1
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Moussavi A, Pal S, Wu Z, Keten S. Characterizing the shear response of polymer-grafted nanoparticles. J Chem Phys 2024; 160:134903. [PMID: 38573850 DOI: 10.1063/5.0188494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 03/18/2024] [Indexed: 04/06/2024] Open
Abstract
Grafting polymer chains to the surface of nanoparticles overcomes the challenge of nanoparticle dispersion within nanocomposites and establishes high-volume fractions that are found to enable enhanced material mechanical properties. This study utilizes coarse-grained molecular dynamics simulations to quantify how the shear modulus of polymer-grafted nanoparticle (PGN) systems in their glassy state depends on parameters such as strain rate, nanoparticle size, grafting density, and chain length. The results are interpreted through further analysis of the dynamics of chain conformations and volume fraction arguments. The volume fraction of nanoparticles is found to be the most influential variable in deciding the shear modulus of PGN systems. A simple rule of mixture is utilized to express the monotonic dependence of shear modulus on the volume fraction of nanoparticles. Due to the reinforcing effect of nanoparticles, shortening the grafted chains results in a higher shear modulus in PGNs, which is not seen in linear systems. These results offer timely insight into calibrating molecular design parameters for achieving the desired mechanical properties in PGNs.
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Affiliation(s)
- Arman Moussavi
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Subhadeep Pal
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Zhenghao Wu
- Department of Chemistry, Xi'an Jiaotong Liverpool University, Suzhou, People's Republic of China
| | - Sinan Keten
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois 60208, USA
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208, USA
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2
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Gresham IJ, Lilley SG, Nelson ARJ, Koynov K, Neto C. Nanostructure Explains the Behavior of Slippery Covalently Attached Liquid Surfaces. Angew Chem Int Ed Engl 2023; 62:e202308008. [PMID: 37550243 DOI: 10.1002/anie.202308008] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/05/2023] [Accepted: 08/07/2023] [Indexed: 08/09/2023]
Abstract
Slippery covalently-attached liquid surfaces (SCALS) with low contact angle hysteresis (CAH, <5°) and nanoscale thickness display impressive anti-adhesive properties, similar to lubricant-infused surfaces. Their efficacy is generally attributed to the liquid-like mobility of the constituent tethered chains. However, the precise physico-chemical properties that facilitate this mobility are unknown, hindering rational design. This work quantifies the chain length, grafting density, and microviscosity of a range of polydimethylsiloxane (PDMS) SCALS, elucidating the nanostructure responsible for their properties. Three prominent methods are used to produce SCALS, with characterization carried out via single-molecule force measurements, neutron reflectometry, and fluorescence correlation spectroscopy. CO2 snow-jet cleaning was also shown to reduce the CAH of SCALS via a modification of their grafting density. SCALS behavior can be predicted by reduced grafting density, Σ, with the lowest water CAH achieved at Σ≈2. This study provides the first direct examination of SCALS grafting density, chain length, and microviscosity and supports the hypothesis that SCALS properties stem from a balance of layer uniformity and mobility.
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Affiliation(s)
- Isaac J Gresham
- School of Chemistry and the University of Sydney Nano Institute, The University of Sydney, Sydney, NSW, Australia
| | - Seamus G Lilley
- School of Chemistry and the University of Sydney Nano Institute, The University of Sydney, Sydney, NSW, Australia
| | - Andrew R J Nelson
- Australian Center for Neutron Scattering, ANSTO, Sydney, NSW, Australia
| | - Kaloian Koynov
- Max Planck Institute for Polymer Research, Mainz, Germany
| | - Chiara Neto
- School of Chemistry and the University of Sydney Nano Institute, The University of Sydney, Sydney, NSW, Australia
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3
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Dietz JD, Kröger M, Hoy RS. Validation and Refinement of Unified Analytic Model for Flexible and Semiflexible Polymer Melt Entanglement. Macromolecules 2022; 55:3613-3626. [PMID: 35571224 PMCID: PMC9097689 DOI: 10.1021/acs.macromol.1c02597] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/23/2022] [Indexed: 11/28/2022]
Abstract
We combine molecular dynamics simulations and topological analyses (TA) to validate and refine a recently proposed unified analytic model [Hoy, R. S.; Kröger, M. Phys. Rev. Lett. 2020, 124, 147801] for the reduced entanglement length, tube diameter, and plateau modulus of polymer melts. While the functional forms of the previously published expressions are insensitive to the choice of the TA method and N e -estimator, obtaining better statistics and eliminating all known sources of systematic error in the N e -estimation alters their numerical coefficients. Our revised expressions quantitatively match bead-spring simulation data over the entire range of chain stiffnesses for which systems remain isotropic, semiquantitatively match all available experimental data for flexible, semiflexible, and stiff polymer melts (including new data for conjugated polymers that lie in a previously unpopulated stiffness regime), and outperform previously developed unified scaling theories.
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Affiliation(s)
- Joseph D. Dietz
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Martin Kröger
- Department of Materials, Polymer Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Robert S. Hoy
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
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4
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Desroches G, Wang Y, Kubiak J, Macfarlane R. Crosslinking of Pressure-Sensitive Adhesives with Polymer-Grafted Nanoparticles. ACS APPLIED MATERIALS & INTERFACES 2022; 14:9579-9586. [PMID: 35147026 DOI: 10.1021/acsami.1c22997] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Nanocomposite filler particles provide multiple routes to mechanically reinforce pressure-sensitive adhesives (PSAs), as their large surface area to volume ratios provide a means of effectively crosslinking multiple polymer chains. A major advancement could therefore be enabled by the design of a particle architecture that forms multiple physical and chemical interactions with the surrounding polymer matrix, while simultaneously ensuring particle dispersion and preventing particle aggregation. Understanding how such multivalent interactions between a nanoparticle crosslinking point and the PSA polymer affect material mechanical performance would provide both useful scientific knowledge on the mechanical structure-property relationships in polymer composites, as well as a new route to synthesizing useful PSA materials. Herein, we report the use of polymer-grafted nanoparticles (PGNPs) composed of poly(n-butyl acrylate-co-acrylic acid) chains grafted to SiO2 nanoparticle (NP) surfaces to cohesively reinforce PSA films against shear stress without compromising their adhesive properties. The use of acrylic acid-decorated PGNPs allows for ionic crosslinking via metal salt coordination to be used in conjunction with physical entanglement, yielding 33% greater shear resistance and up to 3-fold longer holding times under static load. In addition, the effects of material parameters such as PGNP/crosslinker loading, polymer graft length, and core nanoparticle size on mechanical properties are also explored, providing insights into the use of PGNPs for the rational design of polymer composite-based PSAs.
