1
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Yin J, Forrest JA. Film Thickness Dependent Stability and Glass Transition Temperature of Polymer Films Produced by Physical Vapor Deposition. PHYSICAL REVIEW LETTERS 2023; 130:168101. [PMID: 37154633 DOI: 10.1103/physrevlett.130.168101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 02/12/2023] [Accepted: 03/17/2023] [Indexed: 05/10/2023]
Abstract
We report measurements of the onset temperature of rejuvenation, T_{onset}, and the fictive temperature, T_{f}, for ultrathin stable polystyrene with thicknesses from 10 to 50 nm prepared by physical vapor deposition. We also measure the T_{g} of these glasses on the first cooling after rejuvenation as well as the density anomaly of the as-deposited material. Both the T_{g} in rejuvenated films and the T_{onset} in stable films decrease with decreasing film thickness. The T_{f} value increases for decreasing film thickness. The density increase typical of stable glasses also decreases with decreasing film thickness. Collectively, the results are consistent with a decrease in apparent T_{g} due to the existence of a mobile surface layer, as well as a decrease in the film stability as the thickness is decreased. The results provide the first self-consistent set of measurements of stability in ultrathin films of stable glass.
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Affiliation(s)
- Junjie Yin
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
| | - James A Forrest
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
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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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Tournier RF, Ojovan MI. Prediction of Second Melting Temperatures Already Observed in Pure Elements by Molecular Dynamics Simulations. MATERIALS 2021; 14:ma14216509. [PMID: 34772033 PMCID: PMC8585396 DOI: 10.3390/ma14216509] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/19/2021] [Accepted: 10/26/2021] [Indexed: 12/01/2022]
Abstract
A second melting temperature occurs at a temperature Tn+ higher than Tm in glass-forming melts after heating them from their glassy state. The melting entropy is reduced or increased depending on the thermal history and on the presence of antibonds or bonds up to Tn+. Recent MD simulations show full melting at Tn+ = 1.119Tm for Zr, 1.126Tm for Ag, 1.219Tm for Fe and 1.354Tm for Cu. The non-classical homogeneous nucleation model applied to liquid elements is based on the increase of the Lindemann coefficient with the heating rate. The glass transition at Tg and the nucleation temperatures TnG of glacial phases are successfully predicted below and above Tm. The glass transition temperature Tg increases with the heating rate up to Tn+. Melting and crystallization of glacial phases occur with entropy and enthalpy reductions. A universal law relating Tn+ and TnG around Tm shows that TnG cannot be higher than 1.293Tm for Tn+= 1.47Tm. The enthalpies and entropies of glacial phases have singular values, corresponding to the increase of percolation thresholds with Tg and TnG above the Scher and Zallen invariant at various heating and cooling rates. The G-phases are metastable up to Tn+ because the antibonds are broken by homogeneous nucleation of bonds.
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Affiliation(s)
- Robert F. Tournier
- UPR 3228 Centre National de la Recherche Scientifique, Laboratoire National des Champs Magnétiques Intenses, European Magnetic Field Laboratory, Institut National des Sciences Appliquées de Toulouse, Université Grenoble Alpes, F-31400 Toulouse, France
- Correspondence:
| | - Michael I. Ojovan
- Department of Materials, Imperial College London, London SW7 2AZ, UK;
- Department of Radiochemistry, Moscow State University, 119991 Moscow, Russia
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4
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Beasley MS, Kasting BJ, Tracy ME, Guiseppi-Elie A, Richert R, Ediger MD. Physical vapor deposition of a polyamorphic system: Triphenyl phosphite. J Chem Phys 2020; 153:124511. [PMID: 33003706 DOI: 10.1063/5.0019872] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In situ AC nanocalorimetry and dielectric spectroscopy were used to analyze films of vapor-deposited triphenyl phosphite. The goal of this work was to investigate the properties of vapor-deposited glasses of this known polyamorphic system and to determine which liquid is formed when the glass is heated. We find that triphenyl phosphite forms a kinetically stable glass when prepared at substrate temperatures of 0.75-0.95Tg, where Tg is the glass transition temperature. Regardless of the substrate temperature utilized during deposition of triphenyl phosphite, heating a vapor-deposited glass always forms the ordinary supercooled liquid (liquid 1). The identity of liquid 1 was confirmed by both the calorimetric signal and the shape and position of the dielectric spectra. For the purposes of comparison, the glacial phase of triphenyl phosphite (liquid 2) was prepared by the conventional method of annealing liquid 1. We speculate that these new results and previous work on vapor deposition of other polyamorphic systems can be explained by the free surface structure being similar to one polyamorph even in a temperature regime where the other polyamorph is more thermodynamically stable in the bulk.
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Affiliation(s)
- M S Beasley
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - B J Kasting
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M E Tracy
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - A Guiseppi-Elie
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - R 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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5
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Rodríguez-Tinoco C, Gonzalez-Silveira M, Ràfols-Ribé J, Vila-Costa A, Martinez-Garcia JC, Rodríguez-Viejo J. Surface-Bulk Interplay in Vapor-Deposited Glasses: Crossover Length and the Origin of Front Transformation. PHYSICAL REVIEW LETTERS 2019; 123:155501. [PMID: 31702315 DOI: 10.1103/physrevlett.123.155501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 07/24/2019] [Indexed: 06/10/2023]
Abstract
Thin film stable glasses transform into a liquid by a moving front that propagates from surfaces or interfaces with higher mobility. We use calorimetric data of vapor-deposited glasses of different thicknesses and stabilities to identify the role of glassy and liquid dynamics on the transformation process. By invoking the existence of an ultrathin intermediate layer whose transformation strongly depends on the properties of both the liquid and the glass, we show that the recovery to equilibrium is driven by the mismatch in the dynamics between glass and liquid. The lifetime of this intermediate layer associated with the moving front is the geometric mean between the bulk transformation time and the alpha relaxation time. Within this view, we explain the observed dependencies of the growth front velocity and the crossover length with both stability and temperature. Extrapolation of these results points towards ordinary thin film glasses transforming via a frontlike transformation mechanism if heated sufficiently fast, establishing a close connection between vapor-deposited and liquid-cooled glasses.
