Fabrication of graphene-based surface coatings through self-assembly may provide an affordable alternative to chemical vacuum deposition. Herein, we exploited the self-assembly of graphene oxide at the oil/water interfaces to form monolayers of 2D carbons on solid surfaces with different surface energy. We showed that interfacial monolayers with controlled packing density of graphene oxide can be deposited on the hydrophilic surfaces such as silicon wafers and quartz glass as well as on the hydrophobic surface of Teflon. Graphene oxide attained flat arrangements in the monolayers on hydrophilic surfaces and yielded the films of partially scrolled particles on the surface of Teflon. The as-formed graphene oxide surface coatings underwent rapid reduction under microwave irradiation at 1000W. The efficiency of reduction was dependent on the ability of the supporting material to absorb microwaves: silicon wafer > quartz glass > Teflon. The single layers of graphene oxide reduced on the surface of silicon wafers showed extraordinary low sheet resistance 1.2 kOhm.sq-1, whereas those on Teflon exhibited low electrical properties (3.0 105 kOhm.sq-1). The results suggest that this facile and scalable soft-matter method for producing surface films of graphene oxide can be extended to other practically relevant combinations of graphene-based colloids and supporting materials.
The graphite melting temperature remains poorly determined despite the considerable effort accomplished since the work of Bundy (1963). The absence of a consensus on its melting temperature at normal conditions has been considered as a technical problem that motivated more and more sophisticated experiments. The experimental evidences of the maximum on the graphite melting curve resulted in the liquid–liquid phase transition hypothesis for liquid carbon. However this hypothesis still requires a sound evidence. In this work using atomistic methods we focus on the kinetics of graphite melting and show that the experimental puzzles can be resolved by considering the graphite melting as a process in the non-equilibrium superheated solid. The unusually slow melting kinetics results in the existence of the superheated graphite at the microsecond timescale and thus biases the measurements of its equilibrium melting temperature.