聚三己烷噻吩-聚三噻吩己酸乙酯嵌段式共聚物之合成、物理性質鑑定與型態學研究

Abstract

本論文研究呈現了聚三噻吩-聚三噻吩己酸乙酯(P3HT-b-P3THA) 嵌段式共聚導電高分子之化學合成、光電性質鑑定及結晶型態學研究。GRIM聚合方法，可合成出高位向選擇性(high regioregularity)、低分子量分佈之聚噻吩，更可利用單體及鎳起始催化劑的莫耳比，調整並準確合成出預得高分子之分子量。在UV-Vis測量後，發現具酯類官能機取代側鍊的P3THA，因其側鍊體積較大，影響到主鍊之共平面性，又因酯基為拉電子基，吸收光譜因較短的共振長度而較P3HT藍移約25奈米。在嵌段式共聚高分子中，光譜隨著P3THA鍊段之莫耳比例增加，有線性藍移的趨勢。在CV測量中，可發現嵌段式共聚導電高分子同時具有P3HT及P3THA的氧化、還原峰，表示嵌段式導電高分子可同時存在兩個高分子鍊段的電化學性質。利用DSC、WAXS、GIWAXS以及AFM實驗，探討出此嵌段式共聚導電高分子之結晶結構，隨著嵌段比例之不同而改變。當P3HT鍊段之莫耳比例超過百分之五十時，可觀察到微相分離的現象；當P3HT之鍊段莫耳比低於百分之二十，則可觀察到兩鍊段互溶共晶之共晶結構。因此，我們可利用改變此嵌段式共聚導電高分子之嵌段莫耳比例，調控其結晶結構。此實驗結果為調控嵌段式共聚導電高分子奈米結構之研究領域，提供新穎的調控設計、方式及理念。

The synthesis, characterization and morphology study of copolymers of poly(3-hexylthiophene) (P3HT) and poly(3-thiophene hexylacetate) (P3THA) are performed in this thesis. By using GRIM method, polymers with high regioregularity, narrow polydispersity and controlled molecular weight can be obtained. From the optoelectronic properties characterization, the ester-functionalized P3THA shows a blue-shift UV-Vis spectrum and lower HOMO as compared to P3HT. These results are contributed to the bulky and the electron-withdrawing ester group which decrease the conjugated length. The amount of blue shift is directly proportional to the amount of P3THA in the block copolymer. From the CV measurements, each respective HOMO and LUMO is observed in each block segment of block copolymer which does not present in the random copolymers. The thermal and phase behaviors of the block copolymers were investigated by DSC, WAXS, GIWAXS and AFM. The crystalline morphology of copolymers is dependent on the block compositions of P3HT-b-P3THA. Phase separation is observed as the P3HT block higher than 50% molar ratio. When the molar ratio of P3THA is larger than 80%, the cocrystalline structure is observed. Thus, the crystalline morphology can be tuned by changing the block copolymer compositions. The results are useful for the design and fabrication of nanostructured conducting polymers.