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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.
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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
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2
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Shamsieva A, Piyanzina I, Minisini B. Amorphous cis-1,4-polybutadiene P-V-T properties from atomistic simulations. J Mol Model 2023; 29:249. [PMID: 37452231 DOI: 10.1007/s00894-023-05658-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 07/08/2023] [Indexed: 07/18/2023]
Abstract
CONTEXT As a result of the diversity of microstructures encountered in cis-1,4-polybutadiene and the variety of measurement methods used, experimental values of variation of glass transition temperature (Tg) with pressure are relatively dispersed. However, atomistic simulations enable access to valuable information for very well-controlled chemistry and structures with a well-defined and systematic acquisition protocol. By varying the temperature and pressure, the specific volume of the melt was computed, yielding results that deviated by only 2% from experimental data. A linear relationship between Tg and pressure was observed, with Tg predicted to be 162 K at zero pressure and a rate of change of Tg with respect to pressure (dTg/dP) of 0.24 K/MPa. METHOD The atomistic dilatometry experiments were conducted on a model of amorphous cis-1,4 polybutadiene with an approximate molecular weight of 5400 g/mol using the LAMMPS code and the all-atom forcefield pcff + . The dilatometry process involved cooling and heating at a rate of 9 × 1012 K/min. The specific volume was calculated by averaging over seven independent configurations for each temperature. The Tait equation was employed to fit the specific volume evolution within the temperature range of 10 to 700 K under different pressures of 0, 60, and 100 MPa.
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Affiliation(s)
- Aigul Shamsieva
- Institute of Physics, Kazan Federal University, Kremlyovskaya St. 18, Kazan, 420008, Republic of Tatarstan, Russia
| | - Irina Piyanzina
- Institute of Physics, Kazan Federal University, Kremlyovskaya St. 18, Kazan, 420008, Republic of Tatarstan, Russia
| | - Benoit Minisini
- Materials Design SARL, 42 Avenue Verdier, 92120, Paris, Montrouge, France.
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3
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Phillies GDJ. Simulational Tests of the Rouse Model. Polymers (Basel) 2023; 15:2615. [PMID: 37376261 DOI: 10.3390/polym15122615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 05/24/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
An extensive review of literature simulations of quiescent polymer melts is given, considering results that test aspects of the Rouse model in the melt. We focus on Rouse model predictions for the mean-square amplitudes ⟨(Xp(0))2⟩ and time correlation functions ⟨Xp(0)Xp(t)⟩ of the Rouse mode Xp(t). The simulations conclusively demonstrate that the Rouse model is invalid in polymer melts. In particular, and contrary to the Rouse model, (i) mean-square Rouse mode amplitudes ⟨(Xp(0))2⟩ do not scale as sin-2(pπ/2N), N being the number of beads in the polymer. For small p (say, p≤3) ⟨(Xp(0))2⟩ scales with p as p-2; for larger p, it scales as p-3. (ii) Rouse mode time correlation functions ⟨Xp(t)Xp(0)⟩ do not decay with time as exponentials; they instead decay as stretched exponentials exp(-αtβ). β depends on p, typically with a minimum near N/2 or N/4. (iii) Polymer bead displacements are not described by independent Gaussian random processes. (iv) For p≠q, ⟨Xp(t)Xq(0)⟩ is sometimes non-zero. (v) The response of a polymer coil to a shear flow is a rotation, not the affine deformation predicted by Rouse. We also briefly consider the Kirkwood-Riseman polymer model.
