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Hafner A, Gutfreund P, Toperverg BP, Geoghegan M, Sferrazza M. 2D reflectometry for the investigation of polymer interfaces: off-specular neutron scattering. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:364002. [PMID: 34253693 DOI: 10.1088/1361-648x/ac0282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 05/18/2021] [Indexed: 06/13/2023]
Abstract
Specular and off-specular neutron reflectometry have been used in a combined approach to study thin polymer films. Our goal in this work is to illustrate the power of the off-specular scattering technique to probe the properties of the buried interface of immiscible polymer bilayers of deuterated polystyrene and protonated poly(methyl methacrylate) (h-PMMA). The diffuse scattering stemming from these systems is discussed in relation to thermal fluctuations at the polymer/polymer interface, providing a means to extract in-plane correlation lengths from buried interfaces. In addition the onset of hole formation in the top layer is evidenced by the diffuse scattering, not easily detectable by specular reflection alone.
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Affiliation(s)
- Aljoša Hafner
- Institut Laue - Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble, Cedex 9, France
- Université Libre de Bruxelles, Département de Physique, 1050 Brussels, Belgium
| | - Philipp Gutfreund
- Institut Laue - Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble, Cedex 9, France
| | - Boris P Toperverg
- Institut Laue - Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble, Cedex 9, France
- Petersburg Nuclear Physics Institute, National Research Center 'Kurchatov Institute',188300 Gatchina, Russia
| | - Mark Geoghegan
- Department of Physics and Astronomy, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, United Kingdom
| | - Michele Sferrazza
- Université Libre de Bruxelles, Département de Physique, 1050 Brussels, Belgium
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2
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Yang F, Presto D, Pan Y, Liu K, Zhou L, Narayanan S, Zhu Y, Peng Z, Soucek MD, Tsige M, Foster MD. Proximity to Graphene Dramatically Alters Polymer Dynamics. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00317] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
| | | | | | | | | | - Suresh Narayanan
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
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3
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He Q, Narayanan S, Wu DT, Foster MD. Confinement Effects with Molten Thin Cyclic Polystyrene Films. ACS Macro Lett 2016; 5:999-1003. [PMID: 35614649 DOI: 10.1021/acsmacrolett.6b00497] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The surface fluctuations of a melt film of a low molecular weight cyclic polystyrene (CPS) manifest confinement effects for a film thickness (14Rg) much larger than that for which a melt film of the linear chain analog manifests confinement. This is true both in terms of absolute thickness and thickness relative to chain size, Rg. In fact, the linear analog polymer does not manifest confinement effects even at a thickness of 7Rg. Both types of films have a strongly adsorbed layer at the substrate that plays a role in slowing the surface fluctuations for the thinnest films. This layer is 70% thicker for the cyclic chains than for the linear chains. At the interface with the substrate the packing of the cyclic chains is perturbed much more strongly than is the packing of the linear chains.
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Affiliation(s)
- Qiming He
- Department
of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
| | - Suresh Narayanan
- X-ray
Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - David T. Wu
- Chemical
Engineering and Chemistry Departments, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Mark D. Foster
- Department
of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
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4
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James D, Higgins AM, Rees P, Geoghegan M, Brown MR, Chang SS, Môn D, Cubitt R, Dalgliesh R, Gutfreund P. Measurement of molecular mixing at a conjugated polymer interface by specular and off-specular neutron scattering. SOFT MATTER 2015; 11:9393-9403. [PMID: 26439643 DOI: 10.1039/c5sm02008e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Measurements have been performed on thermally equilibrated conjugated-polymer/insulating-polymer bilayers, using specular and off-specular neutron reflectivity. While specular reflectivity is only sensitive to the structure normal to the sample, off-specular measurements can probe the structure of the buried polymer/polymer interface in the plane of the sample. Systematic analysis of the scattering from a set of samples with varying insulating-polymer-thickness, using the distorted-wave Born approximation (DWBA), has allowed a robust determination of the intrinsic width at the buried polymer/polymer interface. The quantification of this width (12 Å ± 4 Å) allows us to examine aspects of the conjugated polymer conformation at the interface, by appealing to self-consistent field theory (SCFT) predictions for equilibrium polymer/polymer interfaces in the cases of flexible and semi-flexible chains. This analysis enables us to infer that mixing at this particular interface cannot be described in terms of polymer chain segments that adopt conformations similar to a random walk. Instead, a more plausible explanation is that the conjugated polymer chain segments become significantly oriented in the plane of the interface. It is important to point out that we are only able to reach this conclusion following the extensive analysis of reflectivity data, followed by comparison with SCFT predictions. It is not simply the case that conjugated polymers would be expected to adopt this kind of oriented conformation at the interface, because of their relatively high chain stiffness. It is the combination of a high stiffness and a relatively narrow intrinsic interfacial width that results in a deviation from flexible chain behaviour.
