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Fujimoto K, Ishikawa S, Watanabe K, Ishii H, Suga K, Nagao D. Correlation of Secondary Particle Number with the Debye-Hückel Parameter for Thickening Mesoporous Silica Shells Formed on Spherical Cores. ACS Omega 2021; 6:17734-17740. [PMID: 34278159 PMCID: PMC8280692 DOI: 10.1021/acsomega.1c02293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 06/16/2021] [Indexed: 06/13/2023]
Abstract
Mesoporous silica shells were formed on nonporous spherical silica cores during the sol-gel reaction to elucidate the mechanism for the generation of secondary particles that disturb the efficient growth of mesoporous shells on the cores. Sodium bromide (NaBr) was used as a typical electrolyte for the sol-gel reaction to increase the ionic strength of the reactant solution, which effectively suppressed the generation of secondary particles during the reaction wherein a uniform mesoporous shell was formed on the spherical core. The number of secondary particles (N 2nd) generated at an ethanol/water weight ratio of 0.53 was plotted against the Debye-Hückel parameter κ to quantitatively understand the Debye screening effect on secondary particle generation. Parameter κa, where a is the average radius of the secondary particles finally obtained in the silica coating, expresses the trend in N 2nd at different concentrations of ammonia and NaBr. N 2nd was much lower than that expected theoretically from the variation of secondary particle sizes at a constant Debye-Hückel parameter. A similar correlation with κa was observed at the high and low ethanol/water weight ratios of 0.63 and 0.53, respectively, with different hydrolysis rate constants. The good correlation between N 2nd and κa revealed that controlling the ionic strength of the silica coating is an effective approach to suppress the generation of secondary particles for designing mesoporous shells with thicknesses appropriate for their application as high-performance liquid chromatography column packing materials.
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Affiliation(s)
- Kota Fujimoto
- Department
of Chemical Engineering, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Shunho Ishikawa
- Department
of Chemical Engineering, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Kanako Watanabe
- Department
of Chemical Engineering, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Haruyuki Ishii
- Department
of Sustainable Environmental Engineering, Yamaguchi University, 2-16-1, Tokiwadai, Ube, Yamaguchi 755-0097, Japan
| | - Keishi Suga
- Department
of Chemical Engineering, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Daisuke Nagao
- Department
of Chemical Engineering, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
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Liu Z, Quan K, Li H, Chen J, Guan M, Qiu H. Preparation of Silica-Based Superficially Porous Silica and its Application in Enantiomer Separations: a Review. J Anal Test 2021; 5:242-57. [DOI: 10.1007/s41664-021-00155-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Fujimoto K, Watanabe K, Ishikawa S, Ishii H, Suga K, Nagao D. Pore expanding effect of hydrophobic agent on 100 nm-sized mesoporous silica particles estimated based on Hansen solubility parameters. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2020.125647] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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