1
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Atiq O, Ricci E, Baschetti MG, De Angelis MG. Molecular Simulations of Hydrogen Sorption in Semicrystalline High-Density Polyethylene: The Impact of the Surface Fraction of Tie-Chains. J Phys Chem B 2024; 128:2799-2810. [PMID: 38452257 PMCID: PMC10961721 DOI: 10.1021/acs.jpcb.3c07705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 03/09/2024]
Abstract
The modeling of the barrier properties of semicrystalline polymers has gained interest following the possible application of such materials as protective liners for the safe supply of pressurized hydrogen. The mass transport in such systems is intimately related to the complex intercalation between the crystal and amorphous phases, which was approached in this work through an all-atom representation of high-density polyethylene structures with a tailored fraction of amorphous-crystalline connections (tie-chains). Simulations of the polymer pressure-volume-temperature data and hydrogen sorption were performed by means of molecular dynamics and the Widom test particle insertion method. The discretization of the simulation domains of the semicrystalline structures allowed us to obtain profiles of density, degree of order, and gas solubility. The results indicated that the gas sorption in the crystalline regions is negligible and that the confinement of the amorphous phase between crystals induces a significant increase in density and a drop in the sorption capacity, even in the absence of tie-chains. Adding ties between the crystal and the amorphous phase results in further densification, an increase of the lamella tilt angle, and a decrease in the degree of crystallinity and hydrogen sorption coefficient, in agreement with several literature references.
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Affiliation(s)
- Omar Atiq
- Department
of Civil, Chemical, Environmental and Material Engineering, (DICAM), Alma Mater Studiorum − Università di
Bologna, via Terracini 28, Bologna 40131, Italy
- DPI, P.O. Box 902, Eindhoven 5600 AX, The Netherlands
| | - Eleonora Ricci
- Institute
for Materials and Processes, School of Engineering, University of Edinburgh, Sanderson Building, Robert Stevenson Road, Scotland EH9 3FB, U.K.
- DPI, P.O. Box 902, Eindhoven 5600 AX, The Netherlands
| | - Marco Giacinti Baschetti
- Department
of Civil, Chemical, Environmental and Material Engineering, (DICAM), Alma Mater Studiorum − Università di
Bologna, via Terracini 28, Bologna 40131, Italy
- DPI, P.O. Box 902, Eindhoven 5600 AX, The Netherlands
| | - Maria Grazia De Angelis
- Institute
for Materials and Processes, School of Engineering, University of Edinburgh, Sanderson Building, Robert Stevenson Road, Scotland EH9 3FB, U.K.
- Department
of Civil, Chemical, Environmental and Material Engineering, (DICAM), Alma Mater Studiorum − Università di
Bologna, via Terracini 28, Bologna 40131, Italy
- DPI, P.O. Box 902, Eindhoven 5600 AX, The Netherlands
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2
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Hussain MA, Yamamoto T, Adil SF, Yao S. Preparation and Characterization of High-Density Polyethylene with Alternating Lamellar Stems Using Molecular Dynamics Simulations. Polymers (Basel) 2024; 16:304. [PMID: 38276712 PMCID: PMC10819154 DOI: 10.3390/polym16020304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 01/18/2024] [Accepted: 01/19/2024] [Indexed: 01/27/2024] Open
Abstract
Mechanical recycling is the most efficient way to reduce plastic pollution due to its ability to maintain the intrinsic properties of plastics as well as provide economic benefits involved in other types of recycling. On the other hand, molecular dynamics (MD) simulations provide key insights into structural deformation, lamellar crystalline axis (c-axis) orientations, and reorganization, which are essential for understanding plastic behavior during structural deformations. To simulate the influence of structural deformations in high-density polyethylene (HDPE) during mechanical recycling while paying attention to obtaining an alternate lamellar orientation, the authors examine a specific way of preparing stacked lamella-oriented HDPE united atom (UA) models, starting from a single 1000 UA (C1000) chain of crystalline conformations and then packing such chain conformations into 2-chain, 10-chain, 15-chain, and 20-chain semi-crystalline models. The 2-chain, 10-chain, and 15-chain models yielded HDPE microstructures with the desired alternating lamellar orientations and entangled amorphous segments. On the other hand, the 20-chain model displayed multi-nucleus crystal growth instead of the lamellar-stack orientation. Structural characterization using a one-dimensional density profile and local order parameter {P2(r)} analyses demonstrated lamellar-stack orientation formation. All semi-crystalline models displayed the total density (ρ) and degree of crystallinity (χ) range of 0.90-0.94 g/cm-3 and ≥42-45%, respectively. A notable stress yield (σ_yield) ≈ 100-120 MPa and a superior elongation at break (ε_break) ~250% was observed under uniaxial strain deformation along the lamellar-stack orientation. Similarly, during the MD simulations, the microstructure phase change represented the average number of entanglements per chain (). From the present study, it can be recommended that the 10-chain alternate lamellar-stack orientation model is the most reliable miniature model for HDPE that can mimic industrially relevant plastic behavior in various conditions.
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Affiliation(s)
| | - Takashi Yamamoto
- Graduate School of Science and Engineering, Yamaguchi University, Yamaguchi 753-8512, Japan
| | - Syed Farooq Adil
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia;
| | - Shigeru Yao
- Central Research Institute, Fukuoka University, Fukuoka 814-0180, Japan
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3
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Xu Q, Tang X, Zhang J, Hu Y, Ma T. Unraveling Tribochemistry and Self-Lubrication Mechanism of Polytetrafluoroethylene by Reactive Coarse-Grained Molecular Dynamics Simulations. ACS APPLIED MATERIALS & INTERFACES 2023; 15:45506-45515. [PMID: 37703837 DOI: 10.1021/acsami.3c10784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
Lubrication of polymeric materials generally involves processes of atomic-scale chemical bond forming/breaking at the interface and mesoscale chain reorientation, disentanglement, and so forth. However, it is difficult to describe the important aspects of tribochemical reactions by conventional coarse-grained molecular dynamics (CGMD) simulations. Here, reactive CGMD simulations were conducted based on the ReaxFF force field to study the tribochemical interactions between polytetrafluoroethylene (PTFE) and iron. The chemical bond forming/breaking between the molecular chain and countersurface was fitted through the bond dissociation energies of specific reaction sites from all-atom ReaxFF-MD simulations. This enabled a quantitative description of tribochemical reactions in a macromolecule system. First, the number of anchoring bonds between PTFE molecules and the countersurface showed a strong correlation with the friction coefficient. The shearing process induced breaking of the interfacial anchoring bonds as well as chain disentanglement in the matrix, which consequently led to ordering reorientation of molecular chains toward sliding direction and hence decrease of friction. Second, two competitive factors were clarified to affect polymer friction with varying temperatures. The decrease of interfacial anchoring reactivity and molecular chain mobility at low temperature prohibited reorientation of molecular chains and increased the friction coefficient. On the other hand, the hardening of PTFE and the reduction in effective contact area at low temperatures decreased the friction coefficient. This led to a turning point with a maximum friction coefficient around 100 K. These results shed light on the essential role of tribochemical reactions on polymer lubrication, especially under low temperatures, which provides design guidance of polymeric lubrication systems for engineering applications.