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Affiliation(s)
- Griffen Desroches
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Yuping Wang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Joshua Kubiak
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Robert Macfarlane
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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5
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Dietz JD, Hoy RS. Facile equilibration of well-entangled semiflexible bead-spring polymer melts. J Chem Phys 2022; 156:014103. [PMID: 34998323 DOI: 10.1063/5.0072386] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The widely used double-bridging hybrid (DBH) method for equilibrating simulated entangled polymer melts [Auhl et al., J. Chem. Phys. 119, 12718-12728 (2003)] loses its effectiveness as chain stiffness increases into the semiflexible regime because the energy barriers associated with double-bridging Monte Carlo moves become prohibitively high. Here we overcome this issue by combining DBH with the use of core-softened pair potentials. This reduces the energy barriers substantially, allowing us to equilibrate melts with N ≃ 40Ne and chain stiffnesses all the way up to the isotropic-nematic transition using simulations of no more than 100 × 106 time steps. For semiflexible chains, our method is several times faster than the standard DBH; we exploit this speedup to develop improved expressions for Kremer-Grest melts' chain-stiffness-dependent Kuhn length ℓK and entanglement length Ne.
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Affiliation(s)
- Joseph D Dietz
- Department of Physics, University of South Florida, Tampa, Florida 33620, USA
| | - Robert S Hoy
- Department of Physics, University of South Florida, Tampa, Florida 33620, USA
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6
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Parisi D, Camargo M, Makri K, Gauthier M, Likos CN, Vlassopoulos D. Effect of softness on glass melting and re-entrant solidification in mixtures of soft and hard colloids. J Chem Phys 2021; 155:034901. [PMID: 34293891 DOI: 10.1063/5.0055381] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a systematic investigation of the structure and dynamic properties of model soft-hard colloidal mixtures. Results of a coarse-grained theoretical model are contrasted with rheological data, where the soft and hard colloids are mimicked by large star polymers with high functionality as the soft component and smaller stars with ultrahigh functionality as the hard one. Previous work by us revealed the recovery of the ergodicity of glassy soft star solutions and subsequent arrested phase separation and re-entrant solid transition upon progressive addition of small hard depletants. Here, we use different components to show that a small variation in softness has a significant impact on the state diagram of such mixtures. In particular, we establish that rendering the soft component more penetrable and modifying the size ratio bring about a remarkable shift in both the phase separation region and the glass-melting line so that the region of restored ergodicity can be notably enhanced and extended to much higher star polymer concentrations than for pure systems. We further rationalize our findings by analyzing the features of the depletion interaction induced by the smaller component that result from the interplay between the size ratio and the softness of the large component. These results demonstrate the great sensitivity of the phase behavior of entropic mixtures to small changes in the molecular architecture of the soft stars and point to the importance of accounting for details of the internal microstructure of soft colloidal particles for tailoring the flow properties of soft composites.
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Affiliation(s)
- Daniele Parisi
- FORTH, Institute of Electronic Structure and Laser, 70013 Heraklion, Crete, Greece
| | - Manuel Camargo
- CICBA & FIMEB, Universidad Antonio Nariño-Campus Farallones, Km 18 via Cali-Jamundi, 760030 Cali, Colombia
| | - Kalliopi Makri
- FORTH, Institute of Electronic Structure and Laser, 70013 Heraklion, Crete, Greece
| | - Mario Gauthier
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Christos N Likos
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
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7
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Li SJ, Shi X. Tailoring Antifouling Properties of Nanocarriers via Entropic Collision of Polymer Grafting. ACS NANO 2021; 15:5725-5734. [PMID: 33710849 DOI: 10.1021/acsnano.1c01173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Polymer graftings (PGs) are widely employed in antifouling surfaces and drug delivery systems to regulate the interaction with a foreign environment. Through molecular dynamics simulations and scaling theory analysis, we investigate the physical antifouling properties of PGs via their collision behaviors. Compared with mushroom-like PGs with low grafting density, we find brush-like PGs with high grafting density could generate large deformation-induced entropic repulsive force during a collision, revealing a microscopic mechanism for the hop motions of polymer-grafted nanoparticles for drug delivery observed in experiment. In addition, the collision elasticity of PGs is found to decay with the collision velocity by a power law, i.e., a concise dynamic scaling despite the complex process involved, which is beyond expectation. These results elucidate the dynamic interacting mechanism of PGs, which are of immediate interest for a fundamental understanding of the antifouling performance of PGs and the rational design of PG-coated nanoparticles in nanomedicine for drug delivery.
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Affiliation(s)
- Shu-Jia Li
- Laboratory of Theoretical and Computational Nanoscience, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, No. 11 ZhongGuanCun BeiYiTiao, Beijing 100190, China
| | - Xinghua Shi
- Laboratory of Theoretical and Computational Nanoscience, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, No. 11 ZhongGuanCun BeiYiTiao, Beijing 100190, China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China
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8
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Yu Y, Brió Pérez M, Cao C, de Beer S. Switching (bio-) adhesion and friction in liquid by stimulus responsive polymer coatings. Eur Polym J 2021. [DOI: 10.1016/j.eurpolymj.2021.110298] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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9
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Buhl KB, Agergaard AH, Lillethorup M, Nikolajsen JP, Pedersen SU, Daasbjerg K. Polymer Brush Coating and Adhesion Technology at Scale. Polymers (Basel) 2020; 12:E1475. [PMID: 32630138 PMCID: PMC7407671 DOI: 10.3390/polym12071475] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 06/25/2020] [Accepted: 06/29/2020] [Indexed: 01/09/2023] Open
Abstract
Creating strong joints between dissimilar materials for high-performance hybrid products places high demands on modern adhesives. Traditionally, adhesion relies on the compatibility between surfaces, often requiring the use of primers and thick bonding layers to achieve stable joints. The coatings of polymer brushes enable the compatibilization of material surfaces through precise control over surface chemistry, facilitating strong adhesion through a nanometer-thin layer. Here, we give a detailed account of our research on adhesion promoted by polymer brushes along with examples from industrial applications. We discuss two fundamentally different adhesive mechanisms of polymer brushes, namely (1) physical bonding via entanglement and (2) chemical bonding. The former mechanism is demonstrated by e.g., the strong bonding between poly(methyl methacrylate) (PMMA) brush coated stainless steel and bulk PMMA, while the latter is shown by e.g., the improved adhesion between silicone and titanium substrates, functionalized by a hydrosilane-modified poly(hydroxyethyl methacrylate) (PHEMA) brush. This review establishes that the clever design of polymer brushes can facilitate strong bonding between metals and various polymer materials or compatibilize fillers or nanoparticles with otherwise incompatible polymeric matrices. To realize the full potential of polymer brush functionalized materials, we discuss the progress in the synthesis of polymer brushes under ambient and scalable industrial conditions, and present recent developments in atom transfer radical polymerization for the large-scale production of brush-modified materials.
