101
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Wingert MC, Kwon S, Cai S, Chen R. Fluid-like Surface Layer and Its Flow Characteristics in Glassy Nanotubes. NANO LETTERS 2016; 16:7545-7550. [PMID: 27798834 DOI: 10.1021/acs.nanolett.6b03377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We show that amorphous silica and Si nanotubes can flow at room temperature under Giga-Pascal order stress when going to the nanometer scale. This creep behavior is unique for the amorphous nanotubes and is absent in crystalline Si nanotubes of similar dimensions. A core-shell model shows that there exists an approximately 1 nm thick viscoelastic "fluid-like" surface layer, which exhibits a room temperature viscosity equivalent to that of bulk glass above 1000 °C.
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Affiliation(s)
- Matthew C Wingert
- Department of Mechanical and Aerospace Engineering, University of California, San Diego , La Jolla, California 92093, United States
| | - Soonshin Kwon
- Department of Mechanical and Aerospace Engineering, University of California, San Diego , La Jolla, California 92093, United States
| | - Shengqiang Cai
- Department of Mechanical and Aerospace Engineering, University of California, San Diego , La Jolla, California 92093, United States
| | - Renkun Chen
- Department of Mechanical and Aerospace Engineering, University of California, San Diego , La Jolla, California 92093, United States
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102
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Zhang Y, Potter R, Zhang W, Fakhraai Z. Using tobacco mosaic virus to probe enhanced surface diffusion of molecular glasses. SOFT MATTER 2016; 12:9115-9120. [PMID: 27759140 DOI: 10.1039/c6sm01566b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Recent studies have shown that diffusion on the surface of organic glasses can be many orders of magnitude faster than bulk diffusion. Developing new probes that can readily measure surface diffusion can help study the effect of parameters such as chemical structure, intermolecular interaction, molecules' shape and size on the enhanced surface diffusion. In this study, we develop a novel probe that significantly simplifies these types of studies. Tobacco mosaic virus (TMV) is used as probe particle to measure surface diffusion coefficient of molecular glass N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD). The evolution of the meniscus formed around TMV is probed as a function of time at various temperatures. TMV has a well-defined, mono-dispersed, cylindrical shape, with a large aspect-ratio (average diameter of 16.6 nm, length of 300 nm). As such, the shape of the meniscus around the center of TMV is semi-two dimensional, which compared to using a nanosphere as probe, increases the driving force for meniscus formation and simplifies the analysis of surface diffusion. We show that under these conditions, after a short transient time the shape of the meniscus is self-similar, allowing accurate determination of the surface diffusion coefficient. Measurements at various temperatures are then performed to investigate the temperature dependence of the surface diffusion coefficient. It is found that surface diffusion is greatly enhanced in TPD and has a lower activation barrier compared to the bulk counterpart. These observations are consistent with previous studies of surface diffusion on molecular glasses, demonstrating the accuracy of this method.
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Affiliation(s)
- Yue Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
| | - Richard Potter
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
| | - William Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
| | - Zahra Fakhraai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
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103
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Ilton M, Couchman MMP, Gerbelot C, Benzaquen M, Fowler PD, Stone HA, Raphaël E, Dalnoki-Veress K, Salez T. Capillary Leveling of Freestanding Liquid Nanofilms. PHYSICAL REVIEW LETTERS 2016; 117:167801. [PMID: 27792365 DOI: 10.1103/physrevlett.117.167801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Indexed: 06/06/2023]
Abstract
We report on the capillary-driven leveling of a topographical perturbation at the surface of a freestanding liquid nanofilm. The width of a stepped surface profile is found to evolve as the square root of time. The hydrodynamic model is in excellent agreement with the experimental data. In addition to exhibiting an analogy with diffusive processes, this novel system serves as a precise nanoprobe for the rheology of liquids at interfaces in a configuration that avoids substrate effects.
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Affiliation(s)
- Mark Ilton
- Department of Physics & Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Miles M P Couchman
- Department of Physics & Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Cedric Gerbelot
- Laboratoire de Physico-Chimie Théorique, UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 75005 Paris, France
| | - Michael Benzaquen
- Laboratoire de Physico-Chimie Théorique, UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 75005 Paris, France
| | - Paul D Fowler
- Department of Physics & Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Elie Raphaël
- Laboratoire de Physico-Chimie Théorique, UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 75005 Paris, France
| | - Kari Dalnoki-Veress
- Department of Physics & Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
- Laboratoire de Physico-Chimie Théorique, UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 75005 Paris, France
| | - Thomas Salez
- Laboratoire de Physico-Chimie Théorique, UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 75005 Paris, France
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA
- Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, Hokkaido 060-0808, Japan
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104
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Tarnacka M, Kaminski K, Mapesa EU, Kaminska E, Paluch M. Studies on the Temperature and Time Induced Variation in the Segmental and Chain Dynamics in Poly(propylene glycol) Confined at the Nanoscale. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01237] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Magdalena Tarnacka
- Institute
of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
- Silesian
Center for Education and Interdisciplinary Research, University of Silesia, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
| | - Kamil Kaminski
- Institute
of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
| | - Emmanuel U. Mapesa
- Institute
of Experimental Physics I, University of Leipzig, Linnéstraße
5, 04103 Leipzig, Germany
| | - Ewa Kaminska
- Department
of Pharmacognosy and Phytochemistry, Medical University of Silesia in Katowice, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Jagiellonska 4, 41-200 Sosnowiec, Poland
