1
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Zhai Q, Gao XY, Lee CS, Ong CY, Yan K, Deng HY, Yang S, Lam CH. Surface mobility gradient and emergent facilitation in glassy films. SOFT MATTER 2024. [PMID: 38757511 DOI: 10.1039/d4sm00221k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Confining glassy polymers into films can substantially modify their local and film-averaged properties. We present a lattice model of film geometry with void-mediated facilitation behaviors but free from any elasticity effect. We analyze the spatially varying viscosity to delineate the transport properties of glassy films. The film mobility measurements reported by Yang et al., Science, 2010, 328, 1676 are successfully reproduced. The flow exhibits a crossover from a simple viscous flow to a surface-dominated regime as the temperature decreases. The propagation of a highly mobile front induced by the free surface is visualized in real space. Our approach provides a microscopic treatment of the observed glassy phenomena.
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Affiliation(s)
- Qiang Zhai
- School of Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an, Shaanxi, 710049, China.
| | - Xin-Yuan Gao
- Department of Physics, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Chun-Shing Lee
- School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China
| | - Chin-Yuan Ong
- School of Physics, Yale University, New Haven, Connecticut, 06520, USA
| | - Ke Yan
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China.
| | - Hai-Yao Deng
- School of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff, CF24 3AA, Wales, UK.
| | - Sen Yang
- School of Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an, Shaanxi, 710049, China.
| | - Chi-Hang Lam
- Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong, China.
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2
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Serna S, Wang T, Torkelson JM. Eliminating the Tg-confinement and fragility-confinement effects in poly(4-methylstyrene) films by incorporation of 3 mol % 2-ethylheyxl acrylate comonomer. J Chem Phys 2024; 160:034903. [PMID: 38235797 DOI: 10.1063/5.0189409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 12/22/2023] [Indexed: 01/19/2024] Open
Abstract
Nanoconfined poly(4-methylstyrene) [P(4-MS)] films exhibit reductions in glass transition temperature (Tg) relative to bulk Tg (Tg,bulk). Ellipsometry reveals that 15-nm-thick P(4-MS) films supported on silicon exhibit Tg - Tg,bulk = - 15 °C. P(4-MS) films also exhibit fragility-confinement effects; fragility decreases ∼60% in going from bulk to a 20-nm-thick film. Previous research found that incorporating 2-6 mol % 2-ethylhexyl acrylate (EHA) comonomer in styrene-based random copolymers eliminates Tg- and fragility-confinement effects in polystyrene. Here, we demonstrate that incorporating 3 mol % EHA in a 4-MS-based random copolymer, 97/3 P(4-MS/EHA), eliminates the Tg- and fragility-confinement effects. The invariance of fragility with nanoconfinement of 97/3 P(4-MS/EHA) films, hypothesized to originate from the interdigitation of ethylhexyl groups, indicates that the presence of EHA prevents the free surface from perturbing chain packing and the cooperative mobility associated with Tg. This method of eliminating confinement effects is advantageous as it relies on the simplest of polymerization methods and neat copolymer only slightly altered in composition from homopolymer. We also investigated whether we could eliminate the Tg-confinement effect with low levels of 2-ethylhexyl methacrylate (EHMA) in 4-MS-based or styrene-based copolymers. Although EHMA is structurally nearly identical to EHA, 4-MS-based and styrene-based copolymers incorporating 4 mol % EHMA exhibit Tg-confinement effects similar to P(4-MS) and polystyrene. These results support the special character of EHA in eliminating confinement effects originating at free surfaces.
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Affiliation(s)
- Sergio Serna
- Department of Chemical and Biological Engineering, Evanston, Illinois 60208, USA
| | - Tong Wang
- Department of Chemical and Biological Engineering, Evanston, Illinois 60208, USA
| | - John M Torkelson
- Department of Chemical and Biological Engineering, Evanston, Illinois 60208, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
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3
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Shimokita K, Yamamoto K, Miyata N, Nakanishi Y, Shibata M, Takenaka M, Yamada NL, Seto H, Aoki H, Miyazaki T. Neutron reflectivity study on the nanostructure of PMMA chains near substrate interfaces based on contrast variation accompanied with small molecule sorption. SOFT MATTER 2023; 19:2082-2089. [PMID: 36808205 DOI: 10.1039/d2sm01482c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
In the case of poly(methyl methacrylate) (PMMA) thin films on a Si substrate, thermal annealing induces the formation of a layer of PMMA chains tightly adsorbed near the substrate interface, and the strongly adsorbed PMMA remains on the substrate, even after washing with toluene (hereinafter called adsorbed sample). Neutron reflectometry revealed that the concerned structure consists of three layers: an inner layer (tightly bound on the substrate), a middle layer (bulk-like), and an outer layer (surface) in the adsorbed sample. When an adsorbed sample was exposed to toluene vapor, it became clear that, between the solid adsorption layer (which does not swell) and bulk-like swollen layer, there was a "buffer layer" that could sorb more toluene molecules than the bulk-like layer. This buffer layer was found not only in the adsorbed sample but also in the standard spin-cast PMMA thin films on the substrate. When the polymer chains were firmly adsorbed and immobilized on the Si substrate, the freedom of the possible structure right next to the tightly bound layer was reduced, which restricted the relaxation of the conformation of the polymer chain strongly. The "buffer layer" was manifested by the sorption of toluene with different scattering length density contrasts.
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Affiliation(s)
- Keisuke Shimokita
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, 466-8555, Japan.
| | - Katsuhiro Yamamoto
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, 466-8555, Japan.
| | - Noboru Miyata
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society, Tokai, Ibaraki, 319-1106, Japan.
| | - Yohei Nakanishi
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Motoki Shibata
- Office of Society-Academia Collaboration for Innovation, Kyoto University, Kyoto, 606-8501, Japan
| | - Mikihito Takenaka
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Norifumi L Yamada
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tokai, Ibaraki, 319-1106, Japan
| | - Hideki Seto
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tokai, Ibaraki, 319-1106, Japan
| | - Hiroyuki Aoki
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tokai, Ibaraki, 319-1106, Japan
- Materials and Life Science Division, J-PARC Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
| | - Tsukasa Miyazaki
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society, Tokai, Ibaraki, 319-1106, Japan.
