151
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Klonos PA, Patelis N, Glynos E, Sakellariou G, Kyritsis A. Molecular Dynamics in Polystyrene Single-Chain Nanoparticles. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b02070] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Panagiotis A. Klonos
- Department of Physics, National Technical University of Athens, Zografou Campus, 15780 Athens, Greece
| | - Nikolaos Patelis
- Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografrou, 15771 Athens, Greece
| | - Emmanouil Glynos
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, P.O.
Box 1385, Heraklion, 711 10 Crete, Greece
| | - Georgios Sakellariou
- Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografrou, 15771 Athens, Greece
| | - Apostolos Kyritsis
- Department of Physics, National Technical University of Athens, Zografou Campus, 15780 Athens, Greece
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152
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Zuo B, Xu Q, Jin T, Xing H, Shi J, Hao Z, Zhang L, Tanaka K, Wang X. Suppressed Surface Reorganization in a High-Density Poly(methyl methacrylate) Brush. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:14890-14895. [PMID: 31646872 DOI: 10.1021/acs.langmuir.9b02581] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A high-density poly(methyl methacrylate) (PMMA) brush (σ = 0.77 chain/nm2) with a lower molecular weight distribution was prepared onto a silicon wafer by surface-initiated atom transfer radical polymerization. The surface of the PMMA brush chains was characterized upon the process of the environmental change, from air to water, using contact angle measurements in conjunction with sum-frequency generation spectroscopy. The surface structure and properties altered less with the changing environment from air to water for the PMMA brush than for a spin-coated film; that is, the extent of surface reorganization could be suppressed by grafting densely-packed chains onto a substrate. Also, the water penetration into the brush surface was inhibited because of the densely packed chain structure.
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Affiliation(s)
- Biao Zuo
- Department of Chemistry , Zhejiang Sci-Tech University , 928 Second Avenue, Xiasha Higher Education Zone , Hangzhou 310018 , Zhejiang , China
| | - Quanyin Xu
- Department of Chemistry , Zhejiang Sci-Tech University , 928 Second Avenue, Xiasha Higher Education Zone , Hangzhou 310018 , Zhejiang , China
| | - Tiancheng Jin
- Department of Chemistry , Zhejiang Sci-Tech University , 928 Second Avenue, Xiasha Higher Education Zone , Hangzhou 310018 , Zhejiang , China
| | - Huimin Xing
- Department of Chemistry , Zhejiang Sci-Tech University , 928 Second Avenue, Xiasha Higher Education Zone , Hangzhou 310018 , Zhejiang , China
| | - Jiacheng Shi
- Department of Chemistry , Zhejiang Sci-Tech University , 928 Second Avenue, Xiasha Higher Education Zone , Hangzhou 310018 , Zhejiang , China
| | - Zhiwei Hao
- Department of Chemistry , Zhejiang Sci-Tech University , 928 Second Avenue, Xiasha Higher Education Zone , Hangzhou 310018 , Zhejiang , China
| | - Li Zhang
- Department of Chemistry , Zhejiang Sci-Tech University , 928 Second Avenue, Xiasha Higher Education Zone , Hangzhou 310018 , Zhejiang , China
| | - Keiji Tanaka
- Department of Applied Chemistry , International Institute for Carbon-Neutral Energy Research (WPI-I2CNER) , and Center for Polymer Interface and Molecular Adhesion Science , Kyushu University , 744 Motooka , Nishi-ku, Fukuoka 819-0395 , Fukuoka , Japan
| | - Xinping Wang
- Department of Chemistry , Zhejiang Sci-Tech University , 928 Second Avenue, Xiasha Higher Education Zone , Hangzhou 310018 , Zhejiang , China
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153
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Lukešová M, Švajdlenková H, Reuter D, Valić S, Loidl A, Bartoš J. Spin probe interaction and mobility in confined cyclohexane: Effects of pore size and pore surface composition of silica gel matrices. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.136756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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154
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Kinsey T, Mapesa E, Cosby T, He Y, Hong K, Wang Y, Iacob C, Sangoro J. Elucidating the impact of extreme nanoscale confinement on segmental and chain dynamics of unentangled poly(cis-1,4-isoprene). THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2019; 42:137. [PMID: 31650417 DOI: 10.1140/epje/i2019-11907-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/11/2019] [Indexed: 06/10/2023]
Abstract
Broadband dielectric spectroscopy is employed to probe dynamics in low molecular weight poly(cis-1,4-isoprene) (PI) confined in unidirectional silica nanopores with mean pore diameter, D, of 6.5 nm. Three molecular weights of PI (3, 7 and 10 kg/mol) were chosen such that the ratio of D to the polymer radius of gyration, Rg, is varied from 3.4, 2.3 to 1.9, respectively. It is found that the mean segmental relaxation rate remains bulk-like but an additional process arises at lower frequencies with increasing molecular weight (decreasing D/Rg. In contrast, the mean relaxation rates of the end-to-end dipole vector corresponding to chain dynamics are found to be slightly slower than that in the bulk for the systems approaching D/Rg ∼ 2, but faster than the bulk for the polymer with the largest molecular weight. The analysis of the spectral shapes of the chain relaxation suggests that the resulting dynamics of the 10kg/mol PI confined at length-scales close to that of the Rg are due to non-ideal chain conformations under confinement decreasing the chain relaxation times. The understanding of these faster chain dynamics of polymers under extreme geometrical confinement is necessary in designing nanodevices that contain polymeric materials within substrates approaching the molecular scale.
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Affiliation(s)
- Thomas Kinsey
- Department of Chemical and Biomolecular Engineering, University of Tennessee, 37996, Knoxville, TN, USA
| | - Emmanuel Mapesa
- Department of Chemical and Biomolecular Engineering, University of Tennessee, 37996, Knoxville, TN, USA
| | - Tyler Cosby
- Department of Chemical and Biomolecular Engineering, University of Tennessee, 37996, Knoxville, TN, USA
| | - Youjun He
- Center for Nanophase Materials Science, Oak Ridge National Laboratory, 37831, Oak Ridge, TN, USA
| | - Kunlun Hong
- Center for Nanophase Materials Science, Oak Ridge National Laboratory, 37831, Oak Ridge, TN, USA
| | - Yangyang Wang
- Center for Nanophase Materials Science, Oak Ridge National Laboratory, 37831, Oak Ridge, TN, USA
| | - Ciprian Iacob
- National Research and Development Institute for Cryogenic and Isotopic Technologies, ICSI Rm. Valcea, Rm. Valcea, Romania
- Karlsruhe Institute of Technology (KIT), Institute for Chemical Technology and Polymer Chemistry, 76128, Karlsruhe, Germany
| | - Joshua Sangoro
- Department of Chemical and Biomolecular Engineering, University of Tennessee, 37996, Knoxville, TN, USA.
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155
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Karan K. Interesting Facets of Surface, Interfacial, and Bulk Characteristics of Perfluorinated Ionomer Films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:13489-13520. [PMID: 30753782 DOI: 10.1021/acs.langmuir.8b03721] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Ion-containing perfluorinated polymers possess unique viscoelastic properties, excellent proton conductivity, and nanophase-segregated structure all arising from the clustering of hydrophilic sulfonic acid groups within a matrix of hydrophobic fluorocarbons. When these ionomers are confined to nanothin films, a broad swathe of structural organization imparting a rich variety of surface, interfacial, and bulk characteristics can be expected. However, our understanding of perfluorinated ionomer thin film behavior is still in a rudimentary stage, and much of the research focus to date has been on its hydration-related structure and properties pertinent to electrochemical applications. Thus, many hidden gems-their interesting surface and interfacial properties-have been overlooked. In this Invited Feature Article, which is a summary of the key contributions by the author's group, including several collaborative publications on ionomer thin films, we unravel many of these facets. In addition, the article attempts to integrate knowledge acquired from a variety of investigations of different aspects of the ionomer thin films to refine and develop a consistent picture of their structure and behavior. First, we focus on the self-assembly of ionomers and show that dispersion media and hydrophobicity/hydrophilicity of the substrate can result in partial or even no coverage of substrates, shedding light on the complexity of polymer-substrate, polymer-solvent, and polymer-polymer interactions, an insight completely obscured when the spin-coating method is adopted for film creation. We demonstrate that the same ionomer can be used to create a variety of surfaces ranging from superhydrophilic to highly hydrophobic by controlling the film thickness or through the choice of substrate material. The ultrathin, hydrophilic surfaces of self-assembled Nafion ionomer films exhibit wettability switching behavior which opens the door to creating stimuli-responsive smart surfaces. The thermoresponsive behavior of the films is discussed in the context of surface (wettability) and bulk (thermal expansion) characteristics as well as a newly discovered vibrational mode. The substrate- and film thickness-dependent thermal expansion coefficients reinforce the importance of interfacial interactions and confinement on the structure/properties of these films. They also open up the potential of tuning ionomer bulk properties via substrate chemistry. The discovery of a vibrational mode that becomes thermally activated at high temperature has provided new insights into the origins of the molecular motions responsible for the α-relaxation of the Nafion ionomer as well as the underlying reason for wettability switching. Our recent neutron reflectometry study of different ionomers varying in side-chain composition/length on a platinum substrate shows that the interfacial hydration level is correlated to the side-chain length, which opens up the possibility of the controlling the interfacial electrochemistry. Finally, a systematic analysis of factors affecting proton conduction is presented to elucidate the yet-unresolved origins of the suppressed conduction of nanothin ionomer films compared to that of the bulk membrane. By revealing these interesting yet poorly understood facets of ionomer thin films, the article aims to stimulate further scientific pursuit on this topic.
