1
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Serna S, Wang T, Torkelson JM. Eliminating the Tg-confinement and fragility-confinement effects in poly(4-methylstyrene) films by incorporation of 3 mol % 2-ethylheyxl acrylate comonomer. J Chem Phys 2024; 160:034903. [PMID: 38235797 DOI: 10.1063/5.0189409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 12/22/2023] [Indexed: 01/19/2024] Open
Abstract
Nanoconfined poly(4-methylstyrene) [P(4-MS)] films exhibit reductions in glass transition temperature (Tg) relative to bulk Tg (Tg,bulk). Ellipsometry reveals that 15-nm-thick P(4-MS) films supported on silicon exhibit Tg - Tg,bulk = - 15 °C. P(4-MS) films also exhibit fragility-confinement effects; fragility decreases ∼60% in going from bulk to a 20-nm-thick film. Previous research found that incorporating 2-6 mol % 2-ethylhexyl acrylate (EHA) comonomer in styrene-based random copolymers eliminates Tg- and fragility-confinement effects in polystyrene. Here, we demonstrate that incorporating 3 mol % EHA in a 4-MS-based random copolymer, 97/3 P(4-MS/EHA), eliminates the Tg- and fragility-confinement effects. The invariance of fragility with nanoconfinement of 97/3 P(4-MS/EHA) films, hypothesized to originate from the interdigitation of ethylhexyl groups, indicates that the presence of EHA prevents the free surface from perturbing chain packing and the cooperative mobility associated with Tg. This method of eliminating confinement effects is advantageous as it relies on the simplest of polymerization methods and neat copolymer only slightly altered in composition from homopolymer. We also investigated whether we could eliminate the Tg-confinement effect with low levels of 2-ethylhexyl methacrylate (EHMA) in 4-MS-based or styrene-based copolymers. Although EHMA is structurally nearly identical to EHA, 4-MS-based and styrene-based copolymers incorporating 4 mol % EHMA exhibit Tg-confinement effects similar to P(4-MS) and polystyrene. These results support the special character of EHA in eliminating confinement effects originating at free surfaces.
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Affiliation(s)
- Sergio Serna
- Department of Chemical and Biological Engineering, Evanston, Illinois 60208, USA
| | - Tong Wang
- Department of Chemical and Biological Engineering, Evanston, Illinois 60208, USA
| | - John M Torkelson
- Department of Chemical and Biological Engineering, Evanston, Illinois 60208, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
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2
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Yin J, Forrest JA. Film Thickness Dependent Stability and Glass Transition Temperature of Polymer Films Produced by Physical Vapor Deposition. PHYSICAL REVIEW LETTERS 2023; 130:168101. [PMID: 37154633 DOI: 10.1103/physrevlett.130.168101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 02/12/2023] [Accepted: 03/17/2023] [Indexed: 05/10/2023]
Abstract
We report measurements of the onset temperature of rejuvenation, T_{onset}, and the fictive temperature, T_{f}, for ultrathin stable polystyrene with thicknesses from 10 to 50 nm prepared by physical vapor deposition. We also measure the T_{g} of these glasses on the first cooling after rejuvenation as well as the density anomaly of the as-deposited material. Both the T_{g} in rejuvenated films and the T_{onset} in stable films decrease with decreasing film thickness. The T_{f} value increases for decreasing film thickness. The density increase typical of stable glasses also decreases with decreasing film thickness. Collectively, the results are consistent with a decrease in apparent T_{g} due to the existence of a mobile surface layer, as well as a decrease in the film stability as the thickness is decreased. The results provide the first self-consistent set of measurements of stability in ultrathin films of stable glass.
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Affiliation(s)
- Junjie Yin
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
| | - James A Forrest
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
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3
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Madhusudanan M, Sarkar J, Dhar S, Chowdhury M. Tuning the Plasticization to Decouple the Effect of Molecular Recoiling Stress from Modulus and Viscosity in Dewetting Thin Polystyrene Films. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c02093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Affiliation(s)
- Mithun Madhusudanan
- Lab of Soft Interfaces, Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
| | - Jotypriya Sarkar
- Lab of Soft Interfaces, Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
| | - Sudeshna Dhar
- Lab of Soft Interfaces, Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
| | - Mithun Chowdhury
- Lab of Soft Interfaces, Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
- Center for Research in Nano Technology and Science, Indian Institute of Technology Bombay, Mumbai400076, Maharashtra, India
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4
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Wang T, Hu S, Zhang S, Peera A, Reffner J, Torkelson JM. Eliminating the Tg-Confinement Effect in Polystyrene Films: Extraordinary Impact of a 2 mol % 2-Ethylhexyl Acrylate Comonomer. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tong Wang
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois60208, United States
| | - Sumeng Hu
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois60208, United States
| | - Sipei Zhang
- The Dow Chemical Company, 400 Arcola Road, Collegeville, Pennsylvania19426, United States
| | - Asghar Peera
- The Dow Chemical Company, 400 Arcola Road, Collegeville, Pennsylvania19426, United States
| | - John Reffner
- The Dow Chemical Company, 400 Arcola Road, Collegeville, Pennsylvania19426, United States
| | - John M. Torkelson
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois60208, United States
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois60208, United States
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5
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Randazzo K, Bartkiewicz M, Graczykowski B, Cangialosi D, Fytas G, Zuo B, Priestley RD. Direct Visualization and Characterization of Interfacially Adsorbed Polymer atop Nanoparticles and within Nanocomposites. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01557] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Katelyn Randazzo
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | | | - Bartlomiej Graczykowski
- Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznanskiego 2, Poznan 61-614, Poland
| | - Daniele Cangialosi
- Centro de Física de Materiales (CSIC-UPV/EHU), Paseo Manuel de Lardizábal 5, San Sebastián 20018, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián 20018, Spain
| | - George Fytas
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Biao Zuo
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - 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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6
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Gawek M, Madkour S, Szymoniak P, Radnik J, Schönhals A. Energy dependent XPS measurements on thin films of a poly(vinyl methyl ether)/polystyrene blend concentration profile on a nanometer resolution to understand the behavior of nanofilms. SOFT MATTER 2021; 17:6985-6994. [PMID: 34236377 DOI: 10.1039/d1sm00656h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The composition of the surface layer in dependence from the distance of the polymer/air interface in thin films with thicknesses below 100 nm of miscible polymer blends in a spatial region of a few nanometers is not investigated completely. Here, thin films of the blend poly(vinyl methyl ether) (PVME)/polystyrene (PS) with a composition of 25/75 wt% are investigated by Energy Resolved X-ray Photoelectron Spectroscopy (ER-XPS) at a synchrotron storage ring using excitation energies lower than 1 keV. By changing the energy of the photons the information depth is varied in the range from ca. 1 nm to 10 nm. Therefore, the PVME concentration could be estimated in dependence from the distance of the polymer/air interface for film thicknesses below 100 nm. Firstly, as expected for increasing information depth the PVME concentration decreases. Secondly, it was found that the PVME concentration at the surface has a complicated dependence on the film thickness. It increases with decreasing film thickness until 30 nm where a maximum is reached. For smaller film thicknesses the PVME concentration decreases. A simplified layer model is used to calculate the effective PVME concentration in the different spatial regions of the surface layer.
