含聚3-丁基噻吩與聚異戊二烯的嵌段共聚高分子之合成與物性之研究

Abstract

我們將poly(3-butylthiophene)(P3BT)的末端基改質成醛基(P3BT-CHO)、再將此P3BT-CHO加入帶有活性陰離子之polyisoprene(PI)，並成功地合成出一系列含有Poly(3-butylthiophene-block-polyisoprene)(P3BT-PI)的雙嵌段共聚高分子。我們將2,5-dibromo-3-butylthiophene(Br2-3BT)使用GRIM聚合法聚合，再將此P3BT之末端基醛化、以產生帶有醛基的P3BT(P3BT-CHO)。我們再以陰離子聚合法、成功聚合出不同分子量之PI， 與P3BT相比，PI具有相當低的玻璃轉移溫度以及更好的溶解度，可以使得P3BT-PI更好溶解在一般的有機溶劑，進而提供更好調整P3BT-PI所製成薄膜之morphology的能力。 我們使用廣角X光散射研究薄膜的結晶行為，發現PI會對P3BT-PI結晶時有些微影響。而從紫外光/可見光光譜可以看到P3BT的π-π stacking並不會隨著PI的加入而有所改變。 在P3BT-PI的電性方面，我們則將嵌段共聚高分子製作成薄膜電晶體(TFT)來觀察水平方向之電洞傳導率。我們可以發現，在接上少量PI時，能夠幫助導電率有些微提升。 PI具有相當柔軟的機械性質，提供了一般共軛高分子原本不具有的可抗變形之能力。我們將P3BT-PI之薄膜進行撓曲，可以期待P3BT-PI能夠具有製作可撓性電子元件之能力。

A series of well-defined poly(3-butylthiophene-block-polyisoprene) (P3BT-PI) diblock copolymers with various compositions were synthesized via effective coupling reaction between aldehyde end-functionalized P3BT (P3BT-CHO) and living polyisoprene anions. P3BT-CHO was obtained from GRIM polymerization of 2,5-dibromo-3-butylthiophene(Br2-3BT) and the following formylation. Living PI anions with different degree of polymerization were obtained from anionic polymerization. Comparing with pristine P3BT, the low Tg and high solubility of PI allowed P3BT-PI to show better solubility in common organic solvents, and the BCPs also provide the feasibility to manipulate the morphology of the thin films. Wide angle X-ray scattering demonstrate that the introduction of PI should has little impact on the crystallization behavior of P3BT in the spin-coating thin film. π-π stacking of P3BT should also retain in the thin films of P3BT-PI according to the UV-Vis spectroscopy. The charge mobility of P3BT-PI thin films were evaluated by the corresponding thin film transistor(TFT) studies, and which depicted that charge transportation in parallel direction could be slightly improved by introducing small amount of PI. The thin film of P3BT-PI also exhibited good flexibility upon blending. It is anticipated that P3BT-PI should be a highly potential candidate for the application in flexible electronics.