1
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Yang Z, Xu X, Douglas JF, Xu WS. Confinement effect of inter-arm interactions on glass formation in star polymer melts. J Chem Phys 2024; 160:044503. [PMID: 38265089 DOI: 10.1063/5.0185412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/25/2023] [Indexed: 01/25/2024] Open
Abstract
We utilized molecular dynamic simulation to investigate the glass formation of star polymer melts in which the topological complexity is varied by altering the number of star arms (f). Emphasis was placed on how the "confinement effect" of repulsive inter-arm interactions within star polymers influences the thermodynamics and dynamics of star polymer melts. All the characteristic temperatures of glass formation were found to progressively increase with increasing f, but unexpectedly the fragility parameter KVFT was found to decrease with increasing f. As previously observed, stars having more than 5 or 6 arms adopt an average particle-like structure that is more contracted relative to the linear polymer size having the same mass and exhibit a strong tendency for intermolecular and intramolecular segregation. We systematically analyzed how varying f alters collective particle motion, dynamic heterogeneity, the decoupling exponent ζ phenomenologically linking the slow β- and α-relaxation times, and the thermodynamic scaling index γt. Consistent with our hypothesis that the segmental dynamics of many-arm star melts and thin supported polymer films should exhibit similar trends arising from the common feature of high local segmental confinement, we found that ζ increases considerably with increasing f, as found in supported polymer films with decreasing thickness. Furthermore, increasing f led to greatly enhanced elastic heterogeneity, and this phenomenon correlates strongly with changes in ζ and γt. Our observations should be helpful in building a more rational theoretical framework for understanding how molecular topology and geometrical confinement influence the dynamics of glass-forming materials more broadly.
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Affiliation(s)
- Zhenyue Yang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China
- Academy for Advanced Interdisciplinary Studies, Northeast Normal University, Changchun 130024, People's Republic of China
| | - Xiaolei Xu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Wen-Sheng Xu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China
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2
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Zhuravlyov V, Goree J, Elvati P, Violi A. Finite-size effects in the static structure factor S(k) and S(0) for a two-dimensional Yukawa liquid. Phys Rev E 2023; 108:035211. [PMID: 37849136 DOI: 10.1103/physreve.108.035211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 08/29/2023] [Indexed: 10/19/2023]
Abstract
Finite-size effects in the static structure factor S(k) are analyzed for an amorphous substance. As the number of particles is reduced, S(0) increases greatly, up to an order of magnitude. Meanwhile, there is a decrease in the height of the first peak S_{peak}. These finite-size effects are modeled accurately by the Binder formula for S(0) and our empirical formula for S_{peak}. Procedures are suggested to correct for finite-size effects in S(k) data and in the hyperuniformity index H≡S(0)/S_{peak}. These principles generally apply to S(k) obtained from particle positions in noncrystalline substances. The amorphous substance we simulate is a two-dimensional liquid, with a soft Yukawa interaction modeling a dusty plasma experiment.
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Affiliation(s)
- Vitaliy Zhuravlyov
- Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
| | - J Goree
- Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
| | - Paolo Elvati
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Angela Violi
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
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3
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Zhang H, Wang X, Zhang J, Yu HB, Douglas JF. Approach to hyperuniformity in a metallic glass-forming material exhibiting a fragile to strong glass transition. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2023; 46:50. [PMID: 37380868 DOI: 10.1140/epje/s10189-023-00308-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 06/05/2023] [Indexed: 06/30/2023]
Abstract
We investigate a metallic glass-forming (GF) material (Al90Sm10) exhibiting a fragile-strong (FS) glass-formation by molecular dynamics simulation to better understand this highly distinctive pattern of glass-formation in which many of the usual phenomenological relations describing relaxation times and diffusion of ordinary GF liquids no longer apply, and where instead genuine thermodynamic features are observed in response functions and little thermodynamic signature is exhibited at the glass transition temperature, Tg. Given the many unexpected similarities between the thermodynamics and dynamics of this metallic GF material with water, we first focus on the anomalous static scattering in this liquid, following recent studies on water, silicon and other FS GF liquids. We quantify the "hyperuniformity index" H of our liquid, which provides a quantitative measure of molecular "jamming". To gain insight into the T-dependence and magnitude of H, we also estimate another more familiar measure of particle localization, the Debye-Waller parameter 〈u2〉 describing the mean-square particle displacement on a timescale on the order of the fast relaxation time, and we also calculate H and 〈u2〉 for heated crystalline Cu. This comparative analysis between H and 〈u2〉 for crystalline and metallic glass materials allows us to understand the critical value of H on the order of 10-3 as being analogous to the Lindemann criterion for both the melting of crystals and the "softening" of glasses. We further interpret the emergence of FS GF and liquid-liquid phase separation in this class of liquids to arise from a cooperative self-assembly process in the GF liquid.
