1
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Xiao Y, Bai P, Guo Y. Modulus alteration of thin polystyrene films by their neighboring PDMS: Soft and hard confinement. J Chem Phys 2024; 160:211105. [PMID: 38832730 DOI: 10.1063/5.0209251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 05/17/2024] [Indexed: 06/05/2024] Open
Abstract
It is highly demanded to understand the confinement effect on nanoconfined polymers. Recent studies reported a strong perturbation of local dynamics and substantial alteration of glass transition temperature Tg at nanoscale. However, how confinement affects the mechanical properties of polymers is not fully understood. Here, we show that the modulus of thin polymer films could be remarkedly altered through a polymer-polymer interface. The modulus of a thin polystyrene (PS) film next to a polydimethylsiloxane (PDMS) was determined from the PS-PDMS bilayer bulging test. A series of experiments show that the modulus of PS can be increased up to 37%, when the modulus of the neighboring PDMS varies from 1.04 to 4.88 MPa. The results demonstrate a strong sensitivity of mechanical properties of thin polymers to the hard/soft environment, which we attribute to the change of high-mobility layer by the polymer-polymer interface.
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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
| | - 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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Cheng S, Kogut D, Zheng J, Patil S, Yang F, Lu W. Dynamics of polylactic acid under ultrafine nanoconfinement: The collective interface effect and the spatial gradient. J Chem Phys 2024; 160:114904. [PMID: 38506298 DOI: 10.1063/5.0189762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 02/16/2024] [Indexed: 03/21/2024] Open
Abstract
Polymers under nanoconfinement can exhibit large alterations in dynamics from their bulk values due to an interface effect. However, understanding the interface effect remains a challenge, especially in the ultrafine nanoconfinement region. In this work, we prepare new geometries with ultrafine nanoconfinement ∼10nm through controlled distributions of the crystalline phases and the amorphous phases of a model semi-crystalline polymer, i.e., the polylactic acid. The broadband dielectric spectroscopy measurements show that ultrafine nanoconfinement leads to a large elevation in the glass transition temperature and a strong increment in the polymer fragility index. Moreover, new relaxation time profile analyses demonstrate a spatial gradient that can be well described by either a single-exponential decay or a double-exponential decay functional form near the middle of the film with a collective interface effect. However, the dynamics at the 1-2 nm vicinity of the interface exhibit a power-law decay that is different from the single-exponential decay or double-exponential decay functional forms as predicted by theories. Thus, these results call for further investigations of the interface effect on polymer dynamics, especially for interfaces with perturbed chain packing.
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Affiliation(s)
- Shiwang Cheng
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, USA
| | - David Kogut
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, USA
| | - Juncheng Zheng
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, USA
| | - Shalin Patil
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, USA
| | - Fuming Yang
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, Michigan 48824, USA
| | - Weiyi Lu
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, Michigan 48824, USA
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3
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Hartley AD, Drayer WF, Ghanekarade A, Simmons DS. Interplay between dynamic heterogeneity and interfacial gradients in a model polymer film. J Chem Phys 2023; 159:204905. [PMID: 38032012 DOI: 10.1063/5.0165650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Glass-forming liquids exhibit long-lived, spatially correlated dynamical heterogeneity, in which some nm-scale regions in the fluid relax more slowly than others. In the nanoscale vicinity of an interface, glass-formers also exhibit the emergence of massive interfacial gradients in glass transition temperature Tg and relaxation time τ. Both of these forms of heterogeneity have a major impact on material properties. Nevertheless, their interplay has remained poorly understood. Here, we employ molecular dynamics simulations of polymer thin films in the isoconfigurational ensemble in order to probe how bulk dynamic heterogeneity alters and is altered by the large gradient in dynamics at the surface of a glass-forming liquid. Results indicate that the τ spectrum at the surface is broader than in the bulk despite being shifted to shorter times, and yet it is less spatially correlated. This is distinct from the bulk, where the τ distribution becomes broader and more spatially organized as the mean τ increases. We also find that surface gradients in slow dynamics extend further into the film than those in fast dynamics-a result with implications for how distinct properties are perturbed near an interface. None of these features track locally with changes in the heterogeneity of caging scale, emphasizing the local disconnect between these quantities near interfaces. These results are at odds with conceptions of the surface as reflecting simply a higher "rheological temperature" than the bulk, instead pointing to a complex interplay between bulk dynamic heterogeneity and spatially organized dynamical gradients at interfaces in glass-forming liquids.
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Affiliation(s)
- Austin D Hartley
- Department of Chemical, Biological, and Materials Engineering, The University of South Florida, Tampa, Florida 33620, USA
| | - William F Drayer
- Department of Chemical, Biological, and Materials Engineering, The University of South Florida, Tampa, Florida 33620, USA
| | - Asieh Ghanekarade
- Department of Chemical, Biological, and Materials Engineering, The University of South Florida, Tampa, Florida 33620, USA
| | - David S Simmons
- Department of Chemical, Biological, and Materials Engineering, The University of South Florida, Tampa, Florida 33620, USA
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4
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Wu X, Barner-Kowollik C. Fluorescence-readout as a powerful macromolecular characterisation tool. Chem Sci 2023; 14:12815-12849. [PMID: 38023522 PMCID: PMC10664555 DOI: 10.1039/d3sc04052f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 10/10/2023] [Indexed: 12/01/2023] Open
Abstract
The last few decades have witnessed significant progress in synthetic macromolecular chemistry, which can provide access to diverse macromolecules with varying structural complexities, topology and functionalities, bringing us closer to the aim of controlling soft matter material properties with molecular precision. To reach this goal, the development of advanced analytical techniques, allowing for micro-, molecular level and real-time investigation, is essential. Due to their appealing features, including high sensitivity, large contrast, fast and real-time response, as well as non-invasive characteristics, fluorescence-based techniques have emerged as a powerful tool for macromolecular characterisation to provide detailed information and give new and deep insights beyond those offered by commonly applied analytical methods. Herein, we critically examine how fluorescence phenomena, principles and techniques can be effectively exploited to characterise macromolecules and soft matter materials and to further unravel their constitution, by highlighting representative examples of recent advances across major areas of polymer and materials science, ranging from polymer molecular weight and conversion, architecture, conformation to polymer self-assembly to surfaces, gels and 3D printing. Finally, we discuss the opportunities for fluorescence-readout to further advance the development of macromolecules, leading to the design of polymers and soft matter materials with pre-determined and adaptable properties.
