1
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Kim H, Lee KK, Firisa G, Lee J, Choi MC, Kim YJ. Fractionation by Spatially Heterogeneous Diffusion: Experiments and the Two-Component Random Walk Model. J Am Chem Soc 2024. [PMID: 39214616 DOI: 10.1021/jacs.4c05902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
The fundamental question regarding the fractionation phenomenon is whether diffusion alone is responsible for it or whether an additional advection dynamic is involved. We studied the fractionation by diffusion of particles in spatially heterogeneous environments. By experimentally observing the time-sequential fractionation patterns of dye particles diffusing across a solid-solid interface of varying polyacrylamide gel densities, we found that the two-component diffusion model accurately captures the observed fractionation dynamics. In contrast, single-component diffusion models by Fick, Wereide, and Chapman do not. Our results indicate that diffusion alone can explain the fractionation phenomenon and that additional advection dynamics are not involved. The underlying physics in the fractionation phenomenon is discussed by using a two-component random walk model.
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Affiliation(s)
- Hoyoun Kim
- Department of Mathematical Science, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
- Computer, Electrical and Mathematical Sciences and Engineering Division (CEMSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Kingdom of Saudi Arabia
| | - KeunMin Ken Lee
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Gadisa Firisa
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Juncheol Lee
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Myung Chul Choi
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Yong-Jung Kim
- Department of Mathematical Science, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
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2
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Becerra D, Walther JH, Zambrano HA. Role of Underlying Substrates on the Interfacial Thermal Transport in Supported Graphene Nanochannels: Implications of Thermal Translucency. NANO LETTERS 2024. [PMID: 39167431 DOI: 10.1021/acs.nanolett.4c02106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/23/2024]
Abstract
We study the role of underlying substrates on interfacial heat transfer within supported graphene nanochannels. Due to graphene's translucency, the underlying substrate, apart from its known hydrodynamic impact on fluid flow, also influences heat transport. We introduce the term "thermal translucency" to describe this phenomenon in the context of interfacial heat transfer. Our findings reveal that the Kapitza resistance, RK, is dependent on the specific underlying substrate. The specific underlying substrate alters the water-graphene interface potential landscape due to graphene's translucency, leading to a breakdown in the inverse relationship between interfacial water density peaks and RK values, typically observed at water-graphene and water-graphite interfaces. Remarkably, higher interfacial water density peaks correlate with more ordered energy patterns, not necessarily tied to more hydrophilic substrates as the literature commonly suggests for lower RK values. The insights provided have implications for controlling and tuning thermal transport and heat storage in nanofluidic devices.
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Affiliation(s)
- Diego Becerra
- Department of Chemical Engineering, Universidad de Concepción, Concepción 4030000, Chile
| | - Jens H Walther
- Department of Civil and Mechanical Engineering, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Harvey A Zambrano
- Department of Mechanical Engineering, Universidad Técnica Federico Santa María, Valparaíso 2340000, Chile
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3
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Chen Y, Zhu F, Leng J, Ying T, Jiang JW, Zhou Q, Chang T, Guo W, Gao H. Fluctuotaxis: Nanoscale directional motion away from regions of fluctuation. Proc Natl Acad Sci U S A 2023; 120:e2220500120. [PMID: 37487105 PMCID: PMC10401016 DOI: 10.1073/pnas.2220500120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 06/27/2023] [Indexed: 07/26/2023] Open
Abstract
Regulating the motion of nanoscale objects on a solid surface is vital for a broad range of technologies such as nanotechnology, biotechnology, and mechanotechnology. In spite of impressive advances achieved in the field, there is still a lack of a robust mechanism which can operate under a wide range of situations and in a controllable manner. Here, we report a mechanism capable of controllably driving directed motion of any nanoobjects (e.g., nanoparticles, biomolecules, etc.) in both solid and liquid forms. We show via molecular dynamics simulations that a nanoobject would move preferentially away from the fluctuating region of an underlying substrate, a phenomenon termed fluctuotaxis-for which the driving force originates from the difference in atomic fluctuations of the substrate behind and ahead of the object. In particular, we find that the driving force can depend quadratically on both the amplitude and frequency of the substrate and can thus be tuned flexibly. The proposed driving mechanism provides a robust and controllable way for nanoscale mass delivery and has potential in various applications including nanomotors, molecular machines, etc.
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Affiliation(s)
- Yang Chen
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Frontier Science Center of Mechanoinformatics, School of Mechanics and Engineering Science, Shanghai University, Shanghai200072, China
| | - Fangyan Zhu
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Frontier Science Center of Mechanoinformatics, School of Mechanics and Engineering Science, Shanghai University, Shanghai200072, China
| | - Jiantao Leng
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Frontier Science Center of Mechanoinformatics, School of Mechanics and Engineering Science, Shanghai University, Shanghai200072, China
| | - Tianquan Ying
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Frontier Science Center of Mechanoinformatics, School of Mechanics and Engineering Science, Shanghai University, Shanghai200072, China
| | - Jin-Wu Jiang
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Frontier Science Center of Mechanoinformatics, School of Mechanics and Engineering Science, Shanghai University, Shanghai200072, China
- Joint-Research Center for Computational Materials, Zhejiang Laboratory, Hangzhou311100, China
| | - Quan Zhou
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Frontier Science Center of Mechanoinformatics, School of Mechanics and Engineering Science, Shanghai University, Shanghai200072, China
| | - Tienchong Chang
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Frontier Science Center of Mechanoinformatics, School of Mechanics and Engineering Science, Shanghai University, Shanghai200072, China
- Joint-Research Center for Computational Materials, Zhejiang Laboratory, Hangzhou311100, China
- Shanghai Institute of Aircraft Mechanics and Control, Tongji University, Shanghai200092, China
| | - Wanlin Guo
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, Institute of Nanoscience of Nanjing University of Aeronautics and Astronautics, Nanjing210016, China
| | - Huajian Gao
- School of Mechanical and Aerospace Engineering, College of Engineering, Nanyang Technological University, Singapore639798, Singapore
- Institute of High Performance Computing, Agency for Science, Technology and Research, Singapore138632, Singapore
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4
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Wang Z. Trapping Molecules in a Covalent Graphene-Nanotube Hybrid. J Phys Chem B 2023. [PMID: 37378591 DOI: 10.1021/acs.jpcb.3c03132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
This study employs molecular dynamics simulations to examine the physisorption behavior of hydrocarbon molecules on a covalent graphene-nanotube hybrid nanostructure. The results indicate that the adsorbed molecules undergo self-diffusion into the nanotubes without the need for external driving forces, primarily driven by significant variations in the binding energy throughout different regions. Notably, these molecules remain securely trapped within the tubes even at room temperature, thanks to a "gate" effect observed at the neck region, despite the presence of a concentration gradient that would typically hinder such trapping. This mechanism of passive mass transport and retention holds implications for the storage and separation of gas molecules.