| | - Marian Paluch
- Institute
of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
- Silesian
Center for Education and Interdisciplinary Research, University of Silesia, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
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105
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Zuo B, Tian H, Liang Y, Xu H, Zhang W, Zhang L, Wang X. Probing the rheological properties of supported thin polystyrene films by investigating the growth dynamics of wetting ridges. SOFT MATTER 2016; 12:6120-6131. [PMID: 27355155 DOI: 10.1039/c6sm00881j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Despite its importance in the processing of nanomaterials, the rheological behavior of thin polymer films is poorly understood, partly due to the inherent measurement challenges. Herein, we have developed a facile method for investigating the rheological behavior of supported thin polymeric films by monitoring the growth of the "wetting ridge"-a microscopic protrusion on the film surface due to the capillary forces exerted by a drop of ionic liquid placed on the film surface. It was found that the growth dynamics of the wetting ridge and the behavior of polystyrene rheology are directly linked. Important rheological properties, such as the flow temperature (Tf), viscosity (η), and terminal relaxation time (τ0) of thin polystyrene films, can be derived by studying the development of the height of the wetting ridge with time and the sample temperature. Rheological studies using the proposed approach for supported thin polystyrene (PS) films with thickness down to 20 nm demonstrate that the PS thin film exhibits facilitated flow, with reduced viscosity and lowered viscous temperature and a shortened rubbery plateau, when SiOx-Si was used as the substrate. However, sluggish flow was observed for the PS film supported by hydrogen-passivated silicon substrates (H-Si). The differences in enthalpic interactions between PS and the substrates are the reason for this divergence in the whole-chain mobility and flow ability of thin PS films deposited on SiOx-Si and H-Si surfaces. These results indicate that this approach could be a reliable rheological probe for supported thin polymeric films with different thicknesses and various substrates.
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Affiliation(s)
- Biao Zuo
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Houkuan Tian
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Yongfeng Liang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Hao Xu
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Wei Zhang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Li Zhang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Xinping Wang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
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106
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Zhang W, Teerakapibal R, Yu L. Surface Mobility of Amorphous o-Terphenyl: A Strong Inhibitory Effect of Low-Concentration Polystyrene. J Phys Chem B 2016; 120:6842-7. [DOI: 10.1021/acs.jpcb.6b04606] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wei Zhang
- School of Pharmacy and ‡Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Rattavut Teerakapibal
- School of Pharmacy and ‡Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Lian Yu
- School of Pharmacy and ‡Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
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107
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Nguyen D, Zhu ZG, Pringle B, Lyding J, Wang WH, Gruebele M. Composition-dependent metallic glass alloys correlate atomic mobility with collective glass surface dynamics. Phys Chem Chem Phys 2016; 18:16856-61. [PMID: 27283239 DOI: 10.1039/c6cp02654k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Glassy metallic alloys are richly tunable model systems for surface glassy dynamics. Here we study the correlation between atomic mobility, and the hopping rate of surface regions (clusters) that rearrange collectively on a minute to hour time scale. Increasing the proportion of low-mobility copper atoms in La-Ni-Al-Cu alloys reduces the cluster hopping rate, thus establishing a microscopic connection between atomic mobility and dynamics of collective rearrangements at a glass surface made from freshly exposed bulk glass. One composition, La60Ni15Al15Cu10, has a surface resistant to re-crystallization after three heating cycles. When thermally cycled, surface clusters grow in size from about 5 glass-forming units to about 8 glass-forming units, evidence of surface aging without crystal formation, although its bulk clearly forms larger crystalline domains. Such kinetically stable glass surfaces may be of use in applications where glassy coatings stable against heating are needed.
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Affiliation(s)
- Duc Nguyen
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA. and Beckman Institute, University of Illinois, Urbana, Illinois 61801, USA
| | - Zhi-Guang Zhu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Brian Pringle
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA.
| | - Joseph Lyding
- Beckman Institute, University of Illinois, Urbana, Illinois 61801, USA and Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801, USA
| | - Wei-Hua Wang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Martin Gruebele
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA. and Beckman Institute, University of Illinois, Urbana, Illinois 61801, USA and Department of Physics, University of Illinois, Urbana, Illinois 61801, USA
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108
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Zuo B, Xu J, Sun S, Liu Y, Yang J, Zhang L, Wang X. Stepwise crystallization and the layered distribution in crystallization kinetics of ultra-thin poly(ethylene terephthalate) film. J Chem Phys 2016; 144:234902. [DOI: 10.1063/1.4953852] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Biao Zuo
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Jianquan Xu
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Shuzheng Sun
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Yue Liu
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Juping Yang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Li Zhang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Xinping Wang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China
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109
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Christie D, Zhang C, Fu J, Koel B, Priestley RD. Glass transition temperature of colloidal polystyrene dispersed in various liquids. ACTA ACUST UNITED AC 2016. [DOI: 10.1002/polb.24082] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Dane Christie
- Department of Chemical and Biological Engineering; Princeton University; Princeton New Jersey 08544
