1
|
Siachouli P, Karadima KS, Mavrantzas VG, Pandis SN. The effect of functional groups on the glass transition temperature of atmospheric organic compounds: a molecular dynamics study. SOFT MATTER 2024; 20:4783-4794. [PMID: 38847330 DOI: 10.1039/d4sm00405a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Organic compounds constitute a substantial part of atmospheric particulate matter not only in terms of mass concentration but also in terms of distinct functional groups. The glass transition temperature provides an indirect way to investigate the phase state of the organic compounds, playing a crucial role in understanding their behavior and influence on aerosol processes. Molecular dynamics (MD) simulations were implemented here to predict the glass transition temperature (Tg) of atmospherically relevant organic compounds as well as the influence of their functional groups and length of their carbon chain. The cooling step used in the simulations was chosen to be neither too low (to supress crystallization) nor too high (to avoid Tg overprediction). According to the MD simulations, the predicted Tg is sensitive to the functional groups as follows: carboxylic acid (-COOH) > hydroxyl (-OH) and (-COOH) > carbonyls (-CO). Increasing the number of carbon atoms leads to higher Tg for the linearly structured compounds. Linear compounds with lower molecular weight were found to exhibit a lower Tg. No clear correlation between O : C and Tg was observed. The architecture of the carbon chain (linear, or branched, or ring) was also found to impact the glass transition temperature. Compounds containing a non-aromatic carbon ring are characterized by a higher Tg compared to linear and branched ones with the same number of carbon atoms.
Collapse
Affiliation(s)
- Panagiota Siachouli
- Department of Chemical Engineering, University of Patras, Patras, GR 26504, Greece.
- Institute of Chemical Engineering Sciences (ICE-HT/FORTH), Patras, GR 26504, Greece
| | - Katerina S Karadima
- Department of Chemical Engineering, University of Patras, Patras, GR 26504, Greece.
- Institute of Chemical Engineering Sciences (ICE-HT/FORTH), Patras, GR 26504, Greece
| | - Vlasis G Mavrantzas
- Department of Chemical Engineering, University of Patras, Patras, GR 26504, Greece.
- Institute of Chemical Engineering Sciences (ICE-HT/FORTH), Patras, GR 26504, Greece
- Particle Technology Laboratory, Department of Mechanical and Process Engineering, ETH Zürich, CH-8092 Zürich, Switzerland
| | - Spyros N Pandis
- Department of Chemical Engineering, University of Patras, Patras, GR 26504, Greece.
- Institute of Chemical Engineering Sciences (ICE-HT/FORTH), Patras, GR 26504, Greece
| |
Collapse
|
2
|
Reda H, Tanis I, Harmandaris V. Distribution of Mechanical Properties in Poly(ethylene oxide)/silica Nanocomposites via Atomistic Simulations: From the Glassy to the Liquid State. Macromolecules 2024; 57:3967-3984. [PMID: 38911610 PMCID: PMC11190983 DOI: 10.1021/acs.macromol.4c00537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/06/2024] [Accepted: 04/16/2024] [Indexed: 06/25/2024]
Abstract
Polymer nanocomposites exhibit a heterogeneous mechanical behavior that is strongly dependent on the interaction between the polymer matrix and the nanofiller. Here, we provide a detailed investigation of the mechanical response of model polymer nanocomposites under deformation, across a range of temperatures, from the glassy regime to the liquid one, via atomistic molecular dynamics simulations. We study the poly(ethylene oxide) matrix with silica nanoparticles (PEO/SiO2) as a model polymer nanocomposite system with attractive polymer/nanofiller interactions. Probing the properties of polymer chains at the molecular level reveals that the effective mass density of the matrix and interphase regions changes during deformation. This decrease in density is much more pronounced in the glassy state. We focus on factors that govern the mechanical response of PEO/SiO2 systems by investigating the distribution of the (local) mechanical properties, focusing on the polymer/nanofiller interphase and matrix regions. As expected when heating the system, a decrease in Young's modulus is observed, accompanied by an increase in Poisson's ratio. The observed differences regarding the rigidity between the interphase and the matrix region decrease as the temperature rises; at temperatures well above the glass-transition temperature, the rigidity of the interphase approaches the matrix one. To describe the nonlinear viscoelastic behavior of polymer chains, the elastic modulus of the PEO/SiO2 systems is further calculated as a function of the strain for the entire nanocomposite, as well as the interphase and matrix regions. The elastic modulus drops dramatically with increasing strain for both the matrix and the interphase, especially in the small-deformation regime. We also shed light on characteristic structural and dynamic attributes during deformation. Specifically, we examine the rearrangement behavior as well as the segmental and center-of-mass dynamics of polymer chains during deformation by probing the mobility of polymer chains in both axial and radial motions under deformation. The behavior of the polymer motion in the axial direction is dominated by the deformation, particularly at the interphase, whereas a more pronounced effect of the temperature is observed in the radial directions for both the interphase and matrix regions.
Collapse
Affiliation(s)
- Hilal Reda
- Computation-based
Science and Technology Research Center, The Cyprus Institute, Nicosia 2121, Cyprus
| | - Ioannis Tanis
- Computation-based
Science and Technology Research Center, The Cyprus Institute, Nicosia 2121, Cyprus
| | - Vagelis Harmandaris
- Computation-based
Science and Technology Research Center, The Cyprus Institute, Nicosia 2121, Cyprus
- Department
of Mathematics and Applied Mathematics, University of Crete, Heraklion GR-71110, Greece
- Institute
of Applied and Computational Mathematics, Foundation for Research and Technology - Hellas, Heraklion GR-71110, Greece
| |
Collapse
|
3
|
Shen J, Li X, Li P, Shentu B. Structural and dynamical properties of thermoplastic polyurethane/fullerene nanocomposites: a molecular dynamics simulations study. Phys Chem Chem Phys 2023; 25:27352-27363. [PMID: 37791853 DOI: 10.1039/d3cp03809b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
In this work, the structural and dynamical properties of thermoplastic polyurethane (TPU)/fullerene (C60) nanocomposites are investigated using atomistic molecular dynamics simulations, focusing on the glass transition, thermal expansion, polymer mobility, polymer-C60 interactions, and diffusion behavior of C60. The results show a slight increase in the glass transition temperature (Tg) with increasing C60 weight fraction (wt%), attributed to hindered polymer dynamics, and a remarkable reduction in the coefficient of thermal expansion above Tg. Results of the mean squared displacement and the time decay of bond-reorientation autocorrelation indicate that the mobility of TPU hard segments is more restricted than that of soft segments, owing to the electrostatic attractions and the π-π stacking between isocyanate groups and C60 molecules. Analysis of TPU-C60 interaction energy reveals that the electrostatic interactions are weakened with an increase in the C60 wt%, while the van der Waals contributions become more significant due to the TPU-C60 interfacial characteristics. Further analysis shows that the translational and rotational diffusion of C60 are both increasingly suppressed with the increase of C60 wt%, indicating a violation of Stokes-Einstein (SE) and Stokes-Einstein-Debye (SED) relations, presumably due to the polymer chain-mediated hydrodynamic interactions arising from chain bridges between neighboring C60 particles. This is highlighted by a stronger decoupling of translational-rotational diffusion and a lower ratio of translational-rotational diffusion coefficient (DT/DR) with increasing C60 wt%. This work elucidates an atomistic understanding of the structure and properties of polymer/C60 nanocomposites.
Collapse
Affiliation(s)
- Jianxiang Shen
- State Key Lab of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China.
