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Mirzaalipour A, Aghamohammadi E, Vakili H, Khodabakhsh M, Unal U, Makki H. Molecular Insight into the Effect of Polymer Topology on Wettability of Block Copolymers: The Case of Amphiphilic Polyurethanes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:62-71. [PMID: 38100712 PMCID: PMC10786039 DOI: 10.1021/acs.langmuir.3c01646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 11/09/2023] [Accepted: 11/29/2023] [Indexed: 12/17/2023]
Abstract
The microstructure design of multiblock copolymers is essential for achieving desired interfacial properties in submerged applications. Two major design factors are the chemical composition and polymer topology. Despite a clear relationship between chemical composition and wetting, the effect of polymer topology (i.e., linear vs cross-linked polymers) is not very clear. Thus, in this study, we shed light on the molecular origins of polymer topology on the wetting behavior. To this end, we synthesized linear and three-dimensional (3D) cross-linked network topologies of poly(ethylene glycol) (PEG)-modified polycarbonate polyurethanes with the same amount of hydrophilic PEG groups on the surface (confirmed by X-ray photoelectron spectroscopy (XPS)) and studied the wetting mechanisms through water contact angle (WCA), atomic force microscopy (AFM), and molecular dynamics (MD) simulations. The linear topology exhibited superhydrophilic behavior, while the WCA of the cross-linked polymer was around 50°. AFM analysis (performed on dry and wet samples) suggests that PEG migration toward the interface is the dominant factor. MD simulations confirm the AFM results and unravel the mechanisms: the higher flexibility of PEG in linear topology results in a greater PEG migration to the interface and formation of a thicker interfacial layer (i.e., twice as thick as the cross-linked polymers). Accordingly, water diffusion into the interfacial layer was greater in the case of the linear polymer, leading to better screening of the underneath hydrophobic (polycarbonate) segments.
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Affiliation(s)
- Alireza Mirzaalipour
- Department
of Polymer and Color Engineering, Amirkabir
University of Technology, 424 Hafez Ave., 159163-4311 Tehran, Iran
| | - Elnaz Aghamohammadi
- Department
of Polymer and Color Engineering, Amirkabir
University of Technology, 424 Hafez Ave., 159163-4311 Tehran, Iran
| | - Helma Vakili
- Polymer
Engineering group, School of Chemical Engineering, College of Engineering, University of Tehran, 1417935840 Tehran, Iran
| | | | - Ugur Unal
- Chemistry
Department, Koc University, Rumelifeneri Yolu, Sariyer 34450 Istanbul, Turkey
- Koc
University Surface Science and Technology Center (KUYTAM), Koc University, Rumelifeneri Yolu, Sariyer 34450 Istanbul, Turkey
| | - Hesam Makki
- Department
of Chemistry and Materials Innovation Factory, University of Liverpool, Liverpool L69 7ZD, U.K.
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2
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Chytrosz-Wrobel P, Golda-Cepa M, Drozdz K, Rysz J, Kubisiak P, Kulig W, Brzychczy-Wloch M, Cwiklik L, Kotarba A. In Vitro and In Silico Studies of Functionalized Polyurethane Surfaces toward Understanding Biologically Relevant Interactions. ACS Biomater Sci Eng 2023; 9:6112-6122. [PMID: 37909715 PMCID: PMC10646850 DOI: 10.1021/acsbiomaterials.3c01367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 10/18/2023] [Indexed: 11/03/2023]
Abstract
The solid-aqueous boundary formed upon biomaterial implantation provides a playground for most biochemical reactions and physiological processes involved in implant-host interactions. Therefore, for biomaterial development, optimization, and application, it is essential to understand the biomaterial-water interface in depth. In this study, oxygen plasma-functionalized polyurethane surfaces that can be successfully utilized in contact with the tissue of the respiratory system were prepared and investigated. Through experiments, the influence of plasma treatment on the physicochemical properties of polyurethane was investigated by atomic force microscopy, attenuated total reflection infrared spectroscopy, differential thermal analysis, X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and contact angle measurements, supplemented with biological tests using the A549 cell line and two bacteria strains (Staphylococcus aureus and Pseudomonas aeruginosa). The molecular interpretation of the experimental findings was achieved by molecular dynamics simulations employing newly developed, fully atomistic models of unmodified and plasma-functionalized polyurethane materials to characterize the polyurethane-water interfaces at the nanoscale in detail. The experimentally obtained polar and dispersive surface free energies were consistent with the calculated free energies, verifying the adequacy of the developed models. A 20% substitution of the polymeric chain termini by their oxidized variants was observed in the experimentally obtained plasma-modified polyurethane surface, indicating the surface saturation with oxygen-containing functional groups.