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Affiliation(s)
- Xingyu Wu
- School of Chemistry and Physics, Centre for Materials Science, Queensland University of Technology (QUT) 2 George Street Brisbane QLD 4000 Australia
| | - Christopher Barner-Kowollik
- School of Chemistry and Physics, Centre for Materials Science, Queensland University of Technology (QUT) 2 George Street Brisbane QLD 4000 Australia
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
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5
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Ghanekarade A, Simmons DS. Glass formation and dynamics of model polymer films with one versus two active interfaces. SOFT MATTER 2023; 19:8413-8422. [PMID: 37877245 DOI: 10.1039/d3sm00719g] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
Polymers and other glass-forming liquids can exhibit profound alterations in dynamics in the nanoscale vicinity of interfaces, over a range appreciably exceeding that of typical interfacial thermodynamic gradients. The understanding of these dynamical gradients is particularly complicated in systems with internal or external nanoscale dimensions, where a gradient nucleated at one interface can impinge on a second, potentially distinct, interface. To better understand the interactions that govern system dynamics and glass formation in these cases, here we simulate the baseline case of a glass-forming polymer film, over a wide range of thickness, supported on a dynamically neutral substrate that has little effect on nearby dynamics. We compare these results to our prior simulations of freestanding films. Results indicate that dynamical gradients in our simulated systems, as measured based upon translational relaxation, are simply truncated when they impinge on a secondary surface that is locally dynamically neutral. Altered film behavior can be described almost entirely by gradient effects down to the thinnest films probed, with no evidence for finite-size effects sometimes posited to play a role in these systems. Finally, our simulations predict that linear gradient overlap effects in the presence of symmetric dynamically active interfaces yield a non-monotonic variation of the whole free standing film stretching exponent (relaxation time distribution breadth). The maximum relaxation time distribution breadth in simulation is found at a film thickness of 4-5 times the interfacial gradient range. Observation of this maximum in experiment would provide an important validation that the gradient behavior observed in simulation persists to experimental timescales. If validated, observation of this maximum would potentially also enable determination of the dynamic gradient range from experimental mean-film measurements of film dynamics.
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Affiliation(s)
- Asieh Ghanekarade
- Department of Chemical, Biological, and Materials Engineering, The University of South Florida, Tampa, Florida, USA.
| | - David S Simmons
- Department of Chemical, Biological, and Materials Engineering, The University of South Florida, Tampa, Florida, USA.
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6
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Goswami M, Iyiola OO, Lu W, Hong K, Zolnierczuk P, Stingaciu LR, Heller WT, Taleb O, Sumpter BG, Hallinan DT. Understanding Interfacial Block Copolymer Structure and Dynamics. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c01814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Monojoy Goswami
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Oluwagbenga Oare Iyiola
- Chemical and Biomedical Engineering Department, Florida A&M University-Florida State University College of Engineering, Tallahassee, Florida 32310-6046, United States
- Aero-Propulsion, Mechatronics and Energy Center, Florida A&M University-Florida State University College of Engineering, Tallahassee, Florida 32310-6046, United States
| | - Wei Lu
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996-2200, United States
| | - Kunlun Hong
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996-2200, United States
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Piotr Zolnierczuk
- Juelich Center for Neutron Science, Outstation at the Spallation Neutron Source, Oak Ridge, Tennessee 37831-6473, United States
| | - Laura-Roxana Stingaciu
- Neutron Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - William T. Heller
- Neutron Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Omar Taleb
- Chemical and Biomedical Engineering Department, Florida A&M University-Florida State University College of Engineering, Tallahassee, Florida 32310-6046, United States
- Aero-Propulsion, Mechatronics and Energy Center, Florida A&M University-Florida State University College of Engineering, Tallahassee, Florida 32310-6046, United States
| | - Bobby G. Sumpter
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Daniel T. Hallinan
- Chemical and Biomedical Engineering Department, Florida A&M University-Florida State University College of Engineering, Tallahassee, Florida 32310-6046, United States
- Aero-Propulsion, Mechatronics and Energy Center, Florida A&M University-Florida State University College of Engineering, Tallahassee, Florida 32310-6046, United States
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7
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Ghanekarade A, Simmons DS. Combined Mixing and Dynamical Origins of Tg Alterations Near Polymer–Polymer Interfaces. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Asieh Ghanekarade
- Department of Chemical, Biological, and Materials Engineering, University of South Florida, Tampa, Florida33544, United States
| | - David S. Simmons
- Department of Chemical, Biological, and Materials Engineering, University of South Florida, Tampa, Florida33544, United States
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8
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Wang S, Luo Z, Liang J, Hu J, Jiang N, He J, Li Q. Polymer Nanocomposite Dielectrics: Understanding the Matrix/Particle Interface. ACS NANO 2022; 16:13612-13656. [PMID: 36107156 DOI: 10.1021/acsnano.2c07404] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Polymer nanocomposite dielectrics possess exceptional electric properties that are absent in the pristine dielectric polymers. The matrix/particle interface in polymer nanocomposite dielectrics is suggested to play decisive roles on the bulk material performance. Herein, we present a critical overview of recent research advances and important insights in understanding the matrix/particle interfacial characteristics in polymer nanocomposite dielectrics. The primary experimental strategies and state-of-the-art characterization techniques for resolving the local property-structure correlation of the matrix/particle interface are dissected in depth, with a focus on the characterization capabilities of each strategy or technique that other approaches cannot compete with. Limitations to each of the experimental strategy are evaluated as well. In the last section of this Review, we summarize and compare the three experimental strategies from multiple aspects and point out their advantages and disadvantages, critical issues, and possible experimental schemes to be established. Finally, the authors' personal viewpoints regarding the challenges of the existing experimental strategies are presented, and potential directions for the interface study are proposed for future research.
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Affiliation(s)
- Shaojie Wang
- State Key Laboratory of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084, China
| | - Zhen Luo
- State Key Laboratory of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084, China
| | - Jiajie Liang
- State Key Laboratory of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084, China
| | - Jun Hu
- State Key Laboratory of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084, China
| | - Naisheng Jiang
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Jinliang He
- State Key Laboratory of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084, China
| | - Qi Li
- State Key Laboratory of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084, China
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9
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Nasseri R, Moresoli C, Yu A, Yuan Z, Xu CC. Effect of Interphase Properties on Isothermal and Non-isothermal Crystallization Behavior of Poly(lactic acid)/Acetylated Starch Blends. ACS OMEGA 2022; 7:27851-27863. [PMID: 35990502 PMCID: PMC9386832 DOI: 10.1021/acsomega.2c00360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The effect of interphase properties on the crystallization behavior of blends of poly(lactic acid) (PLA)/acetylated starch (AS) with different degrees of substitution (DSs) was investigated. Under isothermal crystallization conditions, the rate of crystallization was higher for PLA/DS0.5 and lower for PLA/DS1.5 and PLA/DS2.5 when compared to PLA. In contrast, non-isothermal crystallization behavior indicated a slower rate of crystallization of PLA/DS0.5 and a faster rate of crystallization of PLA/DS1.5 and PLA/DS2.5 compared to PLA at the highest cooling rate (5 °C/min). The potential relationship between crystallization behavior and interphase properties and interphase thickness and formation of rigid amorphous fraction in the interphase, was investigated. The formation of a rigid amorphous fraction in PLA/DS1.5 and a thick interphase in PLA/DS2.5 prevented the formation of crystals on the dispersed phase and interrupted the crystallization under isothermal conditions. Hydrogen bonding in the PLA/DS1.5 blend and hydrophobic interactions in the PLA/DS2.5 blend may facilitate the crystallization at high cooling rates under non-isothermal conditions. Small-angle X-ray scattering analysis revealed the presence of a smaller lamellar structure in PLA/AS blends. The largest amorphous phase among blends was observed for the PLA/DS1.5 blend, which can be attributed to the hydrogen bonding in the interphase region of this blend.