- Department of Polymer Science and Technology, Jiaxing University, Jiaxing 314001, China
- Zhejiang Double Arrow Rubber Co., Ltd., Tongxiang 314513, China
| | - Xue Li
- School of Advanced Materials Engineering, Jiaxing Nanhu University, Jiaxing 314001, China.
| | - Ping Li
- Department of Polymer Science and Technology, Jiaxing University, Jiaxing 314001, China
| | - Baoqing Shentu
- State Key Lab of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China.
| |
Collapse
|
4
|
Papchenko K, Ricci E, De Angelis MG. Modelling across Multiple Scales to Design Biopolymer Membranes for Sustainable Gas Separations: 1—Atomistic Approach. Polymers (Basel) 2023; 15:polym15071805. [PMID: 37050418 PMCID: PMC10097394 DOI: 10.3390/polym15071805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/28/2023] [Accepted: 04/04/2023] [Indexed: 04/08/2023] Open
Abstract
In this work, we assessed the CO2 and CH4 sorption and transport in copolymers of 3-hydroxybutyrate and 3-hydroxyvalerate (PHBV), which showed good CO2 capture potential in our previous papers, thanks to their good solubility–selectivity, and are potential biodegradable alternatives to standard membrane-separation materials. Experimental tests were carried out on a commercial material containing 8% of 3-hydroxyvalerate (HV), while molecular modelling was used to screen the performance of the copolymers across the entire composition range by simulating structures with 0%, 8%, 60%, and 100% HV, with the aim to provide a guide for the selection of the membrane material. The polymers were simulated using molecular dynamics (MD) models and validated against experimental density, solubility parameters, and X-ray diffraction. The CO2/CH4 solubility–selectivity predicted by the Widom insertion method is in good agreement with experimental data, while the diffusivity–selectivity obtained via mean square displacement is somewhat overestimated. Overall, simulations indicate promising behaviour for the homopolymer containing 100% of HV. In part 2 of this series of papers, we will investigate the same biomaterials using a macroscopic model for polymers and compare the accuracy and performance of the two approaches.
Collapse
Affiliation(s)
- Kseniya Papchenko
- Institute for Materials and Processes, School of Engineering, University of Edinburgh, Sanderson Building, Robert Stevenson Road, Edinburgh EH9 3FB, UK
| | - Eleonora Ricci
- Department of Civil, Chemical Environmental and Materials Engineering, DICAM, University of Bologna, Via Terracini 28, 40131 Bologna, Italy
| | - Maria Grazia De Angelis
- Institute for Materials and Processes, School of Engineering, University of Edinburgh, Sanderson Building, Robert Stevenson Road, Edinburgh EH9 3FB, UK
- National Interuniversity Consortium of Materials Science and Technology INSTM, Via G. Giusti, 58100 Firenze, Italy
| |
Collapse
|
5
|
Power AJ, Papananou H, Rissanou AN, Labardi M, Chrissopoulou K, Harmandaris V, Anastasiadis SH. Dynamics of Polymer Chains in Poly(ethylene oxide)/Silica Nanocomposites via a Combined Computational and Experimental Approach. J Phys Chem B 2022; 126:7745-7760. [PMID: 36136347 DOI: 10.1021/acs.jpcb.2c04325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dynamics of polymer chains in poly(ethylene oxide)/silica (PEO/SiO2) nanoparticle nanohybrids have been investigated via a combined computational and experimental approach involving atomistic molecular dynamics simulations and dielectric relaxation spectroscopy (DRS) measurements. The complementarity of the approaches allows us to study systems with different polymer molecular weights, nanoparticle radii, and compositions across a broad range of temperatures. We study the effects of spatial confinement, which is induced by the nanoparticles, and chain adsorption on the polymer's structure and dynamics. The investigation of the static properties of the nanocomposites via detailed atomistic simulations revealed a heterogeneous polymer density layer at the vicinity of the PEO/SiO2 interface that exhibited an intense maximum close to the inorganic surface, whereas the bulk density was reached for distances ∼1-1.2 nm away from the nanoparticle. For small volume fractions of nanoparticles, the polymer dynamics, probed by the atomistic simulations of low-molecular-weight chains at high temperatures, are consistent with the presence of a thin adsorbed layer that exhibits slow dynamics, with the dynamics far away from the nanoparticle being similar to those in the bulk. However, for high volume fractions of nanoparticles (strong confinement), the dynamics of all polymer chains were predicted slower than that in the bulk. On the other hand, similar dynamics were found experimentally for both the local β-process and the segmental dynamics for high-molecular-weight systems measured at temperatures below the melting temperature of the polymer, which were probed by DRS. These differences can be attributed to various parameters, including systems of different molecular weights and nanoparticle states of dispersion, the different temperature range studied by the different methods, the potential presence of a reduced-mobility PEO/SiO2 interfacial layer that does not contribute to the dielectric spectrum, and the presence of amorphous-crystalline interfaces in the experimental samples that may lead to a different dynamical behaviors of the PEO chains.
Collapse
Affiliation(s)
- Albert J Power
- Department of Mathematics and Applied Mathematics, University of Crete, Heraklion 70013, Greece.,Institute of Applied and Computational Mathematics, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece
| | - Hellen Papananou
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece.,Department of Chemistry, University of Crete, P.O. Box 2208, Heraklion 71003, Greece
| | - Anastassia N Rissanou
- Department of Mathematics and Applied Mathematics, University of Crete, Heraklion 70013, Greece.,Computation-Based Science and Technology Research Center, The Cyprus Institute, Nicosia 2121, Cyprus
| | - Massimiliano Labardi
- CNR-IPCF, c/o Physics Department, University of Pisa, Largo Pontecorvo 3, Pisa 56127, Italy
| | - Kiriaki Chrissopoulou
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece
| | - Vagelis Harmandaris
- Department of Mathematics and Applied Mathematics, University of Crete, Heraklion 70013, Greece.,Institute of Applied and Computational Mathematics, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece.,Computation-Based Science and Technology Research Center, The Cyprus Institute, Nicosia 2121, Cyprus
| | - Spiros H Anastasiadis
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece.,Department of Chemistry, University of Crete, P.O. Box 2208, Heraklion 71003, Greece
| |
Collapse
|
6
|
Vogiatzis GG, van Breemen LCA, Hütter M. Response of Elementary Structural Transitions in Glassy Atactic Polystyrene to Temperature and Deformation. J Phys Chem B 2022; 126:7731-7744. [PMID: 36129780 PMCID: PMC9549470 DOI: 10.1021/acs.jpcb.2c04199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effects of temperature, pressure, and imposed strain on the structural transition pathways of glassy atactic polystyrene (aPS) are studied for a wide range of conditions. By employing an atomistic description of the system, we systematically explore its free energy landscape, emphasizing connections between local free energy minima. A triplet of two minima connected to each other via a first-order saddle point provides the full description of each elementary structural relaxation event. The basis of the analysis is the potential energy landscape (PEL), where efficient methods for finding saddle points and exploring transition pathways have been developed. We then translate the stationary points of the PEL to stationary points of the proper free energy landscape that obeys the macroscopically imposed constraints (either stress- or strain-controlled). By changing the temperature under isobaric conditions (i.e., Gibbs energy landscape), we probe the temperature dependence of the transition rates of the subglass relaxations of aPS, thus obtaining their activation energies by fitting to the Arrhenius equation. The imposition of different strain levels under isothermic conditions allows us to estimate the apparent activation volume of every elementary transition. Our findings are in good agreement with experimental observations for the same system, indicating that both length- and time-scales of the structural transitions of glassy aPS can be obtained by proper free energy minimization of atomistically detailed configurations.
