1
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Gibouin F, Nalatamby D, Lidon P, Medina-Gonzalez Y. Molecular Rotors for In Situ Viscosity Mapping during Evaporation of Confined Fluid Mixtures. ACS APPLIED MATERIALS & INTERFACES 2024; 16:8066-8076. [PMID: 38316660 DOI: 10.1021/acsami.3c16808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Numerous formulation processes of materials involve a drying step, during which evaporation of a solvent from a multicomponent liquid mixture, often confined in a thin film or in a droplet, leads to concentration and assembly of nonvolatile compounds. While the basic phenomena ruling evaporation dynamics are known, precise modeling of practical situations is hindered by the lack of tools for local and time-resolved mapping of concentration fields in such confined systems. In this article, the use of fluorescence lifetime imaging microscopy and of fluorescent molecular rotors is introduced as a versatile, in situ, and quantitative method to map viscosity and concentration fields in confined, evaporating liquids. More precisely, the cases of drying of a suspended liquid film and of a sessile droplet of mixtures of fructose and water are investigated. Measured viscosity and concentration fields allow characterization of drying dynamics, in agreement with simple modeling of the evaporation process.
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Affiliation(s)
- Florence Gibouin
- Laboratoire du Futur, (LOF)─Solvay─CNRS─Université de Bordeaux, UMR 5258, Bordeaux, Pessac 33600, France
| | - Dharshana Nalatamby
- Laboratoire du Futur, (LOF)─Solvay─CNRS─Université de Bordeaux, UMR 5258, Bordeaux, Pessac 33600, France
| | - Pierre Lidon
- Laboratoire du Futur, (LOF)─Solvay─CNRS─Université de Bordeaux, UMR 5258, Bordeaux, Pessac 33600, France
| | - Yaocihuatl Medina-Gonzalez
- Laboratoire du Futur, (LOF)─Solvay─CNRS─Université de Bordeaux, UMR 5258, Bordeaux, Pessac 33600, France
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2
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Wang D, Lippmann M, Gäding J, Ehnes A, Novikov D, Meißner R, Seeck OH. Orientation order of a nonpolar molecular fluid compressed into a nanosmall space. NANOSCALE 2023; 15:8019-8028. [PMID: 37070420 DOI: 10.1039/d2nr06330a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The ordering structures of non-polar carbon tetrachloride liquid compressed to nano-scales between parallel substrates is studied in this work. The theoretical considerations show that the potential well formed by the confined parallel substrates induces orientational ordering of non-polar molecules. Through molecular dynamic (MD) simulations, the relations between various ordered structures of a non-polar liquid (carbon tetrachloride) and the confined gap size are demonstrated. The density distribution shows that the confinement does affect the ordering modes and induces an orientational ordering of molecules at the solid-liquid interface under extreme confinement conditions. This molecular orientation suggested from the theoretical model and MD simulation is directly supported by the experimental studies for the first time. The X-ray reflectivity data reveal a strong layering effect with splitting of the density profile in C and Cl-rich sublayers. The investigation shows that the liquid structure factor in confinement has a characteristic length similar to the short-range ordering in bulk, but the confined structure is strongly influenced by the surface potential and the interface properties. This introduces preferred molecular orientation and ordering which are not favorable in the bulk phase. As the orientational ordering is closely related to crystallization, our results provide a new perspective to control the crystallization in nano-confined space by compression.
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Affiliation(s)
- Dan Wang
- State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, No. 29 Yudao Street, Nanjing 210016, China
| | - Milena Lippmann
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany.
| | | | - Anita Ehnes
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany.
| | - Dmitri Novikov
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany.
| | - Robert Meißner
- Hamburg University of Technology, 21073 Hamburg, Germany
- Helmholtz-Zentrum Hereon, 21502 Geesthacht, Germany
| | - Oliver H Seeck
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany.