| | - Chuan Zhang
- Department of Chemical and Biological Engineering; Princeton University; Princeton New Jersey 08544
| | - Jie Fu
- Department of Chemistry; Princeton University; Princeton New Jersey 08544
| | - Bruce Koel
- Department of Chemical and Biological Engineering; Princeton University; Princeton New Jersey 08544
- Department of Chemistry; Princeton University; Princeton New Jersey 08544
| | - Rodney D. Priestley
- Department of Chemical and Biological Engineering; Princeton University; Princeton New Jersey 08544
- Princeton Institute for the Science and Technology of Materials; Princeton University; Princeton New Jersey 08544
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110
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Yoon H, McKenna GB. Dynamic and temperature dependent response of physical vapor deposited Se in freely standing nanometric thin films. J Chem Phys 2016; 144:184501. [DOI: 10.1063/1.4948322] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Heedong Yoon
- Department of Chemical Engineering, Whitacre College of Engineering, Texas Tech University, Lubbock, Texas 79409-4121, USA
| | - Gregory B. McKenna
- Department of Chemical Engineering, Whitacre College of Engineering, Texas Tech University, Lubbock, Texas 79409-4121, USA
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111
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Yu L. Surface mobility of molecular glasses and its importance in physical stability. Adv Drug Deliv Rev 2016; 100:3-9. [PMID: 26774328 DOI: 10.1016/j.addr.2016.01.005] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 01/04/2016] [Accepted: 01/05/2016] [Indexed: 11/26/2022]
Abstract
Amorphous molecular materials (molecular glasses) are useful for drug delivery, bio-preservation and organic electronics. A central issue in developing amorphous materials is the stability against crystallization and other transformations that can compromise material performance. We review recent progress in understanding the stability of molecular glasses, particularly the role for surface mobility. Surface diffusion in molecular glasses can be vastly faster than bulk diffusion. This high surface mobility enables fast crystal growth on the free surface. In this process, surface crystals grow upward and laterally, with the lateral growth rate being roughly proportional to surface diffusivity. Surface mobility also influences bulk crystal growth as the process can create fracture and free surfaces. During vapor deposition, surface mobility allows efficient equilibration of newly deposited molecules, producing low-energy, high-density glasses that are equivalent to liquid-cooled glasses aged for thousands of years. Free surfaces can accelerate chemical degradation of proteins. Measures for inhibiting surface-facilitated transformations include minimizing free surfaces, applying surface coatings, and preventing fracture.
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112
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Andreotti B, Bäumchen O, Boulogne F, Daniels KE, Dufresne ER, Perrin H, Salez T, Snoeijer JH, Style RW. Solid capillarity: when and how does surface tension deform soft solids? SOFT MATTER 2016; 12:2993-2996. [PMID: 26936296 DOI: 10.1039/c5sm03140k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Soft solids differ from stiff solids in an important way: their surface stresses can drive large deformations. Based on a topical workshop held in the Lorentz Center in Leiden, this Opinion highlights some recent advances in the growing field of solid capillarity and poses key questions for its advancement.
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Affiliation(s)
- Bruno Andreotti
- Physique et Mécanique des Milieux Hétérogènes, UMR 7636 ESPCI-CNRS, Université Paris-Diderot, 10 rue Vauquelin, 75005, Paris, France
| | - Oliver Bäumchen
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), D-37077 Göttingen, Germany
| | - François Boulogne
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Karen E Daniels
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Eric R Dufresne
- School of Engineering and Applied Sciences, Yale University, New Haven, CT 06520, USA and Department of Materials, ETH Zürich, CH-8093 Zurich, Switzerland.
| | - Hugo Perrin
- Physique et Mécanique des Milieux Hétérogènes, UMR 7636 ESPCI-CNRS, Université Paris-Diderot, 10 rue Vauquelin, 75005, Paris, France
| | - Thomas Salez
- PCT Lab, UMR CNRS 7083 Gulliver, ESPCI ParisTech, PSL Research University, 75005 Paris, France
| | - Jacco H Snoeijer
- Physics of Fluids Group, Faculty of Science and Technology, and Burgers Center for Fluid Dynamics, University of Twente, 7500AE Enschede, The Netherlands and Mesoscopic Transport Phenomena, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Robert W Style
- Mathematical Institute, University of Oxford, Oxford, OX1 3LB, UK
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113
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Wang Z, Lv Q, Chen S, Li C, Sun S, Hu S. Effect of Interfacial Bonding on Interphase Properties in SiO2/Epoxy Nanocomposite: A Molecular Dynamics Simulation Study. ACS APPLIED MATERIALS & INTERFACES 2016; 8:7499-508. [PMID: 26927032 DOI: 10.1021/acsami.5b11810] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Atomistic molecular dynamics simulations have been performed to explore the effect of interfacial bonding on the interphase properties of a nanocomposite system that consists of a silica nanoparticle and the highly cross-linked epoxy matrix. For the structural properties, results show that interfacial covalent bonding can broaden the interphase region by increasing the radial effect range of fluctuated mass density and oriented chains, as well as strengthen the interphase region by improving the thermal stability of interfacial van der Waals excluded volume and reducing the proportion of cis conformers of epoxy segments. The improved thermal stability of the interphase region in the covalently bonded model results in an increase of ∼21 K in the glass transition temperature (Tg) compared to that of the pure epoxy. It is also found that interfacial covalent bonding mainly restricts the volume thermal expansion of the model at temperatures near or larger than Tg. Furthermore, investigations from mean-square displacement and fraction of immobile atoms point out that interfacial covalent and noncovalent bonding induces lower and higher mobility of interphase atoms than that of the pure epoxy, respectively. The obtained critical interfacial bonding ratio when the interphase and matrix atoms have the same mobility is 5.8%. These results demonstrate that the glass transitions of the interphase and matrix will be asynchronous when the interfacial bonding ratio is not 5.8%. Specifically, the interphase region will trigger the glass transition of the matrix when the ratio is larger than 5.8%, whereas it restrains the glass transition of the matrix when the ratio is smaller than 5.8%.
