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Chen L, Yi Y, Lan H, Wu J, Yang J, Wu S, Yang W, Lu Z, Peng Q. Dielectric Properties of Benzocyclobutene-Based Resin: A Molecular Dynamics Study. J Phys Chem B 2024; 128:340-349. [PMID: 38152041 DOI: 10.1021/acs.jpcb.3c06782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Benzocyclobutene (BCB)-based resins have garnered considerable attention because of their remarkable dielectric properties and thermal stability. However, in molecular dynamics (MD) simulations, progress in BCB-based resin research has yet to keep pace with experimental advancements, resulting in a shortage of theoretical underpinnings at the molecular level. This study focuses on a novel homopolymer, poly(2-(4-benzocyclobutenyl)-divinylbenzene(DVB-S-BCB)), and devises an interactive methodology suitable for BCB-based resins. We implemented a Python script for the joint relaxation method to construct a three-dimensional model of the cured polymer using MadeA and LAMMPS. We conducted MD simulations to investigate how the cross-linking degree and resin molecular weight influence the dielectric properties of the cured polymer. Furthermore, we analyzed the thermodynamic properties through simulation. The results illustrate that augmenting the cross-linking degree and resin molecular weight results in a higher cross-linking density and reduced free volume, thereby increasing the dielectric constant of the resin. The cross-link density does not increase indefinitely with molecular weight, and after a certain threshold is reached, it cannot have a significant effect on the dielectric constant. The degree of cross-linking exerts a more pronounced impact on the dielectric constant than the molecular weight of the resin. In addition, the simulation results denote the excellent thermodynamic properties of the cured polymer. This study also examines the dielectric and thermodynamic properties of the resin samples that were experimentally prepared. The obtained data successfully confirm the reliability of the simulation results. This study offers novel insights for future simulation research on benzocyclobutene-based resins. Additionally, it provides theoretical support for exploring experimental work on low-dielectric materials in the electronic field.
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Affiliation(s)
- Liang Chen
- School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, Sichuan, China
| | - Yong Yi
- School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, Sichuan, China
| | - Hanming Lan
- School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, Sichuan, China
| | - Ji Wu
- Sichuan University of Science & Engineering, Zigong 643002, China
| | - Junxiao Yang
- School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, Sichuan, China
| | - Song Wu
- School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, Sichuan, China
| | - Wu Yang
- School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, Sichuan, China
| | - Ziyu Lu
- School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, Sichuan, China
| | - Qiuxia Peng
- Sichuan University of Science & Engineering, Zigong 643002, China
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2
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Revelas CJ, Sgouros AP, Lakkas AT, Theodorou DN. Addressing Nanocomposite Systems via 3D-SCFT: Assessment of Smearing Approximation and Irregular Grafting Distributions. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c02474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Affiliation(s)
- Constantinos J. Revelas
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - Aristotelis P. Sgouros
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - Apostolos T. Lakkas
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - Doros N. Theodorou
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
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3
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Sirirak K, Vao-soongnern V. Molecular simulation of structural properties of polymer blend nanofilms. JOURNAL OF POLYMER RESEARCH 2023. [DOI: 10.1007/s10965-022-03431-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Striolo A, Huang S. Upcoming Transformations in Integrated Energy/Chemicals Sectors: Some Challenges and Several Opportunities. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:21527-21541. [PMID: 36605781 PMCID: PMC9806836 DOI: 10.1021/acs.jpcc.2c05192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 11/30/2022] [Indexed: 06/17/2023]
Abstract
The sociopolitical events over the past few years led to transformative changes in both the energy and chemical sectors. One of the most evident consequences of these events is the significant focus on sustainability. In fact, rather than an engaging discussion within elite social circles, the search for sustainability is now one of the hard requirements investors impose on companies. The concept of sustainability itself has developed since its inception, and now it encompasses environmental as well as socioeconomic aspects. The major players in the energy and chemical sectors seem to embrace these changes and the related challenges; in most cases, tangible ambitious goals have been proposed. For example, bp aims "to become a net zero company by 2050 or sooner, and to help the world get to net zero". Although tragic events such as the war in Ukraine directly affect global supply chains, leading to some reconsiderations in medium-term industrial and political strategies, trends and public demands seem determined to pursue ambitious sustainable goals, as tangible as the European Union's "Fit for 55" climate package, approved on May 12, 2022, which effectively bans internal combustion engines for new passenger cars and light commercial vehicles from 2035. These trends will likely lead to profound changes in both the chemical and energy sectors. While some predictions may miss the target, speculating about upcoming challenges and opportunities could help us prepare for the future. This is the purpose of this brief Perspective.
