芴系硬桿-柔軟嵌段式共聚物：PF-b-P4VP之合成、型態及特性研究

Abstract

共軛硬桿-柔軟嵌段共聚高分子在許多領域皆具有良好的應用潛力，包括電子元件、感測設備、光學材料及生物科技等而備受矚目。軟段高分子的導入不但能改善共軛嵌段高分子的光電特性，更能增加其應用性。本論文的主要目的在於由實驗合成出一系列不同比例之芴系硬桿-軟段嵌段共聚高分子以及利用形成不同等級制的自組裝超分子結構來控制聚芴硬鏈段的型態。並且討論在不同比例下芴系硬桿-柔軟嵌段共聚高分子的薄膜型態學與其光物理性質。 本文的第一個部分(第二章)，我們成功的合成出一系列不同硬桿-軟段比例的poly[2,7-(9,9-dihexylfluorene)]-block-poly(4-vinylpyridine)嵌段共聚物(PF-b-P4VP)。藉由調控軟硬鏈段比例及薄膜的厚度，PF-b-P4VP嵌段共聚物可形成不同的自組裝結構，包括層狀及不規整的結構。然而自組裝結構的變化會使芴系高分子產生不同的聚集形態，進而影響其螢光發射特性。 本研究的第二個部分(第三章)，藉由氫鍵作用力，我們可使3-Pentadecylphenol (PDP)與PF-b-P4VP嵌段共聚物形成不同等級制的自組裝超分子結構。經由FTIR實驗，證實了氫鍵作用力的存在。改變軟硬鏈段與PDP的比例，我們可以觀察到不同於前一章的自組裝結構，如不規整的圓柱、柱狀-球型複合體及球體等。對應於光電性質，提升P4VP(PDP)x混合相的含量，會阻礙聚芴鏈段聚集，可以導致螢光光譜產生變化。

π-conjugated rod-coil block copolymers have been widely investigated recently since they have great potential applications in many aspects, including electronic devices, sensors, optical materials, biotechnology and etc. Such block copolymers could not only manipulate the electron and optoelectronic properties but also provide the flexibility on morphology control. In this thesis, the main objective is to synthesize a series of different rod/coil ratios polyfluorene-based block copolymers and form the hierarchical self-organized structures in order to control the orientation of PF nanodomains. Furthermore, the thin film state morphologies of those polymers and photophysical properties were explored. In the first part of this thesis (chapter 2), an amphiphilic rod-coil block copolymer, poly[2,7-(9,9-dihexylfluorene)]-block-poly(4-vinylpyridine) (PF-b-P4VP) with diverse rod/coil ratios was synthesized and characterized. Various self-assemble morphologies, including lamellar and irregular structure, were observed using AFM, as the PF and P4VP blocks compositions are similar to each other. The morphological transformation led to a significant variation on fluorescence characteristics due to the intermolecular aggregation of rigid segment PF. In the second part of this thesis (chapter 3), the hierarchical self-organized supramolecular materials were prepared from poly[2,7-(9,9-dihexylfluorene)]-block-poly(4-vinylpyridine) (PF-b-P4VP) and 3-Pentadecylphenol (PDP) with different PDP content by hydrogen bonding. The FTIR experimental results showed that hydrogen bonding existed between the nitrogen of 4-vinylpyridine ring and hydroxyl group of PDP. After the PDP was added, the morphologies changed to disorderly cylinder, cylinder-sphere complex and sphere with a domain size of approximately 15-20 nm. The fluorescence characteristics also varied with the diverse hierarchical structures. In the PL spectra, the decrease in the intensity of PF excimer was obtained, as the P4VP(PDP)x matrix content increased. It is the result of the inhibition of the intermolecular aggregation of PF blocks.