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Affiliation(s)
- Cristian Rodríguez-Tinoco
- Group of Nanomaterials and Microsystems, Physics Department, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Marta Gonzalez-Silveira
- Group of Nanomaterials and Microsystems, Physics Department, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Joan Ràfols-Ribé
- Group of Nanomaterials and Microsystems, Physics Department, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Ana Vila-Costa
- Group of Nanomaterials and Microsystems, Physics Department, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Julio Cesar Martinez-Garcia
- Group of Nanomaterials and Microsystems, Physics Department, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Javier Rodríguez-Viejo
- Group of Nanomaterials and Microsystems, Physics Department, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
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6
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Beasley MS, Bishop C, Kasting BJ, Ediger MD. Vapor-Deposited Ethylbenzene Glasses Approach "Ideal Glass" Density. J Phys Chem Lett 2019; 10:4069-4075. [PMID: 31269793 DOI: 10.1021/acs.jpclett.9b01508] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Spectroscopic ellipsometry was used to characterize vapor-deposited glasses of ethylbenzene (Tg = 115.7 K). For this system, previous calorimetric experiments have established that a transition to the ideal glass state is expected to occur near 101 K (the Kauzmann temperature, TK) if the low-temperature supercooled liquid has the properties expected based upon extrapolation from above Tg. Ethylbenzene glasses were vapor-deposited at substrate temperatures between 100 (∼0.86 Tg) and 116 K (∼Tg), using deposition rates of 0.02-2.1 nm/s. Down to 103 K, glasses prepared in the limit of low deposition rate have densities consistent with the extrapolated supercooled liquid. The highest density glass is within 0.15% of the density expected for the ideal glass. These results support the hypothesis that the extrapolated properties of supercooled ethylbenzene are correct to within just a few Kelvin of TK, consistent with the existence of a phase transition to an ideal glass state at TK.
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Affiliation(s)
- M S Beasley
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - C Bishop
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - B J Kasting
- 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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7
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Riechers B, Guiseppi-Elie A, Ediger MD, Richert R. Ultrastable and polyamorphic states of vapor-deposited 2-methyltetrahydrofuran. J Chem Phys 2019; 150:214502. [DOI: 10.1063/1.5091796] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
- Birte Riechers
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, 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 53705, USA
| | - Ranko Richert
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, USA
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8
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Cubeta US, Sadtchenko V. Glass softening kinetics in the limit of high heating rates. J Chem Phys 2019; 150:094508. [DOI: 10.1063/1.5046304] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ulyana S. Cubeta
- Chemistry Department, The George Washington University, Washington, District of Columbia 20052, USA
| | - Vlad Sadtchenko
- Chemistry Department, The George Washington University, Washington, District of Columbia 20052, USA
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9
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Oh-e M, Ogata H, Araoka F. Randomization and Constraint of Molecular Alignment and Orientation: Temperature-Dependent Anisotropy and Phase Transition in Vapor-Deposited Thin Films of an Organic Cross-Shaped Molecule. ACS OMEGA 2019; 4:39-47. [PMID: 31459310 PMCID: PMC6648730 DOI: 10.1021/acsomega.8b02560] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 12/14/2018] [Indexed: 05/29/2023]
Abstract
We observe potential randomization and constraint of molecular alignment and orientation in an organic semiconductor molecule with increasing temperature up to the phase-transition temperature. Variable-angle spectroscopic ellipsometry and second-harmonic generation are used to study the changes in the molecular alignment in vapor-deposited organic thin films as samples are heated and cooled in a cycle from room temperature to the phase-transition temperature. The films consist of sterically bulky and cross-shaped molecules, 2-cyano-9,10-di(2-naphthyl)anthracene, and the anisotropy of its two moieties is probed. Anisotropic molecular alignment with respect to the surface normal in as-deposited amorphous films changes with the film thickness, which increases slightly with increasing substrate temperature. Moreover, the axis near the long axis of the anthracene moiety changes significantly with respect to the surface normal from the magic angle to isotropic alignment, showing monotonically decreasing anisotropy. Interestingly, the anisotropy of the axis near the long axis of the anthracene moiety disappears before the phase-transition temperature. In contrast, the axis near the short axis of the anthracene moiety exhibits a notable characteristic change in the temperature-dependent alignment during the heating process; although the anisotropy initially decreases, it significantly increases as the temperature approaches the phase transition. At a certain temperature during heating, the film thickness shows a discontinuous jump, similar to a first phase transition, while the anisotropic molecular alignment completely disappears. During the cooling process after the phase transition, however, the properties of the films are irreversibly changed, and anisotropic molecular alignment is no longer observed; thus, the samples become completely isotropic.
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Affiliation(s)
- Masahito Oh-e
- Institute
of Photonics Technologies, Department of Electrical Engineering, National Tsing Hua University, 101 Sec. 2 Kuang-Fu Road, Hsinchu 30013, Taiwan
| | - Hidenori Ogata
- Institute
of Photonics Technologies, Department of Electrical Engineering, National Tsing Hua University, 101 Sec. 2 Kuang-Fu Road, Hsinchu 30013, Taiwan
| | - Fumito Araoka
- RIKEN
Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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10
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Kearns KL, Krzyskowski P, Devereaux Z. Using deposition rate to increase the thermal and kinetic stability of vapor-deposited hole transport layer glasses via a simple sublimation apparatus. J Chem Phys 2018; 146:203328. [PMID: 28571345 DOI: 10.1063/1.4979814] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Deposition rate is known to affect the relative stability of vapor-deposited glasses; slower rates give more stable materials due to enhanced mobility at the free surface of the film. Here we show that the deposition rate can affect both the thermodynamic and kinetic stabilities of N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD) and N,N'-di-[(1-naphthyl)-N,N'-diphenyl]-1,1'-biphenyl)-4,4'-diamine (NPD) glasses used as hole transport layers for organic light emitting diodes (OLEDs). A simple, low-vacuum glass sublimation apparatus and a high vacuum deposition chamber were used to deposit the glass. 50 μm thick films were deposited in the sublimation apparatus and characterized by differential scanning calorimetry while 75 nm thick films were prepared in the high vacuum chamber and studied by hot-stage spectroscopic ellipsometry (SE). The thermodynamic stability from both preparation chambers was consistent and showed that the fictive temperature (Tfictive) was more than 30 K lower than the conventional glass transition temperature (Tg) at the slowest deposition rates. The kinetic stability, measured as the onset temperature (Tonset) where the glass begins to transform into the supercooled liquid, was 16-17 K greater than Tg at the slowest rates. Tonset was systematically lower for the thin films characterized by SE and was attributed to the thickness dependent transformation of the glass into the supercooled liquid. These results show the first calorimetric characterization of the stability of glasses for OLED applications made by vapor deposition and the first direct comparison of deposition apparatuses as a function of the deposition rate. The ease of fabrication will create an opportunity for others to study the effect of deposition conditions on glass stability.