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Affiliation(s)
- Alberto Striolo
- School
of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma 73019, United States
- Department
of Chemical Engineering, University College
London, London, U.K. WC1E 7JE
| | - Shanshan Huang
- Applied
Sciences, Innovation and Engineering, BP
International Ltd., Sunbury-On-Thames, U.K. TW16 7LN
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5
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Local conformations and heterogeneities in structures and dynamics of isotactic polypropylene adsorbed onto carbon fiber. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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6
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Truszkowska A, Boldini A, Porfiri M. Plating of Ion‐Exchange Membranes: A Molecular Dynamics Study. ADVANCED THEORY AND SIMULATIONS 2022. [DOI: 10.1002/adts.202200523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Agnieszka Truszkowska
- Mechanical and Aerospace Engineering Tandon School of Engineering New York University Six MetroTech Center Brooklyn NY 11201 USA
- Center for Urban Science and Progress Tandon School of Engineering New York University 370 Jay Street Brooklyn NY 11201 USA
- Chemical and Materials Engineering The University of Alabama in Huntsville 301 Sparkman Drive Huntsville AL 35899 USA
| | - Alain Boldini
- Mechanical and Aerospace Engineering Tandon School of Engineering New York University Six MetroTech Center Brooklyn NY 11201 USA
- Center for Urban Science and Progress Tandon School of Engineering New York University 370 Jay Street Brooklyn NY 11201 USA
| | - Maurizio Porfiri
- Mechanical and Aerospace Engineering Tandon School of Engineering New York University Six MetroTech Center Brooklyn NY 11201 USA
- Center for Urban Science and Progress Tandon School of Engineering New York University 370 Jay Street Brooklyn NY 11201 USA
- Biomedical Engineering Tandon School of Engineering New York University Six MetroTech Center Brooklyn NY 11201 USA
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7
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Sgouros AP, Revelas CJ, Lakkas AT, Theodorou DN. Solvation Free Energy of Dilute Grafted (Nano)Particles in Polymer Melts via the Self-Consistent Field Theory. J Phys Chem B 2022; 126:7454-7474. [DOI: 10.1021/acs.jpcb.2c05306] [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)
- Aristotelis P. Sgouros
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - Constantinos J. Revelas
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - Apostolos T. Lakkas
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - Doros N. Theodorou
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
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8
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Hong X, Yu H, Xu H, Wang X, Jin X, Wu H, Wang F. Competitive adsorption of asphaltene and n-heptane on quartz surfaces and its effect on crude oil transport through nanopores. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Surface morphology effects on clathrate hydrate wettability. J Colloid Interface Sci 2021; 611:421-431. [PMID: 34968961 DOI: 10.1016/j.jcis.2021.12.083] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/08/2021] [Accepted: 12/13/2021] [Indexed: 11/23/2022]
Abstract
HYPOTHESIS Clathrate hydrates preferentially form at interfaces; hence, wetting properties play an important role in their formation, growth, and agglomeration. Experimental evidence suggests that the hydrate preparation process can strongly affect contact angle measurements, leading to the different results reported in the literature. These differences hamper technological progress. We hypothesize that changes in hydrate surface morphologies are responsible for the wide variation of contact angles reported in the literature. EXPERIMENTS Experimental testing of our hypothesis is problematic due to the preparation history of hydrates on their surface properties, and the difficulties in advanced surface characterization. Thus, we employ molecular dynamics simulations, which allow us to systematically change the interfacial features and the system composition. Implementing advanced algorithms, we quantify fundamental thermodynamic properties to validate our observations. FINDINGS We achieve excellent agreement with experimental observations for both atomically smooth and rough hydrate surfaces. Our results suggest that contact line pinning forces, enhanced by surface heterogeneity, are accountable for altering water contact angles, thus explaining the differences among reported experimental data. Our analysis and molecular level insights help interpret adhesion force measurements and yield a better understanding of the agglomeration between hydrate particles, providing a microscopic tool for advancing flow assurance applications.
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Sgouros AP, Knippenberg S, Guillaume M, Theodorou DN. Multiscale simulations of polyzwitterions in aqueous bulk solutions and brush array configurations. SOFT MATTER 2021; 17:10873-10890. [PMID: 34807216 DOI: 10.1039/d1sm01255j] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Zwitterionic polymers are very promising candidates for antifouling materials that exhibit high chemical stability as compared to polyethylene glycol-based systems. A number of simulation and experimental studies have emerged over recent years for the investigation of sulfobetaine-based zwitterionic polymers. Investigating the structural and thermodynamic properties of such polymers requires access to broad time and length regimes, thus necessitating the development of multiscale simulation strategies. The present article advocates a mesoscopic dissipative particle dynamics (DPD) model capable of addressing a wide range of time and length scales. The mesoscopic force field was developed hand-in-hand with atomistic simulations based on the OPLS force field through a bottom-up parameterization procedure that matches the atomistically calculated strand-length, strand-angle and pair distribution functions. The DPD model is validated against atomistic simulations conducted in this work, and against relevant atomistic simulation studies, theoretical predictions and experimental correlations from the literature. Properties examined include the conformations of SPE polymers in dilute bulk aqueous solution, the density profile and thickness of brush arrays as functions of the grafting density and chain length. In addition, we compute the potential of mean force of an approaching hydrophilic or hydrophobic foulant via umbrella sampling as a function of its position relative to the poly-zwitterion-covered surface. The aforementioned observables lead to important insights regarding the conformational tendencies of grafted polyzwitterions and their antifouling properties.
