1
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Beena Unni A, Winkler R, Duarte DM, Chat K, Adrjanowicz K. Influence of Surface Roughness on the Dynamics and Crystallization of Vapor-Deposited Thin Films. J Phys Chem B 2022; 126:8072-8079. [PMID: 36170644 PMCID: PMC9574919 DOI: 10.1021/acs.jpcb.2c04541] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
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The substrate roughness
is a very important parameter that can
influence the properties of supported thin films. In this work, we
investigate the effect of surface roughness on the properties of a
vapor-deposited glass (celecoxib, CXB) both in its bulk and in confined
states. Using dielectric spectroscopy, we provide experimental evidence
depicting a profound influence of surface roughness on the α-relaxation
dynamics and the isothermal crystallization of this vapor-deposited
glass. Besides, we have verified the influence of film confinement
on varying values of surface roughnesses as well. At a fixed surface
roughness value, the confinement could alter both the dynamics and
crystallization of vapor-deposited CXB.
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Affiliation(s)
- Aparna Beena Unni
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland.,Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Roksana Winkler
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland.,Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Daniel Marques Duarte
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland.,Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Katarzyna Chat
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland.,Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Karolina Adrjanowicz
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland.,Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
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2
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Unni AB, Winkler R, Duarte DM, Tu W, Chat K, Adrjanowicz K. Vapor-Deposited Thin Films: Studying Crystallization and α-relaxation Dynamics of the Molecular Drug Celecoxib. J Phys Chem B 2022; 126:3789-3798. [PMID: 35580265 PMCID: PMC9150116 DOI: 10.1021/acs.jpcb.2c01284] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Crystallization is one of the major challenges in using glassy solids for technological applications. Considering pharmaceutical drugs, maintaining a stable amorphous form is highly desirable for improved solubility. Glasses prepared by the physical vapor deposition technique got attention because they possess very high stability, taking thousands of years for an ordinary glass to achieve. In this work, we have investigated the effect of reducing film thickness on the α-relaxation dynamics and crystallization tendency of vapor-deposited films of celecoxib (CXB), a pharmaceutical substance. We have scrutinized its crystallization behavior above and below the glass-transition temperature (Tg). Even though vapor deposition of CXB cannot inhibit crystallization completely, we found a significant decrease in the crystallization rate with decreasing film thickness. Finally, we have observed striking differences in relaxation dynamics of vapor-deposited thin films above the Tg compared to spin-coated counterparts of the same thickness.
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Affiliation(s)
- Aparna Beena Unni
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland.,Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Roksana Winkler
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland.,Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Daniel Marques Duarte
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland.,Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Wenkang Tu
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland.,Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Katarzyna Chat
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland.,Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Karolina Adrjanowicz
- Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland.,Silesian Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
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3
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Probing Small-Angle Molecular Motions with EPR Spectroscopy: Dynamical Transition and Molecular Packing in Disordered Solids. MAGNETOCHEMISTRY 2022. [DOI: 10.3390/magnetochemistry8020019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Disordered molecular solids present a rather broad class of substances of different origin—amorphous polymers, materials for photonics and optoelectronics, amorphous pharmaceutics, simple molecular glass formers, and others. Frozen biological media in many respects also may be referred to this class. Theoretical description of dynamics and structure of disordered solids still does not exist, and only some phenomenological models can be developed to explain results of particular experiments. Among different experimental approaches, electron paramagnetic resonance (EPR) applied to spin probes and labels also can deliver useful information. EPR allows probing small-angle orientational molecular motions (molecular librations), which intrinsically are inherent to all molecular solids. EPR is employed in its conventional continuous wave (CW) and pulsed—electron spin echo (ESE)—versions. CW EPR spectra are sensitive to dynamical librations of molecules while ESE probes stochastic molecular librations. In this review, different manifestations of small-angle motions in EPR of spin probes and labels are discussed. It is shown that CW-EPR-detected dynamical librations provide information on dynamical transition in these media, similar to that explored with neutron scattering, and ESE-detected stochastic librations allow elucidating some features of nanoscale molecular packing. The possible EPR applications are analyzed for gel-phase lipid bilayers, for biological membranes interacting with proteins, peptides and cryoprotectants, for supercooled ionic liquids (ILs) and supercooled deep eutectic solvents (DESs), for globular proteins and intrinsically disordered proteins (IDPs), and for some other molecular solids.
