行政院國家科學委員會補助專題研究計畫
■ 成 果 報 告
□ 期中進度報告
由嵌段共聚物製備 CdS 奈米粒子/高孔隙度倍半聚矽氧烷複合膜，及
其微結構和光電特性探討(3/3)
Synthesis of CdS Nanoparticle/ Porous Poly(Silsesquioxane) Composition
Films via Block Copolymers, Their Characteristics of Microstructures and
Optoelectronic Properties (3/3)
計畫類別：■ 個別型計畫 □ 整合型計畫
計畫編號：
NSC93-2218-E002-064
執行期間：93 年 8 月 1 日至 94 年 9 月 30 日
計畫主持人：
陳文章
計畫參與人員：
林佳宏、闕居振、童宜峙、李文亞、徐俊嘉、張雍
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□國際合作研究計畫國外研究報告書一份
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執行單位：國立台灣大學化學工程學系
中 華 民 國 94 年 11 月 15 日
一
目錄
壹.前言...1 貳.Preparation and Characterization of PMSMA/CdS Composite Films ...1 參.Monte Carlo Simulation on Block Copolymer Morphology ... 10 肆. Preparation of Nanoporous MSSQ Films Through Templating PS-PAA Block
Copolymers ...20 伍.Nanostructured Materials prepared from PS-b-P2VP with Different Molecular
Architectures……….. ...33 陸.2002-2005 NSC Project Achievement ...56 柒.2005 ACS National Meeting 出國報告 ... 60
2
壹.前言
本研究計畫乃執行學門前瞻性計畫，從事活 性聚合法製備雙親性嵌段共聚物及其 Cds 複 合膜，三年來我們除於台大建立此一精準高 分子聚合法，並控制其型態、奈米粒子及奈 米孔洞成長，並用於形成階層性超分子;其結 果如後敘述，感謝國科會支持本計畫，三年 來本實驗共發表37 篇 SCI 期刊論文。貳 .
Preparation and Characterization ofPMSMA/CdS Composite Films
一、中文摘要 本研究中利用原子轉移自由基聚合法製 備不同分子量及鏈段長度之PS-b-PMSMA 嵌 段共聚物。GPC 結果顯示在適當的操作條件 下 製 備 所 得 之 PS-b-PMSMA 其 分 子 量 在 30,000 以下，其分子量分布可控制在 1.3 以 下。另外，此雙親性之PS-b-PMSMA 嵌段共 聚物的化學結構亦由FTIR 及 NMR 的分析結 果證實。SEM 圖可看出 PS-b-PMSMA 嵌段共 聚 物 在 油 相 溶 劑 中 之 微 胞 大 小 隨 PS 及 PMSMA 鏈鍛大小而不同。XPS、DES 及 SCMS 分 析 亦 證 實 CdS 粒 子 已 成 功 被 製 備 在 PS-b-PMSMA 的複合膜中。由 TEM 及 SEM
圖分析得知所製備複合膜結構為數百 nm 之 compound micelle 中包含許多大小在 4~6 nm 的小微胞(single micelle)。UV-Vis 及 PL 的分 析結果則顯示本實驗中所得到的懸浮 CdS 粒 子其最大吸收及發射波長隨 CdS 粒徑大小增 加而有紅移的現象產生，且 CdS 的顆粒大小 約為 4-5 nm。由本研究可知由雙親性嵌段共 聚物PS-b- PMSMA 可控制 CdS 之成長粒徑並 形成compound micelle 中有 single micelle 之 結構，並具發光特性，這將於多層結構之光 電複合薄膜將極具應用潛力。 關鍵詞：原子轉移自由基聚合法、雙親性嵌 段共聚物、PS-b-PMSMA、PS-b-PMSMA/CdS 複合膜 Abstract
In this study, block copolymers of PS-b-PMSMA with various molecular weight and block length were synthesized by atom transfer radical polymerization (ATRP). The GPC analysis showed that the molecular weight distribution of the prepared PS-b-PMSMA could be controlled to be lower than 1.3 for the molecular weight less than 30,000. The chemical structures of the amphiphilic block copolymers of PS-b-PMSMA were well identified by FTIR and NMR. The TEM and SEM images showed that the lengths of PS and PMSMA segments could control the size of micelles in solution or film. The morphology of the composite films exhibited as several hundred nm compound micelles contained a few 4-6 nm single micelles. The results of XPS、 DES and SCMS analysis indicated that the nano-size CdS particles have been successfully prepared in the PS-b-PMSMA composite films. The UV-Vis and PL analysis also revealed that the λmax of prepared CdS particles were red-shift as the CdS particle size increased. Besides, the diameter of CdS particles estimated from Brus formula was about 4-5 nm. Our study demonstrated the successful preparation of CdS/polymer composite films with controllable structure within structure morphology, which would be potential used for multifunctional optoelectronic composite films.
Keywords: ATRP, Amphiphilic block
copolymer, Polystyrene-b-3-(trimethoxysilyl)- propyl methacrylate, CdS, Composite film.