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3
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Hsu CC, Peng L, Hsia FC, Weber B, Bonn D, Brouwer AM. Molecular Probing of the Stress Activation Volume in Vapor Phase Lubricated Friction. ACS APPLIED MATERIALS & INTERFACES 2023; 15:12603-12608. [PMID: 36827622 PMCID: PMC9999409 DOI: 10.1021/acsami.3c00789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
When two solid objects slide over each other, friction results from the interactions between the asperities of the (invariably rough) surfaces. Lubrication happens when viscous lubricants separate the two surfaces and carry the load such that solid-on-solid contacts are avoided. Yet, even small amounts of low-viscosity lubricants can still significantly lower friction through a process called boundary lubrication. Understanding the origin of the boundary lubricating effect is hampered by challenges in measuring the interfacial properties of lubricants directly between the two surfaces. Here, we use rigidochromic fluorescent probe molecules to measure precisely what happens on a molecular scale during vapor-phase boundary lubrication of a polymer bead-on-glass interface. The probe molecules have a longer fluorescence lifetime in a confined environment, which allows one to measure the area of real contact between rough surfaces and infer the shear stress at the lubricated interfaces. The latter is shown to be proportional to the inverse of the local interfacial free volume determined using the measured fluorescence lifetime. The free volume can then be used in an Eyring-type model as the stress activation volume, allowing to collapse the data of stress as a function of sliding velocity and partial pressure of the vapor phase lubricant. This shows directly that as more boundary lubricant is applied, larger clusters of lubricant molecules become involved in the shear process thereby lowering the friction.
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Affiliation(s)
- Chao-Chun Hsu
- van
’t Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Liang Peng
- van
der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Feng-Chun Hsia
- van
der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- Advanced
Research Center for Nanolithography, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bart Weber
- van
der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- Advanced
Research Center for Nanolithography, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Daniel Bonn
- van
der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Albert M. Brouwer
- van
’t Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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4
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Shi K, Smith ER, Santiso EE, Gubbins KE. A perspective on the microscopic pressure (stress) tensor: History, current understanding, and future challenges. J Chem Phys 2023; 158:040901. [PMID: 36725519 DOI: 10.1063/5.0132487] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The pressure tensor (equivalent to the negative stress tensor) at both microscopic and macroscopic levels is fundamental to many aspects of engineering and science, including fluid dynamics, solid mechanics, biophysics, and thermodynamics. In this Perspective, we review methods to calculate the microscopic pressure tensor. Connections between different pressure forms for equilibrium and nonequilibrium systems are established. We also point out several challenges in the field, including the historical controversies over the definition of the microscopic pressure tensor; the difficulties with many-body and long-range potentials; the insufficiency of software and computational tools; and the lack of experimental routes to probe the pressure tensor at the nanoscale. Possible future directions are suggested.
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Affiliation(s)
- Kaihang Shi
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Edward R Smith
- Department of Mechanical and Aerospace Engineering, Brunel University London, Uxbridge, London, United Kingdom
| | - Erik E Santiso
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Keith E Gubbins
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
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5
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Stephens NM, Masching HP, Walid MKI, Petrich JW, Anderson JL, Smith EA. Temperature-Dependent Constrained Diffusion of Micro-Confined Alkylimidazolium Chloride Ionic Liquids. J Phys Chem B 2022; 126:4324-4333. [PMID: 35649257 DOI: 10.1021/acs.jpcb.2c01588] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Alkylimidazolium chloride ionic liquids (ILs) have many uses in a variety of separation systems, including micro-confined separation systems. To understand the separation mechanism in these systems, the diffusion properties of analytes in ILs under relevant operating conditions, including micro-confinement dimension and temperature, should be known. For example, separation efficiencies for various IL-based microextraction techniques are dependent on the sample volume and temperature. Temperature-dependent (20-100 °C) fluorescence recovery after photobleaching (FRAP) was utilized to determine the diffusion properties of a zwitterionic, hydrophilic dye, ATTO 647, in alkylimidazolium chloride ILs in micro-confined geometries. These micro-confined geometries were generated by sandwiching the IL between glass substrates that were separated by ∼1 to 100 μm. From the measured temperature-dependent FRAP data, we note alkyl chain length-, thickness-, and temperature-dependent diffusion coefficients, with values ranging from 0.021 to 46 μm2/s. Deviations from Brownian diffusion are observed at lower temperatures and increasingly less so at elevated temperatures; the differences are attributed to alterations in intermolecular interactions that reduce temperature-dependent nanoscale structural heterogeneities. The temperature- and thickness-dependent data provide a useful foundation for efficient design of micro-confined IL separation systems.