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Affiliation(s)
- Kristian Birk Buhl
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK 8000 Aarhus C, Denmark; (K.B.B.); (A.H.A.); (J.P.N.)
| | - Asger Holm Agergaard
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK 8000 Aarhus C, Denmark; (K.B.B.); (A.H.A.); (J.P.N.)
| | | | - Jakob Pagh Nikolajsen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK 8000 Aarhus C, Denmark; (K.B.B.); (A.H.A.); (J.P.N.)
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Steen Uttrup Pedersen
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Kim Daasbjerg
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK 8000 Aarhus C, Denmark; (K.B.B.); (A.H.A.); (J.P.N.)
- Radisurf ApS, Arresoevej 5B, DK-8240 Risskov, Denmark
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10
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Li J, Lu Y, Hao L, Zhang R, Ding M, Shi T. Dynamics Transition of Polymer Films Induced by Polymer–Obstacle Entanglements on Rough Surfaces. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jiaxiang Li
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China
| | - Yuyuan Lu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Lili Hao
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China
| | - Ran Zhang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Mingming Ding
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Tongfei Shi
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China
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11
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Hsu HP, Kremer K. Clustering of Entanglement Points in Highly Strained Polymer Melts. Macromolecules 2019; 52:6756-6772. [PMID: 31534275 PMCID: PMC6740293 DOI: 10.1021/acs.macromol.9b01120] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/13/2019] [Indexed: 11/30/2022]
Abstract
Polymer melts undergoing large deformation by elongation are studied by molecular dynamics simulations of bead-spring chains in melts. By applying a primitive path analysis to strongly deformed polymer melts, the role of topological constraints in highly entangled polymer melts is investigated and quantified. We show that the overall, large scale conformations of the primitive paths (PPs) of stretched chains follow affine deformation while the number and the distribution of entanglement points along the PPs do not. Right after deformation, PPs of chains retract in both directions parallel and perpendicular to the elongation. Upon further relaxation we observe a long-lived clustering of entanglement points. Together with the delayed relaxation time this leads to a metastable inhomogeneous distribution of topological constraints in the melts.
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Affiliation(s)
- Hsiao-Ping Hsu
- Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Kurt Kremer
- Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
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12
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Karatrantos A, Composto RJ, Winey KI, Kröger M, Clarke N. Modeling of Entangled Polymer Diffusion in Melts and Nanocomposites: A Review. Polymers (Basel) 2019; 11:E876. [PMID: 31091725 PMCID: PMC6571671 DOI: 10.3390/polym11050876] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/06/2019] [Accepted: 05/09/2019] [Indexed: 11/29/2022] Open
Abstract
This review concerns modeling studies of the fundamental problem of entangled (reptational) homopolymer diffusion in melts and nanocomposite materials in comparison to experiments. In polymer melts, the developed united atom and multibead spring models predict an exponent of the molecular weight dependence to the polymer diffusion very similar to experiments and the tube reptation model. There are rather unexplored parameters that can influence polymer diffusion such as polymer semiflexibility or polydispersity, leading to a different exponent. Models with soft potentials or slip-springs can estimate accurately the tube model predictions in polymer melts enabling us to reach larger length scales and simulate well entangled polymers. However, in polymer nanocomposites, reptational polymer diffusion is more complicated due to nanoparticle fillers size, loading, geometry and polymer-nanoparticle interactions.
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Affiliation(s)
- Argyrios Karatrantos
- Materials Research and Technology, Luxembourg Institute of Science and Technology, 5, Avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg.
| | - Russell J Composto
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Karen I Winey
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Martin Kröger
- Polymer Physics, Department of Materials, ETH Zurich, Leopold-Ruzicka-Weg 4, CH-8093 Zurich, Switzerland.
| | - Nigel Clarke
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, UK.
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13
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Scaling and Interactions of Linear and Ring Polymer Brushes via DPD Simulations. Polymers (Basel) 2019; 11:polym11030541. [PMID: 30960525 PMCID: PMC6473544 DOI: 10.3390/polym11030541] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/14/2019] [Accepted: 03/18/2019] [Indexed: 11/17/2022] Open
Abstract
Single and double layers of polymer coated surfaces are investigated by means of Dissipative Particle Dynamics (DPD), focusing on the difference between grafted ring and linear chains. Several different surface coverages σ , as well as chain lengths N and brush separations D, are analyzed for athermal, i.e., good solvent, conditions. The size in the form of the radius of gyration R g , the shape as asphericity δ ∗ , and orientation β ∗ , as well as density profiles as functions of distance from grafting plane ρ ( z ) , are studied. The effect of an added bond repulsion potential to suppress bond crossing in DPD is analyzed. Scaling laws of R g and its components R g ⊥ and R g ∥ are investigated. We find R g ∝ N ν , ν = 0.588 for surface coverages below the overlap surface concentration σ ∗ . For σ > σ ∗ we find R g ⊥ ∝ N ν ⊥ , ν ⊥ ≅ 1 and R g ∥ ∝ N ν ∥ , ν ∥ = 1 / 2 of ring brushes with the standard DPD model and ν ∥ ≅ 2 / 5 with added bond repulsion. The σ dependence of the radius of gyration was found to be R g ∝ σ μ with μ = 1 / 3 for surface coverages grater than σ ∗ . The perpendicular component R g ⊥ scales independent of the bond repulsion potential as R g ⊥ ∝ σ μ ⊥ , μ ⊥ = 1 / 3 , whereas the scaling of the parallel component exhibits a topological repulsion dependence R g ∥ ∝ σ μ ∥ , μ ∥ = - 1 / 12 for standard DPD and μ ∥ = - 1 / 6 for bond repulsion.
