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Dryzek E, Juszyńska-Gałązka E, Zaleski R, Jasińska B, Eusébio MES. Free volume in the smectic-E phase of 4-hexyl-4' isothiocyanatobiphenyl studied by positron annihilation spectroscopy. Phys Rev E 2020; 101:022705. [PMID: 32168647 DOI: 10.1103/physreve.101.022705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/08/2020] [Indexed: 06/10/2023]
Abstract
Positron annihilation lifetime spectroscopy has been used to study 4-hexyl-4'-isothiocyanatobiphenyl. Changes of the orthopositronium lifetime parameters with temperature have been observed for the supercooled smectic-E phase. The measurements confirm that positronium is created and annihilates in a layer of a lower electron density containing alkyl chains of molecules. The two-state bond-lattice model of glass transition explains the thermal activation of the centers where orthopositronium is created and annihilates when the glass of the smectic-E phase softens. However, the subsequent cold crystallization of the softened regions also influences the orthopositronium lifetime and intensity, which complicates the picture seen by positrons. The measurements during isothermal crystallization suggest that it progresses in two stages. The first stage can be described by the Avrami equation with the Avrami exponent close to unity, which indicates low-dimensional crystallization. Similarly to liquid n alkanes, the application of pressure is equivalent to temperature lowering with the similar equivalence relationship between pressure and temperature, which seems to confirm the structure of the smectic-E phase with sublayers containing alkyl chains in a molten state. The dependence of the orthopositronium lifetime on pressure for the smectic-E phase may be described by the bubble model where the positronium bubble is approximated with a finite square potential well with the depth of U=1.45eV.
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Affiliation(s)
- E Dryzek
- Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Kraków, Poland
| | - E Juszyńska-Gałązka
- Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Kraków, Poland
| | - R Zaleski
- Institute of Physics, Maria Curie-Skłodowska University, Pl. M. Curie-Skłodowskiej 1, 20-031 Lublin, Poland
| | - B Jasińska
- Institute of Physics, Maria Curie-Skłodowska University, Pl. M. Curie-Skłodowskiej 1, 20-031 Lublin, Poland
| | - M E S Eusébio
- CQC Departamento de Quimica, Universidade de Coimbra, Rua Larga 3004-534 Coimbra, Portugal
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Adrjanowicz K, Kaminski K, Koperwas K, Paluch M. Negative Pressure Vitrification of the Isochorically Confined Liquid in Nanopores. PHYSICAL REVIEW LETTERS 2015; 115:265702. [PMID: 26765007 DOI: 10.1103/physrevlett.115.265702] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Indexed: 06/05/2023]
Abstract
Dielectric relaxation studies for model glass-forming liquids confined to nanoporous alumina matrices were examined together with high-pressure results. For confined liquids which show the deviation from bulk dynamics upon approaching the glass transition (the change from the Vogel-Fulcher-Tammann to the Arrhenius law), we have observed a striking agreement between the temperature dependence of the α-relaxation time in the Arrhenius-like region and the isochoric relaxation times extrapolated from the positive range of pressure to the negative pressure domain. Our finding provides strong evidence that glass-forming liquid confined to native nanopores enters the isochoric conditions once the mobility of the interfacial layer becomes frozen in. This results in the negative pressure effects on cooling. We also demonstrate that differences in the sensitivity of various glass-forming liquids to the "confinement effects" can be rationalized by considering the relative importance of thermal energy and density contributions in controlling the α-relaxation dynamics (the E(v)/E(p) ratio).