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Affiliation(s)
- Marcel Gawek
- Bundesanstalt für Materialforschung und - prüfung (BAM) (Fachbereich 6.6), Unter den Eichen 87, 12205 Berlin, Germany.
| | - Sherif Madkour
- Bundesanstalt für Materialforschung und - prüfung (BAM) (Fachbereich 6.6), Unter den Eichen 87, 12205 Berlin, Germany.
| | - Paulina Szymoniak
- Bundesanstalt für Materialforschung und - prüfung (BAM) (Fachbereich 6.6), Unter den Eichen 87, 12205 Berlin, Germany.
| | - Jörg Radnik
- Bundesanstalt für Materialforschung und - prüfung (BAM) (Fachbereich 6.6), Unter den Eichen 87, 12205 Berlin, Germany.
| | - Andreas Schönhals
- Bundesanstalt für Materialforschung und - prüfung (BAM) (Fachbereich 6.6), Unter den Eichen 87, 12205 Berlin, Germany.
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7
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Chen H, Singhal G, Neubrech F, Liu R, Katz JS, Matteucci S, Arturo SG, Wasserman D, Giessen H, Braun PV. Measuring Molecular Diffusion Through Thin Polymer Films with Dual-Band Plasmonic Antennas. ACS NANO 2021; 15:10393-10405. [PMID: 34008953 DOI: 10.1021/acsnano.1c02701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A general and quantitative method to characterize molecular transport in polymers with good temporal and high spatial resolution, in complex environments, is an important need of the pharmaceutical, textile, and food and beverage packaging industries, and of general interest to the polymer science community. Here we show how the amplified infrared (IR) absorbance sensitivity provided by plasmonic nanoantenna-based surface enhanced infrared absorption (SEIRA) provides such a method. SEIRA enhances infrared (IR) absorbances primarily within 50 nm of the nanoantennas, enabling localized quantitative detection of even trace quantities of analytes and diffusion measurements in even thin polymer films. Relative to a commercial attenuated total internal reflection (ATR) system, the limit of detection is enhanced at least 13-fold, and as is important for measuring diffusion, the detection volume is about 15 times thinner. Via this approach, the diffusion coefficient and solubility of specific molecules, including l-ascorbic acid (vitamin C), ethanol, various sugars, and water, in both simple and complex mixtures (e.g., beer and a cola soda), were determined in poly(methyl methacrylate), high density polyethylene (HDPE)-based, and polypropylene-based polyolefin films as thin as 250 nm.
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Affiliation(s)
- Hao Chen
- Department of Material Science and Engineering, Materials Research Laboratory, and Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Gaurav Singhal
- Department of Material Science and Engineering, Materials Research Laboratory, and Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Frank Neubrech
- 2nd Physics Institute, Stuttgart University, Pfaffenwaldring 57, 70569 Stuttgart, Germany
- Max-Planck-Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Runyu Liu
- Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Joshua S Katz
- Formulation Science, Corporate Research and Development, The Dow Chemical Company, Collegeville, Pennsylvania 19426, United States
| | - Scott Matteucci
- Formulation Science, Corporate Research and Development, The Dow Chemical Company, Midland, Michigan 48674, United States
| | - Steven G Arturo
- Engineering and Process Sciences, Corporate Research and Development, The Dow Chemical Company, Collegeville, Pennsylvania 19426, United States
| | - Daniel Wasserman
- Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Harald Giessen
- 2nd Physics Institute, Stuttgart University, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - Paul V Braun
- Department of Material Science and Engineering, Materials Research Laboratory, and Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
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8
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DeFelice J, Lipson JEG. The influence of additives on polymer matrix mobility and the glass transition. SOFT MATTER 2021; 17:376-387. [PMID: 33169780 DOI: 10.1039/d0sm01634a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In the region near an interface, the microscopic properties of a glass forming liquid may be perturbed from their equilibrium bulk values. In this work, we probe how the interfacial effects of additive particles dispersed in a matrix can influence the local mobility of the material and its glass transition temperature, Tg. Experimental measurements and simulation results indicate that additives, such as nanoparticles, gas molecules, and oligomers, can shift the mobility and Tg of a surrounding polymer matrix (even for relatively small concentrations of additive; e.g., 5-10% by volume) relative to the pure bulk matrix, thus leading to Tg enhancement or suppression. Additives thus provide a potential route for modifying the properties of a polymer material without significantly changing its chemical composition. Here we apply the Limited Mobility (LM) model to simulate a matrix containing additive species. We show that both additive concentration, as well as the strength of its very local influence on the surrounding matrix material, will determine whether the Tg of the system is raised or lowered, relative to the pure matrix. We demonstrate that incorporation of additives into the simple LM simulation method, which has successfully described the behavior of bulk and thin film glassy solids, leads to direct connections with available experimental and simulation results for a broad range of polymer/additive systems.
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Affiliation(s)
- Jeffrey DeFelice
- Department of Chemistry, Dartmouth College, Hanover, NH 03755, USA.
| | - Jane E G Lipson
- Department of Chemistry, Dartmouth College, Hanover, NH 03755, USA.
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9
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Storey AN, Zhang W, Douglas JF, Starr FW. How Does Monomer Structure Affect the Interfacial Dynamics of Supported Ultrathin Polymer Films? Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c01413] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Amber N. Storey
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459-0155, United States
| | - Wengang Zhang
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459-0155, United States
- Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Jack F. Douglas
- Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Francis W. Starr
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459-0155, United States
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10
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Jung J, Kwon T, Oh Y, Lee YR, Sung BJ. Spatial Dependence of Non-Gaussian Diffusion of Nanoparticles in Free-Standing Thin Polymer Films. J Phys Chem B 2019; 123:9250-9259. [PMID: 31589036 DOI: 10.1021/acs.jpcb.9b07236] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The addition of nanoparticles (NPs) to a free-standing polymer film affects the properties of the film such as viscosity and glass transition temperature. Recent experiments, for example, showed that the glass transition temperature of thin polymer films was dependent on how NPs were distributed within the polymer films. However, the spatial arrangement of NPs in free-standing polymer films and its effect on the diffusion of NPs and polymers remain elusive at a molecular level. In this study, we employ generic coarse-grained models for polymers and NPs and perform extensive molecular dynamics simulations to investigate the diffusion of polymers and NPs in free-standing thin polymer films. We find that small NPs are likely to stay at the interfacial region of the polymer film, while large NPs tend to stay at the center of the film. On the other hand, as the interaction between a NP and a monomer becomes more attractive, the NP is more likely to be placed at the film center. The diffusion of monomers slows down slightly as more NPs are added to the film. Interestingly, the NP diffusion is dependent strongly on the spatial arrangement of the NPs: NPs at the interfacial region diffuse faster and undergo more non-Gaussian diffusion than NPs at the film center, which implies that the interfacial region would be more mobile and dynamically heterogeneous than the film center. We also find that the mechanism for non-Gaussian diffusion of NPs at the film center differs from that at the interfacial region and that the NP diffusion would reflect the local viscosity of the polymer films.