3 二、研究目的 雙 親 性 嵌 段 共 聚 物(Amphiphilic block copolymers, ABC)已被廣泛應用於半導體奈 米粒子之成長，這主要是它可藉由分子結構 (高分子主鏈上的重複單位、不同親疏水段的 鏈段長度)及不同溶劑種類產生特殊型態之 微相分離，可用來精準控制奈米微粒之成 長。然而，目前以 ABC 製備奈米微粒尚有 下列問題尚待解決：（1）嵌段共聚物分子結 構及微胞形態與所合成奈米粒子粒徑大小 及分布之關係建立；（2）奈米粒子於嵌段共 聚物中之成長動力學研究；（3）含奈米粒子 之高分子薄膜欠缺耐熱性及機械性質等問 題。因此，本研究之目的即是要探討解決上 述問題，並以雙親性嵌段共聚物之結構型態 結合倍半聚矽氧烷以達到控制半導體奈米 粒子粒徑大小及分布之目的。 本研究乃為三年計畫，在第一年度已建 立以原子轉移自由基聚合法製備不同鏈段比 例及分子量之雙親性嵌段共聚物。第二年度 是以原子轉移自由基聚合法製備不同鏈段比 例及分子量之PS-b-PMSMA 雙親性嵌段共聚 物，且針對製備條件對共聚高分子之分子量 大小、分佈與分子鏈段長度變化的影響加以 詳細研究，以建立控制分子量及鏈段長度之 方法，並探討block 鏈段長度及溶劑種類對其 所形成微結構形態之關係。本年度則將雙親 性嵌段共聚物結合半導體奈米粒子，以控制 奈米粒子的大小，並探討其薄膜之發光效率 及顏色調控能力的改變。 三、研究方法 1. 藥品與材料 3-(trimethoxysilyl)propyl methacrylate (MSMA, 98%, Aldrich), Styrene (Fluka, > 99%), Methyl 2-bromopropionate (Aldrich, 98%), Copper(Ⅰ)bromide (CuBr, Aldrich 99.999%), Copper(Ⅱ)bromide(CuBr2, 99.999%, Aldrich), N,N,N’,N’,N”- pentamethyl diethylene-triamine
(PMDETA , 99% Aldrich,), Anhydrous tetrahydrofuran (THF, 99.9%, Acros), Anhydrous anisole (Aldrich, 99.7%) ， Cadmiumnitrat-4-hydrat (Cd(NO3)2.4H2O , 99%. Acros), Sodiurn sulfide (NaS.9H2O, Acros) and Dimethyl sulfoxide (DMF, TEDIA)
2. PS-b-PMSMA 製備之方法 圖 1 為雙親性嵌段共聚物 PS-b-PMSMA 製備條件與反應流程。本研究是以原子轉移 自由基聚合法製備高分子共聚物，主要是以 溴化亞銅與烷基胺類(PMDETA)形成之錯合 物為觸媒系統，在適當之反應條件與組成下 製備不同分子量與鏈段長度之 PS-b-PMSMA 高分子共聚物，其反應條件與組成分別列於 表1。 3. CdS/PS-b-PMSMA 薄膜之製備方法 取 不 同 分 子 量 與 鏈 段 長 度 之 PS-b-PMSMA(0.077mmole)高分子共聚物，溶 於無水 anisole(5ml)溶劑中攪拌 3 小時以形成 均 勻 微 胞 形 態 溶 液 ， 再 將 Cd(NO3)2- 4H2O(0.05M) 溶 於 THF 後 再 加 入 PS-b- PMSMA 之微胞溶液中攪拌 12 小時使 Cd2+進 入微胞形態中。之後，再加入NaS 溶液(0.05M) 此時形成黃色溶液，此即為 CdS 奈米粒子於 微胞中產生所致。再利用1000 rpm、20 秒旋 轉塗佈於矽晶片、玻璃窗及石英片上成膜後 進行各項性質檢測(如圖 2 所示) 。 四、研究成果與討論 圖 3 為目前製備巨起始劑 PS 與雙親性 嵌段共聚物前驅物 PS-b-PMSMA 之分子量及 其分布之 GPC 結果。巨起始劑 PS 分子量在 2000 至 12000 之分子量分布(PDI)均可低於 1.1 以下。PS-b-PMSMA 分子量在 30,000 以下 分子鏈段成長有良好的控制，分子量分布(PDI) 小於1.3。由這些結果顯示，所聚合之雙親性
4 嵌段共聚物之分子量及其分佈可由反應條件 精準控制。(詳細結果如表一所示) 圖 4(a) 為 PS 、 PS-b-PMSMS 及 CdS /PS-b-PMSMA 複合膜之 FTIR 圖結構鑑定結 果 ，PMSMA 主 要 特 性 峰 為 OH 基 在 2800~3600 cm-1有很廣泛之吸收峰、Si-OH 出 現在915 cm-1、Si-O-C 出現在 635 cm-1，而羧 基上之 C=O 出現在 1725 cm-1有很強的吸收 峰 ， 故 由 FTIR 圖 譜 顯 示 成 功 合 成 PS-b-PMSMA 之雙親性嵌段共聚物。 圖 4(b)為 PS、PS-b-PMSMS 及 Cd2+ /PS-b-PMSMA 之 FTIR 圖結構鑑定結果，由 中顯示因為 Cd2+ 坎入 PS-b-PMSM 微胞內使 得 Cd2+與 PMSMA 之間產生離子鍵結，故圖 中顯示 1725 cm-1之 C=O 吸收峰強度明顯下 降，且Si-OH 由 938 cm-1位移至915 cm-1。另 一方面，1650 cm-1之吸收峰為未形成雙親性 嵌段共聚物之MSMA 的殘存之 C=C 所致，此
些殘存之可MSMA 可在 small micelles 之間形 成橋樑，使small micelles 連結形成 compound micelle。 圖5 為 PS-b-PMSMA 之1H-NMR 圖譜， 其 中 顯 示 PS 主 要 特 性 峰 分 別 出 現 在 δ=1.4~1.9、3.5、6.3~7.3 ppm。圖中顯示除了 PS 主要特性峰以外，PMSMA 特性峰出現在 δ=0.7、1.8~2.0、3.4、4.18、5.9 及 6.1，故由 綜合 FTIR 及 1H-NMR 圖譜顯示成功合成 PS-b-PMSMA 之雙親性嵌段共聚物。 圖6(a)~6(c)分別為不同鏈鍛大小(PS)59- b-(PMSMA)35、(PS)59-b-(PMSMA)24及(PS)108- b-(PMSMA)36在anisole 溶劑中所形成之混成 膜之SEM 圖，而圖 6(d)為(PS)108-b-(PMSMA)36 在anisole 溶劑中所形成之混合溶液之 TEM 圖。圖6(a)~6(c)之混成膜 SEM 圖顯示，微胞 大小分別為50-100nm、100- 200nm 及 300- 400nm，因 anisole 為油相溶劑故所形成的微 胞結構中親油的PS 鏈段裸露在微胞外面，而 較親水的PMSMA 鏈段則在微胞裏面。由比 較圖6（a）及 6（c）可看出，在相近的 PMSMA 鏈段長度下PS 鏈鍛較長時可形成較大的微 胞。反之，由圖6（a）及 6（b）比較知，在 相同PS 鏈鍛下當 PMSMA 鏈鍛為較長時，可 得較小的微胞且微胞的厚度較厚，此乃因 PMSMA 結構中之 SiOCH3較易水解而產生交 聯，故較長鏈鍛的PMSMA 易產生交聯而使 得所形成之微胞更加緊密，以致形成較小的 微胞。另外，圖6（d）中之(PS)108-b- (PMSMA)36 在溶劑中之混合溶液TEM 圖顯示，微胞大小 為100～200nm，此與圖 6（c）中之(PS)108-b- (PMSMA)36混成膜比較下，其微胞尺寸較 小。由此比較知，在相同鏈段長度下當溶液 濃度較高時(圖 6（c）為薄膜狀態)，共聚物產 生聚集的現象越明顯，故會有較大尺寸的微 胞產生。 圖7 為 CdS/PS-b-PMSMA 複合膜之 XPS 圖譜，其中 Cd(3d5/2)及 Cd(3d3/2)分別出現 405 及 411ev；而 S(2P1/2,2P3/2)則出現在 160、166 及 168 ev，其中 168ev 為硫氧化後 之S 原子所產生，166 ev 為 CdS 上的 S 原子， 而160 ev 為 NaS 殘餘的 S 原子，經過定量的 結果比較知 166ev 的面積最大、其次是 168 ev，而 160 ev 面積最小，此結果顯示出反應 後僅有少量的NaS 殘餘。 圖 8(a)及 8(b)分別為 CdS/PS-b-PMSMA 混成溶液之TEM 圖及複合膜之 SEM 圖。由 圖中可看出 compound micelle 內有大小在 4~6nm 的小微胞，稱為「single micelle」。每 個大的compound micelle 中約含有許多 single micelle，其原因為 anisole 溶劑與 MSMA 極性