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Affiliation(s)
- K Adrjanowicz
- Institute of Physics, University of Silesia, ulica Uniwersytecka 4, 40-007 Katowice, Poland
- NanoBioMedical Centre, Adam Mickiewicz University, ulica Umultowska 85, 61-614 Poznan, Poland
| | - K Kaminski
- Institute of Physics, University of Silesia, ulica Uniwersytecka 4, 40-007 Katowice, Poland
- Silesian Center for Education and Interdisciplinary Research, ulica 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - K Koperwas
- Institute of Physics, University of Silesia, ulica Uniwersytecka 4, 40-007 Katowice, Poland
- Silesian Center for Education and Interdisciplinary Research, ulica 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - M Paluch
- Institute of Physics, University of Silesia, ulica Uniwersytecka 4, 40-007 Katowice, Poland
- Silesian Center for Education and Interdisciplinary Research, ulica 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
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Beichel W, Yu Y, Dlubek G, Krause-Rehberg R, Pionteck J, Pfefferkorn D, Bulut S, Bejan D, Friedrich C, Krossing I. Free volume in ionic liquids: a connection of experimentally accessible observables from PALS and PVT experiments with the molecular structure from XRD data. Phys Chem Chem Phys 2013; 15:8821-30. [DOI: 10.1039/c3cp43306d] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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López ER, Pensado AS, Fernández J, Harris KR. On the density scaling of pVT data and transport properties for molecular and ionic liquids. J Chem Phys 2012; 136:214502. [DOI: 10.1063/1.4720070] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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Feldstein MM, Siegel RA. Molecular and nanoscale factors governing pressure-sensitive adhesion strength of viscoelastic polymers. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/polb.23065] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Yu Y, Beichel W, Dlubek G, Krause-Rehberg R, Paluch M, Pionteck J, Pfefferkorn D, Bulut S, Friedrich C, Pogodina N, Krossing I. Free volume and phase transitions of 1-butyl-3-methylimidazolium based ionic liquids from positron lifetime spectroscopy. Phys Chem Chem Phys 2012; 14:6856-68. [DOI: 10.1039/c2cp40486a] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Papathanassiou AN, Sakellis I, Grammatikakis J, Roland CM. The role of the isothermal bulk modulus in the molecular dynamics of super-cooled liquids. J Chem Phys 2011; 135:244508. [PMID: 22225170 DOI: 10.1063/1.3666008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Elastic models imply that the energy expended for a flow event in ultra-viscous matter coincides with the elastic work required for deforming and re-arranging the environment of the moving entity. This is quite promising for explaining the strong non-Arrhenius behavior of dynamic quantities of fragile super-cooled liquids. We argue that the activation volume obtained from dielectric relaxation and light-scattering experiments for super-cooled liquids should scale with the Gibbs free energy of activation, with a proportionality constant determined by the isothermal bulk modulus and its pressure derivative, as described by an earlier thermodynamic elastic model. For certain super-cooled liquids the bulk compression transpiring in the local environment, as governed by the isothermal bulk modulus, play a significant role in the reorientational dynamics, with far-field density fluctuations and volume changes avoided by shear deformation.
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Bartoš J, Iskrová M, Köhler M, Wehn R, Sauša O, Lunkenheimer P, Krištiak J, Loidl A. Positron annihilation response and broadband dielectric spectroscopy: salol. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2011; 34:104. [PMID: 21947898 DOI: 10.1140/epje/i2011-11104-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 06/14/2011] [Accepted: 07/21/2011] [Indexed: 05/31/2023]
Abstract
A phenomenological analysis of the ortho-positronium (o-Ps) annihilation from positron annihilation lifetime spectroscopy (PALS) and the dynamics from broadband dielectric spectroscopy (BDS) are reported on a small molecular glass former of intermediate H-bonding and fragility: salol. The dielectric spectra extend over a very broad frequency range of about 2 × 10(-2)-3.5 × 10(11) Hz, providing information on the α-relaxation, the secondary relaxation giving rise to the excess wing, and the shallow high-frequency minimum in the micro- to milli-meter wave range. A number of empirical correlations between the o-Ps lifetime, τ(3)(T), and the various spectral and relaxation features have been observed. Thus, the phenomenological evaluation of the τ(3)(T) dependence of the PALS response of the amorphous sample reveals three characteristic PALS temperatures: T(g)(PALS), T(b1)(L) = 1.15T(g)(PALS) and T(b2)(L) = 1.25T(g)(PALS), which are discussed in relation to similar findings for some typical small molecular vdW- and H-bonded glass formers. A slighter change of the slope at T(b1)(L) appears to be related to the transition from excess wing to the primary α-process-dominated behavior, with the secondary process dominating in the deeply supercooled liquid state below T(b1)(L). The high-temperature plateau effect in the τ (3)(T) plot occurs at T(b2)(L) and agrees with the characteristic Stickel temperature, T(B)(ST), marking a qualitative change of the primary α process, but it does not follow the relation T(b2)(L) < T(α) [τ(3)(T(b2)) < τ(α)]. Both effects at T(b1)(L) and T(b2)(L) correlate with two crossovers in the spectral shape and related non-exponentiality parameter of the structural relaxation, β (KWW). Finally, the application of the two-order parameter (TOP) model to the structural relaxation as represented by the primary α relaxation times from BDS leads to the characteristic TOP temperature, T(m)(c), close to T(b1) from PALS. Within this model the phenomenological interpretation is offered based on changes in the probability of occurrence of solid-like and liquid-like domains to explain the dynamic as well as PALS responses. In summary, all the empirical correlations support further very close connections between the PALS response and the dielectric relaxation behavior in small molecule glass formers.
