dc.description.abstract | In this thesis, the mechanism of fabricated graphene by electrolytic exfoliation is investigated. The experiment is divided into three parts. In the first part, we discuss the surface properties of graphite electrode through physical roughness, wetting phenomena, surface conductivity, and chemical composition. The anodic graphite surface react with oxygen then form a graphite oxide layer during electrolytic exfoliation. Therefore, we infer that the particles which are exfoliated from the surface of anode are graphite oxide. Furthermore, we can control the contact angle of graphite surface by electrolysis.
In the second part, we analyze the surface properties of exfoliated graphite oxide particles through particle size, zeta potential, UV-Vis spectrophotometer, and Thermogravimetric analysis. In these results, we observed that the oxidation order of graphite oxide nanoparticles by Electrolytic exfoliation is lower than that by Hummer method. Furthermore, we can control oxidation order of graphite oxide nanoparticles by tuning the pH of electrolyte.
In the third part, we discuss the wetting behavior of graphite surface. A superhydrophobic graphite surface has been fabricated through two facile physical steps, peeling and ultrasonicating. Peeling yields micron-scale roughening, and thus a highly hydrophobic surface is obtained. Further ultrasonicating results in a superhydrophobic surface with nanostructure embedded in microstructure. The nanostructure leads to networklike pores on the superhydrophobic film and convective Ostwald ripening is observed. Owing to their distinct resistance to liquid imbibition, contact angle hysteresis on hydrophobic and superhydrophobic surfaces is fundamentally different. Moreover, the adhesive force on a superhydrophobic surface grows with the contact time, and such aging effect is absent on hydrophobic graphite surface.
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