差異較大，故當醋酸鎘 Cd(Ac)2 水溶液加入
後，PMSMA 聚集形成核(core)且其 SiO-官能
基可藉由靜電吸引力與Cd2+鍵結，而PS 向外
形成殼(shell)，就產生 single micelle。未與 Cd2+ 鍵結MSMA 鏈段會在單一 single micelle 上形 成迴路(Loop)結構，但這在熱力學上會造成系 統謪(Entropy)減少，故為避免系統謪減少，系
5 統 中 之 自 由 MSMA 鏈 段 自 然 會 在 single micelle 之間形成橋樑以使謪(Entropy)增加。 如此就造成compound micelle 的形成。 圖9(a)為 Cd2+/PS-b-PMSMA 在微胞內及 外之EDX 圖。其結果顯示 Cd2+幾乎完全坎入 微胞內，只有極少數的 Cd2+殘餘在微胞外。 圖9 (b)為 CdS/PS-b-PMSMA 在微胞內及外之 EDS 圖，其結果顯示微胞內的 Cd 及 S 比例為 1:1，此更可進一步証明 CdS 粒子已成功的坎 入微胞內，只有極少數的CdS 殘餘在微胞外。 圖10 為 PS-b-PMSMA 薄膜之 AFM 圖。 圖中顯示約有 30~80nm 球狀聚集體可能是 PS-b-PMSMA 在 anisole 之油相溶劑中經過旋 轉塗佈成膜後形成雙親性嵌段共聚物微胞的 聚集體。 圖 11 分 別 為 CdS/ (PS)59 -b- (PM SMA)35 、CdS/ (PS)59-b-(PMSMA)24 及 CdS/ (PS)108-b-(PMSMA)36之 SCMS 圖。由圖中可 看出，CdS 發光奈米粒子聚集在不同鏈鍛大小 之(PS) -b-(PMSMA)所形成的微胞內，因在油 相溶劑中所形成微胞大小不同，故形成了不 同粒徑大小之 CdS 發光奈米粒子聚集體，其 大 小 分 別 為 100-300nm 、 200-400nm 及 100-1000nm，此結果亦可進一步証明 CdS 確 時包含在(PS) -b-(PMSMA)所形成的微胞之 中。 圖12 不同大小之 CdS/PS-b-PMSMA 微胞 複合膜之UV-vis 光譜圖。由圖中可知 λedge分 別出現在447nm 、 452nm 及 463nm 換算成 能階大小約為 2.77、2.74 及 2.67eV。由文獻 知當CdS 的大小比 Bohr radius(6nm)小時，其 激發轉移的能階大小會隨著粒徑越小而增 高，並使得螢光光譜產生藍移現象，此能階 與粒徑大小的關係可由 Brus formula 來表 示，如下： R e m m R h E h e g ε 2 * * 2 2 1 1 1.8 8 ⎥⎦− ⎤ ⎢ ⎣ ⎡ + = ∆ 其中，△Eg 為能階大小的改變量、h 為浦朗 克常數、R 為顆粒半徑、Me*及 Mh*分別為電 子與電洞的有效質量、e 為電荷帶電量、 為 介電常數，將相關之數值帶入後可得所製備 之CdS 粒徑約為 4.32、4.51 及 5.03 nm 左右。 圖13 為不同大小之 CdS/PS-b-PMSMA 微 胞複合膜之PL 光譜圖。由圖中可知 λmax分別 出現在 496 、 499 及 507nm 其結果顯示隨 CdS 粒徑大小增加 λmax有紅移的現象產生。 由本研究可知由雙親性嵌段共聚物PS-b- PMSMA 可 控 制 CdS 之 成 長 粒 徑 並 形 成 compound micelle 中有 single micelle 之結 構，並具發光特性，這將於多層結構之光電 複合薄膜將極具應用潛力。 五、計劃成果自評 1. 本研究研究成果與原設定計畫目標相符 研究目標 研究成果 建立活性聚合法製備 雙親性嵌段共聚物 建 立 ATRP 製 備 PAA ， PS-b-PMSMA並可由製備 條 件 控 制 其 分 子 量 分佈，鏈段比，並開 發 活 性 陰 離 子 聚 合 法 製 備 線 性 及 星 狀 PS-b-P2VP 控制所製備雙親性嵌 段共聚物形態 建 立 雙 親 性 嵌 段 共 聚於選擇溶劑中，其 組 成 與 微 胞 形 態 之 關係，並藉由分子模 擬分析其形態 由雙親性嵌段共聚控 制CdS的顆粒大小 由UV-Vis 及 PL 光譜 圖 証 實 ， 藉 由 PS-b-PMSMA 中 不 同 的 鏈 段 長 度 可 控 制微胞大小，而其內 之 CdS 顆粒大小約 為4-5 nm。
6 製備不同鏈段長度之 PS-b-PMSMA 雙 親 嵌 段 共 聚 高 分 子 及 CdS/PS-b-PMSMA 複 合薄膜 由SEM 、AFM、XPS 、DEX及SCMS分析 亦 證 實 成 功 製 備 不 同 分 子 量 及 鏈 段 比 例 之 PS-b-PMSMA 雙 親 嵌 段 共 聚 高 分 子及 CdS/PS-b-PMSMA 複 合 薄 膜 並 形 成 compound micelle 中有single micelle之 結構，並具發光特性 ，這將於多層結構之 光 電 複 合 薄 膜 將 極 具應用潛力 表1、 (PS)n-(PMSMA)m之組成與反應條件 圖1、PS-b-PMSMA 反應示意圖。 圖2、由嵌段共聚物製備 CdS 奈米粒子之 複合膜之製備流程。 圖3、PS 及 PS-b-PMSMS 之 GPC 圖 圖4（a）PS、PS-b-PMSMS 及 CdS/PS-b -PMSMA 複合膜之 FTIR 圖。 雙親性嵌段共聚物 M:I:Cu(Ⅰ):Cu( Ⅱ):L 時間 (hr) Mn PDI PSM0 (PS)25-(PMSMA)103 90 : 1 : 1 :0 : 1 16 28098 1.50 PSM1 (PS)108-(PMSMA)36 121 : 1 : 1 :0.5 : 1 3 20210 1.36 PSM2 (PS)59-(PMSMA)24 121 : 1 : 1 :0.5 : 1 9 12024 1.40 PSM3 (PS)59-(PMSMA)35 93 : 1 : 1 :0.2 : 1 24 14726 1.46 CH2 CH2 CuBr/PMDETA/MBP 100 oC m CH CH Br 65 oC CuBr/PMDETA/MSMA St PS m CH CH (CH2)3 CH3 CH CH C O Si OCH3 OCH3 H3CO n PS-b-PMSMA 1000 10000 100000 1000000 Mn=12210 PDI=1.35 Mn=11209 PDI=1.09 PS-PMSMA PS Meloecular Weight 4 0 0 0 3 0 0 0 2 0 0 0 1 0 0 0 P S - P M S M A - C d S P S - P M S M A / C d2 + P S - P M S M A P S T ran s m it ta n ce( % ) W a v e n u m b e r ( c m - 1 ) PS-b-PMSMA/CdS nanocomposit film CH2CH2 CuBr/PMDETA/MBP 110 oC m CH CH Br 90 oC CuBr/PMDETA/MSMA St PS m CH CH (CH2)3 CH3 CH CH C O Si OCH3 OCH3 H3CO n PS-b-PMSMA Form micelles by self-assembly
...