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14
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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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15
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Singh M, Kang C, Ilg P, Crockett R, Kröger M, Spencer ND. Combined Experimental and Simulation Studies of Cross-Linked Polymer Brushes under Shear. Macromolecules 2018; 51:10174-10183. [PMID: 32063653 PMCID: PMC7018396 DOI: 10.1021/acs.macromol.8b01363] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 10/24/2018] [Indexed: 12/11/2022]
Abstract
We have studied the effect of cross-linking on the tribological behavior of polymer brushes using a combined experimental and theoretical approach. Tribological and indentation measurements on poly(glycidyl methacrylate) brushes and gels in the presence of dimethylformamide solvent were obtained by means of atomic force microscopy. To complement experiments, we have performed corresponding molecular dynamics (MD) simulations of a generic bead-spring model in the presence of explicit solvent and cross-linkers. Our study shows that cross-linking leads to an increase in friction between polymer brushes and a counter-surface. The coefficient of friction increases with increasing degree of cross-linking and decreases with increasing length of the cross-linker chains. We find that the brush-forming polymer chains in the outer layer play a significant role in reducing friction at the interface.
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Affiliation(s)
- Manjesh
K. Singh
- Laboratory
for Surface Science and Technology, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Chengjun Kang
- Laboratory
for Surface Science and Technology, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Patrick Ilg
- School
of Mathematical, Physical and Computational Sciences, University of Reading, Reading RG6 6AX, United Kingdom
| | - Rowena Crockett
- Swiss
Federal Laboratories for Materials Science and Technology (EMPA), CH-8600 Dübendorf, Switzerland
| | - Martin Kröger
- Polymer
Physics, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Nicholas D. Spencer
- Laboratory
for Surface Science and Technology, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
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16
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Kirk J, Kröger M, Ilg P. Surface Disentanglement and Slip in a Polymer Melt: A Molecular Dynamics Study. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01865] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jack Kirk
- School of Mathematical, Physical and Computational Sciences, University of Reading, Reading RG6 6AX, U.K
| | - Martin Kröger
- Polymer Physics, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Patrick Ilg
- School of Mathematical, Physical and Computational Sciences, University of Reading, Reading RG6 6AX, U.K
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17
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Kumar SK, Ganesan V, Riggleman RA. Perspective: Outstanding theoretical questions in polymer-nanoparticle hybrids. J Chem Phys 2018; 147:020901. [PMID: 28711055 DOI: 10.1063/1.4990501] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
This topical review discusses the theoretical progress made in the field of polymer nanocomposites, i.e., hybrid materials created by mixing (typically inorganic) nanoparticles (NPs) with organic polymers. It primarily focuses on the outstanding issues in this field and is structured around five separate topics: (i) the synthesis of functionalized nanoparticles; (ii) their phase behavior when mixed with a homopolymer matrix and their assembly into well-defined superstructures; (iii) the role of processing on the structures realized by these hybrid materials and the role of the mobilities of the different constituents; (iv) the role of external fields (electric, magnetic) in the active assembly of the NPs; and (v) the engineering properties that result and the factors that control them. While the most is known about topic (ii), we believe that significant progress needs to be made in the other four topics before the practical promise offered by these materials can be realized. This review delineates the most pressing issues on these topics and poses specific questions that we believe need to be addressed in the immediate future.
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Affiliation(s)
- Sanat K Kumar
- Department of Chemical Engineering, Columbia University, New York, New York 10025, USA
| | - Venkat Ganesan
- Department of Chemical Engineering, University of Texas, Austin, Texas 78712, USA
| | - Robert A Riggleman
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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18
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Hou JX, Yu XC, Huang ZW. Primitive path analysis of linear polymer embedded in post array. JOURNAL OF POLYMER RESEARCH 2017. [DOI: 10.1007/s10965-017-1258-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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19
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Chen WL, Cordero R, Tran H, Ober CK. 50th Anniversary Perspective: Polymer Brushes: Novel Surfaces for Future Materials. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b00450] [Citation(s) in RCA: 296] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Wei-Liang Chen
- Department of Materials Science & Engineering, ‡Smith School of Chemical and Biomolecular Engineering, and §Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Roselynn Cordero
- Department of Materials Science & Engineering, ‡Smith School of Chemical and Biomolecular Engineering, and §Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Hai Tran
- Department of Materials Science & Engineering, ‡Smith School of Chemical and Biomolecular Engineering, and §Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Christopher K. Ober
- Department of Materials Science & Engineering, ‡Smith School of Chemical and Biomolecular Engineering, and §Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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20
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Affiliation(s)
- Jack Kirk
- School of Mathematical,
Physical
and Computational Sciences, University of Reading, Reading RG6 6AX, U.K
| | - Patrick Ilg
- School of Mathematical,
Physical
and Computational Sciences, University of Reading, Reading RG6 6AX, U.K
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21
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Vogiatzis GG, Theodorou DN. Multiscale Molecular Simulations of Polymer-Matrix Nanocomposites: or What Molecular Simulations Have Taught us About the Fascinating Nanoworld. ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING : STATE OF THE ART REVIEWS 2017; 25:591-645. [PMID: 29962833 PMCID: PMC6003436 DOI: 10.1007/s11831-016-9207-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 12/20/2016] [Indexed: 06/08/2023]
Abstract
Following the substantial progress in molecular simulations of polymer-matrix nanocomposites, now is the time to reconsider this topic from a critical point of view. A comprehensive survey is reported herein providing an overview of classical molecular simulations, reviewing their major achievements in modeling polymer matrix nanocomposites, and identifying several open challenges. Molecular simulations at multiple length and time scales, working hand-in-hand with sensitive experiments, have enhanced our understanding of how nanofillers alter the structure, dynamics, thermodynamics, rheology and mechanical properties of the surrounding polymer matrices.
