1
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Drzewicz A, Jasiurkowska-Delaporte M, Kula P, Juszyńska-Gałązka E. Effect of the linking bridge type on the self-assembly behaviour of 2',3'-difluoroterphenyl derivatives. Phys Chem Chem Phys 2024; 26:8748-8760. [PMID: 38416415 DOI: 10.1039/d4cp00133h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
The self-assembly behaviour and the crystallization kinetics of two liquid crystal compounds containing 2',3'-difluorosubstituted terphenyl as the mesogenic core have been described. Calorimetric studies show that the linking bridge type affects the polymorphism of smectic phases. The CH2O.3 compound with the -CH2O- linking bridge connected with a longer methylene spacer possesses the chiral smectic phase with antiferroelectric properties (SmCA* phase), while the COO.6 liquid crystal with the -COO- linking bridge connected with a shorter alkyl chain forms the chiral smectic phase with ferroelectric properties (SmC* phase). Both compounds crystallize upon slow cooling, while fast cooling causes the vitrification of the conformationally disordered crystal phase. Dielectric measurements reveal the complex relaxation dynamics in the identified thermodynamic states. DFT calculations allow us to estimate the nature of relaxation processes.
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Affiliation(s)
- Anna Drzewicz
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Krakow, Poland.
| | | | - Przemysław Kula
- Institute of Chemistry, Military University of Technology, PL-00908 Warszawa, Poland
| | - Ewa Juszyńska-Gałązka
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Krakow, Poland.
- Research Center for Thermal and Entropic Science, Graduate School of Science, Osaka University, 560-0043 Osaka, Japan
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2
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Caporaletti F, Napolitano S. The slow Arrhenius process in small organic molecules. Phys Chem Chem Phys 2024; 26:745-748. [PMID: 38053485 DOI: 10.1039/d3cp05044k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Equilibration, the complex set of molecular rearrangements leading to more stable states, is usually dominated by density fluctuations, occurring through the structural (α-)relaxation, whose timescale quickly increases upon cooling. Growing evidence shows, however, that equilibration can be reached also through an alternative pathway provided by the Slow Arrhenius process (SAP), a molecular mode slower than the structural processes in the liquid state and faster in glass. The SAP, widely observed in polymers, has not yet been reported in small molecules, probably because of the larger experimental difficulties in handling these systems. Here, we report the presence of the SAP in three different molecular glassformers, by investigating these systems in the thin film geometry via dielectric spectroscopy. These results reinforce the idea that the SAP is a universal feature of liquid and glassy dynamics.
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Affiliation(s)
- Federico Caporaletti
- Laboratory of Polymer and Soft Matter Dynamics, Experimental Soft Matter and Thermal Physics (EST), Université libre de Bruxelles (ULB), Brussels 1050, Belgium.
| | - Simone Napolitano
- Laboratory of Polymer and Soft Matter Dynamics, Experimental Soft Matter and Thermal Physics (EST), Université libre de Bruxelles (ULB), Brussels 1050, Belgium.
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3
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Hellwig H, Nowok A, Peksa P, Dulski M, Musioł R, Pawlus S, Kuś P. Molecular Dynamics and Near- Tg Phenomena of Cyclic Thioethers. Int J Mol Sci 2023; 24:17166. [PMID: 38138995 PMCID: PMC10742681 DOI: 10.3390/ijms242417166] [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: 10/30/2023] [Revised: 11/20/2023] [Accepted: 12/02/2023] [Indexed: 12/24/2023] Open
Abstract
This article presents the synthesis and molecular dynamics investigation of three novel cyclic thioethers: 2,3-(4'-methylbenzo)-1,4,7,10-tetrathiacyclododeca-2-ene (compound 1), 2,3,14,15-bis(4',4″(5″)-methylbenzo)-1,4,7,10,13,16,19,22,25-octathiacyclotetracosa-2,14-diene (compound 2), and 2,3,8,9-bis(4',4″(5″)-methylbenzo)-1,4,7,10-tetrathiacyclododeca-2,8-diene (compound 3). The compounds exhibit relatively high glass transition temperatures (Tg), which range between 254 and 283 K. This characteristic positions them within the so-far limited category of crown-like glass-formers. We demonstrate that cyclic thioethers may span both the realms of ordinary and sizeable molecular glass-formers, each featuring distinct physical properties. Furthermore, we show that the Tg follows a sublinear power law as a function of the molar mass within this class of compounds. We also reveal multiple dielectric relaxation processes of the novel cyclic thioethers. Above the Tg, their dielectric loss spectra are dominated by a structural relaxation, which originates from the cooperative reorientation of entire molecules and exhibits an excess wing on its high-frequency slope. This feature has been attributed to the Johari-Goldstein (JG) process. Each investigated compound exhibits also at least one intramolecular secondary non-JG relaxation stemming from conformational changes. Their activation energies range from approximately 19 kJ/mol to roughly 40 kJ/mol. Finally, we analyze the high-pressure molecular dynamics of compound 1, revealing a pressure-induced increase in its Tg with a dTg/dp coefficient equal to 197 ± 8 K/GPa.
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Affiliation(s)
- Hubert Hellwig
- Center for Integrated Technology and Organic Synthesis (CiTOS), MolSys Research Unit, University of Liège, B6a, Room 3/19, Allée du Six Août 13, 4000 Liege, Belgium;
| | - Andrzej Nowok
- Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Stanisława Wyspiańskiego 27, 50-370 Wrocław, Poland; (A.N.); (P.P.)
| | - Paulina Peksa
- Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Stanisława Wyspiańskiego 27, 50-370 Wrocław, Poland; (A.N.); (P.P.)
| | - Mateusz Dulski
- Faculty of Science and Technology, Institute of Materials Engineering, University of Silesia in Katowice, 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland;
| | - Robert Musioł
- Institute of Chemistry, University of Silesia in Katowice, Szkolna 9, 40-003 Katowice, Poland;
| | - Sebastian Pawlus
- August Chełkowski Institute of Physics, University of Silesia in Katowice, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland;
| | - Piotr Kuś
- Institute of Chemistry, University of Silesia in Katowice, Szkolna 9, 40-003 Katowice, Poland;
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4
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Song L, Gao Y, Zou P, Xu W, Gao M, Zhang Y, Huo J, Li F, Qiao J, Wang LM, Wang JQ. Detecting the exponential relaxation spectrum in glasses by high-precision nanocalorimetry. Proc Natl Acad Sci U S A 2023; 120:e2302776120. [PMID: 37155861 PMCID: PMC10193961 DOI: 10.1073/pnas.2302776120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 04/16/2023] [Indexed: 05/10/2023] Open
Abstract
Nonexponential relaxations are universal characteristics for glassy materials. There is a well-known hypothesis that nonexponential relaxation peaks are composed of a series of exponential events, which have not been verified. In this Letter, we discover the exponential relaxation events during the recovery process using a high-precision nanocalorimetry, which are universal for metallic glasses and organic glasses. The relaxation peaks can be well fitted by the exponential Debye function with a single activation energy. The activation energy covers a broad range from α relaxation to β relaxation and even the fast γ/β' relaxation. We obtain the complete spectrum of the exponential relaxation peaks over a wide temperature range from 0.63Tg to 1.03Tg, which provides solid evidence that nonexponential relaxation peaks can be decomposed into exponential relaxation units. Furthermore, the contribution of different relaxation modes in the nonequilibrium enthalpy space is measured. These results open a door for developing the thermodynamics of nonequilibrium physics and for precisely modulating the properties of glasses by controlling the relaxation modes.
