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Luo M, Chen A, Huang C, Guo M, Cai T. Effects of Polymers on Cocrystal Growth in a Drug-Drug Coamorphous System: Relations between Glass-to-Crystal Growth and Surface-Enhanced Crystal Growth. Mol Pharm 2024; 21:3591-3602. [PMID: 38818946 DOI: 10.1021/acs.molpharmaceut.4c00315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
Coamorphous and cocrystal drug delivery systems provide attractive crystal engineering strategies for improving the solubilities, dissolution rates, and oral bioavailabilities of poorly water-soluble drugs. Polymeric additives have often been used to inhibit the unwanted crystallization of amorphous drugs. However, the transformation of a coamorphous phase to a cocrystal phase in the presence of polymers has not been fully elucidated. Herein, we investigated the effects of low concentrations of the polymeric excipients poly(ethylene oxide) (PEO) and poly(vinylpyrrolidone) (PVP) on the growth of carbamazepine-celecoxib (CBZ-CEL) cocrystals from the corresponding coamorphous phase. PEO accelerated the growth rate of the cocrystals by increasing the molecular mobility of the coamorphous system, while PVP had the opposite effect. The coamorphous CBZ-CEL system exhibited two anomalously fast crystal growth modes: glass-to-crystal (GC) growth in the bulk and accelerated crystal growth at the free surface. These two fast growth modes both disappeared after doping with PEO (1-3% w/w) but were retained in the presence of PVP, indicating a potential correlation between the two fast crystal growth modes. We propose that the different effects of PEO and PVP on the crystal growth modes arose from weaker effects of the polymers on cocrystallization at the surface than in the bulk. This work provides a deep understanding of the mechanisms by which polymers influence the cocrystallization kinetics of a multicomponent amorphous phase and highlights the importance of polymer selection in stabilizing coamorphous systems or preparing cocrystals via solid-based methods.
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Affiliation(s)
- Minqian Luo
- Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - An Chen
- Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Chengbin Huang
- CMC Drug Product, Research and Development, BeiGene Co., Inc., Beijing 102206, China
| | - Minshan Guo
- Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Ting Cai
- Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Department of Pharmaceutical Engineering, School of Engineering, China Pharmaceutical University, Nanjing 211198, China
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2
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Niyonkuru P, Bennett RA, Zachman MJ, Zimmerman JD. Effect of molecular permanent dipole moment on guest aggregation and exciton quenching in phosphorescent organic light emitting diodes. J Chem Phys 2024; 160:244304. [PMID: 38912679 DOI: 10.1063/5.0201560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 05/27/2024] [Indexed: 06/25/2024] Open
Abstract
This study explores the effect of molecular permanent dipole moment (PDM) on aggregation of guest molecules in phosphorescent host-guest organic light-emitting diodes (OLEDs). Through a combination of photoluminescence measurements, high-angle annular dark-field scanning transmission electron microscopy analysis, and an Ising model based physical vapor-deposition simulation, we show that higher PDM of tris[2-phenylpyridinato-C2,N]iridium(III) guest can actually lead to a reduced aggregation relative to tris[bis[2-(2-pyridinyl-N)phenyl-C] (acetylacetonato)iridium(III) when doped into a non-polar host 1,3,5-tris(carbazol-9-yl)benzene. This study further explores the effect of host polarity by using a polar host 3',5'-di(carbazol-9-yl)-[1,1'-biphenyl]-3,5-dicarbonitrile, and it is shown that the polar host leads to reduced guest aggregation. This study provides a comprehensive understanding of the impact of molecular PDM on OLED material efficiency and stability, providing insights for optimizing phosphorescent OLED materials.