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Affiliation(s)
- Zhao Wang
- Department of Physics, Guangxi University, 530004 Nanning, China
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5
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Oyarzua E, Walther JH, Zambrano HA. Water flow in graphene nanochannels driven by imposed thermal gradients: the role of flexural phonons. Phys Chem Chem Phys 2023; 25:5073-5081. [PMID: 36722986 DOI: 10.1039/d2cp04093j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Accurate control of fluid transport in nanoscale structures is key to enable the design of foreseeable nanofluidic devices with applications in many fields such as chip cooling, energy conversion, drug delivery and medical diagnosis. Here, inspired by the experimental observation of intrinsic thermal ripples in graphene and by recent advances in the manipulation of 2D nanomaterials, we introduce a graphene-based thermal nanopump which produces controlled and continuous liquid flow in nanoslit channels. We investigate the performance of this thermal nanopump employing large scale molecular dynamics simulations. Upon systematically imposing thermal gradients, a net water flow towards the low-temperature zone is observed, achieving flow velocities up to 4 m s-1. We observe that water flow rates increase monotonically due to larger ripple fluctuations on the graphene layers as higher thermal gradients are applied. Moreover, we find that the out-of-plane flexural phonons in graphene are responsible for flow generation wherein lower frequency phonon branches are activated with higher imposed thermal gradients. Furthermore, by modifying the wettability of the channel walls, an increase of 50% in the water flow rates is observed, showing that the efficiency of the proposed thermal pump can be enhanced by tuning the channel wall hydrophobicity. Our results indicate that thermal gradients can be employed to drive continuous water flow in graphene nanoslit channels with potential applications in nanofluidic devices.
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Affiliation(s)
- Elton Oyarzua
- Department of Computing Technologies, Swinburne University of Technology, P.O. Box 218 Hawthorn, Victoria 3122, Australia
| | - Jens H Walther
- Department of Civil and Mechanical Engineering, Technical University of Denmark, DK-2800 Kgs, Lyngby, Denmark
| | - Harvey A Zambrano
- Department of Mechanical Engineering, Universidad Técnica Federico Santa María, Valparaiso, Chile.
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6
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Egoshi T, Uemura N, Kizuka T. Solid state molybdenum carbide nanomotors driven via high temperature carbon-decomposition catalytic reactions. RSC Adv 2022; 12:13203-13208. [PMID: 35520127 PMCID: PMC9063943 DOI: 10.1039/d2ra01846b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 04/22/2022] [Indexed: 11/21/2022] Open
Abstract
The motion of solid state nanomotors, i.e., molybdenum carbide nanoparticles, which were driven via carbon-decomposition catalytic reactions at ∼2900 K, was directly observed by in situ transmission electron microscopy. The nanomotors exhibited unidirectional linear motions inside the hollow space of multiwall carbon nanotubes, reciprocating motions around the nanotube endcaps, and rotational motions in the hollow spaces of carbon nanocapsules. The inner atomic wall-layers of carbon nanotubes and nanocapsules were consumed during the nanomotor motions. Time series of TEM images observed in the motion of a MoC nanomotor encapsulated in a carbon nanotube during in situ laser irradiation.![]()
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Affiliation(s)
- Tomoya Egoshi
- Department of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba 1-1-1, Tennoudai Tsukuba Ibaraki 305-8573 Japan
| | - Naoki Uemura
- Department of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba 1-1-1, Tennoudai Tsukuba Ibaraki 305-8573 Japan
| | - Tokushi Kizuka
- Department of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba 1-1-1, Tennoudai Tsukuba Ibaraki 305-8573 Japan
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7
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Zheng P, Jiang W, Qin Q, Li D. Dynamic Behavior of Rotation Transmission Nano-System in Helium Environment: A Molecular Dynamics Study. Molecules 2021; 26:molecules26175199. [PMID: 34500633 PMCID: PMC8434069 DOI: 10.3390/molecules26175199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/16/2021] [Accepted: 08/24/2021] [Indexed: 11/22/2022] Open
Abstract
The molecular dynamics (MD) method is used to investigate the influence of the shielding gas on the dynamic behavior of the heterogeneous rotation transmission nano-system (RTS) built on carbon nanotubes (CNTs) and boron nitride nanotube (BNNT) in a helium environment. In the heterogeneous RTS, the inner CNT acts as a rotor, the middle BNNT serves as a motor, and the outer CNT functions as a stator. The rotor will be actuated to rotate by the motor due to the interlayer van der Waals effects and the end effects. The MD simulation results show that, when the gas density is lower than a critical range, a stable signal of the rotor will arise on the output and the rotation transmission ratio (RRT) of RTS can reach 1.0, but as the gas density is higher than the critical range, the output signal of the rotor cannot be stable due to the sharp drop of the RRT caused by the large friction between helium and the RTS. The greater the motor input signal of RTS, the lower the critical working helium density range. The results also show that the system temperature and gas density are the two main factors affecting the RTS transmission behavior regardless of the size of the simulation box. Our MD results clearly indicate that in the working temperature range of the RTS from 100 K to 600 K, the higher the temperature and the lower the motor input rotation frequency, the higher the critical working helium density range allows.