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Affiliation(s)
- Jinkwan Jung
- Department of Chemistry , Sogang University , Seoul 04107 , Republic of Korea
| | - Taejin Kwon
- Department of Chemistry , Sogang University , Seoul 04107 , Republic of Korea
| | - Younghoon Oh
- Department of Chemistry , Sogang University , Seoul 04107 , Republic of Korea
| | - Young-Ro Lee
- Department of Chemistry , Sogang University , Seoul 04107 , Republic of Korea
| | - Bong June Sung
- Department of Chemistry , Sogang University , Seoul 04107 , Republic of Korea
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11
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Choi J, Lee S, Choe J, Chung Y, Lee YE, Kim J, Kim M, Paeng K. How Tethered Probes Report the Dynamics of a Polymer near the Glass Transition. ACS Macro Lett 2019; 8:1181-1186. [PMID: 35619450 DOI: 10.1021/acsmacrolett.9b00423] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
How tethered probes report dynamics of host polymers near the glass transition was investigated by changing the length of the flexible linkers and the number of tethering points via imaging rotational fluorescence correlation microscopy and compared with free probes of different sizes. The results show that tethering did not alter the temperature-dependence of polymer dynamics and the shape of the correlation decay reported by the probe; however, the rotation slowed down up to ≈1 decade when both ends of the probe were restricted with short alkyl chain linkers. Upon comparison with the bigger free probe, the mechanism of the slowdown was attributed to the restricted motion upon tethering for tethered probes compared to averaging over different regions of the dynamic heterogeneity for the bigger probe. If the size of the probe was comparable to that of the dynamic heterogeneity of the system, tethered probes accurately report dynamics relevant to glass transition, regardless of tethering conditions.
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Affiliation(s)
- Jiwon Choi
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Soohyun Lee
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jongwon Choe
- Department of Chemistry and Chemical Engineering, Inha University, Incheon 22212, Republic of Korea
| | - Yura Chung
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Yae Eun Lee
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jisu Kim
- Department of Chemistry and Chemical Engineering, Inha University, Incheon 22212, Republic of Korea
| | - Myungwoong Kim
- Department of Chemistry and Chemical Engineering, Inha University, Incheon 22212, Republic of Korea
| | - Keewook Paeng
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
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12
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Xia W, Lan T. Interfacial Dynamics Governs the Mechanical Properties of Glassy Polymer Thin Films. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01235] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wenjie Xia
- Department of Civil & Environmental Engineering, North Dakota State University, Fargo, North Dakota 58108, United States
| | - Tian Lan
- Formulation, Automation & Materials Science, Core R&D, The Dow Chemical Company, 400 Arcola Rd., Collegeville, Pennsylvania 19426, United States
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13
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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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14
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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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15
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Xu J, Zhang H, Li J, Zhang L, Zuo B, Tsui OKC, Wang X. Conformation-Sensitive Surface Dynamics in Thin Poly(ethylene terephthalate) Film. Macromolecules 2019. [DOI: 10.1021/acs.macromol.8b02284] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Jianquan Xu
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Haosong Zhang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Jiachen Li
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Li Zhang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Biao Zuo
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Ophelia K. C. Tsui
- Department of Physics, Hong Kong University of Science & Technology, Clear Water Bay, Hong Kong, China
| | - Xinping Wang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
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16
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Xie W, Weng LT, Yeung KL, Chan CM. Segregation of dioctyl phthalate to the surface of polystyrene films characterized by ToF-SIMS and XPS. SURF INTERFACE ANAL 2018. [DOI: 10.1002/sia.6524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Wenjing Xie
- Division of Environment and Sustainability; Hong Kong University of Science and Technology; Clear Water Bay Hong Kong
| | - Lu-Tao Weng
- Department of Chemical and Biological Engineering; Hong Kong University of Science and Technology; Clear Water Bay Hong Kong
- Materials Characterization and Preparation Facility; Hong Kong University of Science and Technology; Clear Water Bay Hong Kong
| | - King Lun Yeung
- Division of Environment and Sustainability; Hong Kong University of Science and Technology; Clear Water Bay Hong Kong
- Department of Chemical and Biological Engineering; Hong Kong University of Science and Technology; Clear Water Bay Hong Kong
| | - Chi-Ming Chan
- Division of Environment and Sustainability; Hong Kong University of Science and Technology; Clear Water Bay Hong Kong
- Department of Chemical and Biological Engineering; Hong Kong University of Science and Technology; Clear Water Bay Hong Kong
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17
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Talik A, Tarnacka M, Grudzka-Flak I, Maksym P, Geppert-Rybczynska M, Wolnica K, Kaminska E, Kaminski K, Paluch M. The Role of Interfacial Energy and Specific Interactions on the Behavior of Poly(propylene glycol) Derivatives under 2D Confinement. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00658] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Agnieszka Talik
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center of Education and Interdisciplinary Research, University of Silesia, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
| | - Magdalena Tarnacka
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center of Education and Interdisciplinary Research, University of Silesia, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
| | - Iwona Grudzka-Flak
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center of Education and Interdisciplinary Research, University of Silesia, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
| | - Paulina Maksym
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center of Education and Interdisciplinary Research, University of Silesia, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
| | | | - Kamila Wolnica
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center of Education and Interdisciplinary Research, University of Silesia, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
| | - Ewa Kaminska
- Department of Pharmacognosy and Phytochemistry, Medical University of Silesia in Katowice, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Jagiellonska 4, 41-200 Sosnowiec, Poland
| | - Kamil Kaminski
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
| | - Marian Paluch
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center of Education and Interdisciplinary Research, University of Silesia, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
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18
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Chakraborty K, Vijayan K, Brown AEX, Discher DE, Loverde SM. Glassy worm-like micelles in solvent and shear mediated shape transitions. SOFT MATTER 2018; 14:4194-4203. [PMID: 29744515 PMCID: PMC6174325 DOI: 10.1039/c8sm00080h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The glassiness of polymer melts is generally considered to be suppressed by small dimensions, added solvent, and heat. Here, we suggest that glassiness persists at the nanoscale in worm-like micelles composed of amphiphilic diblock copolymers of poly(ethylene oxide)-polystyrene (PS). The glassiness of these worms is indicated by a lack of fluorescence recovery after photobleaching as well as micron-length rigid segments separated by hinges. The coarse-grained molecular dynamics studies probe the dynamics of the PS in these glassy worms. Addition of an organic solvent promotes a transition from hinged to fully flexible worms and to spheres or vesicles. Simulation demonstrates two populations of organic solvent in the core of the micelle-a solvent 'pool' in the micelle core and a second population that accumulates at the interface between the core and the corona. The stable heterogeneity of the residual solvent could explain the unusual hinged rigidity, but solvent removal during shear-extension could be more effective and yield - as observed - nearly straight worms without hinges.