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Affiliation(s)
- Hao Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada.
| | - Xinyi Wang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada
| | - Jiarui Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada
| | - Hai-Bin Yu
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Jack F Douglas
- Material Measurement Laboratory, Material Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.
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4
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Tawade BV, Singh M, Apata IE, Veerasamy J, Pradhan N, Karim A, Douglas JF, Raghavan D. Polymer-Grafted Nanoparticles with Variable Grafting Densities for High Energy Density Polymeric Nanocomposite Dielectric Capacitors. JACS AU 2023; 3:1365-1375. [PMID: 37234129 PMCID: PMC10207098 DOI: 10.1021/jacsau.3c00022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 05/27/2023]
Abstract
Designing high energy density dielectric capacitors for advanced energy storage systems needs nanocomposite-based dielectric materials, which can utilize the properties of both inorganic and polymeric materials. Polymer-grafted nanoparticle (PGNP)-based nanocomposites alleviate the problems of poor nanocomposite properties by providing synergistic control over nanoparticle and polymer properties. Here, we synthesize "core-shell" barium titanate-poly(methyl methacrylate) (BaTiO3-PMMA) grafted PGNPs using surface-initiated atom transfer polymerization (SI-ATRP) with variable grafting densities of (0.303 to 0.929) chains/nm2 and high molecular masses (97700 g/mL to 130000 g/mol) and observe that low grafted density and high molecular mass based PGNP show high permittivity, high dielectric strength, and hence higher energy densities (≈ 5.2 J/cm3) as compared to the higher grafted density PGNPs, presumably due to their "star-polymer"-like conformations with higher chain-end densities that are known to enhance breakdown. Nonetheless, these energy densities are an order of magnitude higher than their nanocomposite blend counterparts. We expect that these PGNPs can be readily used as commercial dielectric capacitors, and these findings can serve as guiding principles for developing tunable high energy density energy storage devices using PGNP systems.
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Affiliation(s)
- Bhausaheb V. Tawade
- Department
of Chemistry, Howard University, Washington, D.C. 20059, United States
| | - Maninderjeet Singh
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
| | - Ikeoluwa E. Apata
- Department
of Chemistry, Howard University, Washington, D.C. 20059, United States
| | - Jagadesh Veerasamy
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
| | - Nihar Pradhan
- Department
of Chemistry, Physics and Atmospheric Science, Jackson State University, Jackson, Mississippi 39217, United States
| | - Alamgir Karim
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
| | - Jack F. Douglas
- Material
Science and Engineering Division, National
Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Dharmaraj Raghavan
- Department
of Chemistry, Howard University, Washington, D.C. 20059, United States
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5
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Zhuravlyov V, Goree J, Douglas JF, Elvati P, Violi A. Comparison of the static structure factor at long wavelengths for a dusty plasma liquid and other liquids. Phys Rev E 2022; 106:055212. [PMID: 36559416 DOI: 10.1103/physreve.106.055212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 10/23/2022] [Indexed: 06/17/2023]
Abstract
Especially small values of the static structure factor S(k) at long wavelengths, i.e., small k, were obtained in an analysis of experimental data, for a two-dimensional dusty plasma in its liquid state. For comparison, an analysis of S(k) data was carried out for many previously published experiments with other liquids. The latter analysis indicates that the magnitude of S(k) at small k is typically in a range 0.02-0.13. In contrast, the corresponding value for a dusty plasma liquid was found to be as small as 0.0139. Another basic finding for the dusty plasma liquid is that S(k) at small k generally increases with temperature, with its lowest value, noted above, occurring near the melting point. Simulations were carried out for the dusty plasma liquid, and their results are generally consistent with the experiment. Since a dusty plasma has a soft interparticle interaction, our findings support earlier theoretical suggestions that a useful design strategy for creating materials having exceptionally low values of S(0), so-called hyperuniform materials, is the use of a condensed material composed of particles that interact softly at their periphery.