- Office of Society-Academia Collaboration for Innovation, Kyoto University, Kyoto, 606-8501, Japan
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4
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Koike K, Kumaki J. Chain Movements at the Topmost Surface of Poly(methyl methacrylate) and Polystyrene Films Directly Evaluated by In Situ High-Temperature Atomic Force Microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:13707-13719. [PMID: 36318939 PMCID: PMC9671121 DOI: 10.1021/acs.langmuir.2c01788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/28/2022] [Indexed: 06/16/2023]
Abstract
The surfaces of polymeric materials are thermodynamically unstable, and the glass-transition temperature (Tg) is significantly lower than that in the bulk material. However, the mobility of the chains at the top of the surface has never been directly evaluated. In this study, the movements of the topmost chains of poly(methyl methacrylate) (PMMA) and polystyrene (PS) bulk films were observed in situ at high temperatures with atomic force microscopy in tapping mode. PMMA and PS chains started moving at ∼97 and ∼50 °C, respectively, which were slightly and significantly below the values of their bulk Tg (PMMA, 108 °C; PS, 104 °C), respectively. The activation energies of the apparent diffusion constants of PMMA and PS, derived by particle image velocimetry analysis, were 193 and 151 kJ mol-1, respectively, and reasonable for the glass transition. Movements of isolated PMMA chains deposited on a PMMA film by the Langmuir-Blodgett technique were also observed and confirmed to be essentially the same as those on the PMMA film surface.
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Affiliation(s)
- Kouki Koike
- Department of Organic Materials Science,
Graduate School of Organic Materials Science, Yamagata University, Yonezawa, Yamagata 992-8510, Japan
| | - Jiro Kumaki
- Department of Organic Materials Science,
Graduate School of Organic Materials Science, Yamagata University, Yonezawa, Yamagata 992-8510, Japan
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5
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Abstract
The lightweight and high-strength functional nanocomposites are important in many practical applications. Natural biomaterials with excellent mechanical properties provide inspiration for improving the performance of composite materials. Previous studies have usually focused on the bionic design of the material's microstructure, sometimes overlooking the importance of the interphase in the nanocomposite system. In this Perspective, we will focus on the construction and control of the interphase in confined space and the connection between the interphase and the macroscopic properties of the materials. We shall survey the current understanding of the critical size of the interphase and discuss the general rules of interphase formation. We hope to raise awareness of the interphase concept and encourage more experimental and simulation studies on this subject, with the aim of an optimal design and controllable preparation of polymer nanocomposite materials.
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Affiliation(s)
- Jin Huang
- Key
Laboratory of Bio-Inspired Smart Interfacial Science and Technology
of Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, People’s Republic
of China
- School
of Mechanical Engineering and Automation, Beihang University, Beijing 100191, People’s Republic
of China
| | - Jiajia Zhou
- South
China Advanced Institute for Soft Matter Science and Technology, School
of Molecular Science and Engineering, South
China University of Technology, Guangzhou 510640, People’s Republic of China
- Guangdong
Provincial Key Laboratory of Functional and Intelligent Hybrid Materials
and Devices, South China University of Technology, Guangzhou 510640, People’s Republic of China
- Email
for J.Z.:
| | - Mingjie Liu
- Key
Laboratory of Bio-Inspired Smart Interfacial Science and Technology
of Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, People’s Republic
of China
- Email for M.L.:
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6
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Bai L, Luo P, Yang X, Xu J, Kawaguchi D, Zhang C, Yamada NL, Tanaka K, Zhang W, Wang X. Enhanced Glass Transition Temperature of Thin Polystyrene Films Having an Underneath Cross-Linked Layer. ACS Macro Lett 2022; 11:210-216. [PMID: 35574771 DOI: 10.1021/acsmacrolett.1c00611] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Due to the importance of the interface in the segmental dynamics of supported macromolecule ultrathin films, the glass transition temperature (Tg) of polystyrene (PS) ultrathin films upon solid substrates modified with a cross-linked PS (CLPS) layer has been investigated. The results showed that the Tg of the thin PS films on a silica surface with a ∼5 nm cross-linked layer increased with reducing film thickness. Meanwhile, the increase in Tg of the thin PS films became more pronounced with increasing the cross-linking density of the layer. For example, a 20 nm thick PS film supported on CLPS with 1.8 kDa of cross-linking degree exhibited a ∼35 and ∼50 K increase in Tg compared to its bulk and that on neat SiO2 substrate, respectively. Such a large Tg elevation for the ultrathin PS films was attributed to the interfacial aggregation states in which chains diffused through nanolevel voids formed in the cross-linked layer to the SiO2-Si surface. In such a situation, the chains were topologically constrained in the cross-linked layer with less mobility. These results offer us the opportunity to tailor interfacial effects by changing the degree of cross-linking, which has great potential application in many polymer nanocomposites.
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Affiliation(s)
- Lu Bai
- Department of Chemistry, Key Laboratory of Surface and Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Pan Luo
- Department of Chemistry, Key Laboratory of Surface and Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Xudong Yang
- Department of Chemistry, Key Laboratory of Surface and Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Jianquan Xu
- Department of Chemistry, Key Laboratory of Surface and Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Daisuke Kawaguchi
- Department of Applied Chemistry and Center for Polymer Interface and Molecular Adhesion Science, Kyushu University, Fukuoka 819-0395, Japan
| | - Cuiyun Zhang
- Department of Chemistry, Key Laboratory of Surface and Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Norifumi L. Yamada
- Neutron Science Division, Institute for Materials Structure Science, High Energy, Acceleration Research Organization, Naka, Ibaraki 319-1106, Japan
| | - Keiji Tanaka
- Department of Applied Chemistry and Center for Polymer Interface and Molecular Adhesion Science, Kyushu University, Fukuoka 819-0395, Japan
| | - Wei Zhang
- Department of Chemistry, Key Laboratory of Surface and Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Xinping Wang
- Department of Chemistry, Key Laboratory of Surface and Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
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7
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Aoki H, Liu Y, Yamashita T. Deep learning approach for an interface structure analysis with a large statistical noise in neutron reflectometry. Sci Rep 2021; 11:22711. [PMID: 34811432 PMCID: PMC8608885 DOI: 10.1038/s41598-021-02085-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 11/08/2021] [Indexed: 11/09/2022] Open
Abstract
Neutron reflectometry (NR) allows us to probe into the structure of the surfaces and interfaces of various materials such as soft matters and magnetic thin films with a contrast mechanism dependent on isotopic and magnetic states. The neutron beam flux is relatively low compared to that of other sources such as synchrotron radiation; therefore, there has been a strong limitation in the time-resolved measurement and further advanced experiments such as surface imaging. This study aims at the development of a methodology to enable the structural analysis by the NR data with a large statistical error acquired in a short measurement time. The neural network-based method predicts the true NR profile from the data with a 20-fold lower signal compared to that obtained under the conventional measurement condition. This indicates that the acquisition time in the NR measurement can be reduced by more than one order of magnitude. The current method will help achieve remarkable improvement in temporally and spatially resolved NR methods to gain further insight into the surface and interfaces of materials.
