1
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Kim M, Choi W, Lee CH, Kim DW. 2D MOFs and Zeolites for Composite Membrane and Gas Separation Applications: A Brief Review. ACS MATERIALS AU 2024; 4:148-161. [PMID: 38496048 PMCID: PMC10941277 DOI: 10.1021/acsmaterialsau.3c00072] [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: 08/31/2023] [Revised: 11/16/2023] [Accepted: 11/20/2023] [Indexed: 03/19/2024]
Abstract
Commercial membranes have predominantly been fabricated from polymers due to their economic viability and processability. This choice offers significant advantages in energy efficiency, cost-effectiveness, and operational simplicity compared to conventional separation techniques like distillation. However, polymeric membranes inherently exhibit a trade-off between their permeability and selectivity, which is summarized in the Robeson upper bound. To potentially surpass these limitations, mixed-matrix membranes (MMMs) can be an alternative solution, which can be constructed by combining polymers with inorganic additives such as metal-organic frameworks (MOFs) and zeolites. Incorporating high-aspect-ratio fillers like MOF nanosheets and zeolite nanosheets is of significant importance. This incorporation not only enhances the efficiency of separation processes but also reinforces the mechanical robustness of the membranes. We outline synthesis techniques for producing two-dimensional (2D) crystals (including nanocrystals with high aspect ratio) and provide examples of their integration into membranes to customize separation performances. Moreover, we propose a potential trajectory for research in the area of high-aspect-ratio materials-based MMMs, supported by a mathematical-model-based performance prediction.
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Affiliation(s)
- Minsu Kim
- Department of Chemical and
Biomolecular Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Wooyoung Choi
- Department of Chemical and
Biomolecular Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Choong Hoo Lee
- Department of Chemical and
Biomolecular Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Dae Woo Kim
- Department of Chemical and
Biomolecular Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-gu, Seoul 03722, Republic of Korea
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2
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Huo Z, Arora S, Kong VA, Myrga BJ, Statt A, Laaser JE. Effect of Polymer Composition and Morphology on Mechanochemical Activation in Nanostructured Triblock Copolymers. Macromolecules 2023; 56:1845-1854. [PMID: 36938512 PMCID: PMC10018773 DOI: 10.1021/acs.macromol.2c02475] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/07/2023] [Indexed: 03/06/2023]
Abstract
The effect of composition and morphology on mechanochemical activation in nanostructured block copolymers was investigated in a series of poly(methyl methacrylate)-block-poly(n-butyl acrylate)-block-poly(methyl methacrylate) (PMMA-b-PnBA-b-PMMA) triblock copolymers containing a force-responsive spiropyran unit in the center of the rubbery PnBA midblock. Triblock copolymers with identical PnBA midblocks and varying lengths of PMMA end-blocks were synthesized from a spiropyran-containing macroinitiatior via atom transfer radical polymerization, yielding polymers with volume fractions of PMMA ranging from 0.21 to 0.50. Characterization by transmission electron microscopy revealed that the polymers self-assembled into spherical and cylindrical nanostructures. Simultaneous tensile tests and optical measurements revealed that mechanochemical activation is strongly correlated to the chemical composition and morphologies of the triblock copolymers. As the glassy (PMMA) block content is increased, the overall activation increases, and the onset of activation occurs at lower strain but higher stress, which agrees with predictions from our previous computational work. These results suggest that the self-assembly of nanostructured morphologies can play an important role in controlling mechanochemical activation in polymeric materials and provide insights into how polymer composition and morphology impact molecular-scale force distributions.
