Synthesis of Multishelled Silica Particles by Using Choline Hydroxide as Catalyst

We present a facile one-pot strategy for synthesizing multishelled silica particles with precisely controlled structural parameters by using choline hydroxide (ChOH) as catalyst. As an efficient organic base catalyst, ChOH effectively regulates the hydrolysis and condensation kinetics of tetraethyl orthosilicate (TEOS), enabling precise control over the silica network condensation degree. Through systematic manipulation of the ChOH addition sequence and ChOH concentration, the shell multiplicity correlates directly with the ChOH addition sequence, while shell thickness can be fine-tuned by adjusting the ChOH concentration. The subsequent hot water etching process selectively removes lower condensation degrees regions of silica particles, yielding well-defined multishelled architectures. This synthetic approach demonstrates versatility in engineering silica particle structures, from simple monoshelled to complex multishelled architectures, providing new opportunities for designing advanced silica-based materials with potential applications in catalysis, molecular sensing, and drug delivery systems.