51
|
Schneider H, Saalwächter K, Roos M. Complex Morphology of the Intermediate Phase in Block Copolymers and Semicrystalline Polymers As Revealed by 1H NMR Spin Diffusion Experiments. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b00703] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Horst Schneider
- Institut für Physik - NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str. 7, 06120 Halle (Saale), Germany
| | - Kay Saalwächter
- Institut für Physik - NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str. 7, 06120 Halle (Saale), Germany
| | - Matthias Roos
- Institut für Physik - NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str. 7, 06120 Halle (Saale), Germany
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany St, Cambridge, Massachusetts 02139-4208, United States
| |
Collapse
|
52
|
Glass transition of poly (methyl methacrylate) filled with nanosilica and core-shell structured silica. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.08.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
53
|
Sharma RP, Green PF. Role of "Hard" and "Soft" Confinement on Polymer Dynamics at the Nanoscale. ACS Macro Lett 2017; 6:908-914. [PMID: 35650889 DOI: 10.1021/acsmacrolett.7b00374] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We investigated the segmental dynamics of asymmetrically confined polymer films and report an unusual phenomenon in which the presence and thickness of a soft confining layer are responsible for significant changes in the segmental dynamics of the confined films. Specifically, the segmental dynamics of poly(vinyl alcohol) (PVA) thin films asymmetrically confined between hard aluminum (Al), and soft polystyrene (PS) films are shown to shift by as much as half an order of magnitude upon changes in the thicknesses of the confining PS layer. These effects are more significant than those due to symmetric confinement between hard Al substrates or exposure to a free surface. These observations, partially rationalized in terms of recent simulations and theory, implicate the role of the moduli of the confining layers.
Collapse
Affiliation(s)
| | - Peter F. Green
- National
Renewable Energy Laboratory, Golden, Colorado 80401, United States
| |
Collapse
|
54
|
Dobies M, Makrocka-Rydzyk M, Jenczyk J, Jarek M, Spontak RJ, Jurga S. Molecular Dynamics Study of Polystyrene-b-poly(ethylene oxide) Asymmetric Diblock Copolymer Systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:8856-8868. [PMID: 28814072 DOI: 10.1021/acs.langmuir.7b02017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Two polystyrene-b-poly(ethylene oxide) (PS-b-PEO) diblock copolymers differing in molecular mass (49 and 78 kDa) but possessing the same PEO cylindrical morphology are examined to elucidate their molecular dynamics. Of particular interest here is the molecular motion of the PEO blocks involved in the rigid amorphous fraction (RAF). An analysis of complementary thermal calorimetry and X-ray scattering data confirms the presence of microphase-separated morphology as well as semicrystalline structure in each copolymer. Molecular motion within the copolymer systems is monitored by dielectric and nuclear magnetic resonance spectroscopies. The results reported herein reveal the existence of two local Arrhenius-type processes attributed to the noncooperative local motion of PEO segments involved in fully amorphous and rigid amorphous PEO microphases. In both systems, two structural relaxations governed by glass-transition phenomena are identified and assigned to cooperative segmental motion in the fully amorphous phase (the α process) and the RAF (the αc process). We measure the temperature dependence of the dynamics associated with all of the processes mentioned above and propose that these local processes are associated with corresponding cooperative segmental motion in both copolymer systems. In marked contrast to the thermal activation of the α process as discerned in both copolymers, the αc process appears to be a sensitive probe of the copolymer nanostructure. That is, the copolymer with shorter PEO blocks exhibits more highly restricted cooperative dynamics of PEO segments in the RAF, which can be explained in terms of the greater constraint imposed by the glassy PS matrix on the PEO blocks comprising smaller cylindrical microdomains.