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Affiliation(s)
- Kunal Karan
- Department of Chemical & Petroleum Engineering , The University of Calgary , Calgary , Alberta T2N1N4 , Canada
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156
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Studying tautomerism in an important pharmaceutical glibenclamide confined in the thin nanometric layers. Colloids Surf B Biointerfaces 2019; 182:110319. [PMID: 31301581 DOI: 10.1016/j.colsurfb.2019.06.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 06/20/2019] [Accepted: 06/21/2019] [Indexed: 11/24/2022]
Abstract
The uniform thin films with variable thicknesses (d = 49, 120, 220 nm) of active pharmaceutical ingredient (API) glibenclamide (GCM) was spin-coated and investigated using broadband dielectric, grazing incident FTIR spectroscopies, atomic force microscopy, and ellipsometry. Data analysis revealed that nanoconfined systems consist of a mixture of amide and imidic acid forms of this pharmaceutical, wherein the ratios of both tautomeric forms in the thin films were different with respect to the molten supercooled bulk system. Moreover, changes in the populations of glibenclamide tautomers, i.e. higher amide to imides ratio in the spatially restricted API with respect to the bulk sample, had a strong impact on the character of the proton transfer reaction. In this context, the kinetic curves constructed on the base of infrared data for the bulk system follow the sigmoidal shape, characteristic for the autocatalytic reaction, while results obtained for the confined samples provide exponential character and indicate first-order transformation. This allows hypothesizing that the autocatalytic nature of the tautomerism in the bulk sample is most likely related to the formation of the amide tautomers which further catalyze the progress of imide-amide transformation. Our results are the first studies showing that the change in the thickness of the film may affect the properties and isomerization kinetics in a pharmaceutical systems. Finally, our data open a new perspective for developing new drug delivery systems.
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157
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Ishioka S, Watanabe K, Imai H, Tseng YJ, Peng CH, Oaki Y. Glass-transition-induced color-changing resins containing layered polydiacetylene. Chem Commun (Camb) 2019; 55:11723-11726. [PMID: 31512688 DOI: 10.1039/c9cc05303d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A phase-segregated composite of polystyrene (PSt) and layered polydiacetylene (PDA) was formed through simultaneous polymerization and crystallization. As the motion of PSt chains with glass transition is transferred to that of PDA, the color change was achieved by the shortening of the conjugation length with deformation of the layered structure.
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Affiliation(s)
- Shuhei Ishioka
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
| | - Kei Watanabe
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
| | - Hiroaki Imai
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
| | - Yu-Jen Tseng
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chi-How Peng
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yuya Oaki
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
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158
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Abstract
We review recent neutron scattering work and related results from simulation and complementary techniques focusing on the microscopic dynamics of polymers under confinement. Confinement is either realized in model porous materials or in polymer nanocomposites (PNC). The dynamics of such confined polymers is affected on the local segmental level, the level of entanglements as well as on global levels: (i) at the segmental level the interaction with the surface is of key importance. At locally repulsive surfaces compared to the bulk the segmental dynamics is not altered. Attractive surfaces slow down the segmental dynamics in their neighborhood but do not give rise to dead, glassy layers. (ii) Confinement generally has little effect on the inter-chain entanglements: both for weakly as well as for marginally confined polymers the reptation tube size is not changed. Only for strongly confined polymers disentanglement takes place. Similarly, in PNC at higher NP loading disentanglement phenomena are observed; in addition, at very high loading a transition from polymer caused topological constraints to purely geometrical constraints is observed. (iii) On the more global scale NSE experiments revealed important information on the nature of the interphase between adsorbed layer and bulk polymer. (iv) Polymer grafts at NP mutually confine each other, an effect that is most pronounced for one component NP. (v) Global diffusion of entangled polymers both in weakly and strongly attractive PNC is governed by the ratio of bottle-neck to chain size that characterizes the 'entropic barrier' for global diffusion.
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Affiliation(s)
- Dieter Richter
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Complex Systems (ICS-1), Forschungszentrum Jülich GmbH, Jülich, Germany.
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159
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Wang Y, Gu K, Monnier X, Jeong H, Chowdhury M, Cangialosi D, Loo YL, Priestley RD. Tunable Properties of MAPLE-Deposited Thin Films in the Presence of Suppressed Segmental Dynamics. ACS Macro Lett 2019; 8:1115-1121. [PMID: 35619457 DOI: 10.1021/acsmacrolett.9b00406] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Processing polymer thin films by physical vapor deposition has been a major challenge due to material degradation. This challenge has limited our understanding of morphological control by top-down approaches that can be crucial for many applications. Recently, matrix-assisted pulsed laser evaporation (MAPLE) has emerged as an alternative route to fabricate polymer thin films from near-gas phase growth conditions. In this Letter, we investigate how this approach can result in a stable two-phase film structure of semicrystalline polymers via a unique combination of MAPLE and flash calorimetry. In the case of MAPLE-deposited poly(ethylene oxide) (PEO) thin films, we find a 35 °C enhancement in the glass transition temperature relative to melt-crystallized films, which is associated with irreversible chain adsorption in the amorphous region of the film. Remarkably, by varying substrate temperature during deposition, we reveal the ability to significantly tune the crystal orientation, extent of crystallinity, and lamellar thickness of MAPLE-deposited PEO thin films.
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Affiliation(s)
- Yucheng Wang
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Kaichen Gu
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Xavier Monnier
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 San Sebastián, Spain
| | - Hyuncheol Jeong
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Mithun Chowdhury
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Metallurgical Engineering and Materials Science, Indian Institute of Technology, Bombay, Mumbai 400076, India
| | - Daniele Cangialosi
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 San Sebastián, Spain
- Centro de Física de Materiales (CSIC-UPV/EHU), Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
| | - Yueh-Lin Loo
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, United States
| | - Rodney D. Priestley
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, United States
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160
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Shi G, Guan Y, Liu G, Müller AJ, Wang D. Segmental Dynamics Govern the Cold Crystallization of Poly(lactic acid) in Nanoporous Alumina. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00542] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Guangyu Shi
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Engineering Plastics, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu Guan
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Engineering Plastics, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guoming Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Engineering Plastics, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Alejandro J. Müller
- POLYMAT and Polymer Science and Technology Department, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel de Lardizabal 3, Donostia-San Sebastián 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Spain
| | - Dujin Wang
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Engineering Plastics, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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161
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Sasaki T, Ito Y, Sasai T, Irie S. Glass transition of a polystyrene surface as detected via two-dimensional diffusion of Au atoms during physical vapor deposition. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.121577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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162
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Chandran S, Baschnagel J, Cangialosi D, Fukao K, Glynos E, Janssen LMC, Müller M, Muthukumar M, Steiner U, Xu J, Napolitano S, Reiter G. Processing Pathways Decide Polymer Properties at the Molecular Level. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01195] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
| | - Jörg Baschnagel
- Institut Charles Sadron, Université de Strasbourg & CNRS, 23 rue du Loess, 67034 Cedex, Strasbourg, France
| | - Daniele Cangialosi
- Centro de Física de Materiales CFM (CSIC-UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 San Sebastin, Spain
| | - Koji Fukao
- Department of Physics, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Emmanouil Glynos
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, P.O.
Box 1385, 711 10 Heraklion, Crete, Greece
| | - Liesbeth M. C. Janssen
- Theory of Polymers and Soft Matter, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, The Netherlands
| | - Marcus Müller
- Institute for Theoretical Physics, Georg-August-Universität, Göttingen, Germany
| | - Murugappan Muthukumar
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Ullrich Steiner
- Adolphe Merkle Institute, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
| | - Jun Xu
- Advanced Materials Laboratory of Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Simone Napolitano
- Laboratory of Polymer and Soft Matter Dynamics, Experimental Soft Matter and Thermal Physics, Faculté des Sciences, Université libre de Bruxelles (ULB), CP223, Boulevard du Triomphe, Bruxelles 1050, Belgium
| | - Günter Reiter
- Institute of Physics, University of Freiburg, Freiburg 79104, Germany
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163
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Debot A, Tripathi P, Napolitano S. Solution filtering affects the glassy dynamics of spincoated thin films of poly(4-chlorostyrene). THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2019; 42:102. [PMID: 31396728 DOI: 10.1140/epje/i2019-11865-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/16/2019] [Indexed: 06/10/2023]
Abstract
We investigated the impact of sample preparation on the glassy dynamics of thin films of poly(4-chlorostyrene), a polymer whose molecular mobility is particularly sensitive to changes in the specific volume. Samples were obtained by spincoating, the technique most commonly used to prepare thin organic layers, which consists of pouring dilute polymer solutions onto a plate rotating at a high rate. Our experimental results demonstrate that filtering the solutions before spincoating affects the value of the segmental relaxation time of the as-prepared films. Thin polymer layers obtained via filtered solutions show accelerated segmental dynamics upon confinement at the nanoscale level, once below 100nm, while the samples obtained via unfiltered solutions exhibit bulk-like dynamics down to 15-20nm. We analyzed these results by means of the cooperative free volume rate model, considering a larger free volume content in thin films obtained via filtered solutions. The validity of the model predictions was finally verified by measurements of irreversible adsorption, confirming a larger adsorbed amount, corresponding to a higher specific volume, in the case of samples obtained via unfiltered solutions. Our results prove that filtering is a crucial step in the preparation of thin films, and it could be used to switch on and off nanoconfinement effects.
