Clay particles - potential of positron annihilation lifetime spectroscopy (PALS) for studying interlayer spacing

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Date
2010-08-01
Journal Title
Journal ISSN
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Publisher
Institute of Physics
Abstract
Characterisation of clays is generally achieved by traditional methods, such as X-ray diffraction (XRD) and transmission electron microscopy (TEM). However, clays are often difficult to characterise due to lack of long-range order, thus these tools are not always reliable. Because interlayer spacing in clays can be adjusted to house molecules, there is growing interest to use these materials for drug delivery. Positron annihilation lifetime spectroscopy (PALS) was examined as an alternative tool to characterise a series of well-known clays. XRD of two layered double hydroxides; MgAl-LDH and MgGd-LDH, natural hectorite, fluoromica and laponite, and their PALS spectra were compared. XRD data was used to calculate the interlayer d- spacing in these materials and results show a decrease in interlayer spacing as the heavy metal ions are substituted for those of large ionic radii. Similar results were obtained for PALS data. This preliminary study suggests PALS has potential as a routine tool for characterising clay particles. Further work will examine the sensitivity and reliability of PALS to percent of metal doping and hydration in clay microstructure. © 2020 IOP Publishing
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Keywords
Clays, X-ray diffraction, Transmission electron microscopy, Annihilation, Positrons, Heavy metals
Citation
Fong, N., Guagliardo, P., Williams, J., Musumeci, A., Martin, D., & Smith, S. V. (2010). Clay particles - potential of positron annihilation lifetime spectroscopy (PALS) for studying interlayer spacing. Paper presented to the 12th International Workshop on Slow Positron Beam Techniques for Solids, Surfaces, Atoms and Molecules (SLOPOS12), 1st - 6th August 2010. All Seasons Resort: Magnetic Island, North Queensland, Australia. In Journal of Physics: Conference Series, 262(1), 012022. doi:10.1088/1742-6596/262/1/012022