Cd(NO3)2 and stirring Cd2+ NaS and stirring CdS Spin coating...
.
CdS PS PMSMA7
圖4（b）PS-b-PMSMS 及 Cd2+/PS-b -PMSMA 之FTIR 圖。
圖5、PS-b-PMSMA 之1H-NMR 圖譜。
圖6(a)、(PS)59-b-(PMSMA)35之SEM 圖。
圖6(b)、(PS)59-b-(PMSMA)24之SEM 圖。 圖6(c)、(PS)108-b-(PMSMA)36之SEM 圖。 圖6(d)、(PS)108-b-(PMSMA)36溶液之TEM 圖 圖7(a):CdS/PS-b-PMSMA 複合膜之 XPS 圖 譜。 CH CH C C CH3 CH2 CH2 CH2 Si (OCH3)3 a b c d e f g h i 920 805 690 575 460 345 230 115 0 2.0x104 4.0x104 6.0x104 8.0x104 1.0x105 1.2x105 Cd(3d3/2) Cd(3s) O(1S) C(1S) Si(2p1/2 2p3/2) S(2P1/2 2P3/2) Cd(3d5/2) Co un ts p e r Se co n d Binding Energy(ev) 4000 3500 3000 2500 2000 1500 1000 500 938 C=C 1650 Cd2+ /PS-PMSMA PS-PMSMA C=O 1725 1362 C=O 1725 916 T ransm it tance( % ) Wavenumber(cm-1)
8 396 398 400 402 404 406 408 410 412 414 416 418 420 1x104 1x104 1x104 Max.405.197ev Max.411.947ev Cd(3d5/2) Cd(3d3/2) C o unt s per S e cond Binding Energy(ev) 圖7(b):Cd(3d)之 XPS 圖譜(CdS/PS-b-PMSMA 複合膜)。 圖7( c): S(2P)之 XPS 圖譜(CdS/PS-b-PMSMA 複合膜)。 圖8（a）CdS/PS-b-PMSMA 混成溶液之 TEM 圖 圖8(b) CdS/PS-b-PMSMA 複合膜之 SEM 圖 圖9: CdS/PS-b-PMSMA 複合膜之 EDS 圖。
圖10(a): (PS) -b-(PMSMA)之 AFM 圖。
160 165 170 0 1x102 2x102 3x102 Max:168.397eV Max:166.147eV Max:160.847eV S(2P1/2, 2P3/2) S(2P1/2, 2P3/2) S(2P1/2, 2P3/2) C oun ts p e r S e co nd Binding Energy(ev)
9 300 350 400 450 500 550 600 PSM1 PSM2 PSM3 Ab s o rp ti o n Welength(nm) 圖 10(b)、CdS/PS-b-PMSMA 複合膜之 AFM 圖。 圖11(a)、CdS/(PS)59-b-(PMSMA)35之SCMS 圖。 圖11(b)、CdS/(PS)59-b-(PMSMA)24之SCMS 圖。 圖11(c)、CdS/(PS)108-b-(PMSMA)36之SCMS 圖。 圖12、不同大小之 CdS/PS-b-PMSMA 微胞複 合膜之UV-vis 光譜圖。 圖13、不同大小之 CdS/PS-b-PMSMA 微胞複 合膜之PL 光譜圖。 400 450 500 550 600 PSM1 PSM2 PSM3 PL In te ns it y (a rb itr a ry u n it ) Wavelength(nm)
10
表2、不同大小之 CdS/PS-b-PMSMA 微胞複 合膜之微包、CdS 量子點大小及 UV、PL 光
譜之λma
參 .
Monte Carlo Simulation on BlockCopolymer Morphology 一、中文摘要 本 研 究 使 用 分 子 模 擬 方 法(off-lattice Monte-Carlo simulation)來進行星狀嵌段共聚 物其分子構形變化的探討，並進一步討論其 微胞的形成，將有助於奈米粒子成長的控 制。當共聚物具有不相溶的分子鏈段或在具 選擇性溶劑的環境下，溶液中可觀察到共聚 物 會 產 生 分 子 內 的 分 相 現 象(intramolecular segregation)。此現象研究中使用不同分子鏈段 間 的 mean-square separation 與 orientation correlation 參數來觀察鏈段間的分相行為。研 究中發現，當共聚分子的鏈段數目增加時會 產生較強的分子內分相程度，而分子鏈段長 度的改變影響並不大。共聚物分子內的分相 程度會影響到共聚物分子間的聚集行為，這 可由計算不同選擇性溶劑環境下的分子間 potential mean force 及 second virial coefficient 來進行兩個共聚物間的引力作用關係的觀 察。在選擇性溶劑中，具 blockarm 的星狀共 聚物可形成單一分子微胞，且這些微胞間會 產生分子間斥力而使其穩定存在。另一方 面，具 heteroarm 的星狀共聚物會形成 Janus 分子內分相而導致分子間的聚集，這個研究 結果提供說明實驗上所觀察到的多分子微胞 的形成。 No Nanocomposite Micelles Size (nm) λedgea (nm) λmaxb (nm) CdS Diameter (nm) PSM-1 (PS)59-(PMSMA)35/CdS 50-100 447 496 4.32 PSM-2 (PS)59-(PMSMA)24/CdS 100-200 452 499 4.51 PSM-3 (PS)108-(PMSMA)36/CdS 300-400 463 507 5.03
20
肆.