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Affiliation(s)
- Zijian Huo
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States
| | - Swati Arora
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States
| | - Victoria A. Kong
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States
| | - Brandon J. Myrga
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States
| | - Antonia Statt
- Materials
Science and Engineering, Grainger College of Engineering, University of Illinois, Urbana−Champaign, Illinois 61801, United States
| | - Jennifer E. Laaser
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States
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3
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Huo Z, Skala SJ, Falck LR, Laaser JE, Statt A. Computational Study of Mechanochemical Activation in Nanostructured Triblock Copolymers. ACS POLYMERS AU 2022; 2:467-477. [PMID: 36536889 PMCID: PMC9756960 DOI: 10.1021/acspolymersau.2c00031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 06/17/2023]
Abstract
Force-driven chemical reactions have emerged as an attractive platform for diverse applications in polymeric materials. However, the microscopic chain conformations and topologies necessary for efficiently transducing macroscopic forces to the molecular scale are not well-understood. In this work, we use a coarse-grained model to investigate the impact of network-like topologies on mechanochemical activation in self-assembled triblock copolymers. We find that mechanochemical activation during tensile deformation depends strongly on both the polymer composition and chain conformation in these materials. Activation primarily occurs in the tie chains connecting different glassy domains and in loop chains that are hooked onto each other by physical entanglements. Activation also requires a higher stress in materials having a higher glassy block content. Overall, the lamellar samples show the highest percent activation at high stress. In contrast, at low stress, the spherical morphology, which has the lowest glassy fraction, shows the highest activation. Additionally, we observe a spatial pattern of activation, which appears to be tied to distortion of the self-assembled morphology. Higher activation is observed in the tips of the chevrons formed during deformation of lamellar samples as well as in the centers between the cylinders in the cylindrical morphology. Our work shows that changes in the network-like topology in different morphologies significantly impact mechanochemical activation efficiencies in these materials, suggesting that this area will be a fruitful avenue for further experimental research.
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Affiliation(s)
- Zijian Huo
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States
| | - Stephen J Skala
- Materials
Science and Engineering, Grainger College of Engineering, University of Illinois, Urbana−Champaign, Illinois 61801, United States
| | - Lavinia R Falck
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States
| | - Jennifer E Laaser
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States
| | - Antonia Statt
- Materials
Science and Engineering, Grainger College of Engineering, University of Illinois, Urbana−Champaign, Illinois 61801, United States
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4
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Micro-mechanical properties of foamed polymer rehabilitation material: A molecular dynamics study. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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5
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Effects of Mechanical Stress on Insulation Structure and Performance of HV Cable. Polymers (Basel) 2022; 14:polym14142927. [PMID: 35890703 PMCID: PMC9317511 DOI: 10.3390/polym14142927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 07/14/2022] [Accepted: 07/15/2022] [Indexed: 12/10/2022] Open
Abstract
Mechanical stresses generated during manufacturing and laying process of high voltage cables can result in degradation of insulation properties, affecting the stable operation of the transmission system. Traditional test methods for testing the effect of mechanical stress on the insulation properties of polyethylene still have some shortcomings to be explored and it is able to explain the changes of the insulation properties of polyethylene under mechanical stress from a microscopic perspective. In order to further study the effect of stress on the insulation properties of polyethylene, microstructural changes, the breakdown field strength, conductivity and charge distribution of polyethylene at different elongation rates are investigated by a combination of experimental and molecular dynamics simulations. The results show that the increase in stress leads to a decrease in crystallinity and microcrystalline size of the material decrease. The untwisting and orientation of the polyethylene molecular chains during the stretching process can create cavities, resulting in an uneven sample distribution and thickness reduction, leading to a reduction in the breakdown field strength. Meanwhile, some crystal regions are transformed into amorphous regions. The loose amorphous regions facilitate the directional migration of carriers, resulting in the increase of conductivity. When the elongation ratio is smaller, the distance between the molecular chains increases and the trap depth of the specimen becomes shallower. This facilitates the migration of ions and electrons and increases the rate of decay of the surface potential. When the stretch is further increased, new traps are created by broken molecular chains to limit the movement of charges, decreasing the decay rate of the surface potential and reducing the insulation properties of the polyethylene. Meanwhile, the molecular dynamics model of semi-crystalline polyethylene was developed to observe the microstructure and energy changes during the stretching process. The conclusions in terms of tensile tests were verified from a microscopic perspective.
