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Special Issue "NMR Characterization of Amorphous and Disordered Materials"

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Materials Science".

Deadline for manuscript submissions: 31 May 2020.

Special Issue Editor

Prof. Dr. Todd M. Alam
E-Mail Website
Guest Editor
Sandia National Laboratories, New Mexico, Department of Organic Material Sciences, NMR Spectroscopy Laboratory, Albuquerque, United States
Interests: NMR Spectroscopy characterization of materials; NMR Diffusometry; Polymer chemistry; aging and dynamics; Energy related materials; Ab initio chemical shift calculations

Special Issue Information

Dear Colleagues,

Nuclear magnetic resonance (NMR) spectroscopy continues to be a powerful technology for the characterization of materials at the molecular level. The application of new and advanced NMR techniques for probing amorphous or highly disordered materials continues to see major advances including the application of sophisticated heteronuclear, multiple dimensional, multiple quantum solid-state and solution NMR, dynamic nuclear polarization (DNP), fast magic angle spinning (MAS) NMR, and improved pulse field gradient (PFG) NMR diffusometry methods. The ability to probe nucleus-specific questions, combined with recent improvements in sensitivity, resolution, spin coherence manipulation, quantum chemical calculations, and multivariate/chemometric analysis, render NMR a rich field. These improvements are coupled with NMR’s ability to address an almost endless range of material properties including dynamics, binding events, surface interactions, phase transitions, morphology, reaction kinetics, hydrogen bond strengths, local and medium range structure, and ion/molecular diffusion and transport.

The focus of this Special Issue is to explore these recent NMR advances for the characterization of real-life materials being used in sensing, energy, quantum computing, advanced manufacturing, biomedical, and environmental remediation applications, including self-assembled materials, super-molecular and stimuli-responsive polymers, polymer membranes, composites, MOFS, liquid crystalline polymers, ceramics, glasses, biomaterials, catalyst, and surface-modified nanoparticles. This Issue will offer an overview of some of the exciting opportunities NMR can provide in material characterization.

Prof. Dr. Todd M. Alam
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. There is an Article Processing Charge (APC) for publication in this open access journal. For details about the APC please see here. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • solid-state NMR
  • MAS NMR
  • PFG NMR
  • materials
  • amorphous
  • structure
  • quantum chemical
  • morphology
  • structure

Published Papers (2 papers)

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Research

Open AccessArticle
The Monetite Structure Probed by Advanced Solid-State NMR Experimentation at Fast Magic-Angle Spinning
Int. J. Mol. Sci. 2019, 20(24), 6356; https://doi.org/10.3390/ijms20246356 - 17 Dec 2019
Cited by 2
Abstract
We present a solid-state nuclear magnetic resonance (NMR) spectroscopy study of the local 31P and 1H environments in monetite [CaHPO4; dicalcium phosphate anhydrous (DCPA)], as well as their relative spatial proximities. Each of the three 1H NMR peaks [...] Read more.
We present a solid-state nuclear magnetic resonance (NMR) spectroscopy study of the local 31 P and 1 H environments in monetite [CaHPO 4 ; dicalcium phosphate anhydrous (DCPA)], as well as their relative spatial proximities. Each of the three 1 H NMR peaks was unambiguously assigned to its respective crystallographically unique H site of monetite, while their pairwise spatial proximities were probed by homonuclear 1 H– 1 H double quantum–single quantum NMR experimentation under fast magic-angle spinning (MAS) of 66 kHz. We also examined the relative 1 H– 31 P proximities among the inequivalent {P1, P2} and {H1, H2, H3} sites in monetite; the corresponding shortest internuclear 1 H– 31 P distances accorded well with those of a previous neutron diffraction study. The NMR results from the monetite phase were also contrasted with those observed from the monetite component present in a pyrophosphate-bearing calcium phosphate cement, demonstrating that while the latter represents a disordered form of monetite, it shares all essential local features of the monetite structure. Full article
(This article belongs to the Special Issue NMR Characterization of Amorphous and Disordered Materials)
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Open AccessArticle
Static Solid Relaxation Ordered Spectroscopy: SS-ROSY
Int. J. Mol. Sci. 2019, 20(23), 5888; https://doi.org/10.3390/ijms20235888 - 24 Nov 2019
Abstract
A two-dimensional pulse sequence is introduced for correlating nuclear magnetic resonance anisotropic chemical shifts to a relaxation time (e.g., T1) in solids under static conditions. The sequence begins with a preparatory stage for measuring relaxation times, and is followed by a [...] Read more.
A two-dimensional pulse sequence is introduced for correlating nuclear magnetic resonance anisotropic chemical shifts to a relaxation time (e.g., T1) in solids under static conditions. The sequence begins with a preparatory stage for measuring relaxation times, and is followed by a multiple pulse sequence for homonuclear dipolar decoupling. Data analysis involves the use of Fourier transform, followed by a one-dimensional inverse Laplace transform for each frequency index. Experimental results acquired on solid samples demonstrate the general approach, and additional variations involving heteronuclear decoupling and magic angle spinning are discussed. Full article
(This article belongs to the Special Issue NMR Characterization of Amorphous and Disordered Materials)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Heterogeneity of Polymer Chain Dynamics at the Glass Transition:  Impact on the Solid State 1H NMR Spectral Line Shape

