Special Issue "Characterization of Amorphous Materials"

A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (15 February 2018).

Special Issue Editors

Assoc. Prof. Jacqueline Anne Johnson
E-Mail Website
Guest Editor
Mechanical, Aerospace and Biomedical Engineering, The University of Tn Space Institute Tullahoma, TN 37388-9700, USA
Dr. R. Lee Leonard
E-Mail Website
Guest Editor
Mechanical, Aerospace, Biomedical Engineering (MABE), University of Tennessee Space Institute, 411 B. H. Goethert Parkway, MS-35 Tullahoma, TN 37388-9700, USA

Special Issue Information

Dear Colleagues,

We have entered the “Glass Age” due to the revolution in electronic devices, such as smart phones, liquid crystal displays, wearable fitness devices, tablets, optical fiber communication, and automotive interior displays, to name a few. Glass is an amorphous material, and, as such, has no long-range order as crystals do. This characteristic presents special challenges in terms of elucidating their structure and properties. The term amorphous has been used synonymously with glass, but there are several other types of amorphous materials, such as polymers, gels, thin films, metals, and nanostructured materials. Glass is a material that undergoes a glass transition temperature, Tg, where the material is transformed from a hard, rigid solid state to a more flexible, rubbery state. This property can be measured by Differential Scanning Calorimetry (DSC) and gives information on the type of glass. For example, silica has a relatively high glass transition temperature, whereas fluorides have a comparatively low one. Amorphous polymers generally have a Tg much lower than that found in a traditional glass.

There are many techniques that can be used to determine the structure/properties of a glass or other amorphous materials, such as Total Neutron Scattering, Fluctuation Microscopy, Ellipsometry, Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Secondary Ion Mass Spectroscopy (SIMS) or Time-of-Flight SIMS, and Scanning Electron Microscopy (SEM) to name a few. The properties that we can measure are numerous with a variety in relevance that is dependent on the application. These may be nearest-neighbor interactions, mechanical properties, depth profiles, optical properties and environmental durability.

The versatility of glass makes their possibilities almost limitless. With this is mind, it is our pleasure to invite you to submit a manuscript for this Special Issue. Full papers, communications, and reviews are all welcome.

Prof. Jacqueline Johnson
Dr. Lee Leonard
Guest Editors

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. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). 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

  • Chracterization
  • Glass
  • Polymers
  • Amorphous
  • Structure
  • Nanomaterials

Published Papers (5 papers)

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Research

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Open AccessArticle
A Novel Synthesis Routine for Woodwardite and Its Affinity towards Light (La, Ce, Nd) and Heavy (Gd and Y) Rare Earth Elements
Materials 2018, 11(1), 130; https://doi.org/10.3390/ma11010130 - 14 Jan 2018
Cited by 2
Abstract
A synthetic Cu-Al-SO4 layered double hydroxide (LDH), analogue to the mineral woodwardite [Cu1−xAlx(SO4)x/2(OH)2·nH2O], with x < 0.5 and n ≤ 3x/2, was synthesised by adding a solution of Cu and [...] Read more.
A synthetic Cu-Al-SO4 layered double hydroxide (LDH), analogue to the mineral woodwardite [Cu1−xAlx(SO4)x/2(OH)2·nH2O], with x < 0.5 and n ≤ 3x/2, was synthesised by adding a solution of Cu and Al sulphates to a solution with NaOH. The pH values were kept constant at 8.0 and 10.0 by a continuous addition of NaOH. The material obtained had poor crystallinity, turbostratic structure, and consisted of nanoscopic crystallites. The analyses performed in order to characterise the obtained materials (X-ray diffraction (XRD), thermogravimetry (TG), and Fourier Transform Infra-Red (FTIR) spectroscopy) showed that the Cu-Al-SO4 LDH is very similar to woodwardite, although it has a smaller layer spacing, presumably due to a lesser water content than in natural samples. The synthesis was performed by adding light rare earth elements (LREEs) (La, Ce, and Nd) and heavy rare earth elements (HREEs) (Gd and Y) in order to test the affinity of the Cu-Al-SO4 LDH to the incorporation of REEs. The concentration of rare earth elements (REEs) in the solid fraction was in the range of 3.5–8 wt %. The results showed a good affinity for HREE and Nd, especially for materials synthesised at pH 10.0, whereas the affinities for Ce and La were much lower or non-existent. The thermal decomposition of the REE-doped materials generates a mixture of Cu, Al, and REE oxides, making them interesting as precursors in REE oxide synthesis. Full article
(This article belongs to the Special Issue Characterization of Amorphous Materials)
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Open AccessArticle
Acoustic Anomalies and Fast Relaxation Dynamics of Amorphous Progesterone as Revealed by Brillouin Light Scattering
Materials 2017, 10(12), 1426; https://doi.org/10.3390/ma10121426 - 14 Dec 2017
Cited by 1
Abstract
The amorphous state of pharmaceuticals has attracted much attention due to its high bioavailability and other advantages. The stability of the amorphous state in relation with the local molecular mobility is important from both fundamental and practical points of view. The acoustic properties [...] Read more.
The amorphous state of pharmaceuticals has attracted much attention due to its high bioavailability and other advantages. The stability of the amorphous state in relation with the local molecular mobility is important from both fundamental and practical points of view. The acoustic properties of amorphous progesterone, one of the representative steroid hormones, were investigated by using a Brillouin inelastic light scattering technique. The Brillouin spectrum of the longitudinal acoustic mode exhibited distinct changes at the glass transition and the cold-crystallization temperatures. The acoustic dispersions of the longitudinal sound velocity and the acoustic absorption coefficient were attributed to the fast and possibly the secondary relaxation processes in the glassy and supercooled liquid states, while the structural relaxation process was considered as the dominant origin for the significant acoustic damping observed even in the liquid phase. The persisting acoustic dispersion in the liquid state was attributed to the single-molecule nature of the progesterone which does not exhibit hydrogen bonds in the condensed states. Full article
(This article belongs to the Special Issue Characterization of Amorphous Materials)
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Open AccessFeature PaperArticle
The Structure of Liquid and Amorphous Hafnia
Materials 2017, 10(11), 1290; https://doi.org/10.3390/ma10111290 - 10 Nov 2017
Cited by 8
Abstract
Understanding the atomic structure of amorphous solids is important in predicting and tuning their macroscopic behavior. Here, we use a combination of high-energy X-ray diffraction, neutron diffraction, and molecular dynamics simulations to benchmark the atomic interactions in the high temperature stable liquid and [...] Read more.
Understanding the atomic structure of amorphous solids is important in predicting and tuning their macroscopic behavior. Here, we use a combination of high-energy X-ray diffraction, neutron diffraction, and molecular dynamics simulations to benchmark the atomic interactions in the high temperature stable liquid and low-density amorphous solid states of hafnia. The diffraction results reveal an average Hf–O coordination number of ~7 exists in both the liquid and amorphous nanoparticle forms studied. The measured pair distribution functions are compared to those generated from several simulation models in the literature. We have also performed ab initio and classical molecular dynamics simulations that show density has a strong effect on the polyhedral connectivity. The liquid shows a broad distribution of Hf–Hf interactions, while the formation of low-density amorphous nanoclusters can reproduce the sharp split peak in the Hf–Hf partial pair distribution function observed in experiment. The agglomeration of amorphous nanoparticles condensed from the gas phase is associated with the formation of both edge-sharing and corner-sharing HfO6,7 polyhedra resembling that observed in the monoclinic phase. Full article
(This article belongs to the Special Issue Characterization of Amorphous Materials)
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Review