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Affiliation(s)
- Kenneth L Kearns
- Department of Chemistry, Saginaw Valley State University, University Center, Michigan 48710, USA
| | - Paige Krzyskowski
- Department of Chemistry, Saginaw Valley State University, University Center, Michigan 48710, USA
| | - Zachary Devereaux
- Department of Chemistry, Saginaw Valley State University, University Center, Michigan 48710, USA
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11
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Chua YZ, Young-Gonzales AR, Richert R, Ediger MD, Schick C. Dynamics of supercooled liquid and plastic crystalline ethanol: Dielectric relaxation and AC nanocalorimetry distinguish structural α- and Debye relaxation processes. J Chem Phys 2018; 147:014502. [PMID: 28688431 DOI: 10.1063/1.4991006] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Physical vapor deposition has been used to prepare glasses of ethanol. Upon heating, the glasses transformed into the supercooled liquid phase and then crystallized into the plastic crystal phase. The dynamic glass transition of the supercooled liquid is successfully measured by AC nanocalorimetry, and preliminary results for the plastic crystal are obtained. The frequency dependences of these dynamic glass transitions observed by AC nanocalorimetry are in disagreement with conclusions from previously published dielectric spectra of ethanol. Existing dielectric loss spectra have been carefully re-evaluated considering a Debye peak, which is a typical feature in the dielectric loss spectra of monohydroxy alcohols. The re-evaluated dielectric fits reveal a prominent dielectric Debye peak, a smaller and asymmetrically broadened peak, which is identified as the signature of the structural α-relaxation and a Johari-Goldstein secondary relaxation process. This new assignment of the dielectric processes is supported by the observation that the AC nanocalorimetry dynamic glass transition temperature, Tα, coincides with the dielectric structural α-relaxation process rather than the Debye process. The combined results from dielectric spectroscopy and AC nanocalorimetry on the plastic crystal of ethanol suggest the occurrence of a Debye process also in the plastic crystal phase.
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Affiliation(s)
- 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
| | - A R Young-Gonzales
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, USA
| | - R Richert
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, USA
| | - M D Ediger
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - 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
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12
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Beasley MS, Tylinski M, Chua YZ, Schick C, Ediger MD. Glasses of three alkyl phosphates show a range of kinetic stabilities when prepared by physical vapor deposition. J Chem Phys 2018; 148:174503. [DOI: 10.1063/1.5026505] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- M. S. Beasley
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M. Tylinski
- Department of Chemistry, Widener University, Chester, Pennsylvania 19013, USA
| | - Y. Z. Chua
- Institute of Physics, University of Rostock, Albert-Einstein-Str. 23-24, 18051 Rostock, Germany and Competence Center 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 Center 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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13
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Ràfols-Ribé J, Will PA, Hänisch C, Gonzalez-Silveira M, Lenk S, Rodríguez-Viejo J, Reineke S. High-performance organic light-emitting diodes comprising ultrastable glass layers. SCIENCE ADVANCES 2018; 4:eaar8332. [PMID: 29806029 PMCID: PMC5969811 DOI: 10.1126/sciadv.aar8332] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 04/10/2018] [Indexed: 05/20/2023]
Abstract
Organic light-emitting diodes (OLEDs) are one of the key solid-state light sources for various applications including small and large displays, automotive lighting, solid-state lighting, and signage. For any given commercial application, OLEDs need to perform at their best, which is judged by their device efficiency and operational stability. We present OLEDs that comprise functional layers fabricated as ultrastable glasses, which represent the thermodynamically most favorable and, thus, stable molecular conformation achievable nowadays in disordered solids. For both external quantum efficiencies and LT70 lifetimes, OLEDs with four different phosphorescent emitters show >15% enhancements over their respective reference devices. The only difference to the latter is the growth condition used for ultrastable glass layers that is optimal at about 85% of the materials' glass transition temperature. These improvements are achieved through neither material refinements nor device architecture optimization, suggesting a general applicability of this concept to maximize the OLED performance, no matter which specific materials are used.
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Affiliation(s)
- Joan Ràfols-Ribé
- Group of Nanomaterials and Microsystems, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Paul-Anton Will
- Dresden Integrated Center for Applied Physics and Photonic Materials and Institute for Applied Physics, Technische Universität Dresden (IAPP), 01187 Dresden, Germany
| | - Christian Hänisch
- Dresden Integrated Center for Applied Physics and Photonic Materials and Institute for Applied Physics, Technische Universität Dresden (IAPP), 01187 Dresden, Germany
| | - Marta Gonzalez-Silveira
- Group of Nanomaterials and Microsystems, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Simone Lenk
- Dresden Integrated Center for Applied Physics and Photonic Materials and Institute for Applied Physics, Technische Universität Dresden (IAPP), 01187 Dresden, Germany
| | - Javier Rodríguez-Viejo
- Group of Nanomaterials and Microsystems, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Sebastian Reineke
- Dresden Integrated Center for Applied Physics and Photonic Materials and Institute for Applied Physics, Technische Universität Dresden (IAPP), 01187 Dresden, Germany
- Corresponding author.
