Nuclear Magnetic Resonance (NMR) Spectroscopy Facility
The Sandia National
Laboratories NMR Spectroscopy Facility maintains both high resolution solution and
solid state capabilities for the characterization of chemical structure,
reaction kinetics, morphologies and dynamic properties for a wide range of
materials. Our research includes the development and implementation of both multi-frequency and multi-dimensional NMR experiments to probe specific chemical or materials science related questions.
Graphene/Liquid Crystal Materials
NMR provides the perfect tool to measure the properties of graphene related materials. Our efforts include the development of HRMAS NMR diffusometry in nanoporous carbons and 2H NMR studies of orientational order in LC composites.
Precise manipulation of structure within ionomer and fuel call membranes continues to be an area of interest. In collaboration with University of Pennsylvania a series of poly(ethylene-co-acrylic acid) copolymers P(E-AA) have been prepared to address the role of carboxylic acid spacing.Utilizing samples with precise versus random placement of the pendant carboxylic acid group, the effect on structure, morphology, and dynamics is being investigated. Solid state 1H and 13C MAS NMR spectroscopy is being used to characterize these changes. The NMR reveals that the changes in the P(E-AA) structure and dynamics imposed by these carboxylic acid defects are distinct, and vary with temperature and the degree of Zn2+, Li+ or Na+ neutralization. These results are being combined with ab initio calculations of NMR shielding parameters to understand the experimental results.
C. Francisco Buitrago, Janelle E. Jenkins, Kathleen L. Opper, Brian S. Aitken, Kenneth B. Wagener, Todd M. Alam, and Karen I. Winey, “Room Temperature Morphologies of Precise Acid- and Ion-Containing Polyethylenes”, Macromolecules, ASAP (2013). http:/dx/doi.org/10.1021/ma4013169
C. Francisco Buitrago, Todd M. Alam, Kathleen L. Opper, Brian S. Aitken, Kenneth B. Wagener, and Karen I. Winey, “Morphological Trends in Precise Acid- and Ion-Containing Polyethylenes at Elevated Temperature”, Macromolecules, ASAP (2013). http:/dx/doi.org/10.1021/ma4013175
Todd M. Alam, Janelle E. Jenkins, Dan S. Bolinitineanu, Mark J. Stevens, Amalie L. Frischknecht, C. Francisco Buitrago, Karen I. Winey, Kathleen L. Opper and Kenneth B. Wagener, “Heterogeneous Coordination Environments in Lithium-Neutralized Ionomers Identified Using 1H and 7Li MAS NMR”, Materials, 5, 1508-1527 (2012). http://www.mdpi.com/1996-1944/5/8/1508___________________________________________________________
Structure and Dynamics in Inorganic Systems
Both solution and solid-state NMR has been use to look at a range of inorganic materials. Recently we have employed solid state 6,7Li MAS NMR and wide line 139La NMR to probe the impact of processing on Li-La-Nb/Ta Garnet electrolytes and lanthanum halides. High speed 1H MAS NMR has also been employed to look at the role of templating in ruthenium oxide electrodes. The dynamics in Uranyl Nanocapsules utilizing23Na solution and solid state has also been descriped in JACS:
Todd M. Alam, Zuolei Liao, May Nyman and Jonathan Yates, “Insight into Hydrogen Bonding of Uranyl Hydroxide Layers and Capsules by Use of 1H Magic-Angle Spinning NMR Spectroscopy”, J. Phys. Chem. C, 120(19), 10675-10685 (2016) DOI: 10.1021/acs.jpcc.6b02692