1
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Xiao Y, Bai P, Zhang Z, Guo Y. Direct measurement and modeling of viscoelastic-viscoplastic properties of freely standing thin polystyrene films. J Chem Phys 2023; 159:214903. [PMID: 38054519 DOI: 10.1063/5.0176115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 11/12/2023] [Indexed: 12/07/2023] Open
Abstract
The demand for applications, such as coatings, separation filters, and electronic packaging, has greatly driven the research of polymer films. At nanometer scale, mechanical properties of thin polymer films can significantly deviate from bulk. Despite outstanding progresses, there still lack deep discussions on nonlinear viscoelastic-viscoplastic response and their interactions under nanoconfinement. In this work, by conducting measurements via the bubble inflation method and modelling using Schapery and Perzyna equations, we demonstrate nonlinear viscoelastic-viscoplastic properties of freely standing thin polystyrene (PS) films. The results show the unchanged glassy compliance and the rubbery stiffening phenomenon for thin PS films, where the lower rubbery plateau in rubbery stiffening may originate from the induced molecular orientation by plastic deformation. With decreasing film thickness, viscosity and yield stress in viscoplasticity increase in an exponential and a linear trend, respectively, indicating the significant role of nanoconfinement effect on viscoplastic properties. These findings may reveal that there are many properties from linear viscoelasticity to nonlinear viscoelasticity-viscoplasticity that need to be explored and unveiled for sufficient understanding of the nanoconfinement effect on altering mechanical behavior of polymers.
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Affiliation(s)
- Yuhan Xiao
- University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Pei Bai
- University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhengyang Zhang
- University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yunlong Guo
- University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240, China
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2
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Nguyen HK, Goseki R, Ishizone T, Nakajima K. Effect of molecular weight and architecture on nanoscale viscoelastic heterogeneity at the surface of polymer films. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.123923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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3
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Plazek DJ, Ngai KL. Resolving the Sub-Rouse Modes by Creep Compliance Measurements in Poly(methyl- para-tolyl-siloxane). Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00536] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- D. J. Plazek
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - K. L. Ngai
- CNR-IPCF, Largo B. Pontecorvo 3, I-56127 Pisa, Italy
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4
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Ngai KL, Wojnarowska Z, Paluch M. The structural α-relaxation times of prilocaine confined in 1 nm pores of molecular sieves: quantitative explanation by the coupling model. Phys Chem Chem Phys 2020; 22:9257-9261. [PMID: 32307500 DOI: 10.1039/d0cp00282h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The molecular glass-former and pharmaceutical, prilocaine, distinguishes itself by exhibiting seven general and fundamental dynamic and thermodynamic properties [Z. Wojnarowska, et al., J. Phys. Chem. B, 2015, 39, 12699.], all of which have been explained using the coupling model. What has not been studied before are the changes in properties of the structural α-relaxation of prilocaine when subjected to extreme nano-confinement in spaces with a size of about 1 nm. Recently, Ruis et al. [G. N. Ruiz, et al., Phys. Chem. Chem. Phys., 2019, 21, 15576.] measured the α-relaxation times, τα,conf(T), of prilocaine confined in 1 nm pores of molecular sieves. They found that τα,conf(T) are significantly reduced from those of bulk prilocaine, τα,bulk(T), and assume a weaker temperature dependence. The data in toto pose a challenge for any theory of glass transition to explain quantitatively. The coupling model (CM) was applied to this problem to predict the α-relaxation times of prilocaine when cooperativity is removed, which is expected because only a few prilocaine molecules can fit into the 1 nm pores. The results from the CM are in quantitative agreement with the experimental values of τα,conf(T) and the temperature dependence. The success is nontrivial because no other extant theory can do the same to the best of our knowledge.
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Affiliation(s)
- K L Ngai
- CNR-IPCF, Dipartimento di Fisica, Largo Bruno Pontecorvo 3, I-56127, Pisa, Italy.
