Hierarchical Canopy Dynamics of Electrolyte-Doped Nanoscale Ionic Materials

Handle URI:
http://hdl.handle.net/10754/598456
Title:
Hierarchical Canopy Dynamics of Electrolyte-Doped Nanoscale Ionic Materials
Authors:
Jespersen, Michael L.; Mirau, Peter A.; von Meerwall, Ernst D.; Koerner, Hilmar; Vaia, Richard A.; Fernandes, Nikhil J.; Giannelis, Emmanuel P.
Abstract:
Nanoscale ionic materials (NIMs) are organic-inorganic hybrids prepared from ionically functionalized nanoparticles (NP) neutralized by oligomeric polymer counterions. NIMs are designed to behave as liquids under ambient conditions in the absence of solvent and have no volatile organic content, making them useful for a number of applications. We have used nuclear magnetic resonance relaxation and pulsed-field gradient NMR to probe local and collective canopy dynamics in NIMs based on 18-nm silica NPs with a covalently bound anionic corona, neutralized by amine-terminated ethylene oxide/propylene oxide block copolymers. The NMR relaxation studies show that the nanosecond-scale canopy dynamics depend on the degree of neutralization, the canopy radius of gyration, and crowding at the ionically modified NP surface. Two canopy populations are observed in the diffusion experiments, demonstrating that one fraction of the canopy is bound to the NP surface on the time scale (milliseconds) of the diffusion experiment and is surrounded by a more mobile layer of canopy that is unable to access the surface due to molecular crowding. The introduction of electrolyte ions (Na+ or Mg2+) screens the canopy-corona electrostatic interactions, resulting in a reduced bulk viscosity and faster canopy exchange. The magnitude of the screening effect depends upon ion concentration and valence, providing a simple route for tuning the macroscopic properties of NIMs. © 2013 American Chemical Society.
Citation:
Jespersen ML, Mirau PA, von Meerwall ED, Koerner H, Vaia RA, et al. (2013) Hierarchical Canopy Dynamics of Electrolyte-Doped Nanoscale Ionic Materials. Macromolecules 46: 9669–9675. Available: http://dx.doi.org/10.1021/ma402002a.
Publisher:
American Chemical Society (ACS)
Journal:
Macromolecules
KAUST Grant Number:
KUS-C1-018-02
Issue Date:
23-Dec-2013
DOI:
10.1021/ma402002a
Type:
Article
ISSN:
0024-9297; 1520-5835
Sponsors:
Funding provided by the Air Force Office of Scientific Research is gratefully acknowledged. The diffusion portion of this work was supported by the National Science Foundation under Grant No. DMR 04 55117. This publication is based on work supported by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST). A portion of this research was carried out while M.L.J. was a National Research Council Associate at the Air Force Research Laboratory and an employee of UES, Inc. (Dayton). Jeffamines M-2070 and M-600 were generously donated by Huntsman Corporation (Houston, TX). M. Tchoul contributed GPC in support of this study. The authors would like to thank George Fultz and Timothy Reid (University of Dayton Research Institute) for viscosity and ICP-MS data supporting this research. The authors also thankfully acknowledge Dr. Rajiv J. Berry and Phuong T. Ngo (AFRL/RX) for helpful discussions regarding this work. We would like to thank Dr. Alexander Hexemer and Dr. Eric Schaible for guidance, setup, and data collection at beamline 7.3.3 at the Advanced Light Source/ Lawrence Berkley National Laboratory. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-ACO2-05CH11231.
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Full metadata record

DC FieldValue Language
dc.contributor.authorJespersen, Michael L.en
dc.contributor.authorMirau, Peter A.en
dc.contributor.authorvon Meerwall, Ernst D.en
dc.contributor.authorKoerner, Hilmaren
dc.contributor.authorVaia, Richard A.en
dc.contributor.authorFernandes, Nikhil J.en
dc.contributor.authorGiannelis, Emmanuel P.en
dc.date.accessioned2016-02-25T13:21:02Zen
dc.date.available2016-02-25T13:21:02Zen
dc.date.issued2013-12-23en
dc.identifier.citationJespersen ML, Mirau PA, von Meerwall ED, Koerner H, Vaia RA, et al. (2013) Hierarchical Canopy Dynamics of Electrolyte-Doped Nanoscale Ionic Materials. Macromolecules 46: 9669–9675. Available: http://dx.doi.org/10.1021/ma402002a.en
dc.identifier.issn0024-9297en
dc.identifier.issn1520-5835en
dc.identifier.doi10.1021/ma402002aen
dc.identifier.urihttp://hdl.handle.net/10754/598456en
dc.description.abstractNanoscale ionic materials (NIMs) are organic-inorganic hybrids prepared from ionically functionalized nanoparticles (NP) neutralized by oligomeric polymer counterions. NIMs are designed to behave as liquids under ambient conditions in the absence of solvent and have no volatile organic content, making them useful for a number of applications. We have used nuclear magnetic resonance relaxation and pulsed-field gradient NMR to probe local and collective canopy dynamics in NIMs based on 18-nm silica NPs with a covalently bound anionic corona, neutralized by amine-terminated ethylene oxide/propylene oxide block copolymers. The NMR relaxation studies show that the nanosecond-scale canopy dynamics depend on the degree of neutralization, the canopy radius of gyration, and crowding at the ionically modified NP surface. Two canopy populations are observed in the diffusion experiments, demonstrating that one fraction of the canopy is bound to the NP surface on the time scale (milliseconds) of the diffusion experiment and is surrounded by a more mobile layer of canopy that is unable to access the surface due to molecular crowding. The introduction of electrolyte ions (Na+ or Mg2+) screens the canopy-corona electrostatic interactions, resulting in a reduced bulk viscosity and faster canopy exchange. The magnitude of the screening effect depends upon ion concentration and valence, providing a simple route for tuning the macroscopic properties of NIMs. © 2013 American Chemical Society.en
dc.description.sponsorshipFunding provided by the Air Force Office of Scientific Research is gratefully acknowledged. The diffusion portion of this work was supported by the National Science Foundation under Grant No. DMR 04 55117. This publication is based on work supported by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST). A portion of this research was carried out while M.L.J. was a National Research Council Associate at the Air Force Research Laboratory and an employee of UES, Inc. (Dayton). Jeffamines M-2070 and M-600 were generously donated by Huntsman Corporation (Houston, TX). M. Tchoul contributed GPC in support of this study. The authors would like to thank George Fultz and Timothy Reid (University of Dayton Research Institute) for viscosity and ICP-MS data supporting this research. The authors also thankfully acknowledge Dr. Rajiv J. Berry and Phuong T. Ngo (AFRL/RX) for helpful discussions regarding this work. We would like to thank Dr. Alexander Hexemer and Dr. Eric Schaible for guidance, setup, and data collection at beamline 7.3.3 at the Advanced Light Source/ Lawrence Berkley National Laboratory. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-ACO2-05CH11231.en
dc.publisherAmerican Chemical Society (ACS)en
dc.titleHierarchical Canopy Dynamics of Electrolyte-Doped Nanoscale Ionic Materialsen
dc.typeArticleen
dc.identifier.journalMacromoleculesen
dc.contributor.institutionWright-Patterson AFB, Dayton, United Statesen
dc.contributor.institutionUniversity of Dayton Research Institute, Dayton, United Statesen
dc.contributor.institutionUniversity of Akron, Akron, United Statesen
dc.contributor.institutionCornell University, Ithaca, United Statesen
kaust.grant.numberKUS-C1-018-02en
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