| Summary: | 博士 === 國立臺北科技大學 === 電機工程系 === 107 === This dissertation uses the arc formed by the point discharge of an Electric Discharge Machine (EDM) to prepare graphene colloid using the Electrical Spark Discharge Method (ESDM). This preparation method successfully proposes a novel nanometer process technology for graphite material, where the graphite material is molten at high temperature by arc discharge machining in Deionized water (DI water), the material is exfoliated, and cooled to form graphene. The prepared graphite nano-structure can uniformly disperse in DI water, remain suspended without any surfactants or dispersants, and be stored at normal room temperature. It can be rapidly prepared at normal temperature and pressure, and the process is free of chemical pollutants, thus, this is an environmentally friendly preparation method. The graphene is prepared under five different groups of discharge parameters using graphite rod electrodes. The Tyndall effect is observed first to confirm there is nano-sized graphene in the solution. The optical performance of graphene is analyzed by UV–Vis spectrophotometer. The Raman spectrometer measured performance spectrum lines are called G-band, D-band, and 2D-band. The zeta potential of graphene is analyzed by Zetasizer. The transmission electron microscope (TEM) can clearly display the shape, size, and dispersion. The findings show that graphene synthesized by this method is only as thick as one single atom. When the aforesaid instruments confirm the correctness of the parameter settings for this experiment, the negatively charged graphene colloid can be measured, the zeta potential is -43.8 mV, the particles are unlikely to settle down, and suspension stability is good. Finally, it is diluted at different times with 1000 ppm graphene oxide (GO) dispersion, compared with the results of this experiment, and the graphene colloid concentration values at different preparation times can be obtained, in order to know the differences between graphenes prepared by the chemical method and physical method. The results of this experiment show that using arc discharge in DI water to prepare graphene colloid is an inexpensive, quick, effective, and novel method.
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