Preparation and Characterization of Nano Porous Silica Particles

• Main Authors: Tsung-Hsien Lin, 林宗賢
• Other Authors: Chen-Yu Wu
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/59719070853483088437

碩士 === 國立中興大學 === 化學工程學系所 === 96 === In this experiment, we used stearylamine (SA) and 3-glycidyloxypropyl- trimethoxysilane (GPS) to synthesize the surfactant, GS, bearing long alkyl chain of silane and we used its property of self-assembling in water phase to synthesize SiO2 shells on the surface of micelles via adding tetraethyl orthosilicate (TEOS). We investigated how the content of TEOS affects the forms and the physical properties of obtained organic/inorganic core-shell structure. Further, we analyzed the appearance of the hollow SiO2 nano-particles made by calcination and its pore shape. By analyzing with FESEM, we found that the SiO2 produced by GS/TEOS could form spherical particles, and the size of the particles increase with the increase of TEOS. When the added TEOS is 5-10 times the weight of GS, the size of SiO2 particles increases from 9.1 nm to 12.2 nm. Further, the size of SiO2 particles increased from 9.6 nm to 11.9 nm in AFM and increased from 11.8 nm to 13.5 nm in TEM. In testing hydrophobic/hydrophilic properties, we find that the surface of SiO2 particles is hydrophobic while the the added TEOS is 3 times the weight of GS. When the added TEOS is 5-10 times the weight of GS, we observed that the SiO2 particles exhibit hydrophilic property. In NMR analysis, when the amout of TEOS was 3-10 times the weight of GS, the Q/T value increased from 4.63 to 20.23. That revealed the content of SiO2 enhanced with the increase of TEOS. In TGA analysis, after analyzing the content of organic/inorganic of the SiO2 particles produced by GS/TEOS, the additive of TEOS increase along with the the content of SiO2. In BET analysis, by analyzing the surface area of SiO2 particles produced by GS/TEOS, we know that the BET surface area increased from 221.1 m2/g to 409.2 m2/g when the added TEOS is 5-10 times the weight of GS. This means that the increase of the amount of TEOS could result in the increase of the surface of SiO2 particles. After removing the organic chains in the particles by calcination and we obtained mesoporous SiO2 particles, which are from 1.9 nm to 2.6 nm pore, and the BET surface area can reach to 765.6 m2/g when the added TEOS is 5 times that of the weight of GS, Combined with the theoretical calculations, when the added TEOS is 5-10 times the weight of GS, we observed that the thickness of the SiO2 shells varies from 2.43 nm to 3.19 nm.