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Mei H, Mahalik JP, Lee D, Laws TS, Terlier T, Stein GE, Kumar R, Verduzco R. Understanding interfacial segregation in polymer blend films with random and mixed side chain bottlebrush copolymer additives. SOFT MATTER 2021; 17:9028-9039. [PMID: 34523659 DOI: 10.1039/d1sm01146d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Bottlebrush polymers are complex macromolecules with tunable physical properties dependent on the chemistry and architecture of both the side chains and the backbone. Prior work has demonstrated that bottlebrush polymer additives can be used to control the interfacial properties of blends with linear polymers but has not specifically addressed the effects of bottlebrush side chain microstructures. Here, using a combination of experiments and self-consistent field theory (SCFT) simulations, we investigated the effects of side chain microstructures by comparing the segregation of bottlebrush additives having random copolymer side chains with bottlebrush additives having a mixture of two different homopolymer side chain chemistries. Specifically, we synthesized bottlebrush polymers with either poly(styrene-ran-methyl methacrylate) side chains or with a mixture of polystyrene (PS) and poly(methyl methacrylate) (PMMA) side chains. The bottlebrush additives were matched in terms of PS and PMMA compositions, and they were blended with linear PS or PMMA chains that ranged in length from shorter to longer than the bottlebrush side chains. Experiments revealed similar behaviors of the two types of bottlebrushes, with a slight preference for mixed side-chain bottlebrushes at the film surface. SCFT simulations were qualitatively consistent with experimental observations, predicting only slight differences in the segregation of bottlebrush additives driven by side chain microstructures. Specifically, these slight differences were driven by the chemistries of the bottlebrush polymer joints and side chain end-groups, which were entropically repelled and attracted to interfaces, respectively. Using SCFT, we also demonstrated that the interfacial behaviors were dominated by entropic effects with high molecular weight linear polymers, leading to enrichment of bottlebrush near interfaces. Surprisingly, the SCFT simulations showed that the chemistry of the joints connecting the bottlebrush backbones and side chains played a more significant role compared with the side chain end groups in affecting differences in surface excess of bottlebrushes with random and mixed side chains. This work provides new insights into the effects of side chain microstructure on segregation of bottlebrush polymer additives.
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Affiliation(s)
- Hao Mei
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005, USA.
| | - Jyoti P Mahalik
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA 01003, USA
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
| | - Dongjoo Lee
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005, USA.
| | - Travis S Laws
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - Tanguy Terlier
- SIMS Lab, Shared Equipment Authority, Rice University, Houston, TX 77005, USA
| | - Gila E Stein
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - Rajeev Kumar
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
| | - Rafael Verduzco
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005, USA.
- Materials Science and NanoEngineering, Rice University, Houston, TX 77005, USA
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2
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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: 17] [Impact Index Per Article: 5.7] [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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3
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Mei H, Laws TS, Mahalik JP, Li J, Mah AH, Terlier T, Bonnesen P, Uhrig D, Kumar R, Stein GE, Verduzco R. Entropy and Enthalpy Mediated Segregation of Bottlebrush Copolymers to Interfaces. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01801] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
| | | | - Jyoti P. Mahalik
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | | | - Adeline H. Mah
- Materials Science and Engineering Program, University of Houston, Houston, Texas 77204, United States
| | | | - Peter Bonnesen
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - David Uhrig
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Rajeev Kumar
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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4
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Yang F, Presto D, Pan Y, Liu K, Zhou L, Narayanan S, Zhu Y, Peng Z, Soucek MD, Tsige M, Foster MD. Proximity to Graphene Dramatically Alters Polymer Dynamics. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00317] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
| | | | | | | | | | - Suresh Narayanan
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
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5
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Thees MF, Roth CB. Unexpected Molecular Weight Dependence to the Physical Aging of Thin Polystyrene Films Present at Ultra‐High Molecular Weights. ACTA ACUST UNITED AC 2019. [DOI: 10.1002/polb.24797] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [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 Georgia 30322