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Open AccessFeature PaperReview
NMR Spectroscopy in Glass Science: A Review of the Elements
Materials 2018, 11(4), 476; https://doi.org/10.3390/ma11040476 - 22 Mar 2018
Cited by 7
Abstract
The study of inorganic glass structure is critically important for basic glass science and especially the commercial development of glasses for a variety of technological uses. One of the best means by which to achieve this understanding is through application of solid-state nuclear [...] Read more.
The study of inorganic glass structure is critically important for basic glass science and especially the commercial development of glasses for a variety of technological uses. One of the best means by which to achieve this understanding is through application of solid-state nuclear magnetic resonance (NMR) spectroscopy, which has a long and interesting history. This technique is element specific, but highly complex, and thus, one of the many inquiries made by non-NMR specialists working in glass science is what type of information and which elements can be studied by this method. This review presents a summary of the different elements that are amenable to the study of glasses by NMR spectroscopy and provides examples of the type of atomic level structural information that can be achieved. It serves to inform the non-specialist working in glass science and technology about some of the benefits and challenges involved in the study of inorganic glass structure using modern, readily-available NMR methods. Full article
(This article belongs to the Special Issue Characterization of Amorphous Materials)
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Open AccessReview
X-ray Absorption Fine Structure (XAFS) Studies of Oxide Glasses—A 45-Year Overview
Materials 2018, 11(2), 204; https://doi.org/10.3390/ma11020204 - 28 Jan 2018
Cited by 9
Abstract
X-ray Absorption Fine Structure (XAFS) spectroscopy has been widely used to characterize the short-range order of glassy materials since the theoretical basis was established 45 years ago. Soon after the technique became accessible, mainly due to the existence of Synchrotron laboratories, a wide [...] Read more.
X-ray Absorption Fine Structure (XAFS) spectroscopy has been widely used to characterize the short-range order of glassy materials since the theoretical basis was established 45 years ago. Soon after the technique became accessible, mainly due to the existence of Synchrotron laboratories, a wide range of glassy materials was characterized. Silicate glasses have been the most studied because they are easy to prepare, they have commercial value and are similar to natural glasses, but borate, germanate, phosphate, tellurite and other less frequent oxide glasses have also been studied. In this manuscript, we review reported advances in the structural characterization of oxide-based glasses using this technique. A focus is on structural characterization of transition metal ions, especially Ti, Fe, and Ni, and their role in different properties of synthetic oxide-based glasses, as well as their important function in the formation of natural glasses and magmas, and in nucleation and crystallization. We also give some examples of XAFS applications for structural characterization of glasses submitted to high pressure, glasses used to store radioactive waste and medieval glasses. This updated, comprehensive review will likely serve as a useful guide to clarify the details of the short-range structure of oxide glasses. Full article
(This article belongs to the Special Issue Characterization of Amorphous Materials)
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