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Affiliation(s)
- Lijian Song
- Key Laboratory of Magnetic Materials and Devices, and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo315201, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
| | - Yurong Gao
- Key Laboratory of Magnetic Materials and Devices, and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo315201, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
| | - Peng Zou
- Key Laboratory of Magnetic Materials and Devices, and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo315201, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
| | - Wei Xu
- Key Laboratory of Magnetic Materials and Devices, and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo315201, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
| | - Meng Gao
- Key Laboratory of Magnetic Materials and Devices, and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo315201, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
| | - Yan Zhang
- Key Laboratory of Magnetic Materials and Devices, and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo315201, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
| | - Juntao Huo
- Key Laboratory of Magnetic Materials and Devices, and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo315201, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
| | - Fushan S. Li
- School of Materials Science and Engineering, Zhengzhou University, Zhengzhou450001, China
| | - Jichao C. Qiao
- School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University, Xian710072, China
| | - Li-Min Wang
- State Key Laboratory of Metastable Materials Science and Technology, and College of Materials Science and Engineering, Yanshan University, Qinhuangdao, Hebei066004, China
| | - Jun-Qiang Wang
- Key Laboratory of Magnetic Materials and Devices, and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo315201, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
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5
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Heczko D, Tarnacka M, Kamiński K, Paluch M, Kamińska E. Breakdown of isochronal superpositioning of α- and β-relaxation times in the van der Waals system – loratadine. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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6
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Kinetics of cold crystallization in two liquid crystalline fluorinated homologues exhibiting the vitrified smectic CA* phase. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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7
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Singh LP. Primary and secondary relaxation processes in poly(propylene glycol) monobutyl ether: a broadband dielectric spectroscopy investigation. Polym J 2022. [DOI: 10.1038/s41428-022-00728-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Xu X, Douglas JF, Xu WS. Thermodynamic–Dynamic Interrelations in Glass-Forming Polymer Fluids. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xiaolei Xu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Wen-Sheng Xu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
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9
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Simple Rules for Complex Near-Glass-Transition Phenomena in Medium-Sized Schiff Bases. Int J Mol Sci 2022; 23:ijms23095185. [PMID: 35563574 PMCID: PMC9103181 DOI: 10.3390/ijms23095185] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 05/01/2022] [Accepted: 05/03/2022] [Indexed: 02/04/2023] Open
Abstract
Glass-forming ability is one of the most desired properties of organic compounds dedicated to optoelectronic applications. Therefore, finding general structure–property relationships and other rules governing vitrification and related near-glass-transition phenomena is a burning issue for numerous compound families, such as Schiff bases. Hence, we employ differential scanning calorimetry, broadband dielectric spectroscopy, X-ray diffraction and quantum density functional theory calculations to investigate near-glass-transition phenomena, as well as ambient- and high-pressure molecular dynamics for two structurally related Schiff bases belonging to the family of glycine imino esters. Firstly, the surprising great stability of the supercooled liquid phase is shown for these compounds, also under high-pressure conditions. Secondly, atypical self-organization via bifurcated hydrogen bonds into lasting centrosymmetric dimers is proven. Finally, by comparing the obtained results with the previous report, some general rules that govern ambient- and high-pressure molecular dynamics and near-glass transition phenomena are derived for the family of glycine imino esters. Particularly, we derive a mathematical formula to predict and tune their glass transition temperature (Tg) and its pressure coefficient (dTg/dp). We also show that, surprisingly, despite the presence of intra- and intermolecular hydrogen bonds, van der Waals and dipole–dipole interactions are the main forces governing molecular dynamics and dielectric properties of glycine imino esters.
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10
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Song Z, Rodríguez-Tinoco C, Mathew A, Napolitano S. Fast equilibration mechanisms in disordered materials mediated by slow liquid dynamics. SCIENCE ADVANCES 2022; 8:eabm7154. [PMID: 35427165 PMCID: PMC9012462 DOI: 10.1126/sciadv.abm7154] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 03/01/2022] [Indexed: 06/14/2023]
Abstract
The rate at which a nonequilibrium system decreases its free energy is commonly ascribed to molecular relaxation processes, arising from spontaneous rearrangements at the microscopic scale. While equilibration of liquids usually requires density fluctuations at time scales quickly diverging upon cooling, growing experimental evidence indicates the presence of a different, alternative pathway of weaker temperature dependence. Such equilibration processes exhibit a temperature-invariant activation energy, on the order of 100 kJ mol-1. Here, we identify the underlying molecular process responsible for this class of Arrhenius equilibration mechanisms with a slow mode (SAP), universally observed in the liquid dynamics of thin films. The SAP, which we show is intimately connected to high-temperature flow, can efficiently drive melts and glasses toward more stable, less energetic states. Our results show that measurements of liquid dynamics can be used to predict the equilibration rate in the glassy state.
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11
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Heczko D, Jesionek P, Hachuła B, Jurkiewicz K, Grelska J, Tarnacka M, Kamiński K, Paluch M, Kamińska E. Variation in the local ordering, H-bonding pattern and molecular dynamics in the pressure densified ritonavir. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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12
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Drzewicz A, Jasiurkowska-Delaporte M, Juszyńska-Gałązka E, Deptuch A, Gałązka M, Zając W, Drzewiński W. On relaxation and vibrational dynamics in the thermodynamic states of a chiral smectogenic glass-former. Phys Chem Chem Phys 2022; 24:4595-4612. [PMID: 35132977 DOI: 10.1039/d1cp05048f] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This article shows the full characteristics (i.e., the phase situation as well as the relaxation and vibrational dynamics) of the (S)-4'-(1-methyloctyloxycarbonyl)biphenyl-4-yl 4-[5-(2,2,3,3,4,4,4-heptafluorobutoxy)pentyl-1-oxy]-benzoate chiral liquid crystal. Besides two enantiotropic chiral smectic phases (SmC* and ), the compound under study also forms the hexatic smectic phase and two crystal phases (Cr1 and Cr2). The XRD patterns imply a similar structure of both crystal phases. The sample crystallizes upon slow cooling, while the phase undergoes a glass transition during fast cooling. Upon subsequent heating, cold crystallization is observed. Our research reveals the complex relaxation dynamics in the identified thermodynamic states, e.g., two relaxations up to the beginning of cold crystallization, three modes in the crystal phases and seven processes in all smectic phases. The results from the scaling of the dielectric response indicate that the origin of the dynamics and behavior of the dielectric permittivity is the same for all phases, regardless of the change in temperature and/or external biasing field. The high value of the fragility index (mf ≈ 146) indicates that the compound under study is a fragile glass-forming system. The region of the -COO- and -COC- group stretching vibrations is primarily sensitive to the structural changes occurring during phase transitions.