Collapse
Affiliation(s)
- Georgios G Vogiatzis
- Polymer Technology, Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.,Dutch Polymer Institute, P.O. Box 902, 5600 AX Eindhoven, The Netherlands
| | - Lambèrt C A van Breemen
- Polymer Technology, Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Markus Hütter
- Polymer Technology, Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| |
Collapse
|
7
|
Reda H, Chazirakis A, Power AJ, Harmandaris V. Mechanical Behavior of Polymer Nanocomposites via Atomistic Simulations: Conformational Heterogeneity and the Role of Strain Rate. J Phys Chem B 2022; 126:7429-7444. [DOI: 10.1021/acs.jpcb.2c04597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hilal Reda
- Computation-based Science and Technology Research Center, The Cyprus Institute, Aglantzia, 2121, Nicosia, Cyprus
| | - Anthony Chazirakis
- Institute of Applied and Computational Mathematics, Foundation for Research and Technology - Hellas, Heraklion GR-71110, Greece
| | - Albert J. Power
- Institute of Applied and Computational Mathematics, Foundation for Research and Technology - Hellas, Heraklion GR-71110, Greece
- Department of Mathematics and Applied Mathematics, University of Crete, Heraklion GR-71110, Greece
| | - Vagelis Harmandaris
- Institute of Applied and Computational Mathematics, Foundation for Research and Technology - Hellas, Heraklion GR-71110, Greece
- Department of Mathematics and Applied Mathematics, University of Crete, Heraklion GR-71110, Greece
- Computation-based Science and Technology Research Center, The Cyprus Institute, Nicosia 2121, Cyprus
| |
Collapse
|
8
|
Li C, Wei H, Zhan H, Bai J, Kou L, Gu Y. Tensile Performance of Polymer Nanocomposites with Randomly Dispersed Carbon Nanothreads. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chengkai Li
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
| | - Hanqing Wei
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
| | - Haifei Zhan
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
- Department of Civil Engineering, Zhejiang University, Hangzhou 310058, China
- Center for Materials Science, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
| | - Jingshuai Bai
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
| | - Liangzhi Kou
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
- Center for Materials Science, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
| | - Yuantong Gu
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
- Center for Materials Science, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
| |
Collapse
|
9
|
Skountzos EN, Karadima KS, Mavrantzas VG. Structure and Dynamics of Highly Attractive Polymer Nanocomposites in the Semi-Dilute Regime: The Role of Interfacial Domains and Bridging Chains. Polymers (Basel) 2021; 13:2749. [PMID: 34451287 PMCID: PMC8400934 DOI: 10.3390/polym13162749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/10/2021] [Accepted: 08/10/2021] [Indexed: 11/17/2022] Open
Abstract
Detailed molecular dynamics (MD) simulations are employed to study how the presence of adsorbed domains and nanoparticle bridging chains affect the structural, conformational, thermodynamic, and dynamic properties of attractive polymer nanocomposite melts in the semi-dilute regime. As a model system we have chosen an unentangled poly(ethylene glycol) (PEG) matrix containing amorphous spherical silica nanoparticles with different diameters and at different concentrations. Emphasis is placed on properties such as the polymer mass density profile around nanoparticles, the compressibility of the system, the mean squared end-to-end distance of PEG chains, their orientational and diffusive dynamics, the single chain form factor, and the scattering functions. Our analysis reveals a significant impact of the adsorbed, interfacial polymer on the microscopic dynamic and conformational properties of the nanocomposite, especially under conditions favoring higher surface-to-volume ratios (e.g., for small nanoparticle sizes at fixed nanoparticle loading, or for higher silica concentrations). Simultaneously, adsorbed polymer chains adopt graft-like conformations, a feature that allows them to considerably extend away from the nanoparticle surface to form bridges with other nanoparticles. These bridges drive the formation of a nanoparticle network whose strength (number of tie chains per nanoparticle) increases substantially with increasing concentration of the polymer matrix in nanoparticles, or with decreasing nanoparticle size at fixed nanoparticle concentration. The presence of hydroxyl groups at the ends of PEG chains plays a key role in the formation of the network. If hydroxyl groups are substituted by methoxy ones, the simulations reveal that the number of bridging chains per nanoparticle decreases dramatically, thus the network formed is less dense and less strong mechanically, and has a smaller impact on the properties of the nanocomposite. Our simulations predict further that the isothermal compressibility and thermal expansion coefficient of PEG-silica nanocomposites are significantly lower than those of pure PEG, with their values decreasing practically linear with increasing concentration of the nanocomposite in nanoparticles.
Collapse
Affiliation(s)
- Emmanuel N. Skountzos
- Department of Chemical Engineering, University of Patras and FORTH-ICE/HT, GR 26504 Patras, Greece; (E.N.S.); (K.S.K.)
| | - Katerina S. Karadima
- Department of Chemical Engineering, University of Patras and FORTH-ICE/HT, GR 26504 Patras, Greece; (E.N.S.); (K.S.K.)
| | - Vlasis G. Mavrantzas
- Department of Chemical Engineering, University of Patras and FORTH-ICE/HT, GR 26504 Patras, Greece; (E.N.S.); (K.S.K.)
- Particle Technology Laboratory, Department of Mechanical and Process Engineering, ETH Zürich, CH 8092 Zürich, Switzerland
| |
Collapse
|
10
|
Vogiatzis GG, van Breemen LCA, Hütter M. Structural Transitions in Glassy Atactic Polystyrene Using Transition-State Theory. J Phys Chem B 2021; 125:7273-7289. [PMID: 34161106 PMCID: PMC8279558 DOI: 10.1021/acs.jpcb.1c02618] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
![]()
Transition pathways
on the energy landscape of atactic polystyrene
(aPS) glassy specimens are probed below its glass-transition temperature.
Each of these transitions is considered an elementary structural relaxation
event, whose corresponding rate constant is calculated by applying
multidimensional transition-state theory. Initially, a wide spectrum
of first-order saddle points surrounding local minima on the energy
landscape is discovered by a stabilized hybrid eigenmode-following
method. Then, (minimal-energy) “reaction paths” to the
adjacent minima are constructed by a quadratic descent method. The
heights of the free energy, the potential energy, and the entropy
barriers are estimated for every connected triplet of transition state
and minima. The resulting distribution of free energy barriers is
asymmetric and extremely broad, extending to very high barrier heights
(over 50 kBT); the corresponding
distribution of rate constants extends over 30 orders of magnitude,
with well-defined peaks at the time scales corresponding to the subglass
relaxations of polystyrene. Analysis of the curvature along the reaction
paths reveals a multitude of different rearrangement mechanisms; some
of them bearing multiple distinct phases. Finally, connections to
theoretical models of the glass phenomenology allows for the prediction,
based on first-principles, of the “ideal” glass-transition
temperature entering the Vogel–Fulcher–Tammann (VFT)
equation describing the super-Arrhenius temperature dependence of
glassy dynamics. Our predictions of the time scales of the subglass
relaxations and the VFT temperature are in favorable agreement with
available experimental literature data for systems of similar molecular
weight under the same conditions.
Collapse
Affiliation(s)
- Georgios G Vogiatzis
- Polymer Technology, Department of Mechanical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.,Dutch Polymer Institute, PO Box 902, 5600 AX Eindhoven, The Netherlands
| | - Lambèrt C A van Breemen
- Polymer Technology, Department of Mechanical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - Markus Hütter
- Polymer Technology, Department of Mechanical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| |
Collapse
|
11
|
|
12
|
Sgouros AP, Tsagkalakis DS, Theodorou DN. Effect of Surface Nanopatterning on Slip: The Case of Couette Flow of Long-Chain Polyethylene Melt Flowing Past Gold Surfaces. J Phys Chem B 2021; 125:6681-6696. [PMID: 34126736 DOI: 10.1021/acs.jpcb.1c02546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The manifestation of slip during flow of a polymer melt past a solid surface depends on several parameters, such as film thickness, the strength of polymer-solid interactions compared to the cohesive energy of the polymer, and the roughness of the surface. Understanding the role of these molecular aspects for slip is crucial in microfluidics, friction-tuning, polymer extrusion, and nanocomposites applications. The present article investigates the effect of surface nanopatterning on slip, via Couette-flow simulations of long chain polyethylene melts past nanopatterned gold surfaces. Slip is quantified in terms of the true and effective slip velocity, and the slip length. When polymer chains are adsorbed to surfaces with periodic features (e.g., crystal planes), they develop preferential ordering in a way that enables them to minimize their free energy. The orientation of a chain is affected by that of its neighbors; thus, when several chains come together, they are prone to form regions with crystal-like orientation. We show that, in some cases, the introduction of nanopatterns on the surface can perturb and induce reorganization of these regions, and in turn affect slip. The nanopatterns are realized as periodic defect stripes of variable width, depth, areal density, and orientation angle. In situations in which the width of the defects becomes comparable to the diameter of individual chain backbones, slip is minimized (stick conditions). Cutting the nanopatterns in low symmetry directions can affect the quality of their edges and lead to enhanced friction. To characterize these edges we have devised a scheme for the quantification of the mean square roughness and mean position of the surface, which is general and applicable in 2 and 3 dimensions for any kind of material, either crystalline of amorphous. Applying the patterns on the opposing solid surfaces in a symmetric or antisymmetric manner has a profound effect on flow. We show that the application of nanopatterns in symmetric configurations generates zero net flow and induces additional shear along directions normal to the direction of the flow. The application of symmetry-breaking configurations can guide flow toward preferential directions, a result with possible applications in microfluidic devices.