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Affiliation(s)
- Nicole M Stephens
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011-3111, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, United States
| | - Hayley P Masching
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011-3111, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, United States
| | - Mohammad K I Walid
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, United States
| | - Jacob W Petrich
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011-3111, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, United States
| | - Jared L Anderson
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011-3111, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, United States
| | - Emily A Smith
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011-3111, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, United States
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6
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Pan X, Wang C, Zhao C, Cheng T, Zheng A, Cao Y, Xu K. Assessment of cancer cell migration using a viscosity-sensitive fluorescent probe. Chem Commun (Camb) 2022; 58:4663-4666. [PMID: 35319548 DOI: 10.1039/d1cc07235h] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A novel viscosity probe (NV1) was developed for assessing cancer cell migration. NV1 can respond to changes of viscosity rapidly and exhibits high sensitivity in HepG2 cells treated with starvation, rotenone and nystatin. Importantly, NV1 was used for the first time to evaluate the relationship between intracellular viscosity changes and cancer cell migration and proved that increased intracellular viscosity inhibits cell migration while decreased intracellular viscosity promotes cell migration.
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Affiliation(s)
- Xiaohong Pan
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Shandong Normal University, Jinan 250014, P. R. China. .,School of Pharmacy, Binzhou Medical University, Yantai 264003, China
| | - Cheng Wang
- School of Pharmacy, Binzhou Medical University, Yantai 264003, China
| | - Congcong Zhao
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Shandong Normal University, Jinan 250014, P. R. China.
| | - Tingting Cheng
- School of Pharmacy, Binzhou Medical University, Yantai 264003, China
| | - Aishan Zheng
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Shandong Normal University, Jinan 250014, P. R. China.
| | - Yuru Cao
- The 2nd Medical College of Binzhou Medical University, Yantai 264003, China
| | - Kehua Xu
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Shandong Normal University, Jinan 250014, P. R. China.
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7
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Wang XN, Feng Y, Liu HZ, Zhang H, Yan ZC, Bai YW. Microstructure and corrosion behavior of Al 95−xNi xY 5 ( x = 7,10) glassy ribbons. RSC Adv 2022; 12:7199-7209. [PMID: 35424656 PMCID: PMC8982189 DOI: 10.1039/d1ra09189a] [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: 12/20/2021] [Accepted: 02/08/2022] [Indexed: 11/21/2022] Open
Abstract
In this work, we correlate the microstructure and passivation of the Al95−xNixY5 lightweight glassy ribbons (x = 7 and 10) using various techniques. The overdosed Ni (x = 10) can increase the melt viscosity and then deteriorate its glass-forming ability (GFA), ribbon formability, and Y-depleted extra layer formation. Consequently, the overdosed Ni weakens the passivation stability and corrosion resistance of the as-spun ribbon. The key role of the overdosed Ni can form a strong network and crystalline grain boundary in the amorphous matrix, which can transport Y and O to participate in the oxidation. These results can help us explore a valuable method for designing new Al-based metallic glasses. The Al95−xNixY5 ribbon x = 7 has a Y-depleted extra film and has a longer passive zone in the polarization curve and higher corrosion resistance than x = 10.![]()
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Affiliation(s)
- X. N. Wang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
| | - Y. Feng
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
| | - H. Z. Liu
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
| | - H. Zhang
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
| | - Z. C. Yan
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
| | - Y. W. Bai
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
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8
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Haroon K, Arafeh A, Cunliffe S, Martin P, Rodgers T, Mendoza Ć, Baker M. Comparison of Individual and Integrated Inline Raman, Near-Infrared, and Mid-Infrared Spectroscopic Models to Predict the Viscosity of Micellar Liquids. APPLIED SPECTROSCOPY 2020; 74:819-831. [PMID: 32312088 PMCID: PMC7750678 DOI: 10.1177/0003702820924043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 04/09/2020] [Indexed: 06/11/2023]