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Affiliation(s)
- Anna Drzewicz
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Kraków, Poland.
| | | | - Ewa Juszyńska-Gałązka
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Kraków, Poland. .,Osaka University, 565-0871 Osaka, Japan
| | - Aleksandra Deptuch
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Kraków, Poland.
| | - Mirosław Gałązka
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Kraków, Poland.
| | - Wojciech Zając
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Kraków, Poland.
| | - Witold Drzewiński
- Institute of Chemistry, Military University of Technology, PL-00908 Warszawa, Poland
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13
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Nowok A, Cieślik W, Dulski M, Jurkiewicz K, Grelska J, Alemán J, Musioł R, Szeremeta AZ, Pawlus S. Glass-forming Schiff bases: Peculiar self-organizing systems with bifurcated hydrogen bonds. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Deptuch A, Lalik S, Jasiurkowska-Delaporte M, Juszyńska-Gałązka E, Drzewicz A, Urbańska M, Marzec M. Comparative study of electrooptic, dielectric, and structural properties of two glassforming antiferroelectric mixtures with a high tilt angle. Phys Rev E 2022; 105:024705. [PMID: 35291092 DOI: 10.1103/physreve.105.024705] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 02/06/2022] [Indexed: 06/14/2023]
Abstract
Vitrification of the antiferroelectric smectic-C_{A}^{*} phase is reported for the orthoconic mixture W-1000 and its new derivative W-356. The crystallization is not observed even upon slow cooling and the cold crystallization on subsequent heating is also absent. Molecular dynamics in the smectic phases of both mixtures is investigated down to 173 K and the fragility parameters are determined from the temperature behavior of the α-process. X-ray diffraction is applied to compare the structural parameters of W-356 and W-1000 as well as to study the structural changes during the glass transition of the Sm-C_{A}^{*} phase. The evolution of the smectic layer order within the Sm-C_{A}^{*} glass is reported, while the correlation length of the short-range order in the smectic layers is shown to be almost constant below the glass transition temperature. Electrooptic properties of W-356: spontaneous polarization, tilt angle and switching time are determined and compared with these of W-1000. The observed differences between the properties of W-356 and W-1000 might be explained by the dimer formation of components with the -C≡N terminal group, present only in the W-356 mixture, and by the different structure of the aromatic molecular core in one of the W-356 components.
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Affiliation(s)
- Aleksandra Deptuch
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152, PL-31342 Kraków, Poland
| | - Sebastian Lalik
- M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, PL-30348 Kraków, Poland
| | | | - Ewa Juszyńska-Gałązka
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152, PL-31342 Kraków, Poland
| | - Anna Drzewicz
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152, PL-31342 Kraków, Poland
| | - Magdalena Urbańska
- Institute of Chemistry, Military University of Technology, Kaliskiego 2, PL-00908 Warsaw, Poland
| | - Monika Marzec
- M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, PL-30348 Kraków, Poland
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15
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TSDC and DSC investigation on the molecular mobility in the amorphous solid state and in the glass transformation region of two benzodiazepine derivatives: diazepam and nordazepam. J Pharm Sci 2022; 111:2239-2248. [DOI: 10.1016/j.xphs.2022.02.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/22/2022] [Accepted: 02/22/2022] [Indexed: 11/22/2022]
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16
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Raistrick T, Reynolds M, Gleeson HF, Mattsson J. Influence of Liquid Crystallinity and Mechanical Deformation on the Molecular Relaxations of an Auxetic Liquid Crystal Elastomer. Molecules 2021; 26:7313. [PMID: 34885896 PMCID: PMC8659252 DOI: 10.3390/molecules26237313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 11/23/2022] Open
Abstract
Liquid Crystal Elastomers (LCEs) combine the anisotropic ordering of liquid crystals with the elastic properties of elastomers, providing unique physical properties, such as stimuli responsiveness and a recently discovered molecular auxetic response. Here, we determine how the molecular relaxation dynamics in an acrylate LCE are affected by its phase using broadband dielectric relaxation spectroscopy, calorimetry and rheology. Our LCE is an excellent model system since it exhibits a molecular auxetic response in its nematic state, and chemically identical nematic or isotropic samples can be prepared by cross-linking. We find that the glass transition temperatures (Tg) and dynamic fragilities are similar in both phases, and the T-dependence of the α relaxation shows a crossover at the same T* for both phases. However, for T>T*, the behavior becomes Arrhenius for the nematic LCE, but only more Arrhenius-like for the isotropic sample. We provide evidence that the latter behavior is related to the existence of pre-transitional nematic fluctuations in the isotropic LCE, which are locked in by polymerization. The role of applied strain on the relaxation dynamics and mechanical response of the LCE is investigated; this is particularly important since the molecular auxetic response is linked to a mechanical Fréedericksz transition that is not fully understood. We demonstrate that the complex Young's modulus and the α relaxation time remain relatively unchanged for small deformations, whereas for strains for which the auxetic response is achieved, significant increases are observed. We suggest that the observed molecular auxetic response is coupled to the strain-induced out-of-plane rotation of the mesogen units, in turn driven by the increasing constraints on polymer configurations, as reflected in increasing elastic moduli and α relaxation times; this is consistent with our recent results showing that the auxetic response coincides with the emergence of biaxial order.
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Affiliation(s)
| | | | | | - Johan Mattsson
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK; (T.R.); (M.R.); (H.F.G.)
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17
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Diogo HP, Moura Ramos JJ. Dielectric relaxation study of poly (ether imide) by thermally stimulated depolarization currents. J Appl Polym Sci 2021. [DOI: 10.1002/app.51568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Hermínio P. Diogo
- Centro de Química Estrutural, Complexo I, Instituto Superior Técnico Universidade de Lisboa Lisbon Portugal
| | - Joaquim J. Moura Ramos
- Centro de Química Estrutural, Complexo I, Instituto Superior Técnico Universidade de Lisboa Lisbon Portugal
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18
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Yang Q, Pei CQ, Yu HB, Feng T. Metallic Nanoglasses with Promoted β-Relaxation and Tensile Plasticity. NANO LETTERS 2021; 21:6051-6056. [PMID: 34240612 DOI: 10.1021/acs.nanolett.1c01283] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The secondary (β) relaxation is an intrinsic feature of glassy systems and is crucial for the mechanical properties of metallic glasses. However, it remains puzzling what structural features control the β-relaxation fundamentally. Here, we use the recently developed nanoglasses exhibiting well-defined structural features at the nanometer scale to interrogate such structure-dynamics relations. We show that an electrodeposited Ni77.5P22.5 nanoglass exhibits promoted β-relaxation and enhanced microscale tensile plasticity over the most rapidly melt-quenched metallic glass with the same composition. Structurally, the β-relaxation is sensitive to the interfacial regions among grains in the nanoglasses. Our results reveal a clear correlation between the amorphous nanostructures and the β-relaxation. It seems that the nanostructuring represents a novel route to obtain high-energy glassy states, that is, the inverse problem of the ultrastable glass.
