1
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Arya V, Chaudhuri A, Bakli C. Wettability-modulated behavior of polymers under varying degrees of nano-confinement. J Chem Phys 2024; 160:064905. [PMID: 38341795 DOI: 10.1063/5.0185533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 01/15/2024] [Indexed: 02/13/2024] Open
Abstract
Extreme confinement in nanochannels results in unconventional equilibrium and flow behavior of polymers. The underlying flow physics dictating such paradigms remains far from being understood and more so if the confining substrate is composed of two-dimensional materials, such as graphene. In this study, we conducted systematic molecular dynamics simulations to explore the effect of wettability, confinement, and chain length on polymer flow through graphene-like nanochannels. Altering the wetting properties of these membranes that structurally represent graphene results in substantial changes in the behavior of polymers of disparate chain lengths. Longer hydrocarbon chains (n-dodecane) exhibit negligible wettability-dependent structuring in narrower nanochannels compared to shorter chains (n-hexane) culminating in higher average velocities and interfacial slippage of n-dodecane under less wettable conditions. We demonstrate that the wettability compensation comes from chain entanglement attributed to entropic factors. This study reveals a delicate balance between wettability-dependent enthalpy and chain-length-dependent entropy, resulting in a unique nanoscale flow paradigm, thus not only having far-reaching implications in the superior discernment of polymeric flow in sub-micrometer regimes but also potentially revolutionizing various applications in the oil industry, including innovative oil transport, oil extraction, ion transport polymers, and separation membranes.
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Affiliation(s)
- Vinay Arya
- Thermofluidics and Nanotechnology for Sustainable Energy Systems Laboratory, School of Energy Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Abhirup Chaudhuri
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Chirodeep Bakli
- Thermofluidics and Nanotechnology for Sustainable Energy Systems Laboratory, School of Energy Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
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2
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Stock S, von Klitzing R, Rahimzadeh A. Dynamic light scattering for particle characterization subjected to ultrasound: a study on compact particles and acousto-responsive microgels. Sci Rep 2024; 14:989. [PMID: 38200144 PMCID: PMC10781767 DOI: 10.1038/s41598-024-51404-0] [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: 09/12/2023] [Accepted: 01/04/2024] [Indexed: 01/12/2024] Open
Abstract
In this report, we investigate dynamic light scattering (DLS) from both randomly diffusing silica particles and acousto-responsive microgels in aqueous dispersions under ultrasonic vibration. Employing high-frequency ultrasound (US) with low amplitude ensures that the polymers remain intact without damage. We derive theoretical expressions for the homodyne autocorrelation function, incorporating the US term alongside the diffusion term. Subsequently, we successfully combined US with a conventional DLS system to experimentally characterize compact silica particles and microgels under the influence of US. Our model allows us to extract essential parameters, including particle size, frequency, and amplitude of particle vibration, based on the correlation function of the scattered light intensity. The studies involving non-responsive silica particles demonstrate that the US does not disrupt size determination, establishing them as suitable reference systems. In addition, we could be able to experimentally resolve the µs-order motion of particles for the first time. Microgels subjected to the US show the same swelling/shrinking behavior as that induced by temperature but with significantly faster kinetics. The findings of this study have potential applications in various industrial and biomedical fields such as smart coatings and drug delivery that benefit from the characterization of macromolecules subjected to the US. Furthermore, the current work may lead to characterizing the mechanical properties of soft particles based on their vibration amplitude extracted using this method.
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Affiliation(s)
- Sebastian Stock
- Soft Matter at Interfaces, Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstraße 8, 64289, Darmstadt, Germany
| | - Regine von Klitzing
- Soft Matter at Interfaces, Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstraße 8, 64289, Darmstadt, Germany
| | - Amin Rahimzadeh
- Soft Matter at Interfaces, Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstraße 8, 64289, Darmstadt, Germany.
