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Al Lafi AG. Structural development in ion-irradiated poly(ether ether ketone) as studied by dielectric relaxation spectroscopy. J Appl Polym Sci 2013. [DOI: 10.1002/app.39929] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Abdul G. Al Lafi
- Department of Chemistry; Atomic Energy Commission; P. O. Box 6091 Damascus Syrian Arab Republic
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Adrjanowicz K, Kaminski K, Wlodarczyk P, Grzybowska K, Tarnacka M, Zakowiecki D, Garbacz G, Paluch M, Jurga S. Molecular Dynamics of the Supercooled Pharmaceutical Agent Posaconazole Studied via Differential Scanning Calorimetry and Dielectric and Mechanical Spectroscopies. Mol Pharm 2013; 10:3934-45. [DOI: 10.1021/mp4003915] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- K. Adrjanowicz
- NanoBioMedical
Centre, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznan, Poland
| | - K. Kaminski
- Institute
of Physics, University of Silesia, ul. Uniwersytecka 4, 40-007 Katowice, Poland
| | - P. Wlodarczyk
- Institute of Non-Ferrous Metals, ul. Sowinskiego 5, 44-100 Gliwice, Poland
| | - K. Grzybowska
- Institute
of Physics, University of Silesia, ul. Uniwersytecka 4, 40-007 Katowice, Poland
| | - M. Tarnacka
- Institute
of Physics, University of Silesia, ul. Uniwersytecka 4, 40-007 Katowice, Poland
| | - D. Zakowiecki
- Pharmaceutical Works “Polpharma”, Pelpińska 19, 83-200 Starogard Gdański, Poland
| | - G. Garbacz
- University of Greifswald, Institute of Pharmacy, Friedrich-Ludwig-Jahn-Strasse 17, Greifswald, Germany
| | - M. Paluch
- Institute
of Physics, University of Silesia, ul. Uniwersytecka 4, 40-007 Katowice, Poland
| | - S. Jurga
- NanoBioMedical
Centre, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznan, Poland
- Department
of Macromolecular Physics, Adam Mickiewicz University, ul. Umultowska
85, 61-614 Poznan, Poland
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Trachenko K, Roland CM, Casalini R. Relationship between the Nonexponentiality of Relaxation and Relaxation Time in the Problem of Glass Transition. J Phys Chem B 2008; 112:5111-5. [DOI: 10.1021/jp800347w] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- K. Trachenko
- Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, U.K., Naval Research Laboratory, Washington, District of Columbia 20375-5342, and George Mason University, Fairfax, Virginia 22030
| | - C. M. Roland
- Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, U.K., Naval Research Laboratory, Washington, District of Columbia 20375-5342, and George Mason University, Fairfax, Virginia 22030
| | - R. Casalini
- Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, U.K., Naval Research Laboratory, Washington, District of Columbia 20375-5342, and George Mason University, Fairfax, Virginia 22030
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Kunal K, Paluch M, Roland CM, Puskas JE, Chen Y, Sokolov AP. Polyisobutylene: A most unusual polymer. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/polb.21473] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Casalini R, Roland CM. Comment on "Correlations between isobaric and isochoric fragilities and thermodynamical scaling exponent for glass-forming liquids". PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 76:013501; author reply 013502. [PMID: 17677518 DOI: 10.1103/physreve.76.013501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Indexed: 05/16/2023]
Abstract
For nonassociated, glass-forming liquids and polymers, thermodynamic scaling of structural relaxation times and viscosities is an empirical fact, demonstrated by various groups for dozens of materials. The P and T invariance of the isochoric fragility follows directly from this scaling. Apparent inconsistencies with these statements were reported recently by Grzybowski [A. Grzybowski, K. Grzybowska, J. Zioło, and M. Paluch, Phys. Rev. E 74, 041503 (2006)]; however, the putative inconsistencies arise from use at higher pressures of parameters to correlate the isobaric and isochoric fragilities that are valid only for ambient pressure.
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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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Ngai KL, Casalini R, Capaccioli S, Paluch M, Roland CM. Do Theories of the Glass Transition, in which the Structural Relaxation Time Does Not Define the Dispersion of the Structural Relaxation, Need Revision? J Phys Chem B 2005; 109:17356-60. [PMID: 16853218 DOI: 10.1021/jp053439s] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Upon decreasing temperature or increasing pressure, a noncrystallizing liquid will vitrify; that is, the structural relaxation time, taualpha, becomes so long that the system cannot attain an equilibrium configuration in the available time. Theories, including the well-known free volume and configurational entropy models, explain the glass transition by invoking a single quantity that governs the structural relaxation time. The dispersion of the structural relaxation (i.e., the structural relaxation function) is either not addressed or is derived as a parallel consequence (or afterthought) and thus is independent of taualpha. In these models the time dependence of the relaxation bears no fundamental relationship to the value of taualpha or other dynamic properties. Such approaches appear to be incompatible with a general experimental fact recently discovered in glass-formers: for a given material at a fixed value of taualpha, the dispersion is constant, independent of thermodynamic conditions (T and P); that is, the shape of the alpha-relaxation function depends only on the relaxation time. If derived independently of taualpha, it is an unlikely result that the dispersion of the structural relaxation would be uniquely defined by taualpha.
