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Liu W, Zhu Y, Li Y, Han J, Ngai T. Unveiling the structural relaxation of microgel suspensions at hydrophilic and hydrophobic interfaces. J Colloid Interface Sci 2023; 633:948-958. [PMID: 36509038 DOI: 10.1016/j.jcis.2022.11.150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/24/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022]
Abstract
HYPOTHESIS Poly(N-isopropylacrylamide) (PNIPAM) microgel particles show considerable hydrophilicity below the lower critical solution temperature (LCST) while they become hydrophobic above LCST. We hypothesize that interfacial wettability could tune particle-surface interaction and subsequent structural relaxation of microgel suspensions at interfaces during the volume phase transition. EXPERIMENTS The evanescent-wave scattering images of microgels at hydrophilic and hydrophobic interfaces are analyzed by a density-fluctuation autocorrelation function (δACF) over a wide range of particle volume fraction ϕ. The structural relaxation is characterized by the decay behavior of δACF. The scattering images in bulk are also processed as a comparison. FINDINGS A two-step relaxation decay is observed at both hydrophilic and hydrophobic interfaces. Relative to fast decay, the rate of structural relaxation in slow decay is reduced by a factor of ∼ 500 and ∼ 50 at hydrophilic and hydrophobic interfaces, respectively. The relaxation times obey divergent power-law dependences on intermediate regime of observing length scales at the two interfaces. Besides, the distribution of fluctuation for relaxation time at different local regions reveals that the structural relaxation is much more homogenous at hydrophilic interfaces than that at hydrophobic interfaces, especially at high ϕ.
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Affiliation(s)
- Wei Liu
- The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education & School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China
| | - Yuwei Zhu
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Yinan Li
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Jie Han
- School of Science and Technology, Hong Kong Metropolitan University, Homantin, Kowloon, Hong Kong, China.
| | - To Ngai
- The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education & School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China; Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
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2
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Kim YG, Thérien-Aubin H. Impact of the Solvent Quality on the Local Dynamics of Soft and Swollen Polymer Nanoparticles Functionalized with Polymer Chains. Macromolecules 2020; 53:7561-7569. [PMID: 32921813 PMCID: PMC7482391 DOI: 10.1021/acs.macromol.0c00346] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 07/28/2020] [Indexed: 12/29/2022]
Abstract
Grafting polymer chains on the surface of nanoparticles (NPs) is a strategy used to control the interaction between the NPs and their environment. The fate of the resulting particles in a given environment is strongly influenced by the solvent-polymer interaction. The solvent quality affects the behavior, conformation, and dynamics of the grafted polymer chains. However, when this polymer grafting strategy is used to functionalized polymer particles, the influence of solvent quality becomes even more complex; when the grafted polymer chains and the polymer nanoparticles are tethered together, the effect of the solvent quality on the behavior and dynamics of the system depends on the solvent interaction with both polymer components. To explore the relationship between the solvent quality and the dynamics of polymer-functionalized soft polymer NPs, we designed a system based on cross-linked polystyrene (PS) NPs grafted with a canopy of poly(methyl acrylate) (PMA). PS and PMA, two immiscible polymers, can be selectively solvated by using binary mixtures of solvents. NMR spectroscopy was used to address the effect of those selective solvents on the local mobility of the PS-PMA core-canopy NPs and revealed an interplay between the local mobility of the core and the local mobility of the canopy. A selective reduction of the solvent quality for the PMA canopy resulted in the expected reduction of the local mobility of the PMA chains, but also in the slower dynamics of the PS core. Similarly, a selective reduction of the solvent quality for the PS core resulted in a slower dynamics for both the PS core and the PMA canopy.