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6
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Higuchi Y. Coarse-grained molecular dynamics simulations of void generation and growth processes in the fracture of the lamellar structure of polyethylene. Phys Rev E 2021; 103:042502. [PMID: 34005872 DOI: 10.1103/physreve.103.042502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 03/25/2021] [Indexed: 06/12/2023]
Abstract
We investigate the void generation and growth process in semicrystalline polymers by large-scale coarse-grained molecular dynamics simulations. Voids are generated in the amorphous layers and grow spherically and then cylindrically, consistent with the results of previous experiments. Interestingly, the fusion of voids is indicated to enlarge the voids in the direction perpendicular to the stretching direction, but not beyond the crystalline layers. The orientational order along the stretching direction increased sharply before void generation, but the increase leveled off afterward. The simulations also clearly reveal that the crystalline layers break but do not bend in the fragmentation process. The dependence of the void growth process on stretching velocity and the stability levels of voids at constant strain are also discussed.
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Affiliation(s)
- Yuji Higuchi
- Institute for Solid State Physics, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8581, Japan and Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
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7
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Higuchi Y. Stress Transmitters at the Molecular Level in the Deformation and Fracture Processes of the Lamellar Structure of Polyethylene via Coarse-Grained Molecular Dynamics Simulations. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00636] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yuji Higuchi
- Institute for Solid State Physics, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8581, Japan
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai, Miyagi 980-8577, Japan
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8
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Nanovoids in uniaxially elongated polymer network filled with polydisperse nanoparticles via coarse-grained molecular dynamics simulation and two-dimensional scattering patterns. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.04.040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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9
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Higuchi Y. Fracture processes of crystalline polymers using coarse-grained molecular dynamics simulations. Polym J 2018. [DOI: 10.1038/s41428-018-0067-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10
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Higuchi Y, Saito K, Sakai T, Gong JP, Kubo M. Fracture Process of Double-Network Gels by Coarse-Grained Molecular Dynamics Simulation. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00124] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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
- Institute for Solid State Physics, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8581, Japan
| | - Keisuke Saito
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Takamasa Sakai
- PRESTO, Japan Science and Technology Agency (JST),
4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Jian Ping Gong
- Faculty of Advanced Life Science and Soft Matter GI-CoRE, Hokkaido University, N21W11, Kita-ku, Sapporo 001-0021, Japan
| | - Momoji Kubo
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
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11
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Morthomas J, Fusco C, Zhai Z, Lame O, Perez M. Crystallization of finite-extensible nonlinear elastic Lennard-Jones coarse-grained polymers. Phys Rev E 2017; 96:052502. [PMID: 29347659 DOI: 10.1103/physreve.96.052502] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Indexed: 06/07/2023]
Abstract
The ability of a simple coarse-grained finite-extensible nonlinear elastic (FENE) Lennard-Jones (LJ) polymer model to be crystallized is investigated by molecular dynamics simulations. The optimal FENE Lennard-Jones parameter combinations (ratio between FENE and LJ equilibrium distances) and the optimal lattice parameters are calculated for five different perfect crystallite structures: simple tetragonal, body-centered tetragonal, body-centered orthorhombic, hexagonal primitive, and hexagonal close packed. It was found that the most energetically favorable structure is the body-centered orthorhombic. Starting with an equilibrated polymer liquid and with the optimal parameters found for the body-centered orthorhombic, an isothermal treatment led to the formation of large lamellar crystallites with a typical chain topology: folded, loop, and tie chains, and with a crystallinity of about 60%-70%, similar to real semicrystalline polymers. This simple coarse-grained Lennard-Jones model provides a qualitative tool to study semicrystalline microstructures for polymers.