Preparation of Nanoporous MSSQ FilmsThrough Templating PS-PAA Block
Copolymers
一、Abstract
In this study, porous poly(methyl silsesquioxane) (PMSSQ) films were prepared by PMSSQ/ amphiphilic block copolymer (ABC) hybrids, followed by spin coating, and multi-step baking. The used ABCs were poly(styrene-b-acrylic acid) (PS-b-PAA) and poly(styrene-b-poly (3-(trimethoxysilyl)propylmethacrylate) (PS-b- PMSMA) synthesized by living polymerization. The characteristic of chemical bonding between ABC and PMSSQ resulted in a significant difference on the morphologies and properties of both the hybrids and their porous derivatives. Both intramolecular and intermolecular hydrogen bonding were existed in the PMSSQ/ PS-b-PAA hybrid and led to a macrophase separation. By modifying the chemical structure from PAA segment to PMSMA, covalent bonding between PMSSQ and PMSMA was formed to prevent macrophase separation and initial pyrolysis of ABC. The modulated DSC results also suggest a significant difference on the miscibility of two hybrid systems. The characteristic of the chemical bonding resulted in the higher retardation on the symmetry to non-symmetry Si-O-Si structural transformation for the case of PMSSQ/PS-b-PMSMA than that of PMSSQ/PS-b-PAA from the FTIR studies. The pore size of the nanoporous thin film from the PMSSQ/PS-b-PMSMA hybrid estimated by TEM was less than 15 nm. The refractive index and dielectric constant of the prepared porous films decreased from 1.354 to 1.226 and 2.603
to 1.843 as PS-b-PMSMA loading increased from 0 to 50 wt%, respectively. The present study suggests that the chemical bonding in the hybrid materials plays a significant role on preparing low dielectric constant nanoporous films.
Keywords: block copolymers, films,
33
伍 .
Nanostructured Materials preparedfrom PS-b-P2VP with Different Molecular Architectures
一.Low Dielectric Constant Nanoporous
Poly(methyl silsesquioxane) using Poly
(styrene-block-2-vinylpyridine) as a Template (In collaboration of Prof. Hsin-Lung Chen of National Tsing-Hua University)
Abstract
Low dielectric constant nanoporous poly(methyl silsesquioxane (PMSSQ) was prepared through the templating of an amphiphilic block copolymer, poly(styrene-b-2-vinylpyridine) (PS-b-P2VP). The experimental and theoretical studies suggest that the intermolecular hydrogen bonding interaction is existed between the PMSSQ precursor and PS-b-P2VP. The result of modulated differential scanning colorimeter (MDSC) indicates the miscible hybrid of the PMSSQ precursor /PS-b-P2VP. The miscible hybrid and the narrow thermal decomposition of the PS-b-P2VP lead to nanopores in the prepared films from the results of transmission electronic microscopy (TEM), atomic force microscopy (AFM), and small angle X-ray scattering (SAXS). The effects of the loading ratio and the PS block volume ratio (fPS: 0.74, 0.46 and 0.35) on the morphology and properties of the prepared nanoporous PMSSQ films were investigated. The AFM and TEM studies suggest that the uniform pore morphology should be prepared from a modest porogen loading level for the optimum intermolecular hydrogen bonding. The PS-b-P2VP with a smaller fPS requires a higher
loading level to obtain the uniform pores. The refractive index and dielectric constant of the prepared nanoporous films could be tuned by the loading ratio in the range of 1.361 ~ 1.139 and 2.359 ~ 1.509, respectively. However, both properties are independently on the fPS. The prepared study demonstrates the control of the morphology and properties of the nanoporous films through the polymer structure.
45
二 .Molecular Architecture Effect on the
Microphase Separations in Supramolecular Comb-Coil Complexes of Polystyrene-
block-Poly(2-vinylpyridine) with Dodecyl-
benzene Sulfonic Acid: (AB)nAn Block-Arm
Star Copolymer
(In collaboration of Prof. Hsin-Lung Chen of National Tsing-Hua University)
Abstract
We studied the supramolecular comb-coil block copolymers formed by stoichiometric complexations of an amphiphilic surfactant, dodecylbenzene sulfonic acid (DBSA), with the poly(2-vinylpyridine) (P2VP) blocks in a linear polystyrene-block-poly(2-vinylpyridine)
(PS-b-P2VP) and a non-linear block-arm star copolymer of the type (PS-b-P2VP)5PS5. The effect of the block copolymer molecular architecture on the hierarchical structures in the ordered state and the relevant order-disorder transitions (ODT) have been revealed using small angle X-ray scattering (SAXS). Both the linear and the block-arm complexes exhibited structure-within-structure morphology in which the larger-scale PS microdomains were embedded in the matrix consisting of the smaller-scale lamellar mesophase organized by the P2VP(DBSA) comb blocks. The order-disorder transition temperature (TODT) of the copolymer domain in the linear complex was significantly higher than that of neat PS-b-P2VP due to the stronger interblock repulsion caused by the increase in the polarity of P2VP blocks upon complexation with DBSA. In sharp contrast the corresponding TODT of (PS-b-P2VP)5(PS)5(DBSA) complex was approximately the same as that of the neat copolymer. In this case the disruption of the
PS microdomains induced a concurrent disordering of the smaller-scale lamellar mesophase because the entropic loss due to excessive stretching of short PS block chains in the microdomains overwhelmed the polar-nonpolar repulsion responsible for the formation of the lamellar mesophase. We have also observed a significant reduction in the interdomain spacing of the copolymer domains in (PS-b-P2VP)5(PS)5(DBSA) complex compared to that in the neat copolymer. The smaller interdomain spacing was attributed to the lower aggregation number of PS star-arms in the microdomains due to chain-crowding effect.
56
陸.
2002-2005 NSC Project Achievement三年來(2002.08.01~迄今)經由國科會經
費支持共發表 43 篇(其中 37 篇為 SCI 期刊論 文，包括 Macromolecules 6 篇, Macromol.