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Yin F, Yang L, Hou W, Yuan Y, Yu H. Study of dielectric properties of meta-aramid fibers by molecular dynamics methods using modified OPLSAA force field. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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5
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Ngai KL, Capaccioli S, Lunkenheimer P, Loidl A. Arriving at the most plausible interpretation of the dielectric spectra of glycerol with help from quasielastic γ-ray scattering time-domain interferometry. Phys Rev E 2022; 105:054609. [PMID: 35706308 DOI: 10.1103/physreve.105.054609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/10/2022] [Indexed: 06/15/2023]
Abstract
Glycerol is one of the glass-forming liquids selected by Robert H. Cole in 1950 to start his study of molecular dynamics by dielectric spectroscopy. Seventy-one years have gone by and remarkably no consensus has been reached on the nature and identity of the relaxation processes observed in the dielectric spectra. The macroscopic dielectric relaxation data allow different interpretations to yield contrasting results, and it is not possible to determine which one is most plausible. Coming to the rescue is the application of the nuclear γ-resonance time-domain interferometry (TDI) to glycerol by Saito et al. [Phys. Rev. E 105, L012605 (2022)10.1103/PhysRevE.105.L012605]. Their microscopic TDI data potentially can decide which interpretation of the dielectric spectra of glycerol is most plausible. The attempt was made by Saito et al., but there is a problem in their analysis of the dielectric data of glycerol and hence their conclusion is untenable. In this paper, we critically compare four major interpretations with the TDI data in an effort to identify the most plausible interpretation of the relaxation processes constituting the dielectric spectra of glycerol.
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Affiliation(s)
- K L Ngai
- CNR-IPCF, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy
| | - S Capaccioli
- CNR-IPCF, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy
- Dipartimento di Fisica, Università di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy
| | - P Lunkenheimer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, D-86135 Augsburg, Germany
| | - A Loidl
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, D-86135 Augsburg, Germany
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6
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Ren NN, Guan PF, Ngai KL. Isochronal superpositioning of the caged dynamics, the α, and the Johari-Goldstein β relaxations in metallic glasses. J Chem Phys 2021; 155:244502. [PMID: 34972387 DOI: 10.1063/5.0072527] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The superposition of the frequency dispersions of the structural α relaxation determined at different combinations of temperature T and pressure P while maintaining its relaxation time τα(T, P) constant (i.e., isochronal superpositioning) has been well established in molecular and polymeric glass-formers. Not known is whether the frequency dispersion or time dependence of the faster processes including the caged molecule dynamics and the Johari-Goldstein (JG) β relaxation possesses the same property. Experimental investigation of this issue is hindered by the lack of an instrument that can cover all three processes. Herein, we report the results from the study of the problem utilizing molecular dynamics simulations of two different glass-forming metallic alloys. The mean square displacement 〈Δr2t〉, the non-Gaussian parameter α2t, and the self-intermediate scattering function Fsq,t at various combinations of T and P were obtained over broad time range covering the three processes. Isochronal superpositioning of 〈Δr2t〉, α2t, and Fsq,t was observed over the entire time range, verifying that the property holds not only for the α relaxation but also for the caged dynamics and the JG β relaxation. Moreover, we successfully performed density ρ scaling of the time τα2,maxT,P at the peak of α2t and the diffusion coefficient D(T, P) to show both are functions of ργ/T with the same γ. It follows that the JG β relaxation time τβ(T, P) is also a function of ργ/T since τα2,maxT,P corresponds to τβ(T, P).