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5
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Ngai KL, Lunkenheimer P, Loidl A. Predicting the α-relaxation time of glycerol confined in 1.16 nm pores of zeolitic imidazolate frameworks. Phys Chem Chem Phys 2020; 22:507-511. [PMID: 31825416 DOI: 10.1039/c9cp05270d] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Uhl et al. [J. Chem. Phys., 2019, 150, 024504] studied the molecular dynamics of glycerol confined in a microporous zeolitic imidazolate framework (ZIF-8) with well-defined pore diameters of 1.16 nm by broadband dielectric spectroscopy. Of interest is a fast process in the central part of the pores identified as the α-relaxation of the confined supercooled glycerol with relaxation times τα,conf(T) reduced from τα,bulk(T) of bulk glycerol and having a temperature dependence different from the super-Arrhenius temperature of the latter. The focus of Uhl et al. was relating the confined molecular dynamics to the cooperativity length scales Lcorr(T) of molecular motion above the glass transition, and deducing the limiting high-temperature value of the correlation length of about 1.22 nm. Not yet considered by anyone are the observed values of τα,conf(T) and temperature dependence. Since the cooperativity length scales Lcorr(T) were found to be larger than the pore size of ZIF-8 over the temperature range studied and the density of the glycerol in the pore is possibly lower than the bulk, the cooperativity of the α-relaxation of glycerol confined in ZIF-8 is drastically reduced. Thus, within the framework of the Coupling Model (CM), τα,conf(T) should be nearly the same as the primitive relaxation time τ0(T) for glycerol when devoid of intermolecular coupling and cooperativity. Consistent with the absence of cooperativity of the glycerol confined in ZIF-8, we find the calculated τα,conf(T) are either the same or slightly longer than the calculated values of τ0(T). The quantitative prediction of the CM is verified. At this time we know of no other theory that can make such a quantitative prediction.
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Affiliation(s)
- K L Ngai
- CNR-IPCF, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy.
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6
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Nguyen HK, Sugimoto S, Konomi A, Inutsuka M, Kawaguchi D, Tanaka K. Dynamics Gradient of Polymer Chains near a Solid Interface. ACS Macro Lett 2019; 8:1006-1011. [PMID: 35619492 DOI: 10.1021/acsmacrolett.9b00351] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The relaxation dynamics of polyisoprene (PI) and nitrile butadiene rubber (NBR) chains at the SiO2 interface were directly probed as a function of distance from the SiO2 surface using time-resolved evanescent wave-induced fluorescence anisotropy, dielectric relaxation spectroscopy, and sum-frequency generation spectroscopy. We found the presence of the dynamics gradient of chains in the interfacial region with the SiO2 surface and tried to assign it to the two kinds of adsorbed chains, namely, loosely and strongly adsorbed, at the interface. The segmental relaxation of chains in the strongly adsorbed layer at the interface could be slower than that of bulk chains by more than 10 orders.
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7
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Ngai KL, Capaccioli S, Wang LM. Segmental α-Relaxation for the First Step and Sub-Rouse Modes for the Second Step in Enthalpy Recovery in the Glassy State of Polystyrene. Macromolecules 2019. [DOI: 10.1021/acs.macromol.8b02125] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- K. L. Ngai
- CNR-IPCF, Università 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
| | - Simone Capaccioli
- CNR-IPCF, Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa, Italy
| | - 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
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8
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Nguyen HK, Liang X, Ito M, Nakajima K. Direct Mapping of Nanoscale Viscoelastic Dynamics at Nanofiller/Polymer Interfaces. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01185] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Hung K. Nguyen
- Department of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan
| | - Xiaobin Liang
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan
| | - Makiko Ito
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan
| | - Ken Nakajima
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan
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9
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Ogieglo W, Ghanem B, Ma X, Wessling M, Pinnau I. High-Pressure CO 2 Sorption in Polymers of Intrinsic Microporosity under Ultrathin Film Confinement. ACS APPLIED MATERIALS & INTERFACES 2018; 10:11369-11376. [PMID: 29528618 DOI: 10.1021/acsami.8b01402] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Ultrathin microporous polymer films are pertinent to the development and further spread of nanotechnology with very promising potential applications in molecular separations, sensors, catalysis, or batteries. Here, we report high-pressure CO2 sorption in ultrathin films of several chemically different polymers of intrinsic microporosity (PIMs), including the prototypical PIM-1. Films with thicknesses down to 7 nm were studied using interference-enhanced in situ spectroscopic ellipsometry. It was found that all PIMs swell much more than non-microporous polystyrene and other high-performance glassy polymers reported previously. Furthermore, chemical modifications of the parent PIM-1 strongly affected the swelling magnitude. By investigating the behavior of relative refractive index, nrel, it was possible to study the interplay between micropores filling and matrix expansion. Remarkably, all studied PIMs showed a maximum in nrel at swelling of 2-2.5% indicating a threshold point above which the dissolution in the dense matrix started to dominate over sorption in the micropores. At pressures above 25 bar, all PIMs significantly plasticized in compressed CO2 and for the ones with the highest affinity to the penetrant, a liquidlike mixing typical for rubbery polymers was observed. Reduction of film thickness below 100 nm revealed pronounced nanoconfinement effects and resulted in a large swelling enhancement and a quick loss of the ultrarigid character. On the basis of the partial molar volumes of the dissolved CO2, the effective reduction of the Tg was estimated to be ∼200 °C going from 128 to 7 nm films.