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Affiliation(s)
- Aristotelis P Sgouros
- School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus, GR-15780 Athens, Greece.
| | - Stefan Knippenberg
- Solid State Battery Applicability Laboratory, Solvay SA, 310 Rue de Ransbeek, B-1120 Brussels, Belgium.
| | - Maxime Guillaume
- Solid State Battery Applicability Laboratory, Solvay SA, 310 Rue de Ransbeek, B-1120 Brussels, Belgium.
| | - Doros N Theodorou
- School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus, GR-15780 Athens, Greece.
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11
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Vao-soongnern V. Molecular simulation of molecular and surface properties of random copolymer nanoparticle. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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12
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Truszkowska A, Porfiri M. Molecular dynamics of ionic polymer-metal composites. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2021; 379:20200408. [PMID: 34455834 DOI: 10.1098/rsta.2020.0408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/10/2021] [Indexed: 06/13/2023]
Abstract
Ionic polymer-metal composites (IPMCs) constitute a promising class of soft, active materials with potentially ubiquitous use in science and engineering. Realizing the full potential of IPMCs calls for a deeper understanding of the mechanisms underpinning their most intriguing characteristics: the ability to deform under an electric field and the generation of a voltage upon mechanical deformation. These behaviours are tightly linked to physical phenomena at the level of atoms, including rearrangements of ions and molecules, along with the formation of sub-nanometre thick double layers on the surface of the metal electrodes. Several continuum theories have been developed to describe these phenomena, but their experimental and theoretical validation remains incomplete. IPMC modelling at the atomistic scale could beget valuable support for these efforts, by affording granular analysis of individual atoms. Here, we present a simplified atomistic model of IPMCs based on classical molecular dynamics. The three-dimensional IPMC membrane is constrained by two smooth walls, a simplified analogue of metal electrodes, impermeable only to counterions. The electric field is applied as an additional force acting on all the atoms. We demonstrate the feasibility of simulating counterions' migration and pile-up upon the application of an electric field, similar to experimental observations. By analysing the spatial configuration of atoms and stress distribution, we identify two mechanisms for stress generation. The presented model offers new insight into the physical underpinnings of actuation and sensing in IPMCs. This article is part of the theme issue 'Progress in mesoscale methods for fluid dynamics simulation'.
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Affiliation(s)
- A Truszkowska
- Department of Mechanical and Aerospace Engineering, New York University, Brooklyn, NY, USA
| | - M Porfiri
- Department of Mechanical and Aerospace Engineering, New York University, Brooklyn, NY, USA
- Department of Biomedical Engineering, New York University, Tandon School of Engineering, Brooklyn, NY, USA
- Center for Urban Science and Progress, New York University, Tandon School of Engineering, Brooklyn, NY, USA
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13
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Monte Carlo simulation of molecular and structural properties of random copolymer thin films. J Mol Model 2021; 27:301. [PMID: 34580771 DOI: 10.1007/s00894-021-04927-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 09/21/2021] [Indexed: 10/20/2022]
Abstract
Molecular and structural properties of random copolymer thin films were studied by Monte Carlo simulation of coarse-grained copolymer model on the high coordination lattice. Random copolymer thin films with 50% comonomer fraction with varied interaction strength between comonomer units were studied. Intramolecular interaction was represented by Flory's rotational isomeric state (RIS) model of polyethylene (PE). The non-bonded interactions were treated by Lennard-Jones potential with different parameter sets for comonomer units. When the interaction strength of comonomer is increased, the density of thin films is higher in the inner region and significantly dropped near the free surface along the normal direction of the film. Higher bulk densities and narrower interfacial thicknesses are observed for random copolymer with stronger bead interaction. End beads were segregated at the free surface region and tend to orient perpendicularly to the surface. Copolymer size and shape were significantly changed as a function of bead interaction. For orientation of the whole chain, the largest molecular axis tends to orient along the film surface, but changed toward random orientation for weaker bead interaction. The intra-chain energies were decreased at the surface region while the non-bonded energies were increased. The stronger the comonomer bead attraction, the more change in energetics across the thin film.
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14
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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.
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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
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15
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RuSseL: A Self-Consistent Field Theory Code for Inhomogeneous Polymer Interphases. COMPUTATION 2021. [DOI: 10.3390/computation9050057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this article, we publish the one-dimensional version of our in-house code, RuSseL, which has been developed to address polymeric interfaces through Self-Consistent Field calculations. RuSseL can be used for a wide variety of systems in planar and spherical geometries, such as free films, cavities, adsorbed polymer films, polymer-grafted surfaces, and nanoparticles in melt and vacuum phases. The code includes a wide variety of functional potentials for the description of solid–polymer interactions, allowing the user to tune the density profiles and the degree of wetting by the polymer melt. Based on the solution of the Edwards diffusion equation, the equilibrium structural properties and thermodynamics of polymer melts in contact with solid or gas surfaces can be described. We have extended the formulation of Schmid to investigate systems comprising polymer chains, which are chemically grafted on the solid surfaces. We present important details concerning the iterative scheme required to equilibrate the self-consistent field and provide a thorough description of the code. This article will serve as a technical reference for our works addressing one-dimensional polymer interphases with Self-Consistent Field theory. It has been prepared as a guide to anyone who wishes to reproduce our calculations. To this end, we discuss the current possibilities of the code, its performance, and some thoughts for future extensions.