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Affiliation(s)
- Pan Zheng
- School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China;
| | - Wugui Jiang
- School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China;
- Correspondence:
| | - Qinghua Qin
- Department of Engineering, Shenzhen MSU-BIT University, Shenzhen 518172, China;
| | - Duosheng Li
- School of Material Science and Engineering, Nanchang Hangkong University, Nanchang 330063, China;
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8
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Huang J, Fan Y, Guo Y, Liang Y. Axial strain effect on translational motion property of carbon nanotube thermal actuator. MOLECULAR SIMULATION 2020. [DOI: 10.1080/08927022.2020.1838511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Jianzhang Huang
- School of Civil Engineering, Guangzhou University, Guangzhou, People's Republic of China
| | - Yue Fan
- School of Civil Engineering, Guangzhou University, Guangzhou, People's Republic of China
| | - Yalan Guo
- School of Civil Engineering, Guangzhou University, Guangzhou, People's Republic of China
| | - Yingjing Liang
- School of Civil Engineering, Guangzhou University, Guangzhou, People's Republic of China
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9
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Pan D, Xu H, García de Abajo FJ. Anomalous Thermodiffusion of Electrons in Graphene. PHYSICAL REVIEW LETTERS 2020; 125:176802. [PMID: 33156664 DOI: 10.1103/physrevlett.125.176802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 09/07/2020] [Indexed: 06/11/2023]
Abstract
We reveal a dramatic departure of electron thermodiffusion in solids relative to the commonly accepted picture of the ideal free-electron gas model. In particular, we show that the interaction with the lattice and impurities, combined with a strong material dependence of the electron dispersion relation, leads to counterintuitive diffusion behavior, which we identify by comparing a two-dimensional electron gas (2DEG) and single-layer graphene. When subject to a temperature gradient ∇T, thermodiffusion of massless Dirac fermions in graphene exhibits an anomalous behavior with electrons moving along ∇T and accumulating in hot regions, in contrast to normal electron diffusion in a 2DEG with parabolic dispersion, where net motion against ∇T is observed, accompanied by electron depletion in hot regions. These findings bear fundamental importance for the understanding of the spatial electron dynamics in emerging materials, establishing close relations with other branches of physics dealing with electron systems under nonuniform temperature conditions.
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Affiliation(s)
- Deng Pan
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Hongxing Xu
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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10
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Leng J, Hu Y, Chang T. Nanoscale directional motion by angustotaxis. NANOSCALE 2020; 12:5308-5312. [PMID: 31872851 DOI: 10.1039/c9nr10108j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Directing motion of a nanoscale object on solid surfaces, in particular in an intrinsic way, is crucial for many aspects of nanotechnology applications. Here we report a novel intrinsic mechanism for nanoscale directional motion, termed angustotaxis, where a wide single walled carbon nanotube in a tapered channel drives itself toward the narrower end of the channel. The underlying physics of angustotaxis is attributed to the lower system potential when the nanotube is at a narrower region of the channel due to the increased contact area between the nanotube and the channel. Angustotaxis could lead to promising routes not only for nanoscale energy conversion from van der Waals potential to mechanical work, but also for mass transport like surface cleaning.
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Affiliation(s)
- Jiantao Leng
- Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Institute of Applied Mathematics and Mechanics, School of Mechanics and Engineering Science, Shanghai University, Shanghai, 200072, China.
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11
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Rajegowda R, Anandakrishnan A, Sathian SP. Phonon coupling induced thermophoresis of water confined in a carbon nanotube. Phys Chem Chem Phys 2020; 22:6081-6085. [DOI: 10.1039/d0cp00048e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The phonons in CNT are found to be suppressed by the presence of water, giving new insight into thermophoresis.
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Affiliation(s)
- Rakesh Rajegowda
- Department of Applied Mechanics
- Indian Institute of Technology Madras
- Chennai 600036
- India
| | | | - Sarith P. Sathian
- Department of Applied Mechanics
- Indian Institute of Technology Madras
- Chennai 600036
- India
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12
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Rajegowda R, Sathian SP. Analysing thermophoretic transport of water for designing nanoscale-pumps. Phys Chem Chem Phys 2018; 20:30321-30330. [PMID: 30484787 DOI: 10.1039/c8cp05521a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We propose a new design for thermally induced water pumping through carbon nanotubes by imposing a thermal gradient along the length of a carbon nanotube (CNT), which connects two water-filled reservoirs. We analyse the flow parameters by varying the imposed thermal gradient (4.62 to 20.98 K nm-1), the radius (0.81 to 1.89 nm) and the length (5 to 50 nm) of the CNT. Using molecular dynamics simulations, we compute the volumetric flow rate of the pump, velocity profiles of flow and thermophoretic forces acting on water molecules for various thermal gradients. The directed motion of water molecules is induced by the spatial variations of CNT-water energy interactions at the interface and the variations in the oscillation of the carbon atoms from hot to cold ends. The net flow and average velocity of water molecules are found to increase linearly with the applied thermal gradient, as well as with an increase in the radius and length of the CNT. We observe that nano-pumps with an increase in the radius and length of the CNT connecting the reservoirs perform better and also achieved higher efficiency levels. The analysis of the results indicates that the present design leads to a realistic system capable of providing continuous transportation of water leading to interesting practical applications in nanoscale devices.
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Affiliation(s)
- Rakesh Rajegowda
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036, India.
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13
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Abstract
Using large scale molecular dynamics simulations, we study the orientational dynamics of a heated Janus particle which exhibits self-propulsion. The asymmetry in the microscopic interaction of the colloid with the solvent is implemented by choosing different wetting parameters for the two halves of the sphere. This choice leads to a different microscopic Kapitza resistance across the solid-fluid boundary of the two halves of the sphere, and consequently a gradient in temperature is created across the poles of the sphere. It is this self-created temperature gradient which leads to a self-propulsion along the direction of the symmetry axis. In this article, we look at the orientational dynamics of such a system, as well as the subsequent enhancement of the translational diffusivity of the heated Janus colloid at late times. The orientational correlation of the symmetry axis is measured from the simulation and provides a direct access to the rotational diffusion constant. The heating leads to an increase in the rotational diffusivity of the colloid. We quantify this increase in rotational diffusion D r against the temperature difference δT ≡ T(R, 0) - T(R, π) across the poles of the Janus sphere as well as the average surface temperature difference ΔT ≡ T(R) - T(∞) from the ambient fluid. Since the rotational diffusion is determined by the complete flow field in the solvent, we illustrate that comparing D r against δT is misleading and is better quantified when compared against ΔT. The later quantification results in a data collapse for different choices of the microscopic interaction. The average propulsion velocity is also measured for different choices of the wetting parameter. The directionality of self-propulsion changes depending on the microscopic interaction. We show that whenever the attractive interaction of the colloid with the solvent is switched off, the phoretic mobility changes sign. Furthermore, the propulsion velocity is zero for heating below a certain threshold value. This is also corroborated by the probability distribution of the angle between the displacement vector Δr(t) ≡ r(t) - r(0) and the symmetry axis. Finally, we combine the measured propulsion velocity and the rotational diffusion time τ r = 1/2D r to estimate the enhancement in the long time diffusion coefficient of the particle.