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Affiliation(s)
- Young-Gon Kim
- Max Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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3
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Bailey EJ, Winey KI. Dynamics of polymer segments, polymer chains, and nanoparticles in polymer nanocomposite melts: A review. Prog Polym Sci 2020. [DOI: 10.1016/j.progpolymsci.2020.101242] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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4
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Nigro V, Ruzicka B, Ruta B, Zontone F, Bertoldo M, Buratti E, Angelini R. Relaxation Dynamics, Softness, and Fragility of Microgels with Interpenetrated Polymer Networks. Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b01560] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Valentina Nigro
- Istituto dei Sistemi Complessi del Consiglio Nazionale delle Ricerche (ISC-CNR), sede Sapienza, Pz.le Aldo Moro 5, I-00185 Roma, Italy
- Dipartimento di Fisica, Sapienza Università di Roma, I-00185 Roma, Italy
| | - Barbara Ruzicka
- Istituto dei Sistemi Complessi del Consiglio Nazionale delle Ricerche (ISC-CNR), sede Sapienza, Pz.le Aldo Moro 5, I-00185 Roma, Italy
- Dipartimento di Fisica, Sapienza Università di Roma, I-00185 Roma, Italy
| | - Beatrice Ruta
- France Univ Lyon, Universitè Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, 69100 Villeurbanne, France
- ESRF The European Synchrotron, CS40220, 38043 Grenoble Cedex 9, France
| | - Federico Zontone
- ESRF The European Synchrotron, CS40220, 38043 Grenoble Cedex 9, France
| | - Monica Bertoldo
- Istituto per la Sintesi Organica e la Fotoreattività del Consiglio Nazionale delle Ricerche (ISOF-CNR), via P. Gobetti
101, 40129 Bologna, Italy
| | - Elena Buratti
- Istituto dei Sistemi Complessi del Consiglio Nazionale delle Ricerche (ISC-CNR), sede Sapienza, Pz.le Aldo Moro 5, I-00185 Roma, Italy
| | - Roberta Angelini
- Istituto dei Sistemi Complessi del Consiglio Nazionale delle Ricerche (ISC-CNR), sede Sapienza, Pz.le Aldo Moro 5, I-00185 Roma, Italy
- Dipartimento di Fisica, Sapienza Università di Roma, I-00185 Roma, Italy
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5
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Jung J, Kwon T, Oh Y, Lee YR, Sung BJ. Spatial Dependence of Non-Gaussian Diffusion of Nanoparticles in Free-Standing Thin Polymer Films. J Phys Chem B 2019; 123:9250-9259. [PMID: 31589036 DOI: 10.1021/acs.jpcb.9b07236] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The addition of nanoparticles (NPs) to a free-standing polymer film affects the properties of the film such as viscosity and glass transition temperature. Recent experiments, for example, showed that the glass transition temperature of thin polymer films was dependent on how NPs were distributed within the polymer films. However, the spatial arrangement of NPs in free-standing polymer films and its effect on the diffusion of NPs and polymers remain elusive at a molecular level. In this study, we employ generic coarse-grained models for polymers and NPs and perform extensive molecular dynamics simulations to investigate the diffusion of polymers and NPs in free-standing thin polymer films. We find that small NPs are likely to stay at the interfacial region of the polymer film, while large NPs tend to stay at the center of the film. On the other hand, as the interaction between a NP and a monomer becomes more attractive, the NP is more likely to be placed at the film center. The diffusion of monomers slows down slightly as more NPs are added to the film. Interestingly, the NP diffusion is dependent strongly on the spatial arrangement of the NPs: NPs at the interfacial region diffuse faster and undergo more non-Gaussian diffusion than NPs at the film center, which implies that the interfacial region would be more mobile and dynamically heterogeneous than the film center. We also find that the mechanism for non-Gaussian diffusion of NPs at the film center differs from that at the interfacial region and that the NP diffusion would reflect the local viscosity of the polymer films.