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Affiliation(s)
- K L Ngai
- Naval Research Laboratory, Washington D.C. 20375-5320, Chemistry Department, George Mason University, Fairfax, Virginia, USA
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Roland CM, Casalini R. Effect of chemical structure on the isobaric and isochoric fragility in polychlorinated biphenyls. J Chem Phys 2005; 122:134505. [PMID: 15847479 DOI: 10.1063/1.1863173] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Pressure-volume-temperature data, along with dielectric relaxation measurements, are reported for a series of polychlorinated biphenyls (PCB), differing in the number of chlorine atoms on their phenyl rings. Analysis of the results reveals that with increasing chlorine content, the relaxation times of the PCB become governed to a greater degree by density rho relative to the effect of temperature T. This result is consistent with the respective magnitudes of the scaling exponent gamma yielding superpositioning of the relaxation times measured at various temperatures and pressures, when plotted versus rho(gamma)/T. While at constant (atmospheric) pressure, fragilities for the various PCB are equivalent, the fragility at constant volume varies inversely with chlorine content. Evidently, the presence of bulkier chlorine atoms on the phenyl rings magnifies the effect which the density has on the relaxation dynamics.
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Affiliation(s)
- C M Roland
- Naval Research Laboratory, Chemistry Division, Code 6120, Washington, DC 20375-5342, USA.
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Maślanka S, Paluch M, Sułkowski WW, Roland CM. Primary and secondary relaxations in bis-5-hydroxypentylphthalate. J Chem Phys 2005; 122:84511. [PMID: 15836067 DOI: 10.1063/1.1851980] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Broadband dielectric spectroscopy was used to study the relaxation dynamics in bis-5-hydroxypentylphthalate (BHPP) under both isobaric and isothermal conditions. The relaxation dynamics exhibit complex behavior, arising from hydrogen bonding in the BHPP. At ambient pressure above the glass transition temperature T(g), the dielectric spectrum shows a broad structural relaxation peak with a prominent excess wing toward higher frequencies. As temperature is decreased below T(g), the excess wing transforms into two distinct peaks, both having Arrhenius behavior with activation energies equal to 58.8 and 32.6 kJmol for slower (beta) and faster (gamma) processes, respectively. Furthermore, the relaxation times for the beta process increase with increasing pressure, whereas the faster gamma relaxation is practically insensitive to pressure changes. Analysis of the properties of these secondary relaxations suggests that the beta peak can be identified as an intermolecular Johari-Goldstein (JG) process. However, its separation in frequency from the alpha relaxation, and both its activation energy and activation volume, differ substantially from values calculated from the breadth of the structural relaxation peak. Thus, the dynamics of BHPP appear to be an exception to the usual correlation between the respective properties of the structural and the JG secondary relaxations.
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Affiliation(s)
- S Maślanka
- Institute of Chemistry, Szkolna 9, 40-006 Katowice, Poland
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Scaling of the segmental relaxation times of polymers and its relation to the thermal expansivity. Colloid Polym Sci 2004. [DOI: 10.1007/s00396-004-1156-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Roland CM, Capaccioli S, Lucchesi M, Casalini R. Adam–Gibbs model for the supercooled dynamics in the ortho-terphenyl ortho-phenylphenol mixture. J Chem Phys 2004; 120:10640-6. [PMID: 15268090 DOI: 10.1063/1.1739394] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Dielectric measurements of the alpha-relaxation time were carried out on a mixture of ortho-terphenyl (OTP) with ortho-phenylphenol, over a range of temperatures at two pressures, 0.1 and 28.8 MPa. These are the same conditions for which heat capacity, thermal expansivity, and compressibility measurements were reported by Takahara et al. [S. Takahara, M. Ishikawa, O. Yamamuro, and T. Matsuo, J. Phys. Chem. B 103, 3288 (1999)] for the same mixture. From the combined dynamic and thermodynamic data, we determine that density and temperature govern to an equivalent degree the variation of the relaxation times with temperature. Over the measured range, the dependence of the relaxation times on configurational entropy is in accord with the Adam-Gibbs model, and this dependence is invariant to pressure. Consistent with the implied connection between relaxation and thermodynamic properties, the kinetic and thermodynamic fragilities are found to have the same pressure independence. In comparing the relaxation properties of the mixture to those of neat OTP, density effects are stronger in the former, perhaps suggestive of less efficient packing.
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Affiliation(s)
- C M Roland
- Naval Research Laboratory, Chemistry Division, Code 6120, Washington, DC 20375-5342, USA.
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Robertson CG, Roland CM. Local segmental relaxation in bidisperse polystyrenes. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/polb.20127] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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