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Affiliation(s)
- Dipanjan Chakraborty
- Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, S. A. S. Nagar, Manauli 140306, India
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14
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Rajegowda R, Kannam SK, Hartkamp R, Sathian SP. Thermophoretically driven water droplets on graphene and boron nitride surfaces. NANOTECHNOLOGY 2018; 29:215401. [PMID: 29498625 DOI: 10.1088/1361-6528/aab3a3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We investigate thermally driven water droplet transport on graphene and hexagonal boron nitride (h-BN) surfaces using molecular dynamics simulations. The two surfaces considered here have different wettabilities with a significant difference in the mode of droplet transport. The water droplet travels along a straighter path on the h-BN sheet than on graphene. The h-BN surface produced a higher driving force on the droplet than the graphene surface. The water droplet is found to move faster on h-BN surface compared to graphene surface. The instantaneous contact angle was monitored as a measure of droplet deformation during thermal transport. The characteristics of the droplet motion on both surfaces is determined through the moment scaling spectrum. The water droplet on h-BN surface showed the attributes of the super-diffusive process, whereas it was sub-diffusive on the graphene surface.
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Affiliation(s)
- Rakesh Rajegowda
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036, India
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15
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Fu L, Merabia S, Joly L. Understanding Fast and Robust Thermo-osmotic Flows through Carbon Nanotube Membranes: Thermodynamics Meets Hydrodynamics. J Phys Chem Lett 2018; 9:2086-2092. [PMID: 29624390 DOI: 10.1021/acs.jpclett.8b00703] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Following our recent theoretical prediction of the giant thermo-osmotic response of the water-graphene interface, we explore the practical implementation of waste heat harvesting with carbon-based membranes, focusing on model membranes of carbon nanotubes (CNT). To that aim, we combine molecular dynamics simulations and an analytical model considering the details of hydrodynamics in the membrane and at the tube entrances. The analytical model and the simulation results match quantitatively, highlighting the need to take into account both thermodynamics and hydrodynamics to predict thermo-osmotic flows through membranes. We show that, despite viscous entrance effects and a thermal short-circuit mechanism, CNT membranes can generate very fast thermo-osmotic flows, which can overcome the osmotic pressure of seawater. We then show that in small tubes confinement has a complex effect on the flow and can even reverse the flow direction. Beyond CNT membranes, our analytical model can guide the search for other membranes to generate fast and robust thermo-osmotic flows.
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Affiliation(s)
- Li Fu
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne , France
| | - Samy Merabia
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne , France
| | - Laurent Joly
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne , France
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16
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Guo Z, Zhang H, Li J, Leng J, Zhang Y, Chang T. An intrinsic energy conversion mechanism via telescopic extension and retraction of concentric carbon nanotubes. NANOSCALE 2018; 10:4897-4903. [PMID: 29480296 DOI: 10.1039/c7nr07971k] [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 conversion of other forms of energy into mechanical work through the geometrical extension and retraction of nanomaterials has a wide variety of potential applications, including for mimicking biomotors. Here, using molecular dynamics simulations, we demonstrate that there exists an intrinsic energy conversion mechanism between thermal energy and mechanical work in the telescopic motions of double-walled carbon nanotubes (DWCNTs). A DWCNT can inherently convert heat into mechanical work in its telescopic extension process, while convert mechanical energy into heat in its telescopic retraction process. These two processes are nearly thermodynamically reversible. The underlying mechanism for this energy conversion is that the configurational entropy changes with the telescopic overlapping length of concentric individual tubes. We also find that the entropy effect enlarges with the decreasing intertube space of DWCNTs. As a result, the spontaneous telescopic motion of a condensed DWCNT can be switched to extrusion by increasing the system temperature above a critical value. These findings are important for fundamentally understanding the mechanical behavior of concentric nanotubes, and may have general implications in the application of DWCNTs as linear motors in nanodevices.
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Affiliation(s)
- Zhengrong Guo
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, People's Republic of China.
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17
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Cheng Y, Zhang G, Zhang Y, Chang T, Pei QX, Cai Y, Zhang YW. Large diffusion anisotropy and orientation sorting of phosphorene nanoflakes under a temperature gradient. NANOSCALE 2018; 10:1660-1666. [PMID: 29319094 DOI: 10.1039/c7nr07226k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We perform molecular dynamics simulations to investigate the motion of phosphorene nanoflakes on a large graphene substrate under a thermal gradient. It is found that the atomic interaction between the graphene substrate and the phosphorene nanoflake generates distinct rates of motion for phosphorene nanoflakes with different orientations. Remarkably, for square phosphorene nanoflakes, the motion of zigzag-oriented nanoflakes is 2-fold faster than those of armchair-oriented and randomly-oriented nanoflakes. This large diffusion anisotropy suggests that sorting of phosphorene nanoflakes into specific orientations can be realized by a temperature gradient. The findings here provide interesting insights into strong molecular diffusion anisotropy and offer a novel route for manipulating two-dimensional materials.
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Affiliation(s)
- Yuan Cheng
- Institute of High Performance Computing, A*STAR, Singapore 138632.
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18
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Oyarzua E, Walther JH, Zambrano HA. Water thermophoresis in carbon nanotubes: the interplay between thermophoretic and friction forces. Phys Chem Chem Phys 2018; 20:3672-3677. [DOI: 10.1039/c7cp05749k] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
MD simulations show that the thermophoretic force is not velocity dependent while the friction force increases with the droplet speed.