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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
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Kritikos G, Karatasos K. Effect of Nanofiller Size on the Mechanical Properties of Poly(acrylic acid)/Graphene Oxide Nanocomposites. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00515] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Georgios Kritikos
- Laboratory of Physical Chemistry, Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - Kostas Karatasos
- Laboratory of Physical Chemistry, Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
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18
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Lakkas AT, Sgouros AP, Revelas CJ, Theodorou DN. Structure and thermodynamics of grafted silica/polystyrene dilute nanocomposites investigated through self-consistent field theory. SOFT MATTER 2021; 17:4077-4097. [PMID: 33729266 DOI: 10.1039/d1sm00078k] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Polymer/matrix nanocomposites (PNCs) are materials with exceptional properties. They offer a plethora of promising applications in key industrial sectors. In most cases, it is preferable to disperse the nanoparticles (NPs) homogeneously across the matrix phase. However, under certain conditions NPs might lump together and lead to a composite material with undesirable properties. A common strategy to stabilize the NPs is to graft on their surface polymer chains of the same chemical constitution as the matrix chains. There are several unresolved issues concerning the optimal molar mass and areal density of grafted chains that would ensure best dispersion, given the nanoparticles and the polymer matrix. We propose a model for the prediction of key structural and thermodynamic properties of PNC and apply it to a single spherical silica (SiO2) nanoparticle or planar surface grafted with polystyrene chains embedded at low concentration in a matrix phase of the same chemical constitution. Our model is based on self-consistent field theory, formulated in terms of the Edwards diffusion equation. The properties of the PNC are explored across a broad parameter space, spanning the mushroom regime (low grafting densities, small NPs and chain lengths), the dense brush regime, and the crowding regime (large grafting densities, NP diameters, and chain lengths). We extract several key quantities regarding the distributions and the configurations of the polymer chains, such as the radial density profiles and their decomposition into contributions of adsorbed and free chains, the chains/area profiles, and the tendency of end segments to segregate at the interfaces. Based on our predictions concerning the brush thickness, we revisit the scaling behaviors proposed in the literature and we compare our findings with experiment, relevant simulations, and analytic models, such as Alexander's model for incompressible brushes.
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Affiliation(s)
- Apostolos T Lakkas
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece.
| | - Aristotelis P Sgouros
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece.
| | - Constantinos J Revelas
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece.
| | - Doros N Theodorou
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece.
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19
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Sgouros AP, Revelas CJ, Lakkas AT, Theodorou DN. Potential of Mean Force between Bare or Grafted Silica/Polystyrene Surfaces from Self-Consistent Field Theory. Polymers (Basel) 2021; 13:1197. [PMID: 33917245 PMCID: PMC8068000 DOI: 10.3390/polym13081197] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/02/2021] [Accepted: 04/02/2021] [Indexed: 12/20/2022] Open
Abstract
We investigate single and opposing silica plates, either bare of grafted, in contact with vacuum or melt phases, using self-consistent field theory. Solid-polymer and solid-solid nonbonded interactions are described by means of a Hamaker potential, in conjunction with a ramp potential. The cohesive nonbonded interactions are described by the Sanchez-Lacombe or the Helfand free energy densities. We first build our thermodynamic reference by examining single surfaces, either bare or grafted, under various wetting conditions in terms of the corresponding contact angles, the macroscopic wetting functions (i.e., the work of cohesion, adhesion, spreading and immersion), the interfacial free energies and brush thickness. Subsequently, we derive the potential of mean force (PMF) of two approaching bare plates with melt between them, each time varying the wetting conditions. We then determine the PMF between two grafted silica plates separated by a molten polystyrene film. Allowing the grafting density and the molecular weight of grafted chains to vary between the two plates, we test how asymmetries existing in a real system could affect steric stabilization induced by the grafted chains. Additionally, we derive the PMF between two grafted surfaces in vacuum and determine how the equilibrium distance between the two grafted plates is influenced by their grafting density and the molecular weight of grafted chains. Finally, we provide design rules for the steric stabilization of opposing grafted surfaces (or fine nanoparticles) by taking account of the grafting density, the chain length of the grafted and matrix chains, and the asymmetry among the opposing surfaces.
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Affiliation(s)
- Aristotelis P. Sgouros
- Correspondence: (A.P.S.); (D.N.T.); Tel.: +30-210-772-3216 (A.P.S.); +30-210-772-3157 (D.N.T.)
| | | | | | - Doros N. Theodorou
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece; (C.J.R.); (A.T.L.)