Rapid Commun. 2 篇 , Polymer 7 篇 ,
Chemistry of Materials, J. Materials Chemistry, J. Electrochem. Soc.等期刊)，並獲得兩項中華
民國專利, 目錄如下。
Block Copolymers related publications
1. B Nandan, C. H. Lee, H. L. Chen,* and W. C. Chen*, “Molecular Architecture Effect onthe Microphase Separations in Supramolecular Comb-Coil Complexes of Polystyrene-block-Poly(2-vinylpyridine) with Dodecylbenzene Sulfonic Acid: (AB)nAn Block-Arm Star Copolymer”,
Macromolecules, in press. (SCI)
2. Y. Chang, W. C. Chen, Y. J. Sheng, S. Jiang, H. K. Tao,* “Intramolecular Janus Segregation of a Heteroarm Star Copolymer”, Macromolecules, 38,
6201-6209 (2005). (SCI)
3. Y. Chang, Hsiao-Yang Hsueh, W. C. Chen, and C. I. Huang,*, “Effects of Solvent Addition on Body-Centered Cubic Spheres of Block Copolymers: 1. Neutral Solvent”,
Polymer, 46, 3942-3951 (2005). (SCI)
4. C. C. Yang, P. T. Wu, W. C. Chen,* and H. L. Chen, “Low Dielectric Constant Nanoporous Poly(methyl silsesquioxane) By The Tempating of Amphiphilic Block Copolymer, PS-b-P2VP”, Polymer, 45, 5691-5702 (2004). (SCI)
5. Y. Chang,C. Y. Chen,and W. C. Chen,* “ Poly(Methyl silsesquioxane) (MSSQ)/ Amphiphilic Block Copolymer Hybrids and
Their Porous Derivatives: PS-b-PAA and PS-b-PMSMA”, J. Polym. Sci. Polym. Phys., 42, 4466-4477 (2004). (SCI)
Hybrid Materials Related Publications
1. Long-Hua Lee and Wen-Chang Chen,* “Organic-Inorganic Hybrid Materials from a New Octa(2,3-epoxypropyl)silsesquioxane with Diamines”, Polymer, 46, 2163-2174 (2005).(SCI)
2. C. T. Yen, Y. W. Wang, and W. C. Chen*, “Low Volume Shrinkage Photo-patternable Polyimide/Silica Hybrid Materials for Optical Waveguides”, Polymer, 2005, 46, 6959-6967. (SCI)
3. J. P. Hsu, S.-H. Hung, and W. C. Chen, “ A Theoretical Model on Pore Size Distribution in Low Dielectric Constant Nanoporous Silica Films”, Thin Solid Films, 473, 185-190 (2005). (SCI)
4. M. S. Wei, C. H. Lee, and W. C. Chen,* “Tunable Near Infrared Optical Properties from Trialkoxycapped Poly(methyl methacrylate)-Silica Waveguide Materials “,
ACS Symp. Ser., Chapter 23, (2005).(EI)
5. Y. Y. Yu and W. C. Chen,* “Morphology and Properties of MEH-PPV /silica nanoparticle hybrid films”, Polym. Int., 54, 500-505 (2005). (SCI)
6. M. S. Wei, L. H. Lee, C. C. Chang, and W. C. Chen*, “Tunable Near Infrared Optical Properties from PMMA-Inorganic Oxide Waveguide Materials”, J. Appl. Polym. Sci, 98, 1224-1228 (2005). (SCI)
7. Yu-Jane Sheng, Wei-Jung Lin, and Wen-Chang Chen,* “Network Structures of Polyhedral Oligomeric Silsesquioxane based Nanocomposites: A Monte Carlo
57
Study”, J. Chem. Phys., 121, 9693-9701 (2004). (SCI)
8. W. C. Chen*, W. C. Liu, and P. F. Chen, “Synthesis and Characterization of Oligomeric Phenylsilsesquioxane- -Titania Hybrid Optical Thin Films”, Mater. Chem.
Phys., 83, 71-77 (2004). (SCI)
9. W. C. Liu, Y. Y. Yu, and W. C. Chen,* “Structural Control and Properties of Low Dielectric Constant Poly(hydrogen silsesquioxane) (PHSSQ) Precursors and Their Thin Films”, J. Appl. Polym. Sci., 91, 2653-2660 (2004).(SCI)
10. W.-J. Lin, W. C. Chen*, W. C. Wu, Y.-H. Niu, and A. K. Y. Jen , “ Synthesis and Properties of Star-like Polyfluorenes with a Silsesquioxane Core“, Macromolecules, 37, 2335-2341 (2004). (SCI)
11. W. J. Lin and W. C. Chen,* “Synthesis and
Characterization of Poly(PMDA-ODA)-Methyl Silsesquioxane
Hybrid Optical Thin Films”, Polym. Int., 53, 1245-1252 (2004). (SCI)
12. Y. Y. Yen, C.-Y. Chen, and W. C. Chen,* “Synthesis and Characterization of Organic-inorganic Hybrid Thin Films Form Poly(acrylic) and monodispersed Colloidal Silica” Polymer, 593-601 (2003). (SCI) 13. C. H. Lee and W. C. Chen,* “Synthesis and
Optical Characteristics of Trialkoxycapped Poly(methyl methacrylate)-Silica Hybrid Films”, Tamkang J. Sci. Technol., 6, 73-80 (2003).
14. 31. C. C. Chang, G. S. Wei, and W. C. Chen,* “Spin Coating of Polyimide-Silica Optical Thin Films”, J. Electrochem. Soc.,
150, F147-F150 (2003). (SCI)
15. C. C. Chang, K. H. Wei, Y. L. Chang, and W. C. Chen,* “ Synthesis and Optical
Properties of Poly(BPDA-ODA)/Silica Hybrid Thin Films”. J. Polym. Res., 10, 1-6 (2003). (SCI)
16. Y. Y. Yen and W. C. Chen,* “Synthesis
and Characterization of Organic-inorganic Hybrid Thin Films
Form Acrylic Polymers and water Based Colloidal Silica”, Mater. Chem.
Phys. 82, 388-395 (2003). (SCI)
17. W. C. Liu, Y. Y. Yu, and W. C. Chen,* “Nanoporous Silica Films Derived From Structurally Controllable Poly(Silsesquioxanes) Oligomers By Templating”, Mat. Res. Soc. Symp. Proc. 776, E.7.10 (2003). (EI)
18. C. T. Yen, W. C. Chen,* D. J. Liaw, H. Y. Lu, “Synthesis and Properties of New Organosoluble Polyimide/Silica Hybrid Thin Films Through Both Intrachain and Interchain Bonding”, Polymer, 44, 7079-7087 (2003). (SCI)
19. C. T. Yen, and W. C. Chen,* “Effects of Molecular Structures on The Properties of Polyimides and Photopatternable Polyimide/Silica for Optical Waveguide Applications”, Proc. SPIE 5212, 163-170 (2003). (EI)
20. C. C. Yang, and W. C. Chen,* “The Structures and Properties of Hydrogen Silsesquioxane (HSQ) By Thermal Curing”, J. Mater. Chem., 12, 1138-1141 (2002). (SCI)
21. L. H. Lee, W. C. Chen,* and W. C. Liu, “Structural Control of Oligomeric Methyl Silsesquioxane Precursors and Their Thin Film Properties”, J. Polym.