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Affiliation(s)
- N N Ren
- Beijing Computational Science Research Center, Beijing 100193, China
| | - P F Guan
- Beijing Computational Science Research Center, Beijing 100193, China
| | - K L Ngai
- CNR-IPCF, Largo B. Pontecorvo 3, I-56127 Pisa, Italy
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7
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Cao Y, Cao W, Yang X, Liu C, Qi X. Theoretical investigation of polymer molecular structure influence on dielectric properties and mechanical properties. POLYM ADVAN TECHNOL 2021. [DOI: 10.1002/pat.5499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Yuying Cao
- Institute for Frontier Materials Deakin University Geelong Victoria Australia
| | - Weihua Cao
- School of Mechanical Engineering Yanshan University Qinhuangdao China
| | - Xiao Yang
- School of Mechanical Engineering Yanshan University Qinhuangdao China
| | - Changxin Liu
- Key Laboratory of Self‐Lubricating Spherical Plain Bearing Technology of Hebei Province Yanshan University Qinhuangdao China
| | - Xiaowen Qi
- Key Laboratory of Self‐Lubricating Spherical Plain Bearing Technology of Hebei Province Yanshan University Qinhuangdao China
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8
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Liu TQ, Zheng F, Ma X, Ding TM, Chen S, Jiang W, Zhang SY, Lu Q. High heat-resistant polyimide films containing quinoxaline moiety for flexible substrate applications. POLYMER 2020. [DOI: 10.1016/j.polymer.2020.122963] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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9
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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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10
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Adrjanowicz K, Winkler R, Chat K, Duarte DM, Tu W, Unni AB, Paluch M, Ngai KL. Study of Increasing Pressure and Nanopore Confinement Effect on the Segmental, Chain, and Secondary Dynamics of Poly(methylphenylsiloxane). Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00473] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- K. Adrjanowicz
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - R. Winkler
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - K. Chat
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - D. M. Duarte
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - W. Tu
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - A. B. Unni
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - M. Paluch
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - K. L. Ngai
- CNR-IPCF, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy
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11
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Kołodziej S, Pawlus S, Ngai KL, Paluch M. Verifying the Approximate Coinvariance of the α and Johari–Goldstein β Relaxation Times to Variations of Pressure and Temperature in Polyisoprene. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00811] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sławomir Kołodziej
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
| | - Sebastian Pawlus
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center
for Education and Interdisciplinary Research, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
| | - K. L. Ngai
- CNR-IPCF, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy
| | - Marian Paluch
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian Center
for Education and Interdisciplinary Research, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
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12
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Ngai KL, Paluch M, Rodríguez-Tinoco C. Why is the change of the Johari–Goldstein β-relaxation time by densification in ultrastable glass minor? Phys Chem Chem Phys 2018; 20:27342-27349. [DOI: 10.1039/c8cp05107k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Coupling-Model-based theoretical explanation of the minor change of JG β-relaxation achieved by ultrastability in contrast to the dramatic change in α-relaxation.
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Affiliation(s)
| | - Marian Paluch
- Silesian Center for Education and Interdisciplinary Research
- 41-500 Chorzow
- Poland
- Institute of Physics
- University of Silesia
| | - Cristian Rodríguez-Tinoco
- Silesian Center for Education and Interdisciplinary Research
- 41-500 Chorzow
- Poland
- Institute of Physics
- University of Silesia
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13
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Puosi F, Chulkin O, Bernini S, Capaccioli S, Leporini D. Thermodynamic scaling of vibrational dynamics and relaxation. J Chem Phys 2016; 145:234904. [DOI: 10.1063/1.4971297] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- F. Puosi
- Dipartimento di Fisica “Enrico Fermi,” Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa, Italy
| | - O. Chulkin
- Dipartimento di Fisica “Enrico Fermi,” Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa, Italy
| | - S. Bernini
- Dipartimento di Fisica “Enrico Fermi,” Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa, Italy
| | - S. Capaccioli
- Dipartimento di Fisica “Enrico Fermi,” Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa, Italy
- IPCF-CNR, UOS, Pisa, Italy
| | - D. Leporini
- Dipartimento di Fisica “Enrico Fermi,” Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa, Italy
- IPCF-CNR, UOS, Pisa, Italy
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14
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Veldhorst AA, Dyre JC, Schrøder TB. Scaling of the dynamics of flexible Lennard-Jones chains: Effects of harmonic bonds. J Chem Phys 2016; 143:194503. [PMID: 26590538 DOI: 10.1063/1.4934973] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The previous paper [A. A. Veldhorst et al., J. Chem. Phys. 141, 054904 (2014)] demonstrated that the isomorph theory explains the scaling properties of a liquid of flexible chains consisting of ten Lennard-Jones particles connected by rigid bonds. We here investigate the same model with harmonic bonds. The introduction of harmonic bonds almost completely destroys the correlations in the equilibrium fluctuations of the potential energy and the virial. According to the isomorph theory, if these correlations are strong a system has isomorphs, curves in the phase diagram along which structure, dynamics, and the excess entropy are invariant. The Lennard-Jones chain liquid with harmonic bonds does have curves in the phase diagram along which the structure and dynamics are invariant. The excess entropy is not invariant on these curves, which we refer to as "pseudoisomorphs." In particular, this means that Rosenfeld's excess-entropy scaling (the dynamics being a function of excess entropy only) does not apply for the Lennard-Jones chain with harmonic bonds.