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Affiliation(s)
- Paulina Chytrosz-Wrobel
- Faculty
of Chemistry, Jagiellonian University in
Krakow, Gronostajowa 2, 30-387 Krakow, Poland
| | - Monika Golda-Cepa
- Faculty
of Chemistry, Jagiellonian University in
Krakow, Gronostajowa 2, 30-387 Krakow, Poland
| | - Kamil Drozdz
- Department
of Molecular Medical Microbiology, Chair of Microbiology, Faculty
of Medicine, Jagiellonian University Medical
College, Czysta 18, 31-121 Krakow, Poland
| | - Jakub Rysz
- Faculty
of Physics Astronomy and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
| | - Piotr Kubisiak
- Faculty
of Chemistry, Jagiellonian University in
Krakow, Gronostajowa 2, 30-387 Krakow, Poland
| | - Waldemar Kulig
- Department
of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Monika Brzychczy-Wloch
- Department
of Molecular Medical Microbiology, Chair of Microbiology, Faculty
of Medicine, Jagiellonian University Medical
College, Czysta 18, 31-121 Krakow, Poland
| | - Lukasz Cwiklik
- J.
Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Andrzej Kotarba
- Faculty
of Chemistry, Jagiellonian University in
Krakow, Gronostajowa 2, 30-387 Krakow, Poland
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3
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Nguyen L, Xu LC, Yeager E, Weiss WJ, Siedlecki CA. In vitro evaluation of blood plasma coagulation responses to four medical-grade polyurethane polymers. J Biomater Appl 2023; 38:302-310. [PMID: 37470381 PMCID: PMC10408244 DOI: 10.1177/08853282231191410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
Segmented polyurethane (PU) block copolymers are widely used in implantable cardiovascular medical devices due to their good biocompatibility and excellent mechanical properties. More specifically, PU Biospan MS/0.4 was used in ventricular assist devices over the past decades. However, this product is being discontinued and it has become necessary to find an alternative PU biomaterial for application in cardiovascular devices. One important criterion for assessing cardiac biomaterials is blood compatibility. In this study, we characterized the surface properties of four medical-grade PU biomaterials: Biospan MS/0.4, BioSpan S, BioSpan 2F, and CarboSil 20 80A, including surface chemistry, topography, microphase separation structure and wettability, and then measured the blood plasma coagulation responses using bovine and human blood plasma. Results showed that BioSpan 2F contains high amounts of fluorine and has the lowest surface free energy while the other materials have surfaces with silicone present. An in vitro coagulation assay shows that these materials demonstrated improved blood coagulation responses compared to the polystyrene control and there were no significant differences in coagulation time among all PU biomaterials. The chromogenic assay showed all PU materials led to low FXII contact activation, and there were no significant differences in FXII contact activation, consistent with plasma coagulation responses.