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Affiliation(s)
- Elton Oyarzua
- Department of Chemical Engineering
- Universidad de Concepcion
- Concepcion
- Chile
| | - Jens H. Walther
- Department of Mechanical Engineering
- Technical University of Denmark
- Kgs. Lyngby
- Denmark
- Computational Science and Engineering Laboratory
| | - Harvey A. Zambrano
- Department of Chemical Engineering
- Universidad de Concepcion
- Concepcion
- Chile
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19
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Oyarzua E, Walther JH, Megaridis CM, Koumoutsakos P, Zambrano HA. Carbon Nanotubes as Thermally Induced Water Pumps. ACS NANO 2017; 11:9997-10002. [PMID: 28953353 DOI: 10.1021/acsnano.7b04177] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Thermal Brownian motors (TBMs) are nanoscale machines that exploit thermal fluctuations to provide useful work. We introduce a TBM-based nanopump which enables continuous water flow through a carbon nanotube (CNT) by imposing an axial thermal gradient along its surface. We impose spatial asymmetry along the CNT by immobilizing certain points on its surface. We study the performance of this molecular motor using molecular dynamics (MD) simulations. From the MD trajectories, we compute the net water flow and the induced velocity profiles for various imposed thermal gradients. We find that spatial asymmetry modifies the vibrational modes of the CNT induced by the thermal gradient, resulting in a net water flow against the thermal gradient. Moreover, the kinetic energy associated with the thermal oscillations rectifies the Brownian motion of the water molecules, driving the flow in a preferred direction. For imposed thermal gradients of 0.5-3.3 K/nm, we observe continuous net flow with average velocities up to 5 m/s inside CNTs with diameters of 0.94, 1.4, and 2.0 nm. The results indicate that the CNT-based asymmetric thermal motor can provide a controllable and robust system for delivery of continuous water flow with potential applications in integrated nanofluidic devices.
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Affiliation(s)
- Elton Oyarzua
- Department of Chemical Engineering, Universidad de Concepcion , Concepcion 4030000, Chile
| | - Jens Honore Walther
- Department of Mechanical Engineering, Technical University of Denmark , DK-2800 Kongens Lyngby, Denmark
- Computational Science and Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich , CH-8092 Zurich, Switzerland
| | - Constantine M Megaridis
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago , Chicago, Illinois 60607, United States
| | - Petros Koumoutsakos
- Computational Science and Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich , CH-8092 Zurich, Switzerland
| | - Harvey A Zambrano
- Department of Chemical Engineering, Universidad de Concepcion , Concepcion 4030000, Chile
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20
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Abstract
The textbook thermophoretic force which acts on a body in a fluid is proportional to the local temperature gradient. The same is expected to hold for the macroscopic drift behavior of a diffusive cluster or molecule physisorbed on a solid surface. The question we explore here is whether that is still valid on a 2D membrane such as graphene at short sheet length. By means of a nonequilibrium molecular dynamics study of a test system-a gold nanocluster adsorbed on free-standing graphene clamped between two temperatures [Formula: see text] apart-we find a phoretic force which for submicron sheet lengths is parallel to, but basically independent of, the local gradient magnitude. This identifies a thermophoretic regime that is ballistic rather than diffusive, persisting up to and beyond a 100-nanometer sheet length. Analysis shows that the phoretic force is due to the flexural phonons, whose flow is known to be ballistic and distance-independent up to relatively long mean-free paths. However, ordinary harmonic phonons should only carry crystal momentum and, while impinging on the cluster, should not be able to impress real momentum. We show that graphene and other membrane-like monolayers support a specific anharmonic connection between the flexural corrugation and longitudinal phonons whose fast escape leaves behind a 2D-projected mass density increase endowing the flexural phonons, as they move with their group velocity, with real momentum, part of which is transmitted to the adsorbate through scattering. The resulting distance-independent ballistic thermophoretic force is not unlikely to possess practical applications.
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21
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Rajegowda R, Kannam SK, Hartkamp R, Sathian SP. Thermophoretic transport of ionic liquid droplets in carbon nanotubes. NANOTECHNOLOGY 2017; 28:155401. [PMID: 28230533 DOI: 10.1088/1361-6528/aa6290] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Thermal-gradient induced transport of ionic liquid (IL) and water droplets through a carbon nanotube (CNT) is investigated in this study using molecular dynamics simulations. Energetic analysis indicates that IL transport through a CNT is driven primarily by the fluid-solid interaction, while fluid-fluid interactions dominate in water-CNT systems. Droplet diffusion analysis via the moment scaling spectrum reveals sub-diffusive motion of the IL droplet, in contrast to the self-diffusive motion of the water droplet. The Soret coefficient and energetic analysis of the systems suggest that the CNT shows more affinity for interaction with IL than with the water droplet. Thermophoretic transport of IL is shown to be feasible, which can create new opportunities in nanofluidic applications.
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Affiliation(s)
- Rakesh Rajegowda
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036, India
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22
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Leng J, Guo Z, Zhang H, Chang T, Guo X, Gao H. Negative Thermophoresis in Concentric Carbon Nanotube Nanodevices. NANO LETTERS 2016; 16:6396-6402. [PMID: 27626825 DOI: 10.1021/acs.nanolett.6b02815] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Positive and negative thermophoresis in fluids has found widespread applications from mass transport to molecule manipulation. In solids, although positive thermophoresis has been recently discovered in both theoretical and experimental studies, negative thermophoresis has never been reported. Here we reveal via molecular dynamics simulations that negative thermophoresis does exist in solids. We consider the motion of a single walled carbon nanotube nested inside of two separate outer tubes held at different temperatures. It is found that a sufficiently long inner tube will undergo negative thermophoresis, whereas positive thermophoresis is favorable for a relatively short inner tube. Mechanisms for the observed positive thermophoresis and negative thermophoresis are shown to be totally different. In positive thermophoresis, the driving force comes mainly from the thermally induced edge force and the interlayer attraction force, whereas the driving force for negative thermophoresis is mainly due to the thermal gradient force. These findings have enriched our knowledge of the fundamental driving mechanisms for thermophoresis in solids and may stimulate its further applications in nanotechnology.
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Affiliation(s)
- Jiantao Leng
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University , Shanghai 200072, People's Republic of China
| | - Zhengrong Guo
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University , Shanghai 200072, People's Republic of China
| | - Hongwei Zhang
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University , Shanghai 200072, People's Republic of China
| | - Tienchong Chang
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University , Shanghai 200072, People's Republic of China
| | - Xingming Guo
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University , Shanghai 200072, People's Republic of China
| | - Huajian Gao
- School of Engineering, Brown University , Providence, Rhode Island 02912, United States
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23
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Huang J, Han Q. Controllable nanoscale rotating actuator system based on carbon nanotube and graphene. NANOTECHNOLOGY 2016; 27:155501. [PMID: 26934619 DOI: 10.1088/0957-4484/27/15/155501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A controllable nanoscale rotating actuator system consisting of a double carbon nanotube and graphene driven by a temperature gradient is proposed, and its rotating dynamics performance and driving mechanism are investigated through molecular dynamics simulations. The outer tube exhibits stable pure rotation with certain orientation under temperature gradient and the steady rotational speed rises as the temperature gradient increases. It reveals that the driving torque is caused by the difference of atomic van der Waals potentials due to the temperature gradient and geometrical features of carbon nanotube. A theoretical model for driving torque is established based on lattice dynamics theory and its predicted results agree well with molecular dynamics simulations. Further discussion is taken according to the theoretical model. The work in this study would be a guide for design and application of controllable nanoscale rotating devices based on carbon nanotubes and graphene.