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Affiliation(s)
- Georgios G. Vogiatzis
- School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus, 15780 Athens, Greece
- Present Address: Department of Mechanical Engineering, Eindhoven University of Technology, PO Box 513, 5600MB Eindhoven, The Netherlands
| | - Doros N. Theodorou
- School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus, 15780 Athens, Greece
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22
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Ge T, Tzoumanekas C, Anogiannakis SD, Hoy RS, Robbins MO. Entanglements in Glassy Polymer Crazing: Cross-Links or Tubes? Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b02125] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ting Ge
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Christos Tzoumanekas
- Department
of Materials Science and Engineering, School of Chemical Engineering, National Technical University of Athens, Athens 15780, Greece
| | - Stefanos D. Anogiannakis
- Department
of Materials Science and Engineering, School of Chemical Engineering, National Technical University of Athens, Athens 15780, Greece
| | - Robert S. Hoy
- Department
of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Mark O. Robbins
- Department
of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, United States
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23
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Meng D, Kumar SK, Ge T, Robbins MO, Grest GS. Crazing of nanocomposites with polymer-tethered nanoparticles. J Chem Phys 2016; 145:094902. [DOI: 10.1063/1.4961872] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Dong Meng
- Department of Chemical Engineering, Columbia University, New York, New York 10027, USA
| | - Sanat K. Kumar
- Department of Chemical Engineering, Columbia University, New York, New York 10027, USA
| | - Ting Ge
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Mark O. Robbins
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Gary S. Grest
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
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24
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Akkilic N, Molenaar R, Claessens MMAE, Blum C, de Vos WM. Monitoring the Switching of Single BSA-ATTO 488 Molecules Covalently End-Attached to a pH-Responsive PAA Brush. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:8803-8811. [PMID: 27525503 DOI: 10.1021/acs.langmuir.6b01064] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We describe a novel combination of a responsive polymer brush and a fluorescently labeled biomolecule, where the position of the biomolecule can be switched from inside to outside the brush and vice versa by a change in pH. For this, we grafted ultrathin, amino-terminated poly(acrylic acid) brushes to glass and silicon substrates. Individual bovine serum albumin (BSA) molecules labeled with fluorophore ATTO 488 were covalently end-attached to the polymers in this brush using a bis-N-succinimidyl-(pentaethylene glycol) linker. We investigated the dry layer properties of the brush-protein ensemble, and it is swelling behavior using spectroscopic ellipsometry. Total internal reflection fluorescence (TIRF) microscopy enabled us to study the distance-dependent switching of the fluorescently labeled protein molecules. The fluorescence emission from the labeled proteins ceased (out-state) when the polymer chains stretched away from the interface under basic pH conditions, and fluorescence recurred (in-state) when the chains collapsed under acidic conditions. Moreover, TIRF allowed us to study the fluorescence switching behavior of fluorescently labeled BSA molecules down to the single-molecule level, and we demonstrate that this switching is fast but that the exact intensity during the in-state is the result of a more random process. Control experiments verify that the switching behavior is directly correlated to the responsive behavior of the polymer brush. We propose this system as a platform for switchable sensor applications but also as a method to study the swelling and collapse of individual polymer chains in a responsive polymer brush.
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Affiliation(s)
- Namik Akkilic
- Membrane Science and Technology, and ‡Nanobiophysics, Mesa+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Robert Molenaar
- Membrane Science and Technology, and ‡Nanobiophysics, Mesa+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Mireille M A E Claessens
- Membrane Science and Technology, and ‡Nanobiophysics, Mesa+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Christian Blum
- Membrane Science and Technology, and ‡Nanobiophysics, Mesa+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Wiebe M de Vos
- Membrane Science and Technology, and ‡Nanobiophysics, Mesa+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
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25
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Poling-Skutvik R, Mongcopa KIS, Faraone A, Narayanan S, Conrad JC, Krishnamoorti R. Structure and Dynamics of Interacting Nanoparticles in Semidilute Polymer Solutions. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01277] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
| | | | - Antonio Faraone
- National Institute
of Standards and Technology Center for Neutron Research, Gaithersburg, Maryland 20899, United States
| | - Suresh Narayanan
- Advanced
Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
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26
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Singh MK, Ilg P, Espinosa-Marzal RM, Spencer ND, Kröger M. Influence of Chain Stiffness, Grafting Density and Normal Load on the Tribological and Structural Behavior of Polymer Brushes: A Nonequilibrium-Molecular-Dynamics Study. Polymers (Basel) 2016; 8:E254. [PMID: 30974530 PMCID: PMC6431904 DOI: 10.3390/polym8070254] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 06/24/2016] [Accepted: 07/01/2016] [Indexed: 12/16/2022] Open
Abstract
We have performed coarse-grained molecular-dynamics simulations on both flexible and semiflexible multi-bead-spring model polymer brushes in the presence of explicit solvent particles, to explore their tribological and structural behaviors. The effect of stiffness and tethering density on equilibrium-brush height is seen to be well reproduced within a Flory-type theory. After discussing the equilibrium behavior of the model brushes, we first study the shearing behavior of flexible chains at different grafting densities covering brush and mushroom regimes. Next, we focus on the effect of chain stiffness on the tribological behavior of polymer brushes. The tribological properties are interpreted by means of the simultaneously recorded density profiles. We find that the friction coefficient decreases with increasing persistence length, both in velocity and separation-dependency studies, over the stiffness range explored in this work.
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Affiliation(s)
- Manjesh K Singh
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland.
| | - Patrick Ilg
- School of Mathematical and Physical Sciences, University of Reading, Reading RG6 6AX, UK.
| | - Rosa M Espinosa-Marzal
- Laboratory for Smart Interfaces in Environmental Nanotechnology, Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Champaign, IL 61801, USA.
| | - Nicholas D Spencer
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland.
| | - Martin Kröger
- Polymer Physics, Department of Materials, ETH Zurich, CH⁻8093 Zurich, Switzerland.
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27
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A New Self-Consistent Field Model of Polymer/Nanoparticle Mixture. Sci Rep 2016; 6:20355. [PMID: 26829174 PMCID: PMC4734332 DOI: 10.1038/srep20355] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/30/2015] [Indexed: 01/04/2023] Open
Abstract
Field-theoretical method is efficient in predicting assembling structures of polymeric systems. However, it’s challenging to generalize this method to study the polymer/nanoparticle mixture due to its multi-scale nature. Here, we develop a new field-based model which unifies the nanoparticle description with the polymer field within the self-consistent field theory. Instead of being “ensemble-averaged” continuous distribution, the particle density in the final morphology can represent individual particles located at preferred positions. The discreteness of particle density allows our model to properly address the polymer-particle interface and the excluded-volume interaction. We use this model to study the simplest system of nanoparticles immersed in the dense homopolymer solution. The flexibility of tuning the interfacial details allows our model to capture the rich phenomena such as bridging aggregation and depletion attraction. Insights are obtained on the enthalpic and/or entropic origin of the structural variation due to the competition between depletion and interfacial interaction. This approach is readily extendable to the study of more complex polymer-based nanocomposites or biology-related systems, such as dendrimer/drug encapsulation and membrane/particle assembly.