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3
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Peng H, Liu H, Voigtmann T. Nonmonotonic Dynamical Correlations beneath the Surface of Glass-Forming Liquids. PHYSICAL REVIEW LETTERS 2022; 129:215501. [PMID: 36461957 DOI: 10.1103/physrevlett.129.215501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 12/20/2021] [Accepted: 10/27/2022] [Indexed: 06/17/2023]
Abstract
Collective motion over increasing length scales is a signature of the vitrification process of liquids. We demonstrate how distinct static and dynamic length scales govern the dynamics of vitrifying films. In contrast to a monotonically growing static correlation length, the dynamical correlation length that measures the extent of surface-dynamics acceleration into the bulk displays a striking nonmonotonic temperature evolution that is robust also against changes in detailed interatomic interaction. This nonmonotonic change defines a crossover temperature T_{*} that is distinct from the critical temperature T_{c} of mode-coupling theory. We connect this nonmonotonic change to a morphological change of cooperative rearrangement regions of fast particles, and to the point where the decoupling of fast-particle motion from the bulk relaxation is most sensitive to fluctuations. We propose a rigorous definition of this new crossover temperature T_{*} within a recent extension of mode-coupling theory, the stochastic β-relaxation theory.
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Affiliation(s)
- Hailong Peng
- School of Materials Science and Engineering, Central South University, 932 South Lushan Rd, 410083 Changsha, China
| | - Huashan Liu
- School of Materials Science and Engineering, Central South University, 932 South Lushan Rd, 410083 Changsha, China
| | - Thomas Voigtmann
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
- Department of Physics, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
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4
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Douglass IM, Dyre JC. Distance-as-time in physical aging. Phys Rev E 2022; 106:054615. [PMID: 36559484 DOI: 10.1103/physreve.106.054615] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 11/05/2022] [Indexed: 06/17/2023]
Abstract
Although it has been known for half a century that the physical aging of glasses in experiments is described well by a linear thermal-history convolution integral over the so-called material time, the microscopic definition and interpretation of the material time remains a mystery. We propose that the material-time increase over a given time interval reflects the distance traveled by the system's particles. Different possible distance measures are discussed, starting from the standard mean-square displacement and its inherent-state version that excludes the vibrational contribution. The viewpoint adopted, which is inspired by and closely related to pioneering works of Cugliandolo and Kurchan from the 1990s, implies a "geometric reversibility" and a "unique-triangle property" characterizing the system's path in configuration space during aging. Both of these properties are inherited from equilibrium, and they are here confirmed by computer simulations of an aging binary Lennard-Jones system. Our simulations moreover show that the slow particles control the material time. This motivates a "dynamic-rigidity-percolation" picture of physical aging. The numerical data show that the material time is dominated by the slowest particles' inherent mean-square displacement, which is conveniently quantified by the inherent harmonic mean-square displacement. This distance measure collapses data for potential-energy aging well in the sense that the normalized relaxation functions following different temperature jumps are almost the same function of the material time. Finally, the standard Tool-Narayanaswamy linear material-time convolution-integral description of physical aging is derived from the assumption that when time is replaced by distance in the above sense, an aging system is described by the same expression as that of linear-response theory.
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Affiliation(s)
- Ian M Douglass
- Glass and Time, IMFUFA, Department of Science and Environment, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark
| | - Jeppe C Dyre
- Glass and Time, IMFUFA, Department of Science and Environment, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark
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5
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Kaffashnia A, Evstigneev M. Scaling and universality in Brownian motion on a stochastic harmonic oscillator chain. Phys Rev E 2022; 105:064134. [PMID: 35854516 DOI: 10.1103/physreve.105.064134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 06/15/2022] [Indexed: 11/07/2022]
Abstract
Diffusion of a Brownian particle along a stochastic harmonic oscillator chain is investigated. In contrast to the usually discussed Brownian motion driven by Gaussian white noise, the particle at high temperatures performs long Lévy flights. At high temperatures T the diffusion coefficient scales as D∼T^{2+α}, where the parameter α determine the average damping force ∝1/(T^{α}P) on the particle at large momentum P and at high temperature. The exponent α depends on the particle-chain interaction and chain properties. It is shown that the mean time t[over ¯]_{f} necessary to perform a flight of l lattice constant scales with l as t[over ¯]_{f}∝l^{2/3} at high temperatures and flight lengths. Last, the flight length probability distribution is found to decay as 1/l^{β} with the exponent β=4/3 being universal, i.e., independent of the model parameters.
