Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/16291
標題: 有機/無機溶凝膠高分子混成材料 (I)納米材料之微結構與形態特性之研究 (II)含偶氮發色團非線性光學材料之合成及其光電特性之研究
Organic-Inorganic Hybrid Composites Material Prepared via Sol-Gel Process. (I)Microstructural and Morphological Characteristics of PS-SiO2 Nanocomposites. (II)Synthesis and Optical Properties in the Sol-Gel Matrix Bearing an Azobenzene Chromophores
作者: 黃元品
Huang, Yuan-Pin
關鍵字: Organic-Inorganic
有機/無機
Hybrid
Sol-Gel
SiO2
NLO
Azobenzene
Chromophores
混成
溶膠/凝膠
矽石
非線性光學
偶氮
發色團
出版社: 化學系
摘要: 有機/無機混成(hybrid)複合材料是一種高功能性材料,應用的範圍很廣,包含應用於分離材料、IC的封裝、光學材料、感應器等,而材料的相容性是製造此有機/無機複合材料很關鍵的因素。本研究主要分為兩部份,在第一部份中探討以溶膠-凝膠製程(sol-gel process)製造有機/無機材料並觀察在微結構下的相行為,第二部分將主要探討二次非線性光學溶凝膠高分子材料的光電特性。 第一部份: 納米材料之微結構與形態特性之研究 本研究成功地利用溶膠∕凝膠程序製備一系列不同SiO2含量之有機無機納米材料(nanocomposites)。首先利用自由基加成反應將苯乙烯與含矽氧烷基結構之甲基丙烯酸酯(methacrylic acid 3-(trimethoxysilyl) propyl ester; MAMSE)在無水的條件下聚合成含矽氧烷之高分子前驅物(copolymer precursors)。將此高分子前驅物在酸水的作用下進行溶膠∕凝膠反應而得到一溶膠∕凝膠混成材料(hybrid sol-gel materials)。此混成材料具有良好之光學透明性(optical transparency)以及分子層級之微相分離結構。這些高分子前驅物及其混成材料之結構以及特性經由紅外線光譜(FTIR spectra)、核磁共振光譜(1H-NMR spectra)、微差掃描熱卡計(DSC)以及熱重分析儀(TGA)定性之。至於結構對混成材料之形態學(morphology)以及熱性質(thermal properties)上的影響可由掃描式電子顯微鏡(SEM)、mapping photographs、以及高解析度固態29Si-及13C-NMR spectra得到證實。由這些結果顯示此類混成材料中高分子與矽石間的相容性主要來自於結合高分子以及矽石間的化學鍵。此化學鍵結不僅限制了矽氧烷的水解,同時也降低了矽醇的聚集。另外,在本研究中亦發現在高分子前驅物的熱處理過程中MAMSE會有水解以及酯交換的現象產生。此現象亦對混成材料的相容性有相當大的幫助。至於混成材料的熱性質主要是由於矽石結構的產生所影響。 第二部份:含偶氮發色團非線性光學材料之合成及其光電特性之研究 本研究利用偶氮化反應合成一系列含不同柔軟鏈段結構之非線性光學發色團,並利用溶凝膠反應將這些與三聚氰胺相結合,形成溶凝膠高分子預聚物。這些預聚物經由極化/熟化程序後可得到一系列具有大的非線性光學係數(d33)之高分子材料(HA1, HH1, ASH以及ASP),其中以高發色團含量之HA3及HH3非線性光學三聚氰胺所得到之d33最高(HA3, d33=28.65 pm/v; HH3, d33=26.85 pm/v)。 本研究利用形態學、熱穩定行為、時間穩定行為以及KWW緩和行為方程式探討發色團與三聚氰胺間的相容性以及穩定特性。在SEM形態學的研究,發現在發色團結構中導入柔軟鏈段有助於發色團與三聚氰胺高分子間的相容性,即使將發色團含量提高至30%仍有良好的相容性。另外,本研究亦發現溶凝膠網狀結構對於SHG訊號的緩和行為有明顯抑制的作用。研究結果發現,即使熱老化的溫度高於T0點,其緩和行為仍受網狀結構相當大的影響。 在非線性光學材料的動態熱穩定行為研究中發現,將剛硬之發色團直接接在三聚氰胺中,會對高分子產生一嵌合作用,導致其有效緩和溫度T0值可達83℃之高溫。另外,本研究亦發現增加發色團之柔軟鏈段可能導致T0值得降低(HA1, T0= 82℃; HH1, T0= 78℃)。 在SHG訊號緩和行為與溫度之關係,在有效緩和溫度(T0)以下,其SHG訊號受溫度影響較小,而在有效溫度T0點以上則SHG訊號受熱老化的影響變化較明顯。而由發色團結構變化與SHG訊號時間熱穩定行為中發現,由於矽氧烷結構的導入,可與三聚氰胺形成更緻密的網狀結構,ASH此網狀結構更有效地限制發色團的緩和行為,其所需要之緩和活化能亦高達106 kJ/mole。
ABSTRACT Part I. Microstructural and Morphological Characteristics of PS-SiO2 Nanocomposites A series of organic-inorganic hybrid materials have been prepared by copolymerizing styrene and alkoxysilane-methacrylate via sol-gel process. The alkoxysilane-containing copolymer precursors were synthesized by free-radical copolymerization of styrene with an alkoxysilane-containing monomer, methacrylic acid 3-(trimethoxysilyl)propyl ester (MAMSE), at several feeds. The copolymer precursors were then hydrolyzed and condensed to generate PS-SiO2 hybrid sol-gel materials. The hybrid copolymers possess excellent optical transparency and a nanoscale microphase separation. The copolymer precursors and their hybrid copolymers were characterized by FTIR spectra, 1H-NMR spectra, DSC, and