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Affiliation(s)
- Hiroyuki Aoki
- Materials and Life Science Division, J-PARC Center, Japan Atomic Energy Agency, 2-4, Shirakata, Tokai, Ibaraki, 319-1195, Japan. .,Institute of Materials Structure Science, High Energy Accelerator Research Organization, 203-1, Shirakata, Tokai, Ibaraki, 319-1106, Japan.
| | - Yuwei Liu
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, 203-1, Shirakata, Tokai, Ibaraki, 319-1106, Japan
| | - Takashi Yamashita
- AdvanceSoft, Corp., 4-3, Kandasurugadai, Chiyoda, Tokyo, 101-0062, Japan
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8
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Monnier X, Colmenero J, Wolf M, Cangialosi D. Reaching the Ideal Glass in Polymer Spheres: Thermodynamics and Vibrational Density of States. PHYSICAL REVIEW LETTERS 2021; 126:118004. [PMID: 33798388 DOI: 10.1103/physrevlett.126.118004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 12/04/2020] [Accepted: 02/17/2021] [Indexed: 06/12/2023]
Abstract
The existence of an ideal glass and the resolution to the Kauzmann paradox is a long-standing open question in materials science. To address this problem, we exploit the ability of glasses with large interfacial area to access low energy states. We submit aggregates of spheres of a polymeric glass former to aging well below their glass transition temperature, T_{g}; and characterize their thermodynamic state by calorimetry, and the vibrational density of state (VDOS) by inelastic neutron scattering (INS). We show that, when aged at appropriate temperatures, glassy spheres attain a thermodynamic state corresponding to an ideal glass in time scales of about one day. In this state, the boson peak, underlying the deviation from the Debye level of the VDOS, is essentially suppressed. Our results are discussed in the framework of the link between the macroscopic thermodynamic state of glasses and their vibrational properties.
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Affiliation(s)
- Xavier Monnier
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 San Sebastián, Spain
| | - Juan Colmenero
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 San Sebastián, Spain
- Departamento de Fisica de Materiales (UPV/EHU), Apartado 1072, 20080 San Sebastián, Spain
- Centro de Fisica de Materiales (CSIC-UPV/EHU) Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
| | - Marcel Wolf
- Heinz Maier-Leibnitz Zentrum (MLZ), Lichtenbergstrasse 1 85747, Garching, Germany
| | - Daniele Cangialosi
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 San Sebastián, Spain
- Centro de Fisica de Materiales (CSIC-UPV/EHU) Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
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9
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Aoki H, Ogawa H, Takenaka M. Neutron Reflectometry Tomography for Imaging and Depth Structure Analysis of Thin Films with In-Plane Inhomogeneity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:196-203. [PMID: 33346671 DOI: 10.1021/acs.langmuir.0c02744] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Neutron reflectometry (NR) has been used for the depth structure analysis of materials at the surface and interface with a sub-nanometric resolution. Conventional NR provides averaged information for an area larger than several square centimeters; therefore, it cannot be applied to an interface with an in-plane inhomogeneity. In this study, the NR imaging of the in-plane structure of polymer thin films was achieved. The tomographic reconstruction of the spatially resolved NR profiles obtained by a sheet-shaped neutron beam provided a two-dimensional image of the in-plane interface morphology. The depth distribution of the neutron scattering length density was obtained by analyzing the position-dependent NR profile at a local area less than 0.1 mm2. The current NR tomography method enables NR measurements for an interface with an inhomogeneous structure. It also provides information on the three-dimensional distribution of the atomic composition near the surface and interfaces for various materials.
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Affiliation(s)
- Hiroyuki Aoki
- Materials and Life Science Division, J-PARC Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki 319-1195, Japan
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, 203-1 Shirakata, Tokai, Ibaraki 319-1106, Japan
| | - Hiroki Ogawa
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Mikihito Takenaka
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
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10
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Hynes EL, Gutfreund P, Parnell AJ, Higgins AM. Liquid-liquid equilibrium in polymer-fullerene mixtures; an in situ neutron reflectivity study. SOFT MATTER 2020; 16:3727-3739. [PMID: 32232256 DOI: 10.1039/c9sm02337b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The composition profiles of a series of model polystyrene/fullerene bilayers are measured, before, during and after thermal annealing, using in situ neutron reflectometry. In combination with grazing-incidence X-ray diffraction measurements, these experiments, which quantify layer compositions as a function of molecular weight using changes in both scattering length density and layer thickness, extend and corroborate recent measurements on ex situ annealed samples and demonstrate that the composition profiles rapidly formed in these systems correspond to two co-existing liquid-liquid phases in thermodynamic equilibrium. The measurements also demonstrate a clear and systematic onset temperature for diffusion of the fullerenes into the PS layer that correlates with the known glass-transition temperatures of both the polymer (as a function of molecular weight) and the fullerene, revealing that the molecular mobility of the fullerenes in these systems is controlled by the intrinsic mobility of the fullerenes themselves and the ability of the polymer to plasticise the fullerenes at the interface. Over the temperature range investigated (up to 145 °C), measurements of equilibrated composition profiles as a function of temperature (during gradual cooling) reveal no significant changes in composition profile, other than those associated with the known thermal expansion/contraction of polystyrene thin-films.
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Affiliation(s)
- E L Hynes
- College of Engineering, Swansea University, Bay Campus, Fabian Way, Swansea SA1 8EN, Wales, UK.
| | - P Gutfreund
- Institut Laue-Langevin, 71 avenue des Martyrs, 38000 Grenoble, France
| | - A J Parnell
- Department of Physics and Astronomy, The University of Sheffield, Sheffield S3 7RH, UK
| | - A M Higgins
- College of Engineering, Swansea University, Bay Campus, Fabian Way, Swansea SA1 8EN, Wales, UK.
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11
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Taguchi K, Miyamoto Y, Toda A. Molecular Weight Dependence of Crystal Growth in Isotactic Polystyrene Ultrathin Films. ACS Macro Lett 2019; 8:1227-1232. [PMID: 35651162 DOI: 10.1021/acsmacrolett.9b00516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this paper, we report the molecular weight dependence of the crystal growth of isotactic polystyrene from 10 nm ultrathin films. The growth rate and characteristic length of the branching morphology of a crystal grown in 10 nm ultrathin films change depending on the molecular weight of the sample. Analysis of the molecular weight dependence according to the theory of growth front instability reveals that the diffusion coefficient of molecular chains in ultrathin films around branching crystals scales with the molecular weight as Mw-1.4 for samples with weights higher than the critical molecular weight for the entanglement of polystyrene. This result indicates that the polymer chains in the depletion zone around the crystals diffuse in quasi-two dimensions through the reptational motion modified on an attractive substrate.
