Recent studies have been directed toward using

graphite nanoplatelets (GNPs) and graphene as a substrate to support nanostructures (e.g., quantum dots, metal catalysts, magnetic nanoparticles, etc.) because of their wide surface area, chemical stability, mechanical GDC-973 strength, and flexibility [2–4]. sp 2 carbon nanoforms (e.g., fullerenes, CNTs, graphite nanoplatelets, and graphene) can be chemically cross-linked and Idasanutlin purchase polymerized by reaction with elemental sulfur. The resulting synthetic solid phases can be considered as a sort of three-dimensional polymers of sulfur and structurally complex carbon-based monomers. This carbon-sulfur chemical reaction may result in a certain importance in the preparation of novel bulky nanostructured materials [5]. For example, a highly spongy graphite-based material (graphite aerogels) can be prepared by drying concentrated GNP colloids, achieved by exfoliation of expanded graphite in nonpolar liquids with ultrasounds [6]. This

novel material is quite fragile and has a measured apparent density of 0.5 g/cm3. A mechanical stabilization treatment is required to exploit this system in technological applications. The carbon-sulfur chemical reaction can be advantageously used for the mechanical stabilization of the very fragile spongy graphite material. The introduction of sulfur in this spongy graphite structure is quite simple since the sulfur molecules (S8)

are soluble in nonpolar organic selleck chemicals llc media (hydrocarbons, etc.), and it can be dissolved in the GNP colloid before the drying process. Then, the dry GNP-based material is heated at ca. 180°C to allow the sulfur molecules to open, producing sulfur bi-radicals (∙S8 ∙) which bridge the graphene layers of closed nanoplatelets [7]. In particular, the ring of sulfur molecule (S8) breaks at a temperature of ca. 169°C, producing linear sulfur bi-radical fragments, and such endothermal process RVX-208 is named as λ-transition [8]. The permanence of the system at temperatures above the λ-transition allows the polysulfur molecular chains (C-(S) n -C) to break successively and the generated sulfur radicals to react again with the edges of graphene sheets above to achieve a high density of monosulfur chemical cross-links (C-S-C) between them. The monosulfur bridges allow electron delocalization among the graphene sheets, and therefore, they represent a sort of electrical connections in the material. When the spongy graphite is devoted to technological applications in the electrical/electronic field (e.g., supercapacitor electrodes, battery cathodes, electrodes for electrolytic cells, etc.) [9], the presence of monosulfur bridges among the GNP unities is a very convenient characteristic. In addition, the material stiffness is related to the length of sulfur bridges, and monosulfur connections lead to a much more rigid and tough material.

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