| Summary: | 博士 === 國立中興大學 === 化學工程學系所 === 96 === Abstract:
(1) Exfoliating smectite montmorillonite into random silicate platelets: A one-step process for exfoliating the layered aluminosilicate is established by using a polyamine exfoliating agent, which was prepared from the partial curing of polyoxypropylene-diamine and diglycidyl ether of bisphenol-A at various molar ratios. The corresponding HCl-treated quaternary salts enabled the ionic exchange of sodium montmorillonite and the formation of intercalated silicates (25-56 Å d spacing) or exfoliated silicates, determined by using X-ray diffraction and transmission electronic microscopy. The exfoliation process is attributed to the conformational stretching of the intercalants in the silicate layers.
(2) Random silicate platelets in the water phase from the extraction process: By adding aqueous NaOH to emulsion (toluene/water mixing), leading to pH increase. Simultaneously, the original emulsion of the POP/silicate hybrid in toluene/water was demulsified in two separate phases. The toluene organic phase dissolved the polyamine exfoliating agents and the silicates in the water phase. The random silicate platelets in water phase had 95 wt % purity.
(3) Self-assembly of silicate platelets piling into fibrous arrays: Individual platelets possessing high-aspect-ratio dimension and ionic character enable to self-assemble into micro-scale fiber bundles after water evaporation. The self-stacking mechanism indicated strong face-to-face ionic charge stacking propensity in triggering a vertical growth, in an average 5 μm length. Under a TEM electron beam bombardment, the fibrous materials of stacked platelets were further transformed into a tube-like arrangement.
(4) Manipulating the assemblages of silicate platelets and fatty amine salts to form a Lotus effect surface: Superhydrophobic surface, exhibiting a high water-droplet contact angle of 157o and a rough surface by SEM, has been generated from a self-assembly of high-aspect-ratio silicate platelets associated with detergent-ranged alkyl amine salts. Anionic silicate platelets in an averaged dimension of 100 × 100 × 1 nm3 enable to self-align into a rough plateau surface. The alkyl amine salts tethered to the platelet surface provide a flexible hydrophobic surface exhibiting the Lotus effect.
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