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Affiliation(s)
- David James
- College of Engineering, Swansea University, Fabian Way, Crymlyn Burrows, Swansea, SA1 8EN, Wales, UK.
| | - Anthony M Higgins
- College of Engineering, Swansea University, Fabian Way, Crymlyn Burrows, Swansea, SA1 8EN, Wales, UK.
| | - Paul Rees
- College of Engineering, Swansea University, Fabian Way, Crymlyn Burrows, Swansea, SA1 8EN, Wales, UK.
| | - Mark Geoghegan
- Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield, S3 7RH, UK
| | - M Rowan Brown
- College of Engineering, Swansea University, Fabian Way, Crymlyn Burrows, Swansea, SA1 8EN, Wales, UK.
| | - Shion-Seng Chang
- College of Engineering, Swansea University, Fabian Way, Crymlyn Burrows, Swansea, SA1 8EN, Wales, UK.
| | - Dyfrig Môn
- College of Engineering, Swansea University, Fabian Way, Crymlyn Burrows, Swansea, SA1 8EN, Wales, UK.
| | - Robert Cubitt
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Robert Dalgliesh
- ISIS, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, OX11 OQX, UK
| | - Philipp Gutfreund
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
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5
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Wang SF, Jiang Z, Narayanan S, Foster MD. Dynamics of Surface Fluctuations on Macrocyclic Melts. Macromolecules 2012. [DOI: 10.1021/ma2028215] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Shih-Fan Wang
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325, United
States
| | - Zhang Jiang
- X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439,
United States
| | - Suresh Narayanan
- X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439,
United States
| | - Mark D. Foster
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325, United
States
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6
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Affiliation(s)
- Yoshihisa Fujii
- Department of Physics, Boston University, Boston, Massachusetts 02215
| | - Zhaohui Yang
- Department of Physics, Boston University, Boston, Massachusetts 02215
| | - Andrew Clough
- Department of Physics, Boston University, Boston, Massachusetts 02215
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Willis AM, Freund JB. Enhanced droplet spreading due to thermal fluctuations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:464128. [PMID: 21715892 DOI: 10.1088/0953-8984/21/46/464128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The lubrication equation that governs the dynamics of thin liquid films can be augmented to account for stochastic stresses associated with the thermal fluctuations of the fluid. It has been suggested that under certain conditions the spreading rate of a liquid drop on a surface will be increased by these stochastic stresses. Here, an atomistic simulation of a spreading drop is designed to examine such a regime and provide a quantitative assessment of the stochastic lubrication equation for spreading. It is found that the atomistic drop does indeed spread faster than the standard lubrication equations would suggest and that the stochastic lubrication equation of Grün et al (2006 J. Stat. Phys. 122 1261-91) predicts the spread rate.