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Affiliation(s)
- Amir Kaffashnia
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, A1B 3X7 Canada
| | - Mykhaylo Evstigneev
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, A1B 3X7 Canada
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6
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Rauber D, Philippi F, Kuttich B, Becker J, Kraus T, Hunt P, Welton T, Hempelmann R, Kay CWM. Curled cation structures accelerate the dynamics of ionic liquids. Phys Chem Chem Phys 2021; 23:21042-21064. [PMID: 34522943 DOI: 10.1039/d1cp02889h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ionic liquids are modern liquid materials with potential and actual implementation in many advanced technologies. They combine many favourable and modifiable properties but have a major inherent drawback compared to molecular liquids - slower dynamics. In previous studies we found that the dynamics of ionic liquids are significantly accelerated by the introduction of multiple ether side chains into the cations. However, the origin of the improved transport properties, whether as a result of the altered cation conformation or due to the absence of nanostructuring within the liquid as a result of the higher polarity of the ether chains, remained to be clarified. Therefore, we prepared two novel sets of methylammonium based ionic liquids; one set with three ether substituents and another set with three butyl side chains, in order to compare their dynamic properties and liquid structures. Using a range of anions, we show that the dynamics of the ether-substituted cations are systematically and distinctly accelerated. Liquefaction temperatures are lowered and fragilities increased, while at the same time cation-anion distances are slightly larger for the alkylated samples. Furthermore, pronounced liquid nanostructures were not observed. Molecular dynamics simulations demonstrate that the origin of the altered properties of the ether substituted ionic liquids is primarily due to a curled ether chain conformation, in contrast to the alkylated cations where the alkyl chains retain a linear conformation. Thus, the observed structure-property relations can be explained by changes in the geometric shape of the cations, rather than by the absence of a liquid nanostructure. Application of quantum chemical calculations to a simplified model system revealed that intramolecular hydrogen-bonding is responsible for approximately half of the stabilisation of the curled ether-cations, whereas the other half stems from non-specific long-range interactions. These findings give more detailed insights into the structure-property relations of ionic liquids and will guide the development of ionic liquids that do not suffer from slow dynamics.
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Affiliation(s)
- Daniel Rauber
- Department of Chemistry, Saarland University, Campus B2.2, 66123, Saarbrücken, Germany.
| | - Frederik Philippi
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, London W12 0BZ, UK
| | - Björn Kuttich
- INM-Leibniz Institute for New Materials, Campus D2.2, 66123, Saarbrücken, Germany
| | - Julian Becker
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, London W12 0BZ, UK
| | - Tobias Kraus
- Department of Chemistry, Saarland University, Campus B2.2, 66123, Saarbrücken, Germany. .,INM-Leibniz Institute for New Materials, Campus D2.2, 66123, Saarbrücken, Germany
| | - Patricia Hunt
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, London W12 0BZ, UK.,School of Chemical and Physical Sciences, Victoria University of Wellington, New Zealand
| | - Tom Welton
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, London W12 0BZ, UK
| | - Rolf Hempelmann
- Department of Chemistry, Saarland University, Campus B2.2, 66123, Saarbrücken, Germany.
| | - Christopher W M Kay
- Department of Chemistry, Saarland University, Campus B2.2, 66123, Saarbrücken, Germany. .,London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AH, UK.