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4
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A Combined Atomic and Molecular Probe Characterization of Aromatic Hydrocarbons via PALS and ESR: Methylbenzene. MATERIALS 2022; 15:ma15020462. [PMID: 35057182 PMCID: PMC8777640 DOI: 10.3390/ma15020462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/27/2021] [Accepted: 01/05/2022] [Indexed: 01/27/2023]
Abstract
A combined study of one of the simplest aromatic hydrocarbons, i.e., methylbenzene (toluene) (TOL), via the annihilation of an ortho-positronium (o-Ps) probe via positron annihilation lifetime spectroscopy (PALS) and the rotation dynamics of nitroxide spin probe 2,2,6,6-tetramethyl-piperidinyl-1-oxy (TEMPO) using electron spin resonance (ESR) over a wide temperature range, 10–300 K, is reported. The o-Ps lifetime, τ3, and the relative o-Ps intensity, I3, as a function of temperature exhibit changes defining several characteristic PALS temperatures in the slowly and rapidly cooled samples. Similarly, the spectral parameter of TEMPO mobility in TOL, 2Azz‘, and its correlation time, τc, reveal several effects at a set of the characteristic ESR temperatures, which were determined and compared with the PALS results. Finally, the physical origins of the changes in free volume expansion and spin probe mobility are revealed. They are reflected in a series of the mutual coincidences between the characteristic PALS and ESR temperatures and appropriate complementary thermodynamic and dynamic techniques.
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5
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Cassidy A, Jørgensen MRV, Glavic A, Lauter V, Plekan O, Field D. Low temperature aging in a molecular glass: the case of cis-methyl formate. Phys Chem Chem Phys 2021; 23:15719-15726. [PMID: 34279530 DOI: 10.1039/d1cp01332g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Glassy films of cis-methyl formate show spontaneous dipole orientation on deposition from the vacuum, the so-called 'spontelectric effect', creating surface potentials and electric fields within the films. We follow the decay of these fields, and their accompanying dipole orientation, on the hours timescale at deposition temperatures between 40 K and 55 K. Our data trace the low temperature 'secondary decay' mechanism, at tens of degrees below the glass transition temperature of 90 K. We show that secondary decay is due to molecular rotation, with associated activation energies lying between 0.1 and 0.2 eV. Diffusion is absent, as established from published neutron reflectivity data. Using an analytical model for the spontelectric effect, data are placed on a quantitative footing, showing that angular motion in excess of 50° reproduces the observed values of activation energies. Exploitation of the spontelectric effect is new in the study of glass aging and is shown here to give insight into the elusive processes which take place far from the molecular glass transition temperature.
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Affiliation(s)
- Andrew Cassidy
- Center for Interstellar Catalysis and Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus C, Denmark.
| | - Mads R V Jørgensen
- Center of Materials Crystallography, iNano & Department of Chemistry, Aarhus University, Langelandsgade 140, Aarhus C, Denmark and MAX IV Laboratory, Lund University, Fotongatan 2, Lund, Sweden
| | - Artur Glavic
- Laboratory for Neutron and Muon Instrumentation, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Valeria Lauter
- Neutron Scattering Division, Oak Ridge National Lab, Oak Ridge, TN 37831, USA
| | - Oksana Plekan
- Sincrotrone Trieste S.C.P.A., Area Science Park, Strada Statale 14, km 163.5, I-34149 Basovizza, Trieste, Italy
| | - David Field
- Center for Interstellar Catalysis and Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus C, Denmark.
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6
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Zuhaib A, Urquhart SG. Internal molecular conformation of organic glasses: A NEXAFS study. J Chem Phys 2021; 155:034503. [PMID: 34293907 DOI: 10.1063/5.0054442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The origin of the exceptional stability of molecular glasses grown by physical vapor deposition (PVD) is not well understood. Differences in glass density have been correlated with thermodynamic stability for thin films of N,N'-Bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD) grown by PVD at specific substrate temperatures below the glass transition temperature. However, the relationship between the internal conformation of glass molecules and the thermodynamic properties of molecular glasses is not well studied. We use carbon 1s near edge x-ray absorption fine structure (NEXAFS) spectroscopy to examine different TPD sample preparations in which differences in the thermodynamic stability of the glass are known. Density functional theory simulations of the NEXAFS spectra of TPD allow us to attribute spectroscopic differences to changes in the internal conformation of the TPD molecule and relate this conformation to the stability of the TPD glass. This provides a direct experimental measurement of the internal conformation of molecules forming an organic glass.
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Affiliation(s)
- Amara Zuhaib
- Department of Chemistry, University of Saskatchewan, Treaty Six Territory, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Stephen G Urquhart
- Department of Chemistry, University of Saskatchewan, Treaty Six Territory, Saskatoon, Saskatchewan S7N 5C9, Canada
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7
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Tourlakis GM, Adamopoulos SAT, Gavra IK, Milpanis AA, Tsagri LF, Pachygianni ASG, Chatzikokolis SS, Tsekouras AA. Sign flipping of spontaneous polarization in vapour-deposited films of small polar organic molecules. Phys Chem Chem Phys 2021; 23:14352-14362. [PMID: 34169950 DOI: 10.1039/d1cp01584b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Films of polar molecules vapour-deposited on sufficiently cold substrates are not only amorphous, but also exhibit charge polarization across their thickness. This is an effect known for 50 years, but it is very poorly understood and no mechanism exists in the literature that can explain and predict it. We investigated this bulk effect for 18 small organic molecules as a function of substrate temperature (30-130 K). We found that, as a rule, alcohol films have the negative end on the vacuum side at all temperatures. Alkyl acetates and toluene showed positive voltages which reached a maximum around the middle of the temperature range investigated. Tetrahydrofuran showed positive voltages which dropped with increasing deposition temperature. Diethyl ether, acetone, propanal, and butanal showed positive film voltages at low temperatures, negative at intermediate temperatures and again positive voltages at higher temperatures. In all cases, film voltages were monitored during heating leading to film evaporation. Film voltages were irreversibly eliminated before film elimination, but voltage profiles during temperature ramps differed vastly depending on compound and deposition temperature. In general, there was a gradual voltage reduction, but propanal, butanal, and diethyl ether showed a change in voltage sign during temperature ramp in films deposited at low temperatures. All these data expand substantially the experimental information regarding spontaneous polarization in vapour-deposited films, but still require complementary measurements as well as numerical simulations for a detailed explanation of the phenomenon.