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Affiliation(s)
- Lan Nguyen
- Department of Biochemistry and Molecular Biology, Gettysburg College, Gettysburg, PA, USA
| | - Li-Chong Xu
- Department of Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA, USA
| | - Eric Yeager
- Department of Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA, USA
| | - William J Weiss
- Department of Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, College of Medicine, Hershey, PA, USA
| | - Christopher A Siedlecki
- Department of Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, College of Medicine, Hershey, PA, USA
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4
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Xu LC, Chen C, Zhu J, Tang M, Chen A, Allcock HR, Siedlecki CA. New cross-linkable poly[bis(octafluoropentoxy) phosphazene] biomaterials: Synthesis, surface characterization, bacterial adhesion, and plasma coagulation responses. J Biomed Mater Res B Appl Biomater 2020; 108:3250-3260. [PMID: 32558200 PMCID: PMC9427203 DOI: 10.1002/jbm.b.34662] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 04/13/2020] [Accepted: 05/19/2020] [Indexed: 12/20/2022]
Abstract
Biomaterial-associated microbial infection and thrombosis represent major issues to the success of long-term use of implantable blood-contacting medical devices. The development of new poly[bis(octafluoropentoxy) phosphazene (OFP) biomaterials provides new routes for combatting microbial infection and thrombosis. However, the limited mechanical properties of OFP to date render them unsuitable for application in medical devices and inhibit any attempts at subsequent surface topography modification. In this study, we synthesized cross-linkable OFPs (X-OFPs) with the different degrees of cross-linking in an effort to improve the mechanical properties. The results showed that the surface chemistry and surface topography of X-OFPs do not change significantly, but the surface mechanical stiffness increased after cross-linking. Atomic force microscopic phase images showed that the polymer phase separation structures changed due to cross-linking. Experiments with three bacterial strains: Staphylococcal epidermidis, Staphylococcal aureus, and Pseudomonas aeruginosa showed that bacterial adhesion was significantly decreased on the OFP and X-OFPs for both the pre-cross-linked and cross-linked as compared to polyurethane biomaterials. Furthermore, bacterial adhesions were lower on X-OFP surfaces than on pre-cross-linked materials, suggesting that mechanical stiffness is an important parameter influencing bacterial adhesion. Blood plasma coagulation responses revealed longer coagulation times for OFP and X-OFP materials than on polyurethanes, indicating that the new cross-linked OFPs are resistant to plasma coagulation compared to currently used polyurethane biomaterials.
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Affiliation(s)
- Li-Chong Xu
- Department of Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA 17033, United States
| | - Chen Chen
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
| | - Jieru Zhu
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
| | - Meixian Tang
- Department of Biomedical Engineering, The Pennsylvania State University, College of Medicine, Hershey, PA 17033, United States
| | - Andy Chen
- Hershey High School, Hershey, PA 17033, United States
| | - Harry R. Allcock
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
| | - Christopher A. Siedlecki
- Department of Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA 17033, United States
- Department of Biomedical Engineering, The Pennsylvania State University, College of Medicine, Hershey, PA 17033, United States
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5
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Wo Y, Xu LC, Li Z, Matzger AJ, Meyerhoff ME, Siedlecki CA. Antimicrobial nitric oxide releasing surfaces based on S-nitroso-N-acetylpenicillamine impregnated polymers combined with submicron-textured surface topography. Biomater Sci 2017; 5:1265-1278. [PMID: 28560367 PMCID: PMC6290899 DOI: 10.1039/c7bm00108h] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A novel dual functioning antimicrobial CarboSil 20 80A polymer material that combines physical topographical surface modification and nitric oxide (NO) release is prepared and evaluated for its efficacy in reducing bacterial adhesion in vitro. The new biomaterial is created via a soft lithography two-stage replication process to induce submicron textures on its surface, followed by solvent impregnation with the NO donor, S-nitroso-N-acetylpenicillamine (SNAP), to obtain long-term (up to 38 d) NO release. The NO releasing textured polymer surface is evaluated against four bacteria commonly known to cause infections in hospital settings and the results demonstrate that the combined strategy enables a synergistic effect on reducing the bacterial adhesion of Staphylococcus epidermidis and Pseudomonas aeruginosa bacteria.
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Affiliation(s)
- Yaqi Wo
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Li-Chong Xu
- Department of Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Zi Li
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Adam J. Matzger
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Mark E. Meyerhoff
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Christopher A. Siedlecki
- Department of Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
- Department of Bioengineering, The Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
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Wo Y, Brisbois EJ, Bartlett RH, Meyerhoff ME. Recent advances in thromboresistant and antimicrobial polymers for biomedical applications: just say yes to nitric oxide (NO). Biomater Sci 2016; 4:1161-83. [PMID: 27226170 PMCID: PMC4955746 DOI: 10.1039/c6bm00271d] [Citation(s) in RCA: 170] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Biomedical devices are essential for patient diagnosis and treatment; however, when blood comes in contact with foreign surfaces or homeostasis is disrupted, complications including thrombus formation and bacterial infections can interrupt device functionality, causing false readings and/or shorten device lifetime. Here, we review some of the current approaches for developing antithrombotic and antibacterial materials for biomedical applications. Special emphasis is given to materials that release or generate low levels of nitric oxide (NO). Nitric oxide is an endogenous gas molecule that can inhibit platelet activation as well as bacterial proliferation and adhesion. Various NO delivery vehicles have been developed to improve NO's therapeutic potential. In this review, we provide a summary of the NO releasing and NO generating polymeric materials developed to date, with a focus on the chemistry of different NO donors, the polymer preparation processes, and in vitro and in vivo applications of the two most promising types of NO donors studied thus far, N-diazeniumdiolates (NONOates) and S-nitrosothiols (RSNOs).