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Affiliation(s)
- J Bartoš
- Polymer Institute of SAS, Dúbravská cesta 9, SK - 845 41 Bratislava, Slovak Republic.
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Dlubek G, Shaikh MQ, Rätzke K, Pionteck J, Paluch M, Faupel F. Subnanometre size free volumes in amorphous Verapamil hydrochloride: A positron lifetime and PVT study through Tg in comparison with dielectric relaxation spectroscopy. Eur J Pharm Sci 2010; 41:388-98. [DOI: 10.1016/j.ejps.2010.07.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 07/07/2010] [Accepted: 07/12/2010] [Indexed: 11/25/2022]
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Dlubek G, Yu Y, Krause-Rehberg R, Beichel W, Bulut S, Pogodina N, Krossing I, Friedrich C. Free volume in imidazolium triflimide ([C3MIM][NTf2]) ionic liquid from positron lifetime: Amorphous, crystalline, and liquid states. J Chem Phys 2010; 133:124502. [PMID: 20886945 DOI: 10.1063/1.3487522] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
- G Dlubek
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle, Germany.
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Dlubek G, Shaikh MQ, Rätzke K, Paluch M, Faupel F. Free volume from positron lifetime and pressure-volume-temperature experiments in relation to structural relaxation of van der Waals molecular glass-forming liquids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:235104. [PMID: 21393763 DOI: 10.1088/0953-8984/22/23/235104] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Positron annihilation lifetime spectroscopy (PALS) is employed to characterize the temperature dependence of the free volume in two van der Waals liquids: 1, 1'-bis(p-methoxyphenyl)cyclohexane (BMPC) and 1, 1'-di(4-methoxy-5-methylphenyl)cyclohexane (BMMPC). From the PALS spectra analysed with the routine LifeTime9.0, the size (volume) distribution of local free volumes (subnanometer size holes), its mean, [v(h)], and mean dispersion, σ(h), were calculated. A comparison with the macroscopic volume from pressure-volume-temperature (PV T) experiments delivered the hole density and the specific hole free volume and a complete characterization of the free volume microstructure in that sense. These data are used in correlation with structural (α) relaxation data from broad-band dielectric spectroscopy (BDS) in terms of the Cohen-Grest and Cohen-Turnbull free volume models. An extension of the latter model allows us to quantify deviations between experiments and theory and an attempt to systematize these in terms of T(g) or of the fragility. The experimental data for several fragile and less fragile glass formers are involved in the final discussion. It was concluded that, for large differences in the fragility of different glass formers, the positron lifetime mirrors clearly the different character of these materials. For small differences in the fragility, additional properties like the character of bonds and chemical structure of the material may affect size, distribution and thermal behaviour of the free volume.
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Affiliation(s)
- G Dlubek
- ITA Institute for Innovative Technologies, Köthen/Halle, Wiesenring 4, D-06120 Lieskau, Germany.
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