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14
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Ahrenberg M, Beck M, Neise C, Keßler O, Kragl U, Verevkin SP, Schick C. Vapor pressure of ionic liquids at low temperatures from AC-chip-calorimetry. Phys Chem Chem Phys 2018; 18:21381-90. [PMID: 27425628 DOI: 10.1039/c6cp01948j] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The very low vapor pressure of ionic liquids is challenging to measure. At elevated temperatures the liquids might start to decompose, and at relatively low temperatures the vapor pressure becomes too low to be measured by conventional methods. In this work we developed a highly sensitive method for mass loss determination at temperatures starting from 350 K. This technique is based on an alternating current calorimeter equipped with a chip sensor that consists of a free-standing SiNx-membrane (thickness <1 μm) and a measuring area with lateral dimensions of the order of 1 mm. A small droplet (diameter ca. 600 μm) of an ionic liquid is vaporized isothermally from the chip sensor in a vacuum-chamber. The surface-to-volume-ratio of such a droplet is large and the relative mass loss due to evaporation is therefore easy to monitor by the changing heat capacity (J K(-1)) of the remaining liquid. The vapor pressure is determined from the measured mass loss rates using the Langmuir equation. The method was successfully tested for the determination of the vapor pressure and the vaporization enthalpy of an archetypical ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIm][NTf2]). The data set created in this way in an extremely broad temperature range from 358 K to 780 K has allowed the estimation of the boiling temperature of [EMIm][NTf2]. The value (1120 ± 50) K should be considered as the first reliable boiling point of the archetypical ionic liquid obtained from experimental vapor pressures measured in the most possible close proximity to the normal boiling temperature.
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Affiliation(s)
- Mathias Ahrenberg
- Institute of Physics, University of Rostock, Albert-Einstein-Str. 23-24, 18059 Rostock, Germany.
| | - Martin Beck
- Faculty of Mechanical Engineering and Marine Technology, University of Rostock, Albert-Einstein-Str. 2, 18059 Rostock, Germany
| | - Christin Neise
- Institute of Chemistry, University of Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany
| | - Olaf Keßler
- Faculty of Mechanical Engineering and Marine Technology, University of Rostock, Albert-Einstein-Str. 2, 18059 Rostock, Germany and Competence Centre CALOR, Faculty of Interdisciplinary Research, University of Rostock, Albert-Einstein-Str. 25, 18059 Rostock, Germany
| | - Udo Kragl
- Institute of Chemistry, University of Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany and Competence Centre CALOR, Faculty of Interdisciplinary Research, University of Rostock, Albert-Einstein-Str. 25, 18059 Rostock, Germany
| | - Sergey P Verevkin
- Institute of Chemistry, University of Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany and Competence Centre CALOR, Faculty of Interdisciplinary Research, University of Rostock, Albert-Einstein-Str. 25, 18059 Rostock, Germany
| | - Christoph Schick
- Institute of Physics, University of Rostock, Albert-Einstein-Str. 23-24, 18059 Rostock, Germany. and Competence Centre CALOR, Faculty of Interdisciplinary Research, University of Rostock, Albert-Einstein-Str. 25, 18059 Rostock, Germany
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15
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Cangialosi D. Glass Transition and Physical Aging of Confined Polymers Investigated by Calorimetric Techniques. RECENT ADVANCES, TECHNIQUES AND APPLICATIONS 2018. [DOI: 10.1016/b978-0-444-64062-8.00013-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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16
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Affiliation(s)
- M. D. Ediger
- Department of Chemistry, University of Wisconsin-Madison,
1101 University Avenue, Madison, Wisconsin 53706, USA
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17
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Liu T, Exarhos AL, Alguire EC, Gao F, Salami-Ranjbaran E, Cheng K, Jia T, Subotnik JE, Walsh PJ, Kikkawa JM, Fakhraai Z. Birefringent Stable Glass with Predominantly Isotropic Molecular Orientation. PHYSICAL REVIEW LETTERS 2017; 119:095502. [PMID: 28949582 DOI: 10.1103/physrevlett.119.095502] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Indexed: 06/07/2023]
Abstract
Birefringence in stable glasses produced by physical vapor deposition often implies molecular alignment similar to liquid crystals. As such, it remains unclear whether these glasses share the same energy landscape as liquid-quenched glasses that have been aged for millions of years. Here, we produce stable glasses of 9-(3,5-di(naphthalen-1-yl)phenyl)anthracene molecules that retain three-dimensional shapes and do not preferentially align in a specific direction. Using a combination of angle- and polarization-dependent photoluminescence and ellipsometry experiments, we show that these stable glasses possess a predominantly isotropic molecular orientation while being optically birefringent. The intrinsic birefringence strongly correlates with increased density, showing that molecular ordering is not required to produce stable glasses or optical birefringence, and provides important insights into the process of stable glass formation via surface-mediated equilibration. To our knowledge, such novel amorphous packing has never been reported in the past.