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Affiliation(s)
- Paul Niyonkuru
- Department of Physics, Colorado School of Mines, Golden, Colorado 80401, USA
| | - Roland A Bennett
- Department of Physics, Colorado School of Mines, Golden, Colorado 80401, USA
| | - Michael J Zachman
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Jeramy D Zimmerman
- Department of Physics, Colorado School of Mines, Golden, Colorado 80401, USA
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3
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Li Y, Bishop C, Cui K, Schmidt JR, Ediger MD, Yu L. Surface diffusion of a glassy discotic organic semiconductor and the surface mobility gradient of molecular glasses. J Chem Phys 2022; 156:094710. [PMID: 35259874 DOI: 10.1063/5.0079890] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Surface diffusion has been measured in the glass of an organic semiconductor, MTDATA, using the method of surface grating decay. The decay rate was measured as a function of temperature and grating wavelength, and the results indicate that the decay mechanism is viscous flow at high temperatures and surface diffusion at low temperatures. Surface diffusion in MTDATA is enhanced by 4 orders of magnitude relative to bulk diffusion when compared at the glass transition temperature Tg. The result on MTDATA has been analyzed along with the results on other molecular glasses without extensive hydrogen bonds. In total, these systems cover a wide range of molecular geometries from rod-like to quasi-spherical to discotic and their surface diffusion coefficients vary by 9 orders of magnitude. We find that the variation is well explained by the existence of a steep surface mobility gradient and the anchoring of surface molecules at different depths. Quantitative analysis of these results supports a recently proposed double-exponential form for the mobility gradient: log D(T, z) = log Dv(T) + [log D0 - log Dv(T)]exp(-z/ξ), where D(T, z) is the depth-dependent diffusion coefficient, Dv(T) is the bulk diffusion coefficient, D0 ≈ 10-8 m2/s, and ξ ≈ 1.5 nm. Assuming representative bulk diffusion coefficients for these fragile glass formers, the model reproduces the presently known surface diffusion rates within 0.6 decade. Our result provides a general way to predict the surface diffusion rates in molecular glasses.
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Affiliation(s)
- Yuhui Li
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
| | - Camille Bishop
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Kai Cui
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - J R Schmidt
- 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
| | - Lian Yu
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
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4
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Li Y, Annamareddy A, Morgan D, Yu Z, Wang B, Cao C, Perepezko JH, Ediger MD, Voyles PM, Yu L. Surface Diffusion Is Controlled by Bulk Fragility across All Glass Types. PHYSICAL REVIEW LETTERS 2022; 128:075501. [PMID: 35244425 DOI: 10.1103/physrevlett.128.075501] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
Surface diffusion is vastly faster than bulk diffusion in some glasses, but only moderately enhanced in others. We show that this variation is closely linked to bulk fragility, a common measure of how quickly dynamics is excited when a glass is heated to become a liquid. In fragile molecular glasses, surface diffusion can be a factor of 10^{8} faster than bulk diffusion at the glass transition temperature, while in the strong system SiO_{2}, the enhancement is a factor of 10. Between these two extremes lie systems of intermediate fragility, including metallic glasses and amorphous selenium and silicon. This indicates that stronger liquids have greater resistance to dynamic excitation from bulk to surface and enables prediction of surface diffusion, surface crystallization, and formation of stable glasses by vapor deposition.
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Affiliation(s)
- Yuhui Li
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
| | - Ajay Annamareddy
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Dane Morgan
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Zheng Yu
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Bu Wang
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Chengrong Cao
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - John H Perepezko
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M D Ediger
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Paul M Voyles
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Lian Yu
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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5
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Bishop C, Chen Z, Toney MF, Bock H, Yu L, Ediger MD. Using Deposition Rate and Substrate Temperature to Manipulate Liquid Crystal-Like Order in a Vapor-Deposited Hexagonal Columnar Glass. J Phys Chem B 2021; 125:2761-2770. [PMID: 33683124 DOI: 10.1021/acs.jpcb.0c11564] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigate vapor-deposited glasses of a phenanthroperylene ester, known to form an equilibrium hexagonal columnar phase, and show that liquid crystal-like order can be manipulated by the choice of deposition rate and substrate temperature during deposition. We find that rate-temperature superposition (RTS)-the equivalence of lowering the deposition rate and increasing the substrate temperature-can be used to predict and control the molecular orientation in vapor-deposited glasses over a wide range of substrate temperatures (0.75-1.0 Tg). This work extends RTS to a new structural motif, hexagonal columnar liquid crystal order, which is being explored for organic electronic applications. By several metrics, including the apparent average face-to-face nearest-neighbor distance, physical vapor deposition (PVD) glasses of the phenanthroperylene ester are as ordered as the glass prepared by cooling the equilibrium liquid crystal. By other measures, the PVD glasses are less ordered than the cooled liquid crystal. We explain the difference in the maximum attainable order with the existence of a gradient in molecular mobility at the free surface of a liquid crystal and its impact upon different mechanisms of structural rearrangement. This free surface equilibration mechanism explains the success of the RTS principle and provides guidance regarding the types of order most readily enhanced by vapor deposition. This work extends the applicability of RTS to include molecular systems with a diverse range of higher-order liquid-crystalline morphologies that could be useful for new organic electronic applications.