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Affiliation(s)
- Georgios M Tourlakis
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
| | - Sotirios Alexandros T Adamopoulos
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
| | - Irini K Gavra
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
| | - Alexandros A Milpanis
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
| | - Liveria F Tsagri
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
| | - Aikaterini Sofia G Pachygianni
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
| | - Stylianos S Chatzikokolis
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
| | - Athanassios A Tsekouras
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
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8
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Gainaru C, Nelson H, Huebinger J, Grabenbauer M, Böhmer R. Suppression of Orientational Correlations in the Viscous-Liquid State of Hyperquenched Pressure-Densified Glycerol. PHYSICAL REVIEW LETTERS 2020; 125:065503. [PMID: 32845696 DOI: 10.1103/physrevlett.125.065503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
Glycerol pressurized to 2 kbar and hyperquenched from the bulk liquid at rates of about -10 000 K/s, has been frozen to an extreme out-of-equilibrium state. As compared to conventionally cooled melts, the resulting material exhibits lower orientational correlations, enabling the observation of a secondary relaxation peak in the ambient-pressure dielectric response. The hyperquenching rather than the pressurizing part of the preparation protocol induces the observed structural changes. These vanish entirely only well above the glass transition temperature of the equilibrium liquid and are evidence for strong similarities between hyperquenched and vapor-deposited glass formers.
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Affiliation(s)
- Catalin Gainaru
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Helge Nelson
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Jan Huebinger
- Max Planck-Institut für molekulare Physiologie, 44227 Dortmund, Germany
| | | | - Roland Böhmer
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
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9
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Holt AP, Fragiadakis D, Roland CM. Pressure densified 1,3,5-tri(1-naphthyl)benzene glass. I. Volume recovery and physical aging. J Chem Phys 2019; 151:184502. [PMID: 31731837 DOI: 10.1063/1.5122765] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The effects of pressure densification on 1,3,5-tri(1-naphthyl)benzene (TNB) are assessed from volumetric and calorimetric measurements. The pressure densified glass (PDG) has higher density than conventional glass (CG), but unlike ultrastable TNB glass prepared using vapor deposition which also has elevated density, TNB PDG exhibits higher enthalpy and lower thermal stability than when formed at ambient pressure. PDG also exhibits anomalous physical aging. Rather than evolving monotonically toward the equilibrium density, there is an overshoot to a lower density state. Only when the density of the PDG becomes equivalent to the corresponding CG does the density begin a slow approach toward equilibrium.
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Affiliation(s)
- A P Holt
- Naval Research Laboratory, Chemistry Division, Washington, DC 20375-5342, USA
| | - D Fragiadakis
- Naval Research Laboratory, Chemistry Division, Washington, DC 20375-5342, USA
| | - C M Roland
- Naval Research Laboratory, Chemistry Division, Washington, DC 20375-5342, USA
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10
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Wu S, Wang D, Zhong Y, Fang X, Chen Y, Jiang H, Li C, Wang Y. Dynamic characterization of structural relaxation in V 2O 5-P 2O 5 bulk oxide glass. Phys Chem Chem Phys 2019; 21:14879-14886. [PMID: 31232405 DOI: 10.1039/c9cp01322a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In oxide glasses, the microscopic hidden flow and the structural origin of the glass-to-liquid transition (GLT) are unclear due to the lack of detailed structural information. Herein, we investigate the evolution of the microscopic localized flow during GLT in a V2O5-P2O5 bulk oxide glass (BOG) by combining differential scanning calorimetry, temperature- and frequency-dependent bending experiments and stress relaxation spectra. The characteristic changes, their intrinsic correlations with the GLT process and the complete relaxation process are discussed in detail. We have observed three relaxation stages in the V2O5-P2O5 bulk oxide glass. Stage (I) corresponds to the nano-scale liquid-like movement with reversible activation of flow units. Stage (II) refers to the cooperative interaction of α and β relaxation, whereas stage (III) represents the glass transition process. In the frequency spectra, we have obtained a different result with metallic glasses by using a quasi-point defect model. When T < 480 K (Tβ), the correlation factor χ related to the quasi-point defect concentration is low and nearly constant, whereas, for T > 480 K (Tβ), χ shows a linear relationship with temperature. The present study provides useful insights to describe the relationship between the architecture of local atomic arrangements and mechanical properties of oxide glass.
