以Langmuir-Blodgett法製備二維奈米結構之研究

本論文將介紹Langmuuir-Blodgett technique (LB法)的基本原理及其應用。我們將利用此方法製作聚苯乙烯(Polystyrene, PS)微球之二維有序結構，並討論在形成二維有序結構的過程中，表面壓力(Surface Pressure)與薄膜面積的關係。兩性分子材料在機械手臂的持續擠壓之下，水面上的兩性分子薄膜之表面壓力將隨之上升。隨著分子間距的減少，此分子薄膜的表面壓力將經歷由二維氣體轉變為二維液體，進而成為二維固體的兩次相轉變。假設PS微球也有相同的行為，在水面上的PS微球薄膜也將經歷如此的兩次相轉變。在粒徑1慆的樣品，我們成功地觀察到兩次的相轉變。在250nm及150nm的樣品中，我們只有觀察到一次的相變化，經過計算其D/R(微球間距/粒徑比)值，我們發現在相變化發生時，D/R值即小於1，其原因可能是150nm及250nm的PS微球較易受熱能擾動而形成三維的結構。我們另外嘗試以奈米銀粒子為材料，利用超音波震盪法將粉末均勻分散懸浮於HPLC級氯仿中，我們發現此方法所得到的懸浮液(suspension)，其濃度遠低於1mg / ml，如此將難以應用在LB法製程上。

關鍵字

聚苯乙烯； LB膜；奈米結構；薄膜

並列摘要

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.

並列關鍵字

nanostructure ； LB films ； polystyrene ； PS ； Langmuir-Blodgett films

參考文獻

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[1] 陳唯欣 “鈀(II)-咪唑錯合物分子Langmuir-Blodgett 薄膜之製備與鑑定” 國立東華大學化學系 93碩士論文