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Affiliation(s)
- Jinkwan Jung
- Department of Chemistry , Sogang University , Seoul 04107 , Republic of Korea
| | - Taejin Kwon
- Department of Chemistry , Sogang University , Seoul 04107 , Republic of Korea
| | - Younghoon Oh
- Department of Chemistry , Sogang University , Seoul 04107 , Republic of Korea
| | - Young-Ro Lee
- Department of Chemistry , Sogang University , Seoul 04107 , Republic of Korea
| | - Bong June Sung
- Department of Chemistry , Sogang University , Seoul 04107 , Republic of Korea
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6
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A ND, Begam N, Ibrahim M, Chandran S, Padmanabhan V, Sprung M, Basu JK. Viscosity and fragility of confined polymer nanocomposites: a tale of two interfaces. NANOSCALE 2019; 11:8546-8553. [PMID: 30990482 DOI: 10.1039/c8nr10362c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Viscosity and fragility are key parameters determining the processability and thermo-mechanical stability of glassy polymers and polymer nanocomposites (PNCs). In confined polymers, these parameters are largely dominated by the long relaxation times of the polymers adsorbed at the substrate-polymer interface. On the other hand, for polymer nanocomposites, the interface layer (IL) between the nanoparticles and the surrounding matrix chains often control not only the morphology and dispersion but also various parameters like viscosity and glass transition temperature. Confined PNCs, hence, present a unique opportunity to study the interplay of these two independent interfacial effects. Here, we report the results of X-ray scattering based dynamics measurements of PNC thin films, with a two IL width, unraveling the subtle interplay of these two interfaces on the measured viscosity and fragility. Coupled with coarse-grained molecular dynamics (MD) simulations, our experimental results demonstrate that the viscosity of the PNC films increases with both the IL width and the thickness of the polymer layer adsorbed at the substrate interface. However, while both pristine PS and PNCs with a higher IL width become stronger glasses, as estimated by their fragility, the PNC with a lower IL width shows an increase in fragility with increasing confinement. Our results suggest a novel method to control thermo-mechanical properties and stability of PNC coatings by independently controlling the two interfacial effects in athermal glassy PNCs.
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Affiliation(s)
- Nimmi Das A
- Department of Physics, Indian Institute of Science, Bangalore, 560012, India.
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7
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Song JJ, Bhattacharya R, Kim H, Chang J, Tang TY, Guo H, Ghosh SK, Yang Y, Jiang Z, Kim H, Russell TP, Arya G, Narayanan S, Sinha SK. One-Dimensional Anomalous Diffusion of Gold Nanoparticles in a Polymer Melt. PHYSICAL REVIEW LETTERS 2019; 122:107802. [PMID: 30932658 DOI: 10.1103/physrevlett.122.107802] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Indexed: 06/09/2023]
Abstract
We investigated the dynamics of polymer-grafted gold nanoparticles loaded into polymer melts using x-ray photon correlation spectroscopy. For low molecular weight host matrix polymer chains, normal isotropic diffusion of the gold nanoparticles is observed. For larger molecular weights, anomalous diffusion of the nanoparticles is observed that can be described by ballistic motion and generalized Lévy walks, similar to those often used to discuss the dynamics of jammed systems. Under certain annealing conditions, the diffusion is one-dimensional and related to the direction of heat flow during annealing and is associated with an dynamic alignment of the host polymer chains. Molecular dynamics simulations of a single gold nanoparticle diffusing in a partially aligned polymer network semiquantitatively reproduce the experimental results to a remarkable degree. The results help to showcase how nanoparticles can under certain circumstances move rapidly in polymer networks.