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Affiliation(s)
- Julien Morthomas
- INSA de Lyon, Université de Lyon, MATEIS, UMR CNRS 5510, 69621 Villeurbanne, France
| | - Claudio Fusco
- INSA de Lyon, Université de Lyon, MATEIS, UMR CNRS 5510, 69621 Villeurbanne, France
| | - Zengqiang Zhai
- INSA de Lyon, Université de Lyon, MATEIS, UMR CNRS 5510, 69621 Villeurbanne, France
| | - Olivier Lame
- INSA de Lyon, Université de Lyon, MATEIS, UMR CNRS 5510, 69621 Villeurbanne, France
| | - Michel Perez
- INSA de Lyon, Université de Lyon, MATEIS, UMR CNRS 5510, 69621 Villeurbanne, France
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12
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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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13
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Oya Y, Kikugawa G, Okabe T. Clustering Approach for Multidisciplinary Optimum Design of Cross‐Linked Polymer. MACROMOL THEOR SIMUL 2016. [DOI: 10.1002/mats.201600072] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yutaka Oya
- Department of Aerospace Engineering Tohoku University 6‐6‐01, Aramaki‐Aza‐Aoba Aoba‐ku, Sendai Miyagi 980‐8579 Japan
| | - Gota Kikugawa
- Institute of Fluid Science Tohoku University 2‐2‐1, Katahira Aoba‐ku, Sendai Miyagi 980‐8577 Japan
| | - Tomonaga Okabe
- Department of Aerospace Engineering Tohoku University 6‐6‐01, Aramaki‐Aza‐Aoba Aoba‐ku, Sendai Miyagi 980‐8579 Japan
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14
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Guo J, Zhang X, Gu H, Wang Y, Yan X, Ding D, Long J, Tadakamalla S, Wang Q, Khan MA, Liu J, Zhang X, Weeks BL, Sun L, Young DP, Wei S, Guo Z. Reinforced magnetic epoxy nanocomposites with conductive polypyrrole nanocoating on nanomagnetite as a coupling agent. RSC Adv 2014. [DOI: 10.1039/c4ra07359b] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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15
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Makke A, Lame O, Perez M, Barrat JL. Nanoscale Buckling in Lamellar Block Copolymers: A Molecular Dynamics Simulation Approach. Macromolecules 2013. [DOI: 10.1021/ma400514h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ali Makke
- LPMCN,
UMR CNRS 5586, Université de Lyon I, Université de Lyon, F69622 Villeurbanne, France
- INSA
Lyon, MATEIS, UMR CNRS 5510, Université de Lyon, F69621 Villeurbanne, France
- Institut
Charles Delaunay, LASMIS UMR CNRS 6279, Ecole Polytechnique Féminine, F10004 Troyes, France
| | - Olivier Lame
- INSA
Lyon, MATEIS, UMR CNRS 5510, Université de Lyon, F69621 Villeurbanne, France
| | - Michel Perez
- INSA
Lyon, MATEIS, UMR CNRS 5510, Université de Lyon, F69621 Villeurbanne, France
| | - Jean-Louis Barrat
- LIPhy,
UMR CNRS 5588, Université Joseph Fourier, Grenoble, F38402 Grenoble, France
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16
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Solar M, Meyer H, Gauthier C. Analysis of local properties during a scratch test on a polymeric surface using molecular dynamics simulations. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2013; 36:29. [PMID: 23526081 DOI: 10.1140/epje/i2013-13029-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 02/21/2013] [Indexed: 06/02/2023]
Abstract
This work demonstrates a possible route to connect a particle (chain) based understanding with continuum mechanical questions about contact mechanics. The bond orientation, chain conformation and stress field of a polymer film were analyzed during scratch tests (tangential contact) using a molecular dynamics (MD) simulation approach. Scratch tests with a conical tip at constant scratching velocity were simulated on linear amorphous polymer surfaces at various temperatures and roughnesses of the tip and for various interactions between the tip and the particles of the polymer chains. The second Legendre polynomial (computed for small domains around the tip) gave the bond orientation inside the polymer film during sliding of the tip. The gyration tensor (layer-resolved in the direction of the polymer film thickness) provided information about the conformation of the polymer chains. These results allowed us to argue in favor of Briscoe's hypothesis (thin film sheared vs. "bulk" compressive behavior) concerning the friction properties of the polymer surfaces. Finally, the first stress measurements of the virial stress tensor (in sub-boxes placed in the MD cell) revealed a complex combination between compressive hydrostatic pressure and shear stress, which may be interpreted as a complex sheared domain at the interface.
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Affiliation(s)
- M Solar
- Institut Charles Sadron (UPR22-CNRS), University of Strasbourg, 23 rue du Loess, BP 84047, F-67034, Strasbourg, France.