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Affiliation(s)
- Shaolai Wu
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, 570228, P. R. China. and School of Physics and Electronic Engineering, Hainan Normal University, Haikou, 571158, China. and Special Glass Key Lab of Hainan Province, Haikou, 570228, P. R. China
| | - Debo Wang
- School of Physics and Electronic Engineering, Hainan Normal University, Haikou, 571158, China.
| | - Yuyong Zhong
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, 570228, P. R. China. and Special Glass Key Lab of Hainan Province, Haikou, 570228, P. R. China
| | - Xiaohui Fang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, 570228, P. R. China. and Special Glass Key Lab of Hainan Province, Haikou, 570228, P. R. China
| | - Yongjun Chen
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, 570228, P. R. China.
| | - Hong Jiang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, 570228, P. R. China. and Special Glass Key Lab of Hainan Province, Haikou, 570228, P. R. China
| | - Changjiu Li
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, 570228, P. R. China. and Special Glass Key Lab of Hainan Province, Haikou, 570228, P. R. China
| | - Yizhen Wang
- School of Physics and Electronic Engineering, Hainan Normal University, Haikou, 571158, China.
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11
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Pal SK, Chandel N, Mehta N. Synthesis and thermal characterization of novel phase change materials (PCMs) of the Se-Te-Sn-Ge (STSG) multi-component system: calorimetric studies of the glass/crystal phase transition. Dalton Trans 2019; 48:4719-4729. [PMID: 30900720 DOI: 10.1039/c8dt03729a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
According to recent literature, germanium-containing chalcogenide glasses (ChGs) show improvement in thermal stability and glass-forming ability because of the self-organization of the glass network towards a more rigid structure. The Ge-containing ChGs play a potential role as PCMs in phase-change optical memory (PCOM) applications. This endeavor reports the synthesis of some novel PCMs with Ge as the chemical modifier to improve the kinetic parameters of glass/crystal phase transition. The compositional variation of the various kinetic parameters in the present STSG chalcogen-rich non-oxide glasses Se78-yGeyTe20Sn2 (0 ≤ y ≤ 6) has been studied by means of the state-of-the-art differential scanning calorimetric (DSC) technique in the non-isothermal mode. The thermally assisted glass transition and crystallization phenomena have been investigated by examining the variation in various kinetic parameters like the characteristic kinetic temperatures (glass transition temperature Tg, on-set crystallization temperature To and peak crystallization temperature Tc), the activation energies involved in both phenomena, the thermal stability factor S and the glass-forming ability (GFA). The thermal stability factor S and GFA increase appreciably at higher concentrations of Ge as a signature of stiffness transition followed by the self-organization of the corner-sharing and the edge-sharing arrangements of the GeSe4 phase.
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Affiliation(s)
- Shiv Kumar Pal
- Physics Department, Institute of Science, Banaras Hindu University, Varanasi-221005, India.
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12
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Bagchi K, Jackson NE, Gujral A, Huang C, Toney MF, Yu L, de Pablo JJ, Ediger MD. Origin of Anisotropic Molecular Packing in Vapor-Deposited Alq3 Glasses. J Phys Chem Lett 2019; 10:164-170. [PMID: 30582803 DOI: 10.1021/acs.jpclett.8b03582] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Anisotropic molecular packing is a key feature that makes glasses prepared by physical vapor deposition (PVD) unique materials, warranting a mechanistic understanding of how a PVD glass attains its structure. To this end, we use X-ray scattering and ellipsometry to characterize the structure of PVD glasses of tris(8-hydroxyquinoline) aluminum (Alq3), a molecule used in organic electronics, and compare our results to simulations of its supercooled liquid. X-ray scattering reveals a tendency for molecular layering in Alq3 glasses that depends upon the substrate temperature during deposition and the deposition rate. Simulations reveal that the Alq3 supercooled liquid, like liquid metals, exhibits surface layering. We propose that the layering in Alq3 glasses observed here as well as the previously reported bulk dipole orientation are inherited from the surface structure of the supercooled liquid. This work significantly advances our understanding of the mechanism governing the formation of anisotropic structure in PVD glasses.