Sci. Polym. Chem., 40, 1560-1571
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22. C. C. Chang, and W. C. Chen*, “ Synthesis and Optical properties of Polyimide-Silica Hybrid Thin Films”,
Chem. Mater. 14, 4242-4248 (2002).
(SCI)
23. W. C. Chen,* L. H. Lee, B.-F. Chen, and C.-T. Yen, “ Synthesis and Characterization of Poly(methyl silsesquioxanes)-titania Hybrid Optical Thin Films”, J. Mater. Chem. 12, 3644-3648 (2002). (SCI)
24. W. C. Liu, C. C. Yang, W. C. Chen*, B.-T. Dai, and M. S. Tsai, “The Structural Transformation and Properties of Spin-on Poly(silsesquioxane) Films By Thermal
Curing” J. Non. Cryst. Solids. 311, 233-240 (2002). (SCI)
Organic Electronic and Optoelectronic Polymers
1. Fu-Chuan Tsai, Chao-Ching Chang, Cheng-Liang Liu, Wen-Chang Chen,* and
Samson A. Jenekhe*, “New
Thiophene-Linked Conjugated Poly(azomethine)s: Theoretical Electronic
Structure, Synthesis, and Properties”,
Macromolecules, 38, 1598-1966 (2005).
(SCI)
2. R. D. Champion, K. C. Cheng, C. L. Pai, W. C. Chen,* and S. A. Jenekhe,* “ Electronic Properties and Field Effect Transistors of Thiophene Based Donor-acceptor Conjugated Copolymers”, Macromol. Rapid
Commun., 26, 1835-1840 (2005). (SCI)
3. C. L. Liu, F. C. Tsai, C. C. Chang, K. H. Hsieh, J. L. Lin, and W. C. Chen,* ” Theoretical Analysis on the Electronic
Properties of Coplanar Conjugated Poly(azomethines)”, Polymer, 46,
4950-4957 (2005). (SCI)
4. C. C. Chang, C. L. Pai, W. C. Chen,* and S. A. Jenekhe,* “ Spin Coating of Conjugated Polymers for Electronic and Optoelectronic Applications”, Thin Solid Films, 479, 254-260 (2005).(SCI)
5. C. L. Liu, and W. C. Chen*, “Fluorene Based Conjugated Poly(azomethine)s: Synthesis, Photophysical Properties, and Theoretical Electronic Structures”,
Macromol. Chem. Phys., 206,
2212-2222(2005). (SCI)
6. W. C. Chen,* Cheng-Liang Liu, Cheng-Tyng Yen, Fu-Chuan Tsai, Christopher J. Tonzola, Nick Olsen,and S. A. Jenekhe, “Theoretical and Experimental Characterization of Small Band Gap Poly(3,4-ethylenedioxythiophene
methines)”, Macromolecules 37, 5959-5964 (2004). (SCI)
7. Y. Zhu, C.-T. Yen, S. A. Jenekhe,* and W. C. Chen, “ Poly(pyrazinoquinoxaline)s : New n-Type Conjugated Polymers with Highly Reversible Reduction and High Electron Affinity”, Macromol. Rapid Commun., 25, 1829-1834 (2004). (SCI)
8. C. T. Yen, Yung Chang, and W. C. Chen,* “ Effect of Substitution on the Near Infrared Optical Properties of Benzene Derivatives”,
Jpn. J. Appl. Phys., 43, No.8A, 5297-5301
(2004).(SCI)
9. C.-T. Yen and W. C. Chen,* “Effect of Bridged Group on The Near Infrared Optical Properties of Polyimide Derivatives”,
Macromolecules, 36, 3315 (2003). (SCI)
10. C. C. Yang, K. H. Hsieh, and W. C. Chen,* "A New Interpretation of The Kinetic Model for The Imidization Reaction of PMDA-ODA
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and BPDA-PDA Poly(amic acids)",
Polyimides and Other High Temperature Polymers, Ed. By K. L. Mittal., 37-45 (2003).
11. K.-H. Hsieh,* C. H. Kuo, C. A. Dai, W. C. Chen, T. C. Peng, G. H. Ho, “Synthesis and Kinetic Studies of UV-Curable Urethane-acrylates“, J. Appl. Polym. Sci. 91, 3162-3166 (2004). (SCI)
12. M. S. Wei and W. C. Chen,* ”Theoretical Analysis on the Bandwidth of Gradient -index Polymeric Rods Prepared by a Centrifugal Field”, Applied Optics, 42, 2174-2180 (2003). (SCI)
13. W. C. Chen,* J.-H. Liu, Y. Chang, M. H. Wei, and H.-W. Su, “Gradient-index Polymer Optical Fibers (GI POFs): Analysis of fabrication Techniques“ in “Polymer Optical Fibers “, Ed. By H. S. Nalwa, Chapter 2, (2003). (invited review paper)
14. W. J. Lin, C. L. Liu, and W. C. Chen,* “ A General Model for Predicting the Baking Behavior of a Polymer Thin Films form Poly(vinyl acetate)/Methanol”, J. Chin. Inst.