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Affiliation(s)
- Vitaliy Zhuravlyov
- Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
| | - J Goree
- Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Paolo Elvati
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Angela Violi
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
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Wu W, Singh M, Zhai Y, Masud A, Tonny W, Yuan C, Yin R, Al-Enizi AM, Bockstaller MR, Matyjaszewski K, Douglas JF, Karim A. Facile Entropy-Driven Segregation of Imprinted Polymer-Grafted Nanoparticle Brush Blends by Solvent Vapor Annealing Soft Lithography. ACS APPLIED MATERIALS & INTERFACES 2022; 14:45765-45774. [PMID: 36174114 DOI: 10.1021/acsami.2c11134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Polymer-grafted nanoparticles (PGNPs) have attracted extensive research interest due to their potential for enhancing mechanical and electrical properties of both bulk polymer composite materials, as well as thin polymer films incorporating these nanoparticles (NPs). In previous studies, we have shown that an entropic driving force serves to organize low-molecular-mass PGNPs in imprinted blend films of PGNPs with low-molecular-mass homopolymers. In this work, we developed a novel solvent vapor annealing soft lithography (SVA-SL) method to overcome the technical difficulties in processing the high-molecular-mass PGNP blends due to the intrinsically sluggish melt annealing kinetics found in the phase separation of these blend PGNP materials. In particular, we utilized SVA-SL to create nanopatterns in blends of PGNPs having relatively high-molecular-mass-grafted layers but with cores of NPs having greatly different sizes. The minimization of the entropic free energy in the present system corresponded to larger PGNPs partitioning almost exclusively into the "mesa" regions of the imprinted PGNP blend films, as quantified by the estimation of the partition coefficient, Kp. The use of the SVA-SL processing method is important because it allows facile imprint patterning of PGNP materials and large-scale organization of the PGNPs even when the grafted chain lengths are long enough for the chains to be highly entangled, allowing enhanced thermo-mechanical property enhancements of the resulting films and a corresponding extended range of potential nanotech applications.
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Affiliation(s)
- Wenjie Wu
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas77204, United States
| | - Maninderjeet Singh
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas77204, United States
| | - Yue Zhai
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania15213, United States
| | - Ali Masud
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas77204, United States
| | - Wafa Tonny
- Department of Materials Science and Engineering, University of Houston, Houston, Texas77204, United States
| | - Chuqing Yuan
- Department of Materials Science and Engineering, University of Houston, Houston, Texas77204, United States
| | - Rongguan Yin
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania15213, United States
| | - Abdullah M Al-Enizi
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh11451, Saudi Arabia
| | - Michael R Bockstaller
- Department of Materials Science and Engineering, University of Houston, Houston, Texas77204, United States
| | - Krzysztof Matyjaszewski
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania15213, United States
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland20899, United States
| | - Alamgir Karim
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas77204, United States
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7
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Zheng X, Guo Y, Douglas JF, Xia W. Understanding the role of cross-link density in the segmental dynamics and elastic properties of cross-linked thermosets. J Chem Phys 2022; 157:064901. [PMID: 35963735 DOI: 10.1063/5.0099322] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cross-linking is known to play a pivotal role in the relaxation dynamics and mechanical properties of thermoset polymers, which are commonly used in structural applications because of their light weight and inherently strong nature. Here, we employ a coarse-grained (CG) polymer model to systematically explore the effect of cross-link density on basic thermodynamic properties as well as corresponding changes in the segmental dynamics and elastic properties of these network materials upon approaching their glass transition temperatures (Tg). Increasing the cross-link density unsurprisingly leads to a significant slowing down of the segmental dynamics, and the fragility K of glass formation shifts in lockstep with Tg, as often found in linear polymer melts when the polymer mass is varied. As a consequence, the segmental relaxation time τα becomes almost a universal function of reduced temperature, (T - Tg)/Tg, a phenomenon that underlies the applicability of the "universal" Williams-Landel-Ferry (WLF) relation to many polymer materials. We also test a mathematical model of the temperature dependence of the linear elastic moduli based on a simple rigidity percolation theory and quantify the fluctuations in the local stiffness of the network material. The moduli and distribution of the local stiffness likewise exhibit a universal scaling behavior for materials having different cross-link densities but fixed (T - Tg)/Tg. Evidently, Tg dominates both τα and the mechanical properties of our model cross-linked polymer materials. Our work provides physical insights into how the cross-link density affects glass formation, aiding in the design of cross-linked thermosets and other structurally complex glass-forming materials.
