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Please use this identifier to cite or link to this item: http://hdl.handle.net/1813/30470
Title: Canopy Dynamics in Nanoscale Ionic Materials
Authors: Jesperson, M.L.
Mirau, P.A.
Meerwal, R.A.
Vaia, R.A.
Rodriguez, R.
Giannelis, E.P.
Keywords: NUCLEAR-MAGNETIC-RESONANCE
LIQUID-LIKE BEHAVIOR
STUDYING TRANSLATIONAL DIFFUSION
FUNCTIONALIZED CARBON NANOTUBES
ATACTIC POLYPROPYLENE MELTS
MODEL-FREE APPROACH
THERMAL-CONDUCTIVITY
METAL NANOPARTICLES
LIGAND-EXCHANGE
NMR DIFFUSION
Issue Date: 10-Jun-2010
Publisher: American Chemical Society
Citation: ACS Nano, 2010, 4 (7), pp 3735–3742
Abstract: Nanoscale ionic materials (NIMS) are organic inorganic hybrids in which a core nanostructure is functionalized with a covalently attached corona and an ionically tethered organic canopy. NIMS are engineered to be liquids under ambient conditions in the absence of solvent and are of interest for a variety of applications. We have used nuclear magnetic resonance (NMR) relaxation and pulse-field gradient (PFG) diffusion experiments to measure the canopy dynamics of NIMS prepared from 18-nm silica cores modified by an alkylsilane monolayer possessing terminal sulfonic acid functionality, paired with an amine-terminated ethylene oxide/propylene oxide block copolymer canopy. Carbon NMR studies show that the block copolymer canopy is mobile both in the bulk and in the NIMS and that the fast (ns) dynamics are insensitive to the presence of the silica nanoparticles. Canopy diffusion in the NIMS is slowed relative to the neat canopy, but not to the degree predicted from the diffusion of hard-sphere particles. Canopy diffusion is not restricted to the surface of the nanoparticles and shows unexpected behavior upon addition of excess canopy. Taken together, these data indicate that the liquid-like behavior in NIMS is due to rapid exchange of the block copolymer canopy between the ionically modified nanoparticles.
Related Version: http://pubs.acs.org/doi/pdf/10.1021/nn100112h
URI: http://hdl.handle.net/1813/30470
ISSN: 1936-0851
Appears in Collections:Energy and Sustainability Publications

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