Fig. 7
From: Sulfur-Doped Alkylated Graphene Oxide as High-Performance Lubricant Additive
The optical photographs of the SA-GO (which is prepared by the reactions of octadecylamine and the sulfur-doped graphene oxide; the oxidation time of the graphene oxide is 24 h) ultrasonically dispersed in the PAO4 base oil (a) and the 928 aviation lubrication oil (b) and the PAO4 (c) and 928 (d) oil sample stand still for 24 h, respectively; the normalized adsorption of the SA-GO in PAO4 (e) and 928 (f) oil samples (a–d, examined by UV-vis spectrophotometer) with the concentration of SA-GO is 1, 2.5, and 5 × 10−4 wt% within 1440 min