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Affiliation(s)
- Camille Bishop
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, Wisconsin 53706, United States
| | - Zhenxuan Chen
- School of Pharmacy, University of Wisconsin-Madison, 777 Highland Ave, Madison, Wisconsin 53705, United States
| | - Michael F Toney
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Harald Bock
- Centre de Recherche Paul Pascal, CNRS & Université de Bordeaux, 115, av. Schweitzer, 33600 Pessac, France
| | - Lian Yu
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, Wisconsin 53706, United States.,School of Pharmacy, University of Wisconsin-Madison, 777 Highland Ave, Madison, Wisconsin 53705, United States
| | - M D Ediger
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, Wisconsin 53706, United States
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6
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Barták J, Málek J, Bagchi K, Ediger MD, Li Y, Yu L. Surface mobility in amorphous selenium and comparison with organic molecular glasses. J Chem Phys 2021; 154:074703. [DOI: 10.1063/5.0041273] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jaroslav Barták
- Department of Physical Chemistry, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic
| | - Jirí Málek
- Department of Physical Chemistry, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic
| | - Kushal Bagchi
- 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
| | - Yuhui Li
- School of Pharmacy, University of Wisconsin–Madison, Madison, Wisconsin 53705, USA
| | - Lian Yu
- School of Pharmacy, University of Wisconsin–Madison, Madison, Wisconsin 53705, USA
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7
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Li Y, Zhang W, Bishop C, Huang C, Ediger MD, Yu L. Surface diffusion in glasses of rod-like molecules posaconazole and itraconazole: effect of interfacial molecular alignment and bulk penetration. SOFT MATTER 2020; 16:5062-5070. [PMID: 32453335 DOI: 10.1039/d0sm00353k] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The method of surface grating decay has been used to measure surface diffusion in the glasses of two rod-like molecules posaconazole (POS) and itraconazole (ITZ). Although structurally similar antifungal medicines, ITZ forms liquid-crystalline phases while POS does not. Surface diffusion in these systems is significantly slower than in the glasses of quasi-spherical molecules of similar volume when compared at the glass transition temperature Tg. Between the two systems, ITZ has slower surface diffusion. These results are explained on the basis of the near-vertical orientation of the rod-like molecules at the surface and their deep penetration into the bulk where mobility is low. For molecular glasses without extensive hydrogen bonds, we find that the surface diffusion coefficient at Tg decreases smoothly with the penetration depth of surface molecules and the trend has the double-exponential form for the surface mobility gradient observed in simulations. This supports the view that these molecular glasses have a similar mobility vs. depth profile and their different surface diffusion rates arise simply from the different depths at which molecules are anchored. Our results also provide support for a previously observed correlation between the rate of surface diffusion and the fragility of the bulk liquid.
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Affiliation(s)
- Yuhui Li
- School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA.
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8
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Bannow J, Karl M, Larsen PE, Hwu ET, Rades T. Direct Measurement of Lateral Molecular Diffusivity on the Surface of Supersaturated Amorphous Solid Dispersions by Atomic Force Microscopy. Mol Pharm 2020; 17:1715-1722. [PMID: 32207959 DOI: 10.1021/acs.molpharmaceut.0c00176] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Quantifying molecular surface diffusivity is of broad interest in many different fields of science and technology. In this study, the method of surface grating decay is utilized to investigate the surface diffusion of practical relevant amorphous solid dispersions of indomethacin and the polymeric excipient Soluplus (a polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer) at various polymer concentrations (1-20% w/w). The study confirms that measuring surface diffusivity below the system's glass transition temperature is possible with a simplified atomic force microscopy setup. Results highlight a striking polymer influence on the surface diffusivity of drug molecules at low polymer concentrations and a turnover point to a polymer dominated diffusion at around three percent (w/w) polymer concentration. The surface diffusion measurements further correlate well with the observed increase in physical stability of the system as measured by X-ray powder diffraction. These findings are of vital interest in both the applied use and fundamental understanding of amorphous solid dispersions.
