Electrostatic interactions in formation of particles from tetraethyl orthosilicate
Electrostatic interactions in formation of particles from tetraethyl orthosilicate
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DOI：
10.1252/jcej.33.468
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发表时间：
2000-06-01
影响因子：
0.8
通讯作者：
Konno, M
中科院分区：
文献类型：
--
作者：
Nagao, D;Kon, Y;Konno, M
通过原位测量颗粒尺寸分布、表面电势和电导率，研究了原硅酸四乙酯 (TEOS) 水解和缩合过程中的颗粒形成机制，包括电解质、KCl 和 LiCl 存在和不存在的情况。实验在 TEOS 浓度为 0.4 mol/dm(3)、水浓度为 11 mol/dm(3) 和铵浓度为 1 mol/dm(3) 下进行。 KCl的添加对粒径的影响比LiCl的影响更大。在KCl浓度为1mmol/dm(3)时，平均粒径达到1μm，并保持粒径的高单分散性。表面电势和电导率的测量表明，添加电解质导致的颗粒尺寸增加是由表面电势的降低和离子强度的增加引起的。还在种子生长实验中检查了电解质的影响。在系统中添加 KCI 可抑制新颗粒的产生，并使种子颗粒的体积增长多达 50 倍。我们的实验结果表明，颗粒之间的静电相互作用是控制颗粒尺寸分布的主导因素。
The particle formation mechanism during hydrolysis and condensation of tetraethyl orthosilicate (TEOS) was studied with in-situ measurements of particle size distribution, electric surface potential and electric conductivity in the absence and in the presence of electrolytes, KCI and LiCl. Experiments were performed at a TEOS concentration of 0.4 mol/dm(3), a water concentration of 11 mol/dm(3) and an ammonium concentration of 1 mol/dm(3). The addition of KCI has a greater effect on the particle sizes than that of LiCl, The average particle size attained 1 mu m at a KCI concentration of 1 mmol/dm(3) maintaining high monodispersity in particle sizes. Measurements of surface potential and electric conductivity show that the increase in particle size by the addition of the electrolytes is caused by both a reduction in the surface potential and an increase in the ionic strength. The effect of the electrolytes was also examined in seeded growth experiments. Addition of KCI to the system suppresses the generation of new particles and enables the growth of seed particles by as much as fifty-fold in volume. Our experimental results show that electrostatic interaction between the particles is the dominant factor in controlling particle size distributions.