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Affiliation(s)
- Arno A Veldhorst
- Department of Sciences, DNRF Center "Glass and Time," IMFUFA, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark
| | - Jeppe C Dyre
- Department of Sciences, DNRF Center "Glass and Time," IMFUFA, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark
| | - Thomas B Schrøder
- Department of Sciences, DNRF Center "Glass and Time," IMFUFA, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark
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Veldhorst AA, Dyre JC, Schrøder TB. Scaling of the dynamics of flexible Lennard-Jones chains. J Chem Phys 2015; 141:054904. [PMID: 25106610 DOI: 10.1063/1.4888564] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The isomorph theory provides an explanation for the so-called power law density scaling which has been observed in many molecular and polymeric glass formers, both experimentally and in simulations. Power law density scaling (relaxation times and transport coefficients being functions of ρ(γ(S)), where ρ is density, T is temperature, and γ(S) is a material specific scaling exponent) is an approximation to a more general scaling predicted by the isomorph theory. Furthermore, the isomorph theory provides an explanation for Rosenfeld scaling (relaxation times and transport coefficients being functions of excess entropy) which has been observed in simulations of both molecular and polymeric systems. Doing molecular dynamics simulations of flexible Lennard-Jones chains (LJC) with rigid bonds, we here provide the first detailed test of the isomorph theory applied to flexible chain molecules. We confirm the existence of isomorphs, which are curves in the phase diagram along which the dynamics is invariant in the appropriate reduced units. This holds not only for the relaxation times but also for the full time dependence of the dynamics, including chain specific dynamics such as the end-to-end vector autocorrelation function and the relaxation of the Rouse modes. As predicted by the isomorph theory, jumps between different state points on the same isomorph happen instantaneously without any slow relaxation. Since the LJC is a simple coarse-grained model for alkanes and polymers, our results provide a possible explanation for why power-law density scaling is observed experimentally in alkanes and many polymeric systems. The theory provides an independent method of determining the scaling exponent, which is usually treated as an empirical scaling parameter.
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Affiliation(s)
- Arno A Veldhorst
- DNRF Centre "Glass and Time", IMFUFA, Department of Sciences, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark
| | - Jeppe C Dyre
- DNRF Centre "Glass and Time", IMFUFA, Department of Sciences, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark
| | - Thomas B Schrøder
- DNRF Centre "Glass and Time", IMFUFA, Department of Sciences, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark
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16
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Solar M, Paul W. Dielectric α-relaxation of 1,4-polybutadiene confined between graphite walls : Molecular dynamics investigations through numerical simulations of polymer molecules relaxation. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2015; 38:123. [PMID: 25967943 DOI: 10.1140/epje/i2015-15037-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Revised: 03/11/2015] [Accepted: 03/11/2015] [Indexed: 06/04/2023]
Abstract
We present results of Molecular Dynamics (MD) simulations of a chemically realistic model of 1,4-polybutadiene confined by crystalline graphite walls. The simulations cover a large range of temperatures from T ≈ 2T g to T ≈ 1.15T g, where relevant time scales are accessible using such computational methods. We investigate the dielectric relaxation close to the walls in comparison to the one in the center of the film, and study the latter as a function of the film thickness from the walls. The segmental dynamics in the film is slowed down close to the walls, in comparison to the bulk. In addition to the α-process, the relaxation exhibits an additional long time decay, the so-called wall desorption process. We focus here on the α-process and find no significant shift of the dielectric T g as a function of layer thickness, in agreement with recent dielectric experiments. These findings can be correlated with the importance of the dihedral dynamics for all relaxation processes in polymers, which is unaltered except for the first nanometer next to the walls.
