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Moghimikheirabadi A, Kröger M, Karatrantos AV. Insights from modeling into structure, entanglements, and dynamics in attractive polymer nanocomposites. Soft Matter 2021; 17:6362-6373. [PMID: 34128028 PMCID: PMC8262555 DOI: 10.1039/d1sm00683e] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 06/08/2021] [Indexed: 05/28/2023]
Abstract
Conformations, entanglements and dynamics in attractive polymer nanocomposites are investigated in this work by means of coarse-grained molecular dynamics simulation, for both weak and strong confinements, in the presence of nanoparticles (NPs) at NP volume fractions φ up to 60%. We show that the behavior of the apparent tube diameter dapp in such nanocomposites can be greatly different from nanocomposites with nonattractive interactions. We find that this effect originates, based on a mean field argument, from the geometric confinement length dgeo at strong confinement (large φ) and not from the bound polymer layer on NPs (interparticle distance ID <2Rg) as proposed recently based on experimental measurements. Close to the NP surface, the entangled polymer mobility is reduced in attractive nanocomposites but still faster than the NP mobility for volume fractions beyond 20%. Furthermore, entangled polymer dynamics is hindered dramatically by the strong confinement created by NPs. For the first time using simulations, we show that the entangled polymer conformation, characterized by the polymer radius of gyration Rg and form factor, remains basically unperturbed by the presence of NPs up to the highest volume fractions studied, in agreement with various experiments on attractive nanocomposites. As a side-result we demonstrate that the loose concept of ID can be made a microscopically well defined quantity using the mean pore size of the NP arrangement.
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Affiliation(s)
- Ahmad Moghimikheirabadi
- Department of Materials, Polymer Physics, ETH Zurich, Leopold-Ruzicka-Weg 4, CH-8093 Zurich, Switzerland.
| | - Martin Kröger
- Department of Materials, Polymer Physics, ETH Zurich, Leopold-Ruzicka-Weg 4, CH-8093 Zurich, Switzerland.
| | - Argyrios V Karatrantos
- Materials Research and Technology, Luxembourg Institute of Science and Technology, 5, Avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg.
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Abstract
We present a coarse-grained (CG) molecular dynamics (MD) simulation study of polymer nanocomposites (PNCs) containing nanorods with homogeneous and patchy surface chemistry/functionalization, modeled with isotropic and directional nanorod-nanorod attraction, respectively. We show how the PNC morphology is impacted by the nanorod design (i.e., aspect ratio, homogeneous or patchy surface chemistry/functionalization) for nanorods with a diameter equal to the Kuhn length of the polymer in the matrix. For PNCs with 10 vol % nanorods that have an aspect ratio ≤5, we observe percolated morphology with directional nanorod-nanorod attraction and phase-separated (i.e., nanorod aggregation) morphology with isotropic nanorod-nanorod attraction. In contrast, for nanorods with higher aspect ratios, both types of attractions result in aggregated nanorods morphology due to the dominance of entropic driving forces that cause long nanorods to form orientationally ordered aggregates. For most PNCs with isotropic or directional nanorod-nanorod attractions, the average matrix polymer conformation is not perturbed by the inclusion of up to 20 vol % nanorods. The polymer chains in contact with nanorods (i.e., interfacial chains) are on average extended and statistically different from the conformations the matrix chains adopt in the pure melt state (with no nanorods); in contrast, the polymer chains far from nanorods (i.e., bulk chains) adopt the same conformations as the matrix chains adopt in the pure melt state. We also study the effect of other parameters, such as attraction strength, nanorod volume fraction, and matrix chain length, for PNCs with isotropic or directional nanorod-nanorod attractions. Collectively, our results provide valuable design rules to achieve specific PNC morphologies (i.e., dispersed, aggregated, percolated, and orientationally aligned nanorods) for various potential applications.
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Affiliation(s)
- Shizhao Lu
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, Delaware 19716, United States
| | - Zijie Wu
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, Delaware 19716, United States
| | - Arthi Jayaraman
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, Delaware 19716, United States.,Department of Materials Science and Engineering, University of Delaware, 201 DuPont Hall, Newark, Delaware 19716, United States
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Zhang X, Wei W, Jin X, Xiong H. Chain Dimension and Dynamics of Polymers in Well-Defined Non-sticky Nanocomposites of Molecular Nanoparticle Polyhedral Oligomeric Silsesquioxane/Poly(butylene oxide). Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00158] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xinlin Zhang
- Department of Polymer Science, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Wei Wei
- Department of Polymer Science, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Xin Jin
- Department of Polymer Science, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Huiming Xiong
- Department of Polymer Science, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
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Affiliation(s)
| | | | | | - Elliot P. Gilbert
- Australian Centre for Neutron Scattering, Australia Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
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Abstract
Grafting polymers to nanoparticle surfaces influences properties from the conformation of the polymer chains to the dispersion and assembly of nanoparticles within a polymeric material. Recently, a small body of work has begun to address the question of how grafting polymers to a nanoparticle surface impacts chain dynamics, and the resulting physical properties of a material. This Review discusses recent work that characterizes the structure and dynamics of polymers that are grafted to nanoparticles and opportunities for future research. Starting from the case of a single polymer chain attached to a nanoparticle core, this Review follows the structure of the chains as grafting density increases, and how this structure slows relaxation of polymer chains and affects macroscopic material properties.
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Affiliation(s)
- Michael J A Hore
- Department of Macromolecular Science & Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, USA.
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Jouault N, Kumar SK, Smalley RJ, Chi C, Moneta R, Wood B, Salerno H, Melnichenko YB, He L, Guise WE, Hammouda B, Crawford MK. Do Very Small POSS Nanoparticles Perturb s-PMMA Chain Conformations? Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00432] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Nicolas Jouault
- Sorbonne Université, CNRS, Laboratoire Physicochimie des Electrolytes et des Nanosystèmes InterfaciauX, PHENIX F-75005 Paris, France
| | - Sanat K. Kumar
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Robert J. Smalley
- DuPont Central
Research
and Development, E400/5424, Wilmington, Delaware 19880-0400, United States
| | - Changzai Chi
- DuPont Central
Research
and Development, E400/5424, Wilmington, Delaware 19880-0400, United States
| | - Robert Moneta
- DuPont Central
Research
and Development, E400/5424, Wilmington, Delaware 19880-0400, United States
| | - Barbara Wood
- DuPont Central
Research
and Development, E400/5424, Wilmington, Delaware 19880-0400, United States
| | - Holly Salerno
- DuPont Central
Research
and Development, E400/5424, Wilmington, Delaware 19880-0400, United States
| | - Yuri B. Melnichenko
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393, United States
| | - Lilin He
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393, United States
| | - William E. Guise
- DuPont Central
Research
and Development, E400/5424, Wilmington, Delaware 19880-0400, United States
- Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Ave., Lemont, Illinois 60439, United States
| | - Boualem Hammouda
- NIST Center for Neutron
Research, Gaithersburg, Maryland 20879-8562, United States
| | - Michael K. Crawford
- DuPont Central
Research
and Development, E400/5424, Wilmington, Delaware 19880-0400, United States
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, United States
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