- 期刊
以嵌段共聚物為模板製備奈米中孔洞材料
Mesoporous Materials Templated by Block Copolymers
摘要
過去幾年中，我們發展出利用一系列以聚氧乙烯 (PEO) 為作為親水基團之嵌段共聚物作為模板，如聚乙烯-block-聚乙氧烯 (Polyethylene-b-poly(ethylene oxide), PE-PEO)、聚氧化乙烯-block-聚己內酯 (Poly(ethylene oxide)-b-poly(ε-caprolactone), PEO-PCL)、及聚乙烯-block-聚乙氧烯-block-聚己內酯 (Polyethylene-b-poly(ethylene oxide)-b-poly(ε-caprolactone), PE-PEO-PCL) 等特有之雙嵌段或三嵌段兩性共聚物，用以製備中孔洞二氧化矽 (mesoporous silica)、中孔洞酚醛樹酯 (mesoporous phenolic resin) 及中孔洞碳材 (mesoporous carbon) 等具備有特殊結構之中孔洞材料。首先我們使用了PE-PEO作為模板，並在揮發導致自組裝 (Evaporation induced self-assembly, EISA) 的過程中改變鹽酸或矽源四乙氧基矽烷 (tetraethyl orthosilicate) 之含量並嘗試以動力學及熱力學之角度出發觀察其中孔結構之變化。後續我們使用了開環聚合 (ring-opening polymerization) 合成了許多不同分子量比例之雙嵌段共聚物 (PEO-PCL) 並以小角度X 光散射 (SAXS, small angle X-ray scattering) 以及穿透式電子顯微鏡(TEM, transmission electron microscopy) 等儀器觀察其結構隨著親疏水區塊體積分率而變之現象，最後，合成了一系列三嵌段共聚物作為模板以製備具有雙孔徑分布之多層次中孔洞二氧化矽 (Hierarchical mesoporous silica) 並鑑定出其多層次結構，在此相關研究中我們可改變酸量、矽源含量、嵌段共聚物之種類以及分子量等實驗條件，藉以調控中孔材料之中間相，以期開拓中孔洞材料的應用層面。
並列摘要
Recently, we have utilized several unique amphiphilic block copolymers as templates, such as PE-PEO, PEO-PCL, and PE-PEO-PCL, to successfully fabricate a series of mesoporous materials, for example, mesoporous silicas, mesoporous phenolic resins and mesoporous carbons by a convenient EISA method. Firstly, we took PE-PEO as model block copolymer to study the TEOS-to-template or HCl-to-template weight ratio effect during the EISA process, view from the thermal dynamic point and kinetic reason, respectively. In addition, we expended the research method to the other block copolymer systems, especially for the unusual ABC type triblock copolymers, we obtained the hierarchical mesostructure by single template. These specific mesostructures could be observed easily by small angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and isotherm N_2 experiment. Moreover, blending technique could also be used in the templating process during EISA, the clear method could easily control the morphology and pore size of the mesoporous materials. In the near future, we expect to obtain great results due to the large surface area of the mesoporous materials with various mesostructures.