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Kashmari K, Patil SU, Kemppainen J, Shankara G, Odegard GM. Optimal Molecular Dynamics System Size for Increased Precision and Efficiency for Epoxy Materials. J Phys Chem B 2024; 128:4255-4265. [PMID: 38648370 DOI: 10.1021/acs.jpcb.4c00845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Molecular dynamics (MD) simulation is an important tool for predicting thermo-mechanical properties of polymer resins at the nanometer length scale, which is particularly important for efficient computationally driven design of advanced composite materials and structures. Because of the statistical nature of modeling amorphous materials on the nanometer length scale, multiple MD models (replicates) are typically built and simulated for statistical sampling of predicted properties. Larger replicates generally provide higher precision in the predictions but result in higher simulation times. Unfortunately, there is insufficient information in the literature to establish guidelines between MD model size and the resulting precision in predicted thermo-mechanical properties. The objective of this study was to determine the optimal MD model size of epoxy resin to balance efficiency and precision. The results show that an MD model size of 15,000 atoms provides for the fastest simulations without sacrificing precision in the prediction of mass density, elastic properties, strength, and thermal properties of epoxy. The results of this study are important for efficient computational process modeling and integrated computational materials engineering (ICME) for the design of next-generation composite materials for demanding applications.
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Affiliation(s)
- Khatereh Kashmari
- Michigan Technological University, Houghton, Michigan 49931, United States
| | - Sagar U Patil
- Michigan Technological University, Houghton, Michigan 49931, United States
| | - Josh Kemppainen
- Michigan Technological University, Houghton, Michigan 49931, United States
| | - Gowtham Shankara
- Michigan Technological University, Houghton, Michigan 49931, United States
| | - Gregory M Odegard
- Michigan Technological University, Houghton, Michigan 49931, United States
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Xu X, Zhao W, Wang L, Lin J, Du L. Efficient exploration of compositional space for high-performance copolymers via Bayesian optimization. Chem Sci 2023; 14:10203-10211. [PMID: 37772116 PMCID: PMC10530742 DOI: 10.1039/d3sc03174h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 09/04/2023] [Indexed: 09/30/2023] Open
Abstract
The traditional approach employed in copolymer compositional design, which relies on trial-and-error, faces low-efficiency and high-cost obstacles when attempting to simultaneously improve multiple conflicting properties. For example, designing co-cured polycyanurates that exhibit both moisture and thermal resistance, along with high modulus, is a long-term challenge because of the intrinsic trade-offs between these properties. In this work, to surmount these barriers, we developed a Bayesian optimization (BO)-guided method to expedite the discovery of co-cured polycyanurates exhibiting low water uptake, coupled with higher glass transition temperature and Young's modulus. By virtue of the knowledge of molecular simulations, benchmarking studies were carried out to develop an effective BO-guided method. Propelled by the developed method, several copolymers with improved comprehensive properties were obtained experimentally in a few iterations. This work provides guidance for efficiently designing other high-performance copolymers.
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Affiliation(s)
- Xinyao Xu
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology Shanghai 200237 China
| | - Wenlin Zhao
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology Shanghai 200237 China
| | - Liquan Wang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology Shanghai 200237 China
| | - Jiaping Lin
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology Shanghai 200237 China
| | - Lei Du
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology Shanghai 200237 China
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Chen H, Li Y, Cheng J, Luo Y, Lian Q. Directly Using Paraffin as the Toughening Agent of Epoxy Composites: An Experimental and Molecular Dynamics Simulation Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:979-988. [PMID: 36622385 DOI: 10.1021/acs.langmuir.2c02439] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
It is still a challenge in studying the toughening mechanism by well combining the experimental and atomistic molecular dynamics (MD) simulation study. This article directly introduced eicosane (C20, model compound of paraffin) into the epoxy matrix (DGEBA) by using a special epoxy resin with alkyl side chains (D12) as a compatibilizer, which was synthesized through thiol-ene click chemistry. The toughening mechanism of the ternary DGEBA/D12/C20 (EPDA-X) systems was systematically investigated by experimental and MD simulation methods. Though C20 can be well dispersed in the curing mixture, the huge polarity difference between C20 and DGEBA can be the driving force for C20 to stay away from DGEBA, demonstrating the self-assembly effect of C20 around the alkyl side chains of D12 because of the good compatibility of D12 and C20. The soft alkyl chains of D12 and C20 as well as the self-assembly effect of C20 around the D12 molecules can simultaneously improve the strength, modulus, and toughness of the EPDA-2.5 system. This article not only provides a brand new toughening strategy by directly using nonfunctional alkyl derivatives as the toughening agent of epoxy composites with superior mechanical properties but also provides a systematic MD simulation method to evaluate whether there is the interaction or not and the strength of interaction between different molecular chains so as to provide a theoretical basis for the cause of the microphase separation structure and related toughening mechanism in cross-linking networks on the atomic and molecular levels.