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Affiliation(s)
- Alice Debot
- Polymer and Soft Matter Dynamics, Experimental Soft Matter and Thermal Physics (EST), Faculté des Sciences, Université libre de Bruxelles (ULB), Brussels, Belgium
| | - Pragya Tripathi
- Polymer and Soft Matter Dynamics, Experimental Soft Matter and Thermal Physics (EST), Faculté des Sciences, Université libre de Bruxelles (ULB), Brussels, Belgium
| | - Simone Napolitano
- Polymer and Soft Matter Dynamics, Experimental Soft Matter and Thermal Physics (EST), Faculté des Sciences, Université libre de Bruxelles (ULB), Brussels, Belgium.
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164
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Kang E, Graczykowski B, Jonas U, Christie D, Gray LAG, Cangialosi D, Priestley RD, Fytas G. Shell Architecture Strongly Influences the Glass Transition, Surface Mobility, and Elasticity of Polymer Core-Shell Nanoparticles. Macromolecules 2019; 52:5399-5406. [PMID: 31367064 PMCID: PMC6659035 DOI: 10.1021/acs.macromol.9b00766] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/14/2019] [Indexed: 01/29/2023]
Abstract
Despite the growing application of nanostructured polymeric materials, there still remains a large gap in our understanding of polymer mechanics and thermal stability under confinement and near polymer-polymer interfaces. In particular, the knowledge of polymer nanoparticle thermal stability and mechanics is of great importance for their application in drug delivery, phononics, and photonics. Here, we quantified the effects of a polymer shell layer on the modulus and glass-transition temperature (T g) of polymer core-shell nanoparticles via Brillouin light spectroscopy and modulated differential scanning calorimetry, respectively. Nanoparticles consisting of a polystyrene (PS) core and shell layers of poly(n-butyl methacrylate) (PBMA) were characterized as model systems. We found that the high T g of the PS core was largely unaffected by the presence of an outer polymer shell, whereas the lower T g of the PBMA shell layer decreased with increasing PBMA thickness. The surface mobility was revealed at a temperature about 15 K lower than the T g of the PBMA shell layer. Overall, the modulus of the core-shell nanoparticles decreased with increasing PBMA shell layer thickness. These results suggest that the nanoparticle modulus and T g can be tuned independently through the control of nanoparticle composition and architecture.
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Affiliation(s)
- Eunsoo Kang
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Bartlomiej Graczykowski
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Faculty
of Physics, Adam Mickiewicz University, Umultowska 85, 61614 Poznan, Poland
| | - Ulrich Jonas
- Department
of Chemistry and Biology, University of
Siegen, Adolf-Reichwein-Strasse 2, 57076 Siegen, Germany
| | - Dane Christie
- Department
of Chemical and Biological Engineering and Princeton Institute for the Science
and Technology of Materials, Princeton University, Princeton, New Jersey 08544, United States
| | - Laura A. G. Gray
- Department
of Chemical and Biological Engineering and Princeton Institute for the Science
and Technology of Materials, Princeton University, Princeton, New Jersey 08544, United States
| | - Daniele Cangialosi
- Centro
de
Física de Materiales (CSIC-UPV/EHU), Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
- Donostia
International Physics Center, Paseo Manuel de Lardizabal 4, 20018 San Sebastián, Spain
| | - Rodney D. Priestley
- Department
of Chemical and Biological Engineering and Princeton Institute for the Science
and Technology of Materials, Princeton University, Princeton, New Jersey 08544, United States
| | - George Fytas
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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165
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Li SJ, Qian HJ, Lu ZY. A comparative study on the dynamic heterogeneity of supercooled polymers under nanoconfinement. Phys Chem Chem Phys 2019; 21:15888-15898. [PMID: 31287116 DOI: 10.1039/c9cp02550b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Dynamic heterogeneity (DH) is a universal property of glass transition phenomena. In this work, we perform a comparative analysis of DH for pure polymer and polymer/nanoparticle composite systems in both film and bulk states via molecular dynamics simulations. We find that the dynamic gradient and the faster average dynamics due to the presence of a free surface are two leading factors, resulting from a nanoconfinement effect, which influence different parts of DH in a film system. The dynamic gradient results from differences in dynamics at different distances from the mobile surface, which induces a large deviation from the Gaussian distribution for the displacement distribution in the film. At the same time, the maximum string size which describes the region size for cooperative motion (dynamic correlation) can also be influenced by the dynamic gradient, although this influence is much weaker than that on the displacement distribution. On the other hand, reflecting temporal fluctuations of dynamics or temporal parts of DH, characteristic peak times of the non-Gaussian parameter and string size, and the ratio between persistent times and exchange times which describe the dynamic exchange properties, are mainly influenced by the faster dynamics on average. Our results demonstrate that measuring different properties (dynamic distribution, dynamic correlation or dynamic exchange) place an emphasis on distinct temporal and spatial parts of DH. It is necessary to use combinational measurements of these properties to give a complete picture of DH in nanoconfinement environments.
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Affiliation(s)
- Shu-Jia Li
- State Key Laboratory of Supramolecular Structure and Materials, International Joint Research Laboratory of Nano-Micro Architecture Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130021, China.
| | - Hu-Jun Qian
- State Key Laboratory of Supramolecular Structure and Materials, International Joint Research Laboratory of Nano-Micro Architecture Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130021, China.
| | - Zhong-Yuan Lu
- State Key Laboratory of Supramolecular Structure and Materials, International Joint Research Laboratory of Nano-Micro Architecture Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130021, China.
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166
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Zhang W, Starr FW, Douglas JF. Collective Motion in the Interfacial and Interior Regions of Supported Polymer Films and Its Relation to Relaxation. J Phys Chem B 2019; 123:5935-5941. [PMID: 31192601 PMCID: PMC7430234 DOI: 10.1021/acs.jpcb.9b04155] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To understand the role of collective motion in the often large changes in interfacial molecular mobility observed in polymer films, we investigate the extent of collective motion in the interfacial regions of a thin supported polymer film and within the film interior by molecular dynamics simulation. Contrary to commonly stated expectations, we find that the extent of collective motion, as quantified by string-like molecular exchange motion, is similar in magnitude in the polymer-air interfacial layer as the film interior and distinct from the bulk material. This finding is consistent with Adam-Gibbs description of the segmental dynamics within mesoscopic film regions, where the extent of collective motion is related to the configurational entropy of the film as a whole rather than a locally defined extent of collective motion or configurational entropy.
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Affiliation(s)
- Wengang Zhang
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459-0155, United States
| | - Francis W. Starr
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459-0155, United States
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
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167
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Phan AD, Schweizer KS. Influence of Longer Range Transfer of Vapor Interface Modified Caging Constraints on the Spatially Heterogeneous Dynamics of Glass-Forming Liquids. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00754] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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168
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Chandran S, Reiter G. Segmental Rearrangements Relax Stresses in Nonequilibrated Polymer Films. ACS Macro Lett 2019; 8:646-650. [PMID: 35619518 DOI: 10.1021/acsmacrolett.9b00116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We probed the relaxation of preparation-induced residual stresses in nonequilibrated polymer films through dewetting experiments. While we observed fast relaxations at temperatures close to or below the glass transition, at elevated temperatures these relaxation times were orders of magnitude longer than the reptation time. Intriguingly, applying appropriate scaling of preparation conditions allowed us to present all relaxation times, including published data, from various complementary experiments on a single master curve exhibiting an Arrhenius-type behavior. The corresponding activation energy (75 ± 10 kJ/mol) is similar to values obtained for the relaxation of segments in polystyrene. The observed long relaxation times suggest that residual stresses, a consequence of nonequilibrium conformations inherited from preparation, relax via concerted rearrangements of many segments.