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Affiliation(s)
- Jacob Bannow
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 København Ø, Denmark
| | - Maximilian Karl
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 København Ø, Denmark
| | - Peter Emil Larsen
- Department of Health Technology, Technical University of Denmark, Ørsteds Plads 345C, 2800 Kongens Lyngby, Denmark
| | - En Te Hwu
- Department of Health Technology, Technical University of Denmark, Ørsteds Plads 345C, 2800 Kongens Lyngby, Denmark
| | - Thomas Rades
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 København Ø, Denmark
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9
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Samanta S, Huang G, Gao G, Zhang Y, Zhang A, Wolf S, Woods CN, Jin Y, Walsh PJ, Fakhraai Z. Exploring the Importance of Surface Diffusion in Stability of Vapor-Deposited Organic Glasses. J Phys Chem B 2019; 123:4108-4117. [PMID: 30998844 DOI: 10.1021/acs.jpcb.9b01012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Stable glasses are formed during physical vapor deposition (PVD), through the surface-mediated equilibration process. Understanding surface relaxation dynamics is important in understanding the details of this process. Direct measurements of the surface relaxation times in molecular glass systems are challenging. As such, surface diffusion measurements have been used in the past as a proxy for the surface relaxation process. In this study, we show that the absence of enhanced surface diffusion is not a reliable predictor of reduced ability to produce stable glasses. To demonstrate, we have prepared stable glasses (SGs) from two structurally similar organic molecules, 1,3-bis(1-naphthyl)-5-(2-naphthyl)benzene (TNB) and 9-(3,5-di(naphthalen-1-yl)phenyl)anthracene (α,α-A), with similar density increase and improved kinetic stability as compared to their liquid-quenched (LQ) counterparts. The surface diffusion values of these glasses were measured both in the LQ and SG states below their glass transition temperatures ( Tgs) using gold nanorod probes. While TNB shows enhanced surface diffusion in both SG and LQ states, no significant surface Tg diffusion is observed on the surface of α,α-A within our experimental time scales. However, isothermal dewetting experiments on ultrathin films of both molecules below Tg indicate the existence of enhanced dynamics in ultrathin films for both molecules, indirectly showing the existence of an enhanced mobile surface layer. Both films produce stable glasses, which is another indication for the existence of the mobile surface layer. Our results suggest that lateral surface diffusion may not be a good proxy for enhanced surface relaxation dynamics required to produce stable glasses, and thus, other types of measurements to directly probe the surface relaxation times may be necessary.
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Affiliation(s)
- Subarna Samanta
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Georgia Huang
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Gui Gao
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Yue Zhang
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Aixi Zhang
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Sarah Wolf
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Connor N Woods
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Yi Jin
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Patrick J Walsh
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Zahra Fakhraai
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
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10
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Abstract
The term "organic solids" encompasses both crystals and glasses. Organic crystals are commonly grown for purification and structure determination and are being extensively explored for applications in organic electronics including field effect transistors. The ability to control the packing of one molecule relative to its neighbors is of critical importance for most uses of organic crystals. Often, anisotropic packing is also highly desirable as it enhances charge transport and optimizes light absorption/emission. When compared to crystals, the local packing in organic glasses is highly disordered and often isotropic. Glasses, however, offer two key advantages with respect to crystals. First, glasses typically lack grain boundaries and thus exhibit better macroscopic homogeneity. Second, glass composition can often be varied over a wide range while maintaining homogeneity. Besides electronic materials, many modern plastics used in a wide range of technologies are organic glasses, and the glassy state is being increasingly utilized to deliver pharmaceuticals because of higher bioavailability. In this article, we introduce vapor-deposited organic glasses as hybrid materials that combine some of the useful features of crystals and traditional liquid-cooled glasses. Physical vapor deposition produces glasses by directly condensing molecules from the gas phase onto a temperature-controlled substrate and allows film thickness to be controlled with nanometer precision. Just as liquid-cooled glasses, vapor-deposited glasses have smooth surfaces and lack grain boundaries. These attributes are critical for applications such as organic light emitting diodes (OLEDs), in which vapor-deposited glasses of organic semiconductors form the active layers. In common with crystals, vapor-deposited glasses can exhibit anisotropic packing, and the extent of anisotropy can be comparable to that of the typical organic crystal. For vapor-deposited glasses, in contrast to crystals, anisotropic packing can generally be controlled as a continuous variable. Deposition conditions can be chosen to produce glasses with significant molecular orientation (molecules "standing up" or "lying down" relative to the substrate), and π-stacking can be directed along different directions relative to the substrate. Over the last five years, we have gained a fundamental understanding of the mechanism that controls the anisotropy of vapor-deposited glasses and learned how to control many aspects of anisotropic packing. Two key elements that enable such control are the high mobility present at the surface of an organic glass and the tendency of the surface to promote anisotropic packing of molecules. In contrast to traditional epitaxial growth, for vapor-deposited glasses, the free surface (not the substrate) acts as a template that controls the structure of a growing film. The structure of any given layer is decoupled from those beneath it, thereby providing considerable freedom in producing layered glassy structures.