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6
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Zhang F, Quirk RP, Gerislioglu S, Wesdemiotis C, Bekele S, Tsige M, Koh YP, Simon SL, Foster MD. Synthesis and Characterization of Well-Defined, Tadpole-Shaped Polystyrene with a Single Atom Junction Point. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01384] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | | | | | - Yung P. Koh
- Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, United States
| | - Sindee L. Simon
- Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, United States
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7
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Zhang F, He Q, Zhou Y, Narayanan S, Wang C, Vogt BD, Foster MD. Anomalous Confinement Slows Surface Fluctuations of Star Polymer Melt Films. ACS Macro Lett 2018; 7:834-839. [PMID: 35650756 DOI: 10.1021/acsmacrolett.8b00278] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The unusually large film thickness at which confinement effects manifest themselves in surface fluctuations of unentangled four-arm star polymers has been defined using film thicknesses from 10Rg to 107Rg. For 15k four-arm star polystyrene (SPS), confinement appears at a thickness between 112 nm (40Rg) and 72 nm (26Rg), which is remarkably larger than the thicknesses at which confinement appears for unentangled 6k linear (<15 nm, <7Rg) and 6k and 14k cyclic (24 and 22 nm, respectively) polystyrenes. Data for 15k star films can be rationalized using a two-layer model with a 17 nm (6Rg) thick highly viscous layer at the substrate, which is significantly thicker than the 1Rg thick "irreversibly adsorbed" layer. For a 29 nm (10Rg) thick film, more striking confinement occurs due to the combined influence of both interfaces. These results underscore the extraordinary role long-chain branching plays in dictating surface fluctuations of thin films.
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Affiliation(s)
| | | | | | - Suresh Narayanan
- X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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Glynos E, Johnson KJ, Frieberg B, Chremos A, Narayanan S, Sakellariou G, Green PF. Free Surface Relaxations of Star-Shaped Polymer Films. PHYSICAL REVIEW LETTERS 2017; 119:227801. [PMID: 29286814 PMCID: PMC5839106 DOI: 10.1103/physrevlett.119.227801] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Indexed: 06/07/2023]
Abstract
The surface relaxation dynamics of supported star-shaped polymer thin films are shown to be slower than the bulk, persisting up to temperatures at least 50 K above the bulk glass transition temperature T_{g}^{bulk}. This behavior, exhibited by star-shaped polystyrenes with functionality f=8 arms and molecular weights per arm M_{arm}
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Affiliation(s)
- Emmanouil Glynos
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, P.O. Box 1385, 711 10 Heraklion, Crete, Greece
| | - Kyle J. Johnson
- Department of Material Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
- Biointeraces Institute, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Bradley Frieberg
- Biointeraces Institute, University of Michigan, Ann Arbor, Michigan 48109, USA
- Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Alexandros Chremos
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Suresh Narayanan
- Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografou, 15771, Athens Greece
| | | | - Peter F. Green
- Department of Material Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
- Biointeraces Institute, University of Michigan, Ann Arbor, Michigan 48109, USA
- Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
- National Renewable Energy Laboratory (NREL), Golden, Colorado 80401, USA
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9
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Zhou Y, He Q, Zhang F, Yang F, Narayanan S, Yuan G, Dhinojwala A, Foster MD. Modifying Surface Fluctuations of Polymer Melt Films with Substrate Modification. ACS Macro Lett 2017; 6:915-919. [PMID: 35650890 DOI: 10.1021/acsmacrolett.7b00459] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Deposition of a plasma polymerized film on a silicon substrate substantially changes the fluctuations on the surface of a sufficiently thin melt polystyrene (PS) film atop the substrate. Surface fluctuation relaxation times measured with X-ray photon correlation spectroscopy (XPCS) for ca. 4Rg thick melt films of 131 kg/mol linear PS on hydrogen-passivated silicon (H-Si) and on a plasma polymer modified silicon wafer can both be described using a hydrodynamic continuum theory (HCT) that assumes the film is characterized throughout its depth by the bulk viscosity. However, when the film thickness is reduced to ∼3Rg, confinement effects are evident. The surface fluctuations are slower than predicted using the HCT, and the confinement effect for the PS on H-Si is larger than that for the PS on the plasma polymerized film. This deviation is due to a difference in the thicknesses of the strongly adsorbed layers at the substrate which are impacted by the substrate surface energy.