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Affiliation(s)
- Zhikun Wang
- College of Science, China University of Petroleum , Qingdao 266580 Shandong Province, P. R. China
| | - Qiang Lv
- College of Science, China University of Petroleum , Qingdao 266580 Shandong Province, P. R. China
| | - Shenghui Chen
- College of Science, China University of Petroleum , Qingdao 266580 Shandong Province, P. R. China
| | - Chunling Li
- College of Science, China University of Petroleum , Qingdao 266580 Shandong Province, P. R. China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong (China University of Petroleum) , Qingdao 266580 Shandong Province, P. R. China
| | - Shuangqing Sun
- College of Science, China University of Petroleum , Qingdao 266580 Shandong Province, P. R. China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong (China University of Petroleum) , Qingdao 266580 Shandong Province, P. R. China
| | - Songqing Hu
- College of Science, China University of Petroleum , Qingdao 266580 Shandong Province, P. R. China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong (China University of Petroleum) , Qingdao 266580 Shandong Province, P. R. China
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114
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Lan T, Torkelson JM. Fragility-Confinement Effects: Apparent Universality as a Function of Scaled Thickness in Films of Freely Deposited, Linear Polymer and Its Absence in Densely Grafted Brushes. Macromolecules 2016. [DOI: 10.1021/acs.macromol.5b02489] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tian Lan
- Department of Materials Science
and Engineering and ‡Department of Chemical and Biological
Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - John M. Torkelson
- Department of Materials Science
and Engineering and ‡Department of Chemical and Biological
Engineering, Northwestern University, Evanston, Illinois 60208, United States
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115
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Affiliation(s)
- Wei Zhang
- †School of Pharmacy and ‡Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53705, United States
| | - Lian Yu
- †School of Pharmacy and ‡Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53705, United States
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116
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Rivetti M, Salez T, Benzaquen M, Raphaël E, Bäumchen O. Universal contact-line dynamics at the nanoscale. SOFT MATTER 2015; 11:9247-9253. [PMID: 26481774 DOI: 10.1039/c5sm01907a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The relaxation dynamics of the contact angle between a viscous liquid and a smooth substrate is studied at the nanoscale. Through atomic force microscopy measurements of polystyrene nanostripes we simultaneously monitor both the temporal evolution of the liquid-air interface and the position of the contact line. The initial configuration exhibits high curvature gradients and a non-equilibrium contact angle that drive liquid flow. Both these conditions are relaxed to achieve the final state, leading to three successive regimes in time: (i) stationary contact line levelling; (ii) receding contact line dewetting; (iii) collapse of the two fronts. For the first regime, we reveal the existence of a self-similar evolution of the liquid interface, which is in excellent agreement with numerical calculations from a lubrication model. For different liquid viscosities and film thicknesses we provide evidence for a transition to dewetting featuring a universal critical contact angle and dimensionless time.
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Affiliation(s)
- Marco Rivetti
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), Am Faßberg 17, 37077 Göttingen, Germany.
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117
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Mirigian S, Schweizer KS. Theory of activated glassy relaxation, mobility gradients, surface diffusion, and vitrification in free standing thin films. J Chem Phys 2015; 143:244705. [DOI: 10.1063/1.4937953] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Stephen Mirigian
- Departments of Materials Science and Chemistry, University of Illinois, Urbana, Illinois 61801, USA
| | - Kenneth S. Schweizer
- Departments of Materials Science and Chemistry, University of Illinois, Urbana, Illinois 61801, USA
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118
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Zhang L, Elupula R, Grayson SM, Torkelson JM. Major Impact of Cyclic Chain Topology on the Tg-Confinement Effect of Supported Thin Films of Polystyrene. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b02474] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
| | - Ravinder Elupula
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Scott M. Grayson
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
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119
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Affiliation(s)
- David S. Simmons
- Department of Polymer Engineering; University of Akron; 250 South Forge St Akron OH 44325 USA
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120
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Haji-Akbari A, Debenedetti PG. Thermodynamic and kinetic anisotropies in octane thin films. J Chem Phys 2015; 143:214501. [PMID: 26646882 DOI: 10.1063/1.4935801] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Confinement breaks the translational symmetry of materials, making all thermodynamic and kinetic quantities functions of position. Such symmetry breaking can be used to obtain configurations that are not otherwise accessible in the bulk. Here, we use computer simulations to explore the effect of substrate-liquid interactions on thermodynamic and kinetic anisotropies induced by a solid substrate. We consider n-octane nano-films that are in contact with substrates with varying degrees of attraction, parameterized by an interaction parameter ϵS. Complete freezing of octane nano-films is observed at low temperatures, irrespective of ϵS, while at intermediate temperatures, a frozen monolayer emerges at solid-liquid and vapor-liquid interfaces. By carefully inspecting the profiles of translational and orientational relaxation times, we confirm that the translational and orientational degrees of freedom are decoupled at these frozen monolayers. At sufficiently high temperatures, however, free interfaces and solid-liquid interfaces close to loose (low-ϵS) substrates undergo "pre-freezing," characterized by mild peaks in several thermodynamic quantities. Two distinct dynamic regimes are observed at solid-liquid interfaces. The dynamics is accelerated in the vicinity of loose substrates, while sticky (high-ϵS) substrates decelerate dynamics, sometimes by as much as two orders of magnitude. These two distinct dynamical regimes have been previously reported by Haji-Akbari and Debenedetti [J. Chem. Phys. 141, 024506 (2014)] for a model atomic glass-forming liquid. We also confirm the existence of two correlations-proposed in the above-mentioned work-in solid-liquid subsurface regions of octane thin films, i.e., a correlation between atomic density and normal stress, and between atomic translational relaxation time and lateral stress. Finally, we inspect the ability of different regions of an octane film to explore the potential energy landscape by performing inherent structure calculations, and observe no noticeable difference between the free surface and the bulk in efficiently exploring the potential energy landscape. This is unlike the films of model atomic glass formers that tend to sample their respective landscape more efficiently at free surfaces. We discuss the implications of this finding to the ability of octane-and other n-alkanes-to form ultrastable glasses.