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Affiliation(s)
- M. D. Ediger
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Juan de Pablo
- Institute of Molecular Engineering, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, United States
| | - Lian Yu
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
- School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, Wisconsin 53705, United States
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11
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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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12
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Chen Y, Chen Z, Tylinski M, Ediger MD, Yu L. Effect of molecular size and hydrogen bonding on three surface-facilitated processes in molecular glasses: Surface diffusion, surface crystal growth, and formation of stable glasses by vapor deposition. J Chem Phys 2019; 150:024502. [DOI: 10.1063/1.5079441] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yinshan Chen
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
| | - Zhenxuan Chen
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
| | - Michael 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
| | - Lian Yu
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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13
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Qiu Y, Antony LW, Torkelson JM, de Pablo JJ, Ediger MD. Tenfold increase in the photostability of an azobenzene guest in vapor-deposited glass mixtures. J Chem Phys 2018; 149:204503. [PMID: 30501262 DOI: 10.1063/1.5052003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Improvements to the photostability of organic glasses for use in electronic applications have generally relied on the modification of the chemical structure. We show here that the photostability of a guest molecule can also be significantly improved-without chemical modification-by using physical vapor deposition to pack molecules more densely. Photoisomerization of the substituted azobenzene, 4,4'-diphenyl azobenzene, was studied in a vapor-deposited glass matrix of celecoxib. We directly measure photoisomerization of trans- to cis-states via Ultraviolet-visible (UV-Vis) spectroscopy and show that the rate of photoisomerization depends upon the substrate temperature used during co-deposition of the glass. Photostability correlates reasonably with the density of the glass, where the optimum glass is about tenfold more photostable than the liquid-cooled glass. Molecular simulations, which mimic photoisomerization, also demonstrate that photoreaction of a guest molecule can be suppressed in vapor-deposited glasses. From the simulations, we estimate that the region that is disrupted by a single photoisomerization event encompasses approximately 5 molecules.
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Affiliation(s)
- Yue Qiu
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Lucas W Antony
- Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - John M Torkelson
- Department of Chemical and Biological Engineering and Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Juan J de Pablo
- Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - M D Ediger
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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14
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Luo S, Kui X, Xing E, Wang X, Xue G, Schick C, Hu W, Zhuravlev E, Zhou D. Interplay between Free Surface and Solid Interface Nucleation on Two-Step Crystallization of Poly(ethylene terephthalate) Thin Films Studied by Fast Scanning Calorimetry. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00692] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Shaochuan Luo
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, and The State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China
| | - Xing Kui
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, and The State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China
| | - Enran Xing
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, and The State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China
| | - Xiaoliang Wang
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, and The State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China
| | - Gi Xue
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, and The State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China
| | - Christoph Schick
- Institute of Physics, University of Rostock, Wismarsche Str. 43-45, 18051 Rostock, Germany
| | - Wenbing Hu
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, and The State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China
| | - Evgeny Zhuravlev
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, and The State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China
- Institute of Physics, University of Rostock, Wismarsche Str. 43-45, 18051 Rostock, Germany
- Shenzhen Research Institute, Nanjing University, Shenzhen 518057, P. R. China
| | - Dongshan Zhou
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, and The State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China
- School of Physical Science and Technology, Xinjiang Key Laboratory and Phase Transitions and Microstructures in Condensed Matters, Yili Normal University, Yining 835000, P. R. China
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15
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Huang C, Ruan S, Cai T, Yu L. Fast Surface Diffusion and Crystallization of Amorphous Griseofulvin. J Phys Chem B 2017; 121:9463-9468. [DOI: 10.1021/acs.jpcb.7b07319] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Chengbin Huang