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Affiliation(s)
- Qun Yang
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, Hubei China
| | - Chao-Qun Pei
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Hai-Bin Yu
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, Hubei China
| | - Tao Feng
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
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19
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Tuning the Johari-Goldstein β-Relaxation and Its Separation from α-Relaxation of Poly(n-alkyl methacrylate)s by Small Molecule-bridged Hydrogen Bonds. CHINESE JOURNAL OF POLYMER SCIENCE 2021. [DOI: 10.1007/s10118-021-2595-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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20
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Zhang H, Wang X, Yu HB, Douglas JF. Dynamic heterogeneity, cooperative motion, and Johari-Goldstein [Formula: see text]-relaxation in a metallic glass-forming material exhibiting a fragile-to-strong transition. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:56. [PMID: 33871722 DOI: 10.1140/epje/s10189-021-00060-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/21/2021] [Indexed: 06/12/2023]
Abstract
We investigate the Johari-Goldstein (JG) [Formula: see text]-relaxation process in a model metallic glass-forming (GF) material ([Formula: see text]), previously studied extensively by both frequency-dependent mechanical measurements and simulation studies devoted to equilibrium properties, by molecular dynamics simulations based on validated and optimized interatomic potentials with the primary aim of better understanding the nature of this universal relaxation process from a dynamic heterogeneity (DH) perspective. The present relatively low temperature and long-time simulations reveal a direct correspondence between the JG [Formula: see text]-relaxation time [Formula: see text] and the lifetime of the mobile particle clusters [Formula: see text], defined as in previous DH studies, a relationship dual to the corresponding previously observed relationship between the [Formula: see text]-relaxation time [Formula: see text] and the lifetime of immobile particle clusters [Formula: see text]. Moreover, we find that the average diffusion coefficient D nearly coincides with [Formula: see text] of the smaller atomic species (Al) and that the 'hopping time' associated with D coincides with [Formula: see text] to within numerical uncertainty, both trends being in accord with experimental studies. This indicates that the JG [Formula: see text]-relaxation is dominated by the smaller atomic species and the observation of a direct relation between this relaxation process and rate of molecular diffusion in GF materials at low temperatures where the JG [Formula: see text]-relaxation becomes the prevalent mode of structural relaxation. As an unanticipated aspect of our study, we find that [Formula: see text] exhibits fragile-to-strong (FS) glass formation, as found in many other metallic GF liquids, but this fact does not greatly alter the geometrical nature of DH in this material and the relation of DH to dynamical properties. On the other hand, the temperature dependence of the DH and dynamical properties, such as the structural relaxation time, can be significantly altered from 'ordinary' GF liquids.
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Affiliation(s)
- Hao Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada.
| | - Xinyi Wang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
| | - Hai-Bin Yu
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Jack F Douglas
- Material Measurement Laboratory, Materials Science and Engineering Division, National Institute of Standards and Technology(NIST), Gaithersburg, MD, 20899, USA.
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21
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Drzewicz A, Jasiurkowska-Delaporte M, Juszyńska-Gałązka E, Zając W, Kula P. On the relaxation dynamics of a double glass-forming antiferroelectric liquid crystal. Phys Chem Chem Phys 2021; 23:8673-8688. [PMID: 33876028 DOI: 10.1039/d0cp06203k] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The relaxation dynamics in the thermodynamic states of the glass-forming antiferroelectric liquid crystal (S)-4'-(1-methyloctyloxycarbonyl) biphenyl-4-yl 4-[7-(2,2,3,3,4,4,4-heptafluorobutoxy) heptyl-1-oxy]-benzoate (3F7HPhH7) was studied by broadband dielectric spectroscopy (BDS). Two glass transitions were found at Tg,1 = 259 K and Tg,2 = 239 K, which were associated with the freezing of anti-phase motions and reorientation around the long molecular axis in the antiferroelectric SmCA* phase, respectively. The low temperature α2-relaxation process shows a Vogel-Fulcher-Tammann (VFT)-type temperature dependence of its structural relaxation time τ(T). The two secondary β- and γ-relaxation modes ascribed to the intramolecular motions observed in the glassy state show Arrhenius behaviour of τ(T). Analysing the band shifts and the oscillator strengths of specific IR absorption bands and their temperature dependencies enables comparing them with the dielectrically determined relaxation dynamics. The kinetics of the isothermal cold crystallization in the temperature range between Tg,1 and Tg,2 was studied in detail using the Avrami and Avrami-Avramow models. This process depends primarily on the diffusion rate and the activation energy is equal to 132 kJ mol-1. The obtained values of the Avrami exponent nA suggest that the crystal growth is three-dimensional.
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Affiliation(s)
- Anna Drzewicz
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland.
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22
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Nowok A, Jurkiewicz K, Dulski M, Hellwig H, Małecki JG, Grzybowska K, Grelska J, Pawlus S. Influence of molecular geometry on the formation, architecture and dynamics of H-bonded supramolecular associates in 1-phenyl alcohols. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115349] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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23
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Diogo HP, Piedade M, Ramos JJM. Structure, thermal properties and molecular mobility in cholesteryl hydrogen phthalate: Different approaches to the crystal, the glassy crystal and the mesophase. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2020.129251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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24
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Gong X, Wang XD, Xu T, Cao Q, Zhang D, Jiang JZ. β-Relaxation and Crystallization Behaviors in a Pulse-Current-Thermoplastic-Formed La-Based Bulk Metallic Glass. J Phys Chem B 2021; 125:657-664. [PMID: 33412855 DOI: 10.1021/acs.jpcb.0c09848] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We use the pulse current thermoplastic forming technique based on joule heating to rejuvenate the atomic structure of a La62Al14Ag2.34Ni10.83Co10.83 bulk metallic glass (BMG). The pulse-formed sample exhibits more pronounced β-relaxation than the as-cast one due to the increased free volume. Instead, the sub-Tg annealing clearly weakens the β-relaxation and also makes it more isolated from the α-relaxation, showing contributions from free volume and preferred structure. However, both treatments exhibit little influence on the following α-relaxation and high temperature crystallization kinetics. Our results open an effective way to rejuvenate the structure of BMGs and provide an in-depth understanding of the relationship between structural relaxations and crystallization kinetics of BMGs.
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Affiliation(s)
- Xingyu Gong
- International Center for New-Structured Materials (ICNSM) and Laboratory of New-Structured Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Xiao-Dong Wang
- International Center for New-Structured Materials (ICNSM) and Laboratory of New-Structured Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Tianding Xu
- International Center for New-Structured Materials (ICNSM) and Laboratory of New-Structured Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Qingping Cao
- International Center for New-Structured Materials (ICNSM) and Laboratory of New-Structured Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Dongxian Zhang
- State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Jian-Zhong Jiang
- International Center for New-Structured Materials (ICNSM) and Laboratory of New-Structured Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
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25
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Heczko D, Jurkiewicz K, Tarnacka M, Grelska J, Wrzalik R, Kamiński K, Paluch M, Kamińska E. The impact of chemical structure on the formation of the medium-range order and dynamical properties of selected antifungal APIs. Phys Chem Chem Phys 2020; 22:28202-28212. [PMID: 33295350 DOI: 10.1039/d0cp02332a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper, we have analyzed structural, thermal, and dynamical properties of four azole antifungals: itraconazole (ITZ), posaconazole (POS), terconazole (TER) and ketoconazole (KET), differing mainly in the length of the rod-like backbone and slightly in side groups. Our investigations clearly demonstrated that the changes in the chemical structure result in a different ability to form the medium-range order (MRO) and variation in thermal and dynamical properties of these pharmaceuticals. Direct comparison of the diffractograms collected for glassy and crystalline materials indicated that the MRO observed in the former phases is related to maintaining the local molecular arrangement of the crystal structure. Moreover, it was shown that once the MRO-related diffraction peaks appear, additional mobility (δ- or α' relaxation), slower than the structural (α)-process, is also detected in dielectric spectra. This new mode is connected to the motions within supramolecular nanoaggregates. Detailed analysis of dielectric and calorimetric data also revealed that the variation in the internal structure and MRO of the examined pharmaceuticals have an impact on the glass transition temperature (Tg) shape of the α-process, isobaric fragility, molecular dynamics in the glassy state and number of dynamically correlated molecules. These findings could be helpful in an understanding the influence of different types of intermolecular MRO on the properties of substances having a similar chemical backbone.
