| Summary: | 碩士 === 國立中興大學 === 化學工程學系所 === 100 === Nanotechnology is one of the most important science technologies in the 21st century. With the reduction of size；We discover that the various characteristics exhibited by nano-fluids show huge differences from those of micro-fluids. However, we have encountered problems to put nano-fluids into practice. For instance, many small particles of metal would aggregate because the particles are too small. A variety of metal perform better when they are at the nanometer scale, but we also face such problems as low stability and poor dispersion. This study uses many references and discusses how nano-fluids disperse in order to find out what affects dispersion. The results indicate that the nano-fluids of titanium dioxide are very stable, but the nano-fluids of other metal show no significant changes. Therefore, we add a second generation of nano particles based on carbon black to produce the titanium dioxide/carbon black nano-fluids. In this way, we hope to enhance the characteristics of nano-fluids and to maintain their stability and dispersion. We explore the differences between ultrasonic process and grinding process, to compare the dispersion of carbon black in order to find the best method to prepare and produce titanium dioxide/carbon black composite nano-fluids, and we find that it is uniform on ultrasonic process. When we put the composite nano-fluids under the scope of atomic force microscopy, we find that the boundaries of particle sizes are blurred. Then we use dynamic light scattering particle size analyzer nano and transmission electron microscopy to examine the dispersion of carbon black nano-fluids. We prepare 0.5w%, 2.0w% and 5.0w% of titanium dioxide, each added with 0.0025g of carbon black, to produce 64.9nm, 75.6nm and 91.3nm of titanium dioxide/carbon black composite nano-fluids. The fluids are respectively placed for 8, 4 and 2 hours and can still maintain the sizes below 100nm. Then we examine through transmission electron microscopy, which better supports the results we obtain by using dynamic light scattering particle size analyzer nano. We find that 0.5w%, 2.0w% and 5.0w% of TiO2 added with 0.0025 g of carbon black nano-fluids are approximately 30nm, 60nm, 80nm in sizes. After preparing the nano-fluids with good dispersion, we measure the characteristics of these nano-fluids and do rheological analysis on titanium dioxide/carbon black composite nano-fluids. These nano-fluids have as Newtonian fluids. Increasing the amount of carbon black does not greatly affect the viscosity of nano-fluids, which can be regarded as a feature of the original base fluid.
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