Abstract
In many industries, viscosity is an important quality parameter which significantly affects consumer satisfaction and process efficiency. In the personal care industry, this applies to products such as shampoo and shower gels whose complex structures are built up of micellar liquids. Measuring viscosity offline is well established using benchtop rheometers and viscometers. The difficulty lies in measuring this property directly in the process via on or inline technologies. Therefore, the aim of this work is to investigate whether proxy measurements using inline vibrational spectroscopy, e.g., near-infrared (NIR), mid-infrared (MIR), and Raman, can be used to predict the viscosity of micellar liquids. As optical techniques, they are nondestructive and easily implementable process analytical tools where each type of spectroscopy detects different molecular functionalities. Inline fiber optic coupled probes were employed; a transmission probe for NIR measurements, an attenuated total reflectance probe for MIR and a backscattering probe for Raman. Models were developed using forward interval partial least squares variable selection and log viscosity was used. For each technique, combinations of pre-processing techniques were trialed including detrending, Whittaker filters, standard normal variate, and multiple scatter correction. The results indicate that all three techniques could be applied individually to predict the viscosity of micellar liquids all showing comparable errors of prediction: NIR: 1.75 Pa s; MIR: 1.73 Pa s; and Raman: 1.57 Pa s. The Raman model showed the highest relative prediction deviation (RPD) value of 5.07, with the NIR and MIR models showing slightly lower values of 4.57 and 4.61, respectively. Data fusion was also explored to determine whether employing information from more than one data set improved the model quality. Trials involved weighting data sets based on their signal-to-noise ratio and weighting based on transmission curves (infrared data sets only). The signal-to-noise weighted NIR-MIR-Raman model showed the best performance compared with both combined and individual models with a root mean square error of cross-validation of 0.75 Pa s and an RPD of 10.62. This comparative study provides a good initial assessment of the three prospective process analytical technologies for the measurement of micellar liquid viscosity but also provides a good basis for general measurements of inline viscosity using commercially available process analytical technology. With these techniques typically being employed for compositional analysis, this work presents their capability in the measurement of viscosity-an important physical parameter, extending the applicability of these spectroscopic techniques.
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Affiliation(s)
- Kiran Haroon
- School of Chemical Engineering and
Analytical Science, The University of
Manchester, Manchester, UK
| | - Ali Arafeh
- School of Chemical Engineering and
Analytical Science, The University of
Manchester, Manchester, UK
| | - Stephanie Cunliffe
- School of Chemical Engineering and
Analytical Science, The University of
Manchester, Manchester, UK
| | - Philip Martin
- School of Chemical Engineering and
Analytical Science, The University of
Manchester, Manchester, UK
| | - Thomas Rodgers
- School of Chemical Engineering and
Analytical Science, The University of
Manchester, Manchester, UK
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9
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Hydrophobically associating polymers for enhanced oil recovery – Part B: A review of modelling approach to flow in porous media. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111495] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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10
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Sun Z, Kang Y, Kang Y. Density Functional Study on Enhancement of Modulus of Confined Fluid in Nanopores. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b02437] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zongli Sun
- Science and Technology College, North China Electric Power University, Baoding 071051, P. R. China
| | - Yanshuang Kang
- College of Science, Hebei Agricultural University, Baoding 071001, P. R. China
| | - Yanmei Kang
- University of International Relations, Beijing 100091, P. R. China
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11
