Controlled Polymerization in Mesoporous Silica toward the Design of Organic-Inorganic Composite Nanoporous Materials

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• 作者：Minkee Choi ; Freddy Kleitz ; Dinan Liu ; Hee Yoon Lee ; Wha-Seung Ahn ; and Ryong Ryoo
• 刊名：Journal of the American Chemical Society
• 出版年：2005
• 出版时间：February 16, 2005
• 年：2005
• 卷：127
• 期：6
• 页码：1924 - 1932
• 全文大小：355K
• 年卷期：v.127,no.6(February 16, 2005)
• ISSN：1520-5126

文摘

Free-radical polymerization inside mesoporous silica has been investigated in order to open aroute to functional polymer-silica composite materials with well-defined mesoporosity. Various vinylmonomers, such as styrene, chloromethyl styrene, 2-hydroxyethyl methacrylate, and methacrylic acid, werepolymerized after impregnation into mesoporous silicas with various structures, which were synthesizedusing polyalkylene oxide-type block copolymers. The location of the polymers was systematically controlledwith detailed structures of the silica framework and the polymerization conditions. Particularly noteworthyis the polymer-silica composite structure obtained by in situ polymerization after the selective adsorptionof monomers as a uniform film on silica walls. The analysis of XRD data and the N₂ adsorption isothermsindicates the formation of uniform polymer nanocoating. The resultant polymer-silica composite materialscan easily be post-functionalized to incorporate diverse functional groups in high density, due to the openporous structure allowing facile access for the chemical reagent. The fundamental characteristics of thecomposite materials are substantiated by testing the biomolecule's adsorption capacity and catalyticreactivity. Depending on the structure and composition of polymers, the resultant polymer-silica compositematerials exhibit notably distinct adsorption properties toward biomolecules, such as proteins. Furthermore,it is demonstrated that the nanocoatings of polymers deposited on the mesopore walls have remarkablyenhanced catalytic activity and selectivity, as compared to that of bulk polymer resins. We believe that,due to facile functionalization and attractive textural properties, the mesoporous polymer-silica compositematerials are very useful for applications, such as adsorption, separation, host-guest complexes, andcatalysis.