Collapse
Affiliation(s)
- A P Sgouros
- School of Chemical Engineering, National Technical University of Athens (NTUA), Athens, GR-15780, Greece
| | - D S Tsagkalakis
- School of Chemical Engineering, National Technical University of Athens (NTUA), Athens, GR-15780, Greece
| | - D N Theodorou
- School of Chemical Engineering, National Technical University of Athens (NTUA), Athens, GR-15780, Greece
| |
Collapse
|
13
|
Mols RHM, Vogiatzis GG, van Breemen LCA, Hütter M. Microscopic Carriers of Plasticity in Glassy Polystyrene. MACROMOL THEOR SIMUL 2021. [DOI: 10.1002/mats.202100021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Roy H. M. Mols
- Polymer Technology Department of Mechanical Engineering Eindhoven University of Technology P. O. Box 513 Eindhoven 5600 MB The Netherlands
- Dutch Polymer Institute PO Box 902 Eindhoven 5600 AX The Netherlands
| | - Georgios G. Vogiatzis
- Dutch Polymer Institute PO Box 902 Eindhoven 5600 AX The Netherlands
- School of Chemical Engineering National Technical University of Athens 9 Heroon Polytechniou Street, Zografou Campus Athens GR‐15780 Greece
| | - Lambèrt C. A. van Breemen
- Polymer Technology Department of Mechanical Engineering Eindhoven University of Technology P. O. Box 513 Eindhoven 5600 MB The Netherlands
| | - Markus Hütter
- Polymer Technology Department of Mechanical Engineering Eindhoven University of Technology P. O. Box 513 Eindhoven 5600 MB The Netherlands
| |
Collapse
|
14
|
Skountzos EN, Tsalikis DG, Stephanou PS, Mavrantzas VG. Individual Contributions of Adsorbed and Free Chains to Microscopic Dynamics of Unentangled poly(ethylene Glycol)/Silica Nanocomposite Melts and the Important Role of End Groups: Theory and Simulation. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02485] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Emmanuel N. Skountzos
- Department of Chemical Engineering, University of Patras & FORTH/ICE-HT, Patras, GR 26504, Greece
| | - Dimitrios G. Tsalikis
- Department of Chemical Engineering, University of Patras & FORTH/ICE-HT, Patras, GR 26504, Greece
| | - Pavlos S. Stephanou
- Department of Chemical Engineering, Cyprus University of Technology, 30 Archbishop Kyprianou Str., 3036 Limassol, Cyprus
| | - Vlasis G. Mavrantzas
- Department of Chemical Engineering, University of Patras & FORTH/ICE-HT, Patras, GR 26504, Greece
- Particle Technology Laboratory, Department of Mechanical and Process Engineering, ETH Zürich, CH-8092 Zürich, Switzerland
| |
Collapse
|
15
|
Foroozani Behbahani A, Harmandaris V. Gradient of Segmental Dynamics in Stereoregular Poly(Methyl Methacrylate) Melts Confined between Pristine or Oxidized Graphene Sheets. Polymers (Basel) 2021; 13:830. [PMID: 33800419 PMCID: PMC7962820 DOI: 10.3390/polym13050830] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 02/27/2021] [Accepted: 03/02/2021] [Indexed: 12/03/2022] Open
Abstract
Segmental dynamics in unentangled isotactic, syndiotactic, and atactic poly(methyl methacrylate) (i-, a-, and s-PMMA) melts confined between pristine graphene, reduced graphene oxide, RGO, or graphene oxide, GO, sheets is studied at various temperatures, well above glass transition temperature, via atomistic molecular dynamics simulations. The model RGO and GO sheets have different degrees of oxidization. The segmental dynamics is studied through the analysis of backbone torsional motions. In the vicinity of the model nanosheets (distances less than ≈2 nm), the dynamics slows down; the effect becomes significantly stronger with increasing the concentration of the surface functional groups, and hence increasing polymer/surface specific interactions. Upon decreasing temperature, the ratios of the interfacial segmental relaxation times to the respective bulk relaxation times increase, revealing the stronger temperature dependence of the interfacial segmental dynamics relative to the bulk dynamics. This heterogeneity in temperature dependence leads to the shortcoming of the time-temperature superposition principle for describing the segmental dynamics of the model confined melts. The alteration of the segmental dynamics at different distances, d, from the surfaces is described by a temperature shift, ΔTseg(d) (roughly speaking, shift of a characteristic temperature). Next, to a given nanosheet, i-PMMA has a larger value of ΔTseg than a-PMMA and s-PMMA. This trend correlates with the better interfacial packing and longer trains of i-PMMA chains. The backbone torsional autocorrelation functions are shown in the frequency domain and are qualitatively compared to the experimental dielectric loss spectra for the segmental α-relaxation in polymer nanocomposites. The εT″(f) (analogous of dielectric loss, ε″(f), for torsional motion) curves of the model confined melts are broader (toward lower frequencies) and have lower amplitudes relative to the corresponding bulk curves; however, the peak frequencies of the εT″(f) curves are only slightly affected.
Collapse
Affiliation(s)
- Alireza Foroozani Behbahani
- Institute of Applied and Computational Mathematics, Foundation for Research and Technology-Hellas, GR-71110 Heraklion, Greece
| | - Vagelis Harmandaris
- Institute of Applied and Computational Mathematics, Foundation for Research and Technology-Hellas, GR-71110 Heraklion, Greece
- Department of Mathematics and Applied Mathematics, University of Crete, GR-70013 Heraklion, Greece
- Computation-Based Science and Technology Research Center, The Cyprus Institute, 2121 Nicosia, Cyprus
| |
Collapse
|
16
|
David A, Tartaglino U, Raos G. Towards realistic simulations of polymer networks: tuning vulcanisation and mechanical properties. Phys Chem Chem Phys 2021; 23:3496-3510. [PMID: 33511970 DOI: 10.1039/d0cp05124a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Simulations of coarse-grained network models have long been used to test theoretical predictions about rubber elasticity, while atomistic models are still largely unexplored. Here we devise a novel algorithm for the vulcanisation of united-atom poly(cis-1,4-butadiene), characterize the topology of the resulting networks and test their mechanical properties. We observe clear changes in the network structure when using slower vulcanisation, contrary to the traditional view that cross-linking simply freezes the melt configuration. Non-ideality of our networks reverberates on the distribution of strand length and on the strands deformation, which is highly non-affine, especially for short strands. Nevertheless, we do recover some of the trends observed on ideal bead-and-spring networks and controlled laboratory experiments, such as the linear relationships linking the degree of cross-linking and the density. We also compare different deformation methods and find step-equilibrium protocols to be more reliable. Regardless of the adopted method, it is advisable to precede the deformation by a pre-stretching cycle in order to release internal stresses accumulated during the vulcanisation.
Collapse
Affiliation(s)
- Alessio David
- Department of Chemistry, Materials and Chemical Engineering, "G. Natta", Politecnico di Milano, 20131 Milan, Italy
| | | | | |
Collapse
|
17
|
Ricci E, Vergadou N, Vogiatzis GG, De Angelis MG, Theodorou DN. Molecular Simulations and Mechanistic Analysis of the Effect of CO 2 Sorption on Thermodynamics, Structure, and Local Dynamics of Molten Atactic Polystyrene. Macromolecules 2020; 53:3669-3689. [PMID: 33828339 PMCID: PMC8016389 DOI: 10.1021/acs.macromol.0c00323] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 04/21/2020] [Indexed: 11/30/2022]
Abstract
A simulation strategy encompassing different scales was applied to the systematic study of the effects of CO2 uptake on the properties of atactic polystyrene (aPS) melts. The analysis accounted for the influence of temperature between 450 and 550 K, polymer molecular weights (M w) between 2100 and 31000 g/mol, and CO2 pressures up to 20 MPa on the volumetric, swelling, structural, and dynamic properties of the polymer as well as on the CO2 solubility and diffusivity by performing molecular dynamics (MD) simulations of the system in a fully atomistic representation. A hierarchical scheme was used for the generation of the higher M w polymer systems, which consisted of equilibration at a coarse-grained level of representation through efficient connectivity-altering Monte Carlo simulations, and reverse-mapping back to the atomistic representation, obtaining the configurations used for subsequent MD simulations. Sorption isotherms and associated swelling effects were determined by using an iterative procedure that incorporated a series of MD simulations in the NPT ensemble and the Widom test particle insertion method, while CO2 diffusion coefficients were extracted from long MD runs in the NVE ensemble. Solubility and diffusivity compared favorably with experimental results and with predictions of the Sanchez-Lacombe equation of state, which was reparametrized to capture the M w dependence of polymer properties with greater accuracy. Structural features of the polymer matrix were correctly reproduced by the simulations, and the effects of gas concentration and M w on structure and local dynamics were thoroughly investigated. In the presence of CO2, a significant acceleration of the segmental dynamics of the polymer occurred, more pronouncedly at low M w. The speed-up effect caused by the swelling agent was not limited to the chain ends but affected the whole chain in a similar fashion.