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Affiliation(s)
- Dawid Heczko
- Department of Pharmacognosy and Phytochemistry, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia in Katowice, ul. Jagiellońska 4, 41-200 Sosnowiec, Poland.
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26
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Shi G, Liu Y, Wu G. βfast Relaxation Governs the Damping Stability of Acrylic Polymer/Hindered Phenol Hybrids. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00255] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gaopeng Shi
- Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science & Technology, Shanghai 200237, China
| | - Yuanbiao Liu
- Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science & Technology, Shanghai 200237, China
| | - Guozhang Wu
- Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science & Technology, Shanghai 200237, China
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27
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Hellwig H, Nowok A, Małecki JG, Kuś P, Jędrzejowska A, Grzybowska K, Pawlus S. Conformational analysis and molecular dynamics of glass-forming aromatic thiacrown ethers. Phys Chem Chem Phys 2020; 22:17948-17959. [DOI: 10.1039/d0cp02585b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dielectric properties, glass transition temperature and molecular dynamics of thiacrown ethers are strongly dependent on the thiacrown ring type.
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Affiliation(s)
- Hubert Hellwig
- Institute of Chemistry
- University of Silesia
- 40-006 Katowice
- Poland
| | - Andrzej Nowok
- August Chełkowski Institute of Physics
- University of Silesia
- 41-500 Chorzów
- Poland
| | | | - Piotr Kuś
- Institute of Chemistry
- University of Silesia
- 40-006 Katowice
- Poland
| | | | | | - Sebastian Pawlus
- August Chełkowski Institute of Physics
- University of Silesia
- 41-500 Chorzów
- Poland
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28
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Romanini M, Rodriguez S, Valenti S, Barrio M, Tamarit JL, Macovez R. Nose Temperature and Anticorrelation between Recrystallization Kinetics and Molecular Relaxation Dynamics in Amorphous Morniflumate at High Pressure. Mol Pharm 2019; 16:3514-3523. [DOI: 10.1021/acs.molpharmaceut.9b00351] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Michela Romanini
- Grup de Caracterització de Materials, Departament de Física and Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya, EEBE, Campus Diagonal-Besòs, Av. Eduard Maristany 10-14, E-08019 Barcelona, Catalonia, Spain
| | - Sergio Rodriguez
- Grup de Caracterització de Materials, Departament de Física and Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya, EEBE, Campus Diagonal-Besòs, Av. Eduard Maristany 10-14, E-08019 Barcelona, Catalonia, Spain
| | - Sofia Valenti
- Grup de Caracterització de Materials, Departament de Física and Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya, EEBE, Campus Diagonal-Besòs, Av. Eduard Maristany 10-14, E-08019 Barcelona, Catalonia, Spain
| | - María Barrio
- Grup de Caracterització de Materials, Departament de Física and Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya, EEBE, Campus Diagonal-Besòs, Av. Eduard Maristany 10-14, E-08019 Barcelona, Catalonia, Spain
| | - Josep Lluis Tamarit
- Grup de Caracterització de Materials, Departament de Física and Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya, EEBE, Campus Diagonal-Besòs, Av. Eduard Maristany 10-14, E-08019 Barcelona, Catalonia, Spain
| | - Roberto Macovez
- Grup de Caracterització de Materials, Departament de Física and Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya, EEBE, Campus Diagonal-Besòs, Av. Eduard Maristany 10-14, E-08019 Barcelona, Catalonia, Spain
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29
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Zheng Q, Zhang Y, Montazerian M, Gulbiten O, Mauro JC, Zanotto ED, Yue Y. Understanding Glass through Differential Scanning Calorimetry. Chem Rev 2019; 119:7848-7939. [DOI: 10.1021/acs.chemrev.8b00510] [Citation(s) in RCA: 154] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Qiuju Zheng
- School of Materials Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
| | - Yanfei Zhang
- School of Materials Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
| | - Maziar Montazerian
- Vitreous Materials Laboratory (LaMaV), Department of Materials Engineering (DEMa), Federal University of São Carlos (UFSCar), 13.565-905 São Carlos, SP, Brazil
| | - Ozgur Gulbiten
- Science and Technology Division, Corning Incorporated, Corning, New York 14831, United States
| | - John C. Mauro
- School of Materials Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Edgar D. Zanotto
- Vitreous Materials Laboratory (LaMaV), Department of Materials Engineering (DEMa), Federal University of São Carlos (UFSCar), 13.565-905 São Carlos, SP, Brazil
| | - Yuanzheng Yue
- School of Materials Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, China
- Department of Chemistry and Bioscience, Aalborg University, DK-9220 Aalborg, Denmark
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30
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Atawa B, Correia NT, Couvrat N, Affouard F, Coquerel G, Dargent E, Saiter A. Molecular mobility of amorphous N-acetyl-α-methylbenzylamine and Debye relaxation evidenced by dielectric relaxation spectroscopy and molecular dynamics simulations. Phys Chem Chem Phys 2019; 21:702-717. [DOI: 10.1039/c8cp04880k] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Molecular mobility of NAC-MBA molecule is described by means of DRS, FSC and MD simulations.
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31
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Correlation between molecular dynamics and physical stability of two milled anhydrous sugars: Lactose and sucrose. Int J Pharm 2018; 551:184-194. [PMID: 30223078 DOI: 10.1016/j.ijpharm.2018.09.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 09/12/2018] [Accepted: 09/12/2018] [Indexed: 11/24/2022]
Abstract
The process of milling often results in amorphization and the physical stability of amorphous phase is linked with its molecular dynamics. This study focuses on a propensity of two disaccharides (lactose and sucrose) to amorphize on ball milling and the stability of the resultant amorphous phase. The amorphous content in milled sugars is estimated by Differential Scanning Calorimetry (DSC) and the stability was measured in terms of the tendency to recrystallize by Broadband Dielectric Spectroscopy (BDS). The results show that the amorphous content increases with milling time and is greater for lactose than sucrose. At the same degree of amorphization, sucrose recrystallize at temperature ∼15 °C higher than lactose, indicating higher stability. The molecular dynamics (beta relaxation process), suggest that milled sucrose is more stable with higher activation energy (∼9 kJ mol-1) than that of lactose. The moisture content of amorphous phase also impacts its molecular dynamics in terms of increase in activation energy as the moisture decrease with increasing the milling times. The study suggests a greater stability of amorphous sucrose and susceptibility of milled lactose to recrystallize, however, on extended milling when the moisture content decreases, lactose was seen to become relatively more stable.