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7
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Cao QL, Wang PP, Huang DH. Revisiting the Stokes-Einstein relation for glass-forming melts. Phys Chem Chem Phys 2020; 22:2557-2565. [PMID: 31942907 DOI: 10.1039/c9cp04984c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Molecular dynamics simulations of Ni36Zr64, Cu65Zr35 and Ni80Al20 were carried out over a broad range of temperature (900-3000 K) to investigate the Stokes-Einstein (SE) relation for glass-forming melts. Our results reproduce experimental structural and transport properties. Results show that the breakdown temperature of the SE relation (TSE) equals the dynamical crossover temperature (TA) and both are roughly twice the glass-transition temperature (Tg) for the three glass-forming melts (TSE = TA ≈ 2.0Tg). The product of the individual component self-diffusion coefficient and viscosity Dαη can be roughly regarded as a constant at the transition zone (a small temperature range around TSE) in which the temperature behaviors of self-diffusion coefficient and viscosity switch from high-temperature Arrhenius to a low-temperature VFT behavior. Below TSE, the decoupling of component diffusion coefficients was found. In particular, the decoupling of component diffusion coefficients can be ascribed to the decoupling of the partial pair structural correlation of components, which can be clearly reflected by the intersection of the high-temperature and low-temperature behaviors of the ratio between the partial pair correlation entropy of components (Sβ2/Sα2). Furthermore, the ratio between the partial pair correlation entropy of components may be used to predict the validity of the SE relation, in the absence of both transport coefficients and atomic coordinates.
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Affiliation(s)
- Qi-Long Cao
- Key Laboratory of Computational Physics, Yibin University, Yibin 644007, P. R. China.
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8
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Corsaro C, Fazio E, Mallamace D. The Stokes-Einstein relation in water/methanol solutions. J Chem Phys 2019; 150:234506. [DOI: 10.1063/1.5096760] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- C. Corsaro
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università di Messina, Viale F. Stagno d’ Alcontres, 31, 98166 Messina, Italy
| | - E. Fazio
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università di Messina, Viale F. Stagno d’ Alcontres, 31, 98166 Messina, Italy
| | - D. Mallamace
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università di Messina, Viale F. Stagno d’ Alcontres, 31, 98166 Messina, Italy
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9
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Parmar ADS, Sengupta S, Sastry S. Power law relationship between diffusion coefficients in multi-component glass forming liquids. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2018; 41:90. [PMID: 30078172 DOI: 10.1140/epje/i2018-11702-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 07/13/2018] [Indexed: 06/08/2023]
Abstract
The slow down of dynamics in glass forming liquids as the glass transition is approached has been characterised through the Adam-Gibbs relation, which relates relaxation time scales to the configurational entropy. The Adam-Gibbs relation cannot apply simultaneously to all relaxation times scales unless they are coupled, and exhibit closely related temperature dependences. The breakdown of the Stokes-Einstein relation presents an interesting situation to the contrary, and in analysing it, it has recently been shown that the Adam-Gibbs relation applies to diffusion coefficients rather than to viscosity or structural relaxation times related to the decay of density fluctuations. However, for multi-component liquids --the typical cases considered in computer simulations, metallic glass formers, etc.-- such a statement raises the question of which diffusion coefficient is described by the Adam-Gibbs relation. All diffusion coefficients can be consistently described by the Adam-Gibbs relation if they bear a power law relationship with each other. Remarkably, we find that for a wide range of glass formers, and for a wide range of temperatures spanning the normal and the slow relaxation regimes, such a relationship holds. We briefly discuss possible rationalisations of the observed behaviour.
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Affiliation(s)
- Anshul D S Parmar
- Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur Campus, 560064, Bengaluru, India
- Tata Institute of Fundamental Research, 500107, Hyderabad, Ranga Reddy District, India
| | - Shiladitya Sengupta
- Department of Fundamental Engineering, Institute of Industrial Science, The University of Tokyo, Komaba 4-6-1, 153-8505, Meguro-ku, Tokyo, Japan
| | - Srikanth Sastry
- Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur Campus, 560064, Bengaluru, India.