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Affiliation(s)
- Yaqi Wo
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
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Xu LC, Bauer JW, Siedlecki CA. Proteins, platelets, and blood coagulation at biomaterial interfaces. Colloids Surf B Biointerfaces 2014; 124:49-68. [PMID: 25448722 PMCID: PMC5001692 DOI: 10.1016/j.colsurfb.2014.09.040] [Citation(s) in RCA: 248] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/15/2014] [Accepted: 09/18/2014] [Indexed: 12/24/2022]
Abstract
Blood coagulation and platelet adhesion remain major impediments to the use of biomaterials in implantable medical devices. There is still significant controversy and question in the field regarding the role that surfaces play in this process. This manuscript addresses this topic area and reports on state of the art in the field. Particular emphasis is placed on the subject of surface engineering and surface measurements that allow for control and observation of surface-mediated biological responses in blood and test solutions. Appropriate use of surface texturing and chemical patterning methodologies allow for reduction of both blood coagulation and platelet adhesion, and new methods of surface interrogation at high resolution allow for measurement of the relevant biological factors.
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Affiliation(s)
- Li-Chong Xu
- Department of Surgery, Biomedical Engineering Institute, The Pennsylvania State University, College of Medicine, Hershey, PA 17033, United States
| | - James W Bauer
- Department of Bioengineering, Biomedical Engineering Institute, The Pennsylvania State University, College of Medicine, Hershey, PA 17033, United States
| | - Christopher A Siedlecki
- Department of Surgery, Biomedical Engineering Institute, The Pennsylvania State University, College of Medicine, Hershey, PA 17033, United States; Department of Bioengineering, Biomedical Engineering Institute, The Pennsylvania State University, College of Medicine, Hershey, PA 17033, United States.
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8
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Nair SS, McCullough EJ, Yadavalli VK, Wynne KJ. Integrated compositional and nanomechanical analysis of a polyurethane surface modified with a fluorous oxetane siliceous-network hybrid. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:12986-12995. [PMID: 25268217 DOI: 10.1021/la503216h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Investigating the surface characteristics of heterogeneous polymer systems is important for understanding how to better tailor surfaces and engineering specific reactions and desirable properties. Here we report on the surface properties for a blend consisting of a major component, a linear polyurethane or thermoplastic elastomer (TPU), and a minor component that is a hybrid network. The hybrid network consists of a fluorous polyoxetane soft block and a hydrolysis/condensation inorganic (HyCoin) network. Phase separation during coating formation results in surface concentration of the minor fluorous hybrid domain. The TPU is H12MDI/BD(50)-PTMO-1000 derived from bis(cyclohexylmethylene)-diisocyanate and butane diol (50 wt %) and poly(tetramethylene oxide). Surface modification results from a novel network-forming hybrid composed of poly(trifluoroethoxymethyl-methyl oxetane) diol) (3F) as the fluorous moiety end-capped with 3-isocyanatopropylriethoxysilane and bis(triethoxysilyl)ethane (BTESE) as a siliceous stabilizer. We use an integrated approach that combines elemental analysis of the near surface via X-ray photoelectron microscopy with surface mapping using atomic force microscopy that presents topographical and phase imaging along with nanomechanical properties. Overall, this versatile, high-resolution approach enabled unique insight into surface composition and morphology that led to a model of heterogeneous surfaces containing a range of constituents and properties.