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Affiliation(s)
- M Solar
- Institut Charles Sadron (UPR22-CNRS), University of Strasbourg, 23 rue du Loess, BP 84047, F-67034, Strasbourg, France,
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17
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Budzien J, Heffernan JV, McCoy JD. Effect of chain flexibility on master curve behavior for diffusion coefficient. J Chem Phys 2013; 139:244501. [DOI: 10.1063/1.4851437] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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18
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Ngai KL, Habasaki J, Prevosto D, Capaccioli S, Paluch M. Thermodynamic scaling of α-relaxation time and viscosity stems from the Johari-Goldstein β-relaxation or the primitive relaxation of the coupling model. J Chem Phys 2012; 137:034511. [DOI: 10.1063/1.4736547] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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20
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Harmandaris VA, Floudas G, Kremer K. Temperature and Pressure Dependence of Polystyrene Dynamics through Molecular Dynamics Simulations and Experiments. Macromolecules 2010. [DOI: 10.1021/ma102179b] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Vagelis A. Harmandaris
- Department of Applied Mathematics, University of Crete, GR-71110 Heraklion, Greece
- IACM FORTH, GR-71110 Heraklion, Greece
- Max Planck Institute for Polymer Research, D-55128 Mainz, Germany
| | - George Floudas
- Department of Physics, University of Ioannina, GR-45110, Ioannina, Greece
- Foundation for Research and Technology-Biomedical Research Institute, Ioannina, Greece
| | - Kurt Kremer
- Max Planck Institute for Polymer Research, D-55128 Mainz, Germany
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21
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Affiliation(s)
- C. M. Roland
- Naval Research Laboratory, Chemistry Division, Code 6120, Washington, D.C. 20375-5342
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Pawlus S, Sokolov AP, Paluch M, Mierzwa M. Influence of Pressure on Chain and Segmental Dynamics in Polyisoprene. Macromolecules 2010. [DOI: 10.1021/ma100383r] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sebastian Pawlus
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
| | - Alexei P. Sokolov
- Chemical Sciences Division, ORNL, and Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996-1600
| | - Marian Paluch
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
| | - Michal Mierzwa
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
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23
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Coslovich D, Roland CM. Pressure-energy correlations and thermodynamic scaling in viscous Lennard-Jones liquids. J Chem Phys 2009; 130:014508. [DOI: 10.1063/1.3054635] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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24
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Liu J, Wu S, Cao D, Zhang L. Effects of pressure on structure and dynamics of model elastomers: A molecular dynamics study. J Chem Phys 2008; 129:154905. [DOI: 10.1063/1.2996009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Coslovich D, Roland CM. Thermodynamic Scaling of Diffusion in Supercooled Lennard-Jones Liquids. J Phys Chem B 2008; 112:1329-32. [DOI: 10.1021/jp710457e] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- D. Coslovich
- Dipartimento di Fisica Teorica, Università di Trieste, Strada Costiera 11, 34100 Trieste, Italy, and Naval Research Laboratory, Code 6120, Washington, District of Columbia 20375-5342
| | - C. M. Roland
- Dipartimento di Fisica Teorica, Università di Trieste, Strada Costiera 11, 34100 Trieste, Italy, and Naval Research Laboratory, Code 6120, Washington, District of Columbia 20375-5342
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26
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Casalini R, Roland CM, Capaccioli S. Effect of chain length on fragility and thermodynamic scaling of the local segmental dynamics in poly(methylmethacrylate). J Chem Phys 2007; 126:184903. [PMID: 17508828 DOI: 10.1063/1.2728898] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Local segmental relaxation properties of poly(methylmethacrylate) (PMMA) of varying molecular weight are measured by dielectric spectroscopy and analyzed in combination with the equation of state obtained from PVT measurements. Significant variations of glass transition temperature and fragility with molecular weight are observed. In accord with the general properties of glass-forming materials, single molecular weight dependent scaling exponent gamma is sufficient to define the mean segmental relaxation time taualpha and its distribution. This exponent can be connected to the Gruneisen parameter and related thermodynamic quantities, thus demonstrating the interrelationship between dynamics and thermodynamics in PMMA. Changes in the relaxation properties ("dynamic crossover") are observed as a function of both temperature and pressure, with taualpha serving as the control parameter for the crossover. At longer taualpha another change in the dynamics is apparent, associated with a decoupling of the local segmental process from ionic conductivity.
