(I) 可拉伸之聚矽氧烷-醯亞胺高分子合成及其於軟性電子元件之應用 (II) 具有生物來源軟鏈段之嵌段共軛高分子合成及其於電子元件之應用

(I) Development of Stretchable Poly(siloxane-imide)s and Their Applications in Soft Electronic Devices (II) Synthesis of Bio-based Block Copolymers with Conjugated Segments and Their Applications in Electronic Devices

徐立哲(Li-Che Hsu)

指導教授 ： 陳文章

共同指導教授 ： 佐藤敏文(Toshifumi Satoh)

國立臺灣大學/工學院/高分子科學與工程學研究所/博士(2021年)

https://doi.org/10.6342/NTU202103564

摘要

可拉伸高分子材料由於具備無機材料所欠缺的結構延展性，及可調控之電氣性質，近年來被廣泛應用於開發軟性及穿戴式電子元件。本論文的第一部分(章節一至章節四)介紹可拉伸型聚醯亞胺之高分子結構設計。聚醯亞胺由於其高熱穩定性及溶劑可加工性，被廣泛應用於有機電子元件之基材、介電層與記憶體層。然而，先前研究所報導的聚醯亞胺元件皆僅具備可撓曲性質，至今尚未被拓展至可拉伸元件。第二章介紹可拉伸之聚矽氧烷-醯亞胺高分子。市售的二酸酐單體及具備不同長度矽氧烷軟鏈段之二胺被用於合成一系列之聚(矽氧烷-醯亞胺)高分子。其中，ODPA–A12 聚(矽氧烷-醯亞胺)受益於4,4’-氧雙鄰苯二甲酸酐之柔軟結構以及較短的矽氧烷軟鏈段，展現良好之機械性質例如32.8% 之斷裂伸長量及1.60 MPa之楊氏模數，同時具備良好之溶劑可加工性。因此，該高分子薄膜被應用於製作可拉伸且非揮發性之阻抗型記憶體之記憶體層。延續前一章的結構設計，第三章引入具有三官能基的1,3,5-三(4-氨基苯氧基)苯作為交聯劑，形成聚(矽氧烷-醯亞胺)網狀高分子。藉由調控網狀結構之交聯度，聚矽氧烷-醯亞胺材料可達到超過400%之斷裂伸長量、13.29 MJ M-3之韌性和極佳的形變回復力，且同時具備高於200 °C之軟化溫度。該彈性體作為基材及薄膜皆展現良好耐拉性，展現其極高潛力應用於可拉伸元件。此高分子成功與導電高分子結合，開發出高達100%可拉伸且溶劑可加工之阻抗式記憶體及有機場效電晶體。此部分研究展現高分子結構設計可優化聚矽氧烷-醯亞胺之機械性質，並成功將該材料應用於溶劑可加工且高拉伸性之高分子元件。
本論文的第二部分(章節五至章節八)介紹引入生物來源軟鏈段所合成之嵌段型共軛高分子。生物來源之聚丁位癸内酯軟鏈段與典型的共軛高分子結合形成嵌段型高分子，以提升半導體材料之生質含量及可拉伸性。第六章介紹利用聚丁位癸内酯及聚3-己基噻吩合成之軟–硬–軟三嵌段高分子應用於有機場效電晶體之半導體層。三嵌段結構確保聚3-己基噻吩主鏈之堆疊形成電荷傳輸通道，而分支狀軟鏈段成功調控高分子的結晶度以及相分離，形成高電洞遷移率(4.5×10-2 –8.9×10-2 cm2 V-1 S-1)及高拉伸性的半導體高分子材料。其中，B3AB3型高分子(A：聚3-己基噻吩、B：聚丁位癸内酯)具備最優異之拉伸性，在被拉伸至100%時仍可維持72–75%之電洞遷移率，並可通過500次50%之循環拉伸測試。第七章介紹利用聚丁位癸内酯及聚9,9-雙己基茀合成之雙嵌段共軛高分子，此類高分子被用於電晶體式記憶體之電荷儲存層。受益於聚丁位癸内酯之軟鏈段，AB、AB2及AB3型高分子(A：聚9,9-雙己基茀、B：聚丁位癸内酯)之薄膜皆可承受100% 之應變而不產生裂痕。此外，利用電腦軟體分析原子力顯微鏡相圖，可量化計算聚茀結晶於高分子薄膜之覆蓋面積，並建立電荷儲存密度–薄膜表面型態之關聯性。隨著軟鏈段的分支數增加，高分子形成更高密度的聚茀結晶，達到優化之記憶體元件表現。AB3型高分子具備最佳的記憶體表現(memory window = 108V)，且可承受100%之拉伸並通過500次50%之循環拉伸測試。此部分研究成功將生物來源脂肪族聚酯與共軛高分子結合生成高生質含量之軟性半導體材料，並展現嵌段高分子之構型設計可優化其機械及電氣性質。