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Affiliation(s)
- Jing-Jin Song
- Department of Materials Science & Engineering, University of California San Diego, 9500 Gilman Dr. La Jolla, California 92093, USA
| | - Rupak Bhattacharya
- Department of Physics, University of California San Diego, 9500 Gilman Dr. La Jolla, California 92093, USA
| | - Hyunki Kim
- Polymer Science and Engineering Department, University of Massachusetts Amherst, Amherst Massachusetts 01003, USA
| | - Jooyoung Chang
- Polymer Science and Engineering Department, University of Massachusetts Amherst, Amherst Massachusetts 01003, USA
| | - Tsung-Yeh Tang
- Department of NanoEngineering, University of California San Diego, 9500 Gilman Dr. La Jolla, California 92093, USA
| | - Hongyu Guo
- National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, Maryland 20899-6102, USA
| | - Sajal K Ghosh
- Department of Physics, University of California San Diego, 9500 Gilman Dr. La Jolla, California 92093, USA
| | - Yi Yang
- Department of Physics, University of California San Diego, 9500 Gilman Dr. La Jolla, California 92093, USA
| | - Zhang Jiang
- Advanced Photon Source, Argonne National Laboratory, 9700 Cass Ave, Lemont, Illinois 60439, USA
| | - Hyeyoung Kim
- Polymer Science and Engineering Department, University of Massachusetts Amherst, Amherst Massachusetts 01003, USA
| | - Thomas P Russell
- Polymer Science and Engineering Department, University of Massachusetts Amherst, Amherst Massachusetts 01003, USA
| | - Gaurav Arya
- Department of NanoEngineering, University of California San Diego, 9500 Gilman Dr. La Jolla, California 92093, USA
| | - Suresh Narayanan
- Advanced Photon Source, Argonne National Laboratory, 9700 Cass Ave, Lemont, Illinois 60439, USA
| | - Sunil K Sinha
- Department of Physics, University of California San Diego, 9500 Gilman Dr. La Jolla, California 92093, USA
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8
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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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9
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Balitska V, Shpotyuk O, Brunner M, Hadzaman I. Stretched-to-compressed-exponential crossover observed in the electrical degradation kinetics of some spinel-metallic screen-printed structures. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2017.12.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Shpotyuk O, Brunner M, Hadzaman I, Balitska V, Klym H. Analytical Description of Degradation-Relaxation Transformations in Nanoinhomogeneous Spinel Ceramics. NANOSCALE RESEARCH LETTERS 2016; 11:499. [PMID: 27844462 PMCID: PMC5108734 DOI: 10.1186/s11671-016-1722-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 11/04/2016] [Indexed: 06/06/2023]
Abstract
Mathematical models of degradation-relaxation kinetics are considered for jammed thick-film systems composed of screen-printed spinel Cu0.1Ni0.1Co1.6Mn1.2O4 and conductive Ag or Ag-Pd alloys. Structurally intrinsic nanoinhomogeneous ceramics due to Ag and Ag-Pd diffusing agents embedded in a spinel phase environment are shown to define governing kinetics of thermally induced degradation under 170 °C obeying an obvious non-exponential behavior in a negative relative resistance drift. The characteristic stretched-to-compressed exponential crossover is detected for degradation-relaxation kinetics in thick-film systems with conductive contacts made of Ag-Pd and Ag alloys. Under essential migration of a conductive phase, Ag penetrates thick-film spinel ceramics via a considerable two-step diffusing process.
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Affiliation(s)
- O Shpotyuk
- Jan Dlugosz University in Czestochowa, 13/15, Armii Krajowej str., 42200, Czestochowa, Poland.
- Vlokh Institute of Physical Optics, 23, Dragomanov str., Lviv, 79005, Ukraine.
