聚噻吩硬桿-柔軟嵌段高分子之合成及特性研究

Synthesis and Characterization of Poly(3-hexyl thiophene) Based Rod-Coil Block Copolymers

鄭詩慈(Shih-Tzu Cheng)

指導教授 ： 陳文章

國立臺灣大學/工學院/化學工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.00882

摘要

硬桿-柔曲嵌段共聚物(rod-coil block copolymers)由於能藉由改變其表面形態來產生不同的功能應用，所以在近年來受到廣泛的研究與討論。以共軛高分子為主體的嵌段共聚物能經由溶劑性質與與固態堆積來改變其電子與光電特性。舉例來說，polyquinoline-polystyrene嵌段共聚物在其吸收與發光特性被改變時，亦具有不同的表面形態。在近幾年來，在嵌段共聚物中導入poly(3-hexyl thiophene)之硬桿-柔曲嵌段共聚物所形成的奈米導線材料亦開始被探討研究。然而，像是親水鏈段、溶劑性質與製程溫度對具有共軛與雙親性高分子鏈嵌段共聚物所產生的效應尚未有詳細而完全的研究。

在本研究中，主要對於具有聚噻吩共軛鏈段之雙親性的硬桿-柔曲嵌段共聚物的合成、表面形態與性質做探討，並可將本研究目的分為三大部分：(1) 以原子轉移自由基聚合法來製備三種含有聚噻吩共軛鏈段之雙親性的硬桿-柔曲團聯共聚物，分別是具有PMMA,PAA 與PMSMA三種不同親水柔曲鏈段。(2)觀察P3HT, (P3HT)47-b-(PMMA)748, (P3HT)47-b-(PAA)93 與(P3HT)47-b-(PMSMA)34在溶液中的表面形態和性質並探討不同性質溶劑對含有poly(3-hexyl thiophene) 之硬桿-柔曲嵌段共聚物的表面形態與光物理性質的影響。(3)觀察P3HT, (P3HT)47-b-(PMMA)748, (P3HT)47-b-(PAA)93 與(P3HT)47-b-(PMSMA)34之固態性質，並對於含有poly(3-hexyl thiophene)硬桿鏈段之嵌段共聚物的morphology與光物理性質在不同溫度下的變化做探討。
根據TEM的結果顯示，藉由不同溶劑(甲苯/甲醇)性質的比例，(P3HT)47-b-(PMMA)748, (P3HT)47-b-(PAA)93 與 (P3HT)47-b-(PMSMA)34 在溶劑中能具有不同的表面形態，像是柱狀、球狀、車輪狀和微胞結構(LCMs)。由於聚噻吩在甲醇中會產生聚集的情形，故可用來解釋上述所得到的結果。此外，由於聚噻吩在甲醇中會產生聚集的原因，造成含有poly(3-hexyl thiophene)硬桿鏈段之團聯共聚物的吸收與發光波長會隨著不同的性質的溶劑比例而產生紅移的現象。(P3HT)47-b-(PMMA)748, (P3HT)47-b-(PAA)93 和(P3HT)47-b-(PMSMA)34薄膜的表面形態與光物理性質在不同固化溫度下，會產生明顯的改變。當提高不同固化溫度時，含有poly(3-hexyl thiophene) 之硬桿-柔曲團聯共聚物的吸收與發光波長會產生藍移的情形，這可能是因為在主鏈段上的聚噻吩環鏈段產生不規則運動引起的共軛鏈段變短所造成的結果。
故由本研究目前的結果得知，不同溶劑性質的比例與固化溫度可對含有poly(3-hexyl thiophene) 之硬桿-柔曲團聯共聚物的表面形態與光物理性質產生一定的影響與改變。

關鍵字

聚噻吩 ； 硬桿-柔軟嵌段高分子

並列摘要

Rod-coil block copolymers have been extensively studied recently since they offer the opportunities of tuning the morphologies and the resulted functionalities. Conjugated polymer based rod-coil block copolymers could tune the electronic and optoelectronic properties through the solvent quality or solid-state packing. For example, polyquinoline-polystyrene block copolymers could have various kinds of morphologies with tunable optical absorption or photoluminescence properties. Nanowires obtained from poly(3-hexyl thiophene)–coil block copolymers was also discovered recently. However, the effects of hydrophilic coil segment, solvent quality or processing temperature on the conjugated rod-coil block copolymers have not been fully explored yet.
In this thesis, synthesis, morphologies and properties of polythiophene based rod-coil block copolymers are reported. There are three parts of this thesis as shown below: (1) Synthesis of poly(3-hexyl thiophene) (P3HT) based rod-coil polymers by atom transfer radical polymerization. Three kinds of hydrophilic coil segments were employed, including poly(methyl methacrylate), poly(acrylic acid), and poly(3-(trimethoxysilyl)propyl methacrylate). The P3HT macroinitiator was synthesized first and then the coil segment was prepared using atom transfer radical polymerization. (2) Morphologies and properties of P3HT, (P3HT)47-b-(PMMA)748, (P3HT)47-b-(PAA)93 and (P3HT)47-b-(PMSMA)34 in solutions. The effects of good/poor solvent ratio on the morphologies and photophysical properties of the synthesized polymers were investigated. (3) Morphologies and properties of P3HT, (P3HT)47-b-(PMMA)748, and (P3HT)47-b-(PMSMA)34 in solid state. The effects of processing temperature on the morphologies and photophysical properties of the synthesized polymers were investigated.
The TEM results suggest that various morphologies of the (P3HT)47-b-(PMMA)748, (P3HT)47-b-(PAA)93 and (P3HT)47-b-(PMSMA)34 could be obtained by varying the good solvent toluene /poor solvent methanol ratio, including cylinder, sphere, vesicle, and large compound micelles (LCMs). The aggregation of the P3HT segment in the poor solvent of methanol explains the above result. Such aggregation led to a significant red shift on the optical absorption and photoluminescence spectra of the P3HT-coil block copolymers by increasing the methanol content in mixed solvents. The morphologies and photophysical properties of the (P3HT)47-b-(PMMA)748, (P3HT)47-b-(PAA)93 and (P3HT)47-b-(PMSMA)34 films were also significantly varied by the curing temperature. Blue shifts on the optical absorption and photoluminescence spectra of the P3HT-coil block copolymer film were observed by increasing the curing temperature. It is probably because the degree of twisting thiophene rings is increased by increasing the curing temperature. Thus, a coiled polythiophene chain with shorter conjugation lengths is obtained, which explains the variation of the photophysical properties with curing temperature.
The present study suggests that the morphologies and photophysical properties of the P3HT-coil block copolymers could be significantly tuned by the solvent quality or curing temperature.

並列關鍵字

Poly(3-hexyl thiophene) ； Rod-Coil Block Copolymers

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