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Huang Y, Wu C, Dai J, Liu B, Cheng X, Li X, Cao Y, Chen J, Li Z, Tang J. Tunable Self-Thermophoretic Nanomotors with Polymeric Coating. J Am Chem Soc 2023; 145:19945-19952. [PMID: 37641545 DOI: 10.1021/jacs.3c06322] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Thermophoretic micro/nanomotors (MNMs) generate self-propulsion without a chemical reaction. Intrinsically, this promises excellent biocompatibility and is thus suitable for biomedical applications. However, their propulsion efficiency is severely limited due to the poor understanding of the thermophoretic process, which dominates the conversion from thermal energy into mechanical movement. We here developed a series of self-thermophoresis light-powered MNMs with variable surface coatings and discovered obvious self-thermophoresis propulsion enhancement of the polymeric layer. An intrinsically negative self-thermophoretic movement is also observed for the first time in the MNM system. We propose that enthalpic contributions from polymer-solvent interactions should play a fundamental role in the self-thermophoretic MNMs. Quantitative microcalorimetry and molecular dynamics simulations are performed to support our hypothesis. The polymer solvation enthalpy and coating thickness influences on self-thermophoresis are investigated, further highlighting the essential enthalpy contributions to thermophoresis. Our work indicates that surface grafting would be important in designing high-efficiency thermally driven nanorobotic systems for biomedical applications.
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Affiliation(s)
- Yaxin Huang
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China
| | - Changjin Wu
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China
| | - Jia Dai
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China
| | - Biyuan Liu
- Department of Mechanical and Aerospace Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Xiang Cheng
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China
| | - Xiaofeng Li
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China
| | - Yingnan Cao
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China
| | - Jingyuan Chen
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China
| | - Zhigang Li
- Department of Mechanical and Aerospace Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Jinyao Tang
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China
- State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Hong Kong 999077, China
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2
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Zhou Y, Yang Y, Zhu C, Yang M, Hu Y. Numerical Analysis of Thermophoresis of a Charged Spheroidal Colloid in Aqueous Media. MICROMACHINES 2021; 12:mi12020224. [PMID: 33672210 PMCID: PMC7926884 DOI: 10.3390/mi12020224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 02/13/2021] [Accepted: 02/13/2021] [Indexed: 11/17/2022]
Abstract
Thermophoresis of charged colloids in aqueous media has wide applications in biology. Most existing studies of thermophoresis focused on spherical particles, but biological compounds are usually non-spherical. The present paper reports a numerical analysis of the thermophoresis of a charged spheroidal colloid in aqueous media. The model accounts for the strongly coupled temperature field, the flow field, the electric potential field, and the ion concentration field. Numerical simulations revealed that prolate spheroids move faster than spherical particles, and oblate spheroids move slower than spherical particles. For the arbitrary electric double layer (EDL) thickness, the thermodiffusion coefficient of prolate (oblate) spheroids increases (decreases) with the increasing particle’s dimension ratio between the major and minor semiaxes. For the extremely thin EDL case, the hydrodynamic effect is significant, and the thermodiffusion coefficient for prolate (oblate) spheroids converges to a fixed value with the increasing particle’s dimension ratio. For the extremely thick EDL case, the particle curvature’s effect also becomes important, and the increasing (decreasing) rate of thermodiffusion coefficient for prolate (oblate) spheroids is reduced slightly.