Collapse
Affiliation(s)
- Eleonora Ricci
- Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Bologna, Italy
| | - Niki Vergadou
- Institute of Nanoscience and Nanotechnology, National Center for Scientific Research "Demokritos", Athens, Greece
| | - Georgios G Vogiatzis
- Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Maria Grazia De Angelis
- Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Bologna, Italy
| | - Doros N Theodorou
- School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| |
Collapse
|
18
|
Swain A, Begam N, Chandran S, Bobji MS, Basu JK. Engineering interfacial entropic effects to generate giant viscosity changes in nanoparticle embedded polymer thin films. SOFT MATTER 2020; 16:4065-4073. [PMID: 32286599 DOI: 10.1039/d0sm00019a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Thin polymer and polymer nanocomposite (PNC) films are being extensively used as advanced functional coating materials in various technological applications. Since it is widely known that various properties of these thin films, especially their thermo-mechanical behavior, can be considerably different from the bulk depending on the thickness as well as interaction with surrounding media, it is imperative to study these properties directly on the films. However, quite often, it becomes difficult to perform these measurements reliably due to a dearth of techniques, especially to measure mechnical or transport properties like the viscosity of thin polymer or PNC films. Here, we demonstrate a new method to study the viscosity of PNC thin films using atomic force microscopy based force-distance spectroscopy. Using this method we investigated viscosity and the glass transition, Tg, of PNC thin films consisting of polymer grafted nanoparticles (PGNPs) embedded in un-entangled homopolymer melt films. The PGNP-polymer interfacial entropic interaction parameter, f, operationally controlled through the ratio of grafted and matrix molecular weight, was systematically tuned while maintaining good dispersion even at very high PGNP loadings, φ. We observed both a significant reduction (low f) and giant enhancement (high f) in the viscosity of the PNC thin films with the effect becoming more prominent with increasing φ. Significantly, none of the established theoretical models for viscosity changes observed earlier in suspensions or polymer nanocomposites can explain the observed viscosity variation. Our results thus not only demonstrate the tunability of the interfacial entropic effect to facilitate a dramatic change in the viscosity of PNC coatings, which could be of great utility in various applications of these materials, but also suggest a new regime of viscosity variation in athermal PNC films indicating the possible need for a new theoretical model.
Collapse
Affiliation(s)
- Aparna Swain
- Department of Physics, Indian Institute of Science, Bangalore 560012, India.
| | - Nafisa Begam
- Department of Physics, Indian Institute of Science, Bangalore 560012, India.
| | | | - M S Bobji
- Indian Institute of Science, Department of Mechanical Engineering, Indian Institute of Science, Bangalore, 560012, India
| | - J K Basu
- Department of Physics, Indian Institute of Science, Bangalore 560012, India.
| |
Collapse
|
19
|
Nieto Simavilla D, Sgouros AP, Vogiatzis GG, Tzoumanekas C, Georgilas V, Verbeeten WMH, Theodorou DN. Molecular Dynamics Test of the Stress-Thermal Rule in Polyethylene and Polystyrene Entangled Melts. Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b02088] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- David Nieto Simavilla
- Universidad de Burgos, Burgos 09006, Spain
- Basque Center for Applied Mathematics, Bilbao 48009, Spain
| | | | | | | | | | | | | |
Collapse
|
20
|
Sgouros AP, Theodorou DN. Atomistic simulations of long-chain polyethylene melts flowing past gold surfaces: structure and wall-slip. Mol Phys 2020. [DOI: 10.1080/00268976.2019.1706775] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- A. P. Sgouros
- School of Chemical Engineering, National Technical University of Athens (NTUA), Athens, Greece
| | - D. N. Theodorou
- School of Chemical Engineering, National Technical University of Athens (NTUA), Athens, Greece
| |
Collapse
|
21
|
Sgouros AP, Vogiatzis GG, Megariotis G, Tzoumanekas C, Theodorou DN. Multiscale Simulations of Graphite-Capped Polyethylene Melts: Brownian Dynamics/Kinetic Monte Carlo Compared to Atomistic Calculations and Experiment. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01379] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- A. P. Sgouros
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - G. G. Vogiatzis
- Department of Mechanical Engineering, Eindhoven University of Technology (TU/e), P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - G. Megariotis
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - C. Tzoumanekas
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - D. N. Theodorou
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| |
Collapse
|
22
|
Vogiatzis GG, van Breemen LCA, Hütter M. Network Topology of the States Probed by a Glassy Polymer during Physical Aging. MACROMOL THEOR SIMUL 2019. [DOI: 10.1002/mats.201900036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Georgios Grigorios Vogiatzis
- Polymer TechnologyDepartment of Mechanical EngineeringEindhoven University of Technology PO Box 513 5600 MB Eindhoven The Netherlands
- Dutch Polymer Institute PO Box 902 5600 AX Eindhoven The Netherlands
| | - Lambèrt Cécile Angelo van Breemen
- Polymer TechnologyDepartment of Mechanical EngineeringEindhoven University of Technology PO Box 513 5600 MB Eindhoven The Netherlands
| | - Markus Hütter
- Polymer TechnologyDepartment of Mechanical EngineeringEindhoven University of Technology PO Box 513 5600 MB Eindhoven The Netherlands
| |
Collapse
|
23
|
Lemarchand CA, Bousquet D, Schnell B, Pineau N. A parallel algorithm to produce long polymer chains in molecular dynamics. J Chem Phys 2019; 150:224902. [DOI: 10.1063/1.5065785] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | | | - B. Schnell
- MICHELIN, 23 Place des Carmes Déchaux, 63040 Clermont-Ferrand, France
| | - N. Pineau
- CEA-DAM-DIF, F-91297 Arpajon, France
| |
Collapse
|
24
|
Mavrantzas VG, Pratsinis SE. The impact of molecular simulations in gas-phase manufacture of nanomaterials. Curr Opin Chem Eng 2019. [DOI: 10.1016/j.coche.2019.04.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
25
|
Chatzieleftheriou S, Anogiannakis S, Theodorou DN, Lagaros ND. SimNano: A Trust Region Strategy for Large-Scale Molecular Systems Energy Minimization Based on Exact Second-Order Derivative Information. J Chem Inf Model 2019; 59:190-205. [PMID: 30433778 DOI: 10.1021/acs.jcim.8b00604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this work, a new energy minimization strategy is presented that achieves better convergence properties than the standard algorithms employed in the field (fewer steps and usually a lower minimum) and is also computationally efficient; therefore, it becomes suitable for dealing with large-scale molecular systems. The proposed strategy is integrated into the SimNano energy minimization platform that is also described herein. SimNano relies on the analytical calculation of the molecular systems' gradient vectors and Hessian matrices using the computational modeling framework proposed by the authors ( Chatzieleftheriou , S. ; Adendorff , M. R. ; Lagaros , N. D. Generalized Potential Energy Finite Elements for Modeling Molecular Nanostructures . J. Chem. Inf. Model. 2016 , 56 ( 10 ), 1963 - 1978 ). The basis of the proposed minimization strategy is a trust region algorithm based on exact second-order derivative information. Taking advantage of the Hessian matrices' sparsity, a specialized treatment of the data structure is implemented. The latter is beneficial and often rather necessary, especially in the case of large-scale molecular systems, improving the speed and reducing the memory requirements. In order to demonstrate the efficiency of the proposed energy minimization strategy, several test examples are examined, and the results achieved are compared with those obtained by one of the most popular molecular simulation software packages, i.e., the Large-Scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). The results indicate that the proposed minimization strategy exhibits superior convergence properties compared with the typical algorithms (i.e., nonlinear conjugate gradient algorithm, limited-memory Broyden-Fletcher-Goldfarb-Shanno (LBFGS) algorithm, etc.). The SimNano energy minimization platform can be downloaded from the site http://users.ntua.gr/nlagaros/simnano.html , enabling researchers in the field to build molecular systems and perform energy minimization runs using input files in LAMMPS format.
