| Summary: | 碩士 === 中原大學 === 應用物理研究所 === 94 === In this thesis, we introduce the principle and application of the Langmuir-Blodgett technique. By this method, we fabricate the ordered Polystyrene 2D structure, and discuss the relation between the surface pressure and the area of the LB-film in the process of forming the 2D structure.
The surface pressure increases as compressing the bipolar molecules on the air/water interface continuously. As the separation distance between molecules decreasing, the surface pressure goes through two phase transitions (2D-gas to 2D-liquid and 2D-liquid to 2D-solid). If PS micro-balls have the similar behavior on the air/water interface, such two phase transitions should be observed.
In the case of 1�慆 in diameter, we observe two phase transitions successfully. In the 150nm and 250nm cases, we only discover one phase transition (2D-gas to2D-liquid). As the phase transition occurs, the ratio of separation distance to micro-ball diameter (D/R value) is less than unity. This phenomenon is possibly due to the non-uniformity caused by the thermal fluctuation.
More over, we try to disperse silver nano-powder into HPLC grade chloroform to get the suspension with ultrasonic cleaner. However, the concentration of the suspension is far thinner than 1mg/ml, so it is difficult to apply in this LB technique.
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