| Summary: | 碩士 === 國立高雄應用科技大學 === 化學工程與材料工程系博碩士班 === 104 === Hollow silica microspheres (HSMS) with different particle sizes were successfully prepared using reverse emulsion polymerization. Effects of different concentrations of alkyl-siloxane with varying polarity and different HLB values (hydrophilic lipophilic balance) of surfactant on the physical properties were also investigated. Tetraethyl orthosilicate (TEOS) was used as a silicate source, and an alkyl-siloxane with polar functional group was used as internal surfactant to prepare the HSMS. A simple way of solvent-etching method was used to form an internal hollow of the microsphere, instead of using the calcination method to remove template. Solvent-etching method can retain the hydroxyl group on the outer surface of the microsphere, which can be further modified to the other functional group or any hydrophilic or lipophilic moiety.
Different concentrations of alkyl-siloxane with varying polarity were used to investigate the effect on the shell thickness of HSMS. Varied HLB values of 6, 7, 8, 10.4, 12 and 13.5 were used to explore the effect on the particle size of HSMS. TEM images show the formation of the internal hollow and the shell thickness. Particle size analyser (PSA) was used to demonstrate the particle size distribution. The results show that the type of polarized alkyl-siloxane significantly affect the formation and internal hollow size of microspheres. Meanwhile, the ratio of (polarized alkyl-siloxane/TEOS) bring about different shell thickness. Small R values produced thinner shell thickness and small values of HLB create a larger particle size.
FTIR (Fourier transform infrared), FE-SEM (field emission scanning electron microscopy), SEM (scanning electron microscopy), EDS (energy dispersive spectrum), Zeta-potential and BET (surface area analyser/porosity analyser) were used as well to investigate the other properties of HSMS.
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