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Affiliation(s)
- A M Willis
- Department of Mechanical Science and Engineering, College of Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801, USA. College of Medicine at Urbana-Champaign, University of Illinois at Urbana-Champaign, USA
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8
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Yang ZH, Wang YJ, Todorova L, Tsui OKC. Examination of Nonliquidlike Behaviors in Molten Polymer Films. Macromolecules 2008. [DOI: 10.1021/ma801749a] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zhao H. Yang
- Department of Physics, Boston University, Boston, Massachusetts 02215, and Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Yong J. Wang
- Department of Physics, Boston University, Boston, Massachusetts 02215, and Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Lela Todorova
- Department of Physics, Boston University, Boston, Massachusetts 02215, and Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Ophelia K. C. Tsui
- Department of Physics, Boston University, Boston, Massachusetts 02215, and Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
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9
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Akgun B, Lee DR, Kim H, Zhang H, Prucker O, Wang J, Rühe J, Foster MD. Self-Affine Surfaces of Polymer Brushes. Macromolecules 2007. [DOI: 10.1021/ma0708794] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bulent Akgun
- Maurice Morton Institute of Polymer Science, University of Akron, Akron, Ohio 44325; X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439; and Department for Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
| | - Dong Ryeol Lee
- Maurice Morton Institute of Polymer Science, University of Akron, Akron, Ohio 44325; X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439; and Department for Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
| | - Hyeonjae Kim
- Maurice Morton Institute of Polymer Science, University of Akron, Akron, Ohio 44325; X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439; and Department for Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
| | - Haining Zhang
- Maurice Morton Institute of Polymer Science, University of Akron, Akron, Ohio 44325; X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439; and Department for Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
| | - Oswald Prucker
- Maurice Morton Institute of Polymer Science, University of Akron, Akron, Ohio 44325; X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439; and Department for Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
| | - Jin Wang
- Maurice Morton Institute of Polymer Science, University of Akron, Akron, Ohio 44325; X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439; and Department for Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
| | - Jürgen Rühe
- Maurice Morton Institute of Polymer Science, University of Akron, Akron, Ohio 44325; X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439; and Department for Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
| | - Mark D. Foster
- Maurice Morton Institute of Polymer Science, University of Akron, Akron, Ohio 44325; X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439; and Department for Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
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10
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Jiang Z, Kim H, Jiao X, Lee H, Lee YJ, Byun Y, Song S, Eom D, Li C, Rafailovich MH, Lurio LB, Sinha SK. Evidence for viscoelastic effects in surface capillary waves of molten polymer films. PHYSICAL REVIEW LETTERS 2007; 98:227801. [PMID: 17677879 DOI: 10.1103/physrevlett.98.227801] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Indexed: 05/16/2023]
Abstract
The surface dynamics of supported ultrathin polystyrene films with thickness comparable to the radius of gyration were investigated by surface sensitive x-ray photon correlation spectroscopy. We show for the first time that the conventional model of capillary waves on a viscous liquid has to be modified to include the effects of a shear modulus in order to explain both static and dynamic scattering data from ultrathin molten polymer films.
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Affiliation(s)
- Zhang Jiang
- Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
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11
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Bae SC, Granick S. Molecular Motion at Soft and Hard Interfaces: From Phospholipid Bilayers to Polymers and Lubricants. Annu Rev Phys Chem 2007; 58:353-74. [PMID: 17090226 DOI: 10.1146/annurev.physchem.58.032806.104527] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Spatially resolved and time-resolved understanding of complex fluid situations compose a new frontier in physical chemistry. Here we draw attention to the significance of spatially resolving systems whose ensemble average differs fundamentally from the spatially resolved individual elements. We take examples from the field of fluid phospholipid bilayers, to which macromolecules adsorb; the field of polymer physics, when flexible chains adsorb to the solid-liquid interface; and from the field of lubrication, when two solids are squeezed close together with confined fluid retained between them.
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Affiliation(s)
- Sung Chul Bae
- Department of Materials Science and Engineering, University of Illinois, Urbana, IL 61801, USA.