Collapse
Affiliation(s)
- Stavros Chatzieleftheriou
- Institute of Structural Analysis and Antiseismic Research, Department of Structural Engineering, School of Civil Engineering , National Technical University of Athens , 9 Heroon Polytechniou Str., Zografou Campus , GR-15780 Athens , Greece
| | - Stefanos Anogiannakis
- Department of Materials Science and Engineering, School of Chemical Engineering , National Technical University of Athens , 9 Heroon Polytechniou Str., Zografou Campus , GR-15780 Athens , Greece
| | - Doros N Theodorou
- Department of Materials Science and Engineering, School of Chemical Engineering , National Technical University of Athens , 9 Heroon Polytechniou Str., Zografou Campus , GR-15780 Athens , Greece
| | - Nikos D Lagaros
- Institute of Structural Analysis and Antiseismic Research, Department of Structural Engineering, School of Civil Engineering , National Technical University of Athens , 9 Heroon Polytechniou Str., Zografou Campus , GR-15780 Athens , Greece
| |
Collapse
|
26
|
Kallivokas SV, Sgouros AP, Theodorou DN. Molecular dynamics simulations of EPON-862/DETDA epoxy networks: structure, topology, elastic constants, and local dynamics. SOFT MATTER 2019; 15:721-733. [PMID: 30629083 DOI: 10.1039/c8sm02071j] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Structural, topological, mechanical and dynamical properties of EPON-862/DETDA epoxy networks are investigated with Molecular Dynamics (MD) simulations. The epoxy networks are composed of the resin Diglycidyl Ether Bisphenol F (DGEBF), also known as EPON-862, and the hardener Diethyl Toluene Diamine (DETDA). Systems with four different crosslinking degrees are examined; the effect of the degree of crosslinking on studied properties is thus determined. The computed quantities are retrieved by employing several simulation strategies and numerical methods of statistical mechanics in order to gain a rigorous and solid understanding of the aforementioned properties as well as to assess the accuracy and applicability of the methods employed. We quantify and analyze the local structure of the EPON-862/DETDA epoxy networks through the partial pair distribution functions, the Faber-Ziman partial structure factors and through simulated X-ray diffraction patterns, demonstrating good agreement with an experimental spectrum from a similar epoxy resin. The topology of the networks is examined with the aim of assessing percolation of connectivity, the properties of network fragments (subnetworks), and the distribution of functionalities of the crosslinks. The elastic constants of the systems are retrieved by employing two equilibrium (analysis of volume fluctuations, Parrinello-Rahman strain fluctuation relation) and one nonequilibrium (uniaxial tension/compression deformations at prescribed rate) method. Finally, the glass temperatures of the systems are estimated by calculating the density as a function of temperature and by analyzing the reorientational dynamics of bond vectors which describe relaxation processes at the segment level.
Collapse
Affiliation(s)
- Spyros V Kallivokas
- School of Chemical Engineering, Department of Materials Science and Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece.
| | - Aristotelis P Sgouros
- School of Chemical Engineering, Department of Materials Science and Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece.
| | - Doros N Theodorou
- School of Chemical Engineering, Department of Materials Science and Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece.
| |
Collapse
|
27
|
|
28
|
Koutsoumpis S, Klonos P, Raftopoulos KN, Papadakis CM, Bikiaris D, Pissis P. Morphology, thermal properties and molecular dynamics of syndiotactic polystyrene (s-PS) nanocomposites with aligned graphene oxide and graphene nanosheets. POLYMER 2018. [DOI: 10.1016/j.polymer.2018.08.052] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
29
|
Skountzos EN, Mermigkis PG, Mavrantzas VG. Molecular Dynamics Study of an Atactic Poly(methyl methacrylate)–Carbon Nanotube Nanocomposite. J Phys Chem B 2018; 122:9007-9021. [DOI: 10.1021/acs.jpcb.8b06631] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Emmanuel N. Skountzos
- Department of Chemical Engineering, University of Patras & FORTH/ICE-HT, Patras GR 26504, Greece
| | - Panagiotis G. Mermigkis
- Department of Chemical Engineering, University of Patras & FORTH/ICE-HT, Patras GR 26504, Greece
| | - Vlasis G. Mavrantzas
- Department of Chemical Engineering, University of Patras & FORTH/ICE-HT, Patras GR 26504, Greece
- Particle Technology Laboratory, Department of Mechanical and Process Engineering, ETH Zürich, CH-8092 Zürich, Switzerland
| |
Collapse
|
30
|
Ibrahim M, Begam N, Padmanabhan V, Basu JK. Correlation between grafted nanoparticle-matrix polymer interface wettability and slip in polymer nanocomposites. SOFT MATTER 2018; 14:6076-6082. [PMID: 29989129 DOI: 10.1039/c8sm01072b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Controlling and understanding the flow properties of polymer nanocomposites (PNC) is very important in realising their potential for various applications. In this study we report molecular dynamics simulation studies of slip between a rotating polymer-grafted nanoparticle and the surrounding free linear matrix chains. By varying the interface wettability between the nanoparticle and matrix chains defined by the parameter f, the ratio of the graft to the matrix chain length, or the graft chain density, Σ, we were able to tune the interface slip, δ, significantly. Both f and Σ alter the interface wettability by changing the matrix chain penetration depth, λ, into the graft chain layer. We observed a large value of δ at smaller f or Σ which reduces with an increasing value of the respective parameters. Since interface slip is also likely to affect other properies of PNCs, like viscosity and the glass transition, we suggest that these parameters could become useful tools to control the flow and mechanical properties of PNCs made with grafted nanoparticles.
Collapse
Affiliation(s)
- Mohd Ibrahim
- Department of Physics, Indian Institute of Science, Bangalore, 560 012, India.
| | | | | | | |
Collapse
|
31
|
|
32
|
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.
Collapse
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
| |
Collapse
|
33
|
Kumar S, Pattanayek SK. Semi-flexible polymer engendered aggregation/dispersion of fullerene (C60) nano-particles: An atomistic investigation. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2018.04.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
34
|
Ren KX, Jia XM, Jiao GS, Chen T, Qian HJ, Lu ZY. Interfacial Properties and Hopping Diffusion of Small Nanoparticle in Polymer/Nanoparticle Composite with Attractive Interaction on Side Group. Polymers (Basel) 2018; 10:E598. [PMID: 30966632 PMCID: PMC6403981 DOI: 10.3390/polym10060598] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 05/21/2018] [Accepted: 05/25/2018] [Indexed: 12/03/2022] Open
Abstract
The diffusion dynamics of fullerene (C 60 ) in unentangled linear atactic polystyrene (PS) and polypropylene (PP) melts and the structure and dynamic properties of polymers in interface area are investigated by performing all-atom molecular dynamics simulations. The comparison of the results in two systems emphasises the influence of local interactions exerted by polymer side group on the diffusion dynamics of the nanoparticle. In the normal diffusive regime at long time scales, the displacement distribution function (DDF) follows a Gaussian distribution in PP system, indicating a normal diffusion of C 60 . However, we observe multiple peaks in the DDF curve for C 60 diffusing in PS melt, which indicates a diffusion mechanism of hopping of C 60 . The attractive interaction between C 60 and phenyl ring side groups are found to be responsible for the observed hopping diffusion. In addition, we find that the C 60 is dynamically coupled with a subsection of a tetramer on PS chain, which has a similar size with C 60 . The phenyl ring on PS chain backbone tends to have a parallel configuration in the vicinity of C 60 surface, therefore neighbouring phenyl rings can form chelation effect on the C 60 surface. Consequently, the rotational dynamics of phenyl ring and the translational diffusion of styrene monomers are found to be slowed down in this interface area. We hope our results can be helpful for understanding of the influence of the local interactions on the nanoparticle diffusion dynamics and interfacial properties in polymer/nanoparticle composites.