| | - M Brunner
- Technische Hochschule Köln/University of Technology, Arts, Sciences, 2, Betzdorfer Strasse, Köln, 50679, Germany
| | - I Hadzaman
- Drohobych Ivan Franko State Pedagogical University, 24, I. Franko str., Drohobych, 82100, Ukraine
| | - V Balitska
- Lviv State University of Life Safety, 35, Kleparivska str., Lviv, 79007, Ukraine
| | - H Klym
- Lviv Polytechnic National University, 12, Bandera str., Lviv, 79013, Ukraine
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11
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Chandran S, Saw S, Kandar AK, Dasgupta C, Sprung M, Basu JK. Suspensions of polymer-grafted nanoparticles with added polymers—Structure and effective pair-interactions. J Chem Phys 2015; 143:084902. [DOI: 10.1063/1.4929438] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Sivasurender Chandran
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
- Institute of Physics, Albert–Ludwigs University of Freiburg, 79104 Freiburg, Germany
| | - Shibu Saw
- Centre for Condensed Matter Theory, Indian Institute of Science, Bangalore 560012, India
- School of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - A. K. Kandar
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - C. Dasgupta
- Centre for Condensed Matter Theory, Indian Institute of Science, Bangalore 560012, India
| | - M. Sprung
- Deutsches Elektronen Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - J. K. Basu
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
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12
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Structure and dynamics of polymer nanocomposites studied by X-ray and neutron scattering techniques. Curr Opin Colloid Interface Sci 2015. [DOI: 10.1016/j.cocis.2015.10.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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13
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Begam N, Chandran S, Biswas N, Basu JK. Kinetics of dispersion of nanoparticles in thin polymer films at high temperature. SOFT MATTER 2015; 11:1165-1173. [PMID: 25560367 DOI: 10.1039/c4sm02383h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the first detailed study of the kinetics of dispersion of nanoparticles in thin polymer films using temperature dependent in situ X-ray scattering measurements. We show a comparably enhanced dispersion at higher temperatures for systems which are otherwise phase segregated at room temperature. Detailed analysis of the time dependent X-ray reflectivity and diffuse scattering data allows us to explore the out-of-plane and in-plane mobility of the nanoparticles in the polymer films. While the out-of-plane motion is diffusive with a diffusion coefficient almost two orders of magnitude lower than that expected in bulk polymer, the in-plane one is found to be super-diffusive resulting in significantly larger in-plane displacement at similar time scales. We discuss the origin of the observed highly anisotropic motion of nanoparticles due to their slaved motion with respect to the anisotropic chain orientation and consequent diffusivity anisotropy of matrix chains. We also suggest strategies to utilize these observations to kinetically improve dispersion in otherwise thermodynamically segregated polymer nanocomposite films.
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Affiliation(s)
- Nafisa Begam
- Department of Physics, Indian Institute of Science, Bangalore, 560 012, India.
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14
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Yang J, Han CR, Zhang XM, Xu F, Sun RC. Cellulose Nanocrystals Mechanical Reinforcement in Composite Hydrogels with Multiple Cross-Links: Correlations between Dissipation Properties and Deformation Mechanisms. Macromolecules 2014. [DOI: 10.1021/ma500729q] [Citation(s) in RCA: 154] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Jun Yang
- Beijing
Key Laboratory of
Lignocellulosic Chemistry, College of Materials Science and Technology, Beijing Forestry University, Beijing 100083, China
| | - Chun-Rui Han
- Beijing
Key Laboratory of
Lignocellulosic Chemistry, College of Materials Science and Technology, Beijing Forestry University, Beijing 100083, China
| | - Xue-Ming Zhang
- Beijing
Key Laboratory of
Lignocellulosic Chemistry, College of Materials Science and Technology, Beijing Forestry University, Beijing 100083, China
| | - Feng Xu
- Beijing
Key Laboratory of
Lignocellulosic Chemistry, College of Materials Science and Technology, Beijing Forestry University, Beijing 100083, China
| | - Run-Cang Sun
- Beijing
Key Laboratory of
Lignocellulosic Chemistry, College of Materials Science and Technology, Beijing Forestry University, Beijing 100083, China
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15
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Li Y, Kröger M, Liu WK. Dynamic structure of unentangled polymer chains in the vicinity of non-attractive nanoparticles. SOFT MATTER 2014; 10:1723-1737. [PMID: 24651875 DOI: 10.1039/c3sm51564h] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Using coarse-grained molecular dynamics simulation, we study the motion of unentangled polymer chains dynamically confined by non-attractive nanoparticles (NPs). Both normal mode and dynamic structure factor S(q, t) analysis are adopted to analyze chain's dynamics. Relaxation behaviors of chains are found to be significantly slowed down by NPs. The relaxation times of chain's normal modes are monotonically increasing with the NP volume fraction ϕ. At the same time, chains' dynamics are becoming non-Gaussian. Inspection of S(q, t) reveals that chain's dynamics can be attributed to two 'phases', a bulk polymer phase and a confined polymer phase between NPs. The dynamics of a confined polymer is slower than that of a bulk polymer, while still exhibiting high mobility. The amount of the bulk polymer phase is found to exponentially decay with increasing ϕ. With this figure at hand, we establish a simple relationship between NP and confined/interphase polymer volume fractions. This work seems to provide the first quantitative prediction on the relationship between NP and confined/interphase polymer volume fractions.