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12
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Fukuto M, Gang O, Alvine KJ, Pershan PS. Capillary wave fluctuations and intrinsic widths of coupled fluid-fluid interfaces: an x-ray scattering study of a wetting film on bulk liquid. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:031607. [PMID: 17025643 DOI: 10.1103/physreve.74.031607] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2006] [Revised: 07/25/2006] [Indexed: 05/12/2023]
Abstract
An x-ray specular reflectivity (XR) and off-specular diffuse scattering (XDS) study of the coupled thermal capillary fluctuations and the intrinsic profiles of two interacting fluid-fluid interfaces is presented. The measurements are carried out on complete wetting films of perfluoromethylcyclohexane (PFMC) on the surface of bulk liquid eicosane (C20), as a function of film thickness 30<D<160 A. In order to facilitate the analysis and interpretation of the data with minimal complexity, approximate methods for calculating scattering intensities are developed to take into account the subtleties of thermal diffuse scattering from layered liquid surfaces. With these methods, the calculations of XR/XDS intensities are reduced to a single numerical integration of simple functions in real space. In addition, an analytic expression is derived for small-angle XR that contains Debye-Waller-like factors with effective capillary roughness and takes into account the partial correlations of the two interfaces. The expression for the XR is quantitatively accurate so long as the reflection angle is small enough that the scattering from interfaces is distinguishable from bulk scattering. The results of the XR and XDS data analysis indicate that the capillary fluctuations at the two interfaces of the wetting films are partially correlated and their coupling is consistent with the van der Waals interactions. The relatively large intrinsic width (4 approximately 6A) of the liquid-liquid interface observed for thicker films (D greater than or similar to 50 A) is comparable to the value expected for the bulk liquid-liquid interface (D-->infinity), determined by either the radius of gyration (5.3 A) or the bulk correlation length (4.8 A) of the alkane C20. The intrinsic liquid-vapor interfacial width is sharper (approximately 2 A) and remains essentially constant over the entire probed range of D .
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Affiliation(s)
- Masafumi Fukuto
- Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
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Hu X, Jiang Z, Narayanan S, Jiao X, Sandy AR, Sinha SK, Lurio LB, Lal J. Observation of a low-viscosity interface between immiscible polymer layers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:010602. [PMID: 16907050 DOI: 10.1103/physreve.74.010602] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Revised: 06/07/2006] [Indexed: 05/11/2023]
Abstract
X-ray photon correlation spectroscopy was employed in a surface standing wave geometry in order to resolve the thermally driven in-plane dynamics at both the surface/vacuum (top) and polymer/polymer (bottom) interfaces of a thin polystyrene (PS) film on top of Poly(4-bromo styrene) (PBrS) and supported on a Si substrate. The top vacuum interface shows two relaxation modes: one fast and one slow, while the buried polymer-polymer interface shows a single slow mode. The slow mode of the top interface is similar in magnitude and wave vector dependence to the single mode of the buried interface. The dynamics are consistent with a low-viscosity mixed layer between the PS and PBrS and coupling of the capillary wave fluctuations between this layer and the PS.
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Affiliation(s)
- Xuesong Hu
- Intense Pulsed Neutron Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
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Jiang Z, Kim H, Mochrie SGJ, Lurio LB, Sinha SK. Surface and interfacial dynamics of polymeric bilayer films. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:011603. [PMID: 16907103 DOI: 10.1103/physreve.74.011603] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Indexed: 05/11/2023]
Abstract
The theory for surface dynamics of the thermally excited fluctuations on a homogenous single-layer film of arbitrary depth is generalized to describe surface and interfacial dynamics of polymeric liquid bilayer films in terms of susceptibilities, power spectra, and characteristic relaxation time constants. The effects on surface dynamics originating from viscosity inhomogeneities close to the surface and interfacial regions are investigated by the bilayer theory and compared with the surface dynamics of homogeneous single-layer films under nonslip and slip boundary conditions. Our bilayer theory can also be extended to study interfacial dynamics of more generalized multilayer systems. The effects of viscoelasticity and van der Waals interactions on surface and interfacial dynamics are also briefly discussed.
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Affiliation(s)
- Zhang Jiang
- Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
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