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Affiliation(s)
- Hongfeng Chen
- College of Materials Science and Engineering, North University of China, Taiyuan030051, China
| | - Yan Li
- Department of Materials Application Research, AVIC Manufacturing Technology Institute, Beijing100024, China
| | - Jue Cheng
- Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing100029, China
| | - Yanlong Luo
- College of Science, Nanjing Forestry University, Nanjing210037, China
| | - Qingsong Lian
- College of Materials Science and Engineering, North University of China, Taiyuan030051, China
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Ziolek RM, Santana-Bonilla A, López-Ríos de Castro R, Kühn R, Green M, Lorenz CD. Conformational Heterogeneity and Interchain Percolation Revealed in an Amorphous Conjugated Polymer. ACS NANO 2022; 16:14432-14442. [PMID: 36103148 PMCID: PMC9527807 DOI: 10.1021/acsnano.2c04794] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
Conjugated polymers are employed in a variety of application areas due to their bright fluorescence and strong biocompatibility. However, understanding the structure of amorphous conjugated polymers on the nanoscale is extremely challenging compared to their related crystalline phases. Using a bespoke classical force field, we study amorphous poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) (F8BT) with molecular dynamics simulations to investigate the role that its nanoscale structure plays in controlling its emergent (and all-important) optical properties. Notably, we show that a giant percolating cluster exists within amorphous F8BT, which has ramifications in understanding the nature of interchain species that drive the quantum yield reduction and bathochromic shift observed in conjugated polymer-based devices and nanostructures. We also show that distinct conformations can be unravelled from within the disordered structure of amorphous F8BT using a two-stage machine learning protocol, highlighting a link between molecular conformation and ring stacking propensity. This work provides predictive understanding by which to enhance the optical properties of next-generation conjugated polymer-based devices and materials by rational, simulation-led design principles.
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Affiliation(s)
- Robert M. Ziolek
- Biological
Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, United Kingdom
| | | | - Raquel López-Ríos de Castro
- Biological
Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, United Kingdom
- Department
of Chemistry, King’s College London, London, SE1 1DB, United Kingdom
| | - Reimer Kühn
- Department
of Mathematics, King’s College London, London WC2R 2LS, United Kingdom
| | - Mark Green
- Photonics
and Nanotechnology Group, Department of Physics, King’s College London, London WC2R 2LS, United
Kingdom
| | - Christian D. Lorenz
- Biological
Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, United Kingdom
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Lian Q, Chen H, Luo Y, Li Y, Cheng J, Liu Y. Toughening mechanism based on the physical entanglement of branched epoxy resin in the non-phase-separated inhomogeneous crosslinking network: An experimental and molecular dynamics simulation study. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.124754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Haber RT, Browning AR, Graves BR, Davis WP, Wiggins JS. A Molecular Dynamics Study of Monomer Melt Properties of Cyanate Ester Monomer Melt Properties. Polymers (Basel) 2022; 14:polym14061219. [PMID: 35335549 PMCID: PMC8951156 DOI: 10.3390/polym14061219] [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: 02/10/2022] [Revised: 03/07/2022] [Accepted: 03/11/2022] [Indexed: 01/27/2023] Open
Abstract
The objective of this work was to computationally predict the melting temperature and melt properties of thermosetting monomers used in aerospace applications. In this study, we applied an existing voids method by Solca. to examine four cyanate ester monomers with a wide range of melting temperatures. Voids were introduced into some simulations by removal of molecules from lattice positions to lower the free-energy barrier to melting to directly simulate the transition from a stable crystal to amorphous solid and capture the melting temperature. We validated model predictions by comparing melting temperature against previously reported literature values. Additionally, the torsion and orientational order parameters were used to examine the monomers’ freedom of motion to investigate structure–property relationships. Ultimately, the voids method provided reasonable estimates of melting temperature while the torsion and order parameter analysis provided insight into sources of the differing melt properties between the thermosetting monomers. As a whole, the results shed light on how freedom of molecular motions in the monomer melt state may affect melting temperature and can be utilized to inspire the development of thermosetting monomers with optimal monomer melt properties for demanding applications.
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Affiliation(s)
- Rebecca T. Haber
- School of Polymer Science and Engineering, University of Southern Mississippi, 118 College Dr, #5050, Hattiesburg, MS 39406, USA; (R.T.H.); (B.R.G.)
| | | | - Bayleigh R. Graves
- School of Polymer Science and Engineering, University of Southern Mississippi, 118 College Dr, #5050, Hattiesburg, MS 39406, USA; (R.T.H.); (B.R.G.)
| | - William P. Davis
- Department of Mathematics, Western Washington University, 516 High St., Bellingham, WA 98225, USA;
| | - Jeffrey S. Wiggins
- School of Polymer Science and Engineering, University of Southern Mississippi, 118 College Dr, #5050, Hattiesburg, MS 39406, USA; (R.T.H.); (B.R.G.)
- Correspondence:
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