Authors: Todd M. Alam, Joshua Allers, and Brad H. Jones

Abstract: NMR spectroscopy continues to provide important molecular level details of dynamics in different polymer materials ranging from rubbers to highly crosslinked composites. It has recently been proposed that thermoset polymers with large dynamic heterogeneities can be fully cured at temperatures well below the final glass transition temperature (Tg). In this contribution we detail the use of solid state 1H NMR spectroscopy to measure the time scale of chain dynamics occurring as a function of temperature. The increased polymer chain fluctuations near Tg average the local homonuclear 1H-1H dipolar couplings to produce narrow NMR resonances. This occurs when the inverse of the motional correlation time becomes larger than the static 1H NMR line width. The impact of distributions (i.e. heterogeneity) in the polymer chain motional activation energy (and corresponding correlation times) on the NMR spectra near Tg are simulated and were used to extract the dynamic distributions for a series of thermosetting polymers with systematically varied heterogeneity.

Title:Comparing component analysis techniques for NMR spectra

Authors: Ryan McCarty, Nimish Ronghe, Mandy Woo, and Todd M. Alam

Abstract: Component analysis is used in spectroscopy to determine unique spectral features from a dataset of multiple spectra that individually contain mixtures of chemical compounds. Nuclear Magnetic Resonance (NMR) spectroscopy frequently results in spectra that contain both intentional components, such as several chemical species, as well as unintentional components, such as sample impurities, solvents, or background signal from MAS rotors; component analysis can separate individual signals and signal from noise. Using theoretical NMR signals, we generated datasets to benchmark the performance of several component analysis techniques (PCA, SparsePCA, IncrementalPCA, RPCA, PARAFAC, FastICA, JADE, MILCA, RADICAL, SIMPLISMA, several MCR variants, and SVD). We report on performance with 1 to 20 unknown components under clearly resolved and noisy conditions. We then apply these techniques to multi-spectra NMR datasets containing mixtures of chemical compounds. This motivates a discussion on practical approaches for applying these techniques to datasets of disordered materials and/or complex mixtures where peaks overlap and the concentration and peak shapes of individual components or chemical species are not previously known.

Title: Nuclear Magnetic Resonance Studies of Glass and Ceramic Electrolytes for Solid State Batteries – A Review

Authors: Daniel Morales; Steven Greenbaum

Abstract: The widespread demand energy storage for commercial products and services have led to great advancements in the field of Lithium-based battery research. Li-based Batteries utilizing solid state electrolytes have received much attention recently, as they safely allow for the use of Lithium-metal Anodes, which can significantly increase the total energy density. Of the solid electrolytes, Inorganic glass-ceramics and Li-containing Garnet-type solid electrolytes have shown much promise in the past few years, due to their high ionic conductivities compared to polymer-based electrolytes. This review covers recent work on novel glassy and garnet electrolyte materials, with a focus on the use of Solid-State Nuclear Magnetic Resonance Spectroscopy for studying structural dynamics and ion transport.

Title: Relaxation Ordered Spectroscopy of Static Solids: SS-ROSY

Authors: Gregory S. Boutis (The City University of New York), Ravinath Kausik ( Schlumberger-Doll Research)

Abstract: A two-dimensional pulse sequence is introduced for correlating nuclear magnetic resonance anisotropic chemical shift to a relaxation time (e.g. T$_{1}$) in solids under static conditions. The sequence begins with a preparatory stage for measuring relaxation times, and is followed by a multiple pulse sequence for homonuclear dipolar decoupling. Data analysis involves the use of Fourier transform, followed by a one-dimensional inverse Laplace transform for each frequency index. Experimental results acquired on solid samples demonstrate the general approach, and additional variations involving heteronuclear decoupling and magic angle spinning are discussed.

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