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Affiliation(s)
- Yang Zhou
- Department
of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
| | - Qiming He
- Department
of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
| | - Fan Zhang
- Department
of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
| | - Feipeng Yang
- Department
of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
| | - Suresh Narayanan
- X-ray
Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Guangcui Yuan
- Center
for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Ali Dhinojwala
- Department
of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
| | - Mark D. Foster
- Department
of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
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10
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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: 244] [Impact Index Per Article: 34.9] [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.
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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
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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
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12
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He Q, Narayanan S, Wu DT, Foster MD. Confinement Effects with Molten Thin Cyclic Polystyrene Films. ACS Macro Lett 2016; 5:999-1003. [PMID: 35614649 DOI: 10.1021/acsmacrolett.6b00497] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The surface fluctuations of a melt film of a low molecular weight cyclic polystyrene (CPS) manifest confinement effects for a film thickness (14Rg) much larger than that for which a melt film of the linear chain analog manifests confinement. This is true both in terms of absolute thickness and thickness relative to chain size, Rg. In fact, the linear analog polymer does not manifest confinement effects even at a thickness of 7Rg. Both types of films have a strongly adsorbed layer at the substrate that plays a role in slowing the surface fluctuations for the thinnest films. This layer is 70% thicker for the cyclic chains than for the linear chains. At the interface with the substrate the packing of the cyclic chains is perturbed much more strongly than is the packing of the linear chains.
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Affiliation(s)
- Qiming He
- Department
of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
| | - Suresh Narayanan
- X-ray
Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - David T. Wu
- Chemical
Engineering and Chemistry Departments, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Mark D. Foster
- Department
of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
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Johnson KJ, Glynos E, Sakellariou G, Green P. Dynamics of Star-Shaped Polystyrene Molecules: From Arm Retraction to Cooperativity. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00456] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
| | | | - Georgios Sakellariou
- Department
of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis,
Zografou, 15771 Athens, Greece
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14
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Zhang L, Elupula R, Grayson SM, Torkelson JM. Major Impact of Cyclic Chain Topology on the Tg-Confinement Effect of Supported Thin Films of Polystyrene. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b02474] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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
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Shpyrko OG. X-ray photon correlation spectroscopy. JOURNAL OF SYNCHROTRON RADIATION 2014; 21:1057-64. [PMID: 25177994 DOI: 10.1107/s1600577514018232] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 08/08/2014] [Indexed: 05/20/2023]
Abstract
In recent years, X-ray photon correlation spectroscopy (XPCS) has emerged as one of the key probes of slow nanoscale fluctuations, applicable to a wide range of condensed matter and materials systems. This article briefly reviews the basic principles of XPCS as well as some of its recent applications, and discusses some novel approaches to XPCS analysis. It concludes with a discussion of the future impact of diffraction-limited storage rings on new types of XPCS experiments, pushing the temporal resolution to nanosecond and possibly even picosecond time scales.
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Affiliation(s)
- Oleg G Shpyrko
- Department of Physics, University of California San Diego, 9500 Gilman Drive, Mail Code 0319, La Jolla, CA 92093-0319, USA
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Mitra I, Li X, Pesek SL, Makarenko B, Lokitz BS, Uhrig D, Ankner JF, Verduzco R, Stein GE. Thin Film Phase Behavior of Bottlebrush/Linear Polymer Blends. Macromolecules 2014. [DOI: 10.1021/ma501070w] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
| | - Xianyu Li
- Department of Chemical and Biomolecular
Engineering, Rice University, Houston, Texas 77005, United States
| | - Stacy L. Pesek
- Department of Chemical and Biomolecular
Engineering, Rice University, Houston, Texas 77005, United States
| | | | | | | | | | - Rafael Verduzco
- Department of Chemical and Biomolecular
Engineering, Rice University, Houston, Texas 77005, United States
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