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Affiliation(s)
- Amir Haji-Akbari
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Pablo G Debenedetti
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
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121
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Madkour S, Yin H, Füllbrandt M, Schönhals A. Calorimetric evidence for a mobile surface layer in ultrathin polymeric films: poly(2-vinyl pyridine). SOFT MATTER 2015; 11:7942-7952. [PMID: 26324951 DOI: 10.1039/c5sm01558h] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Specific heat spectroscopy was used to study the dynamic glass transition of ultrathin poly(2-vinyl pyridine) films (thicknesses: 405-10 nm). The amplitude and the phase angle of the differential voltage were obtained as a measure of the complex heat capacity. In a traditional data analysis, the dynamic glass transition temperature Tg is estimated from the phase angle. These data showed no thickness dependency on Tg down to 22 nm (error of the measurement of ±3 K). A derivative-based method was established, evidencing a decrease in Tg with decreasing thickness up to 7 K, which can be explained by a surface layer. For ultrathin films, data showed broadening at the lower temperature side of the spectra, supporting the existence of a surface layer. Finally, temperature dependence of the heat capacity in the glassy and liquid states changes with film thickness, which can be considered as a confinement effect.
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Affiliation(s)
- Sherif Madkour
- BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, D-12200 Berlin, Germany.
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122
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Chen F, Peng D, Ogata Y, Tanaka K, Yang Z, Fujii Y, Yamada NL, Lam CH, Tsui OKC. Confinement Effect on the Effective Viscosity of Plasticized Polymer Films. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b01780] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- F. Chen
- Department
of Physics, Boston University, Boston, Massachusetts 02215, United States
| | - D. Peng
- Department
of Physics, Boston University, Boston, Massachusetts 02215, United States
| | - Y. Ogata
- Department
of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan
| | - K. Tanaka
- Department
of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan
| | - Z. Yang
- Department
of Polymer Science and Engineering, Soochow University, Suzhou, P. R. China
| | - Y. Fujii
- National Institute
for Materials Science, 1-1 Namiki, Tsukuba, Japan
| | - N. L. Yamada
- Neutron
Science Laboratory, High Energy Accelerator Research Organization, Ibaraki 305-0044, Japan
| | - C.-H. Lam
- Department
of Applied Physics, Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - O. K. C. Tsui
- Department
of Physics, Boston University, Boston, Massachusetts 02215, United States
- Division of Materials Science & Engineering, Boston University, Brookline, Massachusetts 02446, United States
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123
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Singer JP, Kooi SE, Thomas EL. Focused laser-induced marangoni dewetting for patterning polymer thin films. ACTA ACUST UNITED AC 2015. [DOI: 10.1002/polb.23906] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jonathan P. Singer
- Department of Mechanical and Aerospace Engineering; Rutgers University; 98 Brett Road, B235 Piscataway New Jersey 08854
| | - Steven E. Kooi
- Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology; 500 Technology Square, NE47-400 Cambridge Massachusetts 02139
| | - Edwin L. Thomas
- George R. Brown School of Engineering; 6100 Main Street, Duncan Hall Room 1016 Houston Texas 77005
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124
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Zuo B, He X, Wang Y, Xu J, Yang J, Wang X. Relationship between Segmental Relaxation of Polystyrene Films and Stick-Slip Behavior during Dynamic Wetting of Liquid Droplets on Their Surfaces. J Phys Chem B 2015; 119:12325-35. [PMID: 26305980 DOI: 10.1021/acs.jpcb.5b06078] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel method was previously reported for detecting the glass transition of thin polystyrene (PS) films by correlating the relationships between the temperature-dependent viscoelasticity of the PS films and stick-slip behavior on their surfaces during dynamic wetting of liquid droplets. In the present study, the frequency dependence of the stick-slip behavior is investigated. The results show that the stick-slip behavior of liquid dynamic wetting on PS films is dependent on the contact line velocity, which is related to the deformation frequency of the PS surface during the moving liquid front. The stick-slip behavior was revealed to be determined by a dimensionless parameter (ξ), which is the ratio of the PS segmental relaxation time (τα) and the characteristic time (τc) for PS surface deformation near the droplet contact line. When ξ is close to 1 (τα ≈ τc), the Δθ (jumping angle), a scale of the stick-slip behavior, reaches a maximum. This correlation between Δθ and ξ demonstrates that the stick-slip behavior is related to the energy dissipation caused by the PS α-relaxation process, and the peak temperature (or frequency) in Δθ corresponds to the α-relaxation temperature (time) of the polymer. These results strongly demonstrate that the utilization of the stick-slip behavior is a creditable method, similar to dynamic viscoelastic measurement, for probing the glass transition and segmental relaxation of thin polymer films.
