems. Here, we present a method for direct, high-contrast and label-free visualization of fluid dynamics in sub-10 nm channels, and apply this method to study capillary filling dynamics at this scale. The direct visualization of confined fluid dynamics in 8-nm high channels is achieved with a conventional bright-field optical microscope by inserting a layer of a high-refractive-index material, silicon nitride (Si3N4), between the substrate and the nanochannel, and the height of which is accurately controlled down to a few nanometers by a SiO2 spacer layer. The Si3N4 layer exhibits a strong Fabry-Perot resonance in reflection, providing a sharp contrast between ultrathin liquid and gas phases. In addition, the Si3N4 layer enables robust anodic bonding without nanochannel collapse. With this method, we demonstrate the validity of the classical Lucas-Washburn equation for capillary filling in the sub-10 nm regime, in contrast to the previous studies, for both polar and nonpolar liquids, and for aqueous salt solutions.
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Affiliation(s)
- Huawei Li
- Key Laboratory of Precision Microelectronic Manufacturing Technology & Equipment of Ministry of Education, Guangdong University of Technology, Guangzhou, 510006, China
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24
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Effect of Nanoparticles on Spontaneous Imbibition of Water into Ultraconfined Reservoir Capillary by Molecular Dynamics Simulation. ENERGIES 2017. [DOI: 10.3390/en10040506] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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25
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Fang C, Qiao R. Surface hydration drives rapid water imbibition into strongly hydrophilic nanopores. Phys Chem Chem Phys 2017; 19:20506-20512. [DOI: 10.1039/c7cp02115a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Surface hydration-driven imbibition of water into strongly hydrophilic pores follows a diffusive scaling law and exhibits effective diffusion coefficients much higher than water molecules.
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Affiliation(s)
- Chao Fang
- Department of Mechanical Engineering
- Virginia Tech
- Blacksburg
- USA
| | - Rui Qiao
- Department of Mechanical Engineering
- Virginia Tech
- Blacksburg
- USA
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26
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Wang Y, Sinha S, Hu L, Das S. Interaction between a water drop and holey graphene: retarded imbibition and generation of novel water–graphene wetting states. Phys Chem Chem Phys 2017; 19:27421-27434. [DOI: 10.1039/c7cp04411a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Water nanodrop imbibition in holey graphene is studied unraveling novel fiber-like wetting state that enhances water–accessible graphene surface area.
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Affiliation(s)
- Yanbin Wang
- Department of Mechanical Engineering
- University of Maryland
- College Park
- USA
| | - Shayandev Sinha
- Department of Mechanical Engineering
- University of Maryland
- College Park
- USA
| | - Liangbing Hu
- Deapartment of Materials Science and Engineering
- University of Maryland
- College Park
- USA
| | - Siddhartha Das
- Department of Mechanical Engineering
- University of Maryland
- College Park
- USA
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27
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Wagemann E, Oyarzua E, Walther JH, Zambrano HA. Slip divergence of water flow in graphene nanochannels: the role of chirality. Phys Chem Chem Phys 2017; 19:8646-8652. [DOI: 10.1039/c6cp07755b] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Graphene has attracted considerable attention due to its characteristics as a 2D material and its fascinating properties, providing a potential building block for fabrication of nanofluidic conduits.
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Affiliation(s)
| | | | - Jens H. Walther
- Technical University of Denmark
- Copenhagen
- Denmark
- Chair of Computational Science
- ETH Zurich
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28
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Lei W, McKenzie DR. Nanoscale Capillary Flows in Alumina: Testing the Limits of Classical Theory. J Phys Chem Lett 2016; 7:2647-2652. [PMID: 27336652 DOI: 10.1021/acs.jpclett.6b01021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Anodic aluminum oxide (AAO) membranes have well-formed cylindrical channels, as small as 10 nm in diameter, in a close packed hexagonal array. The channels in AAO membranes simulate very small leaks that may be present for example in an aluminum oxide device encapsulation. The 10 nm alumina channel is the smallest that has been studied to date for its moisture flow properties and provides a stringent test of classical capillary theory. We measure the rate at which moisture penetrates channels with diameters in the range of 10 to 120 nm with moist air present at 1 atm on one side and dry air at the same total pressure on the other. We extend classical theory for water leak rates at high humidities by allowing for variable meniscus curvature at the entrance and show that the extended theory explains why the flow increases greatly when capillary filling occurs and enables the contact angle to be determined. At low humidities our measurements for air-filled channels agree well with theory for the interdiffusive flow of water vapor in air. The flow rate of water-filled channels is one order of magnitude less than expected from classical capillary filling theory and is coincidentally equal to the helium flow rate, validating the use of helium leak testing for evaluating moisture flows in aluminum oxide leaks.