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Affiliation(s)
- Qiang Xu
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
- Computational Aerodynamics Institute, China Aerodynamics Research and Development Center, Mianyang 621000, Sichuan, China
| | - Xin Tang
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
| | - Jie Zhang
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yuanzhong Hu
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
| | - Tianbao Ma
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China
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4
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Zhang W, Zou L. Mismatch in Nematic Interactions Leads to Composition-Dependent Crystal Nucleation in Polymer Blends. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c02378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Affiliation(s)
- Wenlin Zhang
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Lingyi Zou
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
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5
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Vao-soongnern V, Sukhonthamethirat N, Rueangsri K, Sirirak K, Matsuba G. Molecular simulation of the structural formation of mono- and bidisperse polyethylene upon cooling from the melts. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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6
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Gedde U, Unge M, Nilsson F, Hedenqvist M. Mass and charge transport in polyethylene – Structure, morphology and properties. POLYMER 2023. [DOI: 10.1016/j.polymer.2022.125617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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7
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Cooling-Rate Computer Simulations for the Description of Crystallization of Organic Phase-Change Materials. Int J Mol Sci 2022; 23:ijms232314576. [PMID: 36498903 PMCID: PMC9737975 DOI: 10.3390/ijms232314576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 11/17/2022] [Accepted: 11/20/2022] [Indexed: 11/24/2022] Open
Abstract
A molecular-level insight into phase transformations is in great demand for many molecular systems. It can be gained through computer simulations in which cooling is applied to a system at a constant rate. However, the impact of the cooling rate on the crystallization process is largely unknown. To this end, here we performed atomic-scale molecular dynamics simulations of organic phase-change materials (paraffins), in which the cooling rate was varied over four orders of magnitude. Our computational results clearly show that a certain threshold (1.2 × 1011 K/min) in the values of cooling rates exists. When cooling is slower than the threshold, the simulations qualitatively reproduce an experimentally observed abrupt change in the temperature dependence of the density, enthalpy, and thermal conductivity of paraffins upon crystallization. Beyond this threshold, when cooling is too fast, the paraffin's properties in simulations start to deviate considerably from experimental data: the faster the cooling, the larger part of the system is trapped in the supercooled liquid state. Thus, a proper choice of a cooling rate is of tremendous importance in computer simulations of organic phase-change materials, which are of great promise for use in domestic heat storage devices.
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De Nicola A, Touloupidis V, Kanellopoulos V, Albunia AR, Milano G. A combined experimental and molecular simulation study on stress generation phenomena during the Ziegler-Natta polyethylene catalyst fragmentation process. NANOSCALE ADVANCES 2022; 4:5178-5188. [PMID: 36504732 PMCID: PMC9680958 DOI: 10.1039/d2na00406b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 10/14/2022] [Indexed: 06/17/2023]
Abstract
The morphology of particles obtained under different pre-polymerization conditions has been connected to the stress generation mechanism at the polymer/catalyst interface. A combination of experimental characterization techniques and atomistic molecular dynamics simulations allowed a systematic investigation of experimental conditions leading to a certain particle morphology, and hence to a final polymer with specific features. Atomistic models of nascent polymer phases in contact with magnesium dichloride surfaces have been developed and validated. Using these detailed models, in the framework of McKenna's hypothesis, the pressure increase due to the polymerization reaction has been calculated under different conditions and is in good agreement with experimental scenarios. This molecular scale knowledge and the proposed investigation strategy would allow the pre-polymerization conditions to be better defined and the properties of the nascent polymer to be tuned, ensuring proper operability along the whole polymer production process.
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Affiliation(s)
- Antonio De Nicola
- Scuola Superiore Meridionale Largo San Marcellino 10 80132 Napoli Italy
| | - Vasileios Touloupidis
- Innovation & Technology, Borealis Polyolefine GmbH St. Peter Strasse 25 4021 Linz Austria
| | | | - Alexandra R Albunia
- Innovation & Technology, Borealis Polyolefine GmbH St. Peter Strasse 25 4021 Linz Austria
| | - Giuseppe Milano
- Dipartimento di Ingegneria Chimica dei Materiali e della Produzione Industriale, Università degli Studi di Napoli Federico II Piazzale V. Tecchio 80 80125 Napoli Italy
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9
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Interfacial Forces in Free-Standing Layers of Melted Polyethylene, from Critical to Nanoscopic Thicknesses. Polymers (Basel) 2022; 14:polym14183865. [PMID: 36146008 PMCID: PMC9503058 DOI: 10.3390/polym14183865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/04/2022] [Accepted: 09/07/2022] [Indexed: 11/17/2022] Open
Abstract
Molecular dynamics simulations of ultrathin free-standing layers made of melted (373.15–673.15 K) polyethylene chains, which exhibit a lower melting temperature (compared to the bulk value), were carried out to investigate the dominant pressure forces that shape the conformation of chains at the interfacial and bulk liquid regions. We investigated layer thicknesses, tL, from the critical limit of mechanical stability up to lengths of tens of nm and found a normal distribution of bonds dominated by slightly stretched chains across the entire layer, even at large temperatures. In the bulk region, the contribution of bond vibrations to pressure was one order of magnitude larger than the contributions from interchain interactions, which changed from cohesive to noncohesive at larger temperatures just at a transition temperature that was found to be close to the experimentally derived onset temperature for thermal stability. The interchain interactions produced noncohesive interfacial regions at all temperatures in both directions (normal and lateral to the surface layer). Predictions for the value of the surface tension, γ, were consistent with experimental results and were independent of tL. However, the real interfacial thickness—measured from the outermost part of the interface up to the point where γ reached its maximum value—was found to be dependent on tL, located at a distance of 62 Å from the Gibbs dividing surface in the largest layer studied (1568 chains or 313,600 bins); this was ~4 times the length of the interfacial thickness measured in the density profiles.