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Affiliation(s)
- Jianzhang Huang
- Department of Engineering Mechanics, School of Civil Engineering and Transportation, South China University of Technology, Guangzhou, Guangdong Province 510640, People's Republic of China
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24
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Prasad MVD, Bhattacharya B. Phonon Scattering Dynamics of Thermophoretic Motion in Carbon Nanotube Oscillators. NANO LETTERS 2016; 16:2174-2180. [PMID: 26965789 DOI: 10.1021/acs.nanolett.5b04014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Using phonon wave packet molecular dynamics simulations, we find that anomalous longitudinal acoustic (LA) mode phonon scattering in low to moderate energy ranges is responsible for initiating thermophoretic motion in carbon nanotube oscillators. The repeated scattering of a single mode LA phonon wave packet near the ends of the inner nanotube provides a net unbalanced force that, if large enough, initiates thermophoresis. By applying a coherent phonon pulse on the outer tube, which generalizes the single mode phonon wave packet, we are able to achieve thermophoresis in a carbon nanotube oscillator. We also find the nature of the unbalanced force on end-atoms to be qualitatively similar to that under an imposed thermal gradient. The thermodiffusion coefficient obtained for a range of thermal gradients and core lengths suggest that LA phonon scattering is the dominant mechanism for thermophoresis in longer cores, whereas for shorter cores, it is the highly diffusive mechanism that provides the effective force.
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Affiliation(s)
- Matukumilli V D Prasad
- Advanced Technology Development Centre, Indian Institute of Technology Kharagpur , Kharagpur, West Bengal 721302, India
| | - Baidurya Bhattacharya
- Civil Engineering Department, Indian Institute of Technology Kharagpur , Kharagpur, West Bengal 721302, India
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25
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Zhao K, Wu H. Fast Water Thermo-pumping Flow Across Nanotube Membranes for Desalination. NANO LETTERS 2015; 15:3664-3668. [PMID: 25928736 DOI: 10.1021/nl504236g] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Development of high-efficiency and low-cost seawater desalination technologies is critical to meet global water crisis. Here we report a fast water pumping method in which the water molecules in seawater are continuously pumped across nanotube membranes driven by a small temperature difference, opening the possibility of high-throughput small-scale desalination devices driven by low-grade thermal energy. Using molecular dynamics simulations, we show that an equivalent driving pressure of 5.3 MPa is achieved with a temperature difference of only 15 K. The remarkable water pumping ability is attributed to the asymmetric thermal fluctuation of water molecules. With this method, a 10 cm(2) nanotube membrane with 1.5 × 10(13) pores per cm(2) will produce freshwater with a flow rate of 7.77 L/h under a small temperature difference of 15 K.
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Affiliation(s)
- Kuiwen Zhao
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Huiying Wu
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
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26
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Chang T, Zhang H, Guo Z, Guo X, Gao H. Nanoscale directional motion towards regions of stiffness. PHYSICAL REVIEW LETTERS 2015; 114:015504. [PMID: 25615480 DOI: 10.1103/physrevlett.114.015504] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Indexed: 05/14/2023]
Abstract
How to induce nanoscale directional motion via some intrinsic mechanisms pertaining to a nanosystem remains a challenge in nanotechnology. Here we show via molecular dynamics simulations that there exists a fundamental driving force for a nanoscale object to move from a region of lower stiffness toward one of higher stiffness on a substrate. Such nanoscale directional motion is induced by the difference in effective van der Waals potential energy due to the variation in stiffness of the substrate; i.e., all other conditions being equal, a nanoscale object on a stiffer substrate has lower van der Waals potential energy. This fundamental law of nanoscale directional motion could lead to promising routes for nanoscale actuation and energy conversion.
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Affiliation(s)
- Tienchong Chang
- State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China and Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, People's Republic of China
| | - Hongwei Zhang
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, People's Republic of China
| | - Zhengrong Guo
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, People's Republic of China and School of Engineering, Brown University, Providence, Rhode Island 02912, USA
| | - Xingming Guo
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, People's Republic of China
| | - Huajian Gao
- School of Engineering, Brown University, Providence, Rhode Island 02912, USA
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27
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Cai K, Li Y, Qin QH, Yin H. Gradientless temperature-driven rotating motor from a double-walled carbon nanotube. NANOTECHNOLOGY 2014; 25:505701. [PMID: 25420489 DOI: 10.1088/0957-4484/25/50/505701] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Rotation of the inner tube in a double-walled carbon nanotube (DWCNT) system with a fixed outer tube is investigated and found to be inducible by a relatively high uniform temperature (say, 300 K). We also found the mechanism of a gradientless temperature-driven rotating motor lies in the inner tube losing its geometric symmetry in a high-temperature field. This mechanism can be taken as a guide for designing a motor from such a bi-tube system. Using a computational molecular dynamics (CMD) approach and the adaptive intermolecular reactive empirical bond order (AIREBO) potential, the dynamic behavior of a bi-tube system subjected to uniformly distributed temperature is studied. In particular, the effects of environmental temperature, boundary conditions of the outer tube, and intertube gap on the dynamic behavior of the bi-tube system are investigated. Numerical examples show that a bi-tube system with the inner tube having 0.335 nm of interlayer gap produces the highest rotational speed.
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Affiliation(s)
- K Cai
- College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, 712100, People's Republic of China
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28
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Becton M, Wang X. Thermal Gradients on Graphene to Drive Nanoflake Motion. J Chem Theory Comput 2014; 10:722-30. [PMID: 26580049 DOI: 10.1021/ct400963d] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Thermophoresis has been emerging as a novel technique for manipulating nanoscale particles. Materials with good thermal conductivity and low surface friction, such as graphene, are best suited to serve as a platform for solid-solid transportations or manipulations. Here we employ nonequilibrium molecular dynamics simulations to explore the feasibility of utilizing a thermal gradient on a large graphene substrate to control the motion of a small graphene nanoflake on it. Attempts to systematically investigate the mechanism of graphene-graphene transportation have centered on the fundamental driving mechanism of the motion and the quantitative effect of significant parameters such as temperature gradient and geometry of graphene on the motion of the nanoflake. Simulation results have demonstrated that temperature gradient plays the pivotal role in the evolution of the motion of the nanoflake on the graphene surface. Also, the geometry of nanoflakes has presented an intriguing signature on the motion of the nanoflake, which shows the nanoflakes with a circular shape move slower but rotate faster than other shapes with the identical area. It reveals that edge effects can stabilize the angular motion of thermophoretically driven particles. An interesting relation between the effective initial driving force and temperature gradient has been quantitatively captured by employing the steered molecular dynamics. These findings will provide fundamental insights into the motion of nanodevices on a solid surface due to thermophoresis, and will offer the novel view for manipulating nanoscale particles on a solid surface in techniques such as cell separation, water purification, and chemical extraction.