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Affiliation(s)
- Ken Taguchi
- Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Yoshihisa Miyamoto
- Graduate School of Human and Environmental Studies, Kyoto University, Yoshida-nihonmatsu-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Akihiko Toda
- Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
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12
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Umetsu R, Kumaki J. Fabrication of a Polymer Molecularly Flat Substrate by Thermal Nanoimprinting and AFM Observation of Polymer Chains Deposited on It. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01280] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ryota Umetsu
- Department of Organic Materials Science, Graduate School of Organic Materials Science, Yamagata University,
Yonezawa, Yamagata 992-8510, Japan
| | - Jiro Kumaki
- Department of Organic Materials Science, Graduate School of Organic Materials Science, Yamagata University,
Yonezawa, Yamagata 992-8510, Japan
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13
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Liu Y, Sakurai K. Thickness Changes in Temperature-Responsive Poly( N-isopropylacrylamide) Ultrathin Films under Ambient Conditions. ACS OMEGA 2019; 4:12194-12203. [PMID: 31460334 PMCID: PMC6681975 DOI: 10.1021/acsomega.9b01350] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/01/2019] [Indexed: 06/10/2023]
Abstract
In this paper, we report detailed experimental observations of unusual changes in the thickness of solid poly(N-isopropylacrylamide) (PNIPAM) ultrathin films, which are well known to have temperature-responsive hydrophilic-hydrophobic switching properties. To date, a number of studies have been carried out on the bulk and the brush forms of PNIPAM in contact with liquid water, as well as in highly humid environments, and, recently, these ultrathin films have been preliminarily shown to exhibit temperature responses even under low-humidity, ambient conditions. In this work, the thicknesses of ultrathin PNIPAM films in a temperature/moisture-controlled sample stage were monitored continuously using multichannel X-ray reflectometry. At room temperature, the sample thickness showed an unexpected increase after thermal treatment at 70 °C for 3 h. In the temperature cycle between 15 and 60 °C, heating and cooling resulted in some clear differences. During cooling, initially, the thickness was almost constant but began to increase when the temperature exceeded 33 °C, which corresponds to the lower critical solution temperature (LCST). This observation indicates that the PNIPAM ultrathin film is sensitive to the small amounts of water contained in the air, even under ambient, low-humidity conditions. On the other hand, during heating run from 15 to 60 °C, the humidity dependence was monotonic, and no specific changes in the PNIPAM films were observed at around the LCST. By studying the humidity dependence, we found that the hydrophilic and hydrophobic states of the PNIPAM ultrathin film exhibit different temperature dependence behaviors. In addition, we found that swelling takes place even under low-moisture conditions. To understand the difference in the thickness changes observed on cooling and heating further, some models considering the effect of the boundary conditions in the polymer ultrathin film system were considered. In the case of the ultrathin film, the hydrophilic/hydrophobic switching property occurred only in the surface layer, which dominated the absorption of water molecules from air. In contrast, the interface layer was time-stable and provided an escape route for water molecules during heating.
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Affiliation(s)
- Yuwei Liu
- University
of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-0006, Japan
- National
Institute for Materials Science, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047, Japan
| | - Kenji Sakurai
- University
of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-0006, Japan
- National
Institute for Materials Science, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047, Japan
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14
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Liu Y, Sakurai K. Slow dynamics in thermal expansion of polyvinyl acetate thin film with interface layer. Polym J 2019. [DOI: 10.1038/s41428-019-0211-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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Thermal expansion behavior of thin films expanding freely on water surface. Sci Rep 2019; 9:7071. [PMID: 31068646 PMCID: PMC6506477 DOI: 10.1038/s41598-019-43592-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 04/24/2019] [Indexed: 11/09/2022] Open
Abstract
Coefficient of thermal expansion (CTE) for thin film has been measured only from change in thickness because thin film has to be constrained on a solid substrate. However, thin film CTE shows different values depending on the supporting solid substrate. Here, a novel measurement method is suggested to quantitatively measure the in-plane thermal expansion of thin films floating on a water surface. In-plane thermal expansion of thin films on water surface is achieved by heating the water. The CTE is measured through a digital image correlation (DIC) technique. The DIC tracks displacement marks deposited on the film surface, and the in-plane thermal strain is defined as the change in distance between the patterns. The method can be applied to measure the CTE of polymer, metal, and graphene with a thickness ranging from a micrometer to one-atom-thickness. The in-plane thermal expansion of the polystyrene (PS) thin film decreased as the film thickness decreased. The negative CTE of graphene is also successfully explored without any substrate effects or complicated calculations. The CTE measurement method can provide understanding of the intrinsic thermal expansion behavior of thin films including emerging two-dimensional materials.
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16
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Chain dynamics in spin-coated films of poly(methyl methacrylate) in a solvent annealing process. Polym J 2019. [DOI: 10.1038/s41428-019-0171-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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17
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Liu Y, Sakurai K. Uniaxial Negative Thermal Expansion of Polyvinyl Acetate Thin Film. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:11272-11280. [PMID: 30133290 DOI: 10.1021/acs.langmuir.8b01607] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The present paper reports some experimental observations of reproducible uniaxial negative thermal expansion (u-NTE) in an amorphous polyvinyl acetate (PVAc) ultrathin film. It has been found that the mechanism of the phenomena is different from latest reports on so-called NTE in crystal or other topological materials. It is known that PVAc exhibits glass transition at around 31 °C. During cooling from the high-temperature side, one can observe the decrease of the thickness by monitoring interference fringes in the X-ray reflectivity curve as a function of temperature. Across the glass transition, however, the thickness starts to increase, instead of reducing. In the heating process, the thickness decreases as long as the temperature is lower than that for glass transition ( Tg). In the present research, such changes in thickness during repeated heating/cooling cycles have been studied systematically. To discuss the mechanism, dependence on film thickness has been investigated as well. It has been found that the present phenomena are well explained as u-NTE, which induces reduction and increase of thickness ( z-direction) just by thermal expansion and shrinking in x- y directions, respectively. This would be caused and enhanced by the growth of a mechanically hard, high-density layer near the interface to the surface of hydrophilic silicon dioxide. The structural change during heating/cooling cycles is discussed in detail.
