| Summary: | 碩士 === 國立中央大學 === 化學工程與材料工程學系 === 101 === Polymer brush can greatly modify the interface structure, physical, and chemical properties of the surface. Typical examples are manipulating the wetting and adhesion of solid, and enhancing colloidal stability and biocompatibility. Therefore, polymer brushes have become one of the most attractive research in recent years. This thesis reports the synthesis and applications of poly-ethylene-glycol (PEG) polymer brushes on surface-assembled monolayer (SAM)-modified silica substrates using grafting-to approach.
The first part of the research focuses on the surface modification using SAMs. Two silane molecules, 3-mercaptopropyl trimethoxysilane (MPS) and n-propyl triethoxysilane (PTS) were used, to generate a monolayer of mixed SAMs onto silica substrate, with various MPS surface coverage. Water contact angle and X-ray photoelectron spectroscopy (XPS) were used to analyze the modified surface properties. PEG polymers with hydroxyl group at one end were used as the model system to study the properties of polymer brushes using grafting-to approach. First, -OH was replaced by -Br by adding PBr3 in the reaction. The -Br end-group was detected by Fourier transform infrared spectroscopy (FT-IR) and Nuclear magnetic resonance (NMR). Since MPS has an end -SH group, PEG with end -Br group can graft onto MPS through C-S coupling with the catalyst, bis (triphenylphosphine)palladium(II) chloride (PdCl2(PPh3)2). We can use water contact angle measurement ,XPS and AFM to check the polymer brush’s grafting statues. This study demonstrates that we can change the surface property via simple surface modification and polymer brush grafting technique.
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