Design of Ultra-large-pore Ordered Mesoporous Silicas and Grafting of Organic Groups on Their Surfaces
Item
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Title
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Design of Ultra-large-pore Ordered Mesoporous Silicas and Grafting of Organic Groups on Their Surfaces
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Identifier
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d_2009_2013:38f8d1bf6b8b:11399
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identifier
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11624
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Creator
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Huang, Liang,
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Contributor
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Michal Kruk
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Date
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2012
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry | Materials science | Organic chemistry | Inorganic chemistry | mesoporous silica | surface modification
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Abstract
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Developing novel methods to synthesize ordered mesoporous silicas with ultra-large pores and exploring robust approaches to functionalize their surfaces are two attractive topics in material science. Focused on these two aspects, this dissertation includes the selection of swelling agents for the synthesis of ordered mesoporous silicas templated by commercially available surfactants, and the development of diverse surface modification strategies to graft functional molecules on the surface of ordered mesoporous silicas.;In chapter 2, the synthesis of FDU-12 silicas with face-centered cubic structure of ultra-large mesopores was described. Xylene was identified as a superior swelling agent, which worked perfectly with Pluronic F127 (EO 106PO70EO106). The unit-cell parameter of FDU-12 silicas was expanded up to 56 nm, and the pore diameter reached 36 nm without the loss of structural ordering. The acid treatment effectively suppressed the structural shrinkage. Ethylbezene was proven to be another powerful swelling agent comparable with xylene. Highly ordered closed-pore FDU-12 silicas were prepared via a simple thermally-induced pore closure process at temperatures as low as 400-450 °C.;In chapter 3, grafting of organic groups on surfaces of ordered mesoporous silicas was discussed. Polymers were grafted either by growing from the initiation sites on the surface of the solid support ("grafting from") or attached to the surface by forming covalent bond between the chain ends and the functional groups on the surface ("grafting to"). Polymer/FDU-12 silica composites were obtained by surface-initiated atom transfer radical polymerization (SI-ATRP) or surface-initiated atom transfer radical polymerization with activators regenerated by electron transfer (SI-ARGET ATRP). Good control of the polymerizations was observed in organic and protic media. The Huisgen azide-alkyne cycloaddition "click" reaction and thiol-ene "click" reaction were employed for grafting organic groups to the surfaces of SBA-15 silicas. The alkyne-azide "click" reaction was highly effective for grafting various azide molecules including low-molecular weight polymers to the inner surface of mesopores. The thiol-ene "click" was found less effective but still suitable for the "grafting to" method in nanopores.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Chemistry