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Affiliation(s)
| | | | | | | | - Yi Hu
- Correspondence: ; Tel.: +86-27-8654-0330
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Tsuji T, Matsumoto Y, Kugimiya R, Doi K, Kawano S. Separation of Nano- and Microparticle Flows Using Thermophoresis in Branched Microfluidic Channels. MICROMACHINES 2019; 10:mi10050321. [PMID: 31083630 PMCID: PMC6562922 DOI: 10.3390/mi10050321] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 05/06/2019] [Accepted: 05/07/2019] [Indexed: 12/15/2022]
Abstract
Particle flow separation is a useful technique in lab-on-a-chip applications to selectively transport dispersed phases to a desired branch in microfluidic devices. The present study aims to demonstrate both nano- and microparticle flow separation using microscale thermophoresis at a Y-shaped branch in microfluidic channels. Microscale thermophoresis is the transport of tiny particles induced by a temperature gradient in fluids where the temperature variation is localized in the region of micrometer order. Localized temperature increases near the branch are achieved using the Joule heat from a thin-film micro electrode embedded in the bottom wall of the microfluidic channel. The inlet flow of the particle dispersion is divided into two outlet flows which are controlled to possess the same flow rates at the symmetric branches. The particle flow into one of the outlets is blocked by microscale thermophoresis since the particles are repelled from the hot region in the experimental conditions used here. As a result, only the solvent at one of outlets and the residual particle dispersion at the other outlet are obtained, i.e., the separation of particles flows is achieved. A simple model to explain the dynamic behavior of the nanoparticle distribution near the electrode is proposed, and a qualitative agreement with the experimental results is obtained. The proposed method can be easily combined with standard microfluidic devices and is expected to facilitate the development of novel particle separation and filtration technologies.
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Affiliation(s)
- Tetsuro Tsuji
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Yuki Matsumoto
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Ryo Kugimiya
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Kentaro Doi
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Satoyuki Kawano
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
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Peng X, Lin L, Hill EH, Kunal P, Humphrey SM, Zheng Y. Optothermophoretic Manipulation of Colloidal Particles in Nonionic Liquids. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2018; 122:24226-24234. [PMID: 30766650 PMCID: PMC6369910 DOI: 10.1021/acs.jpcc.8b03828] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The response of colloidal particles to a light-controlled external temperature field can be harnessed for opto-thermophoretic manipulation of the particles. The thermoelectric effect is regarded as the driving force for thermophoretic trapping of particles at the light-irradiated hot region, which is thus limited to ionic liquids. Herein, we achieve opto-thermophoretic manipulation of colloidal particles in various non-ionic liquids, including water, ethanol, isopropyl alcohol and 1-butanol, and establish the physical mechanism of the manipulation at the molecular level. We reveal that the non-ionic driving force originates from a layered structure of solvent molecules at the particle-solvent interface, which is supported by molecular dynamics simulations. Furthermore, the effects of hydrophilicity, solvent type, and ionic strength on the layered interfacial structures and thus the trapping stability of particles are investigated, providing molecular-level insight into thermophoresis and guidance on interfacial engineering for optothermal manipulation.
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Affiliation(s)
- Xiaolei Peng
- Materials Science & Engineering Program and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Linhan Lin
- Materials Science & Engineering Program and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Eric H. Hill
- Materials Science & Engineering Program and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Pranaw Kunal
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712, USA
| | - Simon M. Humphrey
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712, USA
| | - Yuebing Zheng
- Materials Science & Engineering Program and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
- Corresponding Author:
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Yu S, Wang J, Xia G, Zong L. Thermophoretic force on nonspherical particles in the free-molecule regime. Phys Rev E 2018; 97:053106. [PMID: 29906953 DOI: 10.1103/physreve.97.053106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Indexed: 11/07/2022]
Abstract
The present paper is devoted to studying the thermophoresis of a nonspherical convex particle suspended in a gas with nonuniform temperature distribution in the free-molecule regime. Based on the gas kinetic theory and the assumption of a rigid-body collision for the gas-particle interaction, analytical expressions for the thermophoretic forces are obtained for several typical nonspherical bodies, including cylinders, spheroids, needles, disks, and cuboids. The orientation dependences of the thermophoretic forces and thermophoretic velocities are evaluated based on these expressions. It is found that the influence of the pitching effect of the nonspheres can be significant. The expressions for the orientation-averaged thermophoretic forces are also obtained under the assumption of a uniform particle orientation distribution.
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Affiliation(s)
- Song Yu
- Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, and Key Laboratory of Heat Transfer and Energy Conversion, Beijing Municipality, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, People's Republic of China
| | - Jun Wang
- Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, and Key Laboratory of Heat Transfer and Energy Conversion, Beijing Municipality, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, People's Republic of China
| | - Guodong Xia
- Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, and Key Laboratory of Heat Transfer and Energy Conversion, Beijing Municipality, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, People's Republic of China
| | - Luxiang Zong
- Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, and Key Laboratory of Heat Transfer and Energy Conversion, Beijing Municipality, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, People's Republic of China
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