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Affiliation(s)
- Rasool Nasseri
- Department
of Chemical Engineering, University of Waterloo, 200 University Avenue West, Waterloo N2L 3G1, Ontario, Canada
| | - Christine Moresoli
- Department
of Chemical Engineering, University of Waterloo, 200 University Avenue West, Waterloo N2L 3G1, Ontario, Canada
| | - Aiping Yu
- Department
of Chemical Engineering, University of Waterloo, 200 University Avenue West, Waterloo N2L 3G1, Ontario, Canada
- Waterloo
Institute for Nanotechnology, University
of Waterloo, 200 University
Avenue West, Waterloo N2L
3G1, Ontario, Canada
| | - Zhongshun Yuan
- Institute
for Chemicals and Fuels from Alternative Resources, Department of
Chemical & Biochemical Engineering, Western University, London N6A 5B9, Ontario, Canada
| | - Chunbao Charles Xu
- Institute
for Chemicals and Fuels from Alternative Resources, Department of
Chemical & Biochemical Engineering, Western University, London N6A 5B9, Ontario, Canada
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10
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Wang S, Fan L, Luo Z, Li J, Li L, He J, Li Q. Insight into the Experimental Error in the Mapping of Electrical Properties with Electrostatic Force Microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:8534-8544. [PMID: 35796005 DOI: 10.1021/acs.langmuir.2c00604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Electrostatic force microscopy (EFM) is an emergent, powerful technique for nanoscale detection of electrical properties such as permittivity and charge distribution. However, the surface irregularity of samples has been unfortunately overlooked in most EFM studies. Herein, we use a polymer nanocomposite dielectric (PND) as the showcase and demonstrate that the morphological discontinuity at the matrix/particle interface can lead to major discrepancies or even incorrect results in the EFM study. First, the influence of the morphology, permittivity, and charge density of the interface is quantitively analyzed with a numerical method, proving that linking EFM results directly to sample properties is impracticable in the research based on classical interface configuration. Then, two methods are proposed to address the issue. The first method is numerical inversion, which takes heterogeneous materials and irregular surfaces into consideration. In this method, the influence of several experimental uncertainties, such as the radius of the nanoparticle and the permittivity of the matrix, is estimated. It is shown that the uncertainties related to geometry have a great impact on inversion and should be determined preferentially. In the second method, two standard configurations of the interface are recommended and compared for the interface study to bypass the morphological issue. This work provides quantitative results regarding the long-overlooked error in the EFM detection of the microregion with heterogeneous composition and surface irregularities and offers methods to tackle this issue.
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Affiliation(s)
- Shaojie Wang
- State Key Laboratory of Power System, Department of Electrical Engineering, Tsinghua University, Beijing 100084, People's Republic of China
| | - Linzhen Fan
- State Key Laboratory of Power System, Department of Electrical Engineering, Tsinghua University, Beijing 100084, People's Republic of China
| | - Zhen Luo
- State Key Laboratory of Power System, Department of Electrical Engineering, Tsinghua University, Beijing 100084, People's Republic of China
| | - Junluo Li
- State Key Laboratory of Power System, Department of Electrical Engineering, Tsinghua University, Beijing 100084, People's Republic of China
| | - Lingfan Li
- State Key Laboratory of Power System, Department of Electrical Engineering, Tsinghua University, Beijing 100084, People's Republic of China
| | - Jinliang He
- State Key Laboratory of Power System, Department of Electrical Engineering, Tsinghua University, Beijing 100084, People's Republic of China
| | - Qi Li
- State Key Laboratory of Power System, Department of Electrical Engineering, Tsinghua University, Beijing 100084, People's Republic of China
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11
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Righetti MC, Vannini M, Celli A, Cangialosi D, Marega C. Bio-based semi-crystalline PEF: Temperature dependence of the constrained amorphous interphase and amorphous chain mobility in relation to crystallization. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.124771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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White RP, Lipson JEG. The dynamics of freestanding films: predictions for poly(2-chlorostyrene) based on bulk pressure dependence and thoughtful sample averaging. SOFT MATTER 2021; 17:9755-9764. [PMID: 34647951 DOI: 10.1039/d1sm01175h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In this paper we model the segmental relaxation in poly(2-chlorostyrene) 18 nm freestanding films, using only data on bulk samples to characterize the system, and predict film relaxation times (τ) as a function of temperature that are in semi-quantitative agreement with film data. The ability to translate bulk characterization into film predictions is a direct result of our previous work connecting the effects of free surfaces in films with those of changing pressure in the bulk. Our approach combines the Locally Correlated Lattice (LCL) equation of state for prediction of free volume values (Vfree) at any given density (ρ), which are then used in the Cooperative Free Volume (CFV) rate model to predict τ(T, Vfree). A key feature of this work is that we calculate the locally averaged density profile as a function of distance from the surface, ρav(z), using the CFV-predicted lengthscale, Lcoop(z), over which rearranging molecular segments cooperate. As we have shown in the past, ρav(z) is significantly broader than the localized profile, ρ(z), which translates into a relaxation profile, τ(z), exhibiting a breadth that mirrors experimental and simulated results. In addition, we discuss the importance of averaging the log of position dependent relaxation times across a film sample (〈log τ(z)〉), as opposed to averaging the relaxation times, themselves, in order to best approximate a whole sample-averaged value that can be directly compared to experiment.
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Affiliation(s)
- Ronald P White
- Department of Chemistry, Dartmouth College, Hanover, NH 03755, USA.
| | - Jane E G Lipson
- Department of Chemistry, Dartmouth College, Hanover, NH 03755, USA.
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13
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Han Y, Roth CB. Gradient in refractive index reveals denser near free surface region in thin polymer films. J Chem Phys 2021; 155:144901. [PMID: 34654302 DOI: 10.1063/5.0062054] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A gradient in refractive index that is linear in magnitude with depth into the film is used to fit ellipsometric data for thin polymer films of poly(methyl methacrylate) (PMMA), polystyrene (PS), and poly(2-vinyl pyridine) (P2VP). We find that the linear gradient model fits provide more physically realistic refractive index values for thin films compared with the commonly used homogeneous Cauchy layer model, addressing recent reports of physically unrealistic density increases. Counter to common expectations of a simple free volume correlation between density and dynamics, we find that the direction of refractive index (density) gradient indicates a higher density near the free surface, which we rationalize based on the observed faster free surface dynamics needed to create vapor deposited stable glasses with optimized denser molecular packings. The magnitude of refractive index gradient is observed to be three times larger for PMMA than for PS films, while P2VP films exhibit a more muted response possibly reflective of a decoupling in free surface and substrate dynamics in systems with strong interfacial interactions.
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Affiliation(s)
- Yixuan Han
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
| | - Connie B Roth
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
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14
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Ghanekarade A, Phan AD, Schweizer KS, Simmons DS. Nature of dynamic gradients, glass formation, and collective effects in ultrathin freestanding films. Proc Natl Acad Sci U S A 2021; 118:e2104398118. [PMID: 34326262 PMCID: PMC8346796 DOI: 10.1073/pnas.2104398118] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Molecular, polymeric, colloidal, and other classes of liquids can exhibit very large, spatially heterogeneous alterations of their dynamics and glass transition temperature when confined to nanoscale domains. Considerable progress has been made in understanding the related problem of near-interface relaxation and diffusion in thick films. However, the origin of "nanoconfinement effects" on the glassy dynamics of thin films, where gradients from different interfaces interact and genuine collective finite size effects may emerge, remains a longstanding open question. Here, we combine molecular dynamics simulations, probing 5 decades of relaxation, and the Elastically Cooperative Nonlinear Langevin Equation (ECNLE) theory, addressing 14 decades in timescale, to establish a microscopic and mechanistic understanding of the key features of altered dynamics in freestanding films spanning the full range from ultrathin to thick films. Simulations and theory are in qualitative and near-quantitative agreement without use of any adjustable parameters. For films of intermediate thickness, the dynamical behavior is well predicted to leading order using a simple linear superposition of thick-film exponential barrier gradients, including a remarkable suppression and flattening of various dynamical gradients in thin films. However, in sufficiently thin films the superposition approximation breaks down due to the emergence of genuine finite size confinement effects. ECNLE theory extended to treat thin films captures the phenomenology found in simulation, without invocation of any critical-like phenomena, on the basis of interface-nucleated gradients of local caging constraints, combined with interfacial and finite size-induced alterations of the collective elastic component of the structural relaxation process.