Collapse
Affiliation(s)
- Kai-Xin Ren
- State Key Laboratory of Supramolecular Structure and Materials, and Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China.
| | - Xiang-Meng Jia
- State Key Laboratory of Supramolecular Structure and Materials, and Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China.
| | - Gui-Sheng Jiao
- State Key Laboratory of Supramolecular Structure and Materials, and Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China.
| | - Tao Chen
- State Key Laboratory of Supramolecular Structure and Materials, and Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China.
| | - Hu-Jun Qian
- State Key Laboratory of Supramolecular Structure and Materials, and Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China.
| | - Zhong-Yuan Lu
- State Key Laboratory of Supramolecular Structure and Materials, and Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China.
| |
Collapse
|
35
|
Sulym I, Goncharuk O, Sternik D, Terpilowski K, Derylo-Marczewska A, Borysenko MV, Gun’ko VM. Nanooxide/Polymer Composites with Silica@PDMS and Ceria-Zirconia-Silica@PDMS: Textural, Morphological, and Hydrophilic/Hydrophobic Features. NANOSCALE RESEARCH LETTERS 2017; 12:152. [PMID: 28249372 PMCID: PMC5328891 DOI: 10.1186/s11671-017-1935-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 02/20/2017] [Indexed: 06/06/2023]
Abstract
SiO2@PDMS and CeO2-ZrO2-SiO2@PDMS nanocomposites were prepared and studied using nitrogen adsorption-desorption, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), measurements of advancing and receding contact angles with water, and microcalorimetry. The pore size distributions indicate that the textural characteristics change after oxide modification by poly(dimethylsiloxane) (PDMS). Composites are characterized by mainly mesoporosity and macroporosity of aggregates of oxide nanoparticles or oxide@PDMS nanoparticles and their agglomerates. The FT-IR spectra show that PDMS molecules cover well the oxide surface, since the intensity of the band of free silanols at 3748 cm-1 decreases with increasing PDMS concentration and it is absent in the IR spectrum at C PDMS ≥ 20 wt% that occurs due to the hydrogen bonding of the PDMS molecules to the surface hydroxyls. SEM images reveal that the inter-particle voids are gradually filled and aggregates are re-arranged and increase from 20 to 200 nm in size with the increasing polymer concentration. The highest hydrophobicity (contact angle θ = 140° at C PDMS = 20-40 wt%) is obtained for the CeO2-ZrO2-SiO2@PDMS nanocomposites. The heat of composite immersion in water shows a tendency to decrease with increasing PDMS concentration.
Collapse
Affiliation(s)
- Iryna Sulym
- Chuiko Institute of Surface Chemistry, National Academy of Science of Ukraine, 17 General Naumov Street, 03164 Kiev, Ukraine
| | - Olena Goncharuk
- Chuiko Institute of Surface Chemistry, National Academy of Science of Ukraine, 17 General Naumov Street, 03164 Kiev, Ukraine
| | - Dariusz Sternik
- Department of Physicochemistry of Solid Surface, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031, Lublin, Poland
| | - Konrad Terpilowski
- Department of Interfacial Phenomena, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031, Lublin, Poland
| | - Anna Derylo-Marczewska
- Department of Physicochemistry of Solid Surface, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031, Lublin, Poland
| | - Mykola V. Borysenko
- Chuiko Institute of Surface Chemistry, National Academy of Science of Ukraine, 17 General Naumov Street, 03164 Kiev, Ukraine
| | - Vladimir M. Gun’ko
- Chuiko Institute of Surface Chemistry, National Academy of Science of Ukraine, 17 General Naumov Street, 03164 Kiev, Ukraine
| |
Collapse
|
36
|
Sgouros AP, Vogiatzis GG, Kritikos G, Boziki A, Nikolakopoulou A, Liveris D, Theodorou DN. Molecular Simulations of Free and Graphite Capped Polyethylene Films: Estimation of the Interfacial Free Energies. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b01808] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. P. Sgouros
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - G. G. Vogiatzis
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - G. Kritikos
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - A. Boziki
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - A. Nikolakopoulou
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - D. Liveris
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - D. N. Theodorou
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| |
Collapse
|
37
|
Hinkle KR, Phelan FR. Solvation of Carbon Nanoparticles in Water/Alcohol Mixtures: Using Molecular Simulation To Probe Energetics, Structure, and Dynamics. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2017; 121:22926-22938. [PMID: 29760837 PMCID: PMC5947879 DOI: 10.1021/acs.jpcc.7b07769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Molecular dynamics simulations were used to examine the solvation behavior of buckminsterfullerene and single-walled carbon nanotubes (SWCNT) in a range of water/alcohol solvent compositions at 1 atm and 300 K. Results indicate that the alcohols assume the role of pseudosurfactants by shielding the nanotube from the more unfavorable interactions with polar water molecules. This is evident in both the free energies of transfer (ΔΔGwater→xOH = -68.1 kJ/mol and -86.5 kJ/mol for C60 in methanol and ethanol; ΔΔGwater→xOH = -345.6 kJ/mol and -421.2 kJ/mol for the (6,5)-SWCNT in methanol and ethanol) and the composition of the solvation shell at intermediate alcohol concentrations. Additionally, we have observed the retardation of both the translational and rotational dynamics of molecules near the nanoparticle surface through use of time correlation functions. A 3-fold increase in the residence times of the alcohol molecules within the solvation shells at low concentrations further reveals their surfactant-like behavior. Such interactions are important when considering the complex molecular environment present in many schemes used for nanoparticle purification techniques.