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28
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Luo C, Sommer JU. Role of Thermal History and Entanglement Related Thickness Selection in Polymer Crystallization. ACS Macro Lett 2016; 5:30-34. [PMID: 35668599 DOI: 10.1021/acsmacrolett.5b00668] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using molecular dynamics simulations and primitive path analysis, we show that hot entangled polymer melts can crystallize faster with higher crystallinities and larger crystalline stem lengths, as compared to cold melts under rapid quenching conditions or during cold-crystallization. This counterintuitive phenomenon similar to the so-called Mpemba effect observed for water can be explained by the temperature dependence of entanglements. Our results demonstrate the key role of the entanglement state for crystallization properties and provide a new approach to understand the role of thermal history and to the open question of thickness selection in polymer crystallization.
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Affiliation(s)
- Chuanfu Luo
- Leibniz-Institut
für Polymerforschung Dresden e.V., Hohe Strasse 6, 01069 Dresden, Germany
| | - Jens-Uwe Sommer
- Leibniz-Institut
für Polymerforschung Dresden e.V., Hohe Strasse 6, 01069 Dresden, Germany
- Institut
für Theoretische Physik, Technische Universität Dresden, Zellescher Weg 17, 01062 Dresden, Germany
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29
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Moreira LA, Zhang G, Müller F, Stuehn T, Kremer K. Direct Equilibration and Characterization of Polymer Melts for Computer Simulations. MACROMOL THEOR SIMUL 2015. [DOI: 10.1002/mats.201500013] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Livia A. Moreira
- Max-Planck-Institut für Polymerforschung; Ackermannweg 10 55128 Mainz Germany
| | - Guojie Zhang
- Max-Planck-Institut für Polymerforschung; Ackermannweg 10 55128 Mainz Germany
| | - Franziska Müller
- Max-Planck-Institut für Polymerforschung; Ackermannweg 10 55128 Mainz Germany
| | - Torsten Stuehn
- Max-Planck-Institut für Polymerforschung; Ackermannweg 10 55128 Mainz Germany
| | - Kurt Kremer
- Max-Planck-Institut für Polymerforschung; Ackermannweg 10 55128 Mainz Germany
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30
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Liu Z, Hao B, Zhang Y. Control interfacial properties and tensile strength of glass fibre/PP composites by grafting poly(ethylene glycol) chains on glass fibre surface. RSC Adv 2015. [DOI: 10.1039/c5ra05491e] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The interfacial adhesion increased as the grafted PEG chains became longer.
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Affiliation(s)
- Zeyu Liu
- Xinjiang Technical Institute of Physics and Chemistry
- The Chinese Academy of Sciences
- Urumqi 830011
- People's Republic of China
- University of the Chinese Academy of Sciences
| | - Bin Hao
- Xinjiang Technical Institute of Physics and Chemistry
- The Chinese Academy of Sciences
- Urumqi 830011
- People's Republic of China
- University of the Chinese Academy of Sciences
| | - Yagang Zhang
- Xinjiang Technical Institute of Physics and Chemistry
- The Chinese Academy of Sciences
- Urumqi 830011
- People's Republic of China
- Department of Chemical & Environmental Engineering
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31
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Ge T, Grest GS, Robbins MO. Tensile Fracture of Welded Polymer Interfaces: Miscibility, Entanglements, and Crazing. Macromolecules 2014. [DOI: 10.1021/ma501473q] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ting Ge
- Department
of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, United States
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Gary S. Grest
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Mark O. Robbins
- Department
of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, United States
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32
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Ge T, Robbins MO, Perahia D, Grest GS. Healing of polymer interfaces: Interfacial dynamics, entanglements, and strength. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:012602. [PMID: 25122327 DOI: 10.1103/physreve.90.012602] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Indexed: 05/23/2023]
Abstract
Self-healing of polymer films often takes place as the molecules diffuse across a damaged region, above their melting temperature. Using molecular dynamics simulations we probe the healing of polymer films and compare the results with those obtained for thermal welding of homopolymer slabs. These two processes differ from each other in their interfacial structure since damage leads to increased polydispersity and more short chains. A polymer sample was cut into two separate films that were then held together in the melt state. The recovery of the damaged film was followed as time elapsed and polymer molecules diffused across the interface. The mass uptake and formation of entanglements, as obtained from primitive path analysis, are extracted and correlated with the interfacial strength obtained from shear simulations. We find that the diffusion across the interface is significantly faster in the damaged film compared to welding because of the presence of short chains. Though interfacial entanglements increase more rapidly for the damaged films, a large fraction of these entanglements are near chain ends. As a result, the interfacial strength of the healing film increases more slowly than for welding. For both healing and welding, the interfacial strength saturates as the bulk entanglement density is recovered across the interface. However, the saturation strength of the damaged film is below the bulk strength for the polymer sample. At saturation, cut chains remain near the healing interface. They are less entangled and as a result they mechanically weaken the interface. Chain stiffness increases the density of entanglements, which increases the strength of the interface. Our results show that a few entanglements across the interface are sufficient to resist interfacial chain pullout and enhance the mechanical strength.
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Affiliation(s)
- Ting Ge
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Mark O Robbins
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Dvora Perahia
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, USA
| | - Gary S Grest
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
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33
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Li Y, Krentz TM, Wang L, Benicewicz BC, Schadler LS. Ligand engineering of polymer nanocomposites: from the simple to the complex. ACS APPLIED MATERIALS & INTERFACES 2014; 6:6005-6021. [PMID: 24476387 DOI: 10.1021/am405332a] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
One key to optimizing the performance of polymer nanocomposites for high-tech applications is surface ligand engineering of the nanofiller, which has been used to either tune the nanofiller morphology or introduce additional functionalities. Ligand engineering can be relatively simple such as a single population of short molecules on the nanoparticle surface designed for matrix compatibility. It can also have complexity that includes bimodal (or multimodal) populations of ligands that enable relatively independent control of enthalpic and entropic interactions between the nanofiller and matrix as well as introduce additional functionality and dynamic control. In this Spotlight on Applications, we provide a brief review into the use of brush ligands to tune the thermodynamic interactions between nanofiller and matrix and then focus on the potential for surface ligand engineering to create exciting nanocomposites properties for optoelectronic and dielectric applications.