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Affiliation(s)
- Kushal Bagchi
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Nicholas E Jackson
- Institute for Molecular Engineering , University of Chicago , Chicago , Illinois 60637 , United States
- Institute for Molecular Engineering , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Ankit Gujral
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Chengbin Huang
- School of Pharmacy , University of Wisconsin-Madison , 777 Highland Avenue , Madison , Wisconsin 53705-2222 , United States
| | - Michael F Toney
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Lian Yu
- School of Pharmacy , University of Wisconsin-Madison , 777 Highland Avenue , Madison , Wisconsin 53705-2222 , United States
| | - Juan J de Pablo
- Institute for Molecular Engineering , University of Chicago , Chicago , Illinois 60637 , United States
- Institute for Molecular Engineering , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - M D Ediger
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
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13
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Stuart BW, Grant CA, Stan GE, Popa AC, Titman JJ, Grant DM. Gallium incorporation into phosphate based glasses: Bulk and thin film properties. J Mech Behav Biomed Mater 2018; 82:371-382. [PMID: 29656232 DOI: 10.1016/j.jmbbm.2018.03.041] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 03/28/2018] [Accepted: 03/29/2018] [Indexed: 12/27/2022]
Abstract
The osteogenic ions Ca2+, P5+, Mg2+, and antimicrobial ion Ga3+ were homogenously dispersed into a 1.45 µm thick phosphate glass coating by plasma assisted sputtering onto commercially pure grade titanium. The objective was to deliver therapeutic ions in orthopaedic/dental implants such as cementeless endoprostheses or dental screws. The hardness 4.7 GPa and elastic modulus 69.7 GPa, of the coating were comparable to plasma sprayed hydroxyapatite/dental enamel, whilst superseding femoral cortical bone. To investigate the manufacturing challenge of translation from a target to vapour condensed coating, structural/compositional properties of the target (P51MQ) were compared to the coating (P40PVD) and a melt-quenched equivalent (P40MQ). Following condensation from P51MQ to P40PVD, P2O5 content reduced from 48.9 to 40.5 mol%. This depolymerisation and reduction in the P-O-P bridging oxygen content as determined by 31P NMR, FTIR and Raman spectroscopy techniques was attributed to a decrease in the P2O5 network former and increases in alkali/alkali-earth cations. P40PVD appeared denser (3.47 vs. 2.70 g cm-3) and more polymerised than it's compositionally equivalent P40MQ, showing that structure/ mechanical properties were affected by manufacturing route.
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Affiliation(s)
- Bryan W Stuart
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, UK.
| | - Colin A Grant
- School of Chemistry and Biosciences, University of Bradford, BD7 1DP, UK
| | - George E Stan
- National Institute of Materials Physics, Magurele, Ilfov, Romania
| | - Adrian C Popa
- National Institute of Materials Physics, Magurele, Ilfov, Romania; Army Centre for Medical Research, RO-010195 Bucharest, Romania
| | | | - David M Grant
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, UK
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14
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Tournier RF. Predicting glass-to-glass and liquid-to-liquid phase transitions in supercooled water using classical nucleation theory. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2017.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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15
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Ngai KL, Wang LM, Yu HB. Relating Ultrastable Glass Formation to Enhanced Surface Diffusion via the Johari-Goldstein β-Relaxation in Molecular Glasses. J Phys Chem Lett 2017; 8:2739-2744. [PMID: 28585827 DOI: 10.1021/acs.jpclett.7b01192] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Glasses are materials essential for modern technology; they are usually prepared by cooling liquids. Recently, novel ultrastable glasses (SGs) with extraordinary thermodynamic and kinetic stability have been created by vapor deposition at appropriate substrate temperatures. However, the underlying mechanism for the formation of SGs is still not established. For most of the molecular SGs created so far, we demonstrate that the formation of SGs is closely related to the Johari-Goldstein β-relaxation from the fact that the lowest substrate temperatures possible for the formation of SGs match the secondary glass-transition temperatures, where the β-relaxation time reaches 103 s. Theoretically the β-relaxation time via the primitive relaxation time of the coupling model has proven capable of accounting for the enhancement of molecular mobility at the surface. Thus our findings provide evidence to support that the immense enhancement of molecular diffusion at the surface is critical for the formation of SGs. The result has implications in the design and fabrication of SGs.
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Affiliation(s)
- K L Ngai
- CNR-IPCF, Universita di Pisa , Largo B. Pontecorvo 3, I-56127 Pisa, Italy
- State Key Lab of Metastable Materials Science and Technology, and College of Materials Science and Engineering, Yanshan University , Qinhuangdao, Hebei 066004, China
| | - Li-Min Wang
- State Key Lab of Metastable Materials Science and Technology, and College of Materials Science and Engineering, Yanshan University , Qinhuangdao, Hebei 066004, China
| | - Hai-Bin Yu
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology , WuHan, Hubei 430074, China
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16
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Tylinski M, Beasley MS, Chua YZ, Schick C, Ediger MD. Limited surface mobility inhibits stable glass formation for 2-ethyl-1-hexanol. J Chem Phys 2017; 146:203317. [DOI: 10.1063/1.4977787] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- M. Tylinski
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, USA
| | - M. S. Beasley
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, USA
| | - Y. Z. Chua