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Affiliation(s)
- Kaushik Chakraborty
- Department of Chemistry, College of Staten Island, The City University of New York, 2800 Victory Boulevard, Staten Island, New York 10314, USA.
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19
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Kelly GM, Elman JF, Jiang Z, Strzalka J, Albert JN. Thermal transitions in semi-crystalline polymer thin films studied via spectral reflectance. POLYMER 2018. [DOI: 10.1016/j.polymer.2018.04.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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20
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Ogieglo W, Ghanem B, Ma X, Wessling M, Pinnau I. High-Pressure CO 2 Sorption in Polymers of Intrinsic Microporosity under Ultrathin Film Confinement. ACS APPLIED MATERIALS & INTERFACES 2018; 10:11369-11376. [PMID: 29528618 DOI: 10.1021/acsami.8b01402] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Ultrathin microporous polymer films are pertinent to the development and further spread of nanotechnology with very promising potential applications in molecular separations, sensors, catalysis, or batteries. Here, we report high-pressure CO2 sorption in ultrathin films of several chemically different polymers of intrinsic microporosity (PIMs), including the prototypical PIM-1. Films with thicknesses down to 7 nm were studied using interference-enhanced in situ spectroscopic ellipsometry. It was found that all PIMs swell much more than non-microporous polystyrene and other high-performance glassy polymers reported previously. Furthermore, chemical modifications of the parent PIM-1 strongly affected the swelling magnitude. By investigating the behavior of relative refractive index, nrel, it was possible to study the interplay between micropores filling and matrix expansion. Remarkably, all studied PIMs showed a maximum in nrel at swelling of 2-2.5% indicating a threshold point above which the dissolution in the dense matrix started to dominate over sorption in the micropores. At pressures above 25 bar, all PIMs significantly plasticized in compressed CO2 and for the ones with the highest affinity to the penetrant, a liquidlike mixing typical for rubbery polymers was observed. Reduction of film thickness below 100 nm revealed pronounced nanoconfinement effects and resulted in a large swelling enhancement and a quick loss of the ultrarigid character. On the basis of the partial molar volumes of the dissolved CO2, the effective reduction of the Tg was estimated to be ∼200 °C going from 128 to 7 nm films.
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Affiliation(s)
- Wojciech Ogieglo
- DWI Leibniz Institute for Interactive Materials , Forckenbeckstr. 50 , 52074 Aachen , Germany
- Functional Polymer Membranes Group, Advanced Membranes and Porous Materials Center, Division of Physical Sciences and Engineering , King Abdullah University of Science and Technology (KAUST) , Thuwal, Jeddah 23955-6900 , Kingdom of Saudi Arabia
| | - Bader Ghanem
- Functional Polymer Membranes Group, Advanced Membranes and Porous Materials Center, Division of Physical Sciences and Engineering , King Abdullah University of Science and Technology (KAUST) , Thuwal, Jeddah 23955-6900 , Kingdom of Saudi Arabia
| | - Xiaohua Ma
- Functional Polymer Membranes Group, Advanced Membranes and Porous Materials Center, Division of Physical Sciences and Engineering , King Abdullah University of Science and Technology (KAUST) , Thuwal, Jeddah 23955-6900 , Kingdom of Saudi Arabia
| | - Matthias Wessling
- DWI Leibniz Institute for Interactive Materials , Forckenbeckstr. 50 , 52074 Aachen , Germany
| | - Ingo Pinnau
- Functional Polymer Membranes Group, Advanced Membranes and Porous Materials Center, Division of Physical Sciences and Engineering , King Abdullah University of Science and Technology (KAUST) , Thuwal, Jeddah 23955-6900 , Kingdom of Saudi Arabia
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21
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Bhattacharyya D, Paul S, Ghosh S, Ray DS. Brownian dynamics of self-regulated particles with additional degrees of freedom: Symmetry breaking and homochirality. Phys Rev E 2018; 97:042125. [PMID: 29758662 DOI: 10.1103/physreve.97.042125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Indexed: 06/08/2023]
Abstract
We consider the Brownian motion of a collection of particles each with an additional degree of freedom. The degree of freedom of a particle (or, in general, a molecule) can assume distinct values corresponding to certain states or conformations. The time evolution of the additional degree of freedom of a particle is guided by those of its neighbors as well as the temperature of the system. We show that the local averaging over these degrees of freedom results in emergence of a collective order in the dynamics in the form of selection or dominance of one of the isomers leading to a symmetry-broken state. Our statistical model captures the basic features of homochirality, e.g., autocatalysis and chiral inhibition.