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Affiliation(s)
- Ying Li
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
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34
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Koski J, Chao H, Riggleman RA. Field theoretic simulations of polymer nanocomposites. J Chem Phys 2013; 139:244911. [DOI: 10.1063/1.4853755] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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35
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Ge T, Grest GS, Robbins MO. Structure and Strength at Immiscible Polymer Interfaces. ACS Macro Lett 2013; 2:882-886. [PMID: 35607008 DOI: 10.1021/mz400407m] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thermal welding of polymer-polymer interfaces is important for integrating polymeric elements into devices. When two different polymers are joined, the strength of the weld depends critically on the degree of immiscibility. We perform large-scale molecular dynamics simulations of the structure-strength relation at immiscible polymer interfaces. Our simulations show that immiscibility arrests interdiffusion and limits the equilibrium interfacial width. Even for weakly immiscible films, the narrow interface is unable to transfer stress upon deformation as effectively as the bulk material, and chain pullout at the interface becomes the dominant failure mechanism. This greatly reduces the interfacial strength. The weak response of immiscible interfaces is shown to arise from an insufficient density of entanglements across the interface. We demonstrate that there is a threshold interfacial width below which no significant entanglements can form between opposite sides to strengthen the interface.
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Affiliation(s)
- Ting Ge
- Department
of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Gary S. Grest
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Mark O. Robbins
- Department
of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, United States
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36
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Ge T, Pierce F, Perahia D, Grest GS, Robbins MO. Molecular dynamics simulations of polymer welding: strength from interfacial entanglements. PHYSICAL REVIEW LETTERS 2013; 110:098301. [PMID: 23496750 DOI: 10.1103/physrevlett.110.098301] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Indexed: 05/23/2023]
Abstract
Large-scale simulations of thermal welding of polymers are performed to investigate the rise of mechanical strength at the polymer-polymer interface with the welding time t(w). The welding process is at the core of integrating polymeric elements into devices as well as in the thermal induced healing of polymers, processes that require the development of interfacial strength equal to that of the bulk. Our simulations show that the interfacial strength saturates at the bulk shear strength long before polymers diffuse by their radius of gyration. Along with the strength increase, the dominant failure mode changes from chain pullout at the interface to chain scission as in the bulk. The formation of sufficient entanglements across the interface, which we track using a primitive path analysis, is required to arrest catastrophic chain pullout at the interface. The bulk response is not fully recovered until the density of entanglements at the interface reaches the bulk value. Moreover, the increase of interfacial strength before saturation is proportional to the number of interfacial entanglements between chains from opposite sides.
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Affiliation(s)
- Ting Ge
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
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37
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Anogiannakis SD, Tzoumanekas C, Theodorou DN. Microscopic Description of Entanglements in Polyethylene Networks and Melts: Strong, Weak, Pairwise, and Collective Attributes. Macromolecules 2012. [DOI: 10.1021/ma300912z] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stefanos D. Anogiannakis
- School of Chemical Engineering, Zografou Campus, National Technical University of Athens, GR-15780 Athens,
Greece
| | - Christos Tzoumanekas
- School of Chemical Engineering, Zografou Campus, National Technical University of Athens, GR-15780 Athens,
Greece
- Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven,
The Netherlands
| | - Doros N. Theodorou
- School of Chemical Engineering, Zografou Campus, National Technical University of Athens, GR-15780 Athens,
Greece
- Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven,
The Netherlands
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38
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Binder K, Milchev A. Polymer brushes on flat and curved surfaces: How computer simulations can help to test theories and to interpret experiments. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/polb.23168] [Citation(s) in RCA: 166] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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39
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Everaers R. Topological versus rheological entanglement length in primitive-path analysis protocols, tube models, and slip-link models. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:022801. [PMID: 23005812 DOI: 10.1103/physreve.86.022801] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 06/18/2012] [Indexed: 06/01/2023]
Abstract
We show that the front factor appearing in the shear modulus of a phantom network, G(ph) = (1-2/f)(ρk(B)T)/N(s), also controls the ratio of the strand length, N(s), and the number of monomers per Kuhn length of the primitive paths, N(ph)(PPKuhn), characterizing the average network conformation. In particular, N(ph)(PPKuhn) = N(s)/(1-2/f) and G(ph) = (ρk(B)T)/N(ph)(PPKuhn). Neglecting the difference between cross-links and slip-links, these results can be transferred to entangled systems and the interpretation of primitive path analysis data. In agreement with the tube model, the analogy to phantom networks suggest that the rheological entanglement length, N(e)(rheo) = (ρk(B)T)/G(e), should equal N(e)(PPKuhn). Assuming binary entanglements with f = 4 functional junctions, we expect that N(e)(rheo) should be twice as large as the topological entanglement length, N(e)(topo). These results are in good agreement with reported primitive path analysis results for model systems and a wide range of polymeric materials. Implications for tube and slip-link models are discussed.
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Derail C, Lapique F, Montfort JP. Physics of Trapped Macromolecular Chains from Surface Force Apparatus Dynamic Measurements. Macromolecules 2011. [DOI: 10.1021/ma2009029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christophe Derail
- Université de Pau et des Pays de l’Adour/CNRS IPREM UMR 5254, Equipe de Physique et Chimie des Polymères, 2 Avenue du Président Angot, 64053 Pau Cedex 09, France
| | | | - Jean-Pierre Montfort
- Université de Pau et des Pays de l’Adour/CNRS IPREM UMR 5254, Equipe de Physique et Chimie des Polymères, 2 Avenue du Président Angot, 64053 Pau Cedex 09, France
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Karayiannis NC, Kröger M. Combined molecular algorithms for the generation, equilibration and topological analysis of entangled polymers: methodology and performance. Int J Mol Sci 2009; 10:5054-5089. [PMID: 20087477 PMCID: PMC2808023 DOI: 10.3390/ijms10115054] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 11/17/2009] [Accepted: 11/20/2009] [Indexed: 12/02/2022] Open
Abstract
We review the methodology, algorithmic implementation and performance characteristics of a hierarchical modeling scheme for the generation, equilibration and topological analysis of polymer systems at various levels of molecular description: from atomistic polyethylene samples to random packings of freely-jointed chains of tangent hard spheres of uniform size. Our analysis focuses on hitherto less discussed algorithmic details of the implementation of both, the Monte Carlo (MC) procedure for the system generation and equilibration, and a postprocessing step, where we identify the underlying topological structure of the simulated systems in the form of primitive paths. In order to demonstrate our arguments, we study how molecular length and packing density (volume fraction) affect the performance of the MC scheme built around chain-connectivity altering moves. In parallel, we quantify the effect of finite system size, of polydispersity, and of the definition of the number of entanglements (and related entanglement molecular weight) on the results about the primitive path network. Along these lines we approve main concepts which had been previously proposed in the literature.