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Affiliation(s)
- Biao Zuo
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University , Hangzhou 310018, P. R. China
| | - Xumiao He
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University , Hangzhou 310018, P. R. China
| | - Yuping Wang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University , Hangzhou 310018, P. R. China
| | - Jianquan Xu
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University , Hangzhou 310018, P. R. China
| | - Juping Yang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University , Hangzhou 310018, P. R. China
| | - Xinping Wang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University , Hangzhou 310018, P. R. China
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125
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126
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Jiang N, Endoh MK, Koga T. Structures and Dynamics of Adsorbed Polymer Nanolayers on Planar Solids. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/978-3-319-21948-6_6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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127
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Affiliation(s)
- Xiguang Li
- Whitacre College of Engineering,
Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409-4121, United States
| | - Gregory B. McKenna
- Whitacre College of Engineering,
Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409-4121, United States
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128
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Yin H, Madkour S, Schönhals A. Unambiguous Evidence for a Highly Mobile Surface Layer in Ultrathin Polymer Films by Specific Heat Spectroscopy on Blends. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b01259] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Huajie Yin
- BAM Bundesanstalt
für Materialforschung
und -prüfung, Unter den Eichen
87, 12205 Berlin, Germany
| | - Sherif Madkour
- BAM Bundesanstalt
für Materialforschung
und -prüfung, Unter den Eichen
87, 12205 Berlin, Germany
| | - Andreas Schönhals
- BAM Bundesanstalt
für Materialforschung
und -prüfung, Unter den Eichen
87, 12205 Berlin, Germany
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129
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Chen F, Peng D, Lam CH, Tsui OKC. Viscosity and Surface-Promoted Slippage of Thin Polymer Films Supported by a Solid Substrate. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b01002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Chi-Hang Lam
- Department
of Applied Physics, Hong Kong Polytechnic University, Hung Hom, Hong Kong
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130
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Salez T, Salez J, Dalnoki-Veress K, Raphaël E, Forrest JA. Cooperative strings and glassy interfaces. Proc Natl Acad Sci U S A 2015; 112:8227-31. [PMID: 26100908 PMCID: PMC4500214 DOI: 10.1073/pnas.1503133112] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We introduce a minimal theory of glass formation based on the ideas of molecular crowding and resultant string-like cooperative rearrangement, and address the effects of free interfaces. In the bulk case, we obtain a scaling expression for the number of particles taking part in cooperative strings, and we recover the Adam-Gibbs description of glassy dynamics. Then, by including thermal dilatation, the Vogel-Fulcher-Tammann relation is derived. Moreover, the random and string-like characters of the cooperative rearrangement allow us to predict a temperature-dependent expression for the cooperative length ξ of bulk relaxation. Finally, we explore the influence of sample boundaries when the system size becomes comparable to ξ. The theory is in agreement with measurements of the glass-transition temperature of thin polymer films, and allows quantification of the temperature-dependent thickness hm of the interfacial mobile layer.
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Affiliation(s)
- Thomas Salez
- Perimeter Institute for Theoretical Physics, Waterloo, ON, Canada N2L 2Y5; Laboratoire de Physico-Chimie Théorique, UMR CNRS Gulliver 7083, ESPCI ParisTech, PSL Research University, 75005 Paris, France;
| | - Justin Salez
- Laboratoire de Probabilités et Modèles Aléatoires, Université Paris Diderot, 75013 Paris, France
| | - Kari Dalnoki-Veress
- Laboratoire de Physico-Chimie Théorique, UMR CNRS Gulliver 7083, ESPCI ParisTech, PSL Research University, 75005 Paris, France; Department of Physics and Astronomy, McMaster University, Hamilton, ON, Canada L8S 4M1
| | - Elie Raphaël
- Laboratoire de Physico-Chimie Théorique, UMR CNRS Gulliver 7083, ESPCI ParisTech, PSL Research University, 75005 Paris, France
| | - James A Forrest
- Perimeter Institute for Theoretical Physics, Waterloo, ON, Canada N2L 2Y5; Department of Physics & Astronomy, University of Waterloo, Waterloo, ON, Canada N2L 3G1
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131
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Glor EC, Fakhraai Z. Facilitation of interfacial dynamics in entangled polymer films. J Chem Phys 2015; 141:194505. [PMID: 25416896 DOI: 10.1063/1.4901512] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this article, we use cooling-rate dependent Tg measurements (CR-Tg) to indirectly probe the relaxation dynamics of supported polystyrene thin films of various molecular weights, all chosen to be above the entanglement molecular weight. We show that the dynamics in these films deviate from bulk dynamics below a temperature T(*) = Tg + 6 K = 380 K ± 1 K. We show that T(*) for films of all thicknesses and molecular weights is the same as the temperature at which the free surface dynamics deviate from the bulk dynamics. The apparent activation barrier of the glass transition in thin films decreases towards that of the free surface as the film thickness decreases. This provides strong evidence that thin film dynamics are facilitated by the enhanced mobility at the free surface. The observation of T(*) can help resolve some seemingly contradictory data by suggesting that studies performed at higher temperatures (T > T(*)), or which probe shorter relaxation times (τ < τ(*) ∼ 1 s) would not observe properties that deviate from bulk values. We also demonstrate that the relaxation dynamics of supported entangled polystyrene films slow down slightly as the molecular weight of polystyrene increases. An eight nanometer film of Mw =2240 kg/mol polystyrene shows a Tg reduction of 27 K at a cooling rate of 1 K/min, while a film of the same thickness made of Mw =45.8 kg/mol polystyrene has a 36 K reduction of Tg compared to the bulk film at the same cooling rate. We hypothesize this is either due to the density of a dynamically "dead" layer near the substrate increasing with molecular weight, or partial anchoring of long chains, which could hinder segmental diffusion near the free surface.