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Affiliation(s)
- Wojciech Ogieglo
- DWI Leibniz Institute for Interactive Materials , Forckenbeckstr. 50 , 52074 Aachen , Germany
- Functional Polymer Membranes Group, Advanced Membranes and Porous Materials Center, Division of Physical Sciences and Engineering , King Abdullah University of Science and Technology (KAUST) , Thuwal, Jeddah 23955-6900 , Kingdom of Saudi Arabia
| | - Bader Ghanem
- Functional Polymer Membranes Group, Advanced Membranes and Porous Materials Center, Division of Physical Sciences and Engineering , King Abdullah University of Science and Technology (KAUST) , Thuwal, Jeddah 23955-6900 , Kingdom of Saudi Arabia
| | - Xiaohua Ma
- Functional Polymer Membranes Group, Advanced Membranes and Porous Materials Center, Division of Physical Sciences and Engineering , King Abdullah University of Science and Technology (KAUST) , Thuwal, Jeddah 23955-6900 , Kingdom of Saudi Arabia
| | - Matthias Wessling
- DWI Leibniz Institute for Interactive Materials , Forckenbeckstr. 50 , 52074 Aachen , Germany
| | - Ingo Pinnau
- Functional Polymer Membranes Group, Advanced Membranes and Porous Materials Center, Division of Physical Sciences and Engineering , King Abdullah University of Science and Technology (KAUST) , Thuwal, Jeddah 23955-6900 , Kingdom of Saudi Arabia
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10
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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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11
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Nguyen HK, Inutsuka M, Kawaguchi D, Tanaka K. Depth-resolved local conformation and thermal relaxation of polystyrene near substrate interface. J Chem Phys 2017; 146:203313. [DOI: 10.1063/1.4976523] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Hung Kim Nguyen
- Department of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan
| | - Manabu Inutsuka
- Department of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan
| | - Daisuke Kawaguchi
- Education Center for Global Leaders in Molecular Systems for Devices, Kyushu University, Fukuoka 819-0395, Japan
| | - Keiji Tanaka
- Department of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Fukuoka 819-0395, Japan
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12
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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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13
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14
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Ngai KL, Capaccioli S. Surface Diffusion of Polymer Glasses Redux. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- K. L. Ngai
- CNR-IPCF, Largo B. Pontecorvo
3, I-56127 Pisa, Italy
| | - Simone Capaccioli
- CNR-IPCF, Largo B. Pontecorvo
3, I-56127 Pisa, Italy
- Dipartimento di Fisica, Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa, Italy
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15
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Geng K, Tsui OKC. Effects of Polymer Tacticity and Molecular Weight on the Glass Transition Temperature of Poly(methyl methacrylate) Films on Silica. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00108] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Kun Geng
- Department
of Physics, Boston University, Boston, Massachusetts 02215, United States
| | - Ophelia K. C. Tsui
- Department
of Physics, Boston University, Boston, Massachusetts 02215, United States
- Division
of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, United States
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16
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Liu Y, Chen YC, Hutchens S, Lawrence J, Emrick T, Crosby AJ. Directly Measuring the Complete Stress–Strain Response of Ultrathin Polymer Films. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b01473] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yujie Liu
- Polymer
Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Yu-Cheng Chen
- Polymer
Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Shelby Hutchens
- Polymer
Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Jimmy Lawrence
- Polymer
Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Todd Emrick
- Polymer
Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Alfred J. Crosby
- Polymer
Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States
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17
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Nguyen HK, Wang D, Russell TP, Nakajima K. Observation of dynamical heterogeneities and their time evolution on the surface of an amorphous polymer. SOFT MATTER 2015; 11:1425-1433. [PMID: 25586672 DOI: 10.1039/c4sm02483d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Although the formation of dynamic heterogeneities in glass-forming materials is believed to play an essential role in determining their properties as the glass transition is approached, direct imaging of these heterogeneities remains a challenge. Here, we report on a direct observation of nanoscale dynamic heterogeneities and their time evolution over ~10(3) s on the surface of a glassy polymer, polystyrene (PS), using atomic force microscopy with a 1 nm radius tip. The length scale of these heterogeneities was measured to be ~2.1 nm and the lifetime was determined to be ~10(2) s, in agreement with the length and time scales of heterogeneous dynamics reported for bulk polymers around the glass transition. These results are consistent with the existence of a very thin liquid-like layer at the glassy polymer surface. The validity of the method is confirmed by comparing the properties of surface dynamics of neat and plasticized films.