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Sgouros AP, Androulidakis C, Tsoukleri G, Kalosakas G, Delikoukos N, Signetti S, Pugno NM, Parthenios J, Galiotis C, Papagelis K. Efficient Mechanical Stress Transfer in Multilayer Graphene with a Ladder-like Architecture. ACS APPLIED MATERIALS & INTERFACES 2021; 13:4473-4484. [PMID: 33432814 DOI: 10.1021/acsami.0c18774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We report that few graphene flakes embedded into polymer matrices can be mechanically stretched to relatively large deformation (>1%) in an efficient way by adopting a particular ladder-like morphology consisting of consecutive mono-, bi-, tri-, and four-layer graphene units. In this type of flake architecture, all of the layers adhere to the surrounding polymer inducing similar deformation on the individual graphene layers, preventing interlayer sliding and optimizing the strain transfer efficiency. We have exploited Raman spectroscopy to quantify this effect from a mechanical standpoint. The finite element method and molecular dynamics simulations have been used to interpret the above experimental findings. The results suggest that a step pyramid-like architecture of a flake can be ideal for efficient loading of layered materials embedded into a polymer and that there are two prevailing mechanisms that govern axial stress transfer, namely, interfacial shear transfer and axial transmission through the ends. This concept can be easily applied to other two-dimensional materials and related van der Waals heterostructures fabricated either by mechanical exfoliation or chemical vapor deposition by appropriate patterning. This work opens new perspectives in numerous applications, including high volume fraction composites, flexible electronics, and straintronic devices.
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Affiliation(s)
- Aristotelis P Sgouros
- School of Chemical Engineering, National Technical University of Athens (NTUA), Athens 15780, Greece
| | - Charalampos Androulidakis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology-Hellas (FORTH/ICE-HT), Patras 26504, Greece
| | - Georgia Tsoukleri
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology-Hellas (FORTH/ICE-HT), Patras 26504, Greece
| | - George Kalosakas
- Department of Materials Science, University of Patras, Patras 26504, Greece
| | - Nikos Delikoukos
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology-Hellas (FORTH/ICE-HT), Patras 26504, Greece
| | - Stefano Signetti
- Laboratory of Bio-Inspired, Bionic, Nano, Meta Materials & Mechanics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, via Mesiano 77, I-38123 Trento, Italy
| | - Nicola M Pugno
- Laboratory of Bio-Inspired, Bionic, Nano, Meta Materials & Mechanics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, via Mesiano 77, I-38123 Trento, Italy
- School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
| | - John Parthenios
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology-Hellas (FORTH/ICE-HT), Patras 26504, Greece
| | - Costas Galiotis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology-Hellas (FORTH/ICE-HT), Patras 26504, Greece
- Department of Chemical Engineering, University of Patras, Patras 26504, Greece
| | - Konstantinos Papagelis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology-Hellas (FORTH/ICE-HT), Patras 26504, Greece
- School of Physics, Department of Solid State Physics, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
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21
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Kallivokas SV, Sgouros AP, Theodorou DN. Kinetic concepts and local failure in the interfacial shear strength of epoxy-graphene nanocomposites. Phys Rev E 2020; 102:030501. [PMID: 33075882 DOI: 10.1103/physreve.102.030501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 09/02/2020] [Indexed: 11/06/2022]
Abstract
Interfacial shear strength (IFSS) is a key property in the design of composites and nanocomposites. Many simulation studies quantify the interfacial characteristics of sandwichlike specimens in terms of the IFSS and pullout force; a common feature of these studies is that they employ finite model systems and are therefore subject to strong finite size effects. We propose an alternative approach which is applicable to both aperiodic and periodic computational specimens. The interfaces are subjected to multiple shear deformation simulations over a wide range of temperatures (T) and shear stresses (σ_{zx}). From these simulations we collect the failure times (t_{f}); by analyzing them in the framework of an extended Boltzmann-Arrhenius-Zhurkov kinetic equation we derive the IFSS, the limiting stress for barrierless transitions, the activation energy, the activation volume for failure, the sliding velocities, and a local elastic shear modulus for the interface. We test our methodology on epoxy diglycidyl ether bisphenol F-diethyl toluene diamine interfaces in contact with (i) pristine graphene, (ii) graphene with single-atom vacancies, and (iii) graphene with hydroxyl-ΟΗ groups. Differences in the mechanism of interfacial failure among these three systems are discussed.