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Affiliation(s)
- Ethan C Glor
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Zahra Fakhraai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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132
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Lan T, Torkelson JM. Substantial spatial heterogeneity and tunability of glass transition temperature observed with dense polymer brushes prepared by ARGET ATRP. POLYMER 2015. [DOI: 10.1016/j.polymer.2015.03.047] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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133
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Rissanou AN, Harmandaris V. Structural and Dynamical Properties of Polystyrene Thin Films Supported by Multiple Graphene Layers. Macromolecules 2015. [DOI: 10.1021/ma502524e] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Anastassia N. Rissanou
- Institute of Applied and Computational
Mathematics (IACM), Foundation for Research and Technology Hellas (FORTH), GR-71110 Heraklion, Crete Greece
- Department of Mathematics and Applied Mathematics, University of Crete, GR-71409, Heraklion, Crete Greece
| | - Vagelis Harmandaris
- Institute of Applied and Computational
Mathematics (IACM), Foundation for Research and Technology Hellas (FORTH), GR-71110 Heraklion, Crete Greece
- Department of Mathematics and Applied Mathematics, University of Crete, GR-71409, Heraklion, Crete Greece
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134
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Zhang W, Brian CW, Yu L. Fast surface diffusion of amorphous o-terphenyl and its competition with viscous flow in surface evolution. J Phys Chem B 2015; 119:5071-8. [PMID: 25803422 DOI: 10.1021/jp5127464] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Surface self-diffusion coefficients have been measured for the model molecular glass o-terphenyl (OTP) through surface-grating decay driven by capillarity. The decay mechanism transitions from viscous flow at high temperatures to surface diffusion at low temperatures; for 1000 nm wavelength gratings, the transition occurs at Tg + 11 K. The surface diffusion of OTP is 10(8) times faster than bulk diffusion at Tg and even faster at lower temperatures because of its weaker temperature dependence. At Tg, OTP has approximately the same bulk diffusivity as the previously studied molecular liquid indomethacin, but its surface diffusion is 100 times faster. While the molecular glass-formers exhibit transitions from viscous flow to surface diffusion as the mechanism of capillarity-driven surface flattening, polystyrenes and silicates show no such transition under comparable conditions, suggesting slower surface diffusion on these materials and a general dependence of surface diffusion on intermolecular forces. The velocity of surface crystal growth on molecular glasses is proportional to surface diffusivity, indicating a common kinetic barrier for both processes for temperatures below Tg.
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Affiliation(s)
- Wei Zhang
- †School of Pharmacy and ‡Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Caleb W Brian
- †School of Pharmacy and ‡Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Lian Yu
- †School of Pharmacy and ‡Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
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135
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Tunable molecular orientation and elevated thermal stability of vapor-deposited organic semiconductors. Proc Natl Acad Sci U S A 2015; 112:4227-32. [PMID: 25831545 DOI: 10.1073/pnas.1421042112] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Physical vapor deposition is commonly used to prepare organic glasses that serve as the active layers in light-emitting diodes, photovoltaics, and other devices. Recent work has shown that orienting the molecules in such organic semiconductors can significantly enhance device performance. We apply a high-throughput characterization scheme to investigate the effect of the substrate temperature (Tsubstrate) on glasses of three organic molecules used as semiconductors. The optical and material properties are evaluated with spectroscopic ellipsometry. We find that molecular orientation in these glasses is continuously tunable and controlled by Tsubstrate/Tg, where Tg is the glass transition temperature. All three molecules can produce highly anisotropic glasses; the dependence of molecular orientation upon substrate temperature is remarkably similar and nearly independent of molecular length. All three compounds form "stable glasses" with high density and thermal stability, and have properties similar to stable glasses prepared from model glass formers. Simulations reproduce the experimental trends and explain molecular orientation in the deposited glasses in terms of the surface properties of the equilibrium liquid. By showing that organic semiconductors form stable glasses, these results provide an avenue for systematic performance optimization of active layers in organic electronics.
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136
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Yang Q, Xu Q, Loos K. Enhanced Polystyrene Surface Mobility under Carbon Dioxide at Low Temperature for Nanoparticle Embedding Control. Macromolecules 2015. [DOI: 10.1021/ma5025686] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Qiuyan Yang
- Department of Polymer
Chemistry, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Qun Xu
- College
of Material Science and Engineering, Zhengzhou University, Zhengzhou 450001, P. R. China
| | - Katja Loos
- Department of Polymer
Chemistry, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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137
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Hasebe M, Musumeci D, Yu L. Fast Surface Crystallization of Molecular Glasses: Creation of Depletion Zones by Surface Diffusion and Crystallization Flux. J Phys Chem B 2015; 119:3304-11. [DOI: 10.1021/jp512400c] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mariko Hasebe
- School of Pharmacy and Department
of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53705, United States
| | - Daniele Musumeci
- School of Pharmacy and Department
of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53705, United States
| | - Lian Yu
- School of Pharmacy and Department
of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53705, United States
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138
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Bao S, Wu Q, Qin W, Yu Q, Wang J, Liang G, Tang BZ. Sensitive and reliable detection of glass transition of polymers by fluorescent probes based on AIE luminogens. Polym Chem 2015. [DOI: 10.1039/c5py00308c] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A sensitive and reliable approach for the detection of the glass transition of polymers using AIE luminogens as fluorescent probes was reported.