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10
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Mosoabisane MFT, Luyt AS, van Sittert CGCE. Comparative experimental and modelling study of the thermal and thermo-mechanical properties of LLDPE/wax blends. JOURNAL OF POLYMER RESEARCH 2022. [DOI: 10.1007/s10965-022-03136-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
AbstractThe interactions and morphology of molecules in a polymer blend influence the physical properties of the blend. However, little is known about the influence of molecular interaction and morphology on the thermal and mechanical properties of LLDPE/wax blends. Although cooling rate can be used to investigate blends' thermal and mechanical properties, it is inadequate to determine interactions between the molecules in the LLDPE/wax blends. However, since the morphology is related to the thermal and mechanical properties of polymer blends and could be related to the cooling rate, LLDPE/wax samples prepared by melt mixing were cooled at different rates. The thermal and mechanical properties of the LLDPE/wax blends were modelled through molecular dynamic simulations. The modelled transitions were compared to experimentally determined mechanical relaxations of LLDPE/wax blends to investigate the effect of wax addition on the blend crystallinity. The crystallization behaviour of the blends was studied by differential scanning calorimetry, dynamic mechanical behaviour by dynamic mechanical analysis, and differences in crystallinity by X-ray diffraction. There were no significant differences between the results for the slow- and quench-cooled samples, confirming the rapid crystallization of both the LLDPE and the wax. Experiments and molecular dynamics simulations confirmed the cocrystallization of wax with LLDPE.
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11
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Zou L, Zhang W. Molecular Dynamics Simulations of the Effects of Entanglement on Polymer Crystal Nucleation. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00817] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lingyi Zou
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Wenlin Zhang
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
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12
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Yamamoto T. Chiral selecting crystallization of helical polymers: A molecular dynamics simulation for the POM-like bare helix. J Chem Phys 2022; 157:014901. [DOI: 10.1063/5.0097112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Polymer crystallization has long been a fascinating problem and is still attracting many researchers. Most of the previous simulations are concentrated on clarifying the universal aspects of polymer crystallization using model linear polymers such as polyethylene. We are recently focusing on a nearly untouched but very interesting problem of chiral selecting crystallization in helical polymers. We previously proposed a stepwise approach using two kinds of helical polymers, simple "bare" helical polymers made of backbone atoms only such as polyoxymethylene (POM) and "general" helical polymers containing complicated side groups such as isotactic polypropylene (iPP). We have already reported on the crystallization in oligomeric POM-like helix but have observed only weak chiral selectivity during crystallization. In the present paper, we investigate the crystallization of sufficiently long POM-like polymer both from the isotropic melt and from the highly stretched melt. We find in both cases that the polymer shows a clear chiral selecting crystallization. Especially the observation of a single crystal growing from the isotropic melt is very illuminating. It shows that the crystal thickness and the crystal chirality is closely correlated; thicker crystals show definite chirality while thinner ones are mostly mixtures of the R- and the L- handed stems. The single crystal is found to have a marked lenticular shape, where the thinner growth front, since being made of the mixture, shows no chiral selectivity. Final chiral crystal is found to be completed through helix reversal processes within thicker regions.
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Affiliation(s)
- Takashi Yamamoto
- Department of Physics and Informatics, Yamaguchi University, Japan
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13
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Sheng J, Chen W, Cui K, Li L. Polymer crystallization under external flow. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:036601. [PMID: 35060493 DOI: 10.1088/1361-6633/ac4d92] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
The general aspects of polymer crystallization under external flow, i.e., flow-induced crystallization (FIC) from fundamental theoretical background to multi-scale characterization and modeling results are presented. FIC is crucial for modern polymer processing, such as blowing, casting, and injection modeling, as two-third of daily-used polymers is crystalline, and nearly all of them need to be processed before final applications. For academics, the FIC is intrinsically far from equilibrium, where the polymer crystallization behavior is different from that in quiescent conditions. The continuous investigation of crystallization contributes to a better understanding on the general non-equilibrium ordering in condensed physics. In the current review, the general theories related to polymer nucleation under flow (FIN) were summarized first as a preliminary knowledge. Various theories and models, i.e., coil-stretch transition and entropy reduction model, are briefly presented together with the modified versions. Subsequently, the multi-step ordering process of FIC is discussed in detail, including chain extension, conformational ordering, density fluctuation, and final perfection of the polymer crystalline. These achievements for a thorough understanding of the fundamental basis of FIC benefit from the development of various hyphenated rheometer, i.e., rheo-optical spectroscopy, rheo-IR, and rheo-x-ray scattering. The selected experimental results are introduced to present efforts on elucidating the multi-step and hierarchical structure transition during FIC. Then, the multi-scale modeling methods are summarized, including micro/meso scale simulation and macroscopic continuum modeling. At last, we briefly describe our personal opinions related to the future directions of this field, aiming to ultimately establish the unified theory of FIC and promote building of the more applicable models in the polymer processing.
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Affiliation(s)
- Junfang Sheng
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Wei Chen
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Kunpeng Cui
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Liangbin Li
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, People's Republic of China
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14
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Precursor formation and crystal nucleation in stretched polyethylene/carbon nanotube nanocomposites. POLYMER 2022. [DOI: 10.1016/j.polymer.2021.124438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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15
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González-Mijangos JA, Lima E, Guerra-González R, Ramírez-Zavaleta FI, Rivera JL. Critical Thickness of Free-Standing Nanothin Films Made of Melted Polyethylene Chains via Molecular Dynamics. Polymers (Basel) 2021; 13:3515. [PMID: 34685274 PMCID: PMC8538407 DOI: 10.3390/polym13203515] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/04/2021] [Accepted: 10/07/2021] [Indexed: 01/16/2023] Open
Abstract
The mechanical stability of nanothin free-standing films made of melted polyethylene chains was predicted via molecular dynamics simulations in the range of 373.15-673.15 K. The predicted critical thickness, tc, increased with the square of the temperature, T, with additional chains needed as T increased. From T = 373.15 K up to the thermal limit of stability for polyethylene, tc values were in the range of nanothin thicknesses (3.42-5.63 nm), which approximately corresponds to 44-55 chains per 100 nm2. The density at the center of the layer and the interfacial properties studied (density profiles, interfacial thickness, and radius of gyration) showed independence from the film thickness at the same T. The polyethylene layer at its tc showed a lower melting T (<373.15 K) than bulk polyethylene.
