Investigation of PS-P2VP/HAuCl4 Superstructure and its Phase Transformation via Self-Assembly
Date Issued
2006
Date
2006
Author(s)
chang, chü
n chieh
DOI
zh-TW
Abstract
Self-assembly is ubiquitous in nature and has now become as a new approach in science and technology. The organization of inorganic materials into periodic nanostructures by using block copolymers as templates for self-assembling are expected to produce hybrid materials with synergistic improvements in properties. In this thesis, we studied the effect of incorporating inorganic material, chloroauric acid (HAuCl4) in block copolymer template of polystyrene-b-poly 2-vinyl pyridine (PS-P2VP) on the morphology, phase behavior, thermal and optical properties of the hybrid material. PS-P2VPs are prepared by living anionic polymerization. Because of covalent bonding of mutually immiscible polymer blocks, block copolymers form a variety of nanostructures of ordered array of spheres, cylinders or lamellae depending on the volume fraction of their respective block. The nitrogen atom in pyridine ring having an extra lone-pair electrons forms complex with chloroauric acid which in turn changes the superstructure of the PS-P2VP/HAuCl4 hybrid. Superstructure of ordered array of spheres, cylinders, gyroids, lamellae as well as different shapes of micellar phases can be tailored by choosing appropriate block copolymer, by changing molar ratio of the gold salt to the copolymer added as well as the solvent chosen. The phase diagram of the hybrid system are determined and related to intermolecular interactions on nano- and mesoscopic scales. Self-assembled superstructure are characterized by transmission electron microscopy, wide angle and small-angle x-ray scattering. The superstructures are also used to reduce chloroauric acid into a variety of gold chloride and gold nanoparticles by heating the hybrid materials at 140
Subjects
陰離子聚合法
相轉換
聚合度
體積分率
四氫夫喃
二氯甲烷
四氯金酸
anionic polymerization
phase transformation
degree of polymerization
volume fraction
tetrahydrofuran
dichloromethane
hydrogen tetrachloroaurate. trihydrate
Type
thesis
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