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Ewen JP, Gao H, Müser MH, Dini D. Shear heating, flow, and friction of confined molecular fluids at high pressure. Phys Chem Chem Phys 2019; 21:5813-5823. [PMID: 30806390 DOI: 10.1039/c8cp07436d] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Understanding the molecular-scale behavior of fluids confined and sheared between solid surfaces is important for many applications, particularly tribology where this often governs the macroscopic frictional response. In this study, nonequilibrium molecular dynamics simulations are performed to investigate the effects of fluid and surface properties on the spatially resolved temperature and flow profiles, as well as friction. The severe pressure and shear rate conditions studied are representative of the elastohydrodynamic lubrication regime. In agreement with tribology experiments, flexible lubricant molecules give low friction, which increases linearly with logarithmic shear rate, while bulky traction fluids show higher friction, but a weaker shear rate dependence. Compared to lubricants, traction fluids show more significant shear heating and stronger shear localization. Models developed for macroscopic systems can be used to describe both the spatially resolved temperature profile shape and the mean film temperature rise. The thermal conductivity of the fluids increases with pressure and is significantly higher for lubricants compared to traction fluids, in agreement with experimental results. In a subset of simulations, the efficiency of the thermostat in one of the surfaces is reduced to represent surfaces with lower thermal conductivity. For these unsymmetrical systems, the flow and the temperature profiles become strongly asymmetric and some thermal slip can occur at the solid-fluid interface, despite the absence of velocity slip. The larger temperature rises and steeper velocity gradients in these cases lead to large reductions in friction, particularly at high pressure and shear rate.
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Affiliation(s)
- James P Ewen
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK.
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12
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Jeffreys S, di Mare L, Liu X, Morgan N, Wong JSS. Elastohydrodynamic lubricant flow with nanoparticle tracking. RSC Adv 2019; 9:1441-1450. [PMID: 35517995 PMCID: PMC9059655 DOI: 10.1039/c8ra09396b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 12/22/2018] [Indexed: 11/21/2022] Open
Abstract
Lubricants operating in elastohydrodynamic (EHD) contacts exhibit local variations in rheological properties when the contact pressure rises.
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Affiliation(s)
- S. Jeffreys
- Department of Mechanical Engineering
- Imperial College London
- UK
| | - L. di Mare
- Oxford Thermofluids Institute
- Department of Engineering Science
- St John's College
- University of Oxford
- UK
| | - X. Liu
- Department of Mechanical Engineering
- Imperial College London
- UK
| | - N. Morgan
- Department of Mechanical Engineering
- Imperial College London
- UK
- Shell Global Solutions UK Ltd
- Manchester M22 0RR
| | - J. S. S. Wong
- Department of Mechanical Engineering
- Imperial College London
- UK
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13
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Dench J, di Mare L, Morgan N, Wong JSS. Comparing the molecular and global rheology of a fluid under high pressures. Phys Chem Chem Phys 2018; 20:30267-30280. [PMID: 30483689 DOI: 10.1039/c8cp05155k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The viscosity of liquids is a strong function of pressure. While viscosity is relatively easy to measure at low pressure, high-pressure rheology presents significant experimental challenges. As a result, rheological models are often used to extrapolate viscosity from low pressure measurements to higher pressures. Techniques to obtain data over a wide range of pressures and shear rates, as well as understanding the validity and limitations of methods to fill the gaps in the available data, are therefore of crucial practical and theoretical importance. This work examines the viscosity of polyalphaolefin (PAO) by combining average global area averaged measurements at high pressure and local molecular viscosity measurements at moderate pressures. Viscosities spanning five orders of magnitude are examined at pressures up to 720 MPa. High pressure results were obtained with friction measurements where the fluid is sheared between two surfaces in a loaded point contact. The local molecular microviscosity at medium and low pressures was measured by applying a technique based on fluorescence anisotropy, which probes the rotational motion of dye molecules in a nanoscale film under shear. Both sets of measurements are taken in the same configuration, an elastohydrodynamic (EHD) contact. This is the first set of quantitative local viscosity measurements that have been verified against both friction and high pressure rheometry measurements. Commonly used rheological models were compared to experimental results. Our work shows that fluorescence anisotropy and friction measurements can be used to determine the viscosity of liquids over a wide range of conditions from a single experimental setup. The results obtained match results from low- and high-pressure rheometry for PAO. The importance of correcting friction data for pressure non-uniformity, temperature and shear thinning is also highlighted.