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Affiliation(s)
- José Antonio González-Mijangos
- Facultad de Ciencias Físico-Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58000, Mexico; (J.A.G.-M.); (F.I.R.-Z.)
| | - Enrique Lima
- Laboratorio de Fisicoquímica y Reactividad de Superficies (LaFReS), Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de Mexico, Circuito Exterior S/N, CU, Del. Coyoacán, Ciudad de Mexico 04510, Mexico;
| | - Roberto Guerra-González
- Facultad de Ingeniería Química, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58000, Mexico;
| | - Fernando Iguazú Ramírez-Zavaleta
- Facultad de Ciencias Físico-Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58000, Mexico; (J.A.G.-M.); (F.I.R.-Z.)
| | - José Luis Rivera
- Facultad de Ciencias Físico-Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58000, Mexico; (J.A.G.-M.); (F.I.R.-Z.)
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16
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A computer simulation of the effect of temperature on melt chain dimensions of random short chain branched polyethylene. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.123772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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17
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Zhang W, Zou L. Molecular Dynamics Simulations of Crystal Nucleation near Interfaces in Incompatible Polymer Blends. Polymers (Basel) 2021; 13:347. [PMID: 33499036 PMCID: PMC7865509 DOI: 10.3390/polym13030347] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/17/2021] [Accepted: 01/19/2021] [Indexed: 11/17/2022] Open
Abstract
We apply molecular dynamics (MD) simulations to investigate crystal nucleation in incompatible polymer blends under deep supercooling conditions. Simulations of isothermal nucleation are performed for phase-separated blends with different degrees of incompatibility. In weakly segregated blends, slow and incompatible chains in crystallizable polymer domains can significantly hinder the crystal nucleation and growth. When a crystallizable polymer is blended with a more mobile species in interfacial regions, enhanced molecular mobility leads to the fast growth of crystalline order. However, the incubation time remains the same as that in pure samples. By inducing anisotropic alignment near the interfaces of strongly segregated blends, phase separation also promotes crystalline order to grow near interfaces between different polymer domains.
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Affiliation(s)
- Wenlin Zhang
- Department of Chemistry, Dartmouth College, Hanover, NH 03755, USA;
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18
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Affiliation(s)
- Wenlin Zhang
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Ronald G. Larson
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
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19
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Chen W, Ren Y. Molecular dynamics simulations of polymerisation and crystallisation at constant chemical potential. MOLECULAR SIMULATION 2020. [DOI: 10.1080/08927022.2020.1776276] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Wei Chen
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Ying Ren
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, People's Republic of China
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20
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Ranganathan R, Kumar V, Brayton AL, Kröger M, Rutledge GC. Atomistic Modeling of Plastic Deformation in Semicrystalline Polyethylene: Role of Interphase Topology, Entanglements, and Chain Dynamics. Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b02308] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Raghavan Ranganathan
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- Materials Science and Engineering, Indian Institute of Technology Gandhinagar, Gujarat 382355, India
| | - Vaibhaw Kumar
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Alexander L. Brayton
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Martin Kröger
- Polymer Physics, Department of Materials, ETH Zurich, Zurich 8093, Switzerland
| | - Gregory C. Rutledge
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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21
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Nicholson DA, Rutledge GC. Flow-induced inhomogeneity and enhanced nucleation in a long alkane melt. POLYMER 2020. [DOI: 10.1016/j.polymer.2020.122605] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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22
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McKechnie D, Cree J, Wadkin-Snaith D, Johnston K. Glass transition temperature of a polymer thin film: Statistical and fitting uncertainties. POLYMER 2020. [DOI: 10.1016/j.polymer.2020.122433] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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23
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Nieto Simavilla D, Sgouros AP, Vogiatzis GG, Tzoumanekas C, Georgilas V, Verbeeten WMH, Theodorou DN. Molecular Dynamics Test of the Stress-Thermal Rule in Polyethylene and Polystyrene Entangled Melts. Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b02088] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- David Nieto Simavilla
- Universidad de Burgos, Burgos 09006, Spain
- Basque Center for Applied Mathematics, Bilbao 48009, Spain
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24
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Rissanou AN, Bačová P, Harmandaris V. Investigation of the properties of nanographene in polymer nanocomposites through molecular simulations: dynamics and anisotropic Brownian motion. Phys Chem Chem Phys 2019; 21:23843-23854. [PMID: 31369014 DOI: 10.1039/c9cp02074h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The dynamical behavior of nanographene sheets dispersed in polymer matrices is investigated through united-atom molecular dynamics simulations. The Brownian motion of the sheet and the anisotropy in its translational and orientational diffusion are the topics of the current study. Different polymer matrices and pristine and functionalized graphene constitute various nanocomposite systems. Interactions between the nanographene flake and the matrix determine the dynamics of the systems. The dynamics is reduced in polyethylene oxide compared to polyethylene matrix, whereas carboxylated sheets move considerably slower than the pristine nanographene in any matrix. Diffusion is anisotropic for short times, while it becomes isotropic in the long time limit. The in-plane motion of the nanographene sheet is faster than the out-of-plane component, in agreement with the diffusion of perfectly oblate ellipsoids. In functionalized graphene, the anisotropy is suppressed. By exploring the temperature effect on both the nanographene sheet and polymer close to the surface, indications for coupling in the motion of the two components are revealed. The strong effect of edge functional groups on the dynamics can be used as a way to control the Brownian motion of nanographene sheets in polymer nanocomposites and consequently tailor the properties of the materials.
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Affiliation(s)
- Anastassia N Rissanou
- Institute of Applied and Computational Mathematics (IACM), Foundation for Research and Technology Hellas (FORTH), GR-71110 Heraklion, Greece.
| | - Petra Bačová
- Institute of Applied and Computational Mathematics (IACM), Foundation for Research and Technology Hellas (FORTH), GR-71110 Heraklion, Greece.
| | - Vagelis Harmandaris
- Institute of Applied and Computational Mathematics (IACM), Foundation for Research and Technology Hellas (FORTH), GR-71110 Heraklion, Greece. and Department of Mathematics and Applied Mathematics, University of Crete, GR-71409, Heraklion, Crete, Greece.