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Affiliation(s)
- Tianyi Liu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Annemarie L Exarhos
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Ethan C Alguire
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Feng Gao
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | | | - Kevin Cheng
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Tiezheng Jia
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Joseph E Subotnik
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Patrick J Walsh
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - James M Kikkawa
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Zahra Fakhraai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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18
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Cubeta U, Bhattacharya D, Sadtchenko V. Communication: Surface-facilitated softening of ordinary and vapor-deposited glasses. J Chem Phys 2017; 147:071101. [DOI: 10.1063/1.4997038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ulyana Cubeta
- Chemistry Department, The George Washington University, Washington, DC 20052, USA
| | | | - Vlad Sadtchenko
- Chemistry Department, The George Washington University, Washington, DC 20052, USA
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19
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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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20
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Zhang W, Douglas JF, Starr FW. Dynamical heterogeneity in a vapor-deposited polymer glass. J Chem Phys 2017; 146:203310. [DOI: 10.1063/1.4976542] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Wengang Zhang
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459-0155, USA
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Francis W. Starr
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459-0155, USA
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21
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Boucher VM, Cangialosi D, Alegría A, Colmenero J. Complex nonequilibrium dynamics of stacked polystyrene films deep in the glassy state. J Chem Phys 2017; 146:203312. [DOI: 10.1063/1.4977207] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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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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23
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Natesan H, Bischof JC. Multiscale Thermal Property Measurements for Biomedical Applications. ACS Biomater Sci Eng 2017; 3:2669-2691. [PMID: 33418696 DOI: 10.1021/acsbiomaterials.6b00565] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Bioheat transfer-based innovations in health care include applications such as focal treatments for cancer and cardiovascular disease and the preservation of tissues and organs for transplantation. In these applications, the ability to preserve or destroy a biomaterial is directly dependent on its temperature history. Thus, thermal measurement and modeling are necessary to either avoid or induce the injury required. In this review paper, we will first define and discuss thermal conductivity and calorimetric measurements of biomaterials in the cryogenic (<-40 °C), subzero (<0 °C), hypothermic (<37 °C), and hyperthermic (>37 °C) regimes. For thermal conductivity measurements, we review the use of 3ω and laser flash techniques for measurement of thermal conductivity in thin (1 μm-2 mm thick), anisotropic, and/or multilayered tissues. At the nanoscale, we review the use of pump-probe and scanning probe methods to measure thermal conductivity at short temporal scales (10 ps-100 ns) and spatial scales (1 nm-1 μm), particularly in the coating and surrounding medium around metallic nanoparticles (1 nm-20 nm). For calorimetric techniques, we review differential scanning calorimetry (DSC), which is intrinsically at the microscale (e.g., tissue pieces or millions of cells in media). DSC is used with large sample mass (∼3-100 mg) over wide temperature ranges (-180 to 750 °C) with low-temperature scanning rates (<750 °C/min). The need to assess smaller samples at higher rates has led to the development of nanocalorimetry on a silicon based membrane. Here the sample weight is as low as 10 ng, thereby allowing ultra-rapid heating rates (∼1 × 107 C/min). Finally, we discuss various opportunities that are driving the need for new micro- and nanoscale thermal measurements.
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Affiliation(s)
- Harishankar Natesan
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - John C Bischof
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
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24
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Ngai KL, Paluch M, Rodríguez-Tinoco C. Why is surface diffusion the same in ultrastable, ordinary, aged, and ultrathin molecular glasses? Phys Chem Chem Phys 2017; 19:29905-29912. [DOI: 10.1039/c7cp05357f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The primitive/JG relaxation explains the same surface diffusion coefficient in ordinary, ultrastable and thin film glasses of OTP and TPD.
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Affiliation(s)
- K. L. Ngai
- Silesian Center for Education and Interdisciplinary Research
- 41-500 Chorzow
- Poland
| | - Marian Paluch
- Silesian Center for Education and Interdisciplinary Research
- 41-500 Chorzow
- Poland
- Institute of Physics
- University of Silesia
| | - Cristian Rodríguez-Tinoco
- Silesian Center for Education and Interdisciplinary Research
- 41-500 Chorzow
- Poland
- Institute of Physics
- University of Silesia
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25
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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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26
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Tylinski M, Chua YZ, Beasley MS, Schick C, Ediger MD. Vapor-deposited alcohol glasses reveal a wide range of kinetic stability. J Chem Phys 2016; 145:174506. [DOI: 10.1063/1.4966582] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- M. Tylinski
- 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
| | - M. S. Beasley
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, USA
| | - 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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27
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Chua YZ, Tylinski M, Tatsumi S, Ediger MD, Schick C. Glass transition and stable glass formation of tetrachloromethane. J Chem Phys 2016; 144:244503. [PMID: 27369523 DOI: 10.1063/1.4954665] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Physical vapor deposition (PVD) has been used to prepare organic glasses with very high kinetic stability and it has been suggested that molecular anisotropy is a prerequisite for stable glass formation. Here we use PVD to prepare glasses of tetrachloromethane, a simple organic molecule with a nearly isotropic molecular structure. In situ AC nanocalorimetry was used to characterize the vapor-deposited glasses. Glasses of high kinetic stability were produced by deposition near 0.8 Tg. The isothermal transformation of the vapor-deposited glasses into the supercooled liquid state gave further evidence that tetrachloromethane forms glasses with high kinetic stability, with the transformation time exceeding the structural relaxation time of the supercooled liquid by a factor of 10(3). The glass transition temperature of liquid-cooled tetrachloromethane is determined as Tg ≈ 78 K, which is different from previously reported values. The frequency dependence of the glass transition was also determined and the fragility was estimated as m ≈ 118. The successful formation of PVD glasses of tetrachloromethane which have high kinetic stability argues that molecular asymmetry is not a prerequisite for stable glass formation.