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Affiliation(s)
- Yuwei Liu
- University of Tsukuba , 1-1-1, Tennodai , Tsukuba , Ibaraki 305-0006 , Japan
- National Institute for Materials Science , 1-2-1, Sengen , Tsukuba , Ibaraki 305-0047 , Japan
| | - Kenji Sakurai
- University of Tsukuba , 1-1-1, Tennodai , Tsukuba , Ibaraki 305-0006 , Japan
- National Institute for Materials Science , 1-2-1, Sengen , Tsukuba , Ibaraki 305-0047 , Japan
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18
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McKenzie I, Chai Y, Cortie DL, Forrest JA, Fujimoto D, Karner VL, Kiefl RF, Levy CDP, MacFarlane WA, McFadden RML, Morris GD, Pearson MR, Zhu S. Direct measurements of the temperature, depth and processing dependence of phenyl ring dynamics in polystyrene thin films by β-detected NMR. SOFT MATTER 2018; 14:7324-7334. [PMID: 29796450 DOI: 10.1039/c8sm00812d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
There is indirect evidence that the dynamics of a polymer near a free surface are enhanced compared with the bulk but there are few studies of how dynamics varies with depth. β-Detected nuclear spin relaxation of implanted 8Li+ has been used to directly probe the temperature and depth dependence of the γ-relaxation mode, which is due to phenyl rings undergoing restricted rotation, in thin films of atactic deuterated polystyrene (PS-d8) and determine how the depth dependence of dynamics is affected by sample processing, such as annealing, floating on water and the inclusion of a surfactant, and by the presence of a buried interface. The activation energy for the γ-relaxation process is lower near the free surface. Annealing the PS-d8 films and then immersing in water to mimic the floating procedure used to transfer films had negligible effects on the thickness of the region near the free surface with enhanced mobility. Measurements on a bilayer film indicate enhanced phenyl ring dynamics near the buried interface compared with a single film at the same depth. PS-d8 films annealed with the surfactant sodium dodecyl sulfate (SDS) deposited on the surface show enhanced dynamics in the bulk compared with a pure PS-d8 film and a PS-d8 film where the SDS was washed away. There is less contrast between the surface and bulk in the SDS-treated sample, which could account for the elimination of the Tg confinement effect observed in films containing SDS [Chen and Torkelson, Polymer, 2016, 87, 226].
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19
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Sugimoto S, Inutsuka M, Kawaguchi D, Tanaka K. Reorientation Kinetics of Local Conformation of Polyisoprene at Substrate Interface. ACS Macro Lett 2018; 7:85-89. [PMID: 35610922 DOI: 10.1021/acsmacrolett.7b00927] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The performance of a polymer composite material, in which inorganic fillers are dispersed, is closely related to the aggregation states and dynamics of polymer chains at the interface with the filler. In this study, the local conformation of polyisoprene (PI) at a quartz substrate interface was studied as a model system for the rubber/filler composite material. PI films were prepared from a toluene solution onto quartz substrates by a spin-coating method. Sum-frequency generation spectroscopy revealed that the local conformation of PI chains at the quartz interface depended on the spinning rate. The tilt angle of methyl groups increased with the rotational speed, probably due to the centrifugal force applied to chains and probably also the evaporation rate of the solvent during the solidification process. This result indicates that the interfacial orientation of PI chains can remain even at room temperature, which is 87 K higher than the bulk glass transition temperature (Tgb). The interfacial orientation disappeared at a temperature approximately 120 K higher than Tgb.
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Affiliation(s)
- Shin Sugimoto
- Department
of Automotive Science, ‡Department of Applied Chemistry, §Education Center for
Global Leaders in Molecular Systems for Devices, and ∥International Institute for Carbon-Neutral
Energy Research (WPI-I2CNER), Kyushu University, Fukuoka, 819-0395, Japan
| | - Manabu Inutsuka
- Department
of Automotive Science, ‡Department of Applied Chemistry, §Education Center for
Global Leaders in Molecular Systems for Devices, and ∥International Institute for Carbon-Neutral
Energy Research (WPI-I2CNER), Kyushu University, Fukuoka, 819-0395, Japan
| | - Daisuke Kawaguchi
- Department
of Automotive Science, ‡Department of Applied Chemistry, §Education Center for
Global Leaders in Molecular Systems for Devices, and ∥International Institute for Carbon-Neutral
Energy Research (WPI-I2CNER), Kyushu University, Fukuoka, 819-0395, Japan
| | - Keiji Tanaka
- Department
of Automotive Science, ‡Department of Applied Chemistry, §Education Center for
Global Leaders in Molecular Systems for Devices, and ∥International Institute for Carbon-Neutral
Energy Research (WPI-I2CNER), Kyushu University, Fukuoka, 819-0395, Japan
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20
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Cangialosi D. Glass Transition and Physical Aging of Confined Polymers Investigated by Calorimetric Techniques. RECENT ADVANCES, TECHNIQUES AND APPLICATIONS 2018. [DOI: 10.1016/b978-0-444-64062-8.00013-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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21
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Burroughs MJ, Christie D, Gray LAG, Chowdhury M, Priestley RD. 21st Century Advances in Fluorescence Techniques to Characterize Glass‐Forming Polymers at the Nanoscale. MACROMOL CHEM PHYS 2017. [DOI: 10.1002/macp.201700368] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Mary J. Burroughs
- Department of Chemical and Biological Engineering Princeton University Princeton NJ 08544 USA
| | - Dane Christie
- Department of Chemical and Biological Engineering Princeton University Princeton NJ 08544 USA
| | - Laura A. G. Gray
- Department of Chemical and Biological Engineering Princeton University Princeton NJ 08544 USA
| | - Mithun Chowdhury
- Department of Chemical and Biological Engineering Princeton University Princeton NJ 08544 USA
| | - Rodney D. Priestley
- Department of Chemical and Biological Engineering Princeton Institute for the Science and Technology of Materials Princeton University Princeton NJ 08544 USA
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22
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Vogt BD. Mechanical and viscoelastic properties of confined amorphous polymers. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/polb.24529] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Bryan D. Vogt
- Department of Polymer Engineering; University of Akron; Akron Ohio 44325
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23
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Xu J, Zhang Y, Zhou H, Hong Y, Zuo B, Wang X, Zhang L. Probing the Utmost Distance of Polymer Dynamics Suppression by a Substrate by Investigating the Diffusion of Fluorinated Tracer-Labeled Polymer Chains. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b01158] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Jianquan Xu
- Department of Chemistry,
Key Laboratory of Advanced Textile Materials and Manufacturing Technology
of the Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Yizhi Zhang
- Department of Chemistry,
Key Laboratory of Advanced Textile Materials and Manufacturing Technology
of the Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Hao Zhou
- Department of Chemistry,
Key Laboratory of Advanced Textile Materials and Manufacturing Technology
of the Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Yongming Hong
- Department of Chemistry,
Key Laboratory of Advanced Textile Materials and Manufacturing Technology
of the Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Biao Zuo
- Department of Chemistry,
Key Laboratory of Advanced Textile Materials and Manufacturing Technology
of the 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 the Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. 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, P. R. China
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24
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Hayashi T, Segawa K, Sadakane K, Fukao K, Yamada NL. Interfacial interaction and glassy dynamics in stacked thin films of poly(methyl methacrylate). J Chem Phys 2017; 146:203305. [PMID: 28571347 DOI: 10.1063/1.4974835] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Neutron reflectivity and dielectric permittivity of alternately stacked thin films of protonated and deuterated poly(methyl methacrylate) were measured to elucidate a correlation between the time evolution of the interfacial structure and the segmental dynamics in the stacked thin polymer films during isothermal annealing above the glass transition temperature. The roughness at the interface between two thin layers increases with the annealing time, whereas the relaxation rate and strength of the α-process decrease with an increase in the annealing time. A strong correlation between the time evolution of the interfacial structure and the dynamics of the α-process during annealing could be observed using neutron reflectivity and dielectric relaxation measurements.