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25
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Uncertainty Quantification for Mechanical Properties of Polyethylene Based on Fully Atomistic Model. MATERIALS 2019; 12:ma12213613. [PMID: 31689882 PMCID: PMC6862252 DOI: 10.3390/ma12213613] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/12/2019] [Accepted: 10/25/2019] [Indexed: 12/04/2022]
Abstract
This study is to assess the effect of temperature and strain rate on the mechanical properties of amorphous polyethylene (PE) based on fully atomistic model. A stochastic constitutive model using data obtained from molecular dynamics (MD) simulations for the material is constructed. Subsequently, a global sensitivity analysis approach is then employed to predict the essential parameters of the mechanical model. The sensitivity indices show that the key parameter affecting Young’s modulus and yield stress is the temperature followed by the strain rate.
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26
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Single-chain folding of a quenched isotactic polypropylene chain through united atom molecular dynamics simulations. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.121861] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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27
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Zhai Z, Fusco C, Morthomas J, Perez M, Lame O. Disentangling and Lamellar Thickening of Linear Polymers during Crystallization: Simulation of Bimodal and Unimodal Molecular Weight Distribution Systems. ACS NANO 2019; 13:11310-11319. [PMID: 31593434 DOI: 10.1021/acsnano.9b04459] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We have performed coarse-grained molecular dynamics simulations to study the isothermal crystallization of bimodal and unimodal molecular weight distribution (MWD) polymers with equivalent average molecular weight (Mw). By using primitive path analysis, we can monitor the entanglement evolution during the process of crystallization. We have discovered a quantitative correlation between the degree of disentanglement and crystallinity, indicating that chain disentanglement permits the process of crystallization. In addition, the crystalline stem length also displays a linear relation with the degree of disentanglement at different temperatures. Based on the observation in our simulations, we can build a scenario of the whole process of chain disentangling and lamellar thickening on the basis of chain sliding diffusion. Furthermore, we have enough evidence to infer that the temperature dependence of crystalline stem length is basically a result of temperature dependence of chain sliding diffusion. Our observations are also in agreement with Hikosaka's sliding diffusion theory. Compared to the unimodal system, the disentanglement degree of the bimodal system is more delayed than its crystallinity due to the slower chain sliding of the long-chain component; the bimodal system reaches a larger crystalline stem length at all temperatures due to the promotion of higher chain sliding mobility of the short-chain component.
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Affiliation(s)
- Zengqiang Zhai
- Univ de Lyon, INSA Lyon , MATEIS, UMR CNRS 5510, 69621 Villeurbanne , France
| | - Claudio Fusco
- Univ de Lyon, INSA Lyon , MATEIS, UMR CNRS 5510, 69621 Villeurbanne , France
| | - Julien Morthomas
- Univ de Lyon, INSA Lyon , MATEIS, UMR CNRS 5510, 69621 Villeurbanne , France
| | - Michel Perez
- Univ de Lyon, INSA Lyon , MATEIS, UMR CNRS 5510, 69621 Villeurbanne , France
| | - Olivier Lame
- Univ de Lyon, INSA Lyon , MATEIS, UMR CNRS 5510, 69621 Villeurbanne , France
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28
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Gao R, Zhao L, Shao Y, Liu Z, He X, Liu B. Molecular dynamics study of polyethylene chain non-isothermal crystallisation: effects of chain length and branch structure. MOLECULAR SIMULATION 2019. [DOI: 10.1080/08927022.2019.1587759] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Rui Gao
- Shanghai Key Laboratory of Multiphase Material Chemical Engineering, East China University of Science and Technology, Shanghai, People’s Republic of China
| | - Li Zhao
- Shanghai Key Laboratory of Multiphase Material Chemical Engineering, East China University of Science and Technology, Shanghai, People’s Republic of China
| | - Yunqi Shao
- Shanghai Key Laboratory of Multiphase Material Chemical Engineering, East China University of Science and Technology, Shanghai, People’s Republic of China
| | - Zhen Liu
- Shanghai Key Laboratory of Multiphase Material Chemical Engineering, East China University of Science and Technology, Shanghai, People’s Republic of China
| | - Xuelian He
- Shanghai Key Laboratory of Multiphase Material Chemical Engineering, East China University of Science and Technology, Shanghai, People’s Republic of China
| | - Boping Liu
- College of Materials and Energy, South China Agricultural University, Guangzhou, People’s Republic of China
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29
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Zhang W, Larson RG. A metastable nematic precursor accelerates polyethylene oligomer crystallization as determined by atomistic simulations and self-consistent field theory. J Chem Phys 2019; 150:244903. [PMID: 31255080 DOI: 10.1063/1.5110681] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Using PYS, TraPPE, OPLS-L, and Flexible-Williams (FW) force field models, atomistic simulations at temperatures ranging from 450 K to 600 K are performed to predict the melt density ρ, the persistence length Np, the nematic coupling constant α, and crystallization dynamics for pentacontane (C50). The coupling constant α arises from packing entropy of rodlike Kuhn segments and increases with increasing ρ and Np. Together with a self-consistent field theory, Np and α are then used to predict the isotropic-to-nematic (IN) transition temperature for polyethylene (PE) oligomers as a function of chain length. The nematic phase is found to be metastable since the IN transition temperature lies below the crystal melting temperatures for C50 in simulations using different force fields. Finally, isothermal simulations of crystallization for PE C50 oligomers and C1000 polymers show that crystal nucleation may be much accelerated by quenching below the IN transition temperature, where chains in the isotropic state first rapidly form nematic ordered domains, within which crystalline order then grows. We also find that the PYS, TraPPE, and FW models overpredict the melting temperature for C50 by around 50 K, while the most flexible OPLS-L model gives a melting temperature within around 10 K of the experimental value. Although giving a more accurate melting temperature, the slow crystallization kinetics of the OPLS-L model may limit its application in direct simulations of PE crystallization.
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Affiliation(s)
- Wenlin Zhang
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Ronald G Larson
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
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30
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Hall KW, Sirk TW, Klein ML, Shinoda W. A coarse-grain model for entangled polyethylene melts and polyethylene crystallization. J Chem Phys 2019; 150:244901. [PMID: 31255065 DOI: 10.1063/1.5092229] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The Shinoda-DeVane-Klein (SDK) model is herein demonstrated to be a viable coarse-grain model for performing molecular simulations of polyethylene (PE), affording new opportunities to advance molecular-level, scientific understanding of PE materials and processes. Both structural and dynamical properties of entangled PE melts are captured by the SDK model, which also recovers important aspects of PE crystallization phenomenology. Importantly, the SDK model can be used to represent a variety of materials beyond PE and has a simple functional form, making it unique among coarse-grain PE models. This study expands the suite of tools for studying PE in silico and paves the way for future work probing PE and PE-based composites at the molecular level.