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Affiliation(s)
- J Dench
- Department of Mechanical Engineering, Imperial College London, SW7 2AZ, UK.
| | - L di Mare
- St. John's College, Oxford Thermofluids Institute, Department of Engineering Science, University of Oxford, Oxford OX2 0ES, UK
| | - N Morgan
- Department of Mechanical Engineering, Imperial College London, SW7 2AZ, UK. and Shell Global Solutions (UK) Ltd, Shell Centre, York Road, London, SE1 7NA, UK
| | - J S S Wong
- Department of Mechanical Engineering, Imperial College London, SW7 2AZ, UK.
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14
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Albahrani SMB, Seoudi T, Philippon D, Lafarge L, Reiss P, Hajjaji H, Guillot G, Querry M, Bluet JM, Vergne P. Quantum dots to probe temperature and pressure in highly confined liquids. RSC Adv 2018; 8:22897-22908. [PMID: 35540138 PMCID: PMC9081400 DOI: 10.1039/c8ra03652g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/15/2018] [Indexed: 11/22/2022] Open
Abstract
A new in situ technique for temperature and pressure measurement within dynamic thin-film flows of liquids is presented. The technique is based on the fluorescence emission sensitivity of CdSe/CdS/ZnS quantum dots to temperature and pressure variations. In this respect, the quantum dots were dispersed in squalane, and their emission energy dependence on temperature and pressure was calibrated under static conditions. Temperature calibration was established between 295 K and 393 K showing a temperature sensitivity of 0.32 meV K−1. Pressure calibration was, in turn, conducted up to 1.1 GPa using a diamond anvil cell, yielding a pressure sensitivity of 33.2 meV GPa−1. The potential of CdSe/CdS/ZnS quantum dots as sensors to probe temperature and pressure was proven by applying the in situ technique to thin films of liquids undergoing dynamic conditions. Namely, temperature rises have been measured in liquid films subjected to shear heating between two parallel plates in an optical rheometer. In addition, pressure rises have been measured in a lubricated point contact under pure rolling and isothermal conditions. In both cases, the measured values have been successfully compared with theoretical or numerical predictions. These comparisons allowed the validation of the new in situ technique and demonstrated the potential of the quantum dots for further mapping application in more complex and/or severe conditions. A new in situ technique using CdSe/CdS/ZnS quantum dots fluorescence to probe pressure and temperature within highly confined flows of liquids.![]()
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Affiliation(s)
| | | | | | | | - Peter Reiss
- Univ. Grenoble Alpes
- CEA
- CNRS
- INAC-SyMMES-STEP
- 38000 Grenoble
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15
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Zhou K, Ren M, Deng B, Lin W. Development of a viscosity sensitive fluorescent probe for real-time monitoring of mitochondria viscosity. NEW J CHEM 2017. [DOI: 10.1039/c7nj02270k] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Through rational design, two new mitochondria-targeted fluorescent viscosity probes were developed, which exhibited favorable properties such as large turn on fluorescence signal, good selectivity, low cytotoxicity, and high colocation coefficient (>0.90).