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Affiliation(s)
- Tatsuhiko Hayashi
- Department of Physics, Ritsumeikan University, Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan
| | - Kenta Segawa
- Department of Physics, Ritsumeikan University, Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan
| | - Koichiro Sadakane
- Department of Physics, Ritsumeikan University, Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan
| | - Koji Fukao
- Department of Physics, Ritsumeikan University, Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan
| | - Norifumi L Yamada
- Neutron Science Division, Institute for Materials Structure Science, High Energy Acceleration Research Organization, 203-1 Shirakata, Tokai, Naka 319-1106, Japan
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25
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Boucher VM, Cangialosi D, Alegría A, Colmenero J. Reaching the ideal glass transition by aging polymer films. Phys Chem Chem Phys 2017; 19:961-965. [DOI: 10.1039/c6cp07139b] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
By aging, we draw glassy polymer films to a thermodynamic state, the ideal glass, with the entropy of the crystal.
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Affiliation(s)
| | | | - Angel Alegría
- Centro de Física de Materiales
- 20018 San Sebastián
- Spain
- Departamento de Física de Materiales (UPV/EHU)
- 20080 San Sebastián
| | - Juan Colmenero
- Centro de Física de Materiales
- 20018 San Sebastián
- Spain
- Departamento de Física de Materiales (UPV/EHU)
- 20080 San Sebastián
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26
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Shimomura S, Inutsuka M, Yamada NL, Tanaka K. Unswollen layer of cross-linked polyisoprene at the solid interface. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.07.047] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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27
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Pratt FL, Lancaster T, Baker PJ, Blundell SJ, Prokscha T, Morenzoni E, Suter A, Assender HE. Nanoscale depth-resolved polymer dynamics probed by the implantation of low energy muons. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.07.078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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28
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Liu D, Qin H, Zhang J, Wang T. Thickness-dependent glass transition temperature and charge mobility in cross-linked polyfluorene thin films. Phys Rev E 2016; 94:052503. [PMID: 27967096 DOI: 10.1103/physreve.94.052503] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Indexed: 06/06/2023]
Abstract
We report thickness-dependent glass transition temperature (T_{g}) and charge mobility in cross-linked thin films made of conjugated polymer poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine) (TFB). Monotonic T_{g} depressions with reducing film thickness in thermally and UV cross-linked TFB thin films supported on Si-SiOx substrates are observed through ellipsometry measurements, suggesting that a surface mobile layer with enhanced chain dynamics still exists in cross-linked TFB thin films, even with a high cross-linking percentage. Data fitting using a three-layer model shows that the T_{g} in the interface, bulk and surface layer both increases with increasing cross-linking, while the thickness of the interface and surface layer increases and reduces, respectively. Cross-linking of TFB thin film generates traps that hinder charge transport and consequently reduce charge mobility. The charge mobility converges in thick (>140 nm) and thin (<40 nm) TFB films but shows strong thickness dependence in between, reducing from 4.0×10^{-4}cm^{2}/Vs in a 180-nm film to 0.1×10^{-4}cm^{2}/Vs in a 20-nm thin film.
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Affiliation(s)
- Dan Liu
- School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China
| | - Hui Qin
- School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China
| | - Jinghui Zhang
- School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China
| | - Tao Wang
- School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China
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29
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Stiffness of thin, supported polystyrene films: Free-surface, substrate, and confinement effects characterized via self-referencing fluorescence. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.07.042] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Shin Y, Lee H, Lee W, Ryu DY. Glass Transition and Thermal Expansion Behavior of Polystyrene Films Supported on Polystyrene-Grafted Substrates. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00458] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yeseul Shin
- Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Hoyeon Lee
- Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Wooseop Lee
- Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Du Yeol Ryu
- Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
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31
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Tan AW, Torkelson JM. Poly(methyl methacrylate) nanotubes in AAO templates: Designing nanotube thickness and characterizing the T-confinement effect by DSC. POLYMER 2016. [DOI: 10.1016/j.polymer.2015.11.054] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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32
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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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33
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Evans CM, Kim S, Roth CB, Priestley RD, Broadbelt LJ, Torkelson JM. Role of neighboring domains in determining the magnitude and direction of Tg-confinement effects in binary, immiscible polymer systems. POLYMER 2015. [DOI: 10.1016/j.polymer.2015.10.059] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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34
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Ohisa S, Pu YJ, Yamada NL, Matsuba G, Kido J. Molecular Interdiffusion between Stacked Layers by Solution and Thermal Annealing Processes in Organic Light Emitting Devices. ACS APPLIED MATERIALS & INTERFACES 2015; 7:20779-20785. [PMID: 26331696 DOI: 10.1021/acsami.5b05818] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In organic light emitting devices (OLEDs), interfacial structures between multilayers have large impacts on the characteristics of OLEDs. Herein, we succeeded in revealing the interdiffusion in solution processed and thermal annealed OLEDs by neutron reflectometry. We investigated interfaces between a polymer under layer and small molecules upper layer. The small molecules diffused into the swollen polymer layer during the interfacial formation by the solution process, but the polymer did not diffuse into the small molecules layer. At temperatures close to the glass transition temperatures of the materials, asymmetric molecular diffusion was observed. We elucidated the effects of the interdiffusion on the characteristics of OLEDs. Partially mixing the interface improved the current efficiencies due to suppressed triplet-polaron quenching at the interface. Controlling and understanding the interfacial structures of the miultilayers will be more important to improve the OLED characteristics.