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Affiliation(s)
- Hung K Nguyen
- WPI-Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan.
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18
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Prevosto D, Capaccioli S, Ngai KL. Origins of the two simultaneous mechanisms causing glass transition temperature reductions in high molecular weight freestanding polymer films. J Chem Phys 2014; 140:074903. [DOI: 10.1063/1.4865752] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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19
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Evans CM, Deng H, Jager WF, Torkelson JM. Fragility is a Key Parameter in Determining the Magnitude of Tg-Confinement Effects in Polymer Films. Macromolecules 2013. [DOI: 10.1021/ma401017n] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
| | | | - Wolter F. Jager
- Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628
BL Delft, The Netherlands
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20
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Zhu L, Wang X, Gu Q, Chen W, Sun P, Xue G. Confinement-Induced Deviation of Chain Mobility and Glass Transition Temperature for Polystyrene/Au Nanoparticles. Macromolecules 2013. [DOI: 10.1021/ma302643y] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lili Zhu
- Department of Polymer Science
and Engineering, The School of Chemistry and Chemical Engineering,
The State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China
| | - Xiaoliang Wang
- Department of Polymer Science
and Engineering, The School of Chemistry and Chemical Engineering,
The State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China
| | - Qiang Gu
- Department of Polymer Science
and Engineering, The School of Chemistry and Chemical Engineering,
The State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China
| | - Wei Chen
- Department of Polymer Science
and Engineering, The School of Chemistry and Chemical Engineering,
The State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China
| | - Pingchuan Sun
- Key Laboratory of Functional
Polymer Materials, Ministry of Education, Nankai University, Tianjin 300071, P. R. China
| | - Gi Xue
- Department of Polymer Science
and Engineering, The School of Chemistry and Chemical Engineering,
The State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China
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21
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Nguyen HK, Labardi M, Lucchesi M, Rolla P, Prevosto D. Plasticization in Ultrathin Polymer Films: The Role of Supporting Substrate and Annealing. Macromolecules 2013. [DOI: 10.1021/ma301980w] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hung K. Nguyen
- Dipartimento di Fisica “Enrico
Fermi”, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy
| | - Massimiliano Labardi
- CNR-IPCF, Consiglio Nazionale
delle Ricerche, Istituto per i Processi Chimico-Fisici, c/o Dip. Fisica, Largo Pontecorvo 3, 56127 Pisa, Italy
| | - Mauro Lucchesi
- Dipartimento di Fisica “Enrico
Fermi”, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy
| | - Pierangelo Rolla
- Dipartimento di Fisica “Enrico
Fermi”, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy
| | - Daniele Prevosto
- CNR-IPCF, Consiglio Nazionale
delle Ricerche, Istituto per i Processi Chimico-Fisici, c/o Dip. Fisica, Largo Pontecorvo 3, 56127 Pisa, Italy
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22
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Capaccioli S, Ngai KL, Paluch M, Prevosto D. Mechanism of fast surface self-diffusion of an organic glass. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:051503. [PMID: 23214785 DOI: 10.1103/physreve.86.051503] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 09/27/2012] [Indexed: 06/01/2023]
Abstract
Zhu et al. [L. Zhu, C. W. Brian, S. F. Swallen, P. T. Straus, M. D. Ediger, and L. Yu, Phys. Rev. Lett. 106, 256103 (2011)] measured the surface self-diffusion for an organic glass former, indomethacin, and found surface diffusion is more than 10(6) times faster than bulk diffusion at temperatures around T(g). With the help of dielectric relaxation and differential scanning calorimetry measurements on bulk indomethacin, and analysis of the data using the coupling model, we provide a quantitative explanation. We find the bulk α-relaxation time is longer than the primitive relaxation time also by about six orders of magnitude in a range of temperature above and below the bulk T(g). Thus, the cause of the fast surface diffusion is the nearly vanishing of intermolecular coupling of relaxation and diffusion at the surface. The results of related experimental studies of enhanced relaxation and diffusion at the surface of other glass formers also have been analyzed and quantitatively explained. Our predictions on surface diffusion from the coupling model are compared with that given by the random first order transition theory.