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Affiliation(s)
- Kai Zhou
- Institute of Fluorescent Probes for Biological Imaging, School of Chemistry and Chemical Engineering, School of Materials Science and Engineering, University of Jinan
- Jinan
- P. R. China
| | - Mingguang Ren
- Institute of Fluorescent Probes for Biological Imaging, School of Chemistry and Chemical Engineering, School of Materials Science and Engineering, University of Jinan
- Jinan
- P. R. China
| | - Beibei Deng
- Institute of Fluorescent Probes for Biological Imaging, School of Chemistry and Chemical Engineering, School of Materials Science and Engineering, University of Jinan
- Jinan
- P. R. China
| | - Weiying Lin
- Institute of Fluorescent Probes for Biological Imaging, School of Chemistry and Chemical Engineering, School of Materials Science and Engineering, University of Jinan
- Jinan
- P. R. China
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16
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Ewen JP, Gattinoni C, Zhang J, Heyes DM, Spikes HA, Dini D. On the effect of confined fluid molecular structure on nonequilibrium phase behaviour and friction. Phys Chem Chem Phys 2017; 19:17883-17894. [DOI: 10.1039/c7cp01895a] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Atomistic simulations and tribology experiments uncover the effect of molecular structure on the flow and friction behaviour of confined films under extreme conditions.
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Affiliation(s)
- J. P. Ewen
- Department of Mechanical Engineering
- Imperial College London
- London SW7 2AZ
- UK
| | - C. Gattinoni
- Department of Mechanical Engineering
- Imperial College London
- London SW7 2AZ
- UK
- Department of Materials
| | - J. Zhang
- Department of Mechanical Engineering
- Imperial College London
- London SW7 2AZ
- UK
| | - D. M. Heyes
- Department of Mechanical Engineering
- Imperial College London
- London SW7 2AZ
- UK
| | - H. A. Spikes
- Department of Mechanical Engineering
- Imperial College London
- London SW7 2AZ
- UK
| | - D. Dini
- Department of Mechanical Engineering
- Imperial College London
- London SW7 2AZ
- UK
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17
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Dench J, Morgan N, Wong JSS. Quantitative Viscosity Mapping Using Fluorescence Lifetime Measurements. TRIBOLOGY LETTERS 2016; 65:25. [PMID: 32355438 PMCID: PMC7175709 DOI: 10.1007/s11249-016-0807-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 12/18/2016] [Indexed: 06/11/2023]
Abstract
Lubricant viscosity is a key driver in both the tribological performance and energy efficiency of a lubricated contact. Elastohydrodynamic (EHD) lubrication produces very high pressures and shear rates, conditions hard to replicate using conventional rheometry. In situ rheological measurements within a typical contact are therefore important to investigate how a fluid behaves under such conditions. Molecular rotors provide such an opportunity to extract the local viscosity of a fluid under EHD lubrication. The validity of such an application is shown by comparing local viscosity measurements obtained using molecular rotors and fluorescence lifetime measurements, in a model EHD lubricant, with reference measurements using conventional rheometry techniques. The appropriateness of standard methods used in tribology for high-pressure rheometry (combining friction and film thickness measurements) has been verified when the flow of EHD lubricant is homogeneous and linear. A simple procedure for calibrating the fluorescence lifetime of molecular rotors at elevated pressure for viscosity measurements is proposed.
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Affiliation(s)
- J. Dench
- Department of Mechanical Engineering, Imperial College London, London, SW7 2AZ UK
| | - N. Morgan
- Department of Mechanical Engineering, Imperial College London, London, SW7 2AZ UK
- Shell Global Solutions (UK) Ltd, Brabazon House, Threapwood Road, Manchester, M22 0RR UK
| | - J. S. S. Wong
- Department of Mechanical Engineering, Imperial College London, London, SW7 2AZ UK
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18
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Maćkowiak S, Heyes DM, Dini D, Brańka AC. Non-equilibrium phase behavior and friction of confined molecular films under shear: A non-equilibrium molecular dynamics study. J Chem Phys 2016; 145:164704. [DOI: 10.1063/1.4965829] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Affiliation(s)
- Sz. Maćkowiak
- Institute of Physics, Poznań University of Technology, Piotrowo 3, 60-965 Poznań, Poland
| | - D. M. Heyes
- Department of Mechanical Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - D. Dini
- Department of Mechanical Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - A. C. Brańka
- Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland
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19
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Theoretical predictions of viscosity of methane under confined conditions. Chin J Chem Eng 2016. [DOI: 10.1016/j.cjche.2016.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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