Collapse
Affiliation(s)
| | | | | | | | - R J Spontak
- Departments of Chemical & Biomolecular Engineering and Materials Science & Engineering, North Carolina State University , Raleigh, North Carolina 27695, United States
| | | |
Collapse
|
55
|
Napolitano S, Sferrazza M. How irreversible adsorption affects interfacial properties of polymers. Adv Colloid Interface Sci 2017; 247:172-177. [PMID: 28202131 DOI: 10.1016/j.cis.2017.02.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 02/07/2017] [Accepted: 02/07/2017] [Indexed: 11/17/2022]
Abstract
Growing experimental evidence shows that the behavior of polymer chains confined at the nanoscale level strongly depends on the degree of adsorption correlated to the number density of monomers pinned onto the supporting substrate. In this contribution, after introducing the physics behind the mechanisms of irreversible adsorption, we review recent experimental observations on how adsorption affects properties of polymer melts confined in 1D, focusing on those related to the thermal glass transition, maximum water uptake, viscosity and crystallization. These findings strongly support a new physical framework of confined soft matter, not trivially limited to finite size effects and interfacial interactions, but also enriched by non-equilibrium phenomena.
Collapse
Affiliation(s)
- Simone Napolitano
- Laboratory of Polymer and Soft Matter Dynamics, Faculté des Sciences, Université Libre de Bruxelles (ULB), Boulevard du Triomphe, Bâtiment NO, Bruxelles 1050, Belgium.
| | - Michele Sferrazza
- Département de Physique, Faculté des Sciences, Université Libre de Bruxelles (ULB), Boulevard du Triomphe, Bruxelles 1050, Belgium
| |
Collapse
|
56
|
Carroll B, Cheng S, Sokolov AP. Analyzing the Interfacial Layer Properties in Polymer Nanocomposites by Broadband Dielectric Spectroscopy. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b00825] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
| | - Shiwang Cheng
- Chemical
Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Alexei P. Sokolov
- Chemical
Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| |
Collapse
|
57
|
Zhang W, Douglas JF, Starr FW. Effects of a “bound” substrate layer on the dynamics of supported polymer films. J Chem Phys 2017; 147:044901. [DOI: 10.1063/1.4994064] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] 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
| |
Collapse
|
58
|
Mangalara JH, Mackura ME, Marvin MD, Simmons DS. The relationship between dynamic and pseudo-thermodynamic measures of the glass transition temperature in nanostructured materials. J Chem Phys 2017; 146:203316. [DOI: 10.1063/1.4977520] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Affiliation(s)
- Jayachandra Hari Mangalara
- Department of Polymer Engineering, The University of Akron, 250 South Forge St, Akron, Ohio, 44325-0301 USA
| | - Mark E. Mackura
- Department of Polymer Engineering, The University of Akron, 250 South Forge St, Akron, Ohio, 44325-0301 USA
| | - Michael D. Marvin
- Department of Polymer Engineering, The University of Akron, 250 South Forge St, Akron, Ohio, 44325-0301 USA
| | - David S. Simmons
- Department of Polymer Engineering, The University of Akron, 250 South Forge St, Akron, Ohio, 44325-0301 USA
| |
Collapse
|
59
|
Cheng S, Carroll B, Bocharova V, Carrillo JM, Sumpter BG, Sokolov AP. Focus: Structure and dynamics of the interfacial layer in polymer nanocomposites with attractive interactions. J Chem Phys 2017; 146:203201. [DOI: 10.1063/1.4978504] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Shiwang Cheng
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Bobby Carroll
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Vera Bocharova
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Jan-Michael Carrillo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Bobby G. Sumpter
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Alexei P. Sokolov
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| |
Collapse
|
60
|
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
| |
Collapse
|
61
|
Tanis I, Meyer H, Salez T, Raphaël E, Maggs AC, Baschnagel J. Molecular dynamics simulation of the capillary leveling of viscoelastic polymer films. J Chem Phys 2017; 146:203327. [PMID: 28571341 DOI: 10.1063/1.4978938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Surface tension-driven flow techniques have recently emerged as an efficient means of shedding light into the rheology of thin polymer films. Motivated by experimental and theoretical approaches in films bearing a varying surface topography, we present results on the capillary relaxation of a square pattern at the free surface of a viscoelastic polymer film, using molecular dynamics simulations of a coarse-grained polymer model. Height profiles are monitored as a function of time after heating the system above its glass-transition temperature and their time dependence is fitted to the theory of capillary leveling. Results show that the viscosity is not constant, but time dependent. In addition to providing a complementary insight about the local inner mechanisms, our simulations of the capillary-leveling process therefore probe the viscoelasticity of the polymer and not only its viscosity, in contrast to most experimental approaches.