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Affiliation(s)
| | - Shibashis Paul
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Shyamolina Ghosh
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Deb Shankar Ray
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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22
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Burroughs MJ, Christie D, Gray LAG, Chowdhury M, Priestley RD. 21st Century Advances in Fluorescence Techniques to Characterize Glass‐Forming Polymers at the Nanoscale. MACROMOL CHEM PHYS 2017. [DOI: 10.1002/macp.201700368] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Mary J. Burroughs
- Department of Chemical and Biological Engineering Princeton University Princeton NJ 08544 USA
| | - Dane Christie
- Department of Chemical and Biological Engineering Princeton University Princeton NJ 08544 USA
| | - Laura A. G. Gray
- Department of Chemical and Biological Engineering Princeton University Princeton NJ 08544 USA
| | - Mithun Chowdhury
- Department of Chemical and Biological Engineering Princeton University Princeton NJ 08544 USA
| | - Rodney D. Priestley
- Department of Chemical and Biological Engineering Princeton Institute for the Science and Technology of Materials Princeton University Princeton NJ 08544 USA
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23
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Kelly GM, Haque FM, Grayson SM, Albert JNL. Suppression of Melt-Induced Dewetting in Cyclic Poly(ε-caprolactone) Thin Films. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b02200] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Giovanni M. Kelly
- Department
of Chemical and Biomolecular Engineering and ‡Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Farihah M. Haque
- Department
of Chemical and Biomolecular Engineering and ‡Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Scott M. Grayson
- Department
of Chemical and Biomolecular Engineering and ‡Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Julie N. L. Albert
- Department
of Chemical and Biomolecular Engineering and ‡Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
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24
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Kasavan BL, Baglay RR, Roth CB. Local Glass Transition Temperature
T
g
(
z
) Profile in Polystyrene next to Polybutadiene with and without Plasticization Effects. MACROMOL CHEM PHYS 2017. [DOI: 10.1002/macp.201700328] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [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 GA 30322 USA
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25
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Du X, Tang X, Fang J, Zhu DM. Quartz crystal resonator study of glass transitions in polyvinylbutyral (PVB) films. J Appl Polym Sci 2017. [DOI: 10.1002/app.45433] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Xianbin Du
- State Key Laboratory of Particle Detection and Electronics; University of Science and Technology of China; Hefei China
- Department of Modern Physics; University of Science and Technology of China; Hefei China
| | - Xuefeng Tang
- State Key Laboratory of Particle Detection and Electronics; University of Science and Technology of China; Hefei China
- Department of Modern Physics; University of Science and Technology of China; Hefei China
| | - Jiajie Fang
- State Key Laboratory of Particle Detection and Electronics; University of Science and Technology of China; Hefei China
- Department of Modern Physics; University of Science and Technology of China; Hefei China
| | - Da-Ming Zhu
- State Key Laboratory of Particle Detection and Electronics; University of Science and Technology of China; Hefei China
- Department of Modern Physics; University of Science and Technology of China; Hefei China
- Department of Physics and Astronomy; University of Missouri-Kansas City; Kansas City Missouri 64110
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26
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Vogt BD. Mechanical and viscoelastic properties of confined amorphous polymers. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/polb.24529] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Bryan D. Vogt
- Department of Polymer Engineering; University of Akron; Akron Ohio 44325
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27
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Madkour S, Szymoniak P, Hertwig A, Heidari M, von Klitzing R, Napolitano S, Sferrazza M, Schönhals A. Decoupling of Dynamic and Thermal Glass Transition in Thin Films of a PVME/PS Blend. ACS Macro Lett 2017; 6:1156-1161. [PMID: 35650935 DOI: 10.1021/acsmacrolett.7b00625] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The discussions on the nanoconfinement effect on the glass transition and glassy dynamics phenomena have yielded many open questions. Here, the thickness dependence of the thermal glass transition temperature Tgtherm of thin films of a PVME/PS blend is investigated by ellipsometry. Its thickness dependence was compared to that of the dynamic glass transition (measured by specific heat spectroscopy) and the deduced Vogel temperature (T0). While Tgtherm and T0 showed a monotonous increase, with decreasing film thickness, the dynamic glass transition temperature (Tgdyn) measured at a finite frequency showed a nonmonotonous dependence that peaks at 30 nm. This was discussed by assuming different cooperativity length scales at these temperatures, which have different sensitivities to composition and thickness. This nonmonotonous thickness dependence of Tgdyn disappears for frequencies characteristic for T0. Further analysis of the fragility parameter showed a change in the glassy dynamics from strong to fragile, with decreasing film thickness.
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Affiliation(s)
- Sherif Madkour
- Bundesanstalt für Materialforschung und−prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany
| | - Paulina Szymoniak
- Bundesanstalt für Materialforschung und−prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany
| | - Andreas Hertwig
- Bundesanstalt für Materialforschung und−prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany
| | - Mojdeh Heidari
- Fachbereich
für Physik, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, 64287 Darmstadt, Germany
| | - Regine von Klitzing
- Fachbereich
für Physik, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, 64287 Darmstadt, Germany
| | | | | | - Andreas Schönhals
- Bundesanstalt für Materialforschung und−prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany
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28
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Im H, Oh Y, Cho HW, Kim J, Paeng K, Sung BJ. The spatial arrangement of a single nanoparticle in a thin polymer film and its effect on the nanoparticle diffusion. SOFT MATTER 2017; 13:5897-5904. [PMID: 28766660 DOI: 10.1039/c7sm01115f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The spatial arrangement of nanoparticles (NPs) within thin polymer films may influence their properties such as the glass transition temperature. Questions regarding what may affect the spatial arrangement of NPs, however, still remain unanswered at a molecular level. In this work, we perform molecular dynamics simulations for a free-standing thin polymer film with a single NP. We find from simulations that depending on the NP size and the inter-particle interaction between the NP and polymers, one may control the spatial arrangement of the NP. When the interaction between the NP and polymers is sufficiently attractive (repulsive), the NP is likely to be placed at the center (at the surface) of the thin film in equilibrium. Interestingly, for a moderate interaction between the NP and polymers, the first-order transition occurs in the spatial arrangement of the NP as one increases the NP size: a small NP prefers the surface of the polymer film whereas a large NP prefers the center. Such a first-order transition is corroborated by calculating the free energy of the NP as a function of the position and can be understood in terms of a sixth-order Landau free energy. More interestingly, the diffusion of the NP also changes drastically due to the first-order transition in the spatial arrangement. The NP diffusion is enhanced drastically (more than expected in bulk polymer melts) as the NP is shifted to the polymer film surface.
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Affiliation(s)
- Hesang Im
- Department of Chemistry and Research Institute for Basic Science, Sogang University, Seoul 04107, Republic of Korea.