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Affiliation(s)
- Sivasurender Chandran
- Institute of Physics, University of Freiburg, Herman Herder Str. 3, Freiburg, 79104, Germany
| | - Günter Reiter
- Institute of Physics, University of Freiburg, Herman Herder Str. 3, Freiburg, 79104, Germany
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169
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Muanchan P, Kurose T, Ito H. Replication of Mesoscale Pore One-dimensional Nanostructures: Surface-induced Phase Separation of Polystyrene/Poly(vinyl alcohol) (PS/PVA) Blends. Polymers (Basel) 2019; 11:E1039. [PMID: 31212801 PMCID: PMC6630784 DOI: 10.3390/polym11061039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 06/03/2019] [Accepted: 06/07/2019] [Indexed: 01/18/2023] Open
Abstract
Mesoscale pore one-dimensional (1D) nanostructures, or vertically aligned porous nanostructures (VAPNs), have attracted attention with their excellent hydrophobic properties, ultra-high surface area, and high friction coefficient, compared to conventional vertically aligned nanostructures (VANs). In this study, we investigate the replication of VAPNs produced by the thermal nanoimprint process using anodic aluminum oxide (AAO2) templates (100 nm diameter). Polystyrene/poly(vinyl alcohol) (PS1/PVA) blends, prepared by the advanced melt-mixing process with an ultra-high shear rate, are used to investigate the formation of porosity at the nanometer scale. The results reveal that domain size and mass ratios of PVA precursors in the PS matrix play a dominant role in the interfacial interaction behavior between PS1-PVA-AAO2, on the obtained morphologies of the imprinted nanostructures. With a PVA nanodomain precursor (PS1/PVA 90/10 wt%), the integration of PVA nanodroplets on the AAO2 wall due to the hydrogen bonding that induces the phase separation between PS1-PVA results in the formation of VAPNs after removal of the PVA segment. However, in the case of PVA microdomain precursors (PS1/PVA 70/30 wt%), the structure transformation behavior of PS1 is induced by the Rayleigh instability between PVA encapsulated around the PS1 surfaces, resulting in the PS1 nanocolumns transforming into nanopeapods composed of nanorods and nanospheres.
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Affiliation(s)
- Paritat Muanchan
- Graduate School of Organic Materials Science, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan.
| | - Takashi Kurose
- Research Center for GREEN Materials and Advanced Processing (GMAP), Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan.
| | - Hiroshi Ito
- Graduate School of Organic Materials Science, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan.
- Research Center for GREEN Materials and Advanced Processing (GMAP), Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan.
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170
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Giunta G, Carbone P. Cross-over in the dynamics of polymer confined between two liquids of different viscosity. Interface Focus 2019; 9:20180074. [PMID: 31065342 PMCID: PMC6501349 DOI: 10.1098/rsfs.2018.0074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2019] [Indexed: 11/12/2022] Open
Abstract
Using molecular dynamics simulations, we analysed the polymer dynamics of chains of different molecular weights entrapped at the interface between two immiscible liquids. We showed that on increasing the viscosity of one of the two liquids the dynamic behaviour of the chain changes from a Zimm-like dynamics typical of dilute polymer solutions to a Rouse-like dynamics where hydrodynamic interactions are screened. We observed that when the polymer is in contact with a high viscosity liquid, the number of solvent molecules close to the polymer beads is reduced and ascribed the screening effect to this reduced number of polymer-solvent contacts. For the longest chain simulated, we calculated the distribution of loop length and compared the results with the theoretical distribution developed for solid/liquid interfaces. We showed that the polymer tends to form loops (although flat against the interface) and that the theory works reasonably well also for liquid/liquid interfaces.
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Affiliation(s)
- Giuliana Giunta
- School of Chemical Engineering and Analytical Science, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Paola Carbone
- School of Chemical Engineering and Analytical Science, University of Manchester, Oxford Road, Manchester M13 9PL, UK
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171
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Li SJ, Qian HJ, Lu ZY. A simulation study on the glass transition behavior and relevant segmental dynamics in free-standing polymer nanocomposite films. SOFT MATTER 2019; 15:4476-4485. [PMID: 31111851 DOI: 10.1039/c9sm00267g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In polymer/nanoparticle composite (PNC) thin films, polymer chains experience strong confinement effects not only at the free surface area but also from nanoparticles (NPs). In this work, the influence of NP-polymer interaction and NP distribution on the polymer segmental dynamics and the glass transition behavior of PNC free-standing films are investigated through molecular dynamics simulations. We demonstrate that NPs will migrate to the film surface area and form an NP-concentrated layer when NP-polymer interactions are weak, while NPs are well dispersed in the bulk region when NP-polymer interactions are strong. In both cases, we find increases in the glass transition temperature Tg compared with the pure film without NPs, although with a different degree. The weakly interacting system has the same Tg as the pure bulk system without NPs. The NP layer formed at the surface area reduces both the mobility of the surface polymer beads and the mobility gradient in the film normal direction (MGFND), therefore resulting in an increase in the Tg which highlights the vital role of the mobile surface layer. In contrast, the NPs in the bulk region enlarge the MGFND. NPs have opposite influences on the polymer bead dynamic anisotropy when they interact weakly or strongly with polymers, weakened for the former and enhanced for the latter. These findings offer a clear picture of the segmental dynamics and glass transition behavior in free-standing PNC films with different NP-polymer interaction strengths. We hope these results will be helpful for the property design of related materials.
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Affiliation(s)
- Shu-Jia Li
- State Key Laboratory of Supramolecular Structure and Materials, International Joint Research Laboratory of Nano-Micro Architecture Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130021, China.
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172
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Xu J, Wu HC, Zhu C, Ehrlich A, Shaw L, Nikolka M, Wang S, Molina-Lopez F, Gu X, Luo S, Zhou D, Kim YH, Wang GJN, Gu K, Feig VR, Chen S, Kim Y, Katsumata T, Zheng YQ, Yan H, Chung JW, Lopez J, Murmann B, Bao Z. Multi-scale ordering in highly stretchable polymer semiconducting films. NATURE MATERIALS 2019; 18:594-601. [PMID: 30988452 DOI: 10.1038/s41563-019-0340-5] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Accepted: 03/12/2019] [Indexed: 06/09/2023]
Abstract
Stretchable semiconducting polymers have been developed as a key component to enable skin-like wearable electronics, but their electrical performance must be improved to enable more advanced functionalities. Here, we report a solution processing approach that can achieve multi-scale ordering and alignment of conjugated polymers in stretchable semiconductors to substantially improve their charge carrier mobility. Using solution shearing with a patterned microtrench coating blade, macroscale alignment of conjugated-polymer nanostructures was achieved along the charge transport direction. In conjunction, the nanoscale spatial confinement aligns chain conformation and promotes short-range π-π ordering, substantially reducing the energetic barrier for charge carrier transport. As a result, the mobilities of stretchable conjugated-polymer films have been enhanced up to threefold and maintained under a strain up to 100%. This method may also serve as the basis for large-area manufacturing of stretchable semiconducting films, as demonstrated by the roll-to-roll coating of metre-scale films.
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Affiliation(s)
- Jie Xu
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
- Nanoscience and Technology Division, Argonne National Laboratory, Lemont, IL, USA
| | - Hung-Chin Wu
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Chenxin Zhu
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Anatol Ehrlich
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Leo Shaw
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Mark Nikolka
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Sihong Wang
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
- Institute for Molecular Engineering, University of Chicago, Chicago, IL, USA
| | - Francisco Molina-Lopez
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
- Department of Materials Engineering, KU Leuven, Belgium
| | - Xiaodan Gu
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- School of Polymer Science and Engineering, University of Southern Mississippi, Hattiesburg, MS, USA
| | - Shaochuan Luo
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing, China
| | - Dongshan Zhou
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing, China
| | - Yun-Hi Kim
- Department of Chemistry and RINS, Gyeongsang National University, Jinju, South Korea
| | | | - Kevin Gu
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Vivian Rachel Feig
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Shucheng Chen
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Yeongin Kim
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Toru Katsumata
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
- Corporate Research and Development, Performance Materials Technology Center, Asahi Kasei Corporation, Fuji, Shizuoka, Japan
| | - Yu-Qing Zheng
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - He Yan
- Department of Chemistry and Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Jong Won Chung
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
- Material Research Center, Samsung Advanced Institute of Technology Yeongtong-gu, Suwon-si, Gyeonggi-do, South Korea
| | - Jeffrey Lopez
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Boris Murmann
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Zhenan Bao
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA.