Collapse
Affiliation(s)
- I Tanis
- Laboratoire de Physico-Chimie Théorique, UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 75005 Paris, France
| | - H Meyer
- Université de Strasbourg, CNRS, Institut Charles Sadron, UPR 22, 67000 Strasbourg, France
| | - T Salez
- Laboratoire de Physico-Chimie Théorique, UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 75005 Paris, France
| | - E Raphaël
- Laboratoire de Physico-Chimie Théorique, UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 75005 Paris, France
| | - A C Maggs
- Laboratoire de Physico-Chimie Théorique, UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 75005 Paris, France
| | - J Baschnagel
- Université de Strasbourg, CNRS, Institut Charles Sadron, UPR 22, 67000 Strasbourg, France
| |
Collapse
|
62
|
Askar S, Wei T, Tan AW, Torkelson JM. Molecular weight dependence of the intrinsic size effect on T g in AAO template-supported polymer nanorods: A DSC study. J Chem Phys 2017; 146:203323. [PMID: 28571378 DOI: 10.1063/1.4978574] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Many studies have established a major effect of nanoscale confinement on the glass transition temperature (Tg) of polystyrene (PS), most commonly in thin films with one or two free surfaces. Here, we characterize smaller yet significant intrinsic size effects (in the absence of free surfaces or significant attractive polymer-substrate interactions) on the Tg and fragility of PS. Melt infiltration of various molecular weights (MWs) of PS into anodic aluminum oxide (AAO) templates is used to create nanorods supported on AAO with rod diameter (d) ranging from 24 to 210 nm. The Tg (both as Tg,onset and fictive temperature) and fragility values are characterized by differential scanning calorimetry. No intrinsic size effect is observed for 30 kg/mol PS in template-supported nanorods with d = 24 nm. However, effects on Tg are present for PS nanorods with Mn and Mw ≥ ∼175 kg/mol, with effects increasing in magnitude with increasing MW. For example, in 24-nm-diameter template-supported nanorods, Tg, rod - Tg, bulk = -2.0 to -2.5 °C for PS with Mn = 175 kg/mol and Mw = 182 kg/mol, and Tg, rod - Tg, bulk = ∼-8 °C for PS with Mn = 929 kg/mol and Mw = 1420 kg/mol. In general, reductions in Tg occur when d ≤ ∼2Rg, where Rg is the bulk polymer radius of gyration. Thus, intrinsic size effects are significant when the rod diameter is smaller than the diameter (2Rg) associated with the spherical volume pervaded by coils in bulk. We hypothesize that the Tg reduction occurs when chain segment packing frustration is sufficiently perturbed by confinement in the nanorods. This explanation is supported by observed reductions in fragility with the increasing extent of confinement. We also explain why these small intrinsic size effects do not contradict reports that the Tg-confinement effect in supported PS films with one free surface exhibits little or no MW dependence.
Collapse
Affiliation(s)
- Shadid Askar
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Tong Wei
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Anthony W Tan
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - John M Torkelson
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA
| |
Collapse
|
63
|
Baglay RR, Roth CB. Local glass transition temperatureTg(z) of polystyrene next to different polymers: Hard vs. soft confinement. J Chem Phys 2017; 146:203307. [DOI: 10.1063/1.4975168] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Roman R. Baglay
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
| | - Connie B. Roth
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
| |
Collapse
|
64
|
Chowdhury M, Guo Y, Wang Y, Merling WL, Mangalara JH, Simmons DS, Priestley RD. Spatially Distributed Rheological Properties in Confined Polymers by Noncontact Shear. J Phys Chem Lett 2017; 8:1229-1234. [PMID: 28256842 DOI: 10.1021/acs.jpclett.7b00214] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
When geometrically confined to the nanometer length scale, a condition in which a large portion of the material is in the nanoscale vicinity of interfaces, polymers can show astonishing changes in physical properties. In this investigation, we employ a unique noncontact capillary nanoshearing method to directly probe nanoresolved gradients in the rheological response of ultrathin polymer films as a function of temperature and stress. Results show that ultrathin polymer films, in response to an applied shear stress, exhibit a gradient in molecular mobility and viscosity that originates at the interfaces. We demonstrate, via molecular dynamics simulations, that these gradients in molecular mobility reflect gradients in the average segmental relaxation time and the glass-transition temperature.