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Affiliation(s)
- Ying Li
- Department of Mechanical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-0311, USA.
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16
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Chandran S, C. K. S, Kandar AK, Basu JK, Narayanan S, Sandy A. Re-entrant behavior in dynamics of binary mixtures of soft hybrid nanocolloids and homopolymers. J Chem Phys 2011; 135:134901. [DOI: 10.1063/1.3644930] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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17
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Srivastava S, Chandran S, Kandar AK, Sarika CK, Basu JK, Narayanan S, Sandy A. Communication: Unusual dynamics of hybrid nanoparticles and their binary mixtures. J Chem Phys 2010; 133:151105. [DOI: 10.1063/1.3495480] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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18
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Feng Y, Goree J, Liu B. Identifying anomalous diffusion and melting in dusty plasmas. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 82:036403. [PMID: 21230192 DOI: 10.1103/physreve.82.036403] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Revised: 08/02/2010] [Indexed: 05/30/2023]
Abstract
Anomalous diffusion in liquids and the solid-liquid phase transition (melting) are studied in two-dimensional Yukawa systems. The self-intermediate scattering function (self-ISF), calculated from simulation data, exhibits a temporal decay, or relaxation, with a characteristic relaxation time. This decay is found to be useful for distinguishing normal and anomalous diffusion in a liquid, and for identifying the solid-liquid phase transition. For liquids, a scaling of the relaxation time with length scale is found. For the solid-liquid phase transition, the shape of the self-ISF curve is found to be a sensitive indicator of phase. Friction has a significant effect on the timing of relaxation, but not the melting point.
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Affiliation(s)
- Yan Feng
- Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242, USA.
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Goswami M, Sumpter BG. Anomalous chain diffusion in polymer nanocomposites for varying polymer-filler interaction strengths. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:041801. [PMID: 20481738 DOI: 10.1103/physreve.81.041801] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 12/17/2009] [Indexed: 05/29/2023]
Abstract
Anomalous diffusion of polymer chains in a polymer nanocomposite melt is investigated for different polymer-nanoparticle interaction strengths using stochastic molecular dynamics simulations. For spherical nanoparticles dispersed in a polymer matrix the results indicate that the chain motion exhibits three distinct regions of diffusion, the Rouse-like motion, an intermediate subdiffusive regime followed by a normal Fickian diffusion. The motion of the chain end monomers shows a scaling that can be attributed to the formation of strong "networklike" structures, which have been seen in a variety of polymer nanocomposite systems. Irrespective of the polymer-particle interaction strengths, these three regimes seem to be present with small deviations. Further investigation on dynamic structure factor shows that the deviations simply exist due to the presence of strong enthalpic interactions between the monomers with the nanoparticles, albeit preserving the anomaly in the chain diffusion. The time-temperature superposition principle is also tested for this system and shows a striking resemblance with systems near glass transition and biological systems with molecular crowding. The universality class of the problem can be enormously important in understanding materials with strong affinity to form either a glass, a gel or networklike structures.
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Affiliation(s)
- Monojoy Goswami
- Computational Chemical Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
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20
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Kandar AK, Srivastava S, Basu JK, Mukhopadhyay MK, Seifert S, Narayanan S. Unusual dynamical arrest in polymer grafted nanoparticles. J Chem Phys 2009; 130:121102. [DOI: 10.1063/1.3090484] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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