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Affiliation(s)
- S Capaccioli
- Physics Department, University of Pisa, Largo B Pontecorvo 3, I-56127 Pisa, Italy
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23
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Ngai KL, Prevosto D, Grassia L. Viscoelasticity of nanobubble-inflated ultrathin polymer films: Justification by the coupling model. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/polb.23201] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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24
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25
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Affiliation(s)
- C. M. Roland
- Naval Research Laboratory, Chemistry Division, Code 6120, Washington, D.C. 20375-5342
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Kim S, Hewlett SA, Roth CB, Torkelson JM. Confinement effects on glass transition temperature, transition breadth, and expansivity: comparison of ellipsometry and fluorescence measurements on polystyrene films. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2009; 30:83-92. [PMID: 19784679 DOI: 10.1140/epje/i2009-10510-y] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2009] [Revised: 08/03/2009] [Accepted: 08/21/2009] [Indexed: 05/28/2023]
Abstract
Using ellipsometry, we characterized the nanoconfinement effect on the glass transition temperature (T (g)of supported polystyrene (PS) films employing two methods: the intersection of fits to the temperature (Tdependences of rubbery- and glassy-state thicknesses, and the transition mid-point between rubbery- and glassy-state expansivities. The results demonstrate a strong effect of thickness: T(g) (bulk) - T(g)(23 nm) = 10 degrees C. The T -range needed for accurate measurement increases significantly with decreasing thickness, an effect that arises from the broadening of the transition with confinement and a region below T (g) where expansivity slowly decreases with decreasing T . As determined from expansivities, the T (g) breadth triples in going from bulk films to a 21-nm-thick film; this broadening of the transition may be a more dramatic effect of confinement than the T (g) reduction itself. In contrast, there is little effect of confinement on the rubbery- and glassy-state expansivities. Compared with ellipsometry, T (g) 's from fluorescence agree well in bulk films but yield lower values in nanoconfined films: T (g)(bulk) - T (g)(23 nm) = 15( degrees ) C via fluorescence. This small difference in the T (g) confinement effect reflects differences in how fluorescence and ellipsometry report "average T (g) " with confinement. With decreasing nanoscale thickness, fluorescence may slightly overweight the contribution of the free-surface layer while ellipsometry may evenly weight or underweight its contribution.
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Affiliation(s)
- S Kim
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, USA
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Narladkar A, Balnois E, Vignaud G, Grohens Y. Difference in Glass Transition Behavior Between Semi Crystalline and Amorphous poly(lactic acid) Thin Films. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/masy.200851321] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Wong SC, Baji A, Leng S. Effect of fiber diameter on tensile properties of electrospun poly(ɛ-caprolactone). POLYMER 2008. [DOI: 10.1016/j.polymer.2008.08.022] [Citation(s) in RCA: 282] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Fujii Y, Akabori KI, Tanaka K, Nagamura T. Chain Conformation Effects on Molecular Motions at the Surface of Poly(methyl methacrylate) Films. Polym J 2007. [DOI: 10.1295/polymj.pj2006270] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Priestley RD, Mundra MK, Barnett NJ, Broadbelt LJ, Torkelson JM. Effects of Nanoscale Confinement and Interfaces on the Glass Transition Temperatures of a Series of Poly(n-methacrylate) Films. Aust J Chem 2007. [DOI: 10.1071/ch07234] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We use fluorescence from dye-labelled polymer to measure the glass transition temperatures (Tgs) across single-layer films and near surfaces and silica interfaces in bilayer films for a series of poly(n-methacrylate)s. With nanoscale confinement, the average Tg across a film supported on silica increases for poly(methyl methacrylate) (PMMA), decreases for poly(ethyl methacrylate) (PEMA) and poly(propyl methacrylate), and is nearly invariant for poly(iso-butyl methacrylate) (PIBMA). These trends are consistent with the relative strengths of local perturbations to Tg caused by surfaces and substrates as measured in bilayer films. The substrate effect, which increases Tg via hydrogen-bonding interactions between the polymer and hydroxyl groups on the silica surface, is stronger than the free-surface effect in PMMA. The free-surface effect, which reduces Tg via a reduction in the required cooperativity of the glass transition dynamics, is stronger than the substrate effect in PEMA. The substrate and free-surface effects have similar strengths in perturbing the local Tg in PIBMA, resulting in a net cancellation of effects when measurements are made across single-layer films.
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