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32
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Moura Ramos JJ, Piedade MFM, Diogo HP, Viciosa MT. Thermal Behavior and Slow Relaxation Dynamics in Amorphous Efavirenz: A Study by DSC, XRPD, TSDC, and DRS. J Pharm Sci 2018; 108:1254-1263. [PMID: 30391416 DOI: 10.1016/j.xphs.2018.10.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 10/12/2018] [Accepted: 10/24/2018] [Indexed: 10/27/2022]
Abstract
The analysis of the thermal behavior of efavirenz showed a high glass-forming ability and good glass stability of this glass-forming liquid at room temperature. No polymorphic forms were formed either by cold crystallization or by recrystallization from solvent acetone. The determination of the dynamic fragility by the differential scanning calorimetry, thermally stimulated depolarization currents (TSDC), and dielectric relaxation spectroscopy (DRS) techniques is unanimous in suggesting efavirenz as a moderately fragile liquid. With DRS, secondary relaxations were detected, however, with weak intensities that did not allow the respective kinetic analysis; in contrast, TSDC allows clearly resolving the components of the secondary β-relaxation below Tg, with activation energies distributed between about 75 and 90 kJ mol-1 and Arrhenius prefactors of the order of 10-13 s. In this regard, the TSDC technique proved to be more effective compared to DRS in characterizing the secondary relaxation. The glass forming ability and glass stability found for efavirenz have been discussed in terms of various thermodynamic and kinetic parameters such as the reduced glass transition temperature, Tgred, the dynamic fragility, m, the stretching exponent, βKWW, the melting entropy, ΔSfus, and the molecular stiffness. The exceptionally low value of efavirenz fusion entropy was highlighted as a key feature of the thermal behavior of this glass-forming liquid.
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Affiliation(s)
- Joaquim J Moura Ramos
- CQE- Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal; CQFM - Centro de Química-Física Molecular and IN - Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - M Fátima M Piedade
- CQFM - Centro de Química-Física Molecular and IN - Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal; CQB - Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1649-016 Lisboa, Portugal
| | - Hermínio P Diogo
- CQFM - Centro de Química-Física Molecular and IN - Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.
| | - M Teresa Viciosa
- CQE- Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal; CQFM - Centro de Química-Física Molecular and IN - Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.
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33
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Heczko D, Kamińska E, Minecka A, Tarnacka M, Waliłko P, Kasprzycka A, Kamiński K, Paluch M. Studies on the molecular dynamics of acetylated oligosaccharides of different topologies (linear versus cyclic). Carbohydr Polym 2018; 206:273-280. [PMID: 30553322 DOI: 10.1016/j.carbpol.2018.10.118] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/12/2018] [Accepted: 10/31/2018] [Indexed: 10/27/2022]
Abstract
In this paper, the molecular dynamics and thermal properties of representative acetylated linear and cyclic oligosaccharides: acTRE, acRAF, acSTA, ac-α-CD, ac-β-CD, ac-γ-CD, have been investigated by using broadband dielectric spectroscopy and differential scanning calorimetry. We found that there are marked differences in the dynamics of the structural and secondary relaxation processes in both groups of materials. Just to mention a variation in the distribution of the structural relaxation times as well as different evolutions of the glass transition temperature (Tg) and fragility (m) versus molecular weight (Mw), which seem to be affected by the shape of the molecule, strain in the carbohydrate ring and mobility of side acetyl moieties.
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Affiliation(s)
- Dawid Heczko
- Department of Pharmacognosy and Phytochemistry, Medical University of Silesia in Katowice, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, ul. Jagiellonska 4, 41-200 Sosnowiec, Poland.
| | - Ewa Kamińska
- Department of Pharmacognosy and Phytochemistry, Medical University of Silesia in Katowice, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, ul. Jagiellonska 4, 41-200 Sosnowiec, Poland.
| | - Aldona Minecka
- Department of Pharmacognosy and Phytochemistry, Medical University of Silesia in Katowice, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, ul. Jagiellonska 4, 41-200 Sosnowiec, Poland
| | - Magdalena Tarnacka
- Silesian Center for Education and Interdisciplinary Research, University of Silesia, ul. 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland; Institute of Physics, University of Silesia, ul. 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
| | - Patrycja Waliłko
- Silesian Technical University of Technology, Department of Chemistry, ul. Krzywoustego 4, 44-100 Gliwice, Poland; Biotechnology Centre, Silesian Technical University of Technology, ul. Krzywoustego 8, 44-100 Gliwice, Poland
| | - Anna Kasprzycka
- Silesian Technical University of Technology, Department of Chemistry, ul. Krzywoustego 4, 44-100 Gliwice, Poland; Biotechnology Centre, Silesian Technical University of Technology, ul. Krzywoustego 8, 44-100 Gliwice, Poland
| | - Kamil Kamiński
- Silesian Center for Education and Interdisciplinary Research, University of Silesia, ul. 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland; Institute of Physics, University of Silesia, ul. 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
| | - Marian Paluch
- Silesian Center for Education and Interdisciplinary Research, University of Silesia, ul. 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland; Institute of Physics, University of Silesia, ul. 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
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34
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Asandulesa M, Musteata VE, Bele A, Dascalu M, Bronnikov S, Racles C. Molecular dynamics of polysiloxane polar-nonpolar co-networks and blends studied by dielectric relaxation spectroscopy. POLYMER 2018. [DOI: 10.1016/j.polymer.2018.06.061] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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35
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Minecka A, Kaminska E, Heczko D, Tarnacka M, Grudzka-Flak I, Bartoszek M, Zięba A, Wrzalik R, Śmiszek-Lindert WE, Dulski M, Kaminski K, Paluch M. Studying molecular dynamics of the slow, structural, and secondary relaxation processes in series of substituted ibuprofens. J Chem Phys 2018; 148:224505. [PMID: 29907061 DOI: 10.1063/1.5026818] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this paper, the molecular dynamics of a series of ester derivatives of ibuprofen (IBU), in which the hydrogen atom from the hydroxyl group was substituted by the methyl, isopropyl, hexyl, and benzyl moieties, has been investigated using Broadband dielectric (BD), Nuclear magnetic resonance (NMR), and Raman spectroscopies. We found that except for benzyl IBU (Ben-IBU), an additional process (slow mode, SM) appears in dielectric spectra in all examined compounds. It is worth noting that this relaxation process was observed for the first time in non-modified IBU (a Debye relaxation). According to suggestions by Affouard and Correia [J. Phys. Chem. B. 114, 11397 (2010)] as well as further studies by Adrjanowicz et al. [J. Chem. Phys. 139, 111103 (2013)] on Met-IBU, it was attributed to synperiplanar-antiperiplanar conformational changes within the molecule. Herein, we have shown that with an increasing molecular weight of the substituent, the relaxation times of the SM become longer and its activation energy significantly increases. Moreover, this new relaxation mode was found to be broader than a simple Debye relaxation in Iso-IBU and Hex-IBU. Additional complementary NMR studies indicated that either there is a significant slowdown of the rotation around the O=C-O-R moiety or this kind of movement is completely suppressed in the case of Ben-IBU. Therefore, the SM is not observed in the dielectric loss spectra of this compound. Finally, we carried out isothermal experiments on the samples which have a different thermal history. Interestingly, it turned out that the relaxation times of the structural processes are slightly shorter with respect to those obtained from temperature dependent measurements. This effect was the most prominent in the case of Hex-IBU, while for Ben-IBU, it was not observed at all. Additional time-dependent measurements revealed the ongoing equilibration manifested by the continuous shift of the structural process, until it finally reached its equilibrium position. Further Raman investigations showed that this effect may be related to the rotational/conformational equilibration of the long hexyl chains. Our results are the first ones demonstrating that the structural process is sensitive to the conformational equilibration occurring in the specific highly viscous systems.