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Affiliation(s)
- Sithara S Nair
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University 601 West Main Street, Richmond, Virginia 23284, United States
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Xu LC, Siedlecki CA. Staphylococcus epidermidis
adhesion on hydrophobic and hydrophilic textured biomaterial surfaces. Biomed Mater 2014; 9:035003. [DOI: 10.1088/1748-6041/9/3/035003] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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10
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Andriani Y, Morrow IC, Taran E, Edwards GA, Schiller TL, Osman AF, Martin DJ. In vitro biostability of poly(dimethyl siloxane/hexamethylene oxide)-based polyurethane/layered silicate nanocomposites. Acta Biomater 2013; 9:8308-17. [PMID: 23727246 DOI: 10.1016/j.actbio.2013.05.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 05/02/2013] [Accepted: 05/22/2013] [Indexed: 10/26/2022]
Abstract
We have prepared a number of silicone-based thermoplastic polyurethane (TPU) nanocomposites and demonstrated an enhancement of in vitro biostability against metal-ion-induced oxidation for potential use in long-term implantable medical devices. Organoclays based on both low-aspect-ratio hectorites and high-aspect-ratio fluoromicas were evaluated after being dual-modified with two quaternary alkyl ammonium salts with differing degrees of polarity. The resultant nanocomposites were tested for in vitro biostability using physiologically relevant oxidizing conditions. Subsequently, the effects of oxidative treatment on the surface degradation and bulk mechanical integrity of the nanocomposites were investigated and compared with the parent TPUs to identify nanocomposites with the most desirable features for long-term implantation. Here, we demonstrate that the low-aspect-ratio organohectorite was delaminated and well dispersed in the nanocomposites. Importantly, these factors gave rise to the enhanced oxidative stability. In addition, the mechanical properties of all nanocomposites were less adversely affected by the oxidative treatment compared to their parent TPUs. These results suggest the potential for improved mechanical integrity and biostability when suitable dual modified organoclays are incorporated in a silicone-based TPU.
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Xu LC, Runt J, Siedlecki CA. Dynamics of hydrated polyurethane biomaterials: Surface microphase restructuring, protein activity and platelet adhesion. Acta Biomater 2010; 6:1938-47. [PMID: 19948255 DOI: 10.1016/j.actbio.2009.11.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 10/19/2009] [Accepted: 11/23/2009] [Indexed: 11/26/2022]
Abstract
Microphase separation is a central feature of segmented polyurethane biomaterials and contributes to the biological response to these materials. In this study we utilized atomic force microscopy (AFM) to study the dynamic restructuring of three polyurethanes having soft segment chemistries of interest in biomedical applications. For each of the materials we followed the changes in near surface mechanical properties during hydration, as well as fibrinogen activity and platelet adhesion on these surfaces. Both AFM phase imaging and force mode analysis demonstrated that these polyurethane biomaterials underwent reorientation and rearrangement resulting in a net enrichment of hard domains at the surface. Fibrinogen activity and platelet adhesion on the polyurethane surfaces were found to decrease with increasing hydration time. The findings suggest that water-induced enrichment of hydrophilic hard domains at the surface changes the local surface physical and chemical properties in a way that influences the conformation of fibrinogen, changing the availability of the platelet-binding sites in the protein. This work demonstrates that the hydrated polyurethane biomaterial interface is a complex and dynamic environment where the surface chemistry is changing, altering the activity of fibrinogen and affecting blood platelet adhesion.
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12
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Xu LC, Siedlecki CA. Microphase separation structure influences protein interactions with poly(urethane urea) surfaces. J Biomed Mater Res A 2010; 92:126-36. [DOI: 10.1002/jbm.a.32340] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Waletzko RS, Korley LTJ, Pate BD, Thomas EL, Hammond PT. Role of Increased Crystallinity in Deformation-Induced Structure of Segmented Thermoplastic Polyurethane Elastomers with PEO and PEO−PPO−PEO Soft Segments and HDI Hard Segments. Macromolecules 2009. [DOI: 10.1021/ma8022052] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ryan S. Waletzko
- Department of Chemical Engineering, Department of Materials Science and Engineering, and Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - LaShanda T. James Korley
- Department of Chemical Engineering, Department of Materials Science and Engineering, and Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Brian D. Pate
- Department of Chemical Engineering, Department of Materials Science and Engineering, and Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Edwin L. Thomas
- Department of Chemical Engineering, Department of Materials Science and Engineering, and Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Paula T. Hammond
- Department of Chemical Engineering, Department of Materials Science and Engineering, and Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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