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10
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Nucleoprotein from the unique human infecting Orthobunyavirus of Simbu serogroup (Oropouche virus) forms higher order oligomers in complex with nucleic acids in vitro. Amino Acids 2018; 50:711-721. [PMID: 29626301 DOI: 10.1007/s00726-018-2560-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 03/26/2018] [Indexed: 10/17/2022]
Abstract
Oropouche virus (OROV) is the unique known human pathogen belonging to serogroup Simbu of Orthobunyavirus genus and Bunyaviridae family. OROV is transmitted by wild mosquitoes species to sloths, rodents, monkeys and birds in sylvatic environment, and by midges (Culicoides paraensis and Culex quinquefasciatus) to man causing explosive outbreaks in urban locations. OROV infection causes dengue fever-like symptoms and in few cases, can cause clinical symptoms of aseptic meningitis. OROV contains a tripartite negative RNA genome encapsidated by the viral nucleocapsid protein (NP), which is essential for viral genome encapsidation, transcription and replication. Here, we reported the first study on the structural properties of a recombinant NP from human pathogen Oropouche virus (OROV-rNP). OROV-rNP was successfully expressed in E. coli in soluble form and purified using affinity and size-exclusion chromatographies. Purified OROV-rNP was analyzed using a series of biophysical tools and molecular modeling. The results showed that OROV-rNP formed stable oligomers in solution coupled with endogenous E. coli nucleic acids (RNA) of different sizes. Finally, electron microscopy revealed a total of eleven OROV-rNP oligomer classes with tetramers (42%) and pentamers (43%) the two main populations and minor amounts of other bigger oligomeric states, such as hexamers, heptamers or octamers. The different RNA sizes and nucleotide composition may explain the diversity of oligomer classes observed. Besides, structural differences among bunyaviruses NP can be used to help in the development of tools for specific diagnosis and epidemiological studies of this group of viruses.
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11
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Abstract
The highly viscous flow is due to thermally activated Eshelby transitions which transform a region of the undercooled liquid to a different structure with a different elastic misfit to the viscoelastic surroundings. A self-consistent determination of the viscosity in this picture explains why the average structural relaxation time is a factor of eight longer than the Maxwell time. The physical reason for the short Maxwell time is the very large contribution of strongly strained inherent states to the fluidity (the inverse viscosity). At the Maxwell time, the viscous no-return processes coexist with the back-and-forth jumping retardation processes.
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Affiliation(s)
- U Buchenau
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1) and Institute for Complex Systems (ICS-1), 52425 Jülich, Germany
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12
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Lee HB, Cong A, Leopold H, Currie M, Boersma AJ, Sheets ED, Heikal AA. Rotational and translational diffusion of size-dependent fluorescent probes in homogeneous and heterogeneous environments. Phys Chem Chem Phys 2018; 20:24045-24057. [DOI: 10.1039/c8cp03873b] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Macromolecular crowding effects on diffusion depend on the fluorophore structure, the concentration of crowding agents, and the technique employed.
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Affiliation(s)
- Hong Bok Lee
- Department of Chemistry and Biochemistry
- Swenson College of Science and Engineering
- University of Minnesota Duluth
- Duluth
- USA
| | - Anh Cong
- Department of Chemistry and Biochemistry
- Swenson College of Science and Engineering
- University of Minnesota Duluth
- Duluth
- USA
| | - Hannah Leopold
- Department of Chemistry and Biochemistry
- Swenson College of Science and Engineering
- University of Minnesota Duluth
- Duluth
- USA
| | - Megan Currie
- Department of Chemistry and Biochemistry
- Swenson College of Science and Engineering
- University of Minnesota Duluth
- Duluth
- USA
| | | | - Erin D. Sheets
- Department of Chemistry and Biochemistry
- Swenson College of Science and Engineering
- University of Minnesota Duluth
- Duluth
- USA
| | - Ahmed A. Heikal
- Department of Chemistry and Biochemistry
- Swenson College of Science and Engineering
- University of Minnesota Duluth
- Duluth
- USA
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13
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Parmar ADS, Sengupta S, Sastry S. Length-Scale Dependence of the Stokes-Einstein and Adam-Gibbs Relations in Model Glass Formers. PHYSICAL REVIEW LETTERS 2017; 119:056001. [PMID: 28949755 DOI: 10.1103/physrevlett.119.056001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Indexed: 05/23/2023]
Abstract
The Adam-Gibbs (AG) relation connects the dynamics of a glass-forming liquid to its thermodynamics via the configurational entropy and is of fundamental importance in descriptions of glassy behavior. The breakdown of the Stokes-Einstein relation (SEB) between the diffusion coefficient and the viscosity (or structural relaxation times) in glass formers raises the question as to which dynamical quantity the AG relation describes. By performing molecular dynamics simulations, we show that the AG relation is valid over the widest temperature range for the diffusion coefficient and not for the viscosity or relaxation times. Studying relaxation times defined at a given wavelength, we find that SEB and the deviation from the AG relation occur below a temperature at which the correlation length of dynamical heterogeneity equals the wavelength probed.
