2004-08-012024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/677551摘要：塊狀共聚合物溶液，因著溶劑的選擇性以及溶劑的濃度，對其自身聚集的變化非常多元，可形成奈米級尺寸的各種微結構。目前雖然大部分的實驗結果均能定性地與理論計算結果一致，然而影響微結構形成的重要因素『溶劑選擇性』，隨著實際系統中共聚合物與溶劑之間交互作用力的不同，有著非常大的差異；因此，為了要透徹地了解所欲研究的實際塊狀共聚合物溶液系統如何應用於奈米級微結構中，首要的工作應為『溶劑選擇性』的定量分析，我們計畫比較理論計算與實驗方法所得到的結果，來定量分析出各項溶劑對於塊狀共聚合物的選擇性。所研究的系統為目前非常熱門的生物醫學材料，例如聚乙二醇─聚已內酯共聚物，其中聚已內酯在熔點以下會結晶，具有生物可分解性的優點；而聚乙二醇則是被認為對人體沒有毒性的高分子，因而在生物醫學研究上，佔有非常重要的地位。我們首先探討較稀薄的溶液，由於隨著溶劑濃度的改變，高分子可由單一鏈轉變為多條分子鏈聚集成微胞，因此運用溶液中流變性質、動態光散射、以及小角中子散射的分析，可得到所形成微胞的結構尺寸與形狀資訊，藉由與理論計算結果的比較，可望能將各塊狀分子與溶劑之間的交互作用參數決定出來。接下來，運用這些參數即可以利用自<br> Abstract: Block copolymer solutions can self-assemble into various microstructures due to the effects of solvent selectivity. Though most of the related experimental and theoretical results are qualitatively consistent, there exists little quantitative comparison between both fields. This is due to the fact that it is difficult to determine the solvent selectivity in real systems. Therefore, at first step, we propose to quantitatively determine the interaction parameters between each block and the solvent by comparing both experimental and numerical results. We consider a poly(ethylene-glycol) -polycaprolactone (PEG-PCL) diblock copolymer. In particular, PCL component can crystallize below the melting temperature. As PCL is biodegradable and PEG is non-toxic to human bodies, these materials play a very important role on the biomedical research. We first focus on the dilute copolymers in the presence of selective solvents. By varying solvent selectivity as well as the solvent concentration, these copolymer chains can aggregate into micelles. With the aid of rheology measurements, dynamic light scattering, and small-angle neutron scattering, the structural parameters, such as micelle shape and size, are analyzed and compared with the numerical results. As such, we can determine the interaction parameters between PEG-solvent and PCL-solvent. Once the solvent selectivity is obtained, we determine the corresponding phase diagrams of PEG-PCL block copolymer solutions by self-consistent mean-field theory. We examine the scaling of microdomain spacing in concentrated block copolymer solutions. In addition, we employ wide-angle X-ray diffraction, small-angle X-ray scattering, small-angle neutron Scattering, polarized optical microscopy, and differential scanning calorimeter (DSC) experiments to examine the phase behavior of PEG-PCL block copolymers in the presence of selective solvents. With this project, we wish to promote the research of biotechnology and nano-structured materials in Taiwan.塊狀共聚合物溶液自身聚集行為溶劑選擇性微結構尺寸標度性自洽平均場理論block copolymer solutionsself-assembly behaviorsolvent selectivityscaling of microdomain spacingself-consistent mean-field theory