- Institute of Physics, University of Rostock, Albert-Einstein-Str. 23-24, 18051 Rostock, Germany and Competence Centre CALOR, Faculty of Interdisciplinary Research, University of Rostock, Albert-Einstein-Str. 25, 18051 Rostock, Germany
| | - C. Schick
- Institute of Physics, University of Rostock, Albert-Einstein-Str. 23-24, 18051 Rostock, Germany and Competence Centre CALOR, Faculty of Interdisciplinary Research, University of Rostock, Albert-Einstein-Str. 25, 18051 Rostock, Germany
| | - M. D. Ediger
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, USA
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17
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Laventure A, Gujral A, Lebel O, Pellerin C, Ediger MD. Influence of Hydrogen Bonding on the Kinetic Stability of Vapor-Deposited Glasses of Triazine Derivatives. J Phys Chem B 2017; 121:2350-2358. [DOI: 10.1021/acs.jpcb.6b12676] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Audrey Laventure
- Département
de chimie, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Québec H3C 3J7, Canada
| | - Ankit Gujral
- Department
of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Olivier Lebel
- Department
of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ontario K7K 7B4, Canada
| | - Christian Pellerin
- Département
de chimie, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Québec H3C 3J7, Canada
| | - M. D. Ediger
- Department
of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
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18
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Gómez J, Gujral A, Huang C, Bishop C, Yu L, Ediger MD. Nematic-like stable glasses without equilibrium liquid crystal phases. J Chem Phys 2017; 146:054503. [DOI: 10.1063/1.4974829] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Jaritza Gómez
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Ankit Gujral
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Chengbin Huang
- School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, Wisconsin 53705-2222, USA
| | - Camille Bishop
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Lian Yu
- School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, Wisconsin 53705-2222, USA
| | - M. D. Ediger
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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19
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Ràfols-Ribé J, Gonzalez-Silveira M, Rodríguez-Tinoco C, Rodríguez-Viejo J. The role of thermodynamic stability in the characteristics of the devitrification front of vapour-deposited glasses of toluene. Phys Chem Chem Phys 2017; 19:11089-11097. [DOI: 10.1039/c7cp00741h] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Glass stability and molecular shape affect the transformation mechanism of vapour deposited glasses.
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Affiliation(s)
- Joan Ràfols-Ribé
- Grup de Nanomaterials i Microsistemes
- Physics Department
- Universtitat Autònoma de Barcelona
- 08193 Bellaterra
- Spain
| | - Marta Gonzalez-Silveira
- Grup de Nanomaterials i Microsistemes
- Physics Department
- Universtitat Autònoma de Barcelona
- 08193 Bellaterra
- Spain
| | - Cristian Rodríguez-Tinoco
- Grup de Nanomaterials i Microsistemes
- Physics Department
- Universtitat Autònoma de Barcelona
- 08193 Bellaterra
- Spain
| | - Javier Rodríguez-Viejo
- Grup de Nanomaterials i Microsistemes
- Physics Department
- Universtitat Autònoma de Barcelona
- 08193 Bellaterra
- Spain
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20
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Zografi G, Newman A. Interrelationships Between Structure and the Properties of Amorphous Solids of Pharmaceutical Interest. J Pharm Sci 2017; 106:5-27. [DOI: 10.1016/j.xphs.2016.05.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 04/27/2016] [Accepted: 05/03/2016] [Indexed: 10/21/2022]
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21
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Andersson O, Johari GP. Sub-T g features of glasses formed by cooling glycerol under pressure - Additional incompatibility of vibrational with configurational states in the depressurized, high density glass. J Chem Phys 2016; 145:204506. [PMID: 27908124 DOI: 10.1063/1.4968019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The vibrational state of a glass is naturally incompatible with its configurational state, which makes the glass structurally unstable. When a glass is kept at constant temperature, both the vibrational and configurational states of a glass change with time until it becomes metastable (equilibrium) liquid and the two states become compatible. The process, known as structural relaxation, occurs at a progressively higher rate during heating, and the properties of a glass change accordingly. We add to this incompatibility by depressurizing a glass that had been formed by cooling a liquid under a high pressure, p, and then investigate the effects of the added incompatibility by studying thermal conductivity, κ, and the heat capacity per unit volume ρCp of the depressurized glass. We use glycerol for the purpose and study first the changes in the features of κ and of ρCp during glass formation on cooling under a set of different p. We then partially depressurize the glass and study the effect of the p-induced instability on the features of κ and ρCp as the glass is isobarically heated to the liquid state. At a given low p, the glass configuration that was formed by cooling at high-p had a higher κ than the glass configuration that was formed by cooling at a low p. The difference is more when the glass is formed at a higher p and/or is depressurized to a lower p. On heating at a low p, its κ decreases before its glass-liquid transition range is reached. The effect is the opposite of the increase in κ observed on heating a glass at the same p under which it was formed. It is caused by thermally assisted loss of the added incompatibility of configurational and vibrational states of a high-p formed glass kept at low p. If a glass formed under a low-p is pressurized and then heated under high p, it would show the opposite effect, i.e., its κ would first increase to its high p value before its glass-to-liquid transition range.