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Affiliation(s)
- Spyros V Kallivokas
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - Aristotelis P Sgouros
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - Doros N Theodorou
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
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22
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Walker CC, Genzer J, Santiso EE. Effect of Poly(vinyl butyral) Comonomer Sequence on Adhesion to Amorphous Silica: A Coarse-Grained Molecular Dynamics Study. ACS APPLIED MATERIALS & INTERFACES 2020; 12:47879-47890. [PMID: 32921047 DOI: 10.1021/acsami.0c10747] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Modulating a comonomer sequence, in addition to the overall chemical composition, is the key to unlocking the true potential of many existing commercial copolymers. We employ coarse-grained molecular dynamics (MD) simulations to study the behavior of random-blocky poly(vinyl butyral-co-vinyl alcohol) (PVB) melts in contact with an amorphous silica surface, representing the interface found in laminated safety glass. Our two-pronged coarse-graining approach utilizes both macroscopic thermophysical data and all-atom MD simulation data. Polymer-polymer nonbonded interactions are described by the fused-sphere SAFT-γ Mie equation of state, while bonded interactions are derived using Boltzmann inversion to match the bond and angle distributions from all-atom PVB chains. Spatially dependent polymer-surface interactions are mapped from a hydroxylated all-atom amorphous silica slab model and all-atom monomers to an external potential acting on the coarse-grained sites. We discovered an unexpected complex relationship between the blockiness parameter and the adhesion energy. The adhesion strength between PVB copolymers with intermediate VA content and silica was found to be maximal for random-blocky copolymers with a moderately high degree of blockiness rather than for diblock copolymers. We attribute this to two main factors: (1) changes in morphology, which dramatically alter the number of VA beads interacting with the surface and (2) a non-negligible contribution of vinyl butyral (VB) monomers to adhesion energy because of their preference to adsorb to zones with low hydroxyl density on the silica surface.
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Affiliation(s)
- Christopher C Walker
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Jan Genzer
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Erik E Santiso
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
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23
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Kritikos G, Rissanou AN, Harmandaris V, Karatasos K. Bound Layer Polymer Behavior on Graphene and Graphene Oxide Nanosheets. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c01040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Georgios Kritikos
- Laboratory of Physical Chemistry, Department of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Anastassia N. Rissanou
- Institute of Applied and Computational Mathematics, Foundation for Research and Technology - Hellas, 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
| | - Kostas Karatasos
- Laboratory of Physical Chemistry, Department of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
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24
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Behbahani AF, Rissanou A, Kritikos G, Doxastakis M, Burkhart C, Polińska P, Harmandaris VA. Conformations and Dynamics of Polymer Chains in Cis and Trans Polybutadiene/Silica Nanocomposites through Atomistic Simulations: From the Unentangled to the Entangled Regime. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c01030] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Alireza F. Behbahani
- Institute of Applied and Computational Mathematics, Foundation for Research and Technology—Hellas, Heraklion GR-71110, Greece
| | - Anastassia Rissanou
- Institute of Applied and Computational Mathematics, Foundation for Research and Technology—Hellas, Heraklion GR-71110, Greece
| | - Giorgos Kritikos
- Institute of Applied and Computational Mathematics, Foundation for Research and Technology—Hellas, Heraklion GR-71110, Greece
| | - Manolis Doxastakis
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Craig Burkhart
- The Goodyear Tire and Rubber Company, 142 Goodyear Blvd., Akron, Ohio 44305, United States
| | | | - Vagelis A. 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
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25
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Gurina D, Surov O, Voronova M, Zakharov A. Molecular Dynamics Simulation of Polyacrylamide Adsorption on Cellulose Nanocrystals. NANOMATERIALS 2020; 10:nano10071256. [PMID: 32605224 PMCID: PMC7408107 DOI: 10.3390/nano10071256] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/24/2020] [Accepted: 06/25/2020] [Indexed: 11/20/2022]
Abstract
Classical molecular dynamics simulations of polyacrylamide (PAM) adsorption on cellulose nanocrystals (CNC) in a vacuum and a water environment are carried out to interpret the mechanism of the polymer interactions with CNC. The structural behavior of PAM is studied in terms of the radius of gyration, atom–atom radial distribution functions, and number of hydrogen bonds. The structural and dynamical characteristics of the polymer adsorption are investigated. It is established that in water the polymer macromolecules are mainly adsorbed in the form of a coil onto the CNC facets. It is found out that water and PAM sorption on CNC is a competitive process, and water weakens the interaction between the polymer and CNC.
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Affiliation(s)
- Darya Gurina
- Correspondence: (D.G.); (O.S.); Tel.: +7-493-2351-869 (D.G.); +7-493-2351-545 (O.S.)
| | - Oleg Surov
- Correspondence: (D.G.); (O.S.); Tel.: +7-493-2351-869 (D.G.); +7-493-2351-545 (O.S.)
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26
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Jarray A, Wijshoff H, Luiken JA, den Otter WK. Systematic approach for wettability prediction using molecular dynamics simulations. SOFT MATTER 2020; 16:4299-4310. [PMID: 32313919 DOI: 10.1039/d0sm00197j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We present a fast and efficient approach to predict the wettability and spreading of liquids on polymeric substrates. First, a molecular dynamics parameterization is proposed for the calculation of the solubility parameter for 74 compounds including surfactants typically used in inkjet printing. Then, we introduce a molecular geometrical factor to relate the solubility parameter to the surface tension, obtaining estimates in remarkable agreement with experiments. By using a modified Young-Fowkes equation, the contact angles of liquids on various polymeric substrates are determined and their dependence on the hydrogen bonding, dispersion and polar contribution of the solubility parameter are investigated. We find that wetting properties are obtained with a good accuracy when taking into account the hydrogen-bonding and polar interactions in the geometric sum of the solubility parameter. Based on these findings, a 3D wetting space is proposed to evaluate liquids wettability and judge their suitability for specific substrates. This will enable easy formulation of liquids with wettability tailored for a particular surface and application.