- School
of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Shigang Ruan
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Ting Cai
- State
Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug
Discovery for Metabolic Diseases, Department of Pharmaceutics, College
of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Lian Yu
- School
of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
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16
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Chen Y, Zhu M, Laventure A, Lebel O, Ediger MD, Yu L. Influence of Hydrogen Bonding on the Surface Diffusion of Molecular Glasses: Comparison of Three Triazines. J Phys Chem B 2017. [PMID: 28651429 DOI: 10.1021/acs.jpcb.7b05333] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Surface grating decay measurements have been performed on three closely related molecular glasses to study the effect of intermolecular hydrogen bonds on surface diffusion. The three molecules are derivatives of bis(3,5-dimethyl-phenylamino)-1,3,5-triazine and differ only in the functional group R at the 2-position, with R being C2H5, OCH3, and NHCH3, and referred to as "Et", "OMe", and "NHMe", respectively. Of the three molecules, NHMe forms more extensive intermolecular hydrogen bonds than Et and OMe and was found to have slower surface diffusion. For Et and OMe, surface diffusion is so fast that it replaces viscous flow as the mechanism of surface grating decay as temperature is lowered. In contrast, no such transition was observed for NHMe under the same conditions, indicating significantly slower surface diffusion. This result is consistent with the previous finding that extensive intermolecular hydrogen bonds slow down surface diffusion in molecular glasses and is attributed to the persistence of hydrogen bonds even in the surface environment. This result is also consistent with the lower stability of the vapor-deposited glass of NHMe relative to those of Et and OMe and supports the view that surface mobility controls the stability of vapor-deposited glasses.
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Affiliation(s)
- Yinshan Chen
- School of Pharmacy, University of Wisconsin-Madison , Madison, Wisconsin 53705, United States
| | - Men Zhu
- Department of Chemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Audrey Laventure
- Department of Chemistry and Chemical Engineering, Royal Military College of Canada , Kingston, Ontario K7K 7B4, Canada
| | - Olivier Lebel
- Department of Chemistry and Chemical Engineering, Royal Military College of Canada , Kingston, Ontario K7K 7B4, Canada
| | - M D Ediger
- Department of Chemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Lian Yu
- School of Pharmacy, University of Wisconsin-Madison , Madison, Wisconsin 53705, United States.,Department of Chemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
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17
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Ruan S, Musumeci D, Zhang W, Gujral A, Ediger MD, Yu L. Surface transport mechanisms in molecular glasses probed by the exposure of nano-particles. J Chem Phys 2017; 146:203324. [DOI: 10.1063/1.4978667] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Shigang Ruan
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin 53705, USA
| | - Daniele Musumeci
- School of Pharmacy, University of Wisconsin–Madison, Madison, Wisconsin 53705, USA
| | - Wei Zhang
- School of Pharmacy, University of Wisconsin–Madison, Madison, Wisconsin 53705, USA
| | - Ankit Gujral
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin 53705, USA
| | - M. D. Ediger
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin 53705, USA
| | - Lian Yu
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin 53705, USA
- School of Pharmacy, University of Wisconsin–Madison, Madison, Wisconsin 53705, USA
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18
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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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19
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Zhang Y, Fakhraai Z. Decoupling of surface diffusion and relaxation dynamics of molecular glasses. Proc Natl Acad Sci U S A 2017; 114:4915-4919. [PMID: 28373544 PMCID: PMC5441703 DOI: 10.1073/pnas.1701400114] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tobacco mosaic virus is used as a probe to measure surface diffusion of ultrathin films of N,N'-Bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD) (12 nm [Formula: see text] 53 nm, where [Formula: see text] is the film thickness) at various temperatures below the glass transition temperature, [Formula: see text], of all films. As the film thickness is decreased, [Formula: see text] decreases rapidly and the average film dynamics are enhanced by 6-14 orders of magnitude. We show that the surface diffusion is invariant of the film thickness decrease and the resulting enhanced overall mobility. The values of the surface diffusion coefficient and its temperature dependence are invariant of film thickness and are the same as the corresponding bulk values ([Formula: see text]400 nm). For the thinnest films ([Formula: see text]20 nm), the effective activation energy for rearrangement (temperature dependence of relaxation times) becomes smaller than the activation energy for surface diffusion. These results suggest that the fast surface diffusion is decoupled from film relaxation dynamics and is a solely free surface property.
