以兩性高分子為模板並利用有機矽烷造成介尺度 結構轉變以及應用於金屬離子的偵測

Mesophase Transition in the Organosilicate Templated by Amphiphilic Block Copolymers and Their Applications for Metal Ion Sensors

劉易昌(Yi-Chang Liu)

指導教授 ： 劉緒宗

國立臺灣大學/理學院/化學研究所/博士(2008年)

https://doi.org/10.6342/NTU.2008.01065

摘要

論文摘要
本篇論文是以polyethyleneglycol methyl ether為起始物來合成醯胺連結的巨起始劑，再利用原子轉移方式自由基聚合(atom transfer radical polymerization, ATRP)合成出疏水端為methyl acrylate的兩性雙區塊共聚高分子EO45MA40、EO45MA53以及EO45MA63。
利用所合成的雙區塊聚合物在酸性水溶液下，TEOS為矽的來源，進行孔洞性材料的合成，其孔徑(pore size)隨疏水端的增長而增大，所得結構皆為立方體(Im m)。以七種有機矽烷分別與TEOS進行共縮合反應，會得到介尺度結構(mesostructure)改變的孔洞性材料，例如具有六角柱狀結構的M45-40CPTMS(10%)-E、M45-40MPTMS(10%)-E、M45-40PTMS(10%)-E、M45-40VTCS(20%)-E、M45-53MPTMS(5 %)-E、M45-53 PTMS(5 %)-E、M45-53VTCS(5 %)-E、M45-53MPTMS(10 %)-E和M45-53VTMS(10 %)-E以及一些具有立方體與六角柱狀混合結構或非結晶性結構的材料。這些有機矽烷分別為cyclopenadienylpropyltriethoxysilane (CPDEPTES)、3-chloropropyltrimethoxy- silane(CPTMS)、3-mercaptopropyltrimethoxysilane (MPTMS)、octyltriethoxysilane (OTES)、phenyltrimethoxysilane(PTMS)、vinyltrichlorosilane (VTCS)、vinyl- trimethoxysilane (VTMS)。
利用M45-53MPTMS(10%)-E架接MPTMS形成M45-53MPTMS(10%)-g-MPTMS，並以此為起始物合成含硫取代基isoindole的材料M1，作為金屬離子偵測器。對14種離子作吸附反應的結果之中，IA、IIA離子樣品使得螢光增強，3d、4d、5d金屬離子樣品則會淬熄螢光，其中以CuCl2和Pb(ClO4)2的樣品淬熄效果最好。
M1在pH值 ＞ 6.95之下螢光迅速增強，pH值介於3.06-6.95之間時改變不大，而pH值 ＜ 3.06時則有顯著的淬熄；在pH = 7的緩衝溶液下對離子吸附，IIA離子樣品螢光增強程度減緩，其餘的離子樣品螢光改變不大。在吸附時若加入acetylacetone當共配位基，螢光淬熄的程度有減緩現象。此外具有不同於M1取代基的材料M2，對金屬離子吸附之螢光變化情形則與M1樣品相差不多。有機化合物含硫取代isoindole G對離子的結合，只有CuCl2對G完全淬熄，其餘的樣品幾乎沒有改變。這些現象可用軟硬酸鹼(hard soft acid base)理論解釋：M1上含硫取代isoindole上的硫原子與過渡金屬離子結合力較佳的話，會造成較大程度的螢光淬熄。
由於isoindole為一個溫度敏感的化合物，在室溫下即會氧化，所以改用對溫度穩定的anthracene基團。將anthracene基團連接在含有硫原子的M45-53MPTMS(10%)-E上，形成另一金屬離子偵測器M3，對前述的14種離子進行檢測，其中以Cu2+使M3的螢光萃熄程度最強，並且由於M3對銅離子吸附能力極佳，可應用為清除水中銅離子材料。在M3 系統中，利用中性乙二胺水溶液沖洗可以將銅離子脫附，回覆成原來的M3。經過八次脫附後，anthracene仍保留在M3之中，使得此材料可以重覆吸附脫附使用。

關鍵字

介尺度結構 ； 離子偵訊器 ； 兩性高分子 ； 螢光 ； 中孔洞

並列摘要

Abstract
Utilizing the diblock copolymers (EO45MA40, EO45MA53, and EO45MA63 ) as tmplates, porous materials having cubic Im m structure could be obtained under acidic conditions with TEOS as silicate sources and the pore diameter increased accordingly with the chain length of polyacrylate. However, the meso-structures of silicas changed from cubic to other structures upon the addition of organosilanes with the co-condensation of TEOS. The organosilanes used here include cyclopenadienylpropyl- triethoxysilane (CPDEPTES), 3-chloropropyltrimethoxysilane (CPTMS), 3-mercapto- propyltrimethoxysilane (MPTMS), octyltriethoxysilane (OTES), phenyltrimeth- oxysilane (PTMS), vinyltrichlorosilane (VTCS), vinyltrimethoxysilane (VTMS). The obtained silica with hexagonal structure were from M45-40CPTMS(10%), M45-40MPTMS(10%), M45-40PTMS(10%), M45-40VTCS(20%), M45-53MPTMS(5 %), M45-53 PTMS(5 %), M45-53VTCS(5 %), M45-53MPTMS(10 %) and M45-53VTMS(10 %), whereas other compositions provide mesostructural silica in either a mixed phase of cubic and hexagonal, or amorphous.
In order to increase the content of thiol groups, M45-53MPTMS(10%)-E was further treated with MPTMS to yield M45-53MPTMS(10%)-g-MPTMS. This grafting material was subsequently modified with a isoindole functionality to form material (M1), which was used for the detection of metal ions through the isoindole fluorescent receptor. While enhanced fluorescence was observed upon the addition of IA and IIA metal ions, the transition metal ions (3d, 4d and 5d) caused the quenching. Among all ions, CuCl2 and Pb(ClO4)2 resulted in a dramatic fluorescent quenching.
The fluorescence phenomenon in M1 system depended on the pH of the medium and was strongly enhanced as pH > 6.95 and quenched as < 3.06, respectively, but it showed insignificant change in the pH range of 3.06 ~ 6.95. In a buffer solution of pH = 7, M1 adsorbed with IIA metal ions showed a slightly enhanced fluorescence, but other ions did not show substantial effect. For the substituted isoindole chromophore M2, comparable to M1, proved a similar fluorescent behavior. Completely fluorescent quenching was observed upon the treatment of CuCl2, but no change for other ions. These phenomena described above could be rationalized by HSAB theory, which a stronger interaction between sulfur and transition metal ions resulted in greater fluorescent quenching.
Due to the thermal unstable nature of isoindole, anthracenyl group was introduced for further application. Thus, modification of M45-53MPTMS(10%) with chloromethylanthrance yielded M3. It turned out that M3 could behave a good absorbent to remove Cu2+ ions from water. This material could be re-used for removal of metal ions. Thus, the absorbed Cu2+ was completely washed out by the treatment of an aqueous solution of ethylenediamine under neutral conditions, and the regenerated M3 appeared to remain the same activity even after eight runs.

並列關鍵字

mesostructure ； mesoporous silicate ； metal ion sensor ； Amphiphilic Block Copolymers ； organosilane ； fluorescence

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