TGA thermograms. Chemical structural effect on the morphology and thermal properties was investigated with SEM, mapping photographs, and high-resolution solid state 13C- and 29Si-NMR spectra. It is found that compatibility between copolymer and silica mainly contributes from incorporating the polymer with silica covalently. Moreover, MAMSE could be hydrolyzed to methacrylic acid and ester-interchanged to silyl methacrylate during heat treatment. This also enhances compatibility between copolymer and silica. Thermal properties of PS-SiO2 hybrid copolymers are improved as silica content increase. However, the presence of silyl ester groups, which were formed during heat treatment, would reduce thermal stability of the hybrid copolymers. Part II. Synthesis and Optical Properties in the Sol-Gel Matrix Bearing an Azobenzene Chromophores. A series of NLO chromophores with several types of spacers have been synthesized. The chromophores were incorporated with melamine-based polymers by sol-gel process to form soluble prepolymers. Excellent optical transparency and large second-order nonlinearities of up to 28 pm/V have been determined afer poling and curing process. Morphological and temporal characteristics were investigated by SEM photograph, relaxation dynamic and temporal relaxation behaviors. Moreover, the relaxation data have been fitted with KWW equation and Arrhenius equation. In morphological characteristics, It is found that compatibility between chromophores and melamine-based polymers can be enhanced by covalently incorporating the polymer with chromophore by a flexible spacer. In the study, no macroscopic phase separation could be observed even the chromophore content of HHAN/melamine system of up to 30 %. In relaxation dynamic, slow relaxation behavior observed at the temperature at or above effective relaxation temperature, T0, mainly contribute from restraint of the sol-gel network in the poled melamine-based NLO polymers. Alternately, high effective relaxation temperature, T0 = 83 ℃, of the HA1 polymer is dominated from an anchor effect cased by directly covalent bonding rigid chromophore into melamine system. In temporal relaxation behaviors, temperature of thermal aging process has a great effect on the relaxation behaviors. A slow variation of the SHG signal relaxation behavior can be observed at temperature below T0. This relaxation behavior depends on degree of cross-linking density. In the ASH polymer system, a more stable temporal stability was found, which mainly contributes from a more condensed network. In the systems, the relaxation data can be fitted by the Kohlrausch-Williams-Watts (KWW) stretched equation. A high characteristic relaxation time, τ = 9000 min, at room temperature and activation energy, Ea =100 KJ/mole, below effective relaxation temperature was found in the ASH polymer.
URI: http://hdl.handle.net/11455/16291
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