氫鍵對電子高分子混摻薄膜及靜電紡絲纖維結構形態和特性之影響

Effects of Hydrogen Bonding on the Morphology and Properties of Electronic Polymer Blending Films and Electrospun Fibers

曾尹澤(Yin-Tse Tseng)

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(2019年)

https://doi.org/10.6342/NTU201903840

摘要

近年來，軟性可拉伸式元件作為次世代穿戴式裝置而蓬勃發展，因此受到學界廣泛的關注。在高機械強度形變下，同時保有其光電性質及效能之拉伸式元件，可應用於開關電路、顯示器、感測器及能源轉換等領域，大幅提高未來人類的生活品質。拉伸式導電電極及發光材料是其中兩大核心發展技術，可應用於多種拉伸式元件中。在可拉伸之導電材料中，因PEDOT:PSS具有有機溶劑可調控之高導電度、高分子鏈本身之拉伸性及與軟性高分子混摻之相容性，許多研究致力於PEDOT:PSS之元件開發。可拉伸式發光層目前則主要藉由包埋無機量子點(QD)或螢光共軛高分子製造，然而，因為有機發光小分子缺乏良好的分散系統，其極少被研究應用於可拉伸式發光層中。另一方面，混摻系統內氫鍵作用力對微結構、光電性質及拉伸性質的影響，也很少被研究及考慮。對此，本論文提出兩個高分子混摻系統，研究氫鍵作用力對電子高分子混摻薄膜和電紡纖維之微結構和特性之影響，研究重點分述如下：
本文的第一部分(第二章)，藉由PEDOT:PSS與PVA、PAA、PMAA進行混摻，研究不同氫鍵作用力，對微結構及物理性質的影響，做為未來PEDOT:PSS應用之依據。利用Gaussian模擬從理論上證實提出之氫鍵強度差異，並利用導電AFM從微結構上支持此強度差異造成的影響。更進一步研究以甲醇處理改質後，微結構、導電度及拉伸性上的顯著變化及它們之間的關係，並將軟性高分子對甲醇溶解度差異納入考慮。最後，將甲醇改質後之PEDOT:PSS/PAA (20/80)薄膜應用於壓力感測器中，其於20%拉伸狀態下，擁有39.90 kPa-1之高感測度。另外，PEDOT:PSS/PAA之大面積靜電紡絲纖維，可以達到比薄膜更高的拉伸性，極具未來應用潛力。
本文的第二部分(第三章)，藉由簡單混摻PAA與螢光素或羅丹明B，開發出利用氫鍵作用力達到良好分散的全有機小分子系統，其同時具有高亮度的螢光及拉伸性。調整螢光素及羅丹明B的比例可產生綠色至深橙色的顏色變化，而引入PDMS-OH則可更進一步提高拉伸性。同時混摻螢光小分子及PDMS-OH，調整光色的性質及拉伸性的提升不會互相影響，因此可成功製作出在FL1/PAA-1’至FL0.7RB0.3/PAA-1’混摻比例下，擁有25%-30%發光效率的薄膜及纖維；纖維之斷裂應變為100%，薄膜則甚至可承受620%之拉伸應變。最後，利用螢光顯微鏡探究發光亮度與螢光小分子相容程度之間的關係，以突顯氫鍵造成的分散性對此系統的重要性。此兼具高亮度及拉伸性之混摻系統，未來同樣極具應用潛力。
綜上所述，本論文提出一個新的研究觀點，將氫鍵作用力對性質的影響納入考慮，製作可拉伸之導電及發光材料，未來可激發出新的設計方法且可應用於拉伸式電子元件中。

關鍵字

高分子混摻 ； 氫鍵作用力 ； 微結構 ； 發光材料 ； 可拉伸式元件 ； 靜電紡絲

並列摘要

In recent years, stretchable electronics have been regarded as next generation wearable devices and attracted extensive attention. These devices retaining their electronic performances under a high mechanical deformation can be applied in switches, displays, sensors, and energy conversion regions, improving our daily life in the future. For stretchable electronics, stretchable electrode and emissive materials are the two key techniques to be developed. Among stretchable electrode materials, many efforts devoted in poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) since its tunable high conductivity by solvents, intrinsic stretchability, and compatibility with other soft polymers. Stretchable emissive layers were mainly fabricated by embedded inorganic quantum dots (QD) or emissive conjugated polymers. However, small molecular dyes were rarely studied due to the lack of well dispersion in the blending systems. The roles of hydrogen bonding interaction were not thorough investigated yet as well. In this thesis, two blending systems containing hydrogen bonding interaction were explored to investigate their effects on the properties and morphology of electronic polymer blends, as described in the following:
1. Morphology and Properties of PEDOT:PSS/Soft Polymer Blends through Hydrogen Bonding Interaction and Methanol Post Treatment (Chapter 2): The hydrogen bonding interaction between PEDOT:PSS and polyvinyl alcohol (PVA), poly(acrylic acid) (PAA), and poly(methacrylic acid) (PMAA) were investigated to explore their effects on the microstructures and properties. Gaussian simulations and conductive-atomic force microscope (C-AFM) were utilized to support the hydrogen bonding strength effects from the theoretical and morphological aspects. The correlations between the morphology, conductivity and stretchability significantly changes after the methanol treatment were studied as well, in which the solubility of the soft polymers in methanol was considered. Finally, PEDOT:PSS/PAA (20/80) thin film was applied to pressure sensor device, which had 39.90 kPa-1 sensitivity at the 20% tensile strains operation. Large scale fiber mat was fabricated to demonstrate the application potential as well.
2. New Stretchable and Multicolor Emissive Materials Based on Dyes/Polymer Blending System through Hydrogen Bonding (Chapter 3): All organic basis blending system was exploited simply containing PAA and fluorescein, achieving the goals of highly emission and stretchability. The emission color was tunable from green to deep orange region by changing the ratios of fluorescein/Rhodamine B. Also, by blending with bis(silanol)-terminated poly(dimethyl siloxane) (PDMS-OH) could further increase the stretchability. The elongation of the PDMS-OH blended film and fiber mat at break were around 620% and 100% tensile strains, respectively. The blends of PAA, PDMS-OH, and dyes showed the color-tuning characteristics and the luminescence was largely maintained under stretching. The quantum yields were around 25% to 30% in the FL1/PAA-1’ to FL0.7RB0.3/PAA-1’ blending films and fibers. The relations between emission and miscibility were revealed by the confocal microscopy. This blending system, with a highly color tunable emission and stretchability properties, is prospective for further luminescent applications.
Our results demonstrated a new aspect of hydrogen bonding on the morphology and properties of stretchable conductive or luminescence films and electrospun fibers, which may promote other new fabrication strategies in stretchable electronics.

並列關鍵字

polymer blends ； hydrogen bond ； morphology ； dye ； stretchable devices ； electrospinning

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