Browsing by Subject "porous materials"

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    Nanoporous and Functionalized Polymer Thermosets by Polymerization-Induced Microphase Separation in Bulk, Dilution, and Suspension
    (2021-10) Peterson, Colin
    The microphase separation of diblock polymers allows for excellent control over the nanostructuring of polymer-based materials. Polymers are also readily functionalized and chemically manipulated to alter their chemical properties. Therefore, block polymers represent an important tool in the preparation of precision nanostructured functional materials. Polymerization-induced microphase separation (PIMS) is a convenient and powerful strategy towards the development of such materials. In PIMS, the diblock polymer is simultaneously grown while one block is crosslinked. This captures a non-equilibrium percolating morphology. In this thesis, the morphology is used as a host for photochromic dyes, diluted with solvent to increase the possible porosity, and prepared in suspension to give uniform mesoporous beads.Chapter 1 is a brief overview of key topics relevant to the entire thesis. Chapter 2 describes the incorporation of photochromic dye molecules into a variety of materials from liquid solvent to rigid polymer. PIMS thermosets were created using a liquid-like polycaprolactone derivative and crosslinked polymethylmethacrylate. The liquid-like domains provide an environment for the dye where fast structural relaxation allows for fast dye decoloration while being encased in a rigid matrix. Chapter 3 shifts focus to porous PIMS derivatives. In particular, the effect on the pore size distribution of diluting the monomer solution with solvent to create an organogel is explored. Chapter 4 presents a new synthetic method to prepare beads from PIMS thermosets by performing the chain-growth and cross-linking steps in aqueous suspension. The size of the particles is tuned independently from the size of the pores. Also, functionality is incorporated into the pore walls using a diblock precursor. Chapter 5 provides general conclusions and possible future directions for research relating to disordered diblock thermoset materials.
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    Optimization of Porous Metal Oxides and Metal-Organic Frameworks for High Temperature Catalysis
    (2017-09) May, Camille
    The structural integrity of porous materials is critical to their application as heterogeneous catalysts. For high temperature catalysis, sintering and decomposition are common routes to structural destabilization and ultimately to irreversible deactivation of porous catalysts. This thesis describes the optimization of two types of porous catalysts, namely, porous metal oxides and metal-organic frameworks, for application in solar thermochemical fuel production and high temperature natural gas conversion. Thermochemical cycles can use the heat generated from solar thermal power to split H2O and CO2 into H2 and CO, both of which are valuable fuel and chemical feedstocks. These cycles can be catalyzed by metal oxides. In the first part of this thesis, wood-templating is demonstrated as an approach to generate a macroporous oxide structure that balances high thermal stability and accessible porosity for enhanced thermochemical cycling kinetics. The other part of this thesis describes the development of a silica nanocasting method for the thermal stabilization of metal-organic framework (MOF)-based catalytic metal sites. Nanocasting incorporates a thermally stable silica layer in the MOF pores, which serves as a scaffold for the metal active sites in the MOF after the organic linkers are removed at high temperatures. The work described here shows the applicability of the nanocasting method to MOFs with different pore sizes and compositions, and demonstrates that the method is capable of producing MOF-derived materials that retain their catalytic properties after exposure to high temperatures.