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Affiliation(s)
- Matthew Becton
- College of Engineering, University of Georgia , Athens, Georgia 30602, United States
| | - Xianqiao Wang
- College of Engineering, University of Georgia , Athens, Georgia 30602, United States
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29
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Xu L, Hu YZ, Ma TB, Wang H. Tunable giant anisotropic diffusion of water sub-monolayers between graphene layers. NANOTECHNOLOGY 2013; 24:505504. [PMID: 24284607 DOI: 10.1088/0957-4484/24/50/505504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We investigate the in-plane confinement effect of two graphene layers on the diffusion behaviour of water sub-monolayers using molecular dynamics simulations. An unexpected fast diffusion state with giant anisotropy is observed when the two confining graphene walls have certain shifts applied to their relative positions. The phenomenon is mainly attributed to the smooth one-dimensional potential channels produced by the composition effect of the potential energy landscapes of the two graphene walls, and the concerted motion of water molecules due to hydrogen bonding. Unique duality in the diffusion mechanism is observed in the fast diffusion state, as is ballistic motion along the potential channels and Fickian diffusion across such channels. The smooth potential channels can be created in certain directions simply by shifting the confining walls, which provides a novel measure to manipulate the motion of confined molecules in real-time.
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Affiliation(s)
- Liang Xu
- State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, People's Republic of China
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30
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Zhu L, Li X, Wu S, Nguyen KT, Yan H, Ågren H, Zhao Y. Chirality Control for in Situ Preparation of Gold Nanoparticle Superstructures Directed by a Coordinatable Organogelator. J Am Chem Soc 2013; 135:9174-80. [DOI: 10.1021/ja403722t] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Liangliang Zhu
- Division of Chemistry and Biological
Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore
637371
| | - Xin Li
- Department of Theoretical
Chemistry
and Biology, School of Biotechnology, KTH Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Shaojue Wu
- Division of Chemistry and Biological
Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore
637371
| | - Kim Truc Nguyen
- Division of Chemistry and Biological
Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore
637371
| | - Hong Yan
- Division of Chemistry and Biological
Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore
637371
| | - Hans Ågren
- Department of Theoretical
Chemistry
and Biology, School of Biotechnology, KTH Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Yanli Zhao
- Division of Chemistry and Biological
Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore
637371
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
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31
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Affiliation(s)
- Petr Král
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
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32
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Lohrasebi A, Nouri N. Molecular dynamics modelling of an electrical-driven linear nanopump. MOLECULAR SIMULATION 2012. [DOI: 10.1080/08927022.2012.659181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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33
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A rotary nano ion pump: a molecular dynamics study. J Mol Model 2012; 18:4191-7. [PMID: 22538506 DOI: 10.1007/s00894-012-1403-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 03/07/2012] [Indexed: 10/28/2022]
Abstract
The dynamics of a rotary nano ion pump, inspired by the F (0) part of the F(0)F(1)-ATP synthase biomolecular motor, were investigated. This nanopump is composed of a rotor, which is constructed of two carbon nanotubes with benzene rings, and a stator, which is made of six graphene sheets. The molecular dynamics (MD) method was used to simulate the dynamics of the ion nanopump. When the rotor of the nanopump rotates mechanically, an ion gradient will be generated between the two sides of the nanopump. It is shown that the ion gradient generated by the nanopump is dependant on parameters such as the rotary frequency of the rotor, temperature and the amounts and locations of the positive and negative charges of the stator part of the nanopump. Also, an electrical potential difference is generated between the two sides of the pump as a result of its operation.
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34
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Wei N, Wang HQ, Zheng JC. Nanoparticle manipulation by thermal gradient. NANOSCALE RESEARCH LETTERS 2012; 7:154. [PMID: 22364240 PMCID: PMC3306267 DOI: 10.1186/1556-276x-7-154] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 02/26/2012] [Indexed: 05/27/2023]
Abstract
A method was proposed to manipulate nanoparticles through a thermal gradient. The motion of a fullerene molecule enclosed inside a (10, 10) carbon nanotube with a thermal gradient was studied by molecular dynamics simulations. We created a one-dimensional potential valley by imposing a symmetrical thermal gradient inside the nanotube. When the temperature gradient was large enough, the fullerene sank into the valley and became trapped. The escaping velocities of the fullerene were evaluated based on the relationship between thermal gradient and thermophoretic force. We then introduced a new way to manipulate the position of nanoparticles by translating the position of thermostats with desirable thermal gradients. Compared to nanomanipulation using a scanning tunneling microscope or an atomic force microscope, our method for nanomanipulation has a great advantage by not requiring a direct contact between the probe and the object.
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Affiliation(s)
- Ning Wei
- Department of Physics and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, 361005, China
| | - Hui-Qiong Wang
- Department of Physics and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, 361005, China
- Fujian Key Lab of Semiconductor Materials and Applications, Xiamen University, Xiamen, 361005, China
| | - Jin-Cheng Zheng
- Department of Physics and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, 361005, China
- Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Xiamen University, Xiamen, 361005, China
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35
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Abstract
We show by molecular dynamics simulations that water nanodroplets can be transported along and around the surfaces of vibrated carbon nanotubes. In our simulations, a nanodroplet with a diameter of ∼4 nm is adsorbed on a (10,0) single-wall carbon nanotube, which is vibrated at one end with a frequency of 208 GHz and an amplitude of 1.2 nm. The generated linearly polarized transverse acoustic waves pass linear momentum to the nanodroplet, which becomes transported along the nanotube with a velocity of ∼30 nm/ns. When circularly polarized waves are passed along the nanotubes, the nanodroplets rotate around them and eventually become ejected from their surfaces when their angular velocity is ∼50 rad/ns.