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29
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Mangalara JH, Mackura ME, Marvin MD, Simmons DS. The relationship between dynamic and pseudo-thermodynamic measures of the glass transition temperature in nanostructured materials. J Chem Phys 2017; 146:203316. [DOI: 10.1063/1.4977520] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Affiliation(s)
- Jayachandra Hari Mangalara
- Department of Polymer Engineering, The University of Akron, 250 South Forge St, Akron, Ohio, 44325-0301 USA
| | - Mark E. Mackura
- Department of Polymer Engineering, The University of Akron, 250 South Forge St, Akron, Ohio, 44325-0301 USA
| | - Michael D. Marvin
- Department of Polymer Engineering, The University of Akron, 250 South Forge St, Akron, Ohio, 44325-0301 USA
| | - David S. Simmons
- Department of Polymer Engineering, The University of Akron, 250 South Forge St, Akron, Ohio, 44325-0301 USA
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30
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Russell TP, Chai Y. 50th Anniversary Perspective: Putting the Squeeze on Polymers: A Perspective on Polymer Thin Films and Interfaces. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b00418] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Thomas P. Russell
- Polymer
Science and Engineering Department, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
- Materials
Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
- Beijing
Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yu Chai
- Materials
Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
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31
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Mangalara JH, Marvin MD, Wiener NR, Mackura ME, Simmons DS. Does fragility of glass formation determine the strength ofTg-nanoconfinement effects? J Chem Phys 2017; 146:104902. [DOI: 10.1063/1.4976521] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Jayachandra Hari Mangalara
- Department of Polymer Engineering, The University of Akron, 250 South Forge Street, Akron, Ohio 44325-0301, USA
| | - Michael D. Marvin
- Department of Polymer Engineering, The University of Akron, 250 South Forge Street, Akron, Ohio 44325-0301, USA
| | - Nicholas R. Wiener
- Department of Polymer Engineering, The University of Akron, 250 South Forge Street, Akron, Ohio 44325-0301, USA
| | - Mark E. Mackura
- Department of Polymer Engineering, The University of Akron, 250 South Forge Street, Akron, Ohio 44325-0301, USA
| | - David S. Simmons
- Department of Polymer Engineering, The University of Akron, 250 South Forge Street, Akron, Ohio 44325-0301, USA
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32
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Hetayothin B, Cabaniss RA, Blum FD. Does Plasticizer Penetrate Tightly Bound Polymer in Adsorbed Poly(vinyl acetate) on Silica? Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b00022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Boonta Hetayothin
- Department of Chemistry and Biochemistry, California State University, Los
Angeles, California 90032, United States
| | | | - Frank D. Blum
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
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33
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Cho HW, Sung BJ. The glass transition and interfacial dynamics of single strand fibers of polymers. SOFT MATTER 2017; 13:1190-1199. [PMID: 28098313 DOI: 10.1039/c6sm02468h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigate the glass transition and interfacial dynamics of single strand fibers of flexible polymers by employing molecular dynamics (MD) simulations along with a coarse grained model. While the polymer fiber has drawn significant attention due to its applicability in tissue engineering and stretchable electronics, its dynamic properties, especially the glass transition temperature (Tg), are yet to be understood at the molecular level. For example, there has been a controversy on the effect of the polymer fiber radius (R) on Tg: Tg decreased with a decrease in R for some polymer fibers, whereas Tg of other polymer fibers was not sensitive to R. In this article, we estimate the bond relaxation time of polymers and evaluate both Tg and fragility (m) as a function of R. We illustrate that Tg of the polymer fiber decreased with a decrease in R monotonically and also that the values of Tg follow faithfully the empirical equation proposed by Keddie et al. as a function of R, which was successfully employed to fit the values of Tg of both polyvinyl alcohol (PVA) fibers and polyethylene (PE) fibers. We also find that the dynamics of polymers at the interface between a polymer fiber and air is faster than that of polymers at the center. By employing Adam-Gibbs theory, we show that the fast interface dynamics of polymer fibers should influence the cooperative motion of monomers, which should be responsible for the decrease in Tg for smaller values of R. Near the interface there are more mobile monomers that participate in the cooperative motions of polymers. Interesting is that due to the curved surface (unlike flat polymer films) the cooperative motion of monomers is anisotropic in polymer fibers.
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Affiliation(s)
- Hyun Woo Cho
- Department of Chemistry and Research Institute for Basic Science, Sogang University, Seoul 121-742, Republic of Korea.
| | - Bong June Sung
- Department of Chemistry and Research Institute for Basic Science, Sogang University, Seoul 121-742, Republic of Korea.
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34
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Ok S, Sheets J, Welch S, Kaya S, Jalilov A, Cole DR. Tuning hydrophobicity of a fluorinated terpolymer in differently assembled thin films. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/polb.24308] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Salim Ok
- School of Earth Sciences; The Ohio State University; Columbus Ohio 43210
| | - Julia Sheets
- School of Earth Sciences; The Ohio State University; Columbus Ohio 43210
| | - Susan Welch
- School of Earth Sciences; The Ohio State University; Columbus Ohio 43210
| | - Savas Kaya
- School of Electrical Engineering and Computer Science; Ohio University; Athens Ohio 45701
| | - Almaz Jalilov
- Department of Chemistry; Rice University; 6100 Main Street Houston Texas 77005
| | - David R. Cole
- School of Earth Sciences; The Ohio State University; Columbus Ohio 43210
- Department of Chemistry; The Ohio State University; Columbus Ohio 43210
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35
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Zhang L, Elupula R, Grayson SM, Torkelson JM. Suppression of the Fragility-Confinement Effect via Low Molecular Weight Cyclic or Ring Polymer Topology. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02280] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
| | - Ravinder Elupula
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Scott M. Grayson
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
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36
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Janes DW, Bilchak C, Durning CJ. Decoupling energetic modifications to diffusion from free volume in polymer/nanoparticle composites. SOFT MATTER 2017; 13:677-685. [PMID: 28009881 DOI: 10.1039/c6sm02172g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Diffusion coefficients of small molecules in a model composite of spherical nanoparticles and polymer with attractive interfacial interactions are reduced from that in the pure polymer, to a degree far below the level expected from geometric tortuosity arguments. We determine whether such dramatic reductions are due to modifications to the matrix polymer free volume near the nanoparticle surface, or alternatively are due to energetic attractions between the diffusants and nanoparticle surface. We performed ethyl acetate sorption experiments within the vicinity of the polymer glass transition (Tg ≤ T ≤ Tg + 25 K) for a model polymer/nanoparticle composite, silica-filled poly(methyl acrylate). By application of the Vrentas-Duda free volume theory of diffusion we have decoupled the energetic effects from those related to free-volume and segmental dynamics. While the latter is unaffected by addition of nanoparticles, the energy needed for the ethyl acetate diffusant to overcome neighboring attractive forces doubles after adding 40 vol% nanoparticles with a diameter of 14 nm. This is qualitatively consistent with hydrogen bonding interactions between the silica surface and ethyl acetate slowing its rate of diffusion. On the other hand for benzene, which does not hydrogen bond to the silica surface, diffusion coefficients that can be explained by tortuosity effects were obtained. This work provides quantitative evidence that the diffusant-filler energetic interactions and geometric blocking effects can be fully responsible for the substantially reduced diffusivity commonly observed in polymer/nanoparticle composite systems.
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Affiliation(s)
| | - Connor Bilchak
- Department of Chemical Engineering, Columbia University, New York, NY 10027, USA.