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173
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Politidis C, Alexandris S, Sakellariou G, Steinhart M, Floudas G. Dynamics of Entangled cis-1,4-Polyisoprene Confined to Nanoporous Alumina. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00523] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
| | | | - Georgios Sakellariou
- Department of Chemistry, National and Kapodistrian University of Athens, 15771 Athens, Greece
| | - Martin Steinhart
- Institut für Chemie neuer Materialien, Universität Osnabrück, D-49069 Osnabrück, Germany
| | - George Floudas
- Department of Physics, University of Ioannina, 45110 Ioannina, Greece
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174
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Zuo B, Zhou H, Davis MJB, Wang X, Priestley RD. Effect of Local Chain Conformation in Adsorbed Nanolayers on Confined Polymer Molecular Mobility. PHYSICAL REVIEW LETTERS 2019; 122:217801. [PMID: 31283350 DOI: 10.1103/physrevlett.122.217801] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Indexed: 05/26/2023]
Abstract
Interfaces play an important role in modifying the dynamics of polymers confined to the nanoscale. We demonstrate that the distance over which an interface suppresses molecular mobility in poly(styrene) thin films can be systematically increased by tens of nanometers by controlling the chain of conformation, i.e., the height of the loops in irreversibly adsorbed nanolayers. These effects arise from topological interaction between adsorbed and neighboring unadsorbed chains, respectively, which increase their motional coupling to facilitate the propagation of suppressed dynamics originating at the interface, thus highlighting the ability to manipulate interfacial effects by local conformation of chains in adsorbed nanolayers.
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Affiliation(s)
- Biao Zuo
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Hao Zhou
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Mary J B Davis
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Xinping Wang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Rodney D Priestley
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
- Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, USA
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175
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Peng YJ, Cai CT, Wang CJ, Zuo ZF, Liu XZ. Probing the glass transition in reversible cross-linked polymer composites. RSC Adv 2019; 9:15318-15322. [PMID: 35514860 PMCID: PMC9064213 DOI: 10.1039/c9ra01942a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 04/11/2019] [Indexed: 11/21/2022] Open
Abstract
Understanding the nature of glass transition is still a great challenge. Glass transition is widely observed in many glassy materials; however, it has never been unambiguously observed in reversible cross-linked polymer, which is an ideal model of the percolation process. Herein, we report the synthesis of a reversible cross-linked polymer incorporated with four-armed Diels-Alder (DA) dynamic covalent bonds, and the robust experimental observation of percolation-induced glass transition in this reversible four-armed cross-linked polymer (DAMF1). Temperature-modulated differential scanning calorimetry (TMDSC) experiment results clearly revealed the presence of a glass transition along with an endothermic or exothermic peak associated with DA/retro-DA (RDA) reaction related to the reconstitution/disassociation of the DAMF1's four-armed cross-linked network. In situ 13C variable-temperature solid-state NMR experiments further confirmed the DA/RDA reaction during glass transition at a molecular level. The above experimental results provide a direct experimental evidence for the recently developed percolation model of glass transition, which provides new insights into the nature of glass transition.
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Affiliation(s)
- Yong-Jin Peng
- College of Comprehensive Studies, Jinzhou Medical University Jinzhou 121001 P. R. China
- College of Chemistry, Nankai University Tianjin 300071 P. R. China
- Liaoning Key Laboratory of Diabetic Cognitive and Perceptive Dysfunction, Jinzhou Medical University Jinzhou 121001 P. R. China
| | - Chen-Ting Cai
- College of Chemistry, Nankai University Tianjin 300071 P. R. China
| | - Chang-Jun Wang
- College of Comprehensive Studies, Jinzhou Medical University Jinzhou 121001 P. R. China
| | - Zhong-Fu Zuo
- Department of Anatomy, Histology and Embryology, Jinzhou Medical University Jinzhou 121001 P. R. China
- Department of Anatomy, Histology and Embryology, Postdoctoral Research Station, Guangxi Medical University Nanning 530021 P. R. China
- Liaoning Key Laboratory of Diabetic Cognitive and Perceptive Dysfunction, Jinzhou Medical University Jinzhou 121001 P. R. China
| | - Xue-Zheng Liu
- Department of Anatomy, Histology and Embryology, Jinzhou Medical University Jinzhou 121001 P. R. China
- Liaoning Key Laboratory of Diabetic Cognitive and Perceptive Dysfunction, Jinzhou Medical University Jinzhou 121001 P. R. China
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176
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Zuo B, Wang F, Hao Z, He H, Zhang S, Priestley RD, Wang X. Influence of the Interfacial Effect on Polymer Thin-Film Dynamics Scaled by the Distance of Chain Mobility Suppression by the Substrate. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00226] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Biao Zuo
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Fengliang Wang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Zhiwei Hao
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Haolin He
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Shasha Zhang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Rodney D. Priestley
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Xinping Wang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
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177
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Sasaki T, Nakane T, Sato A. Segmental dynamics of free-standing and supported polymer thin films predicted from a surface-controlled model. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.04.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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178
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Samanta S, Huang G, Gao G, Zhang Y, Zhang A, Wolf S, Woods CN, Jin Y, Walsh PJ, Fakhraai Z. Exploring the Importance of Surface Diffusion in Stability of Vapor-Deposited Organic Glasses. J Phys Chem B 2019; 123:4108-4117. [PMID: 30998844 DOI: 10.1021/acs.jpcb.9b01012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Stable glasses are formed during physical vapor deposition (PVD), through the surface-mediated equilibration process. Understanding surface relaxation dynamics is important in understanding the details of this process. Direct measurements of the surface relaxation times in molecular glass systems are challenging. As such, surface diffusion measurements have been used in the past as a proxy for the surface relaxation process. In this study, we show that the absence of enhanced surface diffusion is not a reliable predictor of reduced ability to produce stable glasses. To demonstrate, we have prepared stable glasses (SGs) from two structurally similar organic molecules, 1,3-bis(1-naphthyl)-5-(2-naphthyl)benzene (TNB) and 9-(3,5-di(naphthalen-1-yl)phenyl)anthracene (α,α-A), with similar density increase and improved kinetic stability as compared to their liquid-quenched (LQ) counterparts. The surface diffusion values of these glasses were measured both in the LQ and SG states below their glass transition temperatures ( Tgs) using gold nanorod probes. While TNB shows enhanced surface diffusion in both SG and LQ states, no significant surface Tg diffusion is observed on the surface of α,α-A within our experimental time scales. However, isothermal dewetting experiments on ultrathin films of both molecules below Tg indicate the existence of enhanced dynamics in ultrathin films for both molecules, indirectly showing the existence of an enhanced mobile surface layer. Both films produce stable glasses, which is another indication for the existence of the mobile surface layer. Our results suggest that lateral surface diffusion may not be a good proxy for enhanced surface relaxation dynamics required to produce stable glasses, and thus, other types of measurements to directly probe the surface relaxation times may be necessary.
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Affiliation(s)
- Subarna Samanta
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Georgia Huang
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Gui Gao
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Yue Zhang
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Aixi Zhang
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Sarah Wolf
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Connor N Woods
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Yi Jin
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Patrick J Walsh
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Zahra Fakhraai
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
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179
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A ND, Begam N, Ibrahim M, Chandran S, Padmanabhan V, Sprung M, Basu JK. Viscosity and fragility of confined polymer nanocomposites: a tale of two interfaces. NANOSCALE 2019; 11:8546-8553. [PMID: 30990482 DOI: 10.1039/c8nr10362c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Viscosity and fragility are key parameters determining the processability and thermo-mechanical stability of glassy polymers and polymer nanocomposites (PNCs). In confined polymers, these parameters are largely dominated by the long relaxation times of the polymers adsorbed at the substrate-polymer interface. On the other hand, for polymer nanocomposites, the interface layer (IL) between the nanoparticles and the surrounding matrix chains often control not only the morphology and dispersion but also various parameters like viscosity and glass transition temperature. Confined PNCs, hence, present a unique opportunity to study the interplay of these two independent interfacial effects. Here, we report the results of X-ray scattering based dynamics measurements of PNC thin films, with a two IL width, unraveling the subtle interplay of these two interfaces on the measured viscosity and fragility. Coupled with coarse-grained molecular dynamics (MD) simulations, our experimental results demonstrate that the viscosity of the PNC films increases with both the IL width and the thickness of the polymer layer adsorbed at the substrate interface. However, while both pristine PS and PNCs with a higher IL width become stronger glasses, as estimated by their fragility, the PNC with a lower IL width shows an increase in fragility with increasing confinement. Our results suggest a novel method to control thermo-mechanical properties and stability of PNC coatings by independently controlling the two interfacial effects in athermal glassy PNCs.
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Affiliation(s)
- Nimmi Das A
- Department of Physics, Indian Institute of Science, Bangalore, 560012, India.