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Affiliation(s)
- Ove Andersson
- Department of Physics, Umeå University, 901 87 Umeå, Sweden
| | - G P Johari
- Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7, Canada
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22
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Helfferich J, Lyubimov I, Reid D, de Pablo JJ. Inherent structure energy is a good indicator of molecular mobility in glasses. SOFT MATTER 2016; 12:5898-5904. [PMID: 27334679 DOI: 10.1039/c6sm00810k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Glasses produced via physical vapor deposition can display greater kinetic stability and lower enthalpy than glasses prepared by liquid cooling. While the reduced enthalpy has often been used as a measure of the stability, it is not obvious whether dynamic measures of stability provide the same view. Here, we study dynamics in vapor-deposited and liquid-cooled glass films using molecular simulations of a bead-spring polymer model as well as a Lennard-Jones binary mixture in two and three dimensions. We confirm that the dynamics in vapor-deposited glasses is indeed slower than in ordinary glasses. We further show that the inherent structure energy is a good reporter of local dynamics, and that aged systems and glasses prepared by cooling at progressively slower rates exhibit the same behavior as vapor-deposited materials when they both have the same inherent structure energy. These findings suggest that the stability inferred from measurements of the energy is also manifested in dynamic observables, and they strengthen the view that vapor deposition processes provide an effective strategy for creation of stable glasses.
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Affiliation(s)
- Julian Helfferich
- Institute for Molecular Engineering, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA.
| | - Ivan Lyubimov
- Institute for Molecular Engineering, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA.
| | - Daniel Reid
- Institute for Molecular Engineering, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA.
| | - Juan J de Pablo
- Institute for Molecular Engineering, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA. and Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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23
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Nagoe A, Oguni M, Fujimori H. Low-temperature heat capacities of confined liquid benzene, implying the behavior of ordinary bulk liquids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:455103. [PMID: 26490197 DOI: 10.1088/0953-8984/27/45/455103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Isobaric heat capacities C p of benzene confined in silica MCM-41 mesopores with average diameters equal to and smaller than 2.9 nm were measured by precise adiabatic calorimetry. The confined benzene samples revealed no thermal anomaly due to crystallization/fusion and vitrified at low temperatures. The C p curves displayed a hump and a considerably quick decrease on the low-temperature side of the hump as the pore diameter increased. The enthalpy-relaxation effects observed on intermittent heating showed that the anomaly of the C p hump and quick decrease is not assigned to a glass transition. The bend in the temperature dependence of density reported previously was interpreted as corresponding to the quick decrease in C p . We concluded that the anomalous C p and density behaviors originated from the ordering/excitation in the configurational state, close to the ground state, of confined molecular aggregate and proposed a scenario that explains the general C p curves of ordinary bulk supercooled liquids in equilibrium at low temperatures below the glass-transition temperatures.
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Affiliation(s)
- A Nagoe
- Research Center for Structural Thermodynamics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
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24
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25
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Yu HB, Tylinski M, Guiseppi-Elie A, Ediger MD, Richert R. Suppression of β Relaxation in Vapor-Deposited Ultrastable Glasses. PHYSICAL REVIEW LETTERS 2015; 115:185501. [PMID: 26565473 DOI: 10.1103/physrevlett.115.185501] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Indexed: 06/05/2023]
Abstract
Glassy materials display numerous important properties which relate to the presence and intensity of the secondary (β) relaxations that dominate the dynamics below the glass transition temperature. However, experimental protocols such as annealing allow little control over the β relaxation for most glasses. Here we report on the β relaxation of toluene in highly stable glasses prepared by physical vapor deposition. At conditions that generate the highest kinetic stability, about 70% of the β relaxation intensity is suppressed, indicating the proximity of this state to the long-sought "ideal glass." While preparing such a state via deposition takes less than an hour, it would require ~3500 years of annealing an ordinary glass to obtain similarly suppressed dynamics.
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Affiliation(s)
- H B Yu
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA
| | - M Tylinski
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - A Guiseppi-Elie
- Department of Biomedical Engineering, The Dwight Look College of Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - M D Ediger
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - R Richert
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA
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26
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Chua YZ, Ahrenberg M, Tylinski M, Ediger MD, Schick C. How much time is needed to form a kinetically stable glass? AC calorimetric study of vapor-deposited glasses of ethylcyclohexane. J Chem Phys 2015; 142:054506. [PMID: 25662653 DOI: 10.1063/1.4906806] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Glasses of ethylcyclohexane produced by physical vapor deposition have been characterized by in situ alternating current chip nanocalorimetry. Consistent with previous work on other organic molecules, we observe that glasses of high kinetic stability are formed at substrate temperatures around 0.85 Tg, where Tg is the conventional glass transition temperature. Ethylcyclohexane is the least fragile organic glass-former for which stable glass formation has been established. The isothermal transformation of the vapor-deposited glasses into the supercooled liquid state was also measured. At seven substrate temperatures, the transformation time was measured for glasses prepared with deposition rates across a range of four orders of magnitude. At low substrate temperatures, the transformation time is strongly dependent upon deposition rate, while the dependence weakens as Tg is approached from below. These data provide an estimate for the surface equilibration time required to maximize kinetic stability at each substrate temperature. This surface equilibration time is much smaller than the bulk α-relaxation time and within two orders of magnitude of the β-relaxation time of the ordinary glass. Kinetically stable glasses are formed even for substrate temperatures below the Vogel and the Kauzmann temperatures. Surprisingly, glasses formed in the limit of slow deposition at the lowest substrate temperatures are not as kinetically stable as those formed near 0.85 Tg.