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Affiliation(s)
- Kyle Wm Hall
- Department of Materials Chemistry, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
| | - Timothy W Sirk
- U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005, USA
| | - Michael L Klein
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - Wataru Shinoda
- Department of Materials Chemistry, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
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31
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Paajanen A, Vaari J, Verho T. Crystallization of cross-linked polyethylene by molecular dynamics simulation. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.03.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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32
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Hung JH, Patra TK, Meenakshisundaram V, Mangalara JH, Simmons DS. Universal localization transition accompanying glass formation: insights from efficient molecular dynamics simulations of diverse supercooled liquids. SOFT MATTER 2019; 15:1223-1242. [PMID: 30556082 DOI: 10.1039/c8sm02051e] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The origin of the precipitous dynamic arrest known as the glass transition is a grand open question of soft condensed matter physics. It has long been suspected that this transition is driven by an onset of particle localization and associated emergence of a glassy modulus. However, progress towards an accepted understanding of glass formation has been impeded by an inability to obtain data sufficient in chemical diversity, relaxation timescales, and spatial and temporal resolution to validate or falsify proposed theories for its physics. Here we first describe a strategy enabling facile high-throughput simulation of glass-forming liquids to nearly unprecedented relaxation times. We then perform simulations of 51 glass-forming liquids, spanning polymers, small organic molecules, inorganics, and metallic glass-formers, with longest relaxation times exceeding one microsecond. Results identify a universal particle-localization transition accompanying glass formation across all classes of glass-forming liquid. The onset temperature of non-Arrhenius dynamics is found to serve as a normalizing condition leading to a master collapse of localization data. This transition exhibits a non-universal relationship with dynamic arrest, suggesting that the nonuniversality of supercooled liquid dynamics enters via the dependence of relaxation times on local cage scale. These results suggest that a universal particle-localization transition may underpin the glass transition, and they emphasize the potential for recent theoretical developments connecting relaxation to localization and emergent elasticity to finally explain the origin of this phenomenon. More broadly, the capacity for high-throughput prediction of glass formation behavior may open the door to computational inverse design of glass-forming materials.
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Affiliation(s)
- Jui-Hsiang Hung
- Department of Polymer of Engineering, University of Akron, 250 South Forge St., Akron, OH 44325, USA
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33
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Walker CC, Genzer J, Santiso EE. Development of a fused-sphere SAFT-γ Mie force field for poly(vinyl alcohol) and poly(ethylene). J Chem Phys 2019; 150:034901. [DOI: 10.1063/1.5078742] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Christopher C. Walker
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Jan Genzer
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Erik E. Santiso
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
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34
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Moyassari A, Gkourmpis T, Hedenqvist MS, Gedde UW. Molecular Dynamics Simulations of Short-Chain Branched Bimodal Polyethylene: Topological Characteristics and Mechanical Behavior. Macromolecules 2019. [DOI: 10.1021/acs.macromol.8b01874] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ali Moyassari
- Fibre and Polymer Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Thomas Gkourmpis
- Innovation & Technology, Borealis AB, SE-444 86 Stenungsund, Sweden
| | - Mikael S. Hedenqvist
- Fibre and Polymer Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Ulf W. Gedde
- Fibre and Polymer Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
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35
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Molecular dynamics simulation of linear polyethylene blends: Effect of molar mass bimodality on topological characteristics and mechanical behavior. POLYMER 2019. [DOI: 10.1016/j.polymer.2018.12.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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36
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Glova AD, Volgin IV, Nazarychev VM, Larin SV, Lyulin SV, Gurtovenko AA. Toward realistic computer modeling of paraffin-based composite materials: critical assessment of atomic-scale models of paraffins. RSC Adv 2019; 9:38834-38847. [PMID: 35540183 PMCID: PMC9076000 DOI: 10.1039/c9ra07325f] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 08/24/2020] [Accepted: 11/19/2019] [Indexed: 11/30/2022] Open
Abstract
Paraffin-based composites represent a promising class of materials with numerous practical applications such as e.g. heat storage. Computer modeling of these complex multicomponent systems requires a proper theoretical description of both the n-alkane matrix and the non-alkane filler molecules. The latter can be modeled with the use of a state-of-the-art general-purpose force field such as GAFF, CHARMM, OPLS-AA and GROMOS, while the paraffin matrix is traditionally described in the frame of relatively old, alkane-specific force fields (TraPPE, NERD, and PYS). In this paper we link these two types of models and evaluate the performance of several general-purpose force fields in computer modeling of paraffin by their systematic comparison with earlier alkane-specific models as well as with experimental data. To this end, we have performed molecular dynamics simulations of n-eicosane bulk samples with the use of 10 different force fields: TraPPE, NERD, PYS, OPLS-UA, GROMOS, GAFF, GAFF2, OPLS-AA, L-OPLS-AA, and CHARMM36. For each force field we calculated several thermal, structural and dynamic characteristics of n-eicosane over a wide temperature range. Overall, our findings show that the general-purpose force fields such as CHARMM36, L-OPLS-AA and GAFF/GAFF2 are able to provide a realistic description of n-eicosane samples. While alkane-specific models outperform most general-purpose force fields as far as the temperature dependence of mass density, the coefficient of volumetric thermal expansion in the liquid state, and the crystallization temperature are concerned, L-OPLS-AA, CHARMM36 and GAFF2 force fields provide a better match with experiment for the shear viscosity and the diffusion coefficient in melt. Furthermore, we show that most general-purpose force fields are able to reproduce qualitatively the experimental triclinic crystal structure of n-eicosane at low temperatures. Atomic-scale computational models of paraffins are critically assessed and compared.![]()
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Affiliation(s)
- Artyom D. Glova
- Institute of Macromolecular Compounds
- Russian Academy of Sciences
- St. Petersburg
- Russia
| | - Igor V. Volgin
- Institute of Macromolecular Compounds
- Russian Academy of Sciences
- St. Petersburg
- Russia
| | - Victor M. Nazarychev
- Institute of Macromolecular Compounds
- Russian Academy of Sciences
- St. Petersburg
- Russia
| | - Sergey V. Larin
- Institute of Macromolecular Compounds
- Russian Academy of Sciences
- St. Petersburg
- Russia
| | - Sergey V. Lyulin
- Institute of Macromolecular Compounds
- Russian Academy of Sciences
- St. Petersburg
- Russia
- Faculty of Physics
| | - Andrey A. Gurtovenko
- Institute of Macromolecular Compounds
- Russian Academy of Sciences
- St. Petersburg
- Russia
- Faculty of Physics
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37
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Sato M, Kumada A, Hidaka K. Multiscale modeling of charge transfer in polymers with flexible backbones. Phys Chem Chem Phys 2019; 21:1812-1819. [DOI: 10.1039/c8cp05558k] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In order to evaluate carrier transfer properties in polymers with flexible backbones, we have proposed a simplified multi-scale modeling approach combining molecular dynamics simulations, first-principles calculations and kinetic Monte Carlo simulations.
