苯乙烯馬來酐共聚物接枝聚醚胺之梳狀形高分子合成 及其環境應答與自我排列性質

Abstract

本論文以苯乙烯馬來酐之共聚物(poly(styrene-co-maleic anhydride)接枝不同結構之聚醚胺鏈段所合成之梳狀形高分子(SMA-POP)為研究主軸，研究分為三個章節，分別探討SMA-POP之(1)溫度應答及其形態變化(2)酸鹼應答及其型態變化，以及(3)利用此系列高分子作為樣板促使銀離子排列並還原為銀線 Chapter 1. Temperature- and pH-Responsive Properties of Oligo-(oxypropylene) - Amine Graft Poly(Styrene-co-Maleic Anhydride) 研究利用具有不同比例苯乙烯與馬來酸酐之共聚物做為主鏈，配合具有氫鍵之聚醚胺鏈段poly(oxypropylene)-diamines (POP-amine)合成一系列具有溫度與酸鹼應答性質之梳狀形高分子，藉由調整支鏈POP鏈段與主鏈styrene的比例可得Lower critical solution temperature (LCST)從11- 49 oC，高分子之溫度轉換亦受pH所影響。由原子力顯微鏡(TM-AFM)可觀察到此高分子於相轉換溫度前後的聚集情形。

Chapter 2. Stimuli-Responsive Micelles from Comblike Copolymers of Poly (Styrene-co-Maleic Anhydride) Graft Poly(oxypropylene)-Amines 延續上一章所提及所合成之SMA3000-POP400鏈段上帶有-COOH,-CH2CH(CH3)O-, -NH2, -CONH- 與 aromatic group等官能基，使得SMA3000-POP400除具有溫度應答之特性外，亦於不同酸鹼環境下具有不同之形態。藉由zeta potential 分析可得知高分子表面帶電性質為控制高分子微胞之尺寸與微胞形態之重要因素。隨pH 從10至3.5而表面電性由-31 mV增加至29 mV，亦藉由TEM分析得知高分子從random coil, micelle, nanoparticles直至inversed micelle. 微胞結構之變化亦表現在薄膜材料上，將不同pH值下所製備的薄膜可由親水性變為親油性。

Chapter 3. Hierarchical Self-Assemblies of Silver Rectangles and Fibrous Wires by Copolymer Templates and Visible-Light 支鏈為polyoxyalkylene 之梳狀形高分子具有螯合及穩定金屬離子之作用，配合高分子SMA2000-M2070製作奈米銀粒子的過程發現，緩慢的光環原方式可以使得銀粒子在高分子的作用下排列為銀線，此一線狀材料由寬0.6 - 1μm長0.4μm之不規則四邊形所堆積排列而成，長、寬可達370μm × 6.4μm。主要組成：銀佔95wt% (80 mole%)。同時具有良好之導電性(170 S/cm)，並可進一步藉由升溫至250 oC將各線材融熔接著，將導電度再提升至910 S/cm.

In this article, copolymer oligo-(oxypropylene) - amine graft poly(styrene- co-maleic anhydride) is prepared by various structure. The synthesized comb-branched copolymer is stimuli responsive and could be used as a polymer template for preparing silver fiber by self-assembly. There are three chapters to describe the (a) temperature responsive, (b) pH responsive and (c) the self assembly behavior of these series of comb-branched copolymer. Chapter 1. Temperature- and pH-Responsive Properties of Oligo-(oxypropylene) - Amine Graft Poly(Styrene-co-Maleic Anhydride)

A series of temperature- and pH-responsive copolymers were synthesized by grafting poly(oxypropylene)-diamines (POP-amine) onto poly(styrene-co-maleic anhydride) (SMA). Owing to the presence of multiple POP-pendants and their expressive hydrogen bonding properties, the copolymers in water exhibited Lower Critical Solution Temperature (LCST) behavior in the range of 11-49 oC depending on the POP segmental weight and the SMA backbone structures. Furthermore, the co-existence of -NH2 termini and amidoacid functionalities rendered the copolymers responsive to environmental pH changes. Structural variation in the SMA backbone, particularly the monomer ratio of styrene to maleic anhydride, POP length, and amine multiplicity, may significantly alter the shapes of copolymer aggregation in responding to the environmental pH and temperature. The responsiveness was observed on their morphological changes by tapping mode atomic force microscopy (TM-AFM) on mica film surface and also fluorescent properties in aqueous solution. Chapter 2. Stimuli-Responsive Micelles from Comblike Copolymers of Poly (Styrene-co-Maleic Anhydride) Graft Poly(oxypropylene)-Amines

The pH-responsive micellization of the copolymers, prepared from the grafting reaction of poly(oxypropylene)-amine of 400 g/mol molecular weight (POP400) onto poly(styrene-co-maleic anhydride) (SMA) backbone, is presented. The comb-branched copolymers are consisted of oligo-styrene/ethylene in the backbone and amide-linkages with polar pendants of carboxylic acid, oxylpropylene-segment, and primary amine. The co-existence of –COOH and –NH2 in multiplicity rendered the SMA-POP copolymer responsive to pH and temperature. Conformational changes from random coil at pH 10 to spherical micelle with an average 50 nm diameter at pH 8.3 were observed by particle size analysis in water at ambient temperature. At the isoelectric point (IEP pH 8.2) of SMA3000-POP400, the polymer self-assembled into spherical polymer particles with the diameter range from 100 to 500 nm and stable after removing waters. In forming film, the surface exhibited different hydrophilic/hydrophobic properties, demonstrating the surface contact angle of 23o at pH 9.3 and 58o at pH 8.1. Inversion of micellar formation, depending the pH environment, through the non-covalent bonding of SMA backbone aggregation and water interaction with the pendent COOH and NH2 is proposed.

Chapter 3. Hierarchical Self-Assemblies of Silver Rectangles and Fibrous Wires by Copolymer Templates and Visible-Light We observed the self-assemblies of silver rectangles and fibrous wires from silver nitrate reduction in the presence of copolymer template and visible-light. The copolymer in comb-like structure was facilely prepared from the grafting reaction of poly(oxyalkylene)-monoamine (POA-amine) onto the poly(styrene-co-maleic anhydride) (SMA). By dissolving AgNO3 in the aqueous copolymer and standing for days under visible light, unique formation of rectangle-shaped silver wires in the dimension of 1.6-6.4μm in diameter and 100-370μm in length was obtained. The formation process was monitored by UV-visible spectroscopy, particle size analysis, scanning electron microscope (SEM) and transmission electron microscope (TEM), showing first appearance of silver particles is 10 nm in diameter, followed by the intermediate rectangles (0.6-1.0 μm in width and 0.4 μm in length) and ultimately the precipitated micrometer wires. The growth of the precipitated silver fibers was accelerated by the exposure of visible light as the photo-reducing energy source. The microscale fibers are characterized to have silver content over 95 wt % (80 mole %) and with the conductivity of 170 S/cm.