Collapse
Affiliation(s)
| | - Yunlong Guo
- University of Michigan - Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University , Shanghai 200240, P. R. China
| | | | - Weston L Merling
- Department of Polymer Engineering, University of Akron , Akron, Ohio 44325, United States
| | | | - David S Simmons
- Department of Polymer Engineering, University of Akron , Akron, Ohio 44325, United States
| | | |
Collapse
|
65
|
Cheng S, Carroll B, Lu W, Fan F, Carrillo JMY, Martin H, Holt AP, Kang NG, Bocharova V, Mays JW, Sumpter BG, Dadmun M, Sokolov AP. Interfacial Properties of Polymer Nanocomposites: Role of Chain Rigidity and Dynamic Heterogeneity Length Scale. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02816] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Shiwang Cheng
- Chemical
Sciences Division, ‡Center for Nanophase Materials Sciences, and §Computational
Science and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics
and Astronomy and ⊥Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Bobby Carroll
- Chemical
Sciences Division, ‡Center for Nanophase Materials Sciences, and §Computational
Science and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics
and Astronomy and ⊥Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Wei Lu
- Chemical
Sciences Division, ‡Center for Nanophase Materials Sciences, and §Computational
Science and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics
and Astronomy and ⊥Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Fei Fan
- Chemical
Sciences Division, ‡Center for Nanophase Materials Sciences, and §Computational
Science and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics
and Astronomy and ⊥Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Jan-Michael Y. Carrillo
- Chemical
Sciences Division, ‡Center for Nanophase Materials Sciences, and §Computational
Science and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics
and Astronomy and ⊥Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Halie Martin
- Chemical
Sciences Division, ‡Center for Nanophase Materials Sciences, and §Computational
Science and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics
and Astronomy and ⊥Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Adam P. Holt
- Chemical
Sciences Division, ‡Center for Nanophase Materials Sciences, and §Computational
Science and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics
and Astronomy and ⊥Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Nam-Goo Kang
- Chemical
Sciences Division, ‡Center for Nanophase Materials Sciences, and §Computational
Science and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics
and Astronomy and ⊥Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Vera Bocharova
- Chemical
Sciences Division, ‡Center for Nanophase Materials Sciences, and §Computational
Science and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics
and Astronomy and ⊥Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Jimmy W. Mays
- Chemical
Sciences Division, ‡Center for Nanophase Materials Sciences, and §Computational
Science and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics
and Astronomy and ⊥Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Bobby G. Sumpter
- Chemical
Sciences Division, ‡Center for Nanophase Materials Sciences, and §Computational
Science and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics
and Astronomy and ⊥Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Mark Dadmun
- Chemical
Sciences Division, ‡Center for Nanophase Materials Sciences, and §Computational
Science and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics
and Astronomy and ⊥Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Alexei P. Sokolov
- Chemical
Sciences Division, ‡Center for Nanophase Materials Sciences, and §Computational
Science and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics
and Astronomy and ⊥Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| |
Collapse
|
66
|
Mangalara JH, Marvin MD, Wiener NR, Mackura ME, Simmons DS. Does fragility of glass formation determine the strength ofTg-nanoconfinement effects? J Chem Phys 2017; 146:104902. [DOI: 10.1063/1.4976521] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Jayachandra Hari Mangalara
- Department of Polymer Engineering, The University of Akron, 250 South Forge Street, Akron, Ohio 44325-0301, USA
