Nanocomposites Based on Dendrimers and Layered Molybdenum Disulfide
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Nanocomposites Based on Dendrimers and Layered Molybdenum Disulfide Rabin Bissessur1 · Maysun Benaaisha1 · Douglas C. Dahn2 · Alaa S. Abd‑El‑Aziz1 Received: 2 April 2020 / Accepted: 6 May 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Nanocomposites consisting of molybdenum disulfide (MoS2) and an organometallic dendrimer were synthesized by taking advantage of the exfoliating/restacking properties of lithiated molybdenum disulfide (LiMoS2). Based on the molecular weight of the dendrimer, nine different mole ratios of M oS2 to dendrimer were utilized in order to investigate the upper and lower limit of the dendrimer loading into the restacked MoS2. The developed nanocomposites were characterized by powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and variable-temperature electrical conductivity measurements. Our studies revealed that the ideal condition for preparing reproducible monophasic systems is at low dendrimer concentration, no greater than 1:0.125 mole ratio of M oS2 to dendrimer, and no lower than 1:0.002 mole ratio of MoS2 to dendrimer. Biphasic systems can be produced at mole ratio of MoS2 to dendrimer higher than 1:0.125. Additionally, the average crystallite size decreased as the mole ratio of the M oS2 to dendrimer was increased. Specifically, a change from 1:0.002 to 1:0.5 resulted in a noticeable decrease from 365 to 155 Å. The electrical conductivity of the nanocomposites drops as the amount of dendrimer increases. Variable-temperature conductivity data are consistent with a variable-range hopping model. Keywords Molybdenum disulfide · Organometallic dendrimer · Intercalation
1 Introduction Over the past decades, two-dimensional nanosheets materials such as transition metal dichalcogenides (TMDs) have been explored in-depth due to unique properties associated with their ultrathin structures [1]. Among TMD materials, molybdenum disulfide (MoS2) is one of the most attractive as it is naturally available and has a structure similar to graphite, which can be separated into monolayers [2]. MoS2 is organized in two layers of sulfur atoms covalently bound to a layer of Mo in the center, creating a nanosheet structure. The two-dimensional sheets of M oS2 are held together via weak van der Waals interaction [3]. The weak interaction between the MoS2 layers leads to a low friction coefficient and thus gives rise to its lubricating properties [4]. MoS2 * Rabin Bissessur [email protected] 1
Department of Chemistry, University of Prince Edward Island, Charlottetown, Canada
Department of Physics, University of Prince Edward Island, Charlottetown, Canada
2
has found applications as photocatalysts [5], transistors [6], sensors [7], and conductive filler in polymer composites [8]. The synthesis and characterization of organic–inorganic nanocomposite materials achieved via intercalation chemistry continues to be an important field of research. Many of the materials developed from organic–inorga
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