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Affiliation(s)
- Ahmed Jarray
- Multi Scale Mechanics (MSM), University of Twente, 7500 AE Enschede, The Netherlands.
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27
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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
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28
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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
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29
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Rivera JL, Douglas JF. Reducing uncertainty in simulation estimates of the surface tension through a two-scale finite-size analysis: thicker is better. RSC Adv 2019; 9:35803-35812. [PMID: 35528077 PMCID: PMC9074429 DOI: 10.1039/c9ra07058c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 10/29/2019] [Indexed: 12/21/2022] Open
Abstract
Recent simulation studies of the surface tension γ, and other properties of thin free-standing films, have revealed unexpected finite size effects in which the variance of the properties vary monotonically with the in-plane width of the films, complicating the extrapolation of estimates of film properties to the thermodynamic limit. We carried out molecular dynamics simulations to determine the origin of this phenomenon, and to address the practical problem of developing a more reliable methodology for estimating γ in the thermodynamic limit. We find that there are two distinct finite size effects that must be addressed in a finite size analysis of γ in thin films. The first finite size scale is the in-plane width of the films and the second scale is the simulation cell size in the transverse direction. Increasing the first scale enhances fluctuations in γ, measured by the standard deviation of their distribution, while increasing the second reduces γ fluctuations due to a corresponding increased ‘freedom’ of the film to fluctuate out of plane. We find that using progressively large simulation cells in the transverse direction, while keeping the film width fixed to an extent in which the full bulk liquid zone is developed, allows us to obtain a smooth extrapolation to the thermodynamic limit, enabling a reduction of the γ uncertainty to a magnitude on the order of 1% for systems having a reasonably large size, i.e., O (1 μm). The variance in the surface tension of systems under vapor/liquid equilibrium is strongly affected by the size of the interfacial area. Wider layers increase the variance, but these increments disappear as the interfacial area grows.![]()
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Affiliation(s)
- José L Rivera
- Laboratorio de Modelamiento y Simulación Molecular, Universidad Michoacana de San Nicolás de Hidalgo Morelia Michoacán 58000 Mexico
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology Gaithersburg Maryland 20899 USA
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30
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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
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31
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Lakkas AT, Sgouros AP, Theodorou DN. Self-Consistent Field Theory Coupled with Square Gradient Theory of Free Surfaces of Molten Polymers and Compared to Atomistic Simulations and Experiment. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00795] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- A. T. Lakkas
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - A. P. Sgouros
- 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
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32
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Rivera JL, Douglas JF. Influence of film thickness on the stability of free-standing Lennard-Jones fluid films. J Chem Phys 2019; 150:144705. [DOI: 10.1063/1.5086284] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- José L. Rivera
- Laboratorio de Modelamiento y Simulación Molecular, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán 58000, Mexico
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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33
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Karatrantos A, Composto RJ, Winey KI, Clarke N. Nanorod Diffusion in Polymer Nanocomposites by Molecular Dynamics Simulations. Macromolecules 2019. [DOI: 10.1021/acs.macromol.8b02141] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Argyrios Karatrantos
- Materials Research and Technology, Luxembourg Institute of Science and Technology, 5, Avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg
| | - Russell J. Composto
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Karen I. Winey
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Nigel Clarke
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom
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34
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Miura T, Funada M, Shimoi Y, Morita H. Simulation Study of the Effects of Nanoporous Structures on Mechanical Properties at Polymer-Metal Interfaces. J Phys Chem B 2019; 123:1161-1170. [PMID: 30677295 DOI: 10.1021/acs.jpcb.8b10556] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We investigated the effect of nanopores on the adhesion behavior at polymer-metal interfaces by molecular dynamics simulation. The effects of shear and extension behavior were examined. In the shear mode, samples with porous substrates showed larger shear forces than those with flat substrates. Meanwhile, the breaking strengths in the extension mode were almost the same for systems with flat and porous substrates. The similar behavior in the extension mode was ascribed to the formation of voids in the polymer layer, which was related to the increase of total system volume and not affected by the presence of pores. We also investigated the relationship between the mechanical properties of polymer-metal interfaces in the shear mode and pore size in detail. Even a very shallow pore with a depth of 0.5 nm produced a large shear force comparable to that of a pore with a depth of 2.0 nm. The shear force increased gradually as the pore diameter became wider. These simulation results revealed that the adhesion forces between polymers and rough metal surfaces are not simply related to the interface area but depend on the pulling mode, pore size, and polymer chain length in a complicated manner.