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Affiliation(s)
- Satoru Ohisa
- Department of Organic Device Engineering, Yamagata University , 4-3-16 Johnan, Yonezawa, Yamagata 992-8510, Japan
| | - Yong-Jin Pu
- Department of Organic Device Engineering, Yamagata University , 4-3-16 Johnan, Yonezawa, Yamagata 992-8510, Japan
| | - Norifumi L Yamada
- Institute of Material Structure Science, High-Energy Accelerator Research Organization (KEK) , 203-1 Shirakata, Tokai, Naka 319-1106, Japan
| | - Go Matsuba
- Department of Polymer Science and Engineering, Yamagata University , 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Junji Kido
- Department of Organic Device Engineering, Yamagata University , 4-3-16 Johnan, Yonezawa, Yamagata 992-8510, Japan
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35
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Lee H, Jo S, Hirata T, Yamada NL, Tanaka K, Kim E, Ryu DY. Interpenetration of chemically identical polymer onto grafted substrates. POLYMER 2015. [DOI: 10.1016/j.polymer.2015.07.054] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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36
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Kanaya T, Ogawa H, Kishimoto M, Inoue R, Suter A, Prokscha T. Distribution of glass transition temperatures Tg in polystyrene thin films as revealed by low-energy muon spin relaxation: A comparison with neutron reflectivity results. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:022604. [PMID: 26382423 DOI: 10.1103/physreve.92.022604] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Indexed: 06/05/2023]
Abstract
In a previous paper [Phys. Rev. E 83, 021801 (2011)] we performed neutron reflectivity (NR) measurements on a five-layer polystyrene (PS) thin film consisting of alternatively stacked deuterated polystyrene (dPS) and hydrogenated polystyrene (hPS) layers (dPS/hPS/dPS/hPS/dPS, ∼100 nm thick) on a Si substrate to reveal the distribution of Tg along the depth direction. Information on the Tg distribution is very useful to understand the interesting but unusual properties of polymer thin films. However, one problem that we have to clarify is if there are effects of deuterium labeling on Tg or not. To tackle the problem we performed low-energy muon spin relaxation (μSR) measurements on the above-mentioned deuterium-labeled five-layer PS thin film as well as dPS and hPS single-layer thin films ∼100 nm thick as a function of muon implantation energy. It was found that the deuterium labeling had no significant effects on the Tg distribution, guaranteeing that we can safely discuss the unusual thin film properties based on the Tg distribution revealed by NR on the deuterium-labeled thin films. In addition, the μSR result suggested that the higher Tg near the Si substrate is due to the strong orientation of phenyl rings.
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Affiliation(s)
- Toshiji Kanaya
- Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611-0011, Japan
| | - Hiroki Ogawa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611-0011, Japan
| | - Mizuki Kishimoto
- Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611-0011, Japan
| | - Rintaro Inoue
- Research Reactor Institute, Kyoto University, Kumatori, Sennan-gun, Osaka-fu 590-0494, Japan
| | - Andreas Suter
- Laboratory for Muon-Spin Spectroscopy, Swiss Muon Source SµS, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Thomas Prokscha
- Laboratory for Muon-Spin Spectroscopy, Swiss Muon Source SµS, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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37
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Wu R, Qiu X, Zhang T, Fu K, Yang X. Atomistic Molecular Insight into the Time Dependence of Polymer Glass Transition. J Phys Chem B 2015; 119:9959-69. [DOI: 10.1021/acs.jpcb.5b03066] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rongliang Wu
- College
of Material Science and Engineering, State Key Laboratory for Modification
of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620, China
| | - Xinlong Qiu
- College
of Material Science and Engineering, State Key Laboratory for Modification
of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620, China
| | - Tianyi Zhang
- Department
of Applied Mathematics, School of Mathematical Science, Fudan University, Shanghai 200433, China
| | - Kangyu Fu
- College
of Material Science and Engineering, State Key Laboratory for Modification
of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620, China
| | - Xiaozhen Yang
- Beijing National
Laboratory for Molecular Sciences, State Key Laboratory of Polymer
Science and Engineering, Joint Laboratory of Polymer Science and Materials, Beijing 100190, China
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38
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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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39
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Zhang L, Torkelson JM. Influence of initiator fragments as chain ends on the Tg-confinement effect and dewetting of thin films of ultralow molecular weight polymer. POLYMER 2015. [DOI: 10.1016/j.polymer.2015.03.056] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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40
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McKenzie I, Daley CR, Kiefl RF, Levy CDP, MacFarlane WA, Morris GD, Pearson MR, Wang D, Forrest JA. Enhanced high-frequency molecular dynamics in the near-surface region of polystyrene thin films observed with β-NMR. SOFT MATTER 2015; 11:1755-1761. [PMID: 25605007 DOI: 10.1039/c4sm02245a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
β-detected nuclear spin relaxation of (8)Li(+) has been used to probe the depth dependence of molecular dynamics in high- and low-molecular-weight deuterated polystyrene. The average nuclear spin-lattice relaxation rate, 1/T(avg)(1), is a measure of the spectral density of the polymer motion at the Larmor frequency (41 MHz at 6.55 T). In both samples, 1/T(avg)(1) is depth independent below ∼200 K but above this temperature it decreases approximately exponentially with distance from the free surface, returning to bulk behavior for depths greater than ∼10 nm. This is direct evidence for a region near the free surface with enhanced molecular dynamics compared with the bulk. The effective thickness of the surface region increases with increasing temperature and is finite even above the glass transition. These results present challenges for the current understanding of dynamics near the surface of polymer glasses.
