Manipulating colloids and surfactants as co-templates for porous nanostructures and nanocomposites.
2010-02
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Manipulating colloids and surfactants as co-templates for porous nanostructures and nanocomposites.
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2010-02
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Abstract
Templating is a general and efficient strategy for creating nanostructured, particularly
nanoporous materials. Two commonly employed classes of templates are colloidal
crystals and surfactants. Colloidal crystals typically have an opal-like structure and have
been used to produce macroporous (>50 nm pores) solids; surfactants generate various
mesoporous structures (2−50 nm pores) as a result of their versatile phase behavior. One
aim of this study is to combine colloidal crystals and surfactants to realize simultaneous
templating at two length scales. A series of hierarchically structured porous silica
samples were synthesized under different synthetic conditions, comprehensive TEM
characterization was conducted to reveal the detailed hierarchical porous structures, and
simulation was performed to correlate the structures to the surfactant phase behavior
within the colloidal crystal confinement. The dual templating approach was further
extended to synthesize functional materials with composite porous architectures, in which
functional cores were embedded in a hierarchically porous framework for optical ionsensing
application. A second aim of this study is to develop a template-based strategy
for sculpting nanoparticles of desired shapes and sizes. Owing to the ordered structure
and symmetry of the template, a templating-disassembly process was found to produce
uniform, nanometer-level, multipodal particles. This method is applicable to a variety of
compositions, including oxides, phosphates and carbon, and it could further lead in-situ
organization of particles following a self-reassembly process. In addition, through a
coupled passivation-disassembly process, site-specific functionalization was achieved to
modify only the tips of the multipods with a range of functional groups, and therefore to
enable their directional bonding to other colloidal particles. (256 words)
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University of Minnesota Ph.D. dissertation. February 2010. Major: Chemistry. Advisor: Andreas Stein. 1 computer file (PDF); xxiv, 178 pages.
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Li, Fan. (2010). Manipulating colloids and surfactants as co-templates for porous nanostructures and nanocomposites.. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/59582.
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