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Affiliation(s)
- A Minecka
- Department of Pharmacognosy and Phytochemistry, Medical University of Silesia in Katowice, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Jagiellonska 4, 41-200 Sosnowiec, Poland
| | - E Kaminska
- Department of Pharmacognosy and Phytochemistry, Medical University of Silesia in Katowice, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Jagiellonska 4, 41-200 Sosnowiec, Poland
| | - D Heczko
- Department of Pharmacognosy and Phytochemistry, Medical University of Silesia in Katowice, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Jagiellonska 4, 41-200 Sosnowiec, Poland
| | - M Tarnacka
- Institute of Physics, University of Silesia, ul. 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
| | - I Grudzka-Flak
- Institute of Physics, University of Silesia, ul. 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
| | - M Bartoszek
- Institute of Chemistry, University of Silesia, Szkolna 9, 40-007 Katowice, Poland
| | - A Zięba
- Department of Organic Chemistry, Medical University of Silesia in Katowice, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Jagiellonska 4, 41-200 Sosnowiec, Poland
| | - R Wrzalik
- Institute of Physics, University of Silesia, ul. 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
| | - W E Śmiszek-Lindert
- Department of Pharmacognosy and Phytochemistry, Medical University of Silesia in Katowice, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Jagiellonska 4, 41-200 Sosnowiec, Poland
| | - M Dulski
- Silesian Center for Education and Interdisciplinary Research, University of Silesia, ul. 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland
| | - K Kaminski
- Institute of Physics, University of Silesia, ul. 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
| | - M Paluch
- Institute of Physics, University of Silesia, ul. 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
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36
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Ransom TC, Fragiadakis D, Roland CM. The α and Johari–Goldstein Relaxations in 1,4-Polybutadiene: Breakdown of Isochronal Superpositioning. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00664] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- T. C. Ransom
- Chemistry Division, Naval Research Laboratory, Code 6105, Washington, D.C. 20375-5342, United States
| | - D. Fragiadakis
- Chemistry Division, Naval Research Laboratory, Code 6105, Washington, D.C. 20375-5342, United States
| | - C. M. Roland
- Chemistry Division, Naval Research Laboratory, Code 6105, Washington, D.C. 20375-5342, United States
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37
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Harris MA, Heres MF, Coote J, Wenda A, Strehmel V, Stein GE, Sangoro J. Ion Transport and Interfacial Dynamics in Disordered Block Copolymers of Ammonium-Based Polymerized Ionic Liquids. Macromolecules 2018. [DOI: 10.1021/acs.macromol.7b02729] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Matthew A. Harris
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Maximilian F. Heres
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Jonathan Coote
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - André Wenda
- Department of Chemistry, Institute for Coatings and Surface Chemistry, Niederrhein University of Applied Sciences, D-47798 Krefeld, Germany
| | - Veronika Strehmel
- Department of Chemistry, Institute for Coatings and Surface Chemistry, Niederrhein University of Applied Sciences, D-47798 Krefeld, Germany
| | - Gila E. Stein
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Joshua Sangoro
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
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38
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Aji DPB, Johari GP. Decrease in electrical resistivity on depletion of islands of mobility during aging of a bulk metal glass. J Chem Phys 2018; 148:144506. [PMID: 29655350 DOI: 10.1063/1.5024999] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The effect of structural relaxation on electrical resistivity, ρglass, of strain-free Zr46.75Ti8.25Cu7.5Ni10Be27.5 bulk metallic glass was studied during isothermal aging at several temperatures, Tas. Since cooling of a liquid metal increases its resistivity ρliq, one expects ρglass to increase on aging toward ρliq at T = Ta. Instead, ρglass decreased non-exponentially with the aging time. The activation energy of aging kinetics is 189 kJ mol-1, which is higher than the activation energy of the Johari-Goldstein (JG) relaxation. After considering the sample's contraction, phase separation, and crystallization as possible causes of the decrease in ρglass, we attribute the decrease to depletion of islands of atomic mobility, soft spots, or static heterogeneity. Vibrations of the atoms in these local (loosely packed) regions and in the region's interfacial area contribute to electron scattering. As these deplete on aging, the contribution decreases and ρglass decreases, with a concomitant decrease in macroscopic volume, enthalpy, and entropy (V, H, and S). Local regions of faster mobility also decrease on cooling as V, H, and S of a liquid decrease, but structure fluctuations dominate electron scattering of a liquid metal and ρliq increases effectively according to the Ziman-Nagel theory for a homogenously disordered structure. Whether depletion of such local regions initiates the structural relaxation of a glass, or vice versa, may be resolved by finding a glass that physically ages but shows no JG relaxation.
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Affiliation(s)
- Daisman P B Aji
- Department of Mechanical Engineering, Trisakti University, Jakarta 11440, Indonesia
| | - G P Johari
- Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7, Canada
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39
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Urakawa O, Yamane M, Tomie S, Inoue T, Shikata T, Adachi K. Relationship between global and segmental dynamics of poly(butylene oxide) studied by broadband dielectric spectroscopy. J Chem Phys 2018; 148:034904. [DOI: 10.1063/1.5006364] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Osamu Urakawa
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Minoru Yamane
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Shota Tomie
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Tadashi Inoue
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Toshiyuki Shikata
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Keiichiro Adachi
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
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40
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Minecka A, Kamińska E, Tarnacka M, Dzienia A, Madejczyk O, Waliłko P, Kasprzycka A, Kamiński K, Paluch M. High pressure studies on structural and secondary relaxation dynamics in silyl derivative of D-glucose. J Chem Phys 2017; 147:064502. [DOI: 10.1063/1.4989679] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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41
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Chen Y, Mao J, Zhu Y, Zhang K, Wu G, Wu J, Zhang H. Structure and properties of microwave transparent crosslinked polystyrene prepared through 3D printing bulk polymerization. J Appl Polym Sci 2017. [DOI: 10.1002/app.44865] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yuanwu Chen
- School of Material and Energy; Guangdong University of Technology; Guangdong China
- Department of Mechanical and Aerospace Engineering; the Hong Kong University of Science and Technology; Clear Water Bay Kowloon Hong Kong
| | - Jiale Mao
- Department of Mechanical and Aerospace Engineering; the Hong Kong University of Science and Technology; Clear Water Bay Kowloon Hong Kong
- State Key laboratory of Electrical Insulation and Power Equipment; Xi'an Jiaotong University; Xi'an China
| | - Yejun Zhu
- Department of Mechanical and Aerospace Engineering; the Hong Kong University of Science and Technology; Clear Water Bay Kowloon Hong Kong
| | - Kai Zhang
- Department of Mechanical and Aerospace Engineering; the Hong Kong University of Science and Technology; Clear Water Bay Kowloon Hong Kong
| | - Gangpeng Wu
- Department of Mechanical and Aerospace Engineering; the Hong Kong University of Science and Technology; Clear Water Bay Kowloon Hong Kong
| | - Jingshen Wu
- Department of Mechanical and Aerospace Engineering; the Hong Kong University of Science and Technology; Clear Water Bay Kowloon Hong Kong
| | - Haiyan Zhang
- School of Material and Energy; Guangdong University of Technology; Guangdong China
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42
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Zajac M, Kahl H, Schade B, Rödel T, Dionisio M, Beiner M. Relaxation behavior of polyurethane networks with different composition and crosslinking density. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.01.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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43
