Toward high-performance lubricants: Rational design and construction of supramolecular oil gels by amphiphilic telechelic polymers to stabilize two-dimensional nanomaterials in base oils

Colloidally Stable Graphite Oleogels by Pyrene-Functionalized Telechelic Polymers for Friction and Wear Reduction

“…In the WAXS regime, broad signals appeared at 18.8°(4.7 Å), corresponding to the local ordering of stearyl chains in the oleogels (Figure 3c). 27,28 Similar WAXS signals were also observed in Graphite@P m S 2n P m composite oleogels (Figure 3d). Meanwhile, WAXS signals at 2θ = 26.2°in Graphite@ P m S 2n P m were related to the (002) reflection of the exfoliated graphite.…”

“…21−24 Some of the dispersions are found to in situ form hydrogels, 18,25 organogels, 25 or ionic liquid gels. 26 These, together with our recent work on dynamic supramolecular oleogels constructed by telechelic polymers and 2D nanoparticles showcasing superior lubricating properties, 27,28 have prompted us to demonstrate here the first example of directly using pristine graphite as a lubricating oil additive. Such an idea is based on the rational construction of colloidally stable oleogels by pristine graphite and pyrene functionalized telechelic polymers through π−π interactions under mild conditions (Figure 1).…”

“…Graphite can be exfoliated into high quality graphene in the solutions of pyrene derivatives and pyrene-functionalized polymers by noncovalent π–π interactions between the pyrene group and the graphene. − Meanwhile, these pyrene-containing intercalants serve as stabilizing agents, preventing the restacking aggregation of the exfoliated graphene nanosheets in solution. − Some of the dispersions are found to in situ form hydrogels, , organogels, or ionic liquid gels . These, together with our recent work on dynamic supramolecular oleogels constructed by telechelic polymers and 2D nanoparticles showcasing superior lubricating properties, , have prompted us to demonstrate here the first example of directly using pristine graphite as a lubricating oil additive. Such an idea is based on the rational construction of colloidally stable oleogels by pristine graphite and pyrene functionalized telechelic polymers through π–π interactions under mild conditions (Figure ).…”

“…According to the mass fractal theory of small-angle scattering, it can be inferred that the Graphite@P m S 2 n P m oleogels self-assembled into a branched network structure. In the WAXS regime, broad signals appeared at 18.8° (4.7 Å), corresponding to the local ordering of stearyl chains in the oleogels (Figure c). , Similar WAXS signals were also observed in Graphite@P m S 2 n P m composite oleogels (Figure d). Meanwhile, WAXS signals at 2θ = 26.2° in Graphite@P m S 2 n P m were related to the (002) reflection of the exfoliated graphite.…”

“…All the worn steel surfaces exhibited the characteristic XPS signals of Fe 2p (710.7 and 724.4 eV) and O 1s (529.6 eV), indicative of the formation of Fe-oxide compounds such as FeO, Fe 2 O 3 , Fe 3 O 4 , and/or FeOOH (Figures S24–S26). , Other O 1s signals at 531.4 and 532.7 eV were attributed to the CO and CO bonds in P m S 2 n P m , respectively. , The C 1s signal of graphene was entirely superposed with those of CC/CH and CO bonds. ,, Additionally, a clear C 1s peak was fitted at 283.60 eV, which probably originated from Fe 3 C in the inherent cementite of the steel discs . Moreover, SEM elemental mapping studies of the wear scars by energy-dispersive X-ray spectroscopy (EDS) showed that Fe, C, and O were homogeneously distributed on the worn steel surfaces (Figures S27–S29).…”