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Affiliation(s)
- Masahiro Sato
- Research Center for Advanced Science and Technology
- The University of Tokyo
- Tokyo 153-0032
- Japan
| | - Akiko Kumada
- Department of Electrical Engineering and Information Systems
- The University of Tokyo
- Tokyo 113-8656
- Japan
| | - Kunihiko Hidaka
- Department of Electrical Engineering and Information Systems
- The University of Tokyo
- Tokyo 113-8656
- Japan
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38
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Casalegno M, Nicolini T, Famulari A, Raos G, Po R, Meille SV. Atomistic modelling of entropy driven phase transitions between different crystal modifications in polymers: the case of poly(3-alkylthiophenes). Phys Chem Chem Phys 2018; 20:28984-28989. [PMID: 30457608 DOI: 10.1039/c8cp05820b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Polymorphism and related solid-state phase transitions affect the structure and morphology and hence the properties of materials, but they are not-so-well understood. Atomistic computational methods can provide molecular-level insights, but they have rarely proven successful for transitions between polymorphic forms of crystalline polymers. In this work, we report atomistic molecular dynamics (MD) simulations of poly(3-alkylthiophenes) (P3ATs), widely used organic semiconductors to explore the experimentally observed, entropy-driven transition from form II to more common form I type polymorphs, or, more precisely, to form I mesophases. The transition is followed continuously, also considering X-ray diffraction evidence, for poly(3-hexylthiophene) (P3HT) and poly(3-butylthiophene) (P3BT), evidencing three main steps: (i) loss of side chain interdigitation, (ii) partial disruption of the original stacking order and (iii) reorganization of polymer chains into new, tighter, main-chain stacks and new layers with characteristic form I periodicities, substantially larger than those in the original form II. The described approach, likely applicable to other important transitions in polymers, provides previously inaccessible insight into the structural organization and disorder features of form I structures of P3ATs, not only in their development from form II structures but also from melts or solutions.
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Affiliation(s)
- Mosè Casalegno
- Dipartimento di Chimica, Materiali e Ingegneria Chimica "G. Natta", Politecnico di Milano, via Mancinelli 7, I-20131 Milano (MI), Italy.
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39
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Sliozberg YR, Yeh IC, Kröger M, Masser KA, Lenhart JL, Andzelm JW. Ordering and Crystallization of Entangled Polyethylene Melts under Uniaxial Tension: A Molecular Dynamics Study. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01538] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Yelena R. Sliozberg
- U.S. Army Research
Laboratory, Aberdeen Proving Ground, Maryland 21005, United States
- SURVICE Engineering
Company, Aberdeen Proving Ground, Maryland 21005, United States
| | - In-Chul Yeh
- U.S. Army Research
Laboratory, Aberdeen Proving Ground, Maryland 21005, United States
| | - Martin Kröger
- Polymer Physics, Department of Materials, ETH Zürich, Leopold-Ruzicka-Weg 4, CH-8093 Zürich, Switzerland
| | - Kevin A. Masser
- U.S. Army Research
Laboratory, Aberdeen Proving Ground, Maryland 21005, United States
| | - Joseph L. Lenhart
- U.S. Army Research
Laboratory, Aberdeen Proving Ground, Maryland 21005, United States
| | - Jan W. Andzelm
- U.S. Army Research
Laboratory, Aberdeen Proving Ground, Maryland 21005, United States
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40
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Dinpajooh M, Guenza MG. Coarse-graining simulation approaches for polymer melts: the effect of potential range on computational efficiency. SOFT MATTER 2018; 14:7126-7144. [PMID: 30070292 DOI: 10.1039/c8sm00868j] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The integral equation coarse-graining (IECG) approach is a promising high-level coarse-graining (CG) method for polymer melts, with variable resolution from soft spheres to multi CG sites, which preserves the structural and thermodynamical consistencies with the related atomistic simulations. When compared to the atomistic description, the procedure of coarse-graining results in smoother free energy surfaces, longer-ranged potentials, a decrease in the number of interaction sites for a given polymer, and more. Because these changes have competing effects on the computational efficiency of the CG model, care needs to be taken when studying the effect of coarse-graining on the computational speed-up in CG molecular dynamics simulations. For instance, treatment of long-range CG interactions requires the selection of cutoff distances that include the attractive part of the effective CG potential and force. In particular, we show how the complex nature of the range and curvature of the effective CG potential, the selection of a suitable CG timestep, the choice of the cutoff distance, the molecular dynamics algorithms, and the smoothness of the CG free energy surface affect the efficiency of IECG simulations. By direct comparison with the atomistic simulations of relatively short chain polymer melts, we find that the overall computational efficiency is highest for the highest level of CG (soft spheres), with an overall improvement of the computational efficiency being about 106-108 for various CG levels/resolutions. Therefore, the IECG method can have important applications in molecular dynamics simulations of polymeric systems. Finally, making use of the standard spatial decomposition algorithm, the parallel scalability of the IECG simulations for various levels of CG is presented. Optimal parallel scaling is observed for a reasonably large number of processors. Although this study is performed using the IECG approach, its results on the relation between the level of CG and the computational efficiency are general and apply to any properly-constructed CG model.
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Affiliation(s)
- Mohammadhasan Dinpajooh
- Department of Chemistry and Biochemistry, and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, USA.