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17
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Makke A, Lame O, Perez M, Barrat JL. Influence of Tie and Loop Molecules on the Mechanical Properties of Lamellar Block Copolymers. Macromolecules 2012. [DOI: 10.1021/ma301286y] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ali Makke
- Université de Lyon, INSA
Lyon, MATEIS, UMR CNRS 5510, F69621 Villeurbanne,
France
- Université
de Lyon, Université
Lyon I, LPMCN, UMR CNRS 5586, F69622 Villeurbanne,
France
| | - Olivier Lame
- Université de Lyon, INSA
Lyon, MATEIS, UMR CNRS 5510, F69621 Villeurbanne,
France
| | - Michel Perez
- Université de Lyon, INSA
Lyon, MATEIS, UMR CNRS 5510, F69621 Villeurbanne,
France
| | - Jean-Louis Barrat
- Université
Joseph-Fourier,
Grenoble, LIPhy, UMR CNRS 5588, Grenoble,
France
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18
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Froltsov VA, Klüppel M, Raos G. Molecular dynamics simulation of rupture in glassy polymer bridges within filler aggregates. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:041801. [PMID: 23214604 DOI: 10.1103/physreve.86.041801] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 07/25/2012] [Indexed: 06/01/2023]
Abstract
We present a series of nonequilibrium molecular dynamics simulations, investigating the rupture mechanisms in glassy polymer films confined between two solid surfaces. Such systems provide a useful model for the strong nonlinear reinforcement of rubber by colloidal filler particles. Depending on the degree of confinement three qualitatively different rupture modes have been found, which originate from the interplay of internal (polymer-polymer) and external (polymer-wall) interactions. In very thin films we observe the formation and stretching of many single-chain bridges between the confining surfaces. Progressing to thicker samples we observe fewer bridges, consisting of bundled polymer chains, and eventually just one large bridge in thick specimens. The yield stress and the elongational modulus of the polymer films have been calculated from the stress-strain curves at various temperatures and confinements and their behavior has been analyzed in terms of polymer-polymer and polymer-surface interaction energies. The thinnest films (5 monomer diameters) are always glassy in our simulations, while the others display a glass transition temperature around 0.50-0.55 (in units ε(0)/k(B) of the Lennard-Jones interaction energy), depending on their thickness. This range of values, which has been determined using both the nonequilibrium tensile simulations and equilibrium diffusion data, agrees with the transition temperature previously found by shear simulations [Baljon and Robbins, Science 271, 482 (1996)].
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Affiliation(s)
- Vladimir A Froltsov
- Deutsches Institut für Kautschuktechnologie e.V., Eupener Strasse 33, D-30519 Hannover, Germany
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19
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Solar M, Meyer H, Gauthier C, Fond C, Benzerara O, Schirrer R, Baschnagel J. Mechanical behavior of linear amorphous polymers: comparison between molecular dynamics and finite-element simulations. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:021808. [PMID: 22463237 DOI: 10.1103/physreve.85.021808] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Revised: 11/29/2011] [Indexed: 05/31/2023]
Abstract
This paper studies the rheology of weakly entangled polymer melts and films in the glassy domain and near the rubbery domain using two different methods: molecular dynamics (MD) and finite element (FE) simulations. In a first step, the uniaxial mechanical behavior of a bulk polymer sample is studied by means of particle-based MD simulations. The results are in good agreement with experimental data, and mechanical properties may be computed from the simulations. This uniaxial mechanical behavior is then implemented in FE simulations using an elasto-viscoelasto-viscoplastic constitutive law in a continuum mechanics (CM) approach. In a second step, the mechanical response of a polymer film during an indentation test is modeled with the MD method and with the FE simulations using the same constitutive law. Good agreement is found between the MD and CM results. This work provides evidence in favor of using MD simulations to investigate the local physics of contact mechanics, since the volume elements studied are representative and thus contain enough information about the microstructure of the polymer model, while surface phenomena (adhesion and surface tension) are naturally included in the MD approach.
