This study covers two major projects. In the first project, polymer-derived ceramics composite of metal and metal silicide nanoparticles (NPs) were synthesized with potential applications in sensing, catalysis, and energy storage. A cost-effective and simple method was developed to produce ceramic (SiOCN) composites with metal and metal silicide NPs through electrospinning, followed by stabilization and pyrolysis. Polyacrylonitrile (PAN) as a carbon source, oligosilazane as a ceramic source, and common metal salts such as silver nitrate (AgNO3) and nickel chloride (NiCl2·6H2O) for metal sources were used. The structural, compositional, and functional properties were investigated by SEM, TEM, EDX, XRD, XPS, FTIR, and SERS. It was found that ceramic fibers with Ag NPs acted as a promising SERS substrate due to the plasmonic resonance properties. Additionally, ceramic composite fiber with Ni-based NPs facilitated the carbon nanotube formation on the fiber. Interestingly, it was revealed that the oligosilazane expanded the interlayer space of graphitic carbon from the polymer, which accelerated the diffusion of NPs to the surface of the composite. The process provided easy control of the composition and operational parameters including pyrolysis temperature, time, and argon flow rate which affected the morphology and properties of the fiber. In another project, stable superhydrophobic polymer coatings were produced from aqueous suspensions of epoxy nanoparticles synthesized from 3-glycidoxypropyl-trimethoxysilane (GPTMS) and perfluorooctyltrichlorosilane (TCFS). The superhydrophobic coatings demonstrated outstanding properties including mechanical robustness and chemical resistance. Aqueous solutions of ionic surfactants, nonionic surfactants, and small organic molecules on superhydrophobic coatings could wet the coatings. However, superhydrophobicity can be recovered by rinsing the surface with water. It was also discovered that, although seemed wetted, the superhydrophobic surface was separated from the solution of ionic surfactant by a layer of ionic surfactant molecules. In contrast, nonionic and small organic molecules could not form a self-assembly monolayer on superhydrophobic surfaces.
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Doctor of Philosophy (Ph.D.)
College of Sciences
Length of Campus-only Access
Doctoral Dissertation (Campus-only Access)
Afrin, Sajia, "In Situ Production of Metal Nanoparticles on Carbon Rich Polymer Derived Ceramic Fibers, and Nanoparticles Suspension Casted Superhydrophobic Coating" (2021). Electronic Theses and Dissertations, 2020-. 632.