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Affiliation(s)
- John T Russell
- †Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Boyang Wang
- †Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Petr Král
- †Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
- ‡Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
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36
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Shenai PM, Xu Z, Zhao Y. Thermal-gradient-induced interaction energy ramp and actuation of relative axial motion in short-sleeved double-walled carbon nanotubes. NANOTECHNOLOGY 2011; 22:485702. [PMID: 22056730 DOI: 10.1088/0957-4484/22/48/485702] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We investigate the phenomenon of actuation of relative linear motion in double-walled carbon nanotubes (DWNTs) resulting from a temperature gradient. Molecular dynamics simulations of DWNTs with short outer tube reveal that the outer tube is driven towards the cold end of the long inner tube. It is also found that the terminal velocity of the sleeve roughly depends linearly on the applied thermal gradient. We calculate the inter-tube interaction energy surface which is revealed to have a gradient depending upon the applied thermal gradient. Consequently, it is proposed that the origin of the thermophoretic motion of the outer tube may be attributed partially to the existence of such an energy gradient. A simple analytical model is presented accounting for the gradient in energy profile as well as the effect of biased thermal noise. It is shown that the proposed model predicts the dynamical behaviour of the long-time performance reasonably well.
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Affiliation(s)
- Prathamesh M Shenai
- School of Materials Science and Engineering, Nanyang Technological University, Singapore
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37
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Lohrasebi A, Neek-Amal M, Ejtehadi MR. Directed motion of C60 on a graphene sheet subjected to a temperature gradient. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:042601. [PMID: 21599222 DOI: 10.1103/physreve.83.042601] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2010] [Revised: 12/20/2010] [Indexed: 05/30/2023]
Abstract
Nonequilibrium molecular dynamics simulations are used to study the motion of a C(60) molecule on a graphene sheet subjected to a temperature gradient. The C(60) molecule is actuated and moves along the system while it just randomly dances along the perpendicular direction. Increasing the temperature gradient increases the directed velocity of C(60). It is found that the free energy decreases as the C(60) molecule moves toward the cold end. The driving mechanism based on the temperature gradient suggests the construction of nanoscale graphene-based motors.
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Affiliation(s)
- A Lohrasebi
- Department of Physics, University of Isfehan, Isfehan, Iran
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38
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Rurali R, Hernández E. Thermally induced directed motion of fullerene clusters encapsulated in carbon nanotubes. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.07.081] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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39
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Zhou J, Song H, Chen X, Huo J. Diffusion of Metal in a Confined Nanospace of Carbon Nanotubes Induced by Air Oxidation. J Am Chem Soc 2010; 132:11402-5. [DOI: 10.1021/ja105712w] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jisheng Zhou
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Huaihe Song
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Xiaohong Chen
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Junping Huo
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
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Zambrano HA, Walther JH, Jaffe RL. Thermally driven molecular linear motors: A molecular dynamics study. J Chem Phys 2009; 131:241104. [DOI: 10.1063/1.3281642] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Hou QW, Cao BY, Guo ZY. Thermal gradient induced actuation in double-walled carbon nanotubes. NANOTECHNOLOGY 2009; 20:495503. [PMID: 19893145 DOI: 10.1088/0957-4484/20/49/495503] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Molecular dynamics simulations are applied to investigate the thermal gradient induced actuation in double-walled carbon nanotubes, where a temperature difference can actuate the relative motion of double-walled carbon nanotubes. The thermal driving force calculated through a stationary scheme is on the order of pico Newtons for a 1 K nm(-1) temperature gradient. The driving force is approximately proportional to the temperature gradient, but not sensitive to the system temperature. For the outer tube longer than 5 nm, the thermal driving force is nearly constant. For the outer tube shorter than 5 nm, however, the driving force decreases with decreasing tube length. The motion trace is found to depend on both the chirality pair and system temperature. A critical temperature can be defined by the potential barrier perpendicular to the minimum energy track of potential patterns. When the system temperature is higher than the critical temperature, the motion shows random behavior. When the system temperature is lower than the critical temperature, the motion, translational and/or rotational, is confined within the minimum energy track, which is indicative of the feasibility of directional control.
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Affiliation(s)
- Quan-Wen Hou
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, People's Republic of China
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Shiomi J, Maruyama S. Water transport inside a single-walled carbon nanotube driven by a temperature gradient. NANOTECHNOLOGY 2009; 20:055708. [PMID: 19417367 DOI: 10.1088/0957-4484/20/5/055708] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In this work, by means of molecular dynamics simulations, we consider the mass transport of a water cluster inside a single-walled carbon nanotube (SWNT) with a diameter of about 1.4 nm. The influence of the non-equilibrium thermal environment on the confined water cluster has been investigated by imposing a longitudinal temperature gradient on the SWNT. It is demonstrated that the water cluster is transported with an average acceleration proportional to the temperature gradient. Additional equilibrium simulations suggest that the temperature dependence of the potential energy of the confined water is sufficient to realize the transport. In particular, for a system with a hydrophobic interface, the water-water intrinsic potential energy appears to play a dominant role. The transport simulations were also performed for a system with a junction between two different SWNTs. The results suggest that an angstrom difference in diameter may result in a large barrier for water being transported through a small diameter SWNT.
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Affiliation(s)
- J Shiomi
- Department of Mechanical Engineering, The University of Tokyo, Tokyo, Japan.
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Barreiro A, Rurali R, Hernández ER, Moser J, Pichler T, Forró L, Bachtold A. Subnanometer motion of cargoes driven by thermal gradients along carbon nanotubes. Science 2008; 320:775-8. [PMID: 18403675 DOI: 10.1126/science.1155559] [Citation(s) in RCA: 168] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
An important issue in nanoelectromechanical systems is developing small electrically driven motors. We report on an artificial nanofabricated motor in which one short carbon nanotube moves relative to another coaxial nanotube. A cargo is attached to an ablated outer wall of a multiwalled carbon nanotube that can rotate and/or translate along the inner nanotube. The motion is actuated by imposing a thermal gradient along the nanotube, which allows for subnanometer displacements, as opposed to an electromigration or random walk effect.
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Affiliation(s)
- Amelia Barreiro
- Centre d'Investigacions en Nanociencia i Nanotecnologia, Campus de la Universitat Autònoma de Barcelona (UAB), E-08193 Bellaterra, Spain
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