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Affiliation(s)
- Toshiaki Miura
- National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Umezono , Tsukuba , Ibaraki 305-8568 , Japan
| | - Maki Funada
- Innovative Structural Materials Association (ISMA) , AIST Central 5, 1-1-1 Higashi , Tsukuba , Ibaraki 305-8565 , Japan
| | - Yukihiro Shimoi
- National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Umezono , Tsukuba , Ibaraki 305-8568 , Japan
| | - Hiroshi Morita
- National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Umezono , Tsukuba , Ibaraki 305-8568 , Japan
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35
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Sgouros AP, Lakkas AT, Megariotis G, Theodorou DN. Mesoscopic Simulations of Free Surfaces of Molten Polyethylene: Brownian Dynamics/Kinetic Monte Carlo Coupled with Square Gradient Theory and Compared to Atomistic Calculations and Experiment. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01873] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- A. P. Sgouros
- School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - A. T. Lakkas
- 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
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36
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Behbahani AF, Vaez Allaei SM, Motlagh GH, Eslami H, Harmandaris VA. Structure, Dynamics, and Apparent Glass Transition of Stereoregular Poly(methyl methacrylate)/Graphene Interfaces through Atomistic Simulations. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01160] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Alireza F. Behbahani
- Advanced Polymer Materials and Processing Lab, School of Chemical Engineering, College of Engineering, University of Tehran, Tehran 11155-4563, Iran
- Institute of Applied and Computational Mathematics, Foundation for Research and Technology - Hellas, Heraklion GR-71110, Greece
| | - S. Mehdi Vaez Allaei
- Department of Physics, University of Tehran, Tehran 14395-547, Iran
- School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran
| | - Ghodratollah H. Motlagh
- Advanced Polymer Materials and Processing Lab, School of Chemical Engineering, College of Engineering, University of Tehran, Tehran 11155-4563, Iran
| | - Hossein Eslami
- Department of Chemistry, College of Sciences, Persian Gulf University, Boushehr 75168, Iran
| | - Vagelis A. 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
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37
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Rivera JL, Molina-Rodríguez L, Ramos-Estrada M, Navarro-Santos P, Lima E. Interfacial properties of the ionic liquid [bmim][triflate] over a wide range of temperatures. RSC Adv 2018; 8:10115-10123. [PMID: 35540813 PMCID: PMC9078723 DOI: 10.1039/c8ra00915e] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 02/26/2018] [Indexed: 12/25/2022] Open
Abstract
We carried out molecular dynamics simulations of the liquid/vacuum equilibrium of the ionic liquid [bmim][triflate] in a wide range of temperatures (323.15 to 573.15 K). The results showed liquid phases with high densities even at temperatures close to the decomposition temperature of the liquid. The density and surface tension behaviors are linear across this wide range of temperatures, which is an extension of the behaviors of these systems at low temperatures, where these properties have been experimentally measured. The interfacial region shows peaks of adsorption of the ions; they are ordered, with the alkyl chains of the [bmim] cations pointing out of the liquid, and the tailing angle of the chains becomes 90° at higher temperatures. The alkyl chains are part of the outermost interfacial region, where intra- and intermolecular tangential forces are in equilibrium; thus, they do not contribute to the total surface tension. Unlike simpler organic liquids, the surface tension is composed of positive normal contributions of intermolecular interactions; these are almost in equilibrium with the negative normal contributions of intramolecular interactions, which are mainly vibrations of the distance and the angle of valence. The pressure profiles show that the molecules are in 'crushed' conformations internally in the bulk liquid and even more so in the normal direction at the interface. The total pressure profiles show values with physical meaning, where the tangential peaks show higher values than normal pressures and give rise to the surface tension. Short cutoff radii for the calculation of intermolecular forces (less than 16.5 Å) produce a system that is not mechanically stable in the region of the bulk liquid (confirmed by radial distribution function calculations); this produces a difference between the normal pressure and the average of the tangential pressures, which affects the calculation of the surface tension due to overestimation by up to 20% when using the global expression, which is extensively used for the calculation of surface tension. The use of a sufficiently long cutoff radius avoids these mechanical balance problems.
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Affiliation(s)
- José L Rivera
- Graduate School of Physics Engineering, Universidad Michoacana de San Nicolás de Hidalgo Morelia C.P. 58000 Michoacán Mexico
- Faculty of Chemical Engineering, Universidad Michoacana de San Nicolás de Hidalgo Morelia C.P. 58000 Michoacán Mexico
| | - Luis Molina-Rodríguez
- Faculty of Chemical Engineering, Universidad Michoacana de San Nicolás de Hidalgo Morelia C.P. 58000 Michoacán Mexico
| | - Mariana Ramos-Estrada
- Faculty of Chemical Engineering, Universidad Michoacana de San Nicolás de Hidalgo Morelia C.P. 58000 Michoacán Mexico
| | - Pedro Navarro-Santos
- Institute of Chemical Biology Sciences, Universidad Michoacana de San Nicolás de Hidalgo Morelia C.P. 58000 Michoacán Mexico
| | - Enrique Lima
- Laboratorio de Fisicoquímica y Reactividad de Superficies (LaFReS), Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México Circuito Exterior S/N, CU, Del. Coyoacán Ciudad de México Mexico
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