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37
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Tarnacka M, Kaminski K, Mapesa EU, Kaminska E, Paluch M. Studies on the Temperature and Time Induced Variation in the Segmental and Chain Dynamics in Poly(propylene glycol) Confined at the Nanoscale. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01237] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Magdalena Tarnacka
- Institute
of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
- Silesian
Center for Education and Interdisciplinary Research, University of Silesia, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
| | - Kamil Kaminski
- Institute
of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
| | - Emmanuel U. Mapesa
- Institute
of Experimental Physics I, University of Leipzig, Linnéstraße
5, 04103 Leipzig, Germany
| | - Ewa Kaminska
- Department
of Pharmacognosy and Phytochemistry, Medical University of Silesia in Katowice, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Jagiellonska 4, 41-200 Sosnowiec, Poland
| | - Marian Paluch
- Institute
of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
- Silesian
Center for Education and Interdisciplinary Research, University of Silesia, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
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38
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Burroughs MJ, Napolitano S, Cangialosi D, Priestley RD. Direct Measurement of Glass Transition Temperature in Exposed and Buried Adsorbed Polymer Nanolayers. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00400] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
| | - Simone Napolitano
- Laboratory
of Polymer and Soft Matter Dynamics Faculté des Sciences, Université Libre de Bruxelles (ULB), Boulevard du Triomphe, Bâtiment NO, Bruxelles 1050, Belgium
| | - Daniele Cangialosi
- Centro
de Física
de Materiales (CSIC-UPV/EHU), Paseo
Manuel de Lardizábal 5, San Sebastián 20018, Spain
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39
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Hsu DD, Xia W, Song J, Keten S. Glass-Transition and Side-Chain Dynamics in Thin Films: Explaining Dissimilar Free Surface Effects for Polystyrene vs Poly(methyl methacrylate). ACS Macro Lett 2016; 5:481-486. [PMID: 35607230 DOI: 10.1021/acsmacrolett.6b00037] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Despite having very similar bulk properties such as glass-transition temperature (Tg), density, and fragility, polystyrene (PS) and poly(methyl methacrylate) (PMMA) exhibit characteristically different Tg depression in free-standing ultrathin films due to free surface effects. Here we explain this difference using our recently established chemistry-specific coarse-grained (CG) models for these two polymers. Models capture the dissimilar scaling of Tg with free-standing film thickness as seen in experiments and enable us to quantify the size of the regions near free surfaces over which chain relaxation exhibits differences from bulk. Most interestingly, vibrational density of states (VDOS) analysis uncovers a relationship between the amplitude of side-chain fluctuations, associated with side-chain flexibility and Tg-nanoconfinement. We discover that increasing backbone to side-chain mass ratio in CG models increases the amplitude of side-chain fluctuations and suppresses the free-surface effect on Tg. We show that mass distribution and side-chain flexibility are central to explain dissimilar free surface effects on PS and PMMA. Our model predictions are further corroborated by experimental evidence showing the role of mass distribution in styrene thin films. Our study ascertains the significance of molecular characteristics on nanoconfinement and highlights the ability for chemistry-specific CG models to explore the thermomechanical properties of polymer thin films.
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Affiliation(s)
- David D. Hsu
- Department of Mechanical Engineering, ‡Department of Civil & Environmental Engineering, and §Department of Materials Science & Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3109, United States
| | - Wenjie Xia
- Department of Mechanical Engineering, ‡Department of Civil & Environmental Engineering, and §Department of Materials Science & Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3109, United States
| | - Jake Song
- Department of Mechanical Engineering, ‡Department of Civil & Environmental Engineering, and §Department of Materials Science & Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3109, United States
| | - Sinan Keten
- Department of Mechanical Engineering, ‡Department of Civil & Environmental Engineering, and §Department of Materials Science & Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3109, United States
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40
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Geng K, Tsui OKC. Effects of Polymer Tacticity and Molecular Weight on the Glass Transition Temperature of Poly(methyl methacrylate) Films on Silica. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00108] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Kun Geng
- Department
of Physics, Boston University, Boston, Massachusetts 02215, United States
| | - Ophelia K. C. Tsui
- Department
of Physics, Boston University, Boston, Massachusetts 02215, United States
- Division
of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, United States
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41
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Chen L, Torkelson JM. Tuning the Tg-confinement effect in thin polymer films via minute levels of residual surfactant which “cap” the free surface. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.02.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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42
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Lan T, Torkelson JM. Fragility-Confinement Effects: Apparent Universality as a Function of Scaled Thickness in Films of Freely Deposited, Linear Polymer and Its Absence in Densely Grafted Brushes. Macromolecules 2016. [DOI: 10.1021/acs.macromol.5b02489] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tian Lan
- Department of Materials Science
and Engineering and ‡Department of Chemical and Biological
Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - John M. Torkelson
- Department of Materials Science
and Engineering and ‡Department of Chemical and Biological
Engineering, Northwestern University, Evanston, Illinois 60208, United States
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43
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Kim HC, Lee H, Khetan J, Won YY. Surface Mechanical and Rheological Behaviors of Biocompatible Poly((D,L-lactic acid-ran-glycolic acid)-block-ethylene glycol) (PLGA-PEG) and Poly((D,L-lactic acid-ran-glycolic acid-ran-ε-caprolactone)-block-ethylene glycol) (PLGACL-PEG) Block Copolymers at the Air-Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:13821-13833. [PMID: 26633595 DOI: 10.1021/acs.langmuir.5b03622] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Air-water interfacial monolayers of poly((D,L-lactic acid-ran-glycolic acid)-block-ethylene glycol) (PLGA-PEG) exhibit an exponential increase in surface pressure under high monolayer compression. In order to understand the molecular origin of this behavior, a combined experimental and theoretical investigation (including surface pressure-area isotherm, X-ray reflectivity (XR) and interfacial rheological measurements, and a self-consistent field (SCF) theoretical analysis) was performed on air-water monolayers formed by a PLGA-PEG diblock copolymer and also by a nonglassy analogue of this diblock copolymer, poly((D,L-lactic acid-ran-glycolic acid-ran-caprolactone)-block-ethylene glycol) (PLGACL-PEG). The combined results of this study show that the two mechanisms, i.e., the glass transition of the collapsed PLGA film and the lateral repulsion of the PEG brush chains that occur simultaneously under lateral compression of the monolayer, are both responsible for the observed PLGA-PEG isotherm behavior. Upon cessation of compression, the high surface pressure of the PLGA-PEG monolayer typically relaxes over time with a stretched exponential decay, suggesting that in this diblock copolymer situation, the hydrophobic domain formed by the PLGA blocks undergoes glass transition in the high lateral compression state, analogously to the PLGA homopolymer monolayer. In the high PEG grafting density regime, the contribution of the PEG brush chains to the high monolayer surface pressure is significantly lower than what is predicted by the SCF model because of the many-body attraction among PEG segments (referred to in the literature as the "n-cluster" effects). The end-grafted PEG chains were found to be protein resistant even under the influence of the "n-cluster" effects.