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Affiliation(s)
- Y Z Chua
- Institute of Physics, University of Rostock, Wismarsche Str. 43-45, 18051 Rostock, Germany
| | - M Ahrenberg
- Institute of Physics, University of Rostock, Wismarsche Str. 43-45, 18051 Rostock, Germany
| | - M Tylinski
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M D Ediger
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - C Schick
- Institute of Physics, University of Rostock, Wismarsche Str. 43-45, 18051 Rostock, Germany
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27
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Walters DM, Richert R, Ediger MD. Thermal stability of vapor-deposited stable glasses of an organic semiconductor. J Chem Phys 2015; 142:134504. [PMID: 25854250 DOI: 10.1063/1.4916649] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Vapor-deposited organic glasses can show enhanced kinetic stability relative to liquid-cooled glasses. When such stable glasses of model glassformers are annealed above the glass transition temperature Tg, they lose their thermal stability and transform into the supercooled liquid via constant velocity propagating fronts. In this work, we show that vapor-deposited glasses of an organic semiconductor, N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD), also transform via propagating fronts. Using spectroscopic ellipsometry and a new high-throughput annealing protocol, we measure transformation front velocities for TPD glasses prepared with substrate temperatures (TSubstrate) from 0.63 to 0.96 Tg, at many different annealing temperatures. We observe that the front velocity varies by over an order of magnitude with TSubstrate, while the activation energy remains constant. Using dielectric spectroscopy, we measure the structural relaxation time of supercooled TPD. We find that the mobility of the liquid and the structure of the glass are independent factors in controlling the thermal stability of TPD films. In comparison to model glassformers, the transformation fronts of TPD have similar velocities and a similar dependence on TSubstrate, suggesting universal behavior. These results may aid in designing active layers in organic electronic devices with improved thermal stability.
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Affiliation(s)
- Diane M Walters
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Ranko Richert
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA
| | - M D Ediger
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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28
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Bhattacharya D, Sadtchenko V. Vapor-deposited non-crystalline phase vs ordinary glasses and supercooled liquids: Subtle thermodynamic and kinetic differences. J Chem Phys 2015; 142:164510. [PMID: 25933777 DOI: 10.1063/1.4918745] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
| | - Vlad Sadtchenko
- Chemistry Department, The George Washington University, Washington, DC 20052, USA
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29
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Dalal SS, Ediger MD. Influence of Substrate Temperature on the Transformation Front Velocities That Determine Thermal Stability of Vapor-Deposited Glasses. J Phys Chem B 2015; 119:3875-82. [DOI: 10.1021/jp512905a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Shakeel S. Dalal
- Department
of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - M. D. Ediger
- Department
of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
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30
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Rodríguez-Tinoco C, Gonzalez-Silveira M, Ràfols-Ribé J, Lopeandía AF, Rodríguez-Viejo J. Transformation kinetics of vapor-deposited thin film organic glasses: the role of stability and molecular packing anisotropy. Phys Chem Chem Phys 2015; 17:31195-201. [DOI: 10.1039/c5cp04692k] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The growth front velocity of indomethacin glasses depends on deposition conditions but is not unambigously determined by its thermodynamic stability when the structure is not completely isotropic.
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Affiliation(s)
- Cristian Rodríguez-Tinoco
- Grup de Nanomaterials i Microsistemes
- Physics Department
- Universitat Autònoma de Barcelona
- 08193 Bellaterra
- Spain
| | - Marta Gonzalez-Silveira
- Grup de Nanomaterials i Microsistemes
- Physics Department
- Universitat Autònoma de Barcelona
- 08193 Bellaterra
- Spain
| | - Joan Ràfols-Ribé
- Grup de Nanomaterials i Microsistemes
- Physics Department
- Universitat Autònoma de Barcelona
- 08193 Bellaterra
- Spain
| | - Aitor F. Lopeandía
- Grup de Nanomaterials i Microsistemes
- Physics Department
- Universitat Autònoma de Barcelona
- 08193 Bellaterra
- Spain
| | - Javier Rodríguez-Viejo
- Grup de Nanomaterials i Microsistemes
- Physics Department
- Universitat Autònoma de Barcelona
- 08193 Bellaterra
- Spain
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31
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Omori K, Nakayama H, Ishii K. Diversity of the Dimer Structures of Toluene: Exploration by the GRRM Method. CHEM LETT 2014. [DOI: 10.1246/cl.140695] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Kio Omori
- Department of Chemistry, Gakushuin University
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32
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Bhattacharya D, Sadtchenko V. Enthalpy and high temperature relaxation kinetics of stable vapor-deposited glasses of toluene. J Chem Phys 2014; 141:094502. [DOI: 10.1063/1.4893716] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
| | - Vlad Sadtchenko
- Chemistry Department, The George Washington University, Washington, DC 20052, USA
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