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Affiliation(s)
- Xiangrui Zheng
- Department of Mechanics, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Yafang Guo
- Department of Mechanics, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Wenjie Xia
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, North Dakota 58108, USA
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Xu X, Xu WS. Melt Properties and String Model Description of Glass Formation in Graft Polymers of Different Side-Chain Lengths. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Xiaolei Xu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Wen-Sheng Xu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
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9
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Wu W, Singh M, Masud A, Wang X, Nallapaneni A, Xiao Z, Zhai Y, Wang Z, Terlier T, Bleuel M, Yuan G, Satija SK, Douglas JF, Matyjaszewski K, Bockstaller MR, Karim A. Control of Phase Morphology of Binary Polymer Grafted Nanoparticle Blend Films via Direct Immersion Annealing. ACS NANO 2021; 15:12042-12056. [PMID: 34255492 DOI: 10.1021/acsnano.1c03357] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
While the phase separation of binary mixtures of chemically different polymer-grafted nanoparticles (PGNPs) is observed to superficially resemble conventional polymer blends, the presence of a "soft" polymer-grafted layer on the inorganic core of these nanoparticles qualitatively alters the phase separation kinetics of these "nanoblends" from the typical pattern of behavior seen in polymer blends and other simple fluids. We investigate this system using a direct immersion annealing method (DIA) that allows for a facile tuning of the PGNPs phase boundary, phase separation kinetics, and the ultimate scale of phase separation after a sufficient "aging" time. In particular, by switching the DIA solvent composition from a selective one (which increases the interaction parameter according to Timmerman's rule) to an overall good solvent for both PGNP components, we can achieve rapid switchability between phase-separated and homogeneous states. Despite a relatively low and non-classical power-law coarsening exponent, the overall phase separation process is completed on a time scale on the order of a few minutes. Moreover, the roughness of the PGNP blend film saturates at a scale that is proportional to the in-plane phase separation pattern scale, as observed in previous blend and block copolymer film studies. The relatively low magnitude of the coarsening exponent n is attributed to a suppression of hydrodynamic interactions between the PGNPs. The DIA method provides a significant opportunity to control the phase separation morphology of PGNP blends by solution processing, and this method is expected to be quite useful in creating advanced materials.
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Affiliation(s)
- Wenjie Wu
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
| | - Maninderjeet Singh
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
| | - Ali Masud
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
| | - Xiaoteng Wang
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
| | - Asritha Nallapaneni
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
| | - Zihan Xiao
- Department of Materials Science and Engineering, University of Houston, Houston, Texas 77204, United States
| | - Yue Zhai
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Zongyu Wang
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Tanguy Terlier
- SIMS Laboratory, Shared Equipment Authority, Rice University, Houston, Texas 77005, United States
| | - Markus Bleuel
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Guangcui Yuan
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Sushil K Satija
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Krzysztof Matyjaszewski
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Michael R Bockstaller
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Alamgir Karim
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
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Douglas JF, Xu WS. Equation of State and Entropy Theory Approach to Thermodynamic Scaling in Polymeric Glass-Forming Liquids. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00075] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Wen-Sheng Xu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
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