الفهرس 
Energy Band TheoryOnly 14 pages are availabe for public view
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Abstract
This dissertation is about the science on an interdisciplinary approach to nanoparticles. Studies on the preparation of Ag nanoparticles using both irradiation and polyol methods are presented. Understanding and controlling the process parameters for nanoparticles growth during synthesis are the keys towards successful fabrication of materials with tailored properties. The relationship between the process parameters, structure and physical properties of nanoparticles has been examined. In this work, we have developed a novel approach to synthesize
PVA/Ag and PVA/PVP/Ag nanocomposite hybrid materials which are
based on the seeded growth of Ag nanoparticles within PVA matrix. In
this synthetic strategy, we first dissolve the silver salt within the polymer matrix to form metallopolymers films with well-defined structures in
which metal centers are embedded directly in the polymer backbone.
Using γ−irradiation and/or PVP, we then utilize the preorganized seed
points, or nucleation sites, to initiate the growth of Ag nanoparticles
directly on the polymer backbone. Effect of irradiation doses, PVP
content and precursor concentration on the formation and size of silver
nanoparticles in the matrix were studied. Structural and optical
characterizations of the samples were carried out by UV-Visible
spectroscopy, X-ray diffraction, transmission electron microscopy,
Fourier transformer infrared spectroscopy (FTIR) and the swelling
properties. The obtained results show that, both irradiation dose and PVP% are
considered as determining factors in controlling the particle size in such a
way that as the irradiation dose and/or PVP% increases the particle size
decreases. The crystallinity degree of the PVA matrix was found to
decrease markedly due to PVP blending, AgNO3 addition and/or
irradiation process.
III The radiation method offers many advantages for the preparation
of metal nanoparticles. Hydrated electrons produced over the course of
irradiation can reduce metal ions to zero-valent metal particles, avoiding
the use of additional reducing agents and the consequent side reactions.
Furthermore, the amount of zerovalent nuclei can be controlled by
varying the dose of the irradiation. Homogeneous formation of nuclei is
favorable as it results in uniformly dispersed nanoparticles. Through this
process we are assured of successful producing a PVA polymer filled by high monodispersed nanosized Ag particles.