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Affiliation(s)
- Y Z Chua
- Institute of Physics, University of Rostock, Albert-Einstein-Str. 23-24, 18059 Rostock, Germany
| | - M Tylinski
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - S Tatsumi
- Department of Macromolecular Science and Engineering, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - M D Ediger
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - C Schick
- Institute of Physics, University of Rostock, Albert-Einstein-Str. 23-24, 18059 Rostock, Germany
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28
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Liu T, Cheng K, Salami-Ranjbaran E, Gao F, Li C, Tong X, Lin YC, Zhang Y, Zhang W, Klinge L, Walsh PJ, Fakhraai Z. The effect of chemical structure on the stability of physical vapor deposited glasses of 1,3,5-triarylbenzene. J Chem Phys 2016; 143:084506. [PMID: 26328855 DOI: 10.1063/1.4928521] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We detail the formation and properties associated with stable glasses (SG) formed by a series of structural analogues of 1,3-bis(1-naphthyl)-5-(2-naphthyl)benzene (α,α,β-TNB), a well-studied SG former. Five compounds with similar structural properties were synthesized and physical vapor-deposited with a constant deposition rate at various substrate temperatures (Tdep) in the range between 0.73 Tg and 0.96 Tg. These molecules include α,α,β-TNB, 3,5-di(naphthalen-1-yl)-1-phenylbenzene (α,α-P), 9-(3,5-di(naphthalen-1-yl)phenyl)anthracene (α,α-A), 9,9'-(5-(naphthalen-2-yl)-1,3-phenylene)dianthracene (β-AA), and 3,3',5,5'-tetra(naphthalen-1-yl)-1,1'-biphenyl (α,α,α,α-TNBP). Ellipsometry was used to study the transformations from the as-deposited glasses into ordinary glasses (OG). The stability of each film was evaluated by measuring the fictive temperature (Tf) and density difference between the as-deposited glass and OG. It is demonstrated that all five molecules can form SGs upon vapor deposition in this temperature range. In-depth studies on the dependence of the stability of as-deposited glasses upon Tdep were performed with three molecules, α,α,β-TNB, α,α-P, and α,α-A. The general trends of stability were comparable at the same Tdep/Tg for these three compounds. Similar to previous studies on α,α,β-TNB, vapor-deposited glasses of α,α-P and α,α-A formed the most stable structures around Tdep = 0.8-0.85 Tg. The most stable glass of each molecule showed the lowest thermal expansion coefficient compared to OG and a positive optical birefringence. However, the SGs of α,α-A were less stable compared to α,α-P and α,α,β-TNB at the relative Tdep/Tg. Based on Arrhenius extrapolation of the aging time, as a measure of stability, the most stable α,α-A glass was only aged for a few years as opposed to hundreds or thousands of years for other glasses. We hypothesize that the reduced stability is due to slower mobility at the free surface of α,α-A glass compared to the other two molecules.
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Affiliation(s)
- Tianyi Liu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Kevin Cheng
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Elmira Salami-Ranjbaran
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Feng Gao
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Chen Li
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Xiao Tong
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
| | - Yi-Chih Lin
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Yue Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - William Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Lindsey Klinge
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Patrick J Walsh
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Zahra Fakhraai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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29
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Madkou S, Melnichu I, Choukourov A, Krakovsky I, Biederman H, Schönhals A. In Situ Nanocalorimetric Investigations of Plasma Assisted Deposited Poly(ethylene oxide)-like Films by Specific Heat Spectroscopy. J Phys Chem B 2016; 120:3954-62. [PMID: 27055060 DOI: 10.1021/acs.jpcb.6b01355] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In recent years, highly cross-linked plasma polymers have started to unveil their potential in numerous biomedical applications in thin-film form. However, conventional diagnostic methods often fail due to their diverse molecular dynamics conformations. Here, glassy dynamics and the melting transition of thin PEO-like plasma assisted deposited (ppPEO) films (thickness 100 nm) were in situ studied by a combination of specific heat spectroscopy, utilizing a pJ/K sensitive ac-calorimeter chip, and composition analytical techniques. Different cross-linking densities were obtained by different plasma powers during the deposition of the films. Glassy dynamics were observed for all values of the plasma power. It was found that the glassy dynamics slows down with increasing the plasma power. Moreover, the underlying relaxation time spectra broaden indicating that the molecular motions become more heterogeneous with increasing plasma power. In a second set of the experiment, the melting behavior of the ppPEO films was studied. The melting temperature of ppPEO was found to decrease with increasing plasma power. This was explained by a decrease of the order in the crystals due to formation of chemical defects during the plasma process.
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Affiliation(s)
- Sherif Madkou
- Bundesanstalt für Materialforschung und -prüfung (BAM) , Unter den Eichen 87, 12205 Berlin, Germany
| | - Iurii Melnichu
- Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University in Prague , V Holesovickach 2, 18000 Prague 8, Czech Republic
| | - Andrei Choukourov
- Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University in Prague , V Holesovickach 2, 18000 Prague 8, Czech Republic
| | - Ivan Krakovsky
- Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University in Prague , V Holesovickach 2, 18000 Prague 8, Czech Republic
| | - Hynek Biederman
- Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University in Prague , V Holesovickach 2, 18000 Prague 8, Czech Republic
| | - Andreas Schönhals
- Bundesanstalt für Materialforschung und -prüfung (BAM) , Unter den Eichen 87, 12205 Berlin, Germany
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30
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Gómez J, Jiang J, Gujral A, Huang C, Yu L, Ediger MD. Vapor deposition of a smectic liquid crystal: highly anisotropic, homogeneous glasses with tunable molecular orientation. SOFT MATTER 2016; 12:2942-2947. [PMID: 26875700 DOI: 10.1039/c5sm02944a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Physical vapor deposition (PVD) has been used to prepare glasses of itraconazole, a smectic A liquid crystal. Glasses were deposited onto subtrates at a range of temperatures (Tsubstrate) near the glass transition temperature (Tg), with Tsubstrate/Tg ranging from 0.70 to 1.02. Infrared spectroscopy and spectroscopic ellipsometry were used to characterize the molecular orientation using the orientational order parameter, Sz, and the birefringence. We find that the molecules in glasses deposited at Tsubstrate = Tg are nearly perpendicular to the substrate (Sz = +0.66) while at lower Tsubstrate molecules are nearly parallel to the substrate (Sz = -0.45). The molecular orientation depends on the temperature of the substrate during preparation, allowing layered samples with differing orientations to be readily prepared. In addition, these vapor-deposited glasses are macroscopically homogeneous and molecularly flat. We interpret the combination of properties obtained for vapor-deposited glasses of itraconazole to result from a process where molecular orientation is determined by the structure and dynamics at the free surface of the glass during deposition. Vapor deposition of liquid crystals is likely a general approach for the preparation of highly anisotropic glasses with tunable molecular orientation for use in organic electronics and optoelectronics.
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Affiliation(s)
- Jaritza Gómez
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA.
| | - Jing Jiang
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Ankit Gujral
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA.
| | - Chengbin Huang
- School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, WI 53705-2222, USA
| | - Lian Yu
- School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, WI 53705-2222, USA
| | - M D Ediger
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA.