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Affiliation(s)
- Anshul D S Parmar
- Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
- TIFR Center for Interdisciplinary Sciences, 21 Brundavan Colony, Narsingi, Hyderabad 500075, India
| | - Shiladitya Sengupta
- Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
- Department of Fundamental Engineering, Institute of Industrial Science, The University of Tokyo, Komaba 4-6-1, Meguro-ku, Tokyo 153-8505, Japan
| | - Srikanth Sastry
- Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
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14
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Obukhovsky VV, Kutsyk AM, Nikonova VV, Ilchenko OO. Nonlinear diffusion in multicomponent liquid solutions. Phys Rev E 2017; 95:022133. [PMID: 28297985 DOI: 10.1103/physreve.95.022133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Indexed: 11/07/2022]
Abstract
Mutual diffusion in multicomponent liquids is studied. It is taken into consideration that the influence of complex formation on the diffusion process may be substantial. The theory is applied to analyze mass transfer in an acetone-chloroform solution. The molecular complex concentration was obtained from the analysis of Fourier transform infrared spectra of this solution. Taking into account molecular complex formation allows one to explain the experimental dependence of diffusion coefficients on the composition (components concentration). The accuracy of experimental and theoretical data descriptions in the frame of our model is compared to the accuracy for some other approaches.
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Affiliation(s)
| | - Andrii M Kutsyk
- Taras Shevchenko National University of Kiev, 01601 Kiev, Ukraine
| | | | - Oleksii O Ilchenko
- D. F. Chebotaryov Institute for Gerontology, National Academy of Medical Sciences of Ukraine, 04114 Kyiv, Ukraine
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15
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Ropo M, Akola J, Jones RO. Collective excitations and viscosity in liquid Bi. J Chem Phys 2016; 145:184502. [DOI: 10.1063/1.4965429] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Matti Ropo
- Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland
- COMP Centre of Excellence, Department of Applied Physics, Aalto University, FI-00076 Aalto, Finland
| | - Jaakko Akola
- Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland
- COMP Centre of Excellence, Department of Applied Physics, Aalto University, FI-00076 Aalto, Finland
| | - R. O. Jones
- Peter-Grünberg-Institut (PGI-1) and JARA/HPC, Forschungszentrum Jülich, D-52425 Jülich, Germany
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16
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Peng HL, Voigtmann T. Decoupled length scales for diffusivity and viscosity in glass-forming liquids. Phys Rev E 2016; 94:042612. [PMID: 27841604 DOI: 10.1103/physreve.94.042612] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Indexed: 06/06/2023]
Abstract
The growth of the characteristic length scales both for diffusion and viscosity is investigated by molecular dynamics utilizing the finite-size effect in a binary Lennard-Jones mixture. For those quantities relevant to the diffusion process (e.g., the hydrodynamic value and the spatial correlation function), a strong system-size dependence is found. In contrast, it is weak or absent for the shear relaxation process. Correlation lengths are estimated from the decay of the spatial correlation functions. We find the length scale for viscosity decouples from the one of diffusivity, featured by a saturated length even in high supercooling. This temperature-independent behavior of the length scale is reminiscent of the unapparent structure change upon supercooling, implying the manifestation of configuration entropy. Whereas for the diffusion process, it is manifested by relaxation dynamics and dynamic heterogeneity. The Stokes-Einstein relation is found to break down at the temperature where the decoupling of these lengths happens.
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Affiliation(s)
- H L Peng
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
| | - Th Voigtmann
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
- Department of Physics, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
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