Direct Exfoliation of Graphite into Graphene by Pyrene-Based Molecules as Molecular-Level Wedges: A Tribological View

Initial Studies Directed toward the Rational Design of Aqueous Graphene Dispersants

“…These values are in remarkably close agreement with those previously calculated, with the total IE being remarkably close to our QM value (vide supra). As anticipated, interaction of PSA with graphene generates a number of rapidly interconverting topologies in which the pyrene core of the dispersant is able to glide along the surface of the graphene (Supporting Information, Figure S12 snapshots c–e). It should be noted that in the final averaged structure for PSA adsorbed onto the graphene surface, both O(18) and O(20) are directed toward the surface of the graphene, whereas O(19) is directed toward the bulk solvent.…”

“…In passing, it should be noted that the conformation adopted by the butyl side chain in PBSA in Figure 6 (snapshot c) is also similar to that proposed for the most stable conformation adopted by PBA when adsorbed onto the surface of graphene. 34,72…”

“…For example, it is possible that the dispersant used in the present study (PBSA), which may well aggregate in aqueous solution, 59,75 could generate bi- or multilayers 77 on the graphene surface or that PBSA could act as a molecular wedge during exfoliation. 72 A search of the literature reveals that many authors are circumspect concerning the nature of dispersant graphene aggregates, as has been recently noted by Bühlmann and co-workers, 78 who conclude that monolayer formation of the dispersant on the graphene surface is often assumed and not pursued rigorously. Of relevance to our investigation is that there is evidence for the formation of monolayers when pyrenebutyric acid, which is structurally similar to PBSA, is deposited onto the surface graphene.…”

“…In the parent compound, PSA, a similar QM analysis (Supporting Information) indicates that two of the oxygen atoms of the sulfonate moiety are pointing either toward the surface of the graphene or parallel to it, leaving the third oxygen exposed to the bulk solvent (Figure ). ,, …”

Molecularly templated reaction for forming poly(dimethyl siloxane)–graphene oxide composite elastomers

“…Recently, Cai et al have theoretically investigated the structure, geometry, and interaction between pyrene or pyrene derivatives with graphene surfaces . They confirmed that pyrenes bind to the graphene in a slightly off‐set manner, where half of the pyrene carbon atoms lie directly over the center of hexagons in the lower graphene sheet, and the other half of the pyrene carbon atoms lie directly over graphene carbon atoms.…”