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    Title: 利用逆微胞法製備具有二氧化矽奈米粒子材料之結構與性質研究
    Other Titles: The structures and properties of nanosilica materials prepared via reverse micelle method
    Authors: 洪笠尊;Hong, Li-Tzuen
    Contributors: 淡江大學化學工程與材料工程學系碩士班
    賴偉淇
    Keywords: 界面活性劑;逆微胞;水解縮合;二氧化矽;AOT surfacant;reverse micelle;hydrolysis and condensation reaction;Silica
    Date: 2014
    Issue Date: 2015-05-04 09:58:09 (UTC+8)
    Abstract: 本研究以丁二酸二辛酯磺酸鈉(AOT)/水/正己烷構成的逆微胞系統,將其視為微型反應器,在系統中加入二氧化矽的前驅物正矽酸乙酯(Tetraethylorthosilicate;TEOS)於鹼性環境之下進行水解縮合反應,因此逆微胞可以作為模板,控制二氧化矽在內部形成的結構,之後再以溶劑揮發的方式讓系統轉變成高濃度的凝膠材料。
    由FTIR分析,可以觀察到凝膠內二氧化矽在465、792、1102 cm-1波數位置的特徵吸收峰,證明二氧化矽的生成。由流變儀分析逆微胞在內部加入 TEOS水解縮合後,內部生成二氧化矽會導致gel-like態逆微胞由多重鬆弛模數(Multi relaxatuon model)轉變成無論在任何頻率掃描下G’永遠大於G”的凝膠態,且材料在越高AOT濃度、TEOS添加量越多及越小wo值下有較佳的固體彈性性質。由SAXS分析AOT/H2O/Hexane逆微胞系統發現AOT濃度在6m時,其結構為圓柱無規則排列結構;當濃度提升至72m時為圓柱體六角最密堆積(HCP)結構;然而加入TEOS進行水解縮合反應後,無論在低濃度或高濃度均呈現圓柱無規則排列結構。由POM、TEM觀察逆微胞在高濃度時可以看到一束束排列的圓柱狀纖維束;當內部生成二氧化矽後可以看到排列的纖維束較不規整。由TGA分析材料熱穩定性,發現隨著wo值越大,有較差的熱穩定性,推測過量的水會使AOT與二氧化矽在內部排列較鬆散所以有較弱的交互作用力造成熱穩定性下降;隨著TEOS添加量越多,最後殘留二氧化矽也越多,表示TEOS轉化成二氧化矽的比例較高。
    In this study, sodium bis(2-ethylhexyl) sulfosuccinate (AOT) / water / hexane reverse micelle system was regarded as microreactor ,and then adding the precursor of silica,Tetraethylorthosilicate(TEOS),into the reverse micelle system then hydrolysis and condensation reaction occurred in alkaline conditions .Therefore,reverse micelles was regarded as a template which can control the growth structure of silica,then evaporating the solvent to change the system into high concentration gel material.
    By FTIR analysis,we observed the characteristic peaks of the silica in the gel at the band 465 ,792,and 1102cm-1 which means the formation of the silica.By rheometer analysis,the rheological property transformed from gel-like state (Multi relaxatuon model) to gel state (G’>G”at all frequency)after the formation of silica in the reverse micelle.Whith increase of AOT concentration,the amount of TEOS,and lower value of wo,the material has better solid elastic properties(G’).By SAXS analysis,when AOT/water/ hexane reverse micelle system in 6m AOT concentration ,the structure of reverse micelle is no long-range cylindrical structure.When AOT concentration increase to 72m,the structure transform to hexagonally closed-packed cylindrical structure.However,the SAXS results showed no long-range cylindrical structure after the hydrolysis and condensation reaction at low and high concentration .By POM and TEM analysis,the fiber bundle which composed of cylindrical fiber were found at high concentration AOT reverse micelle system .As the silica was generated in reverse micelle,the fiber bundle were randomly oriented.By TGA analysis, with increase of wo value ,the material had poor thermal stability because excess water caused AOT and silica arranged loosely and had weakened interation between each other. With the addition of more TEOS, the more residual silica,which means that the more convertion ratio of silica.
    Appears in Collections:[化學工程與材料工程學系暨研究所] 學位論文

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