Ultrasonic-Assisted Sol–Gel Synthesis of Core–Shell Silica Particles for High-Performance Liquid Chromatography

Medium-high frequency sonication dominates spherical-SiO2 nanoparticle size

“…Probably, the radicals generated under sonication are also involved in the above reactions [34] . Thus, the sonication can be employed to enhance the hydrolysis and condensation of TEOS [35] . It was possible to produce the smaller SSNs when the reactant ratios were optimized, in particular, when reducing the ammonia concentration during sonication [27] , [34] .…”

Correlation of Secondary Particle Number with the Debye–Hückel Parameter for Thickening Mesoporous Silica Shells Formed on Spherical Cores

“…28 Moreover, the use of a reactant solution with high ionic strength weakens the electrostatic interaction between the ionized silica moieties and the charged cores, which also promotes the diffusivity of the charged silica moieties to the core surface with the same polarity as the silica moiety to suppress the generation of secondary particles. 45,46 Many research groups 15,31,38,47 have attempted to thicken mesoporous shells formed on cores through the suppression of secondary particle generation. The addition of an electrolyte is a promising way to thicken the shell; however, the addition of an excessive amount of electrolyte reportedly leads to the intercore aggregation due to the Debye screening effect.…”

“…The conditions for the synthesis of SiO 2 @ m SiO 2 , including the concentrations of the silica source ,, and core particles, , were varied to control the thickness of the mesoporous shells. A multistep coating process was also employed to further thicken the mesoporous shell. ,, The oil–water biphase stratification reaction, − layer-by-layer method, ,, partial etching method, , and sonication-assisted synthesis method are alternative approaches to control the shell thickness. In the previous reports based on the abovementioned methods, the monodispersity of the core–shell particles was sufficient for their application as column packing materials.…”

“…Many research groups ,,, have attempted to thicken mesoporous shells formed on cores through the suppression of secondary particle generation. The addition of an electrolyte is a promising way to thicken the shell; however, the addition of an excessive amount of electrolyte reportedly leads to the inter-core aggregation due to the Debye screening effect .…”