雙嵌段共聚物（block copolymers）在高分子科學中因其自組裝特性和多樣的微相結構而備受關注。這些特性使得它們在奈米結構材料領域有著廣泛的應用前景。本研究聚焦於雙嵌段共聚物聚(苯乙烯-b-甲基丙烯酸甲酯）(PS21k-b-PMMA21k)與均聚物聚苯乙烯(PS6k)的混摻系統，特別是在混摻比例75/25時，其微相結構顯示出最為豐富的多樣性。了解並控制這些微相結構對於製備具有功能性的奈米材料至關重要。
本研究旨在通過調整均聚物Polystyrene(PS)的分散性（Polydispersity Index, PDI），觀察混摻薄膜內部微相結構的變化及由自由表面至基材的平面結構表徵。希望通過改變PDI來實現對微相結構的精確控制，並探討介穩態結構的穩定性，以期為高性能材料的設計提供理論依據。
選取PDI=1.05、1.33、1.50三種具有不同PDI的PS均聚物，數量平均分子量介於6.0~6.1k，與雙嵌段共聚物PS21k-b-PMMA21k按照75/25的比例混摻，製備成薄膜。利用低掠角小角度X光散射儀（GISAXS）、原子力顯微鏡（AFM）及掃描式電子顯微鏡（SEM）等技術對薄膜內部的微相結構進行表徵分析。再進一步分析結構定量化，利用公式擬合尋找變化趨勢。
結果顯示，無論均聚物PDI的高低，表面均觀察到穿孔層結構。內部結構隨PDI的增加呈現出不同的變化趨勢：從低PDI的水平圓柱結構，到中等PDI時的水平圓柱和穿孔層共存，再到高PDI時的穿孔層結構。此外，隨著PDI的增加，結構的有序性逐漸降低。研究發現，加入適度PDI的均聚物可以提高介穩態結構的穩定性，但過大PDI的均聚物則會破壞結構的有序性。
發現均聚物PDI的選擇對於薄膜結構的轉變及有序性的調控至關重要。本論文提供了通過改變均聚物PDI來控制微相結構和介穩態結構穩定性的概念，對於製備具有功能性的奈米材料有指導意義。

This study investigates the blend system of the diblock copolymer poly(styrene-b-methyl methacrylate) (PS21k-b-PMMA21k) and the homopolymer polystyrene (PS6k) at a 75/25 ratio, focusing on the influence of the polydispersity index (PDI) of the homopolymer on microphase structures. The goal is to control these microphase structures and explore the stability of metastable states by adjusting the PDI.
Methods used include grazing-incidence small-angle X-ray scattering (GISAXS), atomic force microscopy (AFM), and scanning electron microscopy (SEM) to characterize the internal structures of films prepared with homopolymers of different PDI (1.05, 1.33, 1.50).
Results indicate that all films show perforated layer structures on the surface regardless of PDI. Internal structures transition from horizontal cylinders at low PDI, to a coexistence of horizontal cylinders and perforated layers at medium PDI, to perforated layers at high PDI. Structural order decreases with increasing PDI.
The study concludes that selecting the appropriate PDI is important for the transformation of the film structure and the adjustment of the ordering. The findings provide insights into controlling microphase structures and the stability of metastable states, offering guidance for the design of functional nanomaterials.

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