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Affiliation(s)
- Yue Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323
| | - Zahra Fakhraai
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323
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20
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Zhang Y, Fakhraai Z. Invariant Fast Diffusion on the Surfaces of Ultrastable and Aged Molecular Glasses. PHYSICAL REVIEW LETTERS 2017; 118:066101. [PMID: 28234512 DOI: 10.1103/physrevlett.118.066101] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Indexed: 06/06/2023]
Abstract
Surface diffusion of molecular glasses is found to be orders of magnitude faster than bulk diffusion, with a stronger dependence on the molecular size and intermolecular interactions. In this study, we investigate the effect of variations in bulk dynamics on the surface diffusion of molecular glasses. Using the tobacco mosaic virus as a probe particle, we measure the surface diffusion on glasses of the same composition but with orders of magnitude of variations in bulk relaxation dynamics, produced by physical vapor deposition, physical aging, and liquid quenching. The bulk fictive temperatures of these glasses span over 35 K, indicating 13 to 20 orders of magnitude changes in bulk relaxation times. However, the surface diffusion coefficients on these glasses are measured to be identical at two temperatures below the bulk glass transition temperature T_{g}. These results suggest that surface diffusion has no dependence on the bulk relaxation dynamics when measured below T_{g}.
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Affiliation(s)
- Yue Zhang
- 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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21
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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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22
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Zhang Y, Potter R, Zhang W, Fakhraai Z. Using tobacco mosaic virus to probe enhanced surface diffusion of molecular glasses. SOFT MATTER 2016; 12:9115-9120. [PMID: 27759140 DOI: 10.1039/c6sm01566b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Recent studies have shown that diffusion on the surface of organic glasses can be many orders of magnitude faster than bulk diffusion. Developing new probes that can readily measure surface diffusion can help study the effect of parameters such as chemical structure, intermolecular interaction, molecules' shape and size on the enhanced surface diffusion. In this study, we develop a novel probe that significantly simplifies these types of studies. Tobacco mosaic virus (TMV) is used as probe particle to measure surface diffusion coefficient of molecular glass N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD). The evolution of the meniscus formed around TMV is probed as a function of time at various temperatures. TMV has a well-defined, mono-dispersed, cylindrical shape, with a large aspect-ratio (average diameter of 16.6 nm, length of 300 nm). As such, the shape of the meniscus around the center of TMV is semi-two dimensional, which compared to using a nanosphere as probe, increases the driving force for meniscus formation and simplifies the analysis of surface diffusion. We show that under these conditions, after a short transient time the shape of the meniscus is self-similar, allowing accurate determination of the surface diffusion coefficient. Measurements at various temperatures are then performed to investigate the temperature dependence of the surface diffusion coefficient. It is found that surface diffusion is greatly enhanced in TPD and has a lower activation barrier compared to the bulk counterpart. These observations are consistent with previous studies of surface diffusion on molecular glasses, demonstrating the accuracy of this method.
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Affiliation(s)
- Yue Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
| | - Richard Potter
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
| | - William Zhang
- 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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23
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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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24
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Zhang Y, Glor EC, Li M, Liu T, Wahid K, Zhang W, Riggleman RA, Fakhraai Z. Long-range correlated dynamics in ultra-thin molecular glass films. J Chem Phys 2016. [DOI: 10.1063/1.4962734] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yue Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Ethan C. Glor
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Mu Li
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6272, USA
| | - Tianyi Liu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Kareem Wahid
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - William Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Robert A. Riggleman
- Department of Chemical and Bimolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6315, USA
| | - Zahra Fakhraai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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25
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Chen Y, Zhang W, Yu L. Hydrogen Bonding Slows Down Surface Diffusion of Molecular Glasses. J Phys Chem B 2016; 120:8007-15. [DOI: 10.1021/acs.jpcb.6b05658] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Yinshan Chen
- School of Pharmacy and ‡Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53705, United States
| | - Wei Zhang
- School of Pharmacy and ‡Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53705, United States
| | - Lian Yu
- School of Pharmacy and ‡Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53705, United States
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