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180
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Qian Z, Cao Z, Galuska L, Zhang S, Xu J, Gu X. Glass Transition Phenomenon for Conjugated Polymers. MACROMOL CHEM PHYS 2019. [DOI: 10.1002/macp.201900062] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Zhiyuan Qian
- School of Polymer Science and Engineering Center for Optoelectronic Materials and Device The University of Southern Mississippi Hattiesburg MS 39406 USA
| | - Zhiqiang Cao
- School of Polymer Science and Engineering Center for Optoelectronic Materials and Device The University of Southern Mississippi Hattiesburg MS 39406 USA
| | - Luke Galuska
- School of Polymer Science and Engineering Center for Optoelectronic Materials and Device The University of Southern Mississippi Hattiesburg MS 39406 USA
| | - Song Zhang
- School of Polymer Science and Engineering Center for Optoelectronic Materials and Device The University of Southern Mississippi Hattiesburg MS 39406 USA
| | - Jie Xu
- Argonne National Laboratory Lemont IL 60439 USA
| | - Xiaodan Gu
- School of Polymer Science and Engineering Center for Optoelectronic Materials and Device The University of Southern Mississippi Hattiesburg MS 39406 USA
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181
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Chang T, Zhang H, Shen X, Hu Z. Polymer-Polymer Interfacial Perturbation on the Glass Transition of Supported Low Molecular Weight Polystyrene Thin Films. ACS Macro Lett 2019; 8:435-441. [PMID: 35651128 DOI: 10.1021/acsmacrolett.9b00118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Clarifying interfacial perturbation on polymer relaxation is important for polymer material development. Herein we investigated polymer-polymer interfacial perturbation on low molecular weight (MW) polystyrene (PS) thin film (15-180 nm) glass transition by depositing various polymers atop PS films. Overall, rubbery topcoats induced Tg depression of PS thin film (below 60 nm), while glassy topcoats induced Tg elevation of PS thin film (below 30 nm). Importantly, for the rubbery topcoat, Tg perturbation strength is largely dependent on the Tg difference between interfacial polymers and a larger Tg difference would induce stronger perturbation, while for the glassy topcoat this dependence is inconspicuous. Meanwhile, the interfacial perturbation length during PS glass transition by rubbery topcoats is estimated to be around 8 nm, while it is considered to be about 3.5 nm for glassy topcoats. The different interfacial perturbation length induced by disparate topcoats was accounted for by their different perturbation strength on adjacent PS molecules and disparate interfacial roughness. The results can promote the understanding of polymer interfacial perturbation and benefit the design and development of polymer-based materials.
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Affiliation(s)
- Tongxin Chang
- School of Optoelectronic Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China
- Soft Condensed Matter Physics and Interdisciplinary Research Center, Soochow University, Suzhou 215006, China
- Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006, China
| | - Hui Zhang
- School of Optoelectronic Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China
- Soft Condensed Matter Physics and Interdisciplinary Research Center, Soochow University, Suzhou 215006, China
- Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006, China
| | - Xuezhen Shen
- School of Optoelectronic Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China
- Soft Condensed Matter Physics and Interdisciplinary Research Center, Soochow University, Suzhou 215006, China
- Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006, China
| | - Zhijun Hu
- School of Optoelectronic Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China
- Soft Condensed Matter Physics and Interdisciplinary Research Center, Soochow University, Suzhou 215006, China
- Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006, China
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182
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Nikitin D, Madkour S, Pleskunov P, Tafiichuk R, Shelemin A, Hanuš J, Gordeev I, Sysolyatina E, Lavrikova A, Ermolaeva S, Titov V, Schönhals A, Choukourov A. Cu nanoparticles constrain segmental dynamics of cross-linked polyethers: a trade-off between non-fouling and antibacterial properties. SOFT MATTER 2019; 15:2884-2896. [PMID: 30849134 DOI: 10.1039/c8sm02413h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Copper has a strong bactericidal effect against multi-drug resistant pathogens and polyethers are known for their resistance to biofilm formation. Herein, we combined Cu nanoparticles (NPs) and a polyether plasma polymer in the form of nanocomposite thin films and studied whether both effects can be coupled. Cu NPs were produced by magnetron sputtering via the aggregation in a cool buffer gas whereas polyether layers were synthesized by Plasma-Assisted Vapor Phase Deposition with poly(ethylene oxide) (PEO) used as a precursor. In situ specific heat spectroscopy and XPS analysis revealed the formation of a modified polymer layer around the NPs which propagates on the scale of a few nanometers from the Cu NP/polymer interface and then transforms into a bulk polymer phase. The chemical composition of the modified layer is found to be ether-deficient due to the catalytic influence of copper whereas the bulk polymer phase exhibits the chemical composition close to the original PEO. Two cooperative glass transition phenomena are revealed that belong to the modified polymer layer and the bulk phase. The former is characterized by constrained mobility of polymer segments which manifests itself via a 30 K increase of dynamic glass transition temperature. Furthermore, the modified layer is characterized by the heterogeneous structure which results in higher fragility of this layer as compared to the bulk phase. The Cu NPs/polyether thin films exhibit reduced protein adsorption; however, the constrained segmental dynamics leads to the deterioration of the non-fouling properties for ultra-thin polyether coatings. The films are found to have a bactericidal effect against multi-drug resistant Gram-positive Methicillin-Resistant Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa.
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Affiliation(s)
- Daniil Nikitin
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, Prague, Czech Republic.
| | - Sherif Madkour
- Bundesanstalt für Materialforschung und - prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany.
| | - Pavel Pleskunov
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, Prague, Czech Republic.
| | - Renata Tafiichuk
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, Prague, Czech Republic.
| | - Artem Shelemin
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, Prague, Czech Republic.
| | - Jan Hanuš
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, Prague, Czech Republic.
| | - Ivan Gordeev
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 16200 Prague, Czech Republic
| | - Elena Sysolyatina
- Gamaleya National Research Center of Epidemiology and Microbiology, Gamaleya 18, 123098 Moscow, Russia
| | - Alexandra Lavrikova
- Gamaleya National Research Center of Epidemiology and Microbiology, Gamaleya 18, 123098 Moscow, Russia
| | - Svetlana Ermolaeva
- Gamaleya National Research Center of Epidemiology and Microbiology, Gamaleya 18, 123098 Moscow, Russia
| | - Valerii Titov
- G. A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Akademicheskaya 1, 153045 Ivanovo, Russia
| | - Andreas Schönhals
- Bundesanstalt für Materialforschung und - prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany.
| | - Andrei Choukourov
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, Prague, Czech Republic.
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183
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Adrjanowicz K, Winkler R, Dzienia A, Paluch M, Napolitano S. Connecting 1D and 2D Confined Polymer Dynamics to Its Bulk Behavior via Density Scaling. ACS Macro Lett 2019; 8:304-309. [PMID: 35650833 DOI: 10.1021/acsmacrolett.8b01006] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Under confinement, the properties of polymers can be much different from the bulk. Because of the potential applications in technology and hope to reveal fundamental problems related to the glass-transition, it is important to realize whether the nanoscale and macroscopic behavior of polymer glass-formers are related to each other in any simple way. In this work, we have addressed this issue by studying the segmental dynamics of poly(4-chlorostyrene) (P4ClS) in the bulk and upon geometrical confinement at the nanoscale level, in either one- (thin films on Al substrate) or two- (within alumina nanopores) dimensions. The results demonstrate that the segmental relaxation time, irrespective of the confinement size or its dimensionality, can be scaled onto a single curve when plotted versus ργ/T with the same single scaling exponent, γ = 3.1, obtained via measurements at high pressures in bulk. The implication is that the macro- and nanoscale confined polymer dynamics are intrinsically connected and governed by the same underlying rules.
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Affiliation(s)
- Karolina Adrjanowicz
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Roksana Winkler
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Andrzej Dzienia
- Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
- Institute of Chemistry, University of Silesia, Szkolna 9 1, 40-007 Katowice, Poland
| | - Marian Paluch
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Simone Napolitano
- Laboratory of Polymer and Soft Matter Dynamics, Faculté des Sciences, Université libre de Bruxelles (ULB), CP 223, Boulevard du Triomphe, B-1050 Bruxelles, Belgium
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184
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Lappala A, Sefton L, Fenimore PW, Terentjev EM. Connectivity and free-surface effects in polymer glasses. Sci Rep 2019; 9:3830. [PMID: 30846731 PMCID: PMC6405857 DOI: 10.1038/s41598-019-40286-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 02/08/2019] [Indexed: 11/09/2022] Open
Abstract
The glass transition is one of the few unsolved problems in condensed matter physics: agreement on the cause of the slowing down of structural relaxation in glass-forming liquids is lacking. Glasses are amorphous solids, which do not possess the long-range crystalline order, yet display arrested dynamics and the shear elastic modulus characteristic of equilibrium elasticity. It has been suggested that due to the influence of intramolecular interactions and chain connectivity, the nature of the glass transition in polymers and in standard glass-formers is fundamentally different. Here, we discuss the role of connectivity in polymer glasses, demonstrating that although covalent bonding promotes glass formation, bonding sequentiality that defines a polymer chain is not critical in the bulk: glassy dynamics is purely a result of the number of connections per particle, independently of how these connections are formed, agreeing with the classical Phillips-Thorpe topological constraint theory. We show that bonding sequentiality does play an important role in the surface effects of the glass, highlighting a major difference between polymeric and colloidal glasses. Further, we identify the heterogenous dynamics of model coarse-grained polymer chains both in 'bulk' and near the free surface, and demonstrate characteristic domain patterns in local displacement and connectivity.