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Affiliation(s)
- Hyun Chang Kim
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - Hoyoung Lee
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - Jawahar Khetan
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - You-Yeon Won
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
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44
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Udagawa A, Fujie T, Kawamoto Y, Saito A, Takeoka S, Asahi T. Interfacial effects on the crystallization and surface properties of poly(l-lactic acid) ultrathin films. Polym J 2015. [DOI: 10.1038/pj.2015.95] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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45
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Mangalara JH, Simmons DS. Tuning Polymer Glass Formation Behavior and Mechanical Properties with Oligomeric Diluents of Varying Stiffness. ACS Macro Lett 2015; 4:1134-1138. [PMID: 35614818 DOI: 10.1021/acsmacrolett.5b00635] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Small-molecule diluents are important tools in the control of polymers' glass formation, transport, and mechanical properties. While recent work has indicated that these diluents can impose a more diverse range of effects than previously appreciated, use of these additives to rationally control polymer properties requires a predictive understanding of their effects. Here we employ molecular dynamics simulations to show that diluent-induced changes in a polymer's glass transition temperature Tg can be predicted based on the diluent's Debye-Waller factor ⟨u2⟩, a measure of picosecond time scale rattle-space, via a functional form previously found to predict nanoconfinement-induced shifts in polymer Tg. Moreover, we show that diluent-induced alterations in polymer segmental relaxation time are related to changes in modulus and ⟨u2⟩ via the Generalized Localization Model of relaxation. These results provide new design principles for the use of oligomeric diluents in achieving independent, targeted control of structural relaxation and glassy moduli.
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Affiliation(s)
- Jayachandra Hari Mangalara
- Department
of Polymer Engineering, The University of Akron, 250 South Forge
Street, Akron, Ohio 44325-0301, United States
| | - David S. Simmons
- Department
of Polymer Engineering, The University of Akron, 250 South Forge
Street, Akron, Ohio 44325-0301, United States
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46
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Chen F, Peng D, Ogata Y, Tanaka K, Yang Z, Fujii Y, Yamada NL, Lam CH, Tsui OKC. Confinement Effect on the Effective Viscosity of Plasticized Polymer Films. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b01780] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- F. Chen
- Department
of Physics, Boston University, Boston, Massachusetts 02215, United States
| | - D. Peng
- Department
of Physics, Boston University, Boston, Massachusetts 02215, United States
| | - Y. Ogata
- Department
of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan
| | - K. Tanaka
- Department
of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan
| | - Z. Yang
- Department
of Polymer Science and Engineering, Soochow University, Suzhou, P. R. China
| | - Y. Fujii
- National Institute
for Materials Science, 1-1 Namiki, Tsukuba, Japan
| | - N. L. Yamada
- Neutron
Science Laboratory, High Energy Accelerator Research Organization, Ibaraki 305-0044, Japan
| | - C.-H. Lam
- Department
of Applied Physics, Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - O. K. C. Tsui
- Department
of Physics, Boston University, Boston, Massachusetts 02215, United States
- Division of Materials Science & Engineering, Boston University, Brookline, Massachusetts 02446, United States
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47
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Sanz A, Wong HC, Nedoma AJ, Douglas JF, Cabral JT. Influence of C60 fullerenes on the glass formation of polystyrene. POLYMER 2015. [DOI: 10.1016/j.polymer.2015.05.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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48
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Xie SJ, Qian HJ, Lu ZY. Polymer brushes: a controllable system with adjustable glass transition temperature of fragile glass formers. J Chem Phys 2015; 140:044901. [PMID: 25669577 DOI: 10.1063/1.4862234] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present results of molecular dynamics simulations for coarse-grained polymer brushes in a wide temperature range to investigate the factors that affect the glass transition in these systems. We focus on the influences of free surface, polymer-substrate interaction strength, grafting density, and chain length not only on the change of glass transition temperature Tg, but also the fragility D of the glass former. It is found that the confinement can enhance the dependence of the Tg on the cooling rate as compared to the bulk melt. Our layer-resolved analysis demonstrates that it is possible to control the glass transition temperature Tg of polymer brushes by tuning the polymer-substrate interaction strength, the grafting density, and the chain length. Moreover, we find quantitative differences in the influence range of the substrate and the free surface on the density and dynamics. This stresses the importance of long range cooperative motion in glass formers near the glass transition temperature. Furthermore, the string-like cooperative motion analysis demonstrates that there exists a close relation among glass transition temperature Tg, fragility D, and string length ⟨S⟩. The polymer brushes that possess larger string length ⟨S⟩ tend to have relatively higher Tg and smaller D. Our results suggest that confining a fragile glass former through forming polymer brushes changes not only the glass transition temperature Tg, but also the very nature of relaxation process.
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Affiliation(s)
- Shi-Jie Xie
- Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130023, China
| | - Hu-Jun Qian
- Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130023, China
| | - Zhong-Yuan Lu
- Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130023, China
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49
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Shavit A, Riggleman RA. Strain localization in glassy polymers under cylindrical confinement. Phys Chem Chem Phys 2015; 16:10301-9. [PMID: 24676009 DOI: 10.1039/c3cp55330b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Although the origin of ductility in crystalline materials is well understood through the motion of dislocations and defects, a similar framework for understanding deformation in amorphous materials remains elusive. In particular, the difference in the mechanical response for small-molecule amorphous solids, such as organic glasses that are typically brittle, and polymer glasses, which are frequently very tough, has not been systematically explored. Here, we employ molecular dynamics simulations to investigate the mechanical response of model glassy polymers confined to a nanoscopic pillar under tensile deformation. We vary the chain length, cooling rate for forming the glass, and the deformation rate and investigate the changes in the mechanical response. We find that samples that are cooled at a slower rate and deformed at a slower rate are more prone to localization of the strain response, or shear banding. Interestingly, this effect is independent of chain length over the range of parameters we have investigated so far, and we believe this is the first direct observation of shear banding in deformed polymer glasses under cylindrical confinement. Finally, by using the isoconfigurational ensemble approach, we provide evidence that the location where the shear band forms is due to structural features that are frozen in place during sample preparation.
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Affiliation(s)
- Amit Shavit
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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50
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Structure and properties of polyethylene-based and EVOH-based multilayered films with layer thicknesses of 150nm and greater. Eur Polym J 2015. [DOI: 10.1016/j.eurpolymj.2014.12.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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