| | - Michael D. Marvin
- Department of Polymer Engineering, The University of Akron, 250 South Forge Street, Akron, Ohio 44325-0301, USA
| | - Nicholas R. Wiener
- Department of Polymer Engineering, The University of Akron, 250 South Forge Street, Akron, Ohio 44325-0301, USA
| | - Mark E. Mackura
- Department of Polymer Engineering, The University of Akron, 250 South Forge Street, Akron, Ohio 44325-0301, USA
| | - David S. Simmons
- Department of Polymer Engineering, The University of Akron, 250 South Forge Street, Akron, Ohio 44325-0301, USA
| |
Collapse
|
67
|
Napolitano S, Glynos E, Tito NB. Glass transition of polymers in bulk, confined geometries, and near interfaces. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:036602. [PMID: 28134134 DOI: 10.1088/1361-6633/aa5284] [Citation(s) in RCA: 247] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
When cooled or pressurized, polymer melts exhibit a tremendous reduction in molecular mobility. If the process is performed at a constant rate, the structural relaxation time of the liquid eventually exceeds the time allowed for equilibration. This brings the system out of equilibrium, and the liquid is operationally defined as a glass-a solid lacking long-range order. Despite almost 100 years of research on the (liquid/)glass transition, it is not yet clear which molecular mechanisms are responsible for the unique slow-down in molecular dynamics. In this review, we first introduce the reader to experimental methodologies, theories, and simulations of glassy polymer dynamics and vitrification. We then analyse the impact of connectivity, structure, and chain environment on molecular motion at the length scale of a few monomers, as well as how macromolecular architecture affects the glass transition of non-linear polymers. We then discuss a revised picture of nanoconfinement, going beyond a simple picture based on interfacial interactions and surface/volume ratio. Analysis of a large body of experimental evidence, results from molecular simulations, and predictions from theory supports, instead, a more complex framework where other parameters are relevant. We focus discussion specifically on local order, free volume, irreversible chain adsorption, the Debye-Waller factor of confined and confining media, chain rigidity, and the absolute value of the vitrification temperature. We end by highlighting the molecular origin of distributions in relaxation times and glass transition temperatures which exceed, by far, the size of a chain. Fast relaxation modes, almost universally present at the free surface between polymer and air, are also remarked upon. These modes relax at rates far larger than those characteristic of glassy dynamics in bulk. We speculate on how these may be a signature of unique relaxation processes occurring in confined or heterogeneous polymeric systems.
Collapse
Affiliation(s)
- Simone Napolitano
- Laboratory of Polymer and Soft Matter Dynamics, Faculté des Sciences, Université Libre de Bruxelles (ULB), Boulevard du Triomphe, 1050 Brussels, Belgium
| | | | | |
Collapse
|
68
|
Voylov DN, Holt AP, Doughty B, Bocharova V, Meyer HM, Cheng S, Martin H, Dadmun M, Kisliuk A, Sokolov AP. Unraveling the Molecular Weight Dependence of Interfacial Interactions in Poly(2-vinylpyridine)/Silica Nanocomposites. ACS Macro Lett 2017; 6:68-72. [PMID: 35632893 DOI: 10.1021/acsmacrolett.6b00915] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The structure and polymer-nanoparticle interactions among physically adsorbed poly(2-vinylpyridine) chains on the surface of silica nanoparticles (NPs) were systematically studied as a function of molecular weight (MW) by sum frequency generation (SFG) and X-ray photoelectron (XPS) spectroscopies. Analysis of XPS data identified hydrogen bonds between the polymer and NPs, while SFG evaluated the change in the number of free OH sites on the NP's surface. Our data revealed that the hydrogen bonds and amount of the free -OH sites have a significant dependence on the polymer's MW. These results provide clear experimental evidence that the interaction of physically adsorbed chains with nanoparticles is strongly MW dependent and aids in unraveling the microscopic mechanism responsible for the strong MW dependence of dynamics of the interfacial layer in polymer nanocomposites.