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Affiliation(s)
- Suping Bao
- DSAP lab
- PCFM lab
- GDHPPC lab
- School of Chemistry and Chemical Engineering
- Sun Yat-Sen University
| | - Qihua Wu
- DSAP lab
- PCFM lab
- GDHPPC lab
- School of Chemistry and Chemical Engineering
- Sun Yat-Sen University
| | - Wei Qin
- HKUST-Shenzhen Research Institute
- Nanshan, Shenzhen
- China 518057
- Department of Chemistry
- Institute for Advanced Study
| | - Qiuling Yu
- DSAP lab
- PCFM lab
- GDHPPC lab
- School of Chemistry and Chemical Engineering
- Sun Yat-Sen University
| | - Jing Wang
- DSAP lab
- PCFM lab
- GDHPPC lab
- School of Chemistry and Chemical Engineering
- Sun Yat-Sen University
| | - Guodong Liang
- DSAP lab
- PCFM lab
- GDHPPC lab
- School of Chemistry and Chemical Engineering
- Sun Yat-Sen University
| | - Ben Zhong Tang
- HKUST-Shenzhen Research Institute
- Nanshan, Shenzhen
- China 518057
- Department of Chemistry
- Institute for Advanced Study
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139
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Marcon V, van der Vegt NFA. How does low-molecular-weight polystyrene dissolve: osmotic swelling vs. surface dissolution. SOFT MATTER 2014; 10:9059-9064. [PMID: 25300931 DOI: 10.1039/c4sm01636j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
By means of multiscale hierarchical modeling we study the real time evolution of low-molecular-weight polystyrene, below the glass transition temperature, in contact with its solvent, toluene. We observe two concurrent phenomena taking place: (1) the solvent diffuses into the polymer by a Case II mechanism, leading to osmotic driven swelling and progressive chain dilution (inside-out mechanism); (2) polymer chains are solvated, detach from the interface and move into the solvent before the film is completely swollen (outside-in mechanism). From our simulations we conclude that, below the entanglement length, a thin swollen layer, also observed in previous experiments, forms almost instantaneously, which allows for the outside-in mechanism to start a few tens of nanoseconds after the polymer-solvent initial contact. After this initial transient time the two mechanisms are concurrent. We furthermore observe that the presence of the solvent significantly enhances the mobility of the polymer chains of the surface layer, but only in the direction parallel to the interface.
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Affiliation(s)
- Valentina Marcon
- Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Strasse 10, 64287 Darmstadt, Germany.
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140
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Benzaquen M, Fowler P, Jubin L, Salez T, Dalnoki-Veress K, Raphaël E. Approach to universal self-similar attractor for the levelling of thin liquid films. SOFT MATTER 2014; 10:8608-8614. [PMID: 25180467 DOI: 10.1039/c4sm01483a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We compare the capillary levelling of a random surface perturbation on a thin polystyrene film with a theoretical study on the two-dimensional capillary-driven thin film equation. Using atomic force microscopy, we follow the time evolution of samples prepared with different initial perturbations of the free surface. In particular, we show that the surface profiles present long term self-similarity, and furthermore, that they converge to a universal self-similar attractor that only depends on the volume of the perturbation, consistent with the theory. Finally, we look at the convergence time for the different samples and find very good agreement with the analytical predictions.
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Affiliation(s)
- Michael Benzaquen
- Laboratoire de Physico-Chimie Théorique, UMR CNRS 7083 Gulliver, ESPCI ParisTech, PSL Research University, France.
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141
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Mirigian S, Schweizer KS. Communication: Slow relaxation, spatial mobility gradients, and vitrification in confined films. J Chem Phys 2014; 141:161103. [DOI: 10.1063/1.4900507] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Stephen Mirigian
- Department of Materials Science, University of Illinois, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
| | - Kenneth S. Schweizer
- Department of Materials Science, University of Illinois, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illinois 61801, USA
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142
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Lin FY, Steffen W. Capillary wave dynamics of thin liquid polymer films. J Chem Phys 2014; 141:104903. [DOI: 10.1063/1.4894770] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Fan-Yen Lin
- Max Planck Institute for Polymer Research, P.O. Box 3148, 55128 Mainz, Germany
| | - Werner Steffen
- Max Planck Institute for Polymer Research, P.O. Box 3148, 55128 Mainz, Germany
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143
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Haji-Akbari A, Debenedetti PG. The effect of substrate on thermodynamic and kinetic anisotropies in atomic thin films. J Chem Phys 2014; 141:024506. [DOI: 10.1063/1.4885365] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Amir Haji-Akbari
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Pablo G. Debenedetti
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
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Ngai KL, Capaccioli S, Paluch M, Prevosto D. Temperature Dependence of the Structural Relaxation Time in Equilibrium below the Nominal Tg: Results from Freestanding Polymer Films. J Phys Chem B 2014; 118:5608-14. [DOI: 10.1021/jp502846t] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- K. L. Ngai
- Dipartimento
di Fisica, Università di Pisa, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
- CNR-IPCF, Institute for Chemical and Physical Processes, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
| | - Simone Capaccioli
- Dipartimento
di Fisica, Università di Pisa, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
- CNR-IPCF, Institute for Chemical and Physical Processes, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
| | - Marian Paluch
- Institute
of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
| | - Daniele Prevosto
- CNR-IPCF, Institute for Chemical and Physical Processes, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
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145
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Affiliation(s)
- Fei Chen
- Department of Physics, Boston University, Boston, MA 02215, USA
| | - Chi-Hang Lam
- Department of Applied Physics, Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Ophelia K. C. Tsui
- Department of Physics, Boston University, Boston, MA 02215, USA
- Division of Materials Science and Engineering, Boston University, Boston, MA 02215, USA
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