極性/非極性共溶劑退火法調控雙團鏈共聚物薄膜奈米微結構; Controls over Microdomain in Diblock Copolymer Thin Films by Polar/Nonpolar Cosolvent Annealing

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題名:	極性/非極性共溶劑退火法調控雙團鏈共聚物薄膜奈米微結構;Controls over Microdomain in Diblock Copolymer Thin Films by Polar/Nonpolar Cosolvent Annealing
作者:	徐士平;Shih-Ping Hsu
貢獻者:	化學工程與材料工程研究所
關鍵詞:	相轉變;溶解參數;浸鍍成膜;dip coating;solubility parameter;phase transition
日期:	2010-07-27
上傳時間:	2010-12-08 13:37:03 (UTC+8)
出版者:	國立中央大學
摘要:	本研究之重點在於製備大範圍有序垂直排向之六角圓柱陣列，所以從選擇溶解雙團鏈共聚物聚苯乙烯聚氧乙烯(PS-b-PEO)的溶劑、塗佈成膜、並以極性/非極性混合溶劑蒸氣在不同混合比例下退火處理，希望從這三道程序當中分別找出最適當的條件。首先以四種不同揮發速率的溶劑溶解PS-b-PEO，再以滴鍍(drop casting)的方式成膜，結果顯示溶劑揮發速率快慢會影響圓柱結構排列的有序性，其中以揮發速率最慢的甲苯在高分子濃度為2wt%時形成的垂直圓柱陣列最好，但缺點是薄膜表面相當不平整以及達到有序陣列的時間較長。改以旋鍍改善薄膜平整度，但其高轉速反而加速溶劑揮發的速率，使的垂直圓柱陣列相當無序。因此我們利用浸鍍可大幅改善這些問題，並進一步以不同的拖曳速率調控圓柱結構的排向，在低速拖曳時溶劑揮發主導圓柱排向為垂直式，而在高速拖曳時慣性力主導圓柱排向為水平式。最後，綜合上述結果我們選用甲苯當作溶劑配製2wt%的高分子溶劑以1mm/s的拖曳速率浸鍍成膜後，利用非極性溶劑甲苯混合極性溶劑(水或醇類溶劑)以不同的混合比例共溶劑蒸氣下溶劑退火處理，我們成功地在甲苯/乙醇混合比例為95：5製備出大範圍有序垂直的六角圓柱陣列，並在甲苯/乙醇混合比例為60：40發現圓柱結構會轉變成Fddd，以及甲苯/正丙醇混合比例為85：15發現圓柱結構和雙連續相(Double Gyroid)共存，証實PS-b-PEO以適當的比例混合選擇性溶劑(selective solvent)退火能夠誘導相轉變的發生。 I have systematically studied the morphology and orientation of microstructures in thin films of an asymmetric poly(styrene)-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymer after the thin films were subjected to solvent annealing in various vapors of nonpolar/polar cosolvents. In the first part of the thesis, I dissolved PS-b-PEO into the four solvents: toluene, benzene, tetrahydrofuran and chloroform. Each of the four solvents has a different evaporation rate. Therefore, I investigated the effect of the evaporation rate on the microphase-separated microdomains and their spatial ordering. Toluene has the slowest solvent rate. As a result, the evaporation of toluene led to hexagonal arrays of cylinders with a perpendicular orientation. On the other hand, I prepared thin films by drop casting and spin coating. It was found that drop casting couldn’t yield uniform thin films due to the coffee ring effect and that spin coating couldn’t generate microstructures with long-range ordering. Therefore, I used another coating approach, dip-coating, to prepare thin films instead. The low withdrawing rate (0.5 mm/s) induced to cylinders with a perpendicular orientation, and the high withdrawing rate (1.25 mm/s) induced to cylinders with a parallel orientation. In the second part of the thesis, I studied the morphologies in thin films after those films were subjected to solvent annealing in various solvent vapors (in mixed vapors of nonpolar/polar cosolvents). The various polar solvents in the mixed vapors were water, methanol, ethanol, 1-propanol, 1-butanol and 1-hexanol whereas the nonpolar solvent was toluene. PS-b-PEO thin films were first deposited on SiOx/Si by dip-coating at 1 mm/s from a 2 wt% toluene solution. I successfully fabricated the long range hexagonal arrays of perpendicularly-oriented cylinders upon solvent annealing thin films in the toluene/ethanol vapor of the volumetric fraction of 95/5. In addition, controling the mixed ratio of nonpolar/polar cosolvents led to complicated microphase-separated morphologies, such as the Fddd structure in the thin film with exposure to the toluene/ethanol vapor of 60/40 and the coexistence of double-gyroids and cylinders in the thin film with solvent annealing in the toluene /1-propanol vapor of the fraction of 85/15.
顯示於類別:	[化學工程與材料工程研究所] 博碩士論文

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