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31
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Kasina A, Putzeys T, Wübbenhorst M. Dielectric and specific heat relaxations in vapor deposited glycerol. J Chem Phys 2015; 143:244504. [PMID: 26723689 DOI: 10.1063/1.4937795] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Recently [S. Capponi, S. Napolitano, and M. Wübbenhorst, Nat. Commun. 3, 1233 (2012)], vapor deposited glasses of glycerol have been found to recover their super-cooled liquid state via a metastable, ordered liquid (MROL) state characterized by a tremendously enhanced dielectric strength along with a slow-down of the relaxation rate of the structural relaxation. To study the calorimetric signature of this phenomenon, we have implemented a chip-based, differential AC calorimeter in an organic molecular beam deposition setup, which allows the simultaneous measurement of dielectric relaxations via interdigitated comb electrodes and specific heat relaxation spectra during deposition and as function of the temperature. Heating of the as-deposited glass just above the bulk Tg and subsequent cooling/reheating revealed a step-wise increase in cp by in total 9%, indicating unambiguously that glycerol, through slow vapour deposition, forms a thermodynamically stable glass, which has a specific heat as low as that of crystalline glycerol. Moreover, these glasses were found to show excellent kinetic stability as well as evidenced by both a high onset-temperature and quasi-isothermal recovery measurements at -75 °C. The second goal of the study was to elucidate the impact of the MROL state on the specific heat and its relaxation to the super-cooled state. Conversion of "MROL glycerol" to its "normal" (ordinary liquid, OL) state revealed a second, small (∼2%) increase of the glassy cp, a little gain (<10%) in the relaxed specific heat, and no signs of deviations of τcal from that of normal "bulk" glycerol. These findings altogether suggest that the MROL state in glycerol comprises largely bulk-type glycerol that coexist with a minor volume fraction (<10%) of PVD-induced structural anomalies with a crystal-like calorimetric signature. Based on the new calorimetric findings, we have proposed a new physical picture that assumes the existence of rigid polar clusters (RPCs) and conclusively explains the extraordinary high kinetic stability of the MROL state, its specific calorimetric signature, the enhanced strength, and apparent slow-down of the dielectric α-relaxation. In this new picture, the incredibly slow and strengthened dielectric response is ascribed to driven rotational diffusion of whole RPCs, a mechanism that perfectly couples to the relaxation time of the "normal" glycerol fraction. First considerations based on the strength and the retardation of the dielectric RPCs' response yield independently a size estimate for the RPCs in the order of 4-5 nm. Finally, we have discussed possible crystallisation and reorganisation effects, which give rise to pronounced out-of phase components of the specific heat at higher temperatures.
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Affiliation(s)
- A Kasina
- Department of Physics and Astronomy, Soft Matter and Biophysics Section, KU Leuven, Leuven, Belgium
| | - T Putzeys
- Department of Physics and Astronomy, Soft Matter and Biophysics Section, KU Leuven, Leuven, Belgium
| | - M Wübbenhorst
- Department of Physics and Astronomy, Soft Matter and Biophysics Section, KU Leuven, Leuven, Belgium
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32
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Tylinski M, Sepúlveda A, Walters DM, Chua YZ, Schick C, Ediger MD. Vapor-deposited glasses of methyl-m-toluate: How uniform is stable glass transformation? J Chem Phys 2015; 143:244509. [PMID: 26723694 DOI: 10.1063/1.4938420] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
AC chip nanocalorimetry is used to characterize vapor-deposited glasses of methyl-m-toluate (MMT). Physical vapor deposition can prepare MMT glasses that have lower heat capacity and significantly higher kinetic stability compared to liquid-cooled glasses. When heated, highly stable MMT glasses transform into the supercooled liquid via propagating fronts. We present the first quantitative analysis of the temporal and spatial uniformities of these transformation fronts. The front velocity varies by less than 4% over the duration of the transformation. For films 280 nm thick, the transformation rates at different spatial positions in the film differ by about 25%; this quantity may be related to spatially heterogeneous dynamics in the stable glass. Our characterization of the kinetic stability of MMT stable glasses extends previous dielectric experiments and is in excellent agreement with these results.
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Affiliation(s)
- M Tylinski
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - A Sepúlveda
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Diane M Walters
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Y Z Chua
- Institute of Physics, University of Rostock, Wismarsche Str. 43-45, 18051 Rostock, Germany
| | - C Schick
- Institute of Physics, University of Rostock, Wismarsche Str. 43-45, 18051 Rostock, Germany
| | - M D Ediger
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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33
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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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34
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Smith RS, May RA, Kay BD. Probing Toluene and Ethylbenzene Stable Glass Formation Using Inert Gas Permeation. J Phys Chem Lett 2015; 6:3639-3644. [PMID: 26722735 DOI: 10.1021/acs.jpclett.5b01611] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Inert gas permeation is used to investigate the formation of stable glasses of toluene and ethylbenzene. The effect of deposition temperature (T(dep)) on the kinetic stability of the vapor deposited glasses is determined using Kr desorption spectra from within sandwich layers of either toluene or ethylbenzene. The results for toluene show that the most stable glass is formed at T(dep) = 0.92 T(g), although glasses with a kinetic stability within 50% of the most stable glass were found with deposition temperatures from 0.85 to 0.95 T(g). Similar results were found for ethylbenzene, which formed its most stable glass at 0.91 T(g) and formed stable glasses from 0.81 to 0.96 T(g). These results are consistent with recent calorimetric studies and demonstrate that the inert gas permeation technique provides a direct method to observe the onset of molecular translation motion that accompanies the glass to supercooled liquid transition.