Collapse
|
38
|
Tzounis PN, Anogiannakis SD, Theodorou DN. General Methodology for Estimating the Stiffness of Polymer Chains from Their Chemical Constitution: A Single Unperturbed Chain Monte Carlo Algorithm. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b00645] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Stefanos D. Anogiannakis
- School of Chemical Engineering, National Technical University of Athens, GR 15780 Athens, Greece
| | - Doros N. Theodorou
- School of Chemical Engineering, National Technical University of Athens, GR 15780 Athens, Greece
| |
Collapse
|
39
|
Jia XM, Shi R, Jiao GS, Chen T, Qian HJ, Lu ZY. Temperature Effect on Interfacial Structure and Dynamics Properties in Polymer/Single-Chain Nanoparticle Composite. MACROMOL CHEM PHYS 2017. [DOI: 10.1002/macp.201700029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Xiang-Meng Jia
- State Key Laboratory of Supramolecular Structure and Materials, and Laboratory of Theoretical and Computational Chemistry; Institute of Theoretical Chemistry; Jilin University; Changchun 130023 China
| | - Rui Shi
- State Key Laboratory of Supramolecular Structure and Materials, and Laboratory of Theoretical and Computational Chemistry; Institute of Theoretical Chemistry; Jilin University; Changchun 130023 China
| | - Gui-Sheng Jiao
- State Key Laboratory of Supramolecular Structure and Materials, and Laboratory of Theoretical and Computational Chemistry; Institute of Theoretical Chemistry; Jilin University; Changchun 130023 China
| | - Tao Chen
- State Key Laboratory of Supramolecular Structure and Materials, and Laboratory of Theoretical and Computational Chemistry; Institute of Theoretical Chemistry; Jilin University; Changchun 130023 China
| | - Hu-Jun Qian
- State Key Laboratory of Supramolecular Structure and Materials, and Laboratory of Theoretical and Computational Chemistry; Institute of Theoretical Chemistry; Jilin University; Changchun 130023 China
| | - Zhong-Yuan Lu
- State Key Laboratory of Supramolecular Structure and Materials, and Laboratory of Theoretical and Computational Chemistry; Institute of Theoretical Chemistry; Jilin University; Changchun 130023 China
| |
Collapse
|
40
|
Sgouros AP, Megariotis G, Theodorou DN. Slip-Spring Model for the Linear and Nonlinear Viscoelastic Properties of Molten Polyethylene Derived from Atomistic Simulations. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b00694] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. P. Sgouros
- School of Chemical Engineering, National Technical University of Athens (NTUA),GR-15780 Athens, Greece
| | - G. Megariotis
- School of Chemical Engineering, National Technical University of Athens (NTUA),GR-15780 Athens, Greece
| | - D. N. Theodorou
- School of Chemical Engineering, National Technical University of Athens (NTUA),GR-15780 Athens, Greece
| |
Collapse
|
41
|
Gaspar H, Teixeira P, Santos R, Fernandes L, Hilliou L, Weir MP, Parnell AJ, Abrams KJ, Hill CJ, Bouwman WG, Parnell SR, King SM, Clarke N, Covas JA, Bernardo G. A Journey along the Extruder with Polystyrene:C60 Nanocomposites: Convergence of Feeding Formulations into a Similar Nanomorphology. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02283] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hugo Gaspar
- Institute
for Polymers and Composites/I3N, University of Minho, 4800-058 Guimarães, Portugal
| | - Paulo Teixeira
- Institute
for Polymers and Composites/I3N, University of Minho, 4800-058 Guimarães, Portugal
| | - Raquel Santos
- Institute
for Polymers and Composites/I3N, University of Minho, 4800-058 Guimarães, Portugal
| | - Liliana Fernandes
- Institute
for Polymers and Composites/I3N, University of Minho, 4800-058 Guimarães, Portugal
| | - Loic Hilliou
- Institute
for Polymers and Composites/I3N, University of Minho, 4800-058 Guimarães, Portugal
| | - Michael P. Weir
- Department
of Physics and Astronomy, The University of Sheffield, Sheffield S3 7RH, United Kingdom
| | - Andrew J. Parnell
- Department
of Physics and Astronomy, The University of Sheffield, Sheffield S3 7RH, United Kingdom
| | - Kerry J. Abrams
- Department
of Materials Science and Engineering, The University of Sheffield, Sheffield S1 3JD, United Kingdom
| | - Christopher J. Hill
- Department
of Biomedical Science, The University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Wim G. Bouwman
- Faculty
of Applied Sciences, Delft University of Technology, Mekelweg
15, 2629 JB Delft, Netherlands
| | - Steven R. Parnell
- Faculty
of Applied Sciences, Delft University of Technology, Mekelweg
15, 2629 JB Delft, Netherlands
| | - Stephen M. King
- ISIS Pulsed
Neutron Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - Nigel Clarke
- Department
of Physics and Astronomy, The University of Sheffield, Sheffield S3 7RH, United Kingdom
| | - José A. Covas
- Institute
for Polymers and Composites/I3N, University of Minho, 4800-058 Guimarães, Portugal
| | - Gabriel Bernardo
- Institute
for Polymers and Composites/I3N, University of Minho, 4800-058 Guimarães, Portugal
| |
Collapse
|
42
|
Klonos P, Kyritsis A, Bokobza L, Gun’ko VM, Pissis P. Interfacial effects in PDMS/titania nanocomposites studied by thermal and dielectric techniques. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2016.04.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
43
|
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.
Collapse
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
| |
Collapse
|
44
|
Volgin IV, Larin SV, Abad E, Lyulin SV. Molecular Dynamics Simulations of Fullerene Diffusion in Polymer Melts. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02050] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Igor V. Volgin
- Institute
of Macromolecular Compounds, Russian Academy of Sciences, Bolshoj
pr. V.O., 31, 199004 Saint Petersburg, Russia
| | - Sergey V. Larin
- Institute
of Macromolecular Compounds, Russian Academy of Sciences, Bolshoj
pr. V.O., 31, 199004 Saint Petersburg, Russia
| | - Enrique Abad
- Departamento
de Física Aplicada and Instituto de Computación Científica
Avanzada (ICCAEX), Centro Universitario de Mérida, Universidad de Extremadura, E-06800 Mérida, Spain
| | - Sergey V. Lyulin
- Institute
of Macromolecular Compounds, Russian Academy of Sciences, Bolshoj
pr. V.O., 31, 199004 Saint Petersburg, Russia
- Physical
Faculty, Saint-Petersburg University, Ulyanovskaya str. 1, 198504 Petrodvorets, Russia
| |
Collapse
|
45
|
Mathioudakis IG, Vogiatzis GG, Tzoumanekas C, Theodorou DN. Multiscale simulations of PS-SiO2 nanocomposites: from melt to glassy state. SOFT MATTER 2016; 12:7585-7605. [PMID: 27532769 DOI: 10.1039/c6sm01536k] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The interaction energetics, molecular packing, entanglement network properties, segmental dynamics, and elastic constants of atactic polystyrene-amorphous silica nanocomposites in the molten and the glassy state are studied via molecular simulations using two interconnected levels of representation: (a) a coarse-grained one, wherein each polystyrene repeat unit is mapped onto a single "superatom" and the silica nanoparticle is viewed as a solid sphere. Equilibration at all length scales at this level is achieved via connectivity-altering Monte Carlo simulations. (b) A united-atom (UA) level, wherein the polymer chains are represented in terms of a united-atom forcefield and the silica nanoparticle is represented in terms of a simplified, fully atomistic model. Initial configurations for UA molecular dynamics (MD) simulations are obtained by reverse mapping well-equilibrated coarse-grained configurations. By analysing microcanonical UA MD trajectories, the polymer density profile is studied and the polymer is found to exhibit layering in the vicinity of the nanoparticle surface. An estimate of the enthalpy of mixing between polymer and nanoparticles, derived from the UA simulations, compares favourably against available experimental values. The dynamical behaviour of polystyrene (in neat and filled melt systems) is characterized in terms of bond orientation and dihedral angle time autocorrelation functions. At low concentration in the molten polymer matrix, silica nanoparticles are found to cause a slight deceleration of the segmental dynamics close to their surface compared to the bulk polymer. Well-equilibrated coarse-grained long-chain configurations are reduced to entanglement networks via topological analysis with the CReTA algorithm, yielding a slightly lower density of entanglements in the filled than in the neat systems. UA melt configurations are glassified by MD cooling. The elastic moduli of the resulting glassy nanocomposites are computed through an analysis of strain fluctuations in the undeformed state and through explicit mechanical deformation by MD, showing a stiffening of the polymer in the presence of nanoparticles. UA simulation results for the elastic constants are compared to continuum micromechanical calculations invoked in homogenization models of the overall mechanical behaviour of heterogeneous materials. They can be interpreted in terms of the presence of an "interphase" of approximate thickness 2 nm around the nanoparticles, with elastic constants intermediate between those of the filler and the matrix.
Collapse
Affiliation(s)
- I G Mathioudakis
- School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus, GR-15780 Athens, Greece.
| | | | | | | |
Collapse
|
46
|
Uddin MS, Ju J. Multiscale modeling of a natural rubber: Bridging a coarse-grained molecular model to the rubber network theory. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.08.037] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
47
|
Dielectric spectroscopy investigation on relaxation in polyazomethine/fullerene C 60 nanocomposites. Eur Polym J 2016. [DOI: 10.1016/j.eurpolymj.2016.03.035] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
48
|
Bronnikov S, Kostromin S, Musteaţa V, Cozan V. Dielectric study of side-chain liquid crystalline polyazomethine/fullerene C60 nanocomposite. JOURNAL OF POLYMER RESEARCH 2016. [DOI: 10.1007/s10965-016-0942-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
49
|
Orientation of Anisometric Layered Silicate Particles in Uncompatibilized and Compatibilized Polymer Melts Under Shear Flow: A Dissipative Particle Dynamics Study. MACROMOL THEOR SIMUL 2015. [DOI: 10.1002/mats.201500045] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
50
|
Varanasi SR, Guskova OA, John A, Sommer JU. Water around fullerene shape amphiphiles: A molecular dynamics simulation study of hydrophobic hydration. J Chem Phys 2015; 142:224308. [DOI: 10.1063/1.4922322] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
|