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Affiliation(s)
- Mathieu Solar
- Institut Charles Sadron UPR 0022, University of Strasbourg, Campus CNRS de Cronenbourg, 23 Rue du Loess, BP 84047, F-67034 Strasbourg Cedex 2, France
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20
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Makke A, Perez M, Rottler J, Lame O, Barrat JL. Predictors of Cavitation in Glassy Polymers under Tensile Strain: A Coarse-Grained Molecular Dynamics Investigation. MACROMOL THEOR SIMUL 2011. [DOI: 10.1002/mats.201100006] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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21
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Lomakin J, Huber PA, Eichler C, Arakane Y, Kramer KJ, Beeman RW, Kanost MR, Gehrke SH. Mechanical properties of the beetle elytron, a biological composite material. Biomacromolecules 2010; 12:321-35. [PMID: 21189044 DOI: 10.1021/bm1009156] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We determined the relationship between composition and mechanical properties of elytra (modified forewings that are composed primarily of highly sclerotized dorsal and less sclerotized ventral cuticles) from the beetles Tribolium castaneum (red flour beetle) and Tenebrio molitor (yellow mealworm). Elytra of both species have similar mechanical properties at comparable stages of maturation (tanning). Shortly after adult eclosion, the elytron of Tenebrio is ductile and soft with a Young's modulus (E) of 44 ± 8 MPa, but it becomes brittle and stiff with an E of 2400 ± 1100 MPa when fully tanned. With increasing tanning, dynamic elastic moduli (E') increase nearly 20-fold, whereas the frequency dependence of E' diminishes. These results support the hypothesis that cuticle tanning involves cross-linking of components, while drying to minimize plasticization has a lesser impact on cuticular stiffening and frequency dependence. Suppression of the tanning enzymes laccase-2 (TcLac2) or aspartate 1-decarboxylase (TcADC) in Tribolium altered mechanical characteristics consistent with hypotheses that (1) ADC suppression favors formation of melanic pigment with a decrease in protein cross-linking and (2) Lac2 suppression reduces both cuticular pigmentation and protein cross-linking.
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Affiliation(s)
- Joseph Lomakin
- Chemical and Petroleum Engineering, University of Kansas, Lawrence, Kansas 66045, USA
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Léonforte F. Evolution of entanglements during the response to a uniaxial deformation of lamellar triblock copolymers and polymer glasses. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 82:041802. [PMID: 21230303 DOI: 10.1103/physreve.82.041802] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2010] [Indexed: 05/30/2023]
Abstract
Using coarse-grained molecular-dynamics simulations, a generic styrene-block-butadiene-block-styrene triblock copolymer under lamellar conformation is used in order to investigate the mutual entanglement evolution when a structure of alternating glassy (S)/rubbery (B) layers is submitted to an imposed deformation. By varying the amount of loop chains between each phase, i.e., noncrossing chains, it is possible to generate different types of S/B interface definitions. A specific boundary driven tensile strain protocol has been developed in order to mimic "real" experiments and measure the stress-strain curve. The same protocol is also applied to a reference state consisting in a directed glassy homopolymers, as well as to an isotropic glassy polymer. The evolution of initial mutual entanglements from the undeformed samples during the whole deformation process is monitored. It is shown for all considered systems that initial entanglements mostly participate to the preyield regime of the stress-strain curve and that this network is debonded during the strain-hardening regime. For triblocks with a non-null amount of crossing chains, the lower the amount is, the longer the memory effect of the initial entanglement network in the postyield regime is. On the fly distributions of entanglements, which depart from the postyield regime, depict memory effects and long-time correlations during the strain-hardening regime. For triblocks, loop chains reinforce these effects.
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Affiliation(s)
- F Léonforte
- Institut für Theoretische Physik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
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Rottler J. Fracture in glassy polymers: a molecular modeling perspective. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:463101. [PMID: 21715863 DOI: 10.1088/0953-8984/21/46/463101] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Over the past 25 years, molecular modeling and simulations have provided important insights into the physics of deformation and fracture of glassy polymers. This review presents an overview of key results discussed in the context of experimentally observed polymer behavior. Both atomistic and coarse-grained polymer models have been used in different deformation protocols to study elastic properties, shear yielding, creep, physical aging, strain hardening and crazing. Simulations reproduce most of the macroscopic features of plasticity in polymer glasses such as stress-strain relations and creep response, and reveal information about the underlying atomistic processes. Trends of the shear yield stress with loading conditions, temperature and strain rate, and the atomistic dynamics under load have been systematically explored. Most polymers undergo physical aging, which leads to a history-dependent mechanical response. Simulations of strain hardening and crazing demonstrate the nature of polymer entanglements in the glassy state and the role of local plasticity and provide insight into the origin of fracture toughness of amorphous polymers.
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Affiliation(s)
- Jörg Rottler
- Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1, Canada
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