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Affiliation(s)
- R Scott Smith
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - R Alan May
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - Bruce D Kay
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
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35
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Whitaker KR, Tylinski M, Ahrenberg M, Schick C, Ediger MD. Kinetic stability and heat capacity of vapor-deposited glasses of o-terphenyl. J Chem Phys 2015; 143:084511. [DOI: 10.1063/1.4929511] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Katherine R. Whitaker
- Department of Mathematics and Physical Sciences, Louisiana State University of Alexandria, Alexandria, Louisiana 71302, USA
| | - M. Tylinski
- Department of Chemistry, University of Wisconsin – Madison, Madison, Wisconsin 53706, USA
| | | | - Christoph Schick
- Institute of Physics, University of Rostock, Rostock 18051, Germany
| | - M. D. Ediger
- Department of Chemistry, University of Wisconsin – Madison, Madison, Wisconsin 53706, USA
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36
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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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37
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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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38
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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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39
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Tunable molecular orientation and elevated thermal stability of vapor-deposited organic semiconductors. Proc Natl Acad Sci U S A 2015; 112:4227-32. [PMID: 25831545 DOI: 10.1073/pnas.1421042112] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Physical vapor deposition is commonly used to prepare organic glasses that serve as the active layers in light-emitting diodes, photovoltaics, and other devices. Recent work has shown that orienting the molecules in such organic semiconductors can significantly enhance device performance. We apply a high-throughput characterization scheme to investigate the effect of the substrate temperature (Tsubstrate) on glasses of three organic molecules used as semiconductors. The optical and material properties are evaluated with spectroscopic ellipsometry. We find that molecular orientation in these glasses is continuously tunable and controlled by Tsubstrate/Tg, where Tg is the glass transition temperature. All three molecules can produce highly anisotropic glasses; the dependence of molecular orientation upon substrate temperature is remarkably similar and nearly independent of molecular length. All three compounds form "stable glasses" with high density and thermal stability, and have properties similar to stable glasses prepared from model glass formers. Simulations reproduce the experimental trends and explain molecular orientation in the deposited glasses in terms of the surface properties of the equilibrium liquid. By showing that organic semiconductors form stable glasses, these results provide an avenue for systematic performance optimization of active layers in organic electronics.
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40
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L. M. Ramos SL, Chigira AK, Oguni M. Devitrification Properties of Vapor-Deposited Ethylcyclohexane Glasses and Interpretation of the Molecular Mechanism for Formation of Vapor-Deposited Glasses. J Phys Chem B 2015; 119:4076-83. [DOI: 10.1021/jp5109174] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Sergio Luis L. M. Ramos
- Department of Chemistry, Graduate School
of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Atsuko. K. Chigira
- Department of Chemistry, Graduate School
of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Masaharu Oguni
- Department of Chemistry, Graduate School
of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
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41
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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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42
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Sepúlveda A, Tylinski M, Guiseppi-Elie A, Richert R, Ediger MD. Role of fragility in the formation of highly stable organic glasses. PHYSICAL REVIEW LETTERS 2014; 113:045901. [PMID: 25105633 DOI: 10.1103/physrevlett.113.045901] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Indexed: 06/03/2023]
Abstract
In situ dielectric spectroscopy has been used to characterize vapor-deposited glasses of methyl-m-toluate (MMT), an organic glass former with low fragility (m = 60). Deposition near 0.84T(g) produces glasses of very high kinetic stability; these materials are comparable in stability to the most stable glasses produced from more fragile glass formers. Highly stable glasses of MMT, when annealed above T(g), transform into the supercooled liquid by a heterogeneous mechanism. A constant velocity propagating front is initiated at the free surface and controls the transformation of thin films. The transition to a bulk-dominated transformation process occurs at 5 μm, the largest length scale reported for any glass. Contrary to recent conclusions, we find that physical vapor deposition can form highly stable organic glasses across the entire range of liquid fragilities.
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Affiliation(s)
- A Sepúlveda
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M Tylinski
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - A Guiseppi-Elie
- Department of Bioengineering, Clemson University, Clemson, South Carolina 29634, USA
| | - R 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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43
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Chua YZ, Schulz G, Shoifet E, Huth H, Zorn R, Scmelzer JWP, Schick C. Glass transition cooperativity from broad band heat capacity spectroscopy. Colloid Polym Sci 2014. [DOI: 10.1007/s00396-014-3280-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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44
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Ishii K, Nakayama H. Structural relaxation of vapor-deposited molecular glasses and supercooled liquids. Phys Chem Chem Phys 2014; 16:12073-92. [DOI: 10.1039/c4cp00458b] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The properties of vapor-deposited molecular glasses largely depend on deposition conditions, and stable and/or dense glasses are formed with several compounds.
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Affiliation(s)
- Kikujiro Ishii
- Department of Chemistry
- Gakushuin University
- Tokyo 171-8588, Japan
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45
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Nakayama H, Omori K, Ino-u-e K, Ishii K. Molar Volumes of Ethylcyclohexane and Butyronitrile Glasses Resulting from Vapor Deposition: Dependence on Deposition Temperature and Comparison to Alkylbenzenes. J Phys Chem B 2013; 117:10311-9. [DOI: 10.1021/jp404256r] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Hideyuki Nakayama
- Department
of Chemistry, Gakushuin University, 1-5-1
Mejiro, Toshimaku, Tokyo 171-8588, Japan
| | - Kio Omori
- Department
of Chemistry, Gakushuin University, 1-5-1
Mejiro, Toshimaku, Tokyo 171-8588, Japan
| | - Katsunobu Ino-u-e
- Department
of Chemistry, Gakushuin University, 1-5-1
Mejiro, Toshimaku, Tokyo 171-8588, Japan
| | - Kikujiro Ishii
- Department
of Chemistry, Gakushuin University, 1-5-1
Mejiro, Toshimaku, Tokyo 171-8588, Japan
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46
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Whitaker KR, Scifo DJ, Ediger MD, Ahrenberg M, Schick C. Highly Stable Glasses of cis-Decalin and cis/trans-Decalin Mixtures. J Phys Chem B 2013; 117:12724-33. [DOI: 10.1021/jp400960g] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Katherine R. Whitaker
- Department
of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin
53706, United States
| | - Daniel J. Scifo
- 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
| | | | - Christoph Schick
- Institute
of Physics, University of Rostock, Rostock
18051, Germany
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