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41
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Jiang N, Sendogdular L, Di X, Sen M, Gin P, Endoh MK, Koga T, Akgun B, Dimitriou M, Satija S. Effect of CO2 on a Mobility Gradient of Polymer Chains near an Impenetrable Solid. Macromolecules 2015. [DOI: 10.1021/ma502591x] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | | | - Maya K. Endoh
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Tadanori Koga
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Bulent Akgun
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
- Department of Chemistry, Bogazici University, Bebek, Istanbul 34342, Turkey
| | - Michael Dimitriou
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Sushil Satija
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
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42
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Ye C, Wiener CG, Tyagi M, Uhrig D, Orski SV, Soles CL, Vogt BD, Simmons DS. Understanding the Decreased Segmental Dynamics of Supported Thin Polymer Films Reported by Incoherent Neutron Scattering. Macromolecules 2015. [DOI: 10.1021/ma501780g] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Changhuai Ye
- Department
of Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
| | - Clinton G. Wiener
- Department
of Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
| | - Madhusudan Tyagi
- Department
of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - David Uhrig
- Center
for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | | | | | - Bryan D. Vogt
- Department
of Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
| | - David S. Simmons
- Department
of Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
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43
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Pye JE, Roth CB. Above, below, and in-between the two glass transitions of ultrathin free-standing polystyrene films: Thermal expansion coefficient and physical aging. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/polb.23635] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Justin E. Pye
- Department of Physics; Emory University; Atlanta Georgia 30322
| | - Connie B. Roth
- Department of Physics; Emory University; Atlanta Georgia 30322
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44
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Methacrylate-based polymer films useful in lithographic applications exhibit different glass transition temperature-confinement effects at high and low molecular weight. POLYMER 2014. [DOI: 10.1016/j.polymer.2014.01.031] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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45
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McKenzie I, Salman Z, Giblin SR, Han YY, Leach GW, Morenzoni E, Prokscha T, Suter A. Polymer dynamics near the surface and in the bulk of poly(tetrafluoroethylene) probed by zero-field muon-spin-relaxation spectroscopy. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:022605. [PMID: 25353500 DOI: 10.1103/physreve.89.022605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Indexed: 06/04/2023]
Abstract
The results of many experiments on polymers such as polystyrene indicate that the polymer chains near a free surface exhibit enhanced dynamics when compared with the bulk. We have investigated whether this is the case for poly(tetrafluoroethylene) (PTFE) by using zero-field muon-spin-relaxation spectroscopy to characterize a local probe, the F-Mu(+)-F state, which forms when spin-polarized positive muons are implanted in PTFE. Low-energy muons (implantation energies from 2.0 to 23.0 keV) were used to study the F-Mu(+)-F state between ∼ 23 and 191 nm from the free surface of PTFE. Measurements were also made with surface muons (4.1 MeV) where the mean implantation depth is on the order of ∼ 0.6 mm. The relaxation rate of the F-Mu(+)-F state up to ∼ 150 K was found to be significantly higher for muons implanted at 2.0 keV than for higher implantation energies, which suggests that the polymer chains in a region on the order of a few tens of nanometers from the free surface are more mobile than those in the bulk.
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Affiliation(s)
- Iain McKenzie
- Centre for Molecular and Materials Science, TRIUMF, Vancouver, British Columbia, Canada V6T 2A3 and Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - Zaher Salman
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Sean R Giblin
- School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA, United Kingdom
| | - Yun Yu Han
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - Gary W Leach
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - Elvezio Morenzoni
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Thomas Prokscha
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Andreas Suter
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
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46
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Inoue R, Nakamura M, Matsui K, Kanaya T, Nishida K, Hino M. Distribution of glass transition temperature in multilayered poly(methyl methacrylate) thin film supported on a Si substrate as studied by neutron reflectivity. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:032601. [PMID: 24125286 DOI: 10.1103/physreve.88.032601] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Indexed: 05/26/2023]
Abstract
We studied the distribution of glass transition temperature (Tg) through neutron reflectivity in a poly(methyl methacrylate) (PMMA) thin film supported on a silicon substrate with a five-layered PMMA thin film consisting of deuterated-PMMA and hydrogenated-PMMA. The depth distribution of Tg was successfully observed in the PMMA thin film. Compared to the previously reported distribution of Tg in a polystyrene thin film, the presence of a long-range interfacial effect, supposedly caused by an interaction between PMMA and the substrate, is considered to be responsible for the differences in both the distribution of Tg and the thickness dependence of Tg in both polymers. Therefore, it is expected that the thickness dependence of Tg reported for single-layered polymer thin films can, in principle, be understood from the viewpoint of the difference in the depth distribution of Tg.
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Affiliation(s)
- Rintaro Inoue
- Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611-0011, Japan
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47
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Evans CM, Deng H, Jager WF, Torkelson JM. Fragility is a Key Parameter in Determining the Magnitude of Tg-Confinement Effects in Polymer Films. Macromolecules 2013. [DOI: 10.1021/ma401017n] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
| | | | - Wolter F. Jager
- Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628
BL Delft, The Netherlands
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48
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Aoki H, Mori K, Takahashi T, Ito S. Quantitative analysis of end-to-end distance of single polymer chain in ultra-thin film by super-resolution fluorescence imaging. Chem Phys 2013. [DOI: 10.1016/j.chemphys.2012.12.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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49
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Evans CM, Narayanan S, Jiang Z, Torkelson JM. Modulus, confinement, and temperature effects on surface capillary wave dynamics in bilayer polymer films near the glass transition. PHYSICAL REVIEW LETTERS 2012; 109:038302. [PMID: 22861904 DOI: 10.1103/physrevlett.109.038302] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 05/08/2012] [Indexed: 06/01/2023]
Abstract
We report relaxation times (τ) for surface capillary waves on 27-127 nm polystyrene (PS) top layers in bilayer films using x-ray photon correlation spectroscopy. At ∼10 °C above the PS glass transition temperature (T(g)), τ tracks with underlayer modulus, being significantly smaller on softer substrates at low in-plane scattering wave vector. Relative to capillary wave theory, we also report stiffening behavior upon nanoconfinement of the PS layers. At PS T(g)+40 °C, both effects become negligible. We demonstrate how neighboring polymer domains impact dynamics over substantial length scales.
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Affiliation(s)
- Christopher M Evans
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA
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50
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Fukao K, Terasawa T, Oda Y, Nakamura K, Tahara D. Glass transition dynamics of stacked thin polymer films. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:041808. [PMID: 22181166 DOI: 10.1103/physreve.84.041808] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Indexed: 05/31/2023]
Abstract
The glass transition dynamics of stacked thin films of polystyrene and poly(2-chlorostyrene) were investigated using differential scanning calorimetry and dielectric relaxation spectroscopy. The glass transition temperature T(g) of as-stacked thin polystyrene films has a strong depression from that of the bulk samples. However, after annealing at high temperatures above T(g), the stacked thin films exhibit glass transition at a temperature almost equal to the T(g) of the bulk system. The α-process dynamics of stacked thin films of poly(2-chlorostyrene) show a time evolution from single-thin-film-like dynamics to bulk-like dynamics during the isothermal annealing process. The relaxation rate of the α process becomes smaller with increase in the annealing time. The time scale for the evolution of the α dynamics during the annealing process is very long compared with that for the reptation dynamics. At the same time, the temperature dependence of the relaxation time for the α process changes from Arrhenius-like to Vogel-Fulcher-Tammann dependence with increase of the annealing time. The fragility index increases and the distribution of the α-relaxation times becomes smaller with increase in the annealing time for isothermal annealing. The observed change in the α process is discussed with respect to the interfacial interaction between the thin layers of stacked thin polymer films.
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Affiliation(s)
- Koji Fukao
- Department of Physics, Ritsumeikan University, Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan.
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