Collapse
Affiliation(s)
- Dmitry N. Voylov
- Department of Chemistry and ‡Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37916-1600, United States
- Chemical Sciences Division and ∥Materials Science
and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Adam P. Holt
- Department of Chemistry and ‡Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37916-1600, United States
- Chemical Sciences Division and ∥Materials Science
and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Benjamin Doughty
- Department of Chemistry and ‡Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37916-1600, United States
- Chemical Sciences Division and ∥Materials Science
and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Vera Bocharova
- Department of Chemistry and ‡Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37916-1600, United States
- Chemical Sciences Division and ∥Materials Science
and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Harry M. Meyer
- Department of Chemistry and ‡Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37916-1600, United States
- Chemical Sciences Division and ∥Materials Science
and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Shiwang Cheng
- Department of Chemistry and ‡Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37916-1600, United States
- Chemical Sciences Division and ∥Materials Science
and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Halie Martin
- Department of Chemistry and ‡Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37916-1600, United States
- Chemical Sciences Division and ∥Materials Science
and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Mark Dadmun
- Department of Chemistry and ‡Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37916-1600, United States
- Chemical Sciences Division and ∥Materials Science
and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Alexander Kisliuk
- Department of Chemistry and ‡Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37916-1600, United States
- Chemical Sciences Division and ∥Materials Science
and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Alexei P. Sokolov
- Department of Chemistry and ‡Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37916-1600, United States
- Chemical Sciences Division and ∥Materials Science
and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| |
Collapse
|
69
|
Huang H, Dobryden I, Ihrner N, Johansson M, Ma H, Pan J, Claesson PM. Temperature-dependent surface nanomechanical properties of a thermoplastic nanocomposite. J Colloid Interface Sci 2017; 494:204-214. [PMID: 28160705 DOI: 10.1016/j.jcis.2017.01.096] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/24/2017] [Accepted: 01/24/2017] [Indexed: 11/26/2022]
Abstract
In polymer nanocomposites, particle-polymer interactions influence the properties of the matrix polymer next to the particle surface, providing different physicochemical properties than in the bulk matrix. This region is often referred to as the interphase, but detailed characterization of its properties remains a challenge. Here we employ two atomic force microscopy (AFM) force methods, differing by a factor of about 15 in probing rate, to directly measure the surface nanomechanical properties of the transition region between filler particle and matrix over a controlled temperature range. The nanocomposite consists of poly(ethyl methacrylate) (PEMA) and poly(isobutyl methacrylate) (PiBMA) with a high concentration of hydrophobized silica nanoparticles. Both AFM methods demonstrate that the interphase region around a 40-nm-sized particle located on the surface of the nanocomposite could extend to 55-70nm, and the interphase exhibits a gradient distribution in surface nanomechanical properties. However, the slower probing rate provides somewhat lower numerical values for the surface stiffness. The analysis of the local glass transition temperature (Tg) of the interphase and the polymer matrix provides evidence for reduced stiffness of the polymer matrix at high particle concentration, a feature that we attribute to selective adsorption. These findings provide new insight into understanding the microstructure and mechanical properties of nanocomposites, which is of importance for designing nanomaterials.
Collapse
Affiliation(s)
- Hui Huang
- Key Laboratory for Colloid and Interface Chemistry of State Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China; KTH Royal Institute of Technology, School of Chemical Sciences and Engineering, Department of Chemistry, Surface and Corrosion Science, Drottning Kristinas väg 51, SE-10044 Stockholm, Sweden.
| | - Illia Dobryden
- KTH Royal Institute of Technology, School of Chemical Sciences and Engineering, Department of Chemistry, Surface and Corrosion Science, Drottning Kristinas väg 51, SE-10044 Stockholm, Sweden
| | - Niklas Ihrner
- KTH Royal Institute of Technology, Department of Fiber and Polymer Technology, Teknikringen 56-58, SE-10044 Stockholm, Sweden
| | - Mats Johansson
- KTH Royal Institute of Technology, Department of Fiber and Polymer Technology, Teknikringen 56-58, SE-10044 Stockholm, Sweden
| | - Houyi Ma
- Key Laboratory for Colloid and Interface Chemistry of State Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Jinshan Pan
- KTH Royal Institute of Technology, School of Chemical Sciences and Engineering, Department of Chemistry, Surface and Corrosion Science, Drottning Kristinas väg 51, SE-10044 Stockholm, Sweden
| | - Per M Claesson
- KTH Royal Institute of Technology, School of Chemical Sciences and Engineering, Department of Chemistry, Surface and Corrosion Science, Drottning Kristinas väg 51, SE-10044 Stockholm, Sweden; SP Technical Research Institute of Sweden, SP Chemistry, Materials and Surfaces, Box 5607, SE-11486 Stockholm, Sweden.