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Castelvetro V, Capaccioli S, Raihane M, Atlas S. Complex Dynamics of a Fluorinated Vinylidene Cyanide Copolymer Highlighted by Dielectric Relaxation Spectroscopy. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00683] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Valter Castelvetro
- Dipartimento
di Chimica e Chimica Industriale, Università di Pisa, via G. Moruzzi
13, I-56124, Pisa, Italy
| | - Simone Capaccioli
- Dipartimento
di Fisica, Università di Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy
| | - Mustapha Raihane
- Laboratory
of Organometallic and Macromolecular Chemistry-Composite Materials,
Faculty of Sciences and Techniques, Cadi Ayyad University, Avenue
Abdelkrim Khattabi, BP 549, 40000 Marrakech, Morocco
| | - Salima Atlas
- Laboratory
of Organometallic and Macromolecular Chemistry-Composite Materials,
Faculty of Sciences and Techniques, Cadi Ayyad University, Avenue
Abdelkrim Khattabi, BP 549, 40000 Marrakech, Morocco
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44
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Zhao LZ, Xue RJ, Zhu ZG, Ngai KL, Wang WH, Bai HY. A fast dynamic mode in rare earth based glasses. J Chem Phys 2016; 144:204507. [DOI: 10.1063/1.4952421] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- L. Z. Zhao
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - R. J. Xue
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Z. G. Zhu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - K. L. Ngai
- Dipartimento di Fisica, Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa, Italy
| | - W. H. Wang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - H. Y. Bai
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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45
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Intrinsic correlation between β-relaxation and spatial heterogeneity in a metallic glass. Nat Commun 2016; 7:11516. [PMID: 27158084 PMCID: PMC4865810 DOI: 10.1038/ncomms11516] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 04/05/2016] [Indexed: 12/03/2022] Open
Abstract
β-relaxation has long been attributed to localized motion of constituent molecules or atoms confined to isolated regions in glasses. However, direct experimental evidence to support this spatially heterogeneous scenario is still missing. Here we report the evolution of nanoscale structural heterogeneity in a metallic glass during β-relaxation by utilizing amplitude-modulation dynamic atomic force microscopy. The successive degeneration of heterogeneity during β-relaxation can be well described by the Kohlrausch–Williams–Watts equation. The characteristic relaxation time and activation energy of the heterogeneity evolution are in accord with those of excess enthalpy release by β-relaxation. Our study correlates β-relaxation with nanoscale spatial heterogeneity and provides direct evidence on the structural origins of β-relaxation in metallic glasses. Beta-relaxation in glasses is commonly attributed to the confined motions of constituent atoms in nanosized domains, but there is no direct evidence so far. Here, Zhu et al. show the correlation between the evolution of spatial heterogeneity at nanoscale and beta-relaxation below glass transition point.
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46
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Grzybowska K, Capaccioli S, Paluch M. Recent developments in the experimental investigations of relaxations in pharmaceuticals by dielectric techniques at ambient and elevated pressure. Adv Drug Deliv Rev 2016; 100:158-82. [PMID: 26705851 DOI: 10.1016/j.addr.2015.12.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 12/05/2015] [Accepted: 12/09/2015] [Indexed: 10/22/2022]
Abstract
In recent years, there is a growing interest in improving the physicochemical stability of amorphous pharmaceutical solids due to their very promising applications to manufacture medicines characterized by a better water solubility, and consequently by a higher dissolution rate than those of their crystalline counterparts. In this review article, we show that the molecular mobility investigated both in the supercooled liquid and glassy states is the crucial factor required to understand molecular mechanisms that govern the physical stability of amorphous drugs. We demonstrate that pharmaceuticals can be thoroughly examined by means of the broadband dielectric spectroscopy, which is a very useful experimental technique to explore different relaxation processes and crystallization kinetics as well. Such studies conducted in the wide temperature and pressure ranges provide data needed in searching correlations between properties of molecular dynamics and crystallization process, which are aimed at developing effective and efficient methods for stabilizing amorphous drugs.
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47
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The slow relaxation dynamics in active pharmaceutical ingredients studied by DSC and TSDC: Voriconazole, miconazole and itraconazole. Int J Pharm 2016; 501:39-48. [DOI: 10.1016/j.ijpharm.2016.01.057] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Revised: 01/21/2016] [Accepted: 01/22/2016] [Indexed: 11/19/2022]
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48
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Sun Q, Hu L, Zhou C, Zheng H, Yue Y. Correlation between supercooled liquid relaxation and glass Poisson’s ratio. J Chem Phys 2015; 143:164504. [DOI: 10.1063/1.4934228] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Qijing Sun
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China
| | - Lina Hu
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China
| | - Chao Zhou
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China
| | - Haijiao Zheng
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China
| | - Yuanzheng Yue
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China
- Section of Chemistry, Aalborg University, DK-9000 Aalborg, Denmark
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49
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Pérez SC, Zuriaga M, Serra P, Wolfenson A, Negrier P, Tamarit JL. Dynamic characterization of crystalline and glass phases of deuterated 1,1,2,2 tetrachloroethane. J Chem Phys 2015; 143:134502. [DOI: 10.1063/1.4931824] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Silvina C. Pérez
- Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba and IFEG-CONICET, Ciudad Universitaria, X5016LAE Córdoba, Argentina
| | - Mariano Zuriaga
- Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba and IFEG-CONICET, Ciudad Universitaria, X5016LAE Córdoba, Argentina
| | - Pablo Serra
- Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba and IFEG-CONICET, Ciudad Universitaria, X5016LAE Córdoba, Argentina
| | - Alberto Wolfenson
- Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba and IFEG-CONICET, Ciudad Universitaria, X5016LAE Córdoba, Argentina
| | - Philippe Negrier
- Université Bordeaux, LOMA, UMR 5798, F-33400 Talence, France and LOMA, UMR 5798, F-33400 Talence, France
| | - Josep Lluis Tamarit
- Grup de Caracterització de Materials, Departament de Física i Enginyeria Nuclear, ETSEIB, Diagonal 647, Universitat Politècnica de Catalunya, 08028 Barcelona, Catalonia, Spain
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50
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Redondo-Foj B, Sanchis MJ, Ortiz-Serna P, Carsí M, García JM, García FC. The effect of cross-linking on the molecular dynamics of the segmental and β Johari-Goldstein processes in polyvinylpyrrolidone-based copolymers. SOFT MATTER 2015; 11:7171-7180. [PMID: 26255757 DOI: 10.1039/c5sm00714c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The effect of the cross-link density on the molecular dynamics of copolymers composed of vinylpyrrolidone (VP) and butyl acrylate (BA) was studied using differential scanning calorimetry (DSC) and dielectric relaxation spectroscopy (DRS). A single glass transition was detected by DSC measurements. The dielectric spectra exhibit conductive processes and three dipolar relaxations labeled as α, β and γ in the decreasing order of temperatures. The cross-linker content affects both α and β processes, but the fastest γ process is relatively unaffected. An increase of cross-linking produces a typical effect on the α process dynamics: (i) the glass transition temperature is increased, (ii) the dispersion is broadened, (iii) its strength is decreased and (iv) the relaxation times are increased. However, the β process, which possesses typical features of a pure Johari-Goldstein relaxation, unexpectedly loses the intermolecular character for the highest cross-linker content.
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Affiliation(s)
- Belén Redondo-Foj
- Instituto Tecnología Eléctrica, Departamento de Termodinámica Aplicada, Universitat Politècnica de València, Camí de Vera s/n, 46022, Valencia, Spain.
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