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Affiliation(s)
- Wenwen Lei
- School of Physics, University of Sydney , Sydney, NSW 2006, Australia
| | - David R McKenzie
- School of Physics, University of Sydney , Sydney, NSW 2006, Australia
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29
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Zambrano HA, Vásquez N, Wagemann E. Wall embedded electrodes to modify electroosmotic flow in silica nanoslits. Phys Chem Chem Phys 2016; 18:1202-11. [PMID: 26658698 DOI: 10.1039/c5cp05785j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Electroosmotic flow in a silica slit channel with nonuniform surface charge density is investigated. In nanoconfinement, the electrical double layer occupies a non-negligible fraction of the system. Therefore, modifying the charge density on specific locations on the channel wall surface allows effective manipulation of the electroosmotic flow rates. In the present study, extensive (160 ns) nonequilibrium molecular dynamics simulations are conducted to investigate the ability of controlling the electroosmotic flow control in a nanoslit by patterning the surface potential. The mechanism to modify the surface charge consists of a set of charged electrodes embedded within one of the channel walls. The presence of the embedded electrodes results in the redistribution of ions in the electrolyte solution and in the alteration of the electroosmotic flow throughout the nanochannel. Indeed, the results reveal significant changes in the electroosmotic driving force and velocity profiles including local flow reversal. This study provides physical insight into the direct manipulation of the electrokinetic flow in nanoslits.
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Affiliation(s)
- Harvey A Zambrano
- Department of Chemical Engineering, Universidad de Concepcion, Concepcion, Chile.
| | - Nicolás Vásquez
- Department of Chemical Engineering, Universidad de Concepcion, Concepcion, Chile.
| | - Enrique Wagemann
- Department of Chemical Engineering, Universidad de Concepcion, Concepcion, Chile.
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30
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Capillary rise dynamics of liquid hydrocarbons in mesoporous silica as explored by gravimetry, optical and neutron imaging: Nano-rheology and determination of pore size distributions from the shape of imbibition fronts. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2015.09.055] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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31
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Gravelle S, Ybert C, Bocquet L, Joly L. Anomalous capillary filling and wettability reversal in nanochannels. Phys Rev E 2016; 93:033123. [PMID: 27078463 DOI: 10.1103/physreve.93.033123] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Indexed: 11/07/2022]
Abstract
This work revisits capillary filling dynamics in the regime of nanometric to subnanometric channels. Using molecular dynamics simulations of water in carbon nanotubes, we show that for tube radii below one nanometer, both the filling velocity and the Jurin rise vary nonmonotonically with the tube radius. Strikingly, with fixed chemical surface properties, this leads to confinement-induced reversal of the tube wettability from hydrophilic to hydrophobic for specific values of the radius. By comparing with a model liquid metal, we show that these effects are not specific to water. Using complementary data from slit channels, we then show that they can be described using the disjoining pressure associated with the liquid structuring in confinement. This breakdown of the standard continuum framework is of main importance in the context of capillary effects in nanoporous media, with potential interests ranging from membrane selectivity to mechanical energy storage.
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Affiliation(s)
- Simon Gravelle
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon 69622 Villeurbanne, France
| | - Christophe Ybert
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon 69622 Villeurbanne, France
| | - Lydéric Bocquet
- LPS, UMR CNRS 8550, Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris, France
| | - Laurent Joly
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon 69622 Villeurbanne, France
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32
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Karna NK, Oyarzua E, Walther JH, Zambrano HA. Effect of the meniscus contact angle during early regimes of spontaneous imbibition in nanochannels. Phys Chem Chem Phys 2016; 18:31997-32001. [DOI: 10.1039/c6cp06155a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Time evolution of the capillary front and meniscus contact angle during the capillary filling of silica nanochannels.
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Affiliation(s)
- Nabin Kumar Karna
- Universidad de Concepcion
- Concepcion
- Chile
- Unidad de Desarrollo Tecnologico
- Coronel
| | | | - Jens H. Walther
- Technical University of Denmark
- Copenhagen
- Denmark
- Chair of Computational Science
- ETH Zurich
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