| |
Collapse
|
70
|
Zhang L, Elupula R, Grayson SM, Torkelson JM. Suppression of the Fragility-Confinement Effect via Low Molecular Weight Cyclic or Ring Polymer Topology. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02280] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
| | - Ravinder Elupula
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Scott M. Grayson
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | | |
Collapse
|
71
|
Merling WL, Mileski JB, Douglas JF, Simmons DS. The Glass Transition of a Single Macromolecule. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01461] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Weston L. Merling
- Department
of Polymer Engineering, The University of Akron, 250 South Forge
St., Akron, Ohio 44325-0301, United States
| | - Johnathon B. Mileski
- Department
of Polymer Engineering, The University of Akron, 250 South Forge
St., Akron, Ohio 44325-0301, United States
| | - Jack F. Douglas
- Materials
Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - David S. Simmons
- Department
of Polymer Engineering, The University of Akron, 250 South Forge
St., Akron, Ohio 44325-0301, United States
| |
Collapse
|
72
|
Stiffness of thin, supported polystyrene films: Free-surface, substrate, and confinement effects characterized via self-referencing fluorescence. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.07.042] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
73
|
Holt AP, Bocharova V, Cheng S, Kisliuk AM, White BT, Saito T, Uhrig D, Mahalik JP, Kumar R, Imel AE, Etampawala T, Martin H, Sikes N, Sumpter BG, Dadmun MD, Sokolov AP. Controlling Interfacial Dynamics: Covalent Bonding versus Physical Adsorption in Polymer Nanocomposites. ACS NANO 2016; 10:6843-52. [PMID: 27337392 DOI: 10.1021/acsnano.6b02501] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
It is generally believed that the strength of the polymer-nanoparticle interaction controls the modification of near-interface segmental mobility in polymer nanocomposites (PNCs). However, little is known about the effect of covalent bonding on the segmental dynamics and glass transition of matrix-free polymer-grafted nanoparticles (PGNs), especially when compared to PNCs. In this article, we directly compare the static and dynamic properties of poly(2-vinylpyridine)/silica-based nanocomposites with polymer chains either physically adsorbed (PNCs) or covalently bonded (PGNs) to identical silica nanoparticles (RNP = 12.5 nm) for three different molecular weight (MW) systems. Interestingly, when the MW of the matrix is as low as 6 kg/mol (RNP/Rg = 5.4) or as high as 140 kg/mol (RNP/Rg= 1.13), both small-angle X-ray scattering and broadband dielectric spectroscopy show similar static and dynamic properties for PNCs and PGNs. However, for the intermediate MW of 18 kg/mol (RNP/Rg = 3.16), the difference between physical adsorption and covalent bonding can be clearly identified in the static and dynamic properties of the interfacial layer. We ascribe the differences in the interfacial properties of PNCs and PGNs to changes in chain stretching, as quantified by self-consistent field theory calculations. These results demonstrate that the dynamic suppression at the interface is affected by the chain stretching; that is, it depends on the anisotropy of the segmental conformations, more so than the strength of the interaction, which suggests that the interfacial dynamics can be effectively tuned by the degree of stretching-a parameter accessible from the MW or grafting density.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Nicole Sikes
- Department of Chemistry, Columbus State University , Columbus, Georgia 33232, United States
| | | | | | | |
Collapse
|
74
|
Mangalara JH, Marvin MD, Simmons DS. Three-Layer Model for the Emergence of Ultrastable Glasses from the Surfaces of Supercooled Liquids. J Phys Chem B 2016; 120:4861-5. [DOI: 10.1021/acs.jpcb.6b04736] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Jayachandra Hari Mangalara
- Department
of Polymer Engineering, The University of Akron, 250 South Forge
Street, Akron, Ohio 44325-0301, United States
| | - Michael D. Marvin
- Department
of Polymer Engineering, The University of Akron, 250 South Forge
Street, Akron, Ohio 44325-0301, United States
| | - David S. Simmons
- Department
of Polymer Engineering, The University of Akron, 250 South Forge
Street, Akron, Ohio 44325-0301, United States
| |
Collapse
|