Chem. Engr., 34, 471-479 (2003). (SCI)
獲頒專利 4 項
1. Wen-Chang Chen and Long-Hua Lee, “Process for preparing an optical waveguide component from acrylate/Titania alkoxide composite materials and the prepared optical waveguide component”, US Patent 6852358 (Feb. 5, 2005). 2. 陳文章, 李隆華, 和韋明新, “聚倍半矽 氧烷/金屬烷氧化鈦混成薄膜材料及 其製備方法及用途”, 中華民國發明 專 利 205901 號 (2004.06.21~2023.02.13)。 3. 陳文章, 和林威戎, “有機無機混成薄 膜材料及其製備方法”, 中華民國發 明 專 利 191391 號 (2003.11.21~2022.09.02)。 4. 陳文章, 李隆華, 和韋明新, “丙烯酸酯 /烷氧化鈦複合材料之光波導元件之 製 備 方 法 及 所 製 備 之 光 波 導 元 件”, 中 華 民 國 發 明 專 利 189491 號 (2003.10.21~ 2022.07.29)。
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柒.出國報告
230 屆美國化學會年度秋季會議心得報告 陳文章 台灣大學化學工程系 一、參加會議經過 230 屆美國化學會年會秋季會議(230th American Chemical Society Autumn National Meeting )於 8 月 28 日至 9 月 1 日在美國華盛 頓 DC 特區舉行，此會議乃美國化學會年度兩 大盛會(春季及秋季會議)之一。會議包括四十 多個討論會，內容則涵蓋所有化學相關領 域，如有機化學、無機化學、物理化學、高 分子、分子自排、膠體、及醫藥等。筆者有 興趣的乃是參加高分子相關討論會，在此次 共 有 高 分 子 化 學 （ Division of Polymer Chemistry ） 與 高 分 子 材 料 科 學 及 工 程 （Division of Polymeric Materials, Science and Engineering）兩部分。高分子化學部分， 主要有控制活性自由基聚合、高分子刷狀材 料之近期發展、高分子於分子辨識之應用、 高分子於奈米科技之應用、含氟高分子及生 物高分子等；高分子材料科學及工程則包括 高分子理論模擬前瞻應用、高分子於燃料電 池應用、有機金屬高分子、高分子散射及綠 色高分子化學等。由於筆者目前從事高分子 形態之理論模擬及高分子電子結構之理論分 析，因此參加高分子理論模擬之前瞻方法及 應用，共於此 section 發表 3 篇口頭論文及 1 篇壁報論文，除筆者前往參加此會議外，並 有 3 位學生一同前往參加會議。另外，由於 筆者目前亦從事活性自由基聚合之基礎及應 用研究，因此亦前往此 section 聽講口頭論 二、發表論文之摘要如下1. Molecular Simulation on Intramolecular Janus Segregation of a Heteroarm
Star Copolymer
In this Study, macromolecular conformations of heteroarm star copolymer AnBn are investigated by off-lattice Monte-Carlo simulations. Intramolecular segregation is always observed in selective solvents. However, it also can be found in a common good solvent, which gives block incompatibility. Analogy to dipole moment in electrostatics, the degree of intramolecular janus segregation is characterized by the mean-square separation between A and B blocks, or by the orientation correlation between the two blocks. Study shows that the degree of segregation grows with increasing arm numbers while the effect of arm lengths is insignificant. The influence of the degree of intramolecular segregation on the aggregation behavior in solution can be revealed through interactions between two star copolymers. The potential of mean force and second virial coefficient are calculated for various solvent qualities. The effect of the unimolecular architectures, the segregation structures and solvent qualities on the formation of multimolecular micelles will be discussed.
2. Theoretical Analysis on the Geometries and Electronic Structures of Fluorene-based Conjugated Polymers
Effects of linkage on the optimized geometries and theoretical electronic structures of fluorene-based conjugated polymers are reported, including C=C (PFV), C=N (PFI), N=N (PFAz), C≡C (PFE), –CH= (PFM), and –N= (PFN). The theoretical results suggest that PFV, PFAz,
PFE shows nearly coplanar conformation, but PFI is twisted instead due to electrostatic
repulsion force. The geometry planarity and intramolecular charge transfer play major roles
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on the electronic properties (ionization potential, electronic affinity, and bandgap) of polyfluorenes with various linkages. The alternating aromatic and quinoid structures of PFM and PFN result in a small bond length alternation and thus lead to relatively small bandgaps of 0.81 and 0.99 eV, respectively. The present study suggests that the electronic properties of polyfluorenes could be significant monitored through different linkage on the polymer backbone.
3. Theoretical Analysis on the Geometries and Electronic Structures of Coplanar Conjugated Poly(azomethine)s
In this study, the theoretical geometries and electronic properties of varies aromatic ring based conjugated poly(azomethine)s are investigated. The comparison on the geometry of PPI with those of PPV and PAZ reveals that the non-coplanar conformation of PPI is resulted from the repulsion force between the adjacent hydrogen atoms on the C=N linkage and N-phenylene. The non-coplanar conformation of PPI could be overcome by the five member ring based conjugated poly(azomethine)s. The coplanar configuration or donor-acceptor intrachain charge transfer resulted in small Eg of PEEI, PYYI, PFFI, and
PTTI. The upper valence bandwidth of the
studied five-member ring based poly(azomethine)s is larger than that of PPI. The results suggest that the electronic properties of conjugated poly(azomethine)s could be varied through various ring structure and can be potentially used as transparent conductors or thin film transistors.
4. Theoretical Studies on Thiophene Based Alternating Donor-Acceptor Conjugated
Polymers and Their Model Compounds
In this study, theoretical geometries and electronic properties of thiophene based donor-acceptor (DA) alternating conjugated polymers and their model compounds are reported. The investigated acceptors include thiazole, thiadiazole, thieno[3,4-b]pyrazine,
thieno[3,4-c]thiadiazole, and thiadiazolothienopyrazine, respectively. The
intramolecular charge transfer, bridge length, and bond length alternation were analyzed and correlated with the electronic properties. It was found that the HOMO, LUMO, and band gap of the model compounds was well controlled by the acceptor strength. However, the electronic properties of the DA polymer show a significant different trend as the acceptor strength due to the geometrical transformation. The thiophene- thieno[3,4-b]pyrazine alternating conjugated polymers has a relatively small Eg of 1.04 eV resulted from the quinoid characteristic. The electronic properties of the studied D-A polymers suggest that both the acceptor strength and the stable geometry contribute significantly to the electronic properties.
三、與會心得 1.由此次會議可發現高分子理論模擬之重點 乃在於形態、微結構及鏈段運動，而分子模 擬及自洽平均場理論乃目前常用之模擬方 法，然我國目前從事此研究的學者並不多， 除台大諶玉真及黃慶怡兩位教授外，可說是 十分欠缺的。另因國內高分子研究亦較偏向 應用，學生亦受此一導向影響，因此在此方 面研究人力亦較欠缺，這將會影響我國高分 子基礎科學進展。 2.控制自由基聚合方法我國有多人在此方面
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研究，可惜我國並無學者於此發表邀請演講 或 口 頭 報 告 ， 在 領 先 高 分 子 期 刊
Macromolecules 亦甚少我國學者發表 Living
Free Radical Polymerization，因此未來於此領 域尚需努力。
四、攜回資料
1. 230th 美國化學會議議程表
2. 230th National Meeting Polymer Preprint Autumn Meeting
五、致謝
此次承蒙國科會補助出國開會，特此感謝。 ，特此感謝。
