製備酸鹼應答型規則樹枝狀分子自組裝蜂窩狀孔洞薄膜於染料吸附應用

Preparation of pH-responsive honeycomb-like film from self-assembled dendritic polymers for dye adsorption

林晏羽(Yen-Yu Lin)

指導教授 ： 鄭如忠

共同指導教授 ： 劉定宇

國立臺灣大學/工學院/高分子科學與工程學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201902545

摘要

本研究利用具反應選擇性之單體4-isocyanato-4’-(3,3-dimethyl-2,4-dioxo -azetidino)-diphenylmethane（IDD）作為構築單元，重複單元逐步反應製備出不同代數末端具十八長碳鏈的poly(urea/malonamides) dendrons規則樹枝狀分子（DG0.5-DG2.5），並經由改質成功製備出一系列焦點端帶有羧基官能基之規則樹枝狀分子（a-DG0.5-a-DG2.5）。亦證明了較高代數（G1.5、G2.5）的低分子量poly(urea/malonamide) dendrons能透過分子間氫鍵為主的作用力進行超分子的自組裝，同時雙親性的小分子dendrons具有穩定有機溶液與水的界面、維持breath figure法所產生之蜂窩狀孔洞結構的能力，可單獨作為製備蜂窩狀孔洞膜之材料。此外，也由一系列的實驗設計，探討不同變因對孔洞型態的影響，並證明透過接上羧基官能基，不只增強了dendrons間的分子間氫鍵作用力，有助於分子的自組裝，更賦予它酸鹼應答的特性。羧基的存在使得薄膜在鹼性環境下能因羧基的去質子化使表面帶負電荷，進而選擇性吸附帶正電的染料分子。本研究透過poly(urea/malonamide) dendrons難以取代的獨特性質，成功製備出具有酸鹼應答性—能選擇性吸附帶正電分子的蜂窩狀孔洞薄膜，可望應用在環境檢測的領域。

關鍵字

breath figure法 ； 規則樹枝狀分子 ； 染料吸附 ； 蜂窩狀孔洞膜 ； 酸鹼應答型材料 ； 超分子自組裝

並列摘要

A series of anionic dendritic polymeric amphiphiles with carboxyl groups at the focal points were successfully prepared through iterative addition reactions. For the self-assembly study, it has been proved that these dendritic amphiphiles can form honeycomb-like structure via breath figure method with relatively small molecular weights of poly(urea/malonamide) dendrons. Due to the presence of hydrogen bonding interactions of malonamide groups, interactions of aromatic moieties, and Van der Waals interactions of long alkyl chains, these dendrons are capable of exhibiting supramolecular self-assembly property, stabilizing the interfaces between water droplets and organic solution to achieve porous ordered arrays. In addition, the effects of different variables such as concentration, relative humidity, the presence of carboxyl groups, and dendron generations on the porous structure were investigated. It is important to note that the attachment of carboxyl groups would enhance the intermolecular hydrogen bonding interactions, leading to the formation of improved hexagonal arrays. Furthermore, with the focal point functionalized with a carboxylic acid group, these dendrons (a-DG1.5, and a-DG2.5) were able to exhibit pH-responsive behavior, which would deprotonate and form negatively charged carboxylate groups under high pH values (e.g., pH 10). Consequently, cationic dye molecules would attach onto the films through Coulomb force under basic conditions. By utilizing the unique properties of poly(urea/malonamide) dendrons, pH-responsive honeycomb-like films with switchable dye adsorption ability were successfully developed.

並列關鍵字

breath figure method ； dendrons ； dye adsorption ； honeycomb-like films ； pH-responsive ； supramolecular-assembly

參考文獻

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