關鍵字

拉伸電子元件 ； 聚(矽氧烷-醯亞胺) ； 聚丁位癸内酯 ； 嵌段共軛高分子 ； 有機場效電晶體 ； 記憶體

並列摘要

In the development of soft and wearable electronics, stretchable polymer materials have drawn extensive research attentions due to its superior mechanical properties against inorganic materials, and tunable electronic properties through chemical structure design. In the first part of this dissertation (chapter 1 to chapter 4), I present the development of intrinsically stretchable polymer material based on poly(siloxane-imide)s (PSIs). Owing to outstanding thermal and mechanical properties, polyimide materials have widely been used as memory element, dielectric, and substrate for flexible organic electronic devices. However, no report on stretchable polymers and their device applications can be found due to the rigid polymer backbone of the conventional polyimides. In chapter 2, aminopropyl-terminated polydimethylsiloxanes with different siloxane chain length were polymerized with commercial anhydrides to create a series of PSIs. The synthesized PSIs exhibit tunable mechanical properties according to the structure of dianhydride and the chain length of siloxane diamine. ODPA–A12 synthesized by 4,4-Oxydiphthalic anhydride (ODPA) and aminopropyl terminated polydimethylsiloxanes with a shorter siloxane chain length (DMS–A12) shows optimal mechanical properties including Young’s modulus of 1.60 MPa and the elongation at break of 32.8%. Moreover, the PSIs are soluble in common organic solvents, which is beneficial for developing solution-processed and stretchable electronics. The resistive memory devices based on the PSI thin-film memory layer were fabricated, and the device comprising the ODPA–A12 thin film shows stable write-once-read-many (WORM) type behavior under up to 40% strain and could endure 600 stretch-release cycles at 20% strain. In chapter 3, we further introduce 1,3,5-triaminophenoxybenzene (TAB) as a crosslinker to create a series of PSI networks with elevated toughness and durability. By controlling the amount of TAB crosslinker, the optimal PSI network (PSI-4) shows favorable mechanical and thermal properties including an elongation at break over 400%, a superior toughness at 13.29 MJ M^-3, small hysteresis, and a softening temperature over 200 °C. The designed polymer is highly stretchable and durable both in the bulk and thin-film state, which can be used as both the substrate and thin-film active layer for stretchable electronics. Finally, stretchable and all-solution processed thin-film devices including resistive memory and organic field-effect transistor (OFET) were fabricated with favorable performance under up to 100% strain, and after 500 stretch–release cycles at 60% strain. The results manifest the importance of polymer structure design on manipulating physical properties of PSI, and show great potential for the PSIs on developing solution-processable and stretchable electronics.
In the second part of this dissertation (chapter 5 to chapter 8), I present the bio-based and stretchable semiconducting polymers with branched soft segments of poly(δ-decanolactone) (PDL). PDL was chose as the building block for conjugated–insulating block copolymer (BCP )to raise the bio-based content as well as stretchability of the semiconductor. To synthesize the designed polymers, linear or branched PDLs were connected with the standard conjugated polymers including poly(3-hexylthiophene) (P3HT) and poly(9,9-di-n-hexyl-2,7-fluorene) (PF). In chapter 6, soft–hard–soft type triblock copolymers with P3HT and the branched PDL segments are designed to enhance stretchability of BCP without sacrificing charge mobility. The AB, AB2, B2AB2 and B3AB3 type polymers (A: P3HT, B: PDL) exhibit competitive OFET mobility of 8.8×10^-2, 8.5×10^-2, 8.9×10^-2 and 4.5×10^-2 cm^2 V^-1 s^-1, respectively. Moreover, stretchability of the BCP increases as introducing soft–hard–soft structure and the branched soft segments, which can be attributed to the more random phase separation and smaller P3HT crystallites. Finally, OFETs with the stretched and transferred semiconducting layer of the BCPs were fabricated, and the B3AB3 device shows the highest mobility retention among all the BCPs (72%–75%) at 100% strain, and 71–75% mobility retention after 500 stretch–release cycles at 50% strain. In chapter 7, poly(9,9-di-n-hexyl-2,7-fluorene)-block-poly(δ-decanolactone)s (PF-b-PDLs) with AB, AB2 and AB3 structure (A: PF, B: PDL) were designed as the stretchable charge-storage layer of OFET memory device. Owing to the incorporated PDL soft segments, the BCP thin films are highly stretchable without crack formation under up to 100% strain. Meanwhile, the trapping density of the branched BCP films is boosted by the tailored phase separation and higher crystallinity of the BCPs. As a result, the OFET memory comprising the PF-b-PDL3 electret exhibits the largest memory window (102 V) and the highest memory ratio (3.5 × 10^4). The device can be stretched to 100% with good performance, and shows 84% memory window retention after 500 stretch–release cycles at 50% strain. These results prove the feasibility of making stretchable semiconductor with the bio-based aliphatic polyester, and highlight the importance of architecture design on modulating electronic properties and stretchability of conjugated BCP.

並列關鍵字

stretchable electronics ； poly(siloxane-imide)s ； poly(δ-decanolactone) ； conjugated block copolymers ； organic field-effect transistor ； memory device

參考文獻

(I) Development of Stretchable Poly(siloxane-imide)s and Their Applications in Soft Electronic Devices:

1. M. T. Bogert and R. R. Renshaw, J. Am. Chem. Soc., 1908, 30, 1135-1144.

2. W. Edwards and I. Robinson, US Pat, 1955, 2712543.

3. Q.-H. Lu and F. Zheng, in Advanced Polyimide Materials, Elsevier, 2018, pp. 195-255.

4. C. Sroog, A. Endrey, S. Abramo, C. Berr, W. Edwards and K. Olivier, J. Polym. Sci. A., 1965, 3, 1373-1390.