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Affiliation(s)
- Anna Lappala
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico, USA. .,Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, USA.
| | - Luke Sefton
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico, USA.,Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Paul W Fenimore
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Eugene M Terentjev
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
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185
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Kipnusu WK, Elmahdy MM, Elsayed M, Krause-Rehberg R, Kremer F. Counterbalance between Surface and Confinement Effects As Studied for Amino-Terminated Poly(propylene glycol) Constraint in Silica Nanopores. Macromolecules 2019. [DOI: 10.1021/acs.macromol.8b02687] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Wycliffe K. Kipnusu
- GROC.UJI, Institute of New Imaging Technologies, Universitat Jaume I, Avda. Sos Baynat s/n, 12071 Castellón, Spain
| | - Mahdy M. Elmahdy
- Department of Physics, Faculty of Science, Mansoura University, 35516 Mansoura, Egypt
| | - Mohamed Elsayed
- Department of Physics, Martin Luther University Halle, 06099 Halle, Germany
- Department of Physics, Faculty of Science, Minia University, 61519 Minia, Egypt
| | | | - Friedrich Kremer
- Peter-Debye-Institute, University of Leipzig, Linnéstraße 5, 04103 Leipzig, Germany
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186
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DeFelice J, Lipson JEG. Different metrics for connecting mobility and glassiness in thin films. SOFT MATTER 2019; 15:1651-1657. [PMID: 30676595 DOI: 10.1039/c8sm02355g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Data continue to accrue indicating that experimental techniques may differ in their sensitivity to mobility and glassiness. In this work the Limited Mobility (LM) kinetic model is used to show that two metrics for tracking sample mobility yield quantitatively different results for the glass transition and mobile layer thickness in systems where free surfaces are present. Both LM metrics track the fraction of material that embodies mobile free volume; in one it is relative to that portion of the sample containing any kind (mobile and dormant) of free volume, and in the other it is relative to the overall sample. Without any kind of optimization, use of the latter metric leads to semi-quantitative agreement with experimental film results, both for the mobile layer thickness and the dependence of sample glass transition temperature on film thickness. Connecting the LM predictions with experiment also produces a semi-quantitative mapping between LM model length and temperature scales, and those of real systems.
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Affiliation(s)
- Jeffrey DeFelice
- Department of Chemistry, Dartmouth College, Hanover, NH 03755, USA.
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187
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Thees MF, Roth CB. Unexpected Molecular Weight Dependence to the Physical Aging of Thin Polystyrene Films Present at Ultra‐High Molecular Weights. ACTA ACUST UNITED AC 2019. [DOI: 10.1002/polb.24797] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Connie B. Roth
- Department of Physics Emory University Atlanta Georgia 30322
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188
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Szymoniak P, Madkour S, Schönhals A. Molecular Dynamics of the Asymmetric Blend PVME/PS Revisited by Broadband Dielectric and Specific Heat Spectroscopy: Evidence of Multiple Glassy Dynamics. Macromolecules 2019. [DOI: 10.1021/acs.macromol.8b02697] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Paulina Szymoniak
- Bundesanstalt für Materialforschung und
-prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany
| | - Sherif Madkour
- Bundesanstalt für Materialforschung und
-prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany
| | - Andreas Schönhals
- Bundesanstalt für Materialforschung und
-prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany
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189
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Zhang C, Davies M, Karan K. Probing interfacial interactions of nafion ionomer: Thermal expansion of nafion thin films on substrates of different hydrophilicity/hydrophobicity. ACTA ACUST UNITED AC 2019. [DOI: 10.1002/polb.24792] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Chi Zhang
- Department of Chemical and Petroleum Engineering; The University of Calgary; 2500 University Dr. NW, Calgary Alberta T2N 1N4 Canada
| | - Michael Davies
- Department of Mechanical and Manufacturing Engineering; The University of Calgary; 2500 University Dr. NW, Calgary Alberta T2N 1N4 Canada
| | - Kunal Karan
- Department of Chemical and Petroleum Engineering; The University of Calgary; 2500 University Dr. NW, Calgary Alberta T2N 1N4 Canada
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190
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Phan AD, Schweizer KS. Theory of the spatial transfer of interface-nucleated changes of dynamical constraints and its consequences in glass-forming films. J Chem Phys 2019; 150:044508. [PMID: 30709240 DOI: 10.1063/1.5079250] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We formulate a new theory for how caging constraints in glass-forming liquids at a surface or interface are modified and then spatially transferred, in a layer-by-layer bootstrapped manner, into the film interior in the context of the dynamic free energy concept of the Nonlinear Langevin Equation (NLE) theory approach. The dynamic free energy at any mean location (cage center) involves contributions from two adjacent layers where confining forces are not the same. At the most fundamental level of the theory, the caging component of the dynamic free energy varies essentially exponentially with distance from the interface, saturating deep enough into the film with a correlation length of modest size and weak sensitivity to the thermodynamic state. This imparts a roughly exponential spatial variation of all the key features of the dynamic free energy required to compute gradients of dynamical quantities including the localization length, jump distance, cage barrier, collective elastic barrier, and alpha relaxation time. The spatial gradients are entirely of dynamical, not structural or thermodynamic, origin. The theory is implemented for the hard sphere fluid and diverse interfaces which can be a vapor, a rough pinned particle solid, a vibrating (softened) pinned particle solid, or a smooth hard wall. Their basic description at the level of the spatially heterogeneous dynamic free energy is identical, with the crucial difference arising from the first layer where dynamical constraints can be weakened, softened, or hardly changed depending on the specific interface. Numerical calculations establish the spatial dependence and fluid volume fraction sensitivity of the key dynamical property gradients for five different model interfaces. A comparison of the theoretical predictions for the dynamic localization length and glassy modulus with simulations and experiments for systems with a vapor interface reveals good agreement. The present advance sets the stage for using the Elastically Collective NLE theory to make quantitative predictions for the alpha relaxation time gradient, decoupling phenomena, Tg gradient, and many film-averaged properties of both model and experimental (colloids, molecules, and polymers) systems with diverse interfaces and chemical makeup.
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Affiliation(s)
- Anh D Phan
- Department of Physics, University of Illinois, Urbana, Illinois 61801, USA
| | - Kenneth S Schweizer
- Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
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191
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Smith SM, Simmons DS. Poisson ratio mismatch drives low-strain reinforcement in elastomeric nanocomposites. SOFT MATTER 2019; 15:656-670. [PMID: 30617354 DOI: 10.1039/c8sm02333f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Introduction of nanoparticulate additives can dramatically impact elastomer mechanical response, with large enhancements in modulus, toughness, and strength. Despite the societal importance of these effects, their mechanistic origin remains unsettled. Here, using a combination of theory and molecular dynamics simulation, we show that low-strain extensional reinforcement of elastomers is driven by a nanoparticulate-jamming-induced suppression in the composite Poisson ratio. This suppression forces an increase in rubber volume with extensional deformation, effectively converting a portion of the rubber's bulk modulus into an extensional modulus. A theory describing this effect is shown to interrelate the Poisson ratio and modulus across a matrix of simulated elastomeric nanocomposites of varying loading and nanoparticle structure. This model provides a design rule for structured nanoparticulates that maximizes elastomer mechanical response via suppression of the composite Poisson ratio. It also positions elastomeric nanocomposites as having a qualitatively different character than Poisson-ratio-matched plastic nanocomposites, where this mechanism is absent.
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Affiliation(s)
- Scott M Smith
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325, USA
| | - David S Simmons
- Department of Chemical and Biomedical Engineering, University of South Florida, Tampa, Florida 33620, USA.
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192
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Debot A, White RP, Lipson JEG, Napolitano S. Experimental Test of the Cooperative Free Volume Rate Model under 1D Confinement: The Interplay of Free Volume, Temperature, and Polymer Film Thickness in Driving Segmental Mobility. ACS Macro Lett 2019; 8:41-45. [PMID: 35619409 DOI: 10.1021/acsmacrolett.8b00844] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We show that the Cooperative Free Volume (CFV) rate model, successful at modeling pressure-dependent dynamics, can be employed to describe the temperature and thickness dependence of the segmental time of polymers confined in thin films (1D confinement). The CFV model is based on an activation free energy that increases with the number of cooperating segments, which is determined by the system's free volume. Here, we apply the CFV model to new experimental results on the segmental relaxation of 1D confined poly(4-chlorostyrene), P4ClS, and find remarkable agreement over the whole temperature and thickness ranges investigated. This work further validates the robustness of the CFV model, which relates the effects of confinement on dynamics to pressure changes in the bulk, and supports the idea that confinement effects originate from local perturbations in density.