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Affiliation(s)
- R Casalini
- Chemistry Department, George Mason University, Fairfax, Virginia 22030, USA
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27
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Logotheti GE, Theodorou DN. Segmental and Chain Dynamics of Isotactic Polypropylene Melts. Macromolecules 2007. [DOI: 10.1021/ma062234u] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Georgia Evangelia Logotheti
- School of Chemical Engineering, Department of Materials Science and Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus, 15780 Athens, Greece
| | - Doros N. Theodorou
- School of Chemical Engineering, Department of Materials Science and Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus, 15780 Athens, Greece
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28
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Roland CM, Bair S, Casalini R. Thermodynamic scaling of the viscosity of van der Waals, H-bonded, and ionic liquids. J Chem Phys 2006; 125:124508. [PMID: 17014192 DOI: 10.1063/1.2346679] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Viscosities eta and their temperature T and volume V dependences are reported for seven molecular liquids and polymers. In combination with literature viscosity data for five other liquids, we show that the superpositioning of relaxation times for various glass-forming materials when expressed as a function of TV(gamma), where the exponent gamma is a material constant, can be extended to the viscosity. The latter is usually measured to higher temperatures than the corresponding relaxation times, demonstrating the validity of the thermodynamic scaling throughout the supercooled and higher T regimes. The value of gamma for a given liquid principally reflects the magnitude of the intermolecular forces (e.g., steepness of the repulsive potential); thus, we find decreasing gamma in going from van der Waals fluids to ionic liquids. For some strongly H-bonded materials, such as low molecular weight polypropylene glycol and water, the superpositioning fails, due to the nontrivial change of chemical structure (degree of H bonding) with thermodynamic conditions.
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Affiliation(s)
- C M Roland
- Chemistry Division, Naval Research Laboratory, Code 6120, Washington, DC 20375-5342, USA.
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Paul W, Bedrov D, Smith GD. Glass transition in 1,4-polybutadiene: Mode-coupling theory analysis of molecular dynamics simulations using a chemically realistic model. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:021501. [PMID: 17025431 DOI: 10.1103/physreve.74.021501] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Indexed: 05/12/2023]
Abstract
We present molecular dynamics simulations of the glass transition in a chemically realistic model of 1,4-polybutadiene (PBD). Around 40 K above the calorimetric glass transition of this polymer the simulations reveal a well-developed two-stage relaxation of all correlation functions. We have analyzed the time-scale separation between vibrational degrees of freedom (subpicosecond dynamics) and the alpha relaxation behavior (nanosecond to microsecond dynamics) using the predictions of mode-coupling theory (MCT). Our value for the mode-coupling critical temperature Tc agrees perfectly with prior experimental estimates for PBD. The predictions of MCT for the scaling behavior of the so-called beta relaxation, the plateau regime separating vibrational dynamics and the alpha relaxation, are well fulfilled. Furthermore, we are able to derive a consistent set of MCT exponents, completely characterizing the scaling behavior of relaxation processes in the vicinity of Tc. For the temperature dependence of the alpha relaxation we find deviations from MCT predictions which we trace to the influence of torsional barriers on the atomic motions.
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Affiliation(s)
- W Paul
- Institut für Physik, Johannes-Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
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Tsolou G, Harmandaris VA, Mavrantzas VG. Temperature and Pressure Effects on Local Structure and Chain Packing incis-1,4-Polybutadiene from Detailed Molecular Dynamics Simulations. MACROMOL THEOR SIMUL 2006. [DOI: 10.1002/mats.200500088] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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