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Affiliation(s)
- Nikos Ch. Karayiannis
- Institute for Optoelectronics and Microsystems (ISOM) and ETSII, Universidad Politécnica de Madrid (UPM), José Gutiérrez Abascal 2, E-28006 Madrid, Spain
| | - Martin Kröger
- Polymer Physics, Swiss Federal Institute of Technology, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8049 Zurich, Switzerland
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Karaiskos E, Bitsanis IA, Anastasiadis SH. Monte Carlo studies of tethered chains. ACTA ACUST UNITED AC 2009. [DOI: 10.1002/polb.21878] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Hoy RS, Foteinopoulou K, Kröger M. Topological analysis of polymeric melts: chain-length effects and fast-converging estimators for entanglement length. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:031803. [PMID: 19905139 DOI: 10.1103/physreve.80.031803] [Citation(s) in RCA: 201] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 06/22/2009] [Indexed: 05/28/2023]
Abstract
Primitive path analyses of entanglements are performed over a wide range of chain lengths for both bead spring and atomistic polyethylene polymer melts. Estimators for the entanglement length N_{e} which operate on results for a single chain length N are shown to produce systematic O(1/N) errors. The mathematical roots of these errors are identified as (a) treating chain ends as entanglements and (b) neglecting non-Gaussian corrections to chain and primitive path dimensions. The prefactors for the O(1/N) errors may be large; in general their magnitude depends both on the polymer model and the method used to obtain primitive paths. We propose, derive, and test new estimators which eliminate these systematic errors using information obtainable from the variation in entanglement characteristics with chain length. The new estimators produce accurate results for N_{e} from marginally entangled systems. Formulas based on direct enumeration of entanglements appear to converge faster and are simpler to apply.
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Affiliation(s)
- Robert S Hoy
- Materials Research Laboratory, University of California, Santa Barbara, California 93106, USA.
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Response Characteristics of Thermoresponsive Polymers Using Nanomechanical Cantilever Sensors. MACROMOL CHEM PHYS 2009. [DOI: 10.1002/macp.200900081] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Ilg P, Ottinger HC, Kröger M. Systematic time-scale-bridging molecular dynamics applied to flowing polymer melts. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:011802. [PMID: 19257059 DOI: 10.1103/physreve.79.011802] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 10/30/2008] [Indexed: 05/27/2023]
Abstract
We present a thermodynamically guided, low-noise, time-scale-bridging, and pertinently efficient strategy for the dynamic simulation of microscopic models for complex fluids. The systematic coarse-graining method is exemplified for low-molecular polymeric systems subjected to homogeneous flow fields. We use established concepts of nonequilibrium thermodynamics and an alternating Monte Carlo-molecular-dynamics iteration scheme in order to obtain the model equations for the slow variables. For chosen flow situations of interest, the established model predicts structural as well as material functions beyond the regime of linear response. As a by-product, we present steady-state simulation results for polymers in general flow situations, including simple, planar, and yet unexplored equibiaxial elongation. The method is simple to implement and allows for the calculation of time-dependent behavior through quantities readily available from nonequilibrium steady states.
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Affiliation(s)
- Patrick Ilg
- Department of Materials, Polymer Physics, ETH Zürich, CH-8093 Zürich, Switzerland
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Foteinopoulou K, Karayiannis NC, Laso M, Kröger M, Mansfield ML. Universal scaling, entanglements, and knots of model chain molecules. PHYSICAL REVIEW LETTERS 2008; 101:265702. [PMID: 19437651 DOI: 10.1103/physrevlett.101.265702] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
By identifying the maximally random jammed state of freely jointed chains of tangent hard spheres we are able to determine the distinct scaling regimes characterizing the dependence of chain dimensions and topology on volume fraction. Calculated distributions of (i) the contour length of the primitive paths and (ii) the number of entanglements per chain agree remarkably well with recent theoretical predictions in all scaling regimes. Furthermore, our simulations reveal a hitherto unsuspected connection between purely intramolecular (knots) and intermolecular (entanglements) topological constraints.
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Affiliation(s)
- Katerina Foteinopoulou
- Institute for Optoelectronics and Microsystems, Universidad Politécnica de Madrid, José Gutiérrez Abascal 2, 28006 Madrid, Spain
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Foteinopoulou K, Karayiannis NC, Laso M, Kröger M. Structure, Dimensions, and Entanglement Statistics of Long Linear Polyethylene Chains. J Phys Chem B 2008; 113:442-55. [DOI: 10.1021/jp808287s] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Katerina Foteinopoulou
- Institute for Optoelectronics and Microsystems (ISOM) and ETSII, UPM, José Gutiérrez Abascal 2, E-28006 Madrid, Spain
| | - Nikos Ch. Karayiannis
- Institute for Optoelectronics and Microsystems (ISOM) and ETSII, UPM, José Gutiérrez Abascal 2, E-28006 Madrid, Spain
| | - Manuel Laso
- Institute for Optoelectronics and Microsystems (ISOM) and ETSII, UPM, José Gutiérrez Abascal 2, E-28006 Madrid, Spain
| | - Martin Kröger
- Polymer Physics, Department of Materials, ETH Zürich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
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Descas R, Sommer JU, Blumen A. Grafted Polymer Chains Interacting with Substrates: Computer Simulations and Scaling. MACROMOL THEOR SIMUL 2008. [DOI: 10.1002/mats.200800046] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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49
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Müller M, Daoulas KC. Single-chain dynamics in a homogeneous melt and a lamellar microphase: A comparison between Smart Monte Carlo dynamics, slithering-snake dynamics, and slip-link dynamics. J Chem Phys 2008; 129:164906. [DOI: 10.1063/1.2997345] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Affiliation(s)
- Jean-Pierre Montfort
- Institut Pluridisciplinaire de Recherche sur l’Environnement et les Matériaux, Université de Pau et des Pays de l’Adour, 2, avenue du Président Angot, 64013 Pau-France
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