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Affiliation(s)
- Alice Debot
- Polymer and Soft Matter Dynamics, Faculté des Sciences, Université libre de Bruxelles (ULB), Brussels, Belgium
| | - Ronald P. White
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Jane E. G. Lipson
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Simone Napolitano
- Polymer and Soft Matter Dynamics, Faculté des Sciences, Université libre de Bruxelles (ULB), Brussels, Belgium
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193
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Glass transition at the polystyrene/polyethylene glycol interface observed via contact angle measurements. Polym J 2019. [DOI: 10.1038/s41428-018-0163-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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194
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Pastore R, David A, Casalegno M, Greco F, Raos G. Influence of wall heterogeneity on nanoscopically confined polymers. Phys Chem Chem Phys 2019; 21:772-779. [PMID: 30548037 DOI: 10.1039/c8cp06757k] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We investigate via molecular dynamics simulations the behaviour of a polymer melt confined between surfaces with increasing spatial correlation (patchiness) of weakly and strongly interacting sites. Beyond a critical patchiness, we find a dramatic dynamic decoupling, characterized by a steep growth of the longest relaxation time and a constant diffusion coefficient. This arises from dynamic heterogeneities induced by the walls in the adjacent polymer layers, leading to the coexistence of fast and slow chain populations. Structural variations are also present, but they are not easy to detect. Our work opens the way to a better understanding of adhesion, friction, rubber reinforcement by fillers, and many other open issues involving the dynamics of polymeric materials on rough, chemically heterogeneous and possibly "dirty" surfaces.
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Affiliation(s)
- Raffaele Pastore
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, Napoli 80125, Italy.
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195
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Erwin AJ, Lee H, Ge S, Zhao S, Korolovych VF, He H, Matyjaszewski K, Sokolov AP, Tsukruk VV. Viscoelastic properties and ion dynamics in star-shaped polymerized ionic liquids. Eur Polym J 2018. [DOI: 10.1016/j.eurpolymj.2018.09.056] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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196
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Diaz-Vela D, Hung JH, Simmons DS. Temperature-Independent Rescaling of the Local Activation Barrier Drives Free Surface Nanoconfinement Effects on Segmental-Scale Translational Dynamics near Tg. ACS Macro Lett 2018; 7:1295-1301. [PMID: 35651251 DOI: 10.1021/acsmacrolett.8b00695] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Near-interface alterations in dynamics and glass formation behavior have been the subject of extensive study for the past two decades, both because of their practical importance and in the hope of revealing underlying correlation lengths underpinning glass transition more generally. Here we employ molecular dynamics simulations of thick films to demonstrate that these effects emerge, for segmental-scale translational dynamics at low temperature, from a temperature-independent rescaling of the local activation barrier. This rescaling manifests as a fractional power law decoupling relationship of local dynamics relative to the bulk, with a transition from a regime of weak decoupling at high temperatures to a regime of strong decoupling at low temperatures. The range of this effect saturates at low temperatures, with 90% of the surface perturbation in the barrier lost over a range of 12 segmental diameters. These findings reduce the phenomenology of Tg nanoconfinement effects to two properties-a position-dependent, temperature independent, barrier rescaling factor and an onset time scale-while substantially constraining the predictions required from any theoretical explanation of this phenomenon.
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Affiliation(s)
- Daniel Diaz-Vela
- The University of Akron, 250 South Forge Street, Akron, Ohio 44325, United States
| | - Jui-Hsiang Hung
- The University of Akron, 250 South Forge Street, Akron, Ohio 44325, United States
| | - David S. Simmons
- The University of South Florida, 4202 East Fowler Avenue, ENB 118, Tampa, Florida 33620, United States
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197
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Zhang Y, Woods CN, Alvarez M, Jin Y, Riggleman RA, Fakhraai Z. Effect of substrate interactions on the glass transition and length-scale of correlated dynamics in ultra-thin molecular glass films. J Chem Phys 2018; 149:184902. [PMID: 30441931 DOI: 10.1063/1.5038174] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Interfacial interactions can play an important role in the glass transition temperature (T g ) and relaxation dynamics of ultra-thin glass polymer films. We have recently shown that similar to the polymeric systems in ultra-thin molecular glass films of N, N'-Bis(3-methylphenyl)-N, N'-diphenylbenzidine (TPD), the T g is reduced and dynamics are enhanced. Furthermore, in molecular glass systems, as the film thickness is reduced below ∼30 nm, the dynamics at the two interfaces correlate such that the range of the gradients in the dynamics induced by the free surface narrows compared to thicker films. These observations indicate that the dynamics of the glassy thin films are strongly correlated and cannot be explained by a simple two-layer model consisting of a bulk and a thin interfacial layer with a constant thickness and constant range of dynamical gradients. Here, we investigate the effect of film/substrate interactions on the film dynamics by varying the TPD/substrate interfacial interactions. We show that thin TPD films with thicknesses below ∼60 nm show a smaller extent of T g reduction and enhanced dynamics when supported on a near-neutral substrate (wetting) compared to a weakly interacting (dewetting) substrate. However, the ∼30 nm length scale, where the activation energy significantly reduces from its bulk value as measured by the onset of the glass transition remains unchanged. Coarse-grained molecular dynamics simulation also shows a narrowing in the range of relaxation times once the thickness is sufficiently reduced for the two interfaces to dynamically correlate, consistent with previous work. These results suggest that the length-scale for the correlated dynamics is independent of interfacial interactions and the polymeric nature of the film and may originate from the bulk glass properties.
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Affiliation(s)
- Yue Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Connor N Woods
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Mauricio Alvarez
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Yi Jin
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Robert A Riggleman
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6315, USA
| | - Zahra Fakhraai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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Zargarian SS, Haddadi-Asl V, Kafrashian Z, Azarnia M, Mirhosseini MM, Seyedjafari E. Surfactant-assisted-water-exposed versus surfactant-aqueous-solution-exposed electrospinning of novel super hydrophilic polycaprolactone based fibers: Analysis of drug release behavior. J Biomed Mater Res A 2018; 107:597-609. [PMID: 30417973 DOI: 10.1002/jbm.a.36575] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/22/2018] [Accepted: 10/27/2018] [Indexed: 11/08/2022]
Abstract
Surface hydrophilicity and scaffold integrity determine the drug release behavior of drug loaded electrospun fibrous mats. When mixture miscibility is acceptable, blend electrospinning of hydrophobic with hydrophilic polymers can improve scaffold hydrophilicity while the hydrophobic polymer maintains the mechanical strength of scaffold. Polycaprolactone (PCL) and Pluronic P123 (P123) blend electrospinning has been investigated. In routine blend electrospinning, surface enrichment of Pluronic sets a limit for P123 weight ratio in which exceeding from that limit causes the excess P123 to be accumulated within the electrospun fiber core. To overcome this setback, a method named surfactant assisted water exposed (SAWE) electrospinning was introduced which was proven to be effective for increasing the surface enrichment of Pluronic. In order to test the validity of this method, the electrospinning of solution containing PCL which is exposed to aqueous solution of P123 was investigated. This new method was named surfactant aqueous solution exposed (SASE) electrospinning. Myelin formation at the contact interface of aqueous solution and chloroform solution was studied and it was found that this layer can effectively barricade the migration of Pluronic chains between immiscible phases. For SASE, fiber surface coverage by P123 was uneven and loose. Electrospun scaffolds from SAWE and SASE were loaded with drug to investigate the effect of the exposure time during electrospinning on in vitro drug release. By increasing the exposure time, the abnormal two-stage phased release profile of SAWE became normal with moderate initial burst. Longer exposure time increased the initial burst of the drug loaded SASE fibers. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 597-609, 2019.
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Affiliation(s)
- Seyed Shahrooz Zargarian
- Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran, Iran
| | - Vahid Haddadi-Asl
- Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran, Iran
| | - Zahra Kafrashian
- Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran, Iran
| | - Mojdeh Azarnia
- Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran, Iran
| | | | - Ehsan Seyedjafari
- Department of Biotechnology, College of Science, University of Tehran, Tehran, Iran
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199
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Becchi M, Giuntoli A, Leporini D. Molecular layers in thin supported films exhibit the same scaling as the bulk between slow relaxation and vibrational dynamics. SOFT MATTER 2018; 14:8814-8820. [PMID: 30346009 DOI: 10.1039/c8sm01891j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We perform molecular-dynamics simulations of a supported molecular thin film. By varying thickness and temperature, we observe anisotropic mobility as well as strong gradients of both the vibrational motion and the structural relaxation through film layers with monomer-size thickness. We show that the gradients of the fast and the slow dynamics across the layers (except the adherent layer to the substrate) comply, without any adjustment, with the same scaling between the structural relaxation time and the Debye-Waller factor originally observed in the bulk [Larini et al., Nat. Phys., 2008, 4, 42]. The scaling is not observed if the average dynamics of the film is inspected. Our results suggest that the solidification process of each layer may be tracked by knowing solely the vibrational properties of the layer and the bulk.
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Affiliation(s)
- Matteo Becchi
- Dipartimento di Fisica "E. Fermi", Università di Pisa, Largo B. Pontecorvo 3, Pisa, I-56127, Italy.
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200
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Lam CH. Deeper penetration of surface effects on particle mobility than on hopping rate in glassy polymer films. J Chem Phys 2018; 149:164909. [PMID: 30384677 DOI: 10.1063/1.5052659] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Chi-Hang Lam
- Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong, China
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