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41
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Guenza MG, Dinpajooh M, McCarty J, Lyubimov IY. Accuracy, Transferability, and Efficiency of Coarse-Grained Models of Molecular Liquids. J Phys Chem B 2018; 122:10257-10278. [DOI: 10.1021/acs.jpcb.8b06687] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. G. Guenza
- Department of Chemistry and Biochemistry and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, United States
| | - M. Dinpajooh
- Department of Chemistry and Biochemistry and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, United States
| | - J. McCarty
- Department of Chemistry and Biochemistry and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, United States
| | - I. Y. Lyubimov
- Department of Chemistry and Biochemistry and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, United States
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42
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Verho T, Paajanen A, Vaari J, Laukkanen A. Crystal Growth in Polyethylene by Molecular Dynamics: The Crystal Edge and Lamellar Thickness. Macromolecules 2018; 51:4865-4873. [PMID: 30258252 PMCID: PMC6150721 DOI: 10.1021/acs.macromol.8b00857] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/14/2018] [Indexed: 11/30/2022]
Abstract
We carried out large-scale atomistic molecular dynamics simulations to study the growth of twin lamellar crystals of polyethylene initiated by small crystal seeds. By examining the size distribution of the stems-straight crystalline polymer segments-we show that the crystal edge has a parabolic profile. At the growth front, there is a layer of stems too short to be stable, and new stable stems are formed within this layer, leading to crystal growth. Away from the edge, the lengthening of the stems is limited by a lack of available slack length in the chains. This frustration can be relieved by mobile crystal defects that allow topological relaxation by traversing through the crystal. The results shed light on the process of polymer crystal growth and help explain initial thickness selection and lamellar thickening.
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Affiliation(s)
- Tuukka Verho
- VTT Technical Research Centre of Finland
Ltd., Espoo, Finland
| | - Antti Paajanen
- VTT Technical Research Centre of Finland
Ltd., Espoo, Finland
| | - Jukka Vaari
- VTT Technical Research Centre of Finland
Ltd., Espoo, Finland
| | - Anssi Laukkanen
- VTT Technical Research Centre of Finland
Ltd., Espoo, Finland
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43
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Zhang W, Larson RG. Direct All-Atom Molecular Dynamics Simulations of the Effects of Short Chain Branching on Polyethylene Oligomer Crystal Nucleation. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00958] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wenlin Zhang
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Ronald G. Larson
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
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44
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Xie C, Tang X, Yang J, Xu T, Tian F, Li L. Stretch-Induced Coil–Helix Transition in Isotactic Polypropylene: A Molecular Dynamics Simulation. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00325] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Chun Xie
- National Synchrotron Radiation Lab, CAS Key Laboratory of Soft Matter Chemistry, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, University of Science and Technology of China, Hefei, China
| | - Xiaoliang Tang
- National Synchrotron Radiation Lab, CAS Key Laboratory of Soft Matter Chemistry, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, University of Science and Technology of China, Hefei, China
| | - Junsheng Yang
- National Synchrotron Radiation Lab, CAS Key Laboratory of Soft Matter Chemistry, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, University of Science and Technology of China, Hefei, China
- Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin, China
| | - Tingyu Xu
- National Synchrotron Radiation Lab, CAS Key Laboratory of Soft Matter Chemistry, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, University of Science and Technology of China, Hefei, China
| | - Fucheng Tian
- National Synchrotron Radiation Lab, CAS Key Laboratory of Soft Matter Chemistry, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, University of Science and Technology of China, Hefei, China
| | - Liangbin Li
- National Synchrotron Radiation Lab, CAS Key Laboratory of Soft Matter Chemistry, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, University of Science and Technology of China, Hefei, China
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45
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Cheerla R, Krishnan M. Molecular mechanism of melting of a helical polymer crystal: Role of conformational order, packing and mobility of polymers. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.01.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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46
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Ramos J, Vega J, Martínez-Salazar J. Predicting experimental results for polyethylene by computer simulation. Eur Polym J 2018. [DOI: 10.1016/j.eurpolymj.2017.12.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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47
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Dinpajooh M, Guenza MG. On the Density Dependence of the Integral Equation Coarse-Graining Effective Potential. J Phys Chem B 2017; 122:3426-3440. [DOI: 10.1021/acs.jpcb.7b10494] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mohammadhasan Dinpajooh
- Department of Chemistry and Biochemistry, and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, United States
| | - Marina G. Guenza
- Department of Chemistry and Biochemistry, and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, United States
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48
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Zhou Y, Milner ST. Short-Time Dynamics Reveals Tg Suppression in Simulated Polystyrene Thin Films. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b00921] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Yuxing Zhou
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Scott T. Milner
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
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49
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Moyassari A, Unge M, Hedenqvist MS, Gedde UW, Nilsson F. First-principle simulations of electronic structure in semicrystalline polyethylene. J Chem Phys 2017; 146:204901. [PMID: 28571365 PMCID: PMC5440234 DOI: 10.1063/1.4983650] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 05/04/2017] [Indexed: 12/02/2022] Open
Abstract
In order to increase our fundamental knowledge about high-voltage cable insulation materials, realistic polyethylene (PE) structures, generated with a novel molecular modeling strategy, have been analyzed using first principle electronic structure simulations. The PE structures were constructed by first generating atomistic PE configurations with an off-lattice Monte Carlo method and then equilibrating the structures at the desired temperature and pressure using molecular dynamics simulations. Semicrystalline, fully crystalline and fully amorphous PE, in some cases including crosslinks and short-chain branches, were analyzed. The modeled PE had a structure in agreement with established experimental data. Linear-scaling density functional theory (LS-DFT) was used to examine the electronic structure (e.g., spatial distribution of molecular orbitals, bandgaps and mobility edges) on all the materials, whereas conventional DFT was used to validate the LS-DFT results on small systems. When hybrid functionals were used, the simulated bandgaps were close to the experimental values. The localization of valence and conduction band states was demonstrated. The localized states in the conduction band were primarily found in the free volume (result of gauche conformations) present in the amorphous regions. For branched and crosslinked structures, the localized electronic states closest to the valence band edge were positioned at branches and crosslinks, respectively. At 0 K, the activation energy for transport was lower for holes than for electrons. However, at room temperature, the effective activation energy was very low (∼0.1 eV) for both holes and electrons, which indicates that the mobility will be relatively high even below the mobility edges and suggests that charge carriers can be hot carriers above the mobility edges in the presence of a high electrical field.
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Affiliation(s)
- A Moyassari
- School of Chemical Science and Engineering, Fibre and Polymer Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - M Unge
- School of Chemical Science and Engineering, Fibre and Polymer Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - M S Hedenqvist
- School of Chemical Science and Engineering, Fibre and Polymer Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - U W Gedde
- School of Chemical Science and Engineering, Fibre and Polymer Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - F Nilsson
- School of Chemical Science and Engineering, Fibre and Polymer Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
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50
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Higuchi Y, Kubo M. Deformation and Fracture Processes of a Lamellar Structure in Polyethylene at the Molecular Level by a Coarse-Grained Molecular Dynamics Simulation. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02613] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yuji Higuchi
- Institute
for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
- PRESTO, Japan
Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Momoji Kubo
- Institute
for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
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