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Affiliation(s)
- Asieh Ghanekarade
- Department of Chemical, Biological and Materials Engineering, University of South Florida, Tampa, FL 33620
| | - Anh D Phan
- Faculty of Materials Science and Engineering, Phenikaa University, Hanoi 12116, Vietnam;
| | - Kenneth S Schweizer
- Department of Materials Science, University of Illinois, Urbana, IL 61801;
- Department of Chemistry, University of Illinois, Urbana, IL 61801
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL 61801
| | - David S Simmons
- Department of Chemical, Biological and Materials Engineering, University of South Florida, Tampa, FL 33620;
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15
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Roth CB. Polymers under nanoconfinement: where are we now in understanding local property changes? Chem Soc Rev 2021; 50:8050-8066. [PMID: 34086025 DOI: 10.1039/d1cs00054c] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Polymers are increasingly being used in applications with nanostructured morphologies where almost all polymer molecules are within a few tens to hundreds of nanometers from some interface. From nearly three decades of study on polymers in simplified nanoconfined systems such as thin films, we have come to understand property changes in these systems as arising from interfacial effects where local dynamical perturbations are propagated deeper into the material. This review provides a summary of local glass transition temperature Tg changes near interfaces, comparing across different types of interfaces: free surface, substrate, liquid, and polymer-polymer. Local versus film-average properties in thin films are discussed, making connections to other related property changes, while highlighting several historically important studies. By experimental necessity, most studies are on high enough molecule weight chains to be well entangled, although aspects that connect to lower molecule weight materials are described. Emphasis is made to identify observations and open questions that have yet to be fully understood such as the evidence of long-ranged interfacial effects, finite domain size, interfacial breadth, and chain connectivity.
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Affiliation(s)
- Connie B Roth
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA.
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16
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Righetti MC, Di Lorenzo ML, Cinelli P, Gazzano M. Temperature dependence of the rigid amorphous fraction of poly(butylene succinate). RSC Adv 2021; 11:25731-25737. [PMID: 35478875 PMCID: PMC9036998 DOI: 10.1039/d1ra03775g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 06/16/2021] [Indexed: 11/21/2022] Open
Abstract
In this contribution the temperature evolution of the constrained or rigid amorphous fraction (RAF) of biodegradable and biocompatible poly(butylene succinate) (PBS) was quantified, after detailed thermodynamic characterization by differential scanning calorimetry and X-ray diffraction analysis. At the glass transition temperature, around -40 °C, the rigid amorphous fraction in PBS is about 0.25. It decreases with increasing temperature and becomes zero in proximity of 25 °C. Thus, at room temperature and at the human body temperature, all the amorphous fraction is mobile. This information is important for the development of PBS products for various applications, including biomedical applications, since physical properties of the rigid amorphous fraction, for example mechanical and permeability properties, are different from those of the mobile amorphous fraction.
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Affiliation(s)
- Maria Cristina Righetti
- CNR-IPCF, National Research Council - Institute for Chemical and Physical Processes Via Moruzzi 1 56124 Pisa Italy
| | - Maria Laura Di Lorenzo
- CNR-IPCB, National Research Council - Institute of Polymers, Composites and Biomaterials Via Campi Flegrei 24 80078 Pozzuoli Italy
| | - Patrizia Cinelli
- University of Pisa, Department of Civil and Industrial Engineering Largo Lazzarino 2 56122 Pisa Italy
| | - Massimo Gazzano
- CNR-ISOF, National Research Council - Institute of Organic Synthesis and Photoreactivity Via Gobetti 101 40129 Bologna Italy
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17
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Rahman T, Simmons DS. Near-Substrate Gradients in Chain Relaxation and Viscosity in a Model Low-Molecular Weight Polymer. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02888] [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)
- Tamanna Rahman
- Department of Polymer Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - David S. Simmons
- Department of Chemical, Biological, and Materials Engineering, University of South Florida, Tampa, Florida 33620, United States
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18
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White RP, Lipson JEG. Dynamics across a Free Surface Reflect Interplay between Density and Cooperative Length: Application to Polystyrene. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02742] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ronald P. White
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Jane E. G. Lipson
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
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19
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White RP, Lipson JEG. A Simple New Way To Account for Free Volume in Glassy Dynamics: Model-Free Estimation of the Close-Packed Volume from PVT Data. J Phys Chem B 2021; 125:4221-4231. [PMID: 33861608 DOI: 10.1021/acs.jpcb.1c01620] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this article we focus on the important role of well-defined free volume (Vfree) in dictating the structural relaxation times, τ, of glass-forming liquids and polymer melts. Our definition of Vfree = V - Vhc, where V is the total system volume, means the use of Vfree depends on determination of Vhc, the system's volume in the limiting closely packed state. Rejecting the historically compromised use of Vfree as a dynamics-dependent fitting function, we have successfully applied a clear thermodynamics-based route to Vhc using the locally correlated lattice (LCL) model equation of state (EOS). However, in this work we go further and show that Vhc can be defined without the use of an equation of state by direct linear extrapolation of a V(T) high-pressure isobar down to zero temperature (T). The results from this route, tested on a dozen experimental systems, yield ln τ vs 1/Vfree isotherms that are linear with T-dependent slopes, consistent with the general ln τ ∼ f(T) × (1/Vfree) form of behavior we have previously described. This functional form also results by implementing a simple mechanistic explanation via the cooperative free volume (CFV) rate model, which assumes that dynamic relaxation is both thermally activated and that it requires molecular segmental cooperativity. With the degree of the latter, and thus the activation energy, being determined by the availability of free volume, the new route we demonstrate here for determination of Vfree expands the potential for understanding and predicting local dynamic relaxation in glass-forming materials.
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Affiliation(s)
- Ronald P White
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Jane E G Lipson
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
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20
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Schneider H, Roos M, Golitsyn Y, Steiner K, Saalwächter K. Dynamic Heterogeneity of Filler-Associated Interphases in Polymer Nanocomposites. Macromol Rapid Commun 2021; 42:e2100061. [PMID: 33759277 DOI: 10.1002/marc.202100061] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/26/2021] [Indexed: 11/08/2022]
Abstract
Dynamically inhomogeneous polymer systems exhibit interphases with mobility gradients. These are believed to play key roles in the material's performance. A prominent example is particle-filled rubber, a special case of a crosslinked polymer nanocomposite, where favorable rubber-filler interactions may give rise to a nanoscale immobilized layer around the filler, including regions of intermediate mobility. Such intermediate domains may either form a separate shell-like layer or be a manifestation of dynamic heterogeneities, in which case the intermediately mobile material would be dispersed in the form of nanometer-sized subdomains. In this contribution, bidirectional proton NMR spin diffusion (SD) experiments applied to silica-filled acrylate rubber are combined with numerical simulations to provide microscopic insights into this question. While model calculations for different scenarios fit the given data similarly well for longer SD mixing time, the short-time data do support the presence of dynamic heterogeneities.
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Affiliation(s)
- Horst Schneider
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str. 7, Halle, 06120, Germany
| | - Matthias Roos
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str. 7, Halle, 06120, Germany
| | - Yury Golitsyn
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str. 7, Halle, 06120, Germany
| | - Kerstin Steiner
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str. 7, Halle, 06120, Germany
| | - Kay Saalwächter
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str. 7, Halle, 06120, Germany
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21
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Gagnon YJ, Roth CB. Local Glass Transition Temperature Tg( z) Within Polystyrene Is Strongly Impacted by the Modulus of the Neighboring PDMS Domain. ACS Macro Lett 2020; 9:1625-1631. [PMID: 35617064 DOI: 10.1021/acsmacrolett.0c00659] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Profiles in the local glass transition temperature Tg(z) within polystyrene (PS) next to polydimethylsiloxane (PDMS) domains were determined using a localized fluorescence method. By changing the base to cross-linker ratio, we varied the cross-link density and, hence, the Young's modulus of PDMS (Sylgard 184). The local Tg(z) in PS at a distance of z = 50 nm away from the PS/PDMS interface was found to shift by 40 K as the PDMS modulus was varied from 0.9 to 2.6 MPa, demonstrating a strong sensitivity of this phenomenon to the rigidity of the neighboring domain. The extent the Tg(z) perturbation persists away from the PS/PDMS interface, z ≈ 65-90 nm before bulk Tg is recovered, is much shorter for this strongly immiscible system compared with the weakly immiscible systems studied previously, which we attribute to a smaller interfacial width, as the χ parameter for PS/PDMS is an order of magnitude larger.
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Affiliation(s)
- Yannic J. Gagnon
- Department of Physics, Emory University, Atlanta, Georgia 30322, United States
| | - Connie B. Roth
- Department of Physics, Emory University, Atlanta, Georgia 30322, United States
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22
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Li L, Qiang Z, Chen X, Jin K, Wang M, Torkelson JM. Impact of bottlebrush chain architecture on
T
g
‐confinement and
fragility‐confinement
effects enabled by thermo‐cleavable bottlebrush polymers synthesized by radical coupling and atom transfer radical polymerization. JOURNAL OF POLYMER SCIENCE 2020. [DOI: 10.1002/pol.20200537] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Lingqiao Li
- Department of Chemical and Biological Engineering Northwestern University Evanston Illinois USA
| | - Zhe Qiang
- Department of Chemical and Biological Engineering Northwestern University Evanston Illinois USA
| | - Xi Chen
- Department of Chemical and Biological Engineering Northwestern University Evanston Illinois USA
| | - Kailong Jin
- Department of Chemical and Biological Engineering Northwestern University Evanston Illinois USA
| | - Muzhou Wang
- Department of Chemical and Biological Engineering Northwestern University Evanston Illinois USA
| | - John M. Torkelson
- Department of Chemical and Biological Engineering Northwestern University Evanston Illinois USA
- Department of Materials Science and Engineering Northwestern University Evanston Illinois USA
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23
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White RP, Lipson JEG. To Understand Film Dynamics Look to the Bulk. PHYSICAL REVIEW LETTERS 2020; 125:058002. [PMID: 32794834 DOI: 10.1103/physrevlett.125.058002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/27/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
We show that shifts in dynamics of confined systems relative to that of the bulk material originate in the properties of bulk alone, and exhibit the same form of behavior as when different bulk isobars are compared. For bulk material, pressure-dependent structural relaxation times follow τ(T,V)∝exp[f(T)×g(V)]. When two states (isobars) of the material, "1" and "2", are compared at the same temperature this leads to a form τ_{2}∝τ_{1}^{c}, where c=g[V_{2}(T)]/g[V_{1}(T)]. Using equation of state analysis and two models for P-dependent dynamics, we show that c is approximately T independent, and that it can be very simply expressed in terms of either the (free) volume above the close packed state (V_{free}) or the activation energy for cooperative motion. The effect of changing state through a shift in pressure (P_{1} to P_{2}) is thus mechanistically traceable to cooperativity changing with density, through V_{free}. The connection with confined dynamics follows when 1 and 2 are taken as bulk and film at ambient P, differing in density only due to the film surface. The general form for τ(T,V) also illuminates why samples in different states (film vs bulk, high P vs low) trend toward the same relaxation behavior at high T.
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Affiliation(s)
- Ronald P White
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - Jane E G Lipson
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, USA
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24
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Diaz Vela D, Ghanekarade A, Simmons DS. Probing the Metrology and Chemistry Dependences of the Onset Condition of Strong “Nanoconfinement” Effects on Dynamics. Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b02693] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Daniel Diaz Vela
- Department of Chemical and Biomedical Engineering, The University of South Florida, Tampa, Florida 33620, United States
| | - Asieh Ghanekarade
- Department of Chemical and Biomedical Engineering, The University of South Florida, Tampa, Florida 33620, United States
| | - David S. Simmons
- Department of Chemical and Biomedical Engineering, The University of South Florida, Tampa, Florida 33620, United States
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25
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Bailey EJ, Winey KI. Dynamics of polymer segments, polymer chains, and nanoparticles in polymer nanocomposite melts: A review. Prog Polym Sci 2020. [DOI: 10.1016/j.progpolymsci.2020.101242] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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26
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Register RA. Morphology and Structure–Property Relationships in Random Ionomers: Two Foundational Articles from Macromolecules. Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b01932] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Richard A. Register
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
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27
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Cheng S, Sokolov AP. Correlation between the temperature evolution of the interfacial region and the growing dynamic cooperativity length scale. J Chem Phys 2020; 152:094904. [PMID: 33480747 DOI: 10.1063/1.5143360] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Shiwang Cheng
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, USA
| | - Alexei P. Sokolov
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
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28
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Schweizer KS, Simmons DS. Progress towards a phenomenological picture and theoretical understanding of glassy dynamics and vitrification near interfaces and under nanoconfinement. J Chem Phys 2019; 151:240901. [PMID: 31893888 DOI: 10.1063/1.5129405] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The nature of alterations to dynamics and vitrification in the nanoscale vicinity of interfaces-commonly referred to as "nanoconfinement" effects on the glass transition-has been an open question for a quarter century. We first analyze experimental and simulation results over the last decade to construct an overall phenomenological picture. Key features include the following: after a metrology- and chemistry-dependent onset, near-interface relaxation times obey a fractional power law decoupling relation with bulk relaxation; relaxation times vary in a double-exponential manner with distance from the interface, with an intrinsic dynamical length scale appearing to saturate at low temperatures; the activation barrier and vitrification temperature Tg approach bulk behavior in a spatially exponential manner; and all these behaviors depend quantitatively on the nature of the interface. We demonstrate that the thickness dependence of film-averaged Tg for individual systems provides a poor basis for discrimination between different theories, and thus we assess their merits based on the above dynamical gradient properties. Entropy-based theories appear to exhibit significant inconsistencies with the phenomenology. Diverse free-volume-motivated theories vary in their agreement with observations, with approaches invoking cooperative motion exhibiting the most promise. The elastically cooperative nonlinear Langevin equation theory appears to capture the largest portion of the phenomenology, although important aspects remain to be addressed. A full theoretical understanding requires improved confrontation with simulations and experiments that probe spatially heterogeneous dynamics within the accessible 1-ps to 1-year time window, minimal use of adjustable parameters, and recognition of the rich quantitative dependence on chemistry and interface.
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Affiliation(s)
- Kenneth S Schweizer
- Departments of Materials Science, Chemistry and Chemical & Biomolecular Engineering, Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
| | - David S Simmons
- Department of Chemical and Biomedical Engineering, University of South Florida, Tampa, Florida 33620, USA
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29
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Wang T, Yan J, Yuan H, Xu J, Lam HY, Yu X, Lv C, Du B, Tsui OKC. Tg Confinement Effect of Random Copolymers of 4- tert-Butylstyrene and 4-Acetoxystyrene with Different Compositions. ACS Macro Lett 2019; 8:1280-1284. [PMID: 35651168 DOI: 10.1021/acsmacrolett.9b00568] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We observe that the Tg confinement effect of polymer films can saturate with polymer-substrate interaction. Thickness dependences of the glass transition temperature, Tg(h0), of random copolymer films of 4-tert-butylstyrene (TBS) and 4-acetoxystyrene (AS) supported by silica (SiOx) were measured for different TBS concentrations, XTBS. For 0 ≤ XTBS ≤ 0.47, Tg(h0) displays identical enhancements, independent of XTBS. For XTBS > ∼0.66; however, Tg(h0) decreases steadily with XTBS. The XTBS > 0.66 result is in keeping with expectations that TBS interacts less strongly with SiOx than AS does, and weaker polymer-substrate interaction renders greater dominance of the air surface over substrate surface on Tg, and thereby Tg reduction. We propose that saturation in Tg(h0) found for XTBS ≤ 0.47 is caused by the maximization in polymer-substrate-specific bond formation. Further experiments and a calculation support this proposition.
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Affiliation(s)
- Tong Wang
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Jinsong Yan
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Hailin Yuan
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Jianquan Xu
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Ho Yi Lam
- Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Xuanji Yu
- Division of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, United States
| | - Chao Lv
- Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Binyang Du
- Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Ophelia K. C. Tsui
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
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30
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Zhang W, Emamy H, Pazmiño Betancourt BA, Vargas-Lara F, Starr FW, Douglas JF. The interfacial zone in thin polymer films and around nanoparticles in polymer nanocomposites. J Chem Phys 2019; 151:124705. [DOI: 10.1063/1.5119269] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Wengang Zhang
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA
- Materials Science and Engineering, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Hamed Emamy
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA
- Department of Chemical Engineering, Columbia University, New York, New York 10027, USA
| | - Beatriz A. Pazmiño Betancourt
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA
- Materials Science and Engineering, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Fernando Vargas-Lara
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA
- Materials Science and Engineering, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Francis W. Starr
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA
| | - Jack F. Douglas
- Materials Science and Engineering, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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31
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Giunta G, Carbone P. Cross-over in the dynamics of polymer confined between two liquids of different viscosity. Interface Focus 2019; 9:20180074. [PMID: 31065342 PMCID: PMC6501349 DOI: 10.1098/rsfs.2018.0074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2019] [Indexed: 11/12/2022] Open
Abstract
Using molecular dynamics simulations, we analysed the polymer dynamics of chains of different molecular weights entrapped at the interface between two immiscible liquids. We showed that on increasing the viscosity of one of the two liquids the dynamic behaviour of the chain changes from a Zimm-like dynamics typical of dilute polymer solutions to a Rouse-like dynamics where hydrodynamic interactions are screened. We observed that when the polymer is in contact with a high viscosity liquid, the number of solvent molecules close to the polymer beads is reduced and ascribed the screening effect to this reduced number of polymer-solvent contacts. For the longest chain simulated, we calculated the distribution of loop length and compared the results with the theoretical distribution developed for solid/liquid interfaces. We showed that the polymer tends to form loops (although flat against the interface) and that the theory works reasonably well also for liquid/liquid interfaces.
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Affiliation(s)
- Giuliana Giunta
- School of Chemical Engineering and Analytical Science, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Paola Carbone
- School of Chemical Engineering and Analytical Science, University of Manchester, Oxford Road, Manchester M13 9PL, UK
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32
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Yu X, Wang T, Tsui OKC, Weng LT. Tuning the Effective Viscosity of Polymer Films by Chemical Modifications. Macromolecules 2019. [DOI: 10.1021/acs.macromol.8b02699] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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33
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Qian Z, Cao Z, Galuska L, Zhang S, Xu J, Gu X. Glass Transition Phenomenon for Conjugated Polymers. MACROMOL CHEM PHYS 2019. [DOI: 10.1002/macp.201900062] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Zhiyuan Qian
- School of Polymer Science and Engineering Center for Optoelectronic Materials and Device The University of Southern Mississippi Hattiesburg MS 39406 USA
| | - Zhiqiang Cao
- School of Polymer Science and Engineering Center for Optoelectronic Materials and Device The University of Southern Mississippi Hattiesburg MS 39406 USA
| | - Luke Galuska
- School of Polymer Science and Engineering Center for Optoelectronic Materials and Device The University of Southern Mississippi Hattiesburg MS 39406 USA
| | - Song Zhang
- School of Polymer Science and Engineering Center for Optoelectronic Materials and Device The University of Southern Mississippi Hattiesburg MS 39406 USA
| | - Jie Xu
- Argonne National Laboratory Lemont IL 60439 USA
| | - Xiaodan Gu
- School of Polymer Science and Engineering Center for Optoelectronic Materials and Device The University of Southern Mississippi Hattiesburg MS 39406 USA
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34
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Smith SM, Simmons DS. Poisson ratio mismatch drives low-strain reinforcement in elastomeric nanocomposites. SOFT MATTER 2019; 15:656-670. [PMID: 30617354 DOI: 10.1039/c8sm02333f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Introduction of nanoparticulate additives can dramatically impact elastomer mechanical response, with large enhancements in modulus, toughness, and strength. Despite the societal importance of these effects, their mechanistic origin remains unsettled. Here, using a combination of theory and molecular dynamics simulation, we show that low-strain extensional reinforcement of elastomers is driven by a nanoparticulate-jamming-induced suppression in the composite Poisson ratio. This suppression forces an increase in rubber volume with extensional deformation, effectively converting a portion of the rubber's bulk modulus into an extensional modulus. A theory describing this effect is shown to interrelate the Poisson ratio and modulus across a matrix of simulated elastomeric nanocomposites of varying loading and nanoparticle structure. This model provides a design rule for structured nanoparticulates that maximizes elastomer mechanical response via suppression of the composite Poisson ratio. It also positions elastomeric nanocomposites as having a qualitatively different character than Poisson-ratio-matched plastic nanocomposites, where this mechanism is absent.
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Affiliation(s)
- Scott M Smith
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325, USA
| | - David S Simmons
- Department of Chemical and Biomedical Engineering, University of South Florida, Tampa, Florida 33620, USA.
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35
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Debot A, White RP, Lipson JEG, Napolitano S. Experimental Test of the Cooperative Free Volume Rate Model under 1D Confinement: The Interplay of Free Volume, Temperature, and Polymer Film Thickness in Driving Segmental Mobility. ACS Macro Lett 2019; 8:41-45. [PMID: 35619409 DOI: 10.1021/acsmacrolett.8b00844] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We show that the Cooperative Free Volume (CFV) rate model, successful at modeling pressure-dependent dynamics, can be employed to describe the temperature and thickness dependence of the segmental time of polymers confined in thin films (1D confinement). The CFV model is based on an activation free energy that increases with the number of cooperating segments, which is determined by the system's free volume. Here, we apply the CFV model to new experimental results on the segmental relaxation of 1D confined poly(4-chlorostyrene), P4ClS, and find remarkable agreement over the whole temperature and thickness ranges investigated. This work further validates the robustness of the CFV model, which relates the effects of confinement on dynamics to pressure changes in the bulk, and supports the idea that confinement effects originate from local perturbations in density.
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Affiliation(s)
- Alice Debot
- Polymer and Soft Matter Dynamics, Faculté des Sciences, Université libre de Bruxelles (ULB), Brussels, Belgium
| | - Ronald P. White
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Jane E. G. Lipson
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Simone Napolitano
- Polymer and Soft Matter Dynamics, Faculté des Sciences, Université libre de Bruxelles (ULB), Brussels, Belgium
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36
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Diaz-Vela D, Hung JH, Simmons DS. Temperature-Independent Rescaling of the Local Activation Barrier Drives Free Surface Nanoconfinement Effects on Segmental-Scale Translational Dynamics near Tg. ACS Macro Lett 2018; 7:1295-1301. [PMID: 35651251 DOI: 10.1021/acsmacrolett.8b00695] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Near-interface alterations in dynamics and glass formation behavior have been the subject of extensive study for the past two decades, both because of their practical importance and in the hope of revealing underlying correlation lengths underpinning glass transition more generally. Here we employ molecular dynamics simulations of thick films to demonstrate that these effects emerge, for segmental-scale translational dynamics at low temperature, from a temperature-independent rescaling of the local activation barrier. This rescaling manifests as a fractional power law decoupling relationship of local dynamics relative to the bulk, with a transition from a regime of weak decoupling at high temperatures to a regime of strong decoupling at low temperatures. The range of this effect saturates at low temperatures, with 90% of the surface perturbation in the barrier lost over a range of 12 segmental diameters. These findings reduce the phenomenology of Tg nanoconfinement effects to two properties-a position-dependent, temperature independent, barrier rescaling factor and an onset time scale-while substantially constraining the predictions required from any theoretical explanation of this phenomenon.
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Affiliation(s)
- Daniel Diaz-Vela
- The University of Akron, 250 South Forge Street, Akron, Ohio 44325, United States
| | - Jui-Hsiang Hung
- The University of Akron, 250 South Forge Street, Akron, Ohio 44325, United States
| | - David S. Simmons
- The University of South Florida, 4202 East Fowler Avenue, ENB 118, Tampa, Florida 33620, United States
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37
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Zhang Y, Woods CN, Alvarez M, Jin Y, Riggleman RA, Fakhraai Z. Effect of substrate interactions on the glass transition and length-scale of correlated dynamics in ultra-thin molecular glass films. J Chem Phys 2018; 149:184902. [PMID: 30441931 DOI: 10.1063/1.5038174] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Interfacial interactions can play an important role in the glass transition temperature (T g ) and relaxation dynamics of ultra-thin glass polymer films. We have recently shown that similar to the polymeric systems in ultra-thin molecular glass films of N, N'-Bis(3-methylphenyl)-N, N'-diphenylbenzidine (TPD), the T g is reduced and dynamics are enhanced. Furthermore, in molecular glass systems, as the film thickness is reduced below ∼30 nm, the dynamics at the two interfaces correlate such that the range of the gradients in the dynamics induced by the free surface narrows compared to thicker films. These observations indicate that the dynamics of the glassy thin films are strongly correlated and cannot be explained by a simple two-layer model consisting of a bulk and a thin interfacial layer with a constant thickness and constant range of dynamical gradients. Here, we investigate the effect of film/substrate interactions on the film dynamics by varying the TPD/substrate interfacial interactions. We show that thin TPD films with thicknesses below ∼60 nm show a smaller extent of T g reduction and enhanced dynamics when supported on a near-neutral substrate (wetting) compared to a weakly interacting (dewetting) substrate. However, the ∼30 nm length scale, where the activation energy significantly reduces from its bulk value as measured by the onset of the glass transition remains unchanged. Coarse-grained molecular dynamics simulation also shows a narrowing in the range of relaxation times once the thickness is sufficiently reduced for the two interfaces to dynamically correlate, consistent with previous work. These results suggest that the length-scale for the correlated dynamics is independent of interfacial interactions and the polymeric nature of the film and may originate from the bulk glass properties.
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Affiliation(s)
- Yue Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Connor N Woods
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Mauricio Alvarez
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Yi Jin
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Robert A Riggleman
- Department of Chemical and Biomolecular 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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38
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Holt AP, Roland CM. Segmental and secondary dynamics of nanoparticle-grafted oligomers. SOFT MATTER 2018; 14:8604-8611. [PMID: 30318533 DOI: 10.1039/c8sm01443d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The local segmental and secondary dynamics of tetramethylene oxide oligomer grafted to silica nanoparticles (NPs) were investigated as a function of grafting density and molecular weight. Grafting slows the segmental (α) dynamics, but gives rise to faster secondary (β) motions. Interestingly, the magnitude of these effects decreases with the extent of grafting (i.e., surface coverage), as well as with oligomer molecular weight. The disparity in dynamical effects reflects the decoupling of the segmental and more local β dynamics, the former is associated with stronger dynamic correlations that extend over a greater spatial range. This results in greater sensitivity to interactions, including tethering of the chains to the NP surface.
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Affiliation(s)
- Adam P Holt
- Chemistry Division, Naval Research Laboratory, Code 6105, Washington, DC 20375-5342, USA.
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39
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White RP, Lipson JEG. Connecting Pressure-Dependent Dynamics to Dynamics under Confinement: The Cooperative Free Volume Model Applied to Poly(4-chlorostyrene) Bulk and Thin Films. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01392] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Ronald P. White
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Jane E. G. Lipson
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
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40
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Katsumata R, Dulaney AR, Kim CB, Ellison CJ. Glass Transition and Self-Diffusion of Unentangled Polymer Melts Nanoconfined by Different Interfaces. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00475] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Reika Katsumata
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Austin R. Dulaney
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Chae Bin Kim
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Christopher J. Ellison
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
- Department of Chemical Engineering and Materials Science, The University of Minnesota - Twin Cities, Minneapolis, Minnesota 55455, United States
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41
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Ma F, Xu B, Song Y, Zheng Q. Influence of molecular weight on molecular dynamics and dynamic rheology of polypropylene glycol filled with silica. RSC Adv 2018; 8:31972-31978. [PMID: 35547494 PMCID: PMC9085909 DOI: 10.1039/c8ra04497j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 08/03/2018] [Indexed: 11/21/2022] Open
Abstract
Molecular weight strongly influences the molecular dynamics and rheological responses of nanocomposites, which is far from being well understood. Herein molecular dynamics and rheological behaviors of hydrophilic fumed silica filled unentangled polypropylene glycol (PPG) were investigated as a function of weight averaged molecular weight (M w) of PPG and volume fraction (∅) of silica. It is shown that M w does not affect the glassy layers surrounding the nanoparticles and the segmental dynamics of the mobile PPG phase. On the other hand, the mobile PPG phase in the highly filled nanocomposites exhibits an abnormal "more fragile" to "stronger" transition with increasing M w. The reinforcement and thinning behaviors are stronger in lower-M w nanocomposites with the "more fragile" mobile PPG phase. The results suggest that reinforcement of nanocomposites affects the dynamic fragility of the mobile phase of the matrix.
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Affiliation(s)
- Furui Ma
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University Hangzhou 310027 China
| | - Bei Xu
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University Hangzhou 310027 China
| | - Yihu Song
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University Hangzhou 310027 China
| | - Qiang Zheng
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University Hangzhou 310027 China
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42
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Cheng Y, Yang J, Hung JH, Patra TK, Simmons DS. Design Rules for Highly Conductive Polymeric Ionic Liquids from Molecular Dynamics Simulations. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00572] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Yizi Cheng
- Department of Polymer Engineering, University of Akron, 250 South Forge St., Akron, Ohio 44325, United States
| | - Junhong Yang
- Department of Polymer Engineering, University of Akron, 250 South Forge St., Akron, Ohio 44325, United States
| | - Jui-Hsiang Hung
- Department of Polymer Engineering, University of Akron, 250 South Forge St., Akron, Ohio 44325, United States
| | - Tarak K. Patra
- Department of Polymer Engineering, University of Akron, 250 South Forge St., Akron, Ohio 44325, United States
| | - David S. Simmons
- Department of Chemical and Biomedical Engineering, University of South Florida, Tampa, Florida 33612, United States
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43
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Lee H, Sethuraman V, Kim Y, Lee W, Ryu DY, Ganesan V. Nonmonotonic Glass Transition Temperature of Polymer Films Supported on Polymer Brushes. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00290] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Hoyeon Lee
- Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Vaidyanathan Sethuraman
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Yeongsik Kim
- Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Wooseop Lee
- Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Du Yeol Ryu
- Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Venkat Ganesan
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
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44
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Christie D, Register RA, Priestley RD. Direct Measurement of the Local Glass Transition in Self-Assembled Copolymers with Nanometer Resolution. ACS CENTRAL SCIENCE 2018; 4:504-511. [PMID: 29721533 PMCID: PMC5920610 DOI: 10.1021/acscentsci.8b00043] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Indexed: 05/07/2023]
Abstract
Nanoscale compositional heterogeneity in block copolymers can impart synergistic property combinations, such as stiffness and toughness. However, until now, there has been no experimental method to locally probe the dynamics at a specific location within these structured materials. Here, this was achieved by incorporating pyrene-bearing monomers at specific locations along the polymer chain, allowing the labeled monomers' local environment to be interrogated via fluorescence. In lamellar-forming poly(butyl methacrylate-b-methyl methacrylate) diblock copolymers, a strong gradient in glass transition temperature, Tg, of the higher-Tg block, 42 K over 4 nm, was mapped with nanometer resolution. These measurements also revealed a strongly asymmetric influence of the domain interface on Tg, with a much smaller dynamic gradient being observed for the lower-Tg block.
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Affiliation(s)
- Dane Christie
- Department
of Chemical and Biological Engineering, Princeton Institute for the Science
and Technology of Materials, Princeton University, Princeton, New Jersey 08544, United States
| | - Richard A. Register
- Department
of Chemical and Biological Engineering, Princeton Institute for the Science
and Technology of Materials, Princeton University, Princeton, New Jersey 08544, United States
- E-mail:
| | - Rodney D. Priestley
- Department
of Chemical and Biological Engineering, Princeton Institute for the Science
and Technology of Materials, Princeton University, Princeton, New Jersey 08544, United States
- E-mail:
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45
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Hung JH, Mangalara JH, Simmons DS. Heterogeneous Rouse Model Predicts Polymer Chain Translational Normal Mode Decoupling. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00135] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Jui-Hsiang Hung
- Department of Polymer Engineering, The University of Akron, 250 South Forge Street, Akron, Ohio 44325-0301, United States
| | - Jayachandra Hari Mangalara
- 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
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46
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Zhang X, Zhao J, Snyder CR, Al‐Enizi A, Eltazahry A, Simmons DS, Karim A. Structure, nanomechanics, and dynamics of dispersed surfactant‐free clay nanocomposite films. POLYM ENG SCI 2018. [DOI: 10.1002/pen.24693] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Xiao Zhang
- Department of Polymer EngineeringUniversity of AkronAkron Ohio44325
| | - Jing Zhao
- Department of Polymer EngineeringUniversity of AkronAkron Ohio44325
- Materials Science and Engineering DivisionNational Institute of Standards and TechnologyGaithersburg Maryland20899
| | - Chad R. Snyder
- Materials Science and Engineering DivisionNational Institute of Standards and TechnologyGaithersburg Maryland20899
| | - Abdullah Al‐Enizi
- Chemistry Department, Faculty of ScienceKing Saud UniversityRiyadh11451 Saudi Arabia
| | - Ahmed Eltazahry
- Materials Science and Technology Program, College of Arts and Sciences, Qatar University, PO Box 2713, Doha, Qatar & Polymer Materials Research Department, Advanced Technology and New Materials Research InstituteCity for Scientific Research and Technology ApplicationsNew Borg El‐Arab City Alexandria Egypt
| | - David S. Simmons
- Department of Polymer EngineeringUniversity of AkronAkron Ohio44325
| | - Alamgir Karim
- Department of Polymer EngineeringUniversity of AkronAkron Ohio44325
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47
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Yang G, Kim K, Wang W, Chen B, Mattoussi H, Hallinan DT. Scaling Laws for Polymer Chains Grafted onto Nanoparticles. MACROMOL CHEM PHYS 2018. [DOI: 10.1002/macp.201700417] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Guang Yang
- Aero‐Propulsion, Mechatronics, and Energy Center Florida State University 2003 Levy Avenue Tallahassee FL 32310 USA
- Chemical and Biomedical Engineering Department FAMU‐FSU College of Engineering 2525 Pottsdamer Street Tallahassee FL 32310 USA
| | - Kyoungmin Kim
- Aero‐Propulsion, Mechatronics, and Energy Center Florida State University 2003 Levy Avenue Tallahassee FL 32310 USA
- Chemical and Biomedical Engineering Department FAMU‐FSU College of Engineering 2525 Pottsdamer Street Tallahassee FL 32310 USA
| | - Wentao Wang
- Chemistry and Biochemistry Department Florida State University 95 Chieftan Way Tallahassee FL 32306‐4390 USA
| | - Banghao Chen
- Chemistry and Biochemistry Department Florida State University 95 Chieftan Way Tallahassee FL 32306‐4390 USA
| | - Hedi Mattoussi
- Chemistry and Biochemistry Department Florida State University 95 Chieftan Way Tallahassee FL 32306‐4390 USA
| | - Daniel T. Hallinan
- Aero‐Propulsion, Mechatronics, and Energy Center Florida State University 2003 Levy Avenue Tallahassee FL 32310 USA
- Chemical and Biomedical Engineering Department FAMU‐FSU College of Engineering 2525 Pottsdamer Street Tallahassee FL 32310 USA
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48
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Kasavan BL, Baglay RR, Roth CB. Local Glass Transition Temperature
T
g
(
z
) Profile in Polystyrene next to Polybutadiene with and without Plasticization Effects. MACROMOL CHEM PHYS 2017. [DOI: 10.1002/macp.201700328] